Compiled EST Multiple Choice

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Compiled EST Multiple Choice

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MULTIPLE CHOICES
QUESTIONS IN
Communications Engineering
By: S. S. Cuervo & K. L. N. Suello
400 Solved Problems
TRANSMISSION LINES
1. A parallel wire line spaced at 1.27 cm has a
diameter of 0.21 cm. what is the
characteristic impedance?

Encoded by:
Pante, Riel Djoshua P.

Table of Contents
Transmission Lines
solved
Radio Wave Propagation
solved
Antenna
solved
Noise
solved
Amplitude Modulation
solved
Frequency Modulation
solved

65 problems
39 problems

a. 300 ohms
b. 400 ohms
c. 500 ohms
d. 600 ohms
2. In a coaxial line if the inner diameter is 0.51
cm and the center conductor has a diameter
of 0.22 cm. what is the characteristic
impedance?
a. 50.1 ohms
b. 50.2 ohms
c. 50.3 ohms
d. 50.4 ohms
3. A strip line is formed using a multilayer
board (dielectric constant = 2). The center
track is 0.15 inch wide and 0.005 inch thick
and the PC board first layer thickness is 0.05
inch thick, with an overall board thickness
of twice the single layer. What is the
characteristic impedance?

68 problems
71 problems
101 problems
56 problems

a. 14.7 ohms
b. 14.8 ohms
c. 14.9 ohms
d. 15.0 ohms
4. In an improperly loaded transmission line,
determine the power reflected from the load
if the incident power at the load is 500 W
and the reflection coefficient is 0.71.

________________
Total = 400 problems
solved

a. 252.04 W
b. 252.05 W
c. 252.06 W
d. 252.07 W
5. In wire communications system, calculate
the return loss in dB, if the load impedance
is 600 ohms and the characteristic
impedance of the line is 300 ohms.
a. 9.52 dB
b. 9.53 dB

c. 9.54 dB
d. 9.55 dB
6. The VSWR on a loss free line of 50 ohm
characteristic impedance is 4.2. Determine
the value of the purely resistive load
impedance which is known to be larger than
50 ohms.
a. 210 ohms
b. 211 ohms
c. 212 ohms
d. 213 ohms
7. A micro strip line is formed using a 0.095
inch thick PC board, with a bottom ground
plane and a single 0.15 inch wide, 0.008
inch thick track on the top. What is its
characteristic impedance?
a. 72.1 ohms
b. 72.2 ohms
c. 72.3 ohms
d. 72.4 ohms
8. Determine the impedance of a balanced 2
wire with unequal diameters d1 = 12 mm
and d2 = 10 mm. the spacing between wires
is 30mm.

a. 2.13
b. 2.14
c. 2.15
d. 2.16
12. What is the characteristic impedance of a
coaxial cable using a solid polyethylene
dielectric having a relative permeability of
2.3, an inner conductor of 1 mm diameter
and an outer conductor of diameter 5mm?
a. 63.4 ohms
b. 63.5 ohms
c. 63.6 ohms
d. 63.7 ohms
13. Calculate the velocity factor of a coaxial
cable used as a transmission line, with the
characteristic impedance of 50 ohms;
capacitance is 40 pF/m, and inductance
equal to 50microH/m.
a. 0.0745 ft
b. 0.0746 ft
c. 0.0747 ft
d. 0.0748 ft
14. What is the actual length in feet of a one
quarter wavelength of a coaxial cable with a
velocity of 0.69 at 40 MHz?

a. 35.35 M ohms
b. 35.36 M ohms
c. 35.37 M ohms
d. 35.38 M ohms
9. For a parallel wire line, determine the
conductance if the conductivity is 200 x 10-6
S/m and the conductor diameter spacing is
10mm.

a. 4.23 ft
b. 4.24 ft
c. 4.25 ft
d. 4.26 ft
15. What is the actual length in feet of one half
wavelengths of a coax with velocity factor
of 0.63 at 28 MHz?

a. 1.23mS/m
b. 1.24mS/m
c. 1.25mS/m
d. 1.26mS/m
10. What is the characteristic impedance of an
open line with conductors 4 mm in diameter
separated by 15 mm?

a. 11.07 ft
b. 11.08 ft
c. 11.09 ft
d. 11.10 ft
16. What is the actual length in feet of one
quarter wavelength of a coax with a velocity
factor of 0.68 at 39 MHz?

a. 241.52 ohms
b. 241.53 ohms
c. 241.54 ohms
d. 241.55 ohms
11. The forward power in a transmission line is
150 W and the reverse power is 20 W.
Calculate the SWR on the line.

a. 5.577 ft
b. 5.576 ft
c. 5.575 ft
d. 5.574 ft
17. What is the actual length in feet of a one half
wavelength of a coax with a velocity factor
of 0.61 at 27 MHz?

constant of 2.56
a. 11.10 ft
b. 11.11 ft
c. 11.12 ft
d. 11.13 ft
18. What is the actual length in feet of a one half
wavelength of a coax with a velocity factor
of 0.59 at 26 MHz?
a. 11.16 ft
b. 11.17 ft
c. 11.18 ft
d. 11.19 ft
19. What is the actual length in feet of a one
quarter wavelength of a coax with a velocity
factor of 0.695 at 42 MHz?
a. 4.05 ft
b. 4.06 ft
c. 4.07 ft
d. 4.08 ft
20. An amplifier with a 20 dB gain is connected
to another with 10 dB gains by means of a
transmission line with a loss of 4 dB; if a
signal with a power level of 14 dBm were
applied to the system, calculate the power
output.
a. 11dBm
b. 12dBm
c. 13dBm
d. 14dBm
21. An attenuator has a loss of 26 dB. If a power
of 3 W is applied to the attenuator, find the
output power.
a. 7.54mW
b. 7.55mW
c. 7.56mW
d. 7.57mW
22. What would be the approximate series
impedance of a quarter wave matching line
used to match a 600 ohms feed to 70 ohms
antenna?
a. 204. 94 ohms
b. 204.95 ohms
c. 204.96 ohms
d. 204.97 ohms
23. What is the impedance of a balance 4 wire
with a diameter of 0.25 cm and spaced 2.5
cm apart using an insulator with a dielectric

a. 98 ohms
b. 99 ohms
c. 100 ohms
d. 101 ohms
24. What is the characteristic impedance of a
single wire with diameter d = 0.25 mm
placed at the center between grounded
parallel planes separated by 1 mm apart?
The wire is held by a material with a
velocity factor of 0.75.
a. 71 ohms
b. 72 ohms
c. 73 ohms
d. 75 ohms
25. What is the phase coefficient of a
transmission line at the frequency of 10
MHz if the velocity of propagation is 2.5 x
108m/s?
a. 0.25rad/m
b. 0.26rad/m
c. 0.27rad/m
d. 0.28rad/m
26. Determine the conductance of a two wire
open line with the following parameters; D
= 4 in; d = 0.1 in. and p = 2.6 x108 ohms-m.
a. 2.75 x 10-9 S/m
b. 2.76 x 10-9 S/m
c. 2.77 x 10-9 S/m
d. 2.78 x 10-9 S/m
27. What is the input impedance of a
transmission line if its characteristic
impedance is 300 ohms and the load is 600
ohms? Assume a quarter wavelength
sections only.
a. 149 ohms
b. 150 ohms
c. 151 ohms
d. 152 ohms
28. Determine the standing wave ratio of a 300
ohms line whose load is 400 + j150 ohms.
a. 1.67
b. 1.68
c. 1.69
d. 1.70
29. What proportion of the incident power is

reflected back for the load for a 75 ohms
line terminated with ZL = 50 – j25 ohms.
a. 7.82%
b. 7.83%
c. 7.84%
d. 7.85%
30. What is the attenuation of a 50 ohms coaxial
cable if it has a resistance of 0.121 ohms/m?

a. 7.6 cm
b. 7.7 cm
c. 7.8 cm
d. 7.9 cm
36. Calculate the SWR of the line if the
characteristic impedance of the line is 75
ohms and is terminated by 50 ohms.

a. 1.21 x10 Np/m
b. 1.22 x10-3Np/m
c. 1.23 x10-3Np/m
d. 1.24 x10-3Np/m
31. Find the inductance of a 5 meter length
transmission line if its characteristic
impedance is 52 ohms and the capacitance is
75pF/m.

a. 1.4
b. 1.5
c. 1.6
d. 1.7
37. A transmitter sends a 5 W of power to a 75
ohms line. Suppose the transmitter and the
line is matched but the load is not.
Determine the power absorbed by the
reflection is 0.75.

a. 1.013uH
b. 1.014uH
c. 1.015uH
d. 1.016uH
32. An open wire transmission line with a 2 mm
diameter each separated by 12 mm. calculate
the characteristic impedance.

a. 2.1821 W
b. 2.1822 W
c. 2.1823 W
d. 2.1825 W
38. A generator sends a 250 W of power down a
line. If the SWR of the line is 2.5, determine
the power absorbed by the load.

a. 297 ohms
b. 298 ohms
c. 299 ohms
d. 300 ohms
33. A coaxial cable with inner diameter of 3 mm
and an outer diameter of 9 mm. determine
the characteristic impedance if the dielectric
is polyethylene having ER = 2.3.

a. 204.0 W
b. 204.1 W
c. 204.2 W
d. 204.3 W
39. A 75 ohm characteristics impedance
transmission line is terminated in by a load
impedance of 120 ohms. Determine the
input impedance looking into the line 1
meter long, if the line has a velocity factor
of 0.9 and operates at a frequency of 50
MHz.

-3

a. 43.2 ohms
b. 43.3 ohms
c. 43.4 ohms
d. 43.5 ohms
34. A coaxial transmission line uses Teflon as
dielectric. What is the propagation velocity
if the signal?
a. 207 x 106 m/s
b. 208 x 106 m/s
c. 209 x 106 m/s
d. 210 x 106 m/s
35. A 530 MHz signal is propagating along a
RG 8/u coaxial cable with a velocity factor
0.66. If a 75 degree phase shift is needed,
what is the length if the transmission line?

a. 34.4 – j12.2 ohms
b. 354 – j12.2 ohms
c. 36. 4 – j12.2 ohms
d. 37. 4 – j12.2 ohms
40. A parallel tuned circuit is to be constructed
from a shorted section of parallel wire lie. If
the operating frequency is 2.4 GHz and
dielectric used is polyethylene, what is the
length of the shorted section?
a. 2.0622 cm
b. 2.0623 cm
c. 2.0624 cm

d. 2.0625 cm
41. The transmitter has an output power of 150
W. suppose the line is 50 meters long and
perfectly matched with a loss of 3 dB/100m,
how much power is received in the antenna?
a. 106.1 w
b. 106.2 w
c. 106.3 w
d. 106.4 w
42. TDR equipment receives the signal 250 ns
after the test signal had been transmitted. If
the discontinuity of the line is found 35
meter from the test point, what is the
velocity factor of the line?
a. 0.933
b. 0.656
c. 0.588
d. 0.2685
43. The line has 97% velocity factor. If the two
minima are located 30 cm apart, determine
the frequency.
a. 485 MHz
b. 488 MHz
c. 478 MHz
d. 456 MHz
44. The power incident in the line is 20 W.
assuming the reflected power is 15 W what
is the SWR of the line?
a. 1.71
b. 1.75
c. 1.25
d. 1.26
45. A transmission line 90 meter long has a
characteristic impedance of 75 ohms. The
line is
connected through a 15 V dc
source and 75 ohms source resistance at
time t = 0. What is the voltage across the
input immediately after t = 0?
a.
b.
c.
d.

0 and 7.5 V
1 and 2.3 V
45 and 29 V
69 and 56V

46. A transmission line 90 meter long has a
characteristic impedance of 75 ohms. The
line is connected through a 15 V dc source
and 75 ohms source resistance at time = 0.

The voltage at the input end changes to 10
V, with the same polarity as before, at time t
= 1.5 micro seconds. What is the resistance
that terminates the lines?
a. 465 ohms
b. 896 ohms
c. 563 ohms
d. 150 ohms
47. A parallel wire transmission line has an
inductance of 120 nH/m and a characteristic
impedance of 320 ohms. Calculate the
capacitance of the line.
a. 2.25Pf/m
b. 1.17pF/m
c. 26.25pF/m
d. 15.89pF/m
48. A radio frequency 50 ohms transmission line
is connected to a coil with internal resistance
of 20 ohms and inductive reactance of 5
ohms at a frequency of 10 MHz. the line is
to be matched to the load by means of a
quarter wave line and a stub that are
connected across the load. Calculate the
characteristic impedance of the quarter wave
transformer.
a. 56.2 ohms
b. 32.5 ohms
c. 32.6 ohms
d. 25.3 ohms
49. An open wire line has a 3 mm diameter
separated 6 mm from each other by an air
dielectric. Calculate the characteristic
impedance of the line.
a. 555 ohms
b. 166 ohms
c. 584 ohms
d. 126 ohms
50. A radio frequency coaxial transmission line
has a characteristic impedance of 50 ohms
and is connected across the terminals of a
signal generator. The sending end voltage is
10 V. assuming that the generator, line and
the load are matched; determine the current
which flows into the line.
a. 200 ma
b. 562 ma
c. 100 ma
d. 26 ma
51. A certain instrument measures the input
impedance of a line and gave a reading of
1200 ohms when its far end terminals open
circuited and 300 ohms when it is short

circuited. Calculate the characteristic
impedance of the line.
a. 489 ohms
b. 600 ohms
c. 259 ohms
d. 546 ohms
52. A transmission line has an inductance of 253
nH/m and a capacitance of 56 pF/m. if the
physical length of the line is 1.5 m, calculate
its electrical length at a frequency of 265
MHz.
a. 1.2
b. 1.4
c. 1.6
d. 1.5
53. A radio frequency transmission line has a
capacitance of 46. 8 pF/m and a phase
constant of 30 degree per meter. Determine
the inductance of the line at a frequency of
30 MHz.
a. 148Nh/m
b. 425nH/m
c. 165nH/m
d. 125nH/m
54. The reflected current at the load of a
mismatched line is 3 mA. If the reflection
coefficient of the load is 0.7, what is the
incident current?
a. 4.3 ma
b. 1.2 ma
c. 8.2 ma
d. 1.7 ma
55. A radio frequency transmission lines has a
characteristic impedance of 75 ohms. If the
line is terminating by an aerial with an input
impedance of 72 ohms, calculate the SWR
of the line.
a. 1.04
b. 4.02
c. 6.15
d. 2.06
56. A lossless transmission line is connected to a
10 ohms load. If the SWR = 5. Calculate the
percentage of the incident power that is
dissipated in the load.
a. 89%
b. 56%
c. 15%
d. 23%
57. The reflection coefficient on a loss free line
of 72 ohms characteristic impedance is 60%.
Calculate the load impedance (purely

resistive) and which is smaller than 72
ohms.
a. 56 ohms
b. 18ohms
c. 45ohms
d. 12ohms
58. A radio frequency 50 ohms transmission line
is connected to a coil with an internal
resistance of 20 ohms and inductive
reactance of 5 ohms at a frequency of 10
MHz. the line is to be matched to the load
by means of a quarter wave line and a stub
that are connected across the load. Calculate
the reactance of the stub.
a. 56.2ohms
b. 54.2ohms
c. 83.3ohms
d. 12.2ohms
59. A lossless line has 75 ohms characteristic
impedance and is connected to 50 ohms
load. If the sending end current of 1 mA
flows into the line. Calculate the power
reflected from the load.
a. 3uW
b. 4uW
c. 5uW
d. 6uW
60. A loss free line transmission line has an
inductance of 263.2 nH/m and a capacitance
of 46.8 pF/m. if the generator produces a
sinusoidal voltage at 3 MHz of 2 V peak,
determine the phase change if the line is 3
meter long.
a. 23.25 degrees
b. 11.34 degrees
c. 56.12 degrees
d. 78.2 degrees
61. An AM transmitter sends a 50 W of power
into a 75 ohms lossless coaxial cable. The
input impedance of the antenna at the feed
point is 300 ohms. How much power is
radiated assuming unity gain, no coupling
loss and the antenna is lossless?
a. 56 w
b. 87 w
c. 15 w
d. 32 w
62. A properly terminated line has a line loss of
1 dB/120m. If the power output of the
transmitter is 100 W, how much power
reached the load 30 m away?
a. 12.21 w

b. 94.41 w
c. 26.18 w
d. 110.12 w
63. The output power of the transmitter is 100
W. how strong must the signal be at the
antenna if the antenna is connected to a
transmission line 50 meters long with
reflection coefficient of 0.4 and an
attenuation constant of 5 dB/100m?
a. 47.23 w
b. 15.12 w
c. 7893.12w
d. 154.01 w
64. A coaxial line having an impedance of 50
ohms is used in a cable TV system as drop
cable. If the maximum line voltage are 15 V
and 12 V minimum. What is the SWR of the
line?
a. 4.01
b. 1.24
c. 5.23
d. 1.25
65. An SWR meter is used to measure the
degree of mismatch on the line. The SWR
meter records 1.6 when the line is
terminated with 50 ohms and 2.2 when the
load is change to 176 ohms. What is the
characteristic impedance of the line?
a. 90 ohms
b. 100 ohms
c. 80 ohms
d. 740 ohms
RADIO WAVE PROPAGATION
1. How far away is the radio horizon of an
antenna 100 ft high?
a. 14.14 miles
b. 5.23 miles
c. 144.15 miles
d. 568.1 miles
2. What is the maximum line of sight distance
between a paging antenna 250 ft. high and a
pager receiver 3.5 ft of the ground?
a. 26 miles
b. 25 miles
c. 21 miles
d. 23 miles
3. At a certain time, the MUF for transmissions
at an angle of incidence of 75 degree is 17
MHZ. what is the critical frequency?
a. 2.32 MHz

b. 56.2 MHz
c. 4.4 MHz
d. 10.215 MHz
4. What power density is required to produce
electric field strength of 100 volts per meter
in air?
a. 26.5 W/m2
b. 56.23 W/m2
c. 14.20 W/m2
d. 15.12 W/m2
5. If the critical frequency is 10 MHz in sky
wave propagation, what is the best
frequency to use assuming 30 degree of
radiation angle?
a. 17 MHz
b. 15 MHz
c. 16 MHz
d. 12 MHz
6. In sky wave propagation, what is the critical
frequency if the maximum number of free
electrons in a certain ionosphere later is 1.5
x1012 per cubic meter?
a. 45 MHz
b. 79 MHz
c. 16 MHz
d. 11 MHz
7. In wave propagation, determine the
refractive index of an ionosphere layer with
100 x 106 free electrons per cubic meter at 5
MHz frequency.
a. 1
b. 2
c. 0.3
d. 0.99
8. What is the resultant field strength between
waves travelling in different paths when the
product of the antenna heights above the
reflecting plane is equal to half wavelength
times the total direct distance path between
the two antennas?
a. 1 V/m
b. 2 V/m
c. 0 V/m
d. 3 V/m
9. According to the Philippine Electronics
Code, the maximum accumulated
Permissible Dose of 68 years old man is?
a. 456rems
b. 250rems
c. 123rems
d. 320rems
10. In a VHF mobile radio system, the base

station transmits 100 W at 160 MHz
frequency using half wave dipole antenna 20
meters above ground. Calculate the field
strength at a receiving antenna at a height of
4 meters and a distance of 30 km.
a. 41.78uV/m
b. 12.02uV/m
c. 157.0uV/m
d. 65.48uV/m
11. What is the effective radiated power of a
repeater with 450 W transmitting power
output, 4 dB feed line loss, 6 dB duplexer
loss, and 7 dB circulator loss and feed line
antenna gain of 25 dB?
a. 245.2 w
b. 1254.02 w
c. 2839.31 w
d. 15.21 w
12. A microwave transmitting antenna is 600
feet high. The receive antenna is 240 feet
high. The maximum transmission distance
is?
a. 23.22 m
b. 15 m
c. 487.5m
d. 56.55 m
13. As specified by the National Committee on
Radiation Protection Measurement (USA),
what would be the maximum accumulated
permissible does to the whole body of a 50
year old man?
a. 160rems
b. 125rems
c. 14rems
d. 102rems
14. The total power delivered to the radiator of
an isotropic antenna is 200,000 W.
determine the power density at a distance of
100 meters.
a. 2 W/m2
b. 1.59 W/m2
c. 2 W/m2
d. 459 W/m2
15. Calculate the electric field intensity in mill
volts per meter at 30 kW from a 5 km
source.
a. 189.74 mV/m
b. 456.20 mV/m
c. 14.21 mV/m
d. 158.0 mV/m
16. What is the index of refraction of a certain
substance if a light travel through the

substance at 100 meters at a time is to 140
meters to air?
a. 2.2
b. 1.4
c. 15.2
d. 48.2
17. Determine the critical frequency value of an
HF signal if its maximum usable frequency
is 7050.50 kHz at 35 degrees incidence.
a. 12.22 MHz
b. 5.775 MHz
c. 124.255 MHz
d. 789.02 MHz
18. Determine the effective radiated power of 20
kW TV broadcast transmitter whose antenna
has a field gain of 2.
a. 45kW
b. 12kW
c. 65kW
d. 80kW
19. What is the free space loss, in dB, between
two microwave parabolic antennas 38
kilometer apart operating at 7 GHz?
a. 140.89 dB
b. 12.02 dB
c. 785.1 dB
d. 201.2 dB
20. In sky wave propagation, if the critical
frequency is 25 MHz, what is the best
frequency to use? Assume radiation angle of
45 degree.
a. 23 MHz
b. 45.2 MHz
c. 30 MHz
d. 25 MHz
21. If the maximum number of free electrons in
a certain ionosphere layer is 2 x 1012per m3,
what is its critical frequency?
a. 12.73 MHz
b. 56.2 MHz
c. 154.0 MHz
d. 21.01 MHz
22. What is the refractive index of an
ionosphere layer with 100 x 105 free
electrons per m3? Assume frequency to be at
20 MHz
a. 1
b. 2
c. 0.99
d. 3
23. If the velocity of propagation in a certain
medium is 200 x 106, what is its refractive

index?
a. 1.2
b. 1.5
c. 1.3
d. 1.4
24. What is the propagation velocity of a signal
in a transmission line whose inductance and
capacitance are 5 micro H/m and 20 micro
F/m respectively?
a. 2.02 x 103 m/s
b. 236 x 103 m/s
c. 145 x 103 m/s
d. 100 x 103 m/s
25. AGILA satellite is located 36000 km above
the earth’s surface. Assuming free space
condition what is the path loss of the signal
if the operating frequency is 3 GHz?
a. 193.07 db
b. 23.2 db
c. 489 db
d. 1256.20 db
26. A certain earth station transmitter output
power is 10 kW, transmitting antenna gain
100 dBi, receiving antenna gain 75 dBi,
uplink and downlink frequency of 2.4 GHz
and 2 GHz, respectively. What is the
received signal level at the satellite?
a. 12uW
b. 125uW
c. 45uW
d. 7.71uW
27. The two half wave dipole antennas are
positioned maximum transmission and
reception of signal. If the input power at the
feed point is 150 W, what is the voltage
induced at the feed point if the antennas are
spaced 1 km apart and operating at 126
MHz?
a. 45.21 mV
b. 65.63 mV
c. 12 mV
d. 1254.2 mV
e.
28. A mobile radio system base station is
installed 50 meters above the ground and
transmits 150 W at 54 MHz if the
transmitting antenna gain is 5.17, how far
will the receiving antenna be, if the antenna
height is 30 m and the received field
strength is 22 micro V/m.
a. 153313 m
b. 25421m

c. 125789m
d. 99856m
29. Antenna heights of transmitting and
receiving antenna are found to be 20 meters
and 10 meters respectively. What is the
maximum distance of the two antennas if
troposphere transmission is used?
a. 12.21mi
b. 45.23mi
c. 19.55 mi
d. 65.2mi
30. The antenna is beam 30 degree above the
ground for optimum transmission.
Determine the transmission range, if
ionosphere transmission is used and virtual
height is 200 km. assuming, the earth is flat.
a. 89 km
b. 458 km
c. 564 km
d. 693 km
31. The antenna is beam 10 degree above the
ground for optimum transmission.
Determine the transmission range, if
ionosphere transmission is used and virtual
height is 200 km.
a. 1604 km
b. 5986 km
c. 2015 km
d. 6453 km
32. The signal propagates in fresh water with an
average conductivity of 2.5 S/m. determine
the attenuation coefficient if the relative
permittivity of the medium is 65 and signal
frequency is 3 kHz.
a. 172.02 x10-3Np/m
b. 45 x10-3Np/m
c. 789 x10-3Np/m
d. 15 x10-3Np/m
33. A microwave radio link is installed on a hill
100 m high above the ground. The link is 10
km from the ground station, is set to
transmit 10 W from a parabolic dish having
a gain of 3000 over isotropic. Calculate the
signal strength received if the height of the
ground station is 10 m operating frequency
at 250 MHz.
a. 78.1 mV/m
b. 99.34 mV/m
c. 45 mV/m
d. 56.23 mV/m
34. A VHF radio is to be established via the
ionosphere. Assuming the earth is flat with

the critical frequency of 5 MHz, the angle of
elevation is 45 degree. Calculate the
optimum working frequency.
a. 8 MHz
b. 5 MHz
c. 6 MHz
d. 56 MHz
35. An unknown medium was used in
communication system. If the characteristic
impedance of that medium is 150 ohms,
what is the relative permittivity?
a. 5.23
b. 20.51
c. 2.51
d. 2.54
36. A shortwave transmitter uses sky wave
propagation. What is the angle of incidence
if the MUF is 19 MHz and the critical
frequency is 5 MHz?
a. 45.2
b. 15.36
c. 74.7
d. 15.25
37. What is the critical angle of the signal when
it passes from glass, with relative
permittivity of 7.8 into air?
a. 7.4
b. 5.2
c. 3.2
d. 51.2
38. A TV broadcast station has a transmitting
antenna located 20 m above the ground.
What is the height above the ground of the
receiving antenna 30 km from the
transmitter?
a. 4.5m
b. 7.9m
c. 65.2m
d. 15.25m
39. What is the angle of incidence of the radio
wave signal as it moves from air to glass, if
the angle of refraction is 8.2 degree?
a. 2.93
b. 6.26
c. 8.5
d. 56.2
ANTENNA
1. Two half wave dipole antennas are
positioned for optimum transmission and
reception. Calculate the open circuit
voltage induced in one lambda over 2
dipole when 20 W of power at 250 MHz

2.

3.

4.

5.

6.

7.

is radiated from another lambda over 2
dipole 100 km away.
a. 119.32uV
b. 45.25uV
c. 78.2uV
d. 89uV
For an antenna in a form of a linear
conductor or an array of conductors
calculate the effective length at 3 MHz.
a. 56.2 m
b. 23.5 m
c. 31.83 m
d. 56.3 m
To minimize interference, a 500 MHz
dish needs to have a 1 degree beam
width. What is the corresponding gain in
dB?
a. 56 db
b. 45.2 db
c. 48.2 db
d. 44.7 db
A dish designed for operation at 150
MHz is operated at twice that frequency.
By what factor do gain change?
a. 5
b. 4
c. 3
d. 2
e. 1
What is the power gain in dB of a
uniformly illuminated parabolic reflector
whose half power beam width is 3
degrees?
a. 45.2 db
b. 33.5 db
c. 56.5 db
d. 783db
In aperture antennas for microwave
communications, what is the aperture
number if the angular aperture is 55
degree?
a. 0.48
b. 5.2
c. 48.2
d. 12.2
What is the effective area of a Hertzian
dipole antenna for unity efficiency at 3
MHz?
a. 1190 m2
b. 236 m2
c. 486 m2
d. 1154 m2

8. For an antenna in a form of a linear
conductor, what is the effe3ctive length
at 10.5 MHz?
a. 5.05
b. 2.03
c. 90.3
d. 9.09
9. A certain antenna has a gain of 7 dB
with respect to an isotropic radiator.
What is the effective area if it operates at
200 MHZ?
a. 0.897 m2
b. 12 m2
c. 0.5 m2
d. 0.65 m2
10. Determine the gain of an antenna with
respect to a dipole if its gain with respect
to isotropic is 50 dBi.
a. 4.5 dB
b. 47.86 dB
c. 45.25 dB
d. 96.2 dB
11. If an antenna has a length of 0.125
lambdas then what is the radiation
resistance?
a. 12.34 ohms
b. 78 ohms
c. 14.23 ohms
d. 56.2 ohms
12. What is the horizontal beam width of a
pyramidal horn antenna if its width is
one wave length?
a. 78
b. 23
c. 80
d. 14
13. At 2 MHz, what is the effective area of
the Hertzian dipole for unity efficiency?
a. 2677.5 m2
b. 45.25 m2
c. 7855.2 m2
d. 5699 m2
14. A helical has the following dimensions;
pitch is 1/3 wavelength; diameter is ¼
wavelength and turns is 27. What is the
gain in dB?
a. 45.2 dB
b. 5603 dB
c. 59.2 dB
d. 19.2 dB
15. What is the phase separation of two
antennas 3/8 wavelengths apart?

a. 45
b. 56
c. 135
d. 270
16. A 400 feet antenna is to be operated at
6200 kHz. What is the wavelength at this
frequency?
a. 48.39m
b. 45.26m
c. 23.56m
d. 15.26m
17. A microwave communications uses
plane reflectors as passive repeaters. The
diameter of the parabolic antenna is 18
feet while the effective area is 310 ft2.
Determine the reflector coupling factor.
a. 0.5
b. 0.6
c. 0.9
d. 0.91
18. A TVRO installation for use with a Cband satellite has a diameter of about 3.5
meters and an efficiency of 60%.
Calculate its beam width.
a. 4.2
b. 1.5
c. 2.3
d. 5.2
19. A 500 kHz antenna radiates 500 W of
power. The same antenna produces field
strength equal to 1.5 mV/m. if the power
delivered by the antenna is increased to
1 kW, what would be the expected field
intensity?
a. 2.12 mV/m
b. 45 mV/m
c. 3.13 mV/m
d. 5.2 mV/m
20. What is the effective radiated power of a
repeater with 250 W transmitting power
output, 3 dB feed line loss, 4 dB
duplexer loss, 5 dB circulator loss and
feed line antenna gain of 20 dB?
a. 456.2w
b. 1577.61w
c. 4599.2w
d. 7853.2w
21. What is the length in feet of an antenna
wire for 5 MHz if the antenna is 3.5
waves in length?
a. 688.8 ft
b. 563.23 ft

c. 865.23ft
d. 485.21ft
22. If the antenna current increases 3.4
times, how much does the radiated
power increase?
a. 45.2
b. 11.56
c. 89.2
d. 4.2
23. Determine the effective radiated power
of a transmitter if the input power to the
final amplifier of 370 W with 60%
efficiency if the field gain of the antenna
is 1.3, assuming 100% transmission line
efficiency.
a. 452.1 W
b. 123.2W
c. 784.6W
d. 375.18W
24. The transmitting antenna has a gain of
10 dB, and power output of 6000 W.
determine the effective radiated power.
a. 30000W
b. 40000W
c. 50000W
d. 60000W
25. What is the approximate length of a half
wave dipole antenna radiating at 6450
kHz?
a. 72.5 ft
b. 45.3ft
c. 45.8ft
d. 78.2 ft
26. Determine the approximate length of a
simple whip quarter wave antenna at
UHF frequency of 450.25 MHz.
a. 0.35 ft
b. 0.15ft
c. 0.89ft
d. 0.52ft
27. What is the length if a simple quarter
wave antenna using a VHF frequency of
150. 55 MHz?
a. 1.55 ft
b. 2.63ft
c. 4.25ft
d. 7.23ft
28. Find the approximate width of a
pyramidal horn antenna that will operate
at 10000 MHz intended to have a beam
width 10 degree.
a. 26cm

b. 24cm
c. 45cm
d. 78cm
29. Determine the gain of a 6 ft parabolic
dish operating at 1800 MHZ.
a. 45.12dB
b. 28.17dB
c. 12.5dB
d. 32.02dB
30. A dipole antenna requires to be feed with
20 kW of power to produce a given
signal strength to a particular distant
point. If the addition of a reflector makes
the same field strength available with an
input power of 11 kW. What is the gain
in dB obtained by the use of the
reflector?
a. 8.5 dB
b. 4.6 dB
c. 2.6 dB
d. 1.6 dB
31. What is the gain, in dB of a helical
antenna with diameter of lambda over 3,
10 turns at pitch of lambda over 4, used
at 100 MHz?
a. 18.2dB
b. 16.1dB
c. 52.3dB
d. 17.6dB
32. The frequency of operation antenna cut
to length of 3.4 m.
a. 44.12 MHz
b. 45.2 MHz
c. 78.2 MHz
d. 56.8 MHz
33. What is the effective radiated power of a
repeater with 200 W transmitting power
output, 2 dB feed line loss, 2 dB
duplexer loss, and 3 dB circulator los
and feed line antenna gain of 10 dB?
a. 458 W
b. 398W
c. 896W
d. 126W
34. Determine the dB gain of a receiving
antenna which delivers a microvolt
antenna which delivers a microvolt
signal to a transmission line over that of
an antenna that delivers a 2 micro volt
signal under identical circumstances.
a. -7dB
b. -8dB

c. -9dB
d. -6dB
35. The actual length of the Marconi antenna
used in AM transmitter is 34 m. what is
the operating frequency of the
transmitter, if the velocity factor is 0.9?
a. 5.2 MHz
b. 1.98 MHz
c. 4.2 MHz
d. 3.2 MHz
36. What is the ohmic resistance of the
antenna, if the efficiency of the antenna
is 0.96 and the radiation resistance is 72
ohms?
a. 1
b. 2
c. 3
d. 4
37. What is the gain of a half wave dipole
antenna if the antenna has an efficiency
of 92%?
a. 4.2
b. 1.3
c. 1.6
d. 1.51
38. The output power of an FM transmitter
is 25 W. if the gain of the antenna
referred to isotropic is 50, what is the
ERP of the antenna?
a. 85.23dBw
b. 45.23dBw
c. 89.5dBw
d. 28.83dBw
39. A satellite tracking device uses a helical
antenna that is operating at 1.2 GHz. If
the optimum diameter of the antenna is 8
mc and 10 turns, what is the gain of the
antenna?
a. 42.13dB
b. 15.78dB
c. 15.6dB
d. 15.89dB
40. A helical shape antenna with eight turns
is used to track satellite that is operating
at 1.2 Ghz. If the spacing for the
antennas is 10 cm, what is the beam
width of the antenna?
a. 28.9
b. 56.2
c. 65.3
d. 21.3
41. A certain antenna with twelve turns is

used to operate at a frequency of 1.2
GHz. What is the total length of the
antenna?
a. 75 cm
b. 56cm
c. 23cm
d. 14cm
42. An earth satellite station needed an
antenna that can amplify 2500 times
bigger than the input signal. If the
engineers assigned agreed to build an
antenna with parabolic reflector, and
operates at 3.4 GHz, what is its
diameter?
a. 452 cm
b. 120cm
c. 180cm
d. 5620cm
43. Calculate the operating frequency of a
half wave dipole if the actual length is
3.5 meter.
a. 40.7MHz
b. 21.3 MHz
c. 56.2 MHz
d. 58.1 MHz
44. Calculate the actual length of a half
wave dipole operating at a frequency of
67.25 MHz.
a. 4.2m
b. 1.2m
c. 3.1m
d. 2.12m
45. An antenna with a radiation resistance of
50 ohms and a loss resistance of 3 ohms
receives 150 watts of power from a
transmitter. How much power is radiated
into space?
a. 141.51W
b. 235.21W
c. 563.25W
d. 612.35W
46. An antenna with a radiation resistance of
75 ohms and a loss resistance of 5 ohms,
receives a 150 watts of power from a
transmitter. How much power is wasted?
a. 56.2w
b. 5.35w
c. 154.2w
d. 9.375w
47. What is the efficiency of the antenna if
the radiation resistance is 72 ohms and
the loss resistance is 2 ohms?

a. 89.2%
b. 97.3%
c. 56.2%
d. 100%
48. A half wave dipole with a gain of 2.14
dBi is fed, by means of lossless, matched
line by a 25 watts transmitter. What is
the electric field strength of the signal
measured 15 km from the antenna in free
space in the direction of maximum
radiation?
a. 2.34 mV/m
b. 5.23 mV/m
c. 4.56 mV/m
d. 45.26 mV/m
49. A transmitter supplied 125 watts of
power to an antenna with an efficiency
of 95%. What is the power density
measured at a distance of 30 km from
the antenna in the direction of maximum
radiation? Assume the transmission line
is lossless and perfectly matched.
a. 10.5nW/m2
b. 11.2nW/m2
c. 21.02nW/m2
d. 13.23nW/m2
50. A dipole antenna is designed to have
94% efficiency. Determine the EIRP of
this antenna if it is fed by a 50 watts
transmitter.
a. 14.52dbw
b. 16.72dbw
c. 15.72dbw
d. 18.72dbw
51. Determine the actual length of a Marconi
antenna operating at a frequency of 1625
kHz.
a. 42.85m
b. 41.85m
c. 43.85m
d. 44.85m
52. A parabolic antenna used in the satellite
earth station has a beam width of 3
degree. If the antenna is operating at a
frequency of 14 GHz, what is the
minimum diameter of the antenna?
a. 0.5m
b. 0.6m
c. 0.2m
d. 0.3m
53. A parabolic antenna used in the satellite
earth station has beam width of 3 degree.

What is the gain of the antenna if the
antenna efficiency is 85%?
a. 4256
b. 4587
c. 4567
d. 1546
54. A parabolic antenna used in the satellite
earth station has a beam width of 3
degree. Calculate the effective area of a
3 m dish with an illumination efficiency
of 0.7 at 3 GHz.
a. 5.95m2
b. 6.95 m2
c. 4.95 m2
d. 8.95 m2
55. The signal field strength 10 km from the
Yagi antenna in the optimum direction is
12 mV/m, and 180 degrees from the
optimum direction at the same distance
the field strength is reduced to 2 mV/m.
what is the front to back ratio of the
antenna?
a. 14.6dB
b. 15.6dB
c. 17.6dB
d. 18.6dB
56. A Yagi antenna must be fed with 5 kW
of power to produce the same field
strength at a given point as that of a half
wave dipole antenna fed with 10 kW of
power. Determine the gain of the Yagi
antenna relative to isotropic.
a. 4.14dB
b. 3.14dB
c. 5.14dB
d. 6.14dB
57. Two antennas are fed with equal power.
If the power density measured of the
antenna under test is 2 micro W/m2 and 8
micro W/m2 for the standard antenna.
What is the gain of the antenna under
test referred to dipole if the gain of the
standard antenna is 30 dBi?
a. 20.86
b. 19.86
c. 21.86
d. 22.86
58. A Yagi antenna with front to back ratio
of 10 dB radiates power of 10 watts in
the opposite direction. Determine the
power output of the transmitter, if the
gain of the antenna is 10 dBi?

a. 8W
b. 9W
c. 1W
d. 10W
59. The power radiated on a dipole is 2 W. if
the input power to the antenna is 2.6 W
and the current fed is 2 A, calculate the
ohmic resistance of the dipole.
a. 0.11 ohms
b. 1.2 ohms
c. 0.16 ohms
d. 0.15 ohms
60. The power supplied to the antenna is 5
kW. If the efficiency of the dipole is 0.7,
determine the power loss of the antenna.
a. 2.5kW
b. 3.2kW
c. 6.1kW
d. 1.5kW
61. A half wave dipole is designed to
intercept maximum power at 300 MHz.
calculate the effective aperture of a half
wave dipole.
a. 0.16 m2
b. 0.13 m2
c. 0.12 m2
d. 0.15m2
62. A vertical whip antenna is located in
field strength of 7 mV/m. if the effective
length of the antenna is 1 m. calculate
the voltage induced into the antenna.
a. 7mV
b. 5mV
c. 6mV
d. 9mV
63. An aerial that is mounted vertically is
operating at 3 MHz is 100 m high. It
carries a current that varies linearly from
a maximum of 10 A at the base to 0 A to
the top. Determine the effective height
of the aerial.
a. 200m
b. 300m
c. 100m
d. 400m
64. A half wave dipole requires to be fed
with 10 kW of power to produce 2
mV/m signal strength 5 km from the
antenna. The field strength is measured
again and the result is the same, but this
time a reflector is added to the antenna
and the input power is only 3 kW. What

is the gain of the antenna referred to
isotropic with the additional reflector?
a. 5.37dB
b. 6.37dB
c. 98.37dB
d. 7.37dB
65. An antenna wit parabolic dish reflector
has a beam width of 2 degrees and a gain
of 30 dBi. Calculate the power density at
a range of 5 km at an angel of 1 degree
to the direction of maximum radiation if
the power radiated is 1.8 W.
a. 5.86uW/m2
b. 2.86uW/m2
c. 9.86uW/m2
d. 4.86uW/m2
66. A half wave dipole antenna is used to
operate at 54 MHz. considering end
effect, what is the effective area of the
antenna?
a. 5.64 m2
b. 4.64 m2
c. 9.64 m2
d. 3.64m2
67. A helical antenna is used to track
satellites in space. If the antenna consists
of 15 turns, spacing 15 cm, and diameter
19.1 m, what is the operating frequency
of the antenna to transmit the signal
efficiently?
a. 500 MHz
b. 400 MHz
c. 300 MHz
d. 200MHz
68. A satellite earth station uses an antenna
with parabolic reflector that has a gain of
30 dBi at 3.2 GHz. What is its gain if the
operating frequency is changed to 21.5
GHz, assuming the other parameters
remain the same?
a. 56.55dBi
b. 59.55dBi
c. 58.55dBi
d. 46.55dBi
NOISE
1. The signal to noise ratio is 30 dB at the
input to an amplifier and 27.3 dB at the
output. What is the noise temperature of
the amplifier?
a. 250.1K
b. 249.4K

2.

3.

4.

5.

6.

7.

c. 249.5K
d. 249.6K
A 3 stage amplifier has the following
power gains and noise figures for each
stage; Stage 1, power gain = 10, noise
figure = 3; stage 2, power gain = 20,
noise figure = 4, stage 3, power gain =
30, noise figure = 5. Calculate the total
noise figure.
a. 5.1dB
b. 5.2dB
c. 5.3dB
d. 5.4dB
An amplifier operating over a 4 MHz
bandwidth has a 100 ohms input
resistance. It is operating 27 degree
Celsius, has a voltage gain of 200 and
has input signal of 5 micro Vrms.
Determine rms output noise signal?
a. 512uV
b. 514uV
c. 523uV
d. 515uV
Determine the noise current for a diode
with a forward bias of 1 mA over a 100
kHz bandwidth?
a. 0.0057uA
b. 0.0056uA
c. 0.0024uA
d. 0.0051uA
A transistor amplifier has a measured
S/N power of 10 at its input and 5 at its
output. Calculate the transistors NF.
a. 1
b. 2
c. 3
d. 4
Two resistors, 5 kilo ohms and 20 kilo
ohms are at 27 degree Celsius. Calculate
the thermal noise voltage for a 10 kHz
bandwidth if they are in series.
a. 2.031uV
b. 2.056uV
c. 2.045uV
d. 2.035uV
Calculate the thermal noise voltage of
the two resistors, 5 kilo ohms and 20
kilo ohms at 27 degree Celsius if they
are connected in parallel.
a. 0.91uV
b. 0.54uV
c. 0.81uV

d. 0.56uV
8. Calculate the overall noise figure
referred to the input of a mixer stage that
has a noise figure if 15 dB preceded by
an amplifier that has a noise figure of 6
dB and an available power gain of 20 dB
a. 6.32dB
b. 5.32dB
c. 9dB
d. 4.32dB
9. What is the input equivalent signal to
noise ratio for a receiver with a noise
figure of 15 dB and an output signal
noise to ratio 60 dB?
a. 45dB
b. 65dB
c. 85dB
d. 75dB
10. What is the noise level in a voice
channel if the S/N is 71.25 dB? Express
noise level in pWpO?
a. 45
b. 12
c. 46
d. 42
11. If the occupied baseband of white noise
test signal is 60 – 4028 kHz. Determine
the bandwidth ratio.
a. 35.2dB
b. 31.07dB
c. 38.1dB
d. 36.2dB
12. Calculate the equivalent noise
temperature of a receiver with a noise
figure of 1.5 dB.
a. 119.64K
b. 118.65K
c. 112.63K
d. 118.26K
13. What is the overall signal to noise ratio
in dB of a tandem connection with the
following individual signal to noise
ratio. First stage = 10 dB; second stage =
15 dB and third stage = 20 dB?
a. 5.84dB
b. 8.48dB
c. 5.98dB
d. 5.12dB
14. If all the stages in a tandem circuit have
identical signal to noise of 15 dB, then
what is the overall signal to noise ratio in
dB of the connection when there are 5

stages?
a. 8.05dB
b. 8.06dB
c. 8.01dB
d. 8.02dB
15. In psophometric noise measurement,
what is the psophometric noise power in
pWp if the psophometer reads 10 mV of
noise voltage?
a. 0.167x10-18
b. 0.168x10-18
c. 0.166x10-18
d. 0.165x10-18
16. Determine the effective noise
temperature of an antenna system at the
far end of the feed line if the effective
sky noise temperature is 200 K and
antenna and feed line loss is 10.
a. 289K
b. 288K
c. 282K
d. 281K
17. An amplifier operating over a 2 MHz
bandwidth has an 80 ohms input
resistance. It is operating at 27 degree
Celsius, has a voltage gain of 200 and an
input signal of 6 micro Vrms. Calculate
the output rms noise.
a. 326.6uV
b. 327.6uV
c. 325.6uV
d. 324.6uV
18. An amplifier operating over a 5 MHz
bandwidth has a 100 ohm input
resistance. It is operating at 27 degrees
Celsius, has a voltage gain of 200 and an
input signal of 6 micro Vrms. Calculate
the output rms noise.
a. 573.5uV
b. 574.5uV
c. 575.5uV
d. 576.5uV
19. A transistor amplifier has a measured
S/N power of 100 at its input and 20 at
its output. Determine the noise figure of
the transistor.
a. 6.99dB
b. 6.09dB
c. 6.9dB
d. 6.89dB
20. Convert noise factor of 4.02 to
equivalent noise temperature. Use 300 K

for environmental temperature.
a. 903 K
b. 904 K
c. 905 K
d. 906 K
21. When measuring a voice channel dB test
point level, the meter reads -76 dBm.
Calculate the reading in dBrnCO.
a. 15
b. 16
c. 17
d. 18
22. A diode generator is required to produce
12 micro volts of noise in a receiver with
an input impedance of 75 ohms and a
noise power bandwidth of 200 kHz.
Determine the current through the diode
in milli amperes.
a. 398mA
b. 399mA
c. 400mA
d. 401mA
23. A 3 stage amplifier has stages with the
following specifications; stage 1, power
gain is 10, noise figure is 2; stage 2,
power gain is 20, noise figure is 4, stage
3, power gain is 30, noise figure is 5.
Calculate the total noise figure of the
system, assuming matched condition.
a. 3.65dB
b. 3.66dB
c. 3.67dB
d. 3.68dB
24. 2 resistors rated 5 ohms and 10 ohms are
connected in series and are at 27 degree
Celsius. Calculate their combined
thermal noise voltage for a 10 kHz
bandwidth.
a. 0.04uV
b. 0.05uV
c. 0.06uV
d. 0.07uV
25. A transistor has a measured S/N power
of 60 at its input and 19 at its output.
Determine the noise figure of the
transistor.
a. 2dB
b. 3dB
c. 4dB
d. 5dB
26. A transistor amplifier has a measured

S/N power of 80 at its input and 25 at the
output. Determine the noise figure of the
transistor.
a. 5.04dB
b. 5.05dB
c. 5.06dB
d. 5.07dB
27. A satellite receiver has a noise figure of
1.6 dB. Find its equivalent noise
temperature.
a. 132.2K
b. 131.2K
c. 130.2K
d. 129.2K
28. An amplifier with an overall gain of 20
dB is impressed with a signal whose
power level is 1 watt. Calculate the
power output in dBm.
a. 40dBm
b. 45dBm
c. 50dBm
d. 55dBm
29. The signal power of the input to an
amplifier is 100 micro W and the noise
power is 1 microW. At the output, the
signal power is 1 W and the noise power
is 40 mW. What is the amplifier noise
figure?
a. 6.01dB
b. 6.1dB
c. 6.02dB
d. 6.2dB
30. A 3 stage amplifier is to have an overall
noise temperature no greater than 70
degree K. the overall gain of the
amplifier is to be at least 45 dB. The
amplifier is to be built by adding a low
noise first stage to an existing amplifier
with existing characteristics as follows;
stage 2 has 20 dB power gain; 3 dB
noise figure. Stage 3 has 15 dB power
gain and 6 dB noise figure that the first
stage can have.
a. 0.56db
b. 0.66db
c. 0.76db
d. 0.86db
31. What is the effect on the signal to noise
ratio of a system if the bandwidth is
doubled, considering all other
parameters to remain unchanged except
the normal thermal noise only? The S/N

will be?
a. ½
b. 1/3
c. 2/3
d. 1/4
32. Determine the shot noise for a diode
with a forward bias of 1.40 mA over an
80 kHz bandwidth.
a. 4.nA
b. 5.nA
c. 6.nA
d. 7.nA
33. Given a noise factor of 10, what is the
noise figure in dB?
a. 5dB
b. 10dB
c. 15dB
d. 20dB
34. Express the ratio in decibels of power
ratio 50 is to 10 Watts.
a. 6.59dB
b. 6.99dB
c. 6.79dB
d. 6.89dB
35. The resistor R1 and R2 are connected in
series at 300 degrees K and 400 degrees
K temperature respectively. If R1 is 200
ohms, and R2 is 300 ohms, find the
power produced at the load over a
bandwidth of 100 kHz.
a. 0.497fw
b. 0.496fw
c. 0.495fw
d. .494fw
36. If voltage change is equal to twice its
original value, what is its corresponding
change in dB?
a. 4
b. 5
c. 6
d. 7
37. A 20000 ohms resistor is at room
temperature. Calculate the threshold
noise voltage for a bandwidth of 100
kHz.
a. 5.657uV
b. 5.658uV
c. 5.659uV
d. 5.660uV
38. 3 amplifiers are cascaded together.
Determine the total noise figure in dB if
the noise figure of each amplifier is

equal to 3 dB and the amplifier gain is
10 dB each.
a. 3.24dB
b. 3.25dB
c. 3.26dB
d. 3.27dB
39. For an equivalent noise bandwidth of 10
MHz in a satellite system and a noise
power of 0.0280 pW, determine the
noise density in dBW
a. -205.56dBw
b. -205.59dBw
c. -205.50dBw
d. -205.53dBw
40. 2 resistors, 20 K ohms and 50 K ohms
are at ambient temperature. Calculate for
a bandwidth equal to 100 kHz, the
thermal noise voltage for the 2 resistors
connected in parallel.
a. 4.78uV
b. 4.780uV
c. 4.79uV
d. 5.90uV
41. A receiver connected to an antenna
whose resistance is 50 ohms has an
equivalent noise resistance of 30 ohms.
What is the receiver’s noise
temperature?
a. 174.01K
b. 174.1K
c. 174K
d. 175K
42. The equivalent noise temperature of the
amplifier is 25 K. what is the noise
figure?
a. 0.36dB
b. 0.41dB
c. 0.46dB
d. 0.51dB
43. The signal in a channel is measured to be
23 dB while noise in the same channel is
measured to be 9 dB. The signal to noise
ratio therefore is?
a. 14dB
b. 28dB
c. 42dB
d. 56dB
44. Find the noise voltage applied to the
receiver input if a 300 ohms resistor is
connected in series to a 300 ohms
antenna of a television receiver.
a. 2.70uV

b. 2.7uV
c. 2.80uV
d. 2.8uV
45. A diode noise generator produces 90 nA
in a receiver with an input impedance of
75 ohms, resistive and a noise power
bandwidth of 250 kHz. What must the
current through the diode be?
a. 100.24mA
b. 101.24mA
c. 100.25mA
d. 101.25mA
46. 2 resistors in series (R1 = 50 ohms; T1 =
350 degree K) and (R2 = 100 ohms; T2
= 450 degree K). Determine the total
noise voltage over a bandwidth of 120
kHz.
a. 543.4nV
b. 543.3nV
c. 643.4nV
d. 643.3nV
47. A certain company manufactures an AM
receiver with a noise temperature of 450
degree K. calculate the noise figure of
the receiver.
a. 4.0dB
b. 4.1dB
c. 4.2dB
d. 4.3dB
48. Calculate the noise temperature if the
input signal to noise ratio is 20 and the
output signal to noise ratio is 5.
a. 800K
b. 870K
c. 940K
d. 1010K
49. Calculate the bias current of the diode of
it produces 150 nA noise current over a
300 kHz bandwidth.
a. 234.1mA
b. 234.01mA
c. 234.2mA
d. 234.02mA
50. Noise voltage at the input of an amplifier
is 1 micro V. what is the signal voltage
of the input signal to noise ratio is 20
dB.
a. 10uV
b. 100uV
c. 1000uV
d. 10,000uV
51. A receiver has a noise power of 1 nW at

the input of the receiver. What would be
the signal power if the signal to noise
ratio is 40 dB?
a. 5uV
b. 10uV
c. 15uV
d. 20uV
52. What would be the noise voltage
generated of a 73 ohms resistor at room
temperature over the bandwidth of an
FM channel?
a. 452.nV
b. 472.nV
c. 492.nV
d. 512.nV
53. A 3 stage amplifier in cascade has the
following parameters. Stage 1 has a gain
of 5 and noise factor 2; stage 2 has a
gain of 8 and noise factor 4; stage 3 has
again of 15 and a noise factor of 6. Find
the overall noise factor of the system.
a. 2.725
b. 2.726
c. 2.727
d. 2.728
54. What is the noise power of a resistor at
room temperature with noise bandwidth
of 2.5 MHz?
a. 10x10-15w
b. 10x10-16w
c. 10x10-17w
d. 10x10-18w
55. What is the noise voltage given that R =
200 K ohms at a temperature of 27
degree Celsius and noise bandwidth of
54 MHz?
a. 423.uV
b. 424.uV
c. 425.uV
d. 426.uV
56. Calculate the noise voltage generated by
5 kilo ohms, 10 kilo ohms and 15 kilo
ohms, resistors connected in series.
Given that the temperature is 25 degree
Celsius, and noise bandwidth of 75
MHz.
a. 192.4uV
b. 193.4uV
c. 194.4uV
d. 195.4uV
57. Calculate the noise voltage generated by
3 kilo ohms, 10 kilo ohms, 21 kilo ohms,

resistors connected in parallel. Given
that the temperature is 17 degree
Celsius, and noise bandwidth of 15
MHz.
a. 21.3uV
b. 21.03uV
c. 22.3uV
d. 22.03uV
58. The shot noise current on a diode is 25
nA if 2.5 mA direct current is flowing
thru it. What is the effective noise
bandwidth of the diode?
a. 781.24khz
b. 781.25khz
c. 782.24khz
d. 782.25khz
59. A radio receiver uses a single parallel
tuned circuit, designed to resonate at
1605 kHz. The Q factor of the receiver is
50 and the channel bandwidth is limited
to 10 kHz. What is the noise voltage of
the receiver at the input at room
temperature if the capacitance of the
tuned circuit is 20 pF?
a. 0.9uV
b. 0.8uV
c. 0.7uV
d. 0.6.uV
60. A mixer with input resistance of 300
ohms has equivalent noise resistance of
100 ohms. What is the noise voltage at
the input when the effective noise
bandwidth is 25 kHz, the source voltage
is 2 micro V and with internal resistance
of 20 ohms?
a. 0.217uV
b. 0.218uV
c. 0.219uV
d. 0.220uV
61. In a TVRO circuit the antenna is
connected directly into the amplifier. To
match the input impedance of the
antenna and the 15 K ohms input
resistance of the amplifier a coupling
system is used with 10:1 ratio. The
amplifier has an equivalent noise
resistance of 150 kilo ohms. What is the
noise voltage seen at the amplifiers input
terminal? Given that the effective noise
bandwidth is 20 kHz at room
temperature.
a. 7.0uV

b. 7.1uV
c. 7.2uV
d. 7.3uV
62. A mixer with input resistance of 200
ohms has an equivalent noise resistance
of 100 ohms. What is the S/N at the
input if the effective noise bandwidth is
25 kHz, a source voltage of 2 micro V
and with internal resistance of 20 ohms?
a. 18.46dB
b. 18.47dB
c. 18.48dB
d. 18.49dB
63. What is the effective noise bandwidth of
a parallel tuned circuit with 5 kilo ohms
and 250 nF?
a. 800hz
b. 600hz
c. 400hz
d. 200hz
64. What is the effective noise bandwidth of
a parallel resonant circuit that has a Q
factor of 100 and resonant frequency of
5 MHz?
a. 78.54khz
b. 78.55khz
c. 78.56khz
d. 78.57khz
65. A parallel tuned circuit with 20 pF
tuning capacitor has an effective noise
bandwidth of 15 kHz. What is the noise
voltage across the circuit at room
temperature if the resonant frequency is
5 MHZ and a Q factor of 50?
a. 4.4uV
b. 4.04uV
c. 4.5uV
d. 4.05uV
66. In a TVRO circuit the antenna is
connected directly into the amplifier. To
match the input impedance of the
antenna and the 15 kilo ohms input
resistance of the amplifier a coupling
system is used. The amplifier has an
equivalent noise voltage of 7.1 micro V
at the input. Determine the antenna EMF
to produce an S/N of 30 dB if the
transformer coupling has a turn’s ratio of
10:1. Given that the effective noise
bandwidth is 20 kHz at room
temperature.
a. 44.8uV

b. 44.9uv
c. 44.10uV
d. 44.11uV
67. 4 telephone circuits are connected in
tandem. What is the overall S?N ratio of
each circuit has a S/N of 30 dB.
a. 12dB
b. 24dB
c. 36dB
d. 48dB
68. What is the output S/N ratio if the noise
factor is 20 and 25 dB input S/N ratio?
a. 6324.56
b. 6325.56
c. 6326.56
d. 6327.56
69. An AM receiver with RF amplifier,
mixer and an AF amplifier has an overall
noise figure of 60. The mixer has a noise
factor of 20 and power gain of 30, and
AF amplifier has noise factor and power
gain of 30 and 50 respectively. What is
the noise factor of the RF amplifier if
their power gain is 50?
a. 59.5
b. 59.6
c. 59.7
d. 59.8
70. A TVRO parabolic dish reflector mixer
stage has a noise figure of 20 dB and is
preceded by an LNB with a power gain
of 10 dB and an equivalent noise
temperature of 60 degree K. what is the
effective noise temperature at the input
of LNB?
a. 2921K
b. 2931K
c. 2941K
d. 2951K
71. In a microwave communications system,
determine the noise power in dBm for an
equivalent noise bandwidth of 10 MHz.
a. -103.98dBm
b. -103.97dBm
c. -103.96dBm
d. -103.95dBm

AMPLITUDE MODULATION
1. Determine the power saving in percent

2.

3.

4.

5.

6.

when the carrier is suppressed in an AM
signal modulated to 80%.
a. 75.76%
b. 75.77%
c. 75.78%
d. 75.79%
Find the percent of modulation of an AM
signal if 8 V signal carrier is modulated
by 3 different frequencies with
amplitude 1 V, 2 V and 3 V
a. 46.8%
b. 46.9%
c. 47.8%
d. 47.9%
An SSB transmitter radiates 100 W in a
75 ohms load. The carrier signal is
modulated by 2 tones, with frequencies 2
kHz and 3 kHz wit equal magnitude and
only the lower sideband is transmitted
with a suppressed carrier. What is the
peak voltage across the load?
a. 122.5V
b. 122.6V
c. 122.7V
d. 122.8V
An AM transmitter delivers 100 W
carrier powers, when the supplies deliver
10 A from a 15 V. what load impedance
is required by this amplifier in order for
it to deliver the rated power?
a. 1.24ohms
b. 1.25ohms
c. 1.26ohms
d. 1.27ohms
In AM, what is the sideband power
percentage assuming 100% modulation
and with carrier total power of 100 W
and 150 W respectively.
a. ½
b. 1/3
c. ¼
d. 2/3
An AM receiver uses a double tuned IF
transformer with coupling constant of
1.5 kc. the quality factor of the primary
and secondary winding is 60 and 30
respectively. What is the bandwidth of
the transformer if the IF is 455 MHz?
a. 16.38khz
b. 16.37khz
c. 16.36khz
d. 16.35khz

7. A measure of steepness of the skirts or
the skirt selectivity of a receiver is the
shape factor. What is the shape factor of
a receiver whose 60 dB bandwidth is 12
kHz and a 6 dB bandwidth of 3 kHz?
a. 2
b. 4
c. 6
d. 8
8. A 200 V without modulation and 250 V
with modulation is measured across a 50
ohms resistive load using true RMS
reading meter. What is the overall
efficiency without modulation if the
transmitter draws 1 kW of power from
the ac line?
a. 60%
b. 70%
c. 80%
d. 90%
9. An Am transmission of 3 kW is 100%
modulated. If it is transmitted as an SSB
signal, what would be the power
transmitted?
a. 500W
b. 1000W
c. 1500W
d. 2000W
10. The dc power supply of an SB
transmitter is 24 V. what is the average
power if the transmitter if on voice peaks
the current achieves a maximum of 9.3
A?
a. 74.4W
b. 74.5W
c. 74.6W
d. 74.7W
11. An AM receiver is tuned to broadcast
station at 600 kHz. Calculate the image
rejection in dB, assuming that the input
filter consists of one tuned circuit with a
Q of 40.
a. 37.57dB
b. 38.57dB
c. 39.57dB
d. 40.57dB
12. An SSB system transmits a peak
envelope power of 100 W into a 75
ohms load. The carrier signal is
modulated by two tones, with
frequencies 2 kHz and 3 kHz with equal
magnitude and only the lower sideband

is transmitted with a suppressed carrier.
Determine the average power into the
load.
a. 25W
b. 50W
c. 75W
d. 100W
13. In the SSB, determine the maximum
suppression of the unwanted sideband if
the deviation from a perfect 90 degree
phase shift is 5 degree?
a. 27.2dB
b. 27.3dB
c. 27.4dB
d. 27.5dB
14. An AM transmitter has an output power
of 100 W at no modulation with
efficiency of 60%. What will be the
output power with 97% modulation?
a. 147W
b. 148W
c. 149W
d. 150W
15. A standard AM receiver is tuned to a
station at 650 kHz. If the intermediate
frequency of the receiver is 455 kHz,
what is the image frequency?
a. 1550khz
b. 1560khz
c. 1570khz
d. 1580khz
16. An AM signal has a carrier frequency of
400 MHz and amplitude if 5 Vp. It is
modulated by a sinusoidal wave with
frequency of 2 kHz and peak amplitude
of 2 Vp. What are the lower and upper
sideband frequencies?
a. 300.002mhz
b. 400.002mhz
c. 500.002mhz
d. 600.002mhz
17. Given an audio power of 500 W which
will modulate an RF amplifier to 50%
modulation. Find the Dc power input.
a. 1000W
b. 2000W
c. 3000W
d. 4000W
18. A CB transmitter supplies a total power
of 120 W to an aerial. Suppose the
carrier is amplitude modulated to a depth
of 80%, how much power is wasted by

the carrier signal?
a. 31W
b. 61W
c. 91W
d. 121W
19. An IF transformer of a radio receiver
operates at 455 kHz. The primary circuit
has a Q of 50 and the secondary has a Q
of 40. Find the bandwidth using the
optimum coupling factor.
a. 15.288khz
b. 30.288khz
c. 45.288khz
d. 60.288khz
20. A spectrum analyzer is used ti measure
the magnitude of a certain signal with
respect to its frequency. Suppose the
equipment shows a carrier at 12 dBm,
with two sidebands 8 dB below the
carrier, what is the depth of modulation
of the signal?
a. 0.6
b. 0.7
c. 0.8
d. 0.9
21. Determine the modulation index of the
signal given the following parameters.
Emax = 10 Vp, Emin = 4 Vp.
a. 0.67
b. 0.68
c. 0.69
d. 0.70
22. A DSB-SC system must suppress the
carrier by 50 dB for its original value of
10 W. To what value must the carrier be
reduced?
a. 0
b. 0.1
c. 1
d. 2
23. An SSBSC signal is modulated with two
audio tones having frequencies of 1200
and 2700 Hz. The receiver is mistuned
so that the BFO is at 2.9993 MHz. What
will be the output frequencies of the
detector if the signal is LSB and the IF
of the receiver is 3 MHz?
a. 350hz
b. 700hz
c. 1050hz
d. 1400hz
24. A transistor has a power dissipation

rating of 30 W. assuming that the
transistor is the only element that
dissipated power in the circuit, calculate
the power an amplifier, using this
transistor, could deliver the load if it
operates as class A with an efficiency of
30%.
a. 12.86W
b. 12.85W
c. 12.84W
d. 12.83W
25. An Am signal supplies 150 W of carrier
power when it is modulated by a single
sine wave to a depth of 70%. Suppose
the total transmitted power increases by
10% when another sine wave
simultaneously amplitude modulates the
carrier, determine the modulation index
of the second sine wave.
a. 0.5
b. 0.4
c. 0.3
d. 0.2
26. What rms current must a wire carry to
deliver an average power if 500 W to a 4
ohm loudspeaker?
a. 9.18A
b. 10.18A
c. 11.18A
d. 12.18A
27. A superheterodyne receiver has an IF of
455 kHz and is experiencing image
channel interference on a frequency of
1570 kHz. The receiver is tuned to?
a. 200khz
b. 400khz
c. 600khz
d. 800khz
28. An AM transmitter with a 100 kW
carrier transmits 123 kW when two tones
modulated. Calculate the modulation
index of the second sine wave if the total
transmitted power is 110 when
modulated by a single sine wave.
a. 0.545
b. 0.546
c. 0.547
d. 0.548
29. When measuring the selectivity of a
receiver, you discover that a signal level
of 450 microV on an adjacent channel is
required to give the same output as 1

microV signal on the channel to which
the receiver is tuned. Calculate the
adjacent channel selectivity in dB.
a. 212dB
b. 159dB
c. 106dB
d. 53dB
30. A 300 V without modulation and 350 V
with modulation are measure across a 50
ohms resistive load using true RMS
reading meter. What is the amount of
power supplied in the transmitter when
modulated if the efficiency os 60%.
a. 4083.33W
b. 8083.33W
c. 12,083.33W
d. 16,083.33W
31. A transistor RF amplifier is required to
produce 15 W of carrier power when
operating from a 12 V supply. What is
the load impedance as seen from the
collector?
a. 16.8ohms
b. 12.8ohms
c. 8.8ohms
d. 4.8ohms
32. The output of a power amplifier if an
AM transmitter is 50 W with an
efficiency of 60% and is collector
modulated. How much audio power is
required to be supplied to this stage for
100% modulation?
a. 42.65W
b. 41.65W
c. 40.65W
d. 39.65W
33. The values of Vmax and Vmin as read
from an AM wave on an oscilloscope are
2.6 and 0.29 respectively. Determine the
percentage modulation.
a. 79.9%
b. 69.9%
c. 59.9%
d. 49.9%
34. A 3 stages RF amplifier of an AM
transmitter has an output power of 25
kW. What is the power supplied at the
second stage if the gain of the last stage
is 10 dB?
a. 2.5W
b. 5W
c. 7.5W

d. 10W
35. An AM transmitter supplies a 10 kW of
carrier power to a 50 ohms load. It
operates at a carrier frequency of 1.2
MHz and is 85% modulated by a 3 MHz
sine wave. Calculate the RMS voltage of
the signal.
a. 825V
b. 1650V
c. 2475V
d. 3300V
36. An AM signal has a modulation carrier
power if 10 watts. The percentage of
modulation is 90%. The total sideband
power is?
a. 4.05W
b. 4.06W
c. 4.07W
d. 4.08W
37. A class C amplifier has a carrier output
power of 100 W and an efficiency of
75%, when operating from a 20 V
supply. If the audio power is 25 W, what
is the impedance seen looking into the
power amplifier from the modulation
transformer secondary?
a. 8
b. 16
c. 24
d. 32
38. An AM signal has the following
characteristics; carrier frequency = 150
MHz; modulating frequency = 3 MHz;
peak carrier voltage = 40 V and peak
modulation voltage = 30 V. calculate the
peak voltage of the lower sideband
frequency.
a. 15V
b. 30V
c. 45V
d. 60V
39. An AM signal has a carrier frequency of
3 MHz and amplitude of 3 Vpeak. What
is the amplitude of the sidebands if the
modulation index is 0.6?
a. 0.9V
b. 1.0V
c. 1.1V
d. 1.2V
40. An Am transmitter has an output power
of 30 kW. If the last stage of the RF
amplifier has a gain of 20 dB and an

efficiency of 75%, how much current
does the amplifier draw from a 125 V
supply?
a. 160mA
b. 320mA
c. 480mA
d. 640mA
41. A receiver has two uncoupled tuned
circuits before the mixer, each with a Q
of 75. The signal frequency is 100.1
MHz and IF is 10.7 MHz. if the local
oscillator uses high side injection, what
is the image rejection ratio on dB?
a. 29.33dB
b. 29.66dB
c. 29.99dB
d. 30.33dB
42. An amplitude signal has a maximum
positive envelope voltage of 14 V and a
minimum of 2 V. what is the total
transmitted power if the carrier power is
10 kW and suppressing one of the
sidebands?
a. 10.41kW
b. 11.41kW
c. 12.41kW
d. 13.41kW
43. The average collector current of a
transistor RF amplifier operating class C
is 250 mA. If the efficiency of the
amplifier is 50% and operating at 50 V
supply, how much audio power is
needed for 100% modulation?
a. 3.25W
b. 6.25W
c. 9.25W
d. 12.25W
44. A radio transmitter has to operate at a
temperature of 34 degrees Celsius. If its
signal is derived from a crystal oscillator
with a temperature coefficient of plus 1
pm per degree centigrade and it
transmits at exactly 150 MHz at 20
degrees centigrade, find the transmitting
frequency.
a. 150.0021 MHz
b. 160.0021 MHz
c. 170.0021 MHz
d. 180.0021 MHz
45. A standard AM radio can receive signal
from 565 – 1650 kHz. If an AM receiver
is tuned at 854 kHz, what is the

frequency of the image signal?
a. 1564 kHz
b. 2356 kHz
c. 1764 kHz
d. 1587 kHz
46. An AM transmitter is modulated by two
sine waves at 1.5 kHz and 2.5 kHz, with
modulations of 20% and 80%
respectively. Calculate the effective
modulation index.
a. 0.26
b. 0.45
c. 0.84
d. 0.82
47. Calculate the power in one sideband of
an AM signal whose carrier power is 50
watts. The unmodulated current is 2 A
while the modulated current is 2.4 A
a. 15W
b. 14W
c. 16W
d. 11 W
48. An AM broadcast transmitter has a
sideband power output of 5 kW.
Calculate the carrier power if the
modulation index is 0.5.
a. 45kW
b. 40kW
c. 56kW
d. 52kW
49. If a transmitters supplies 8 kW to the
antenna when it is unmodulated,
determine the total radiated power when
modulated at 30%.
a. 8.36kW
b. 5.23kW
c. 8.21kW
d. 2.56kW
50. An LC tuned circuit is used to detect an
AM radio frequency band ranging from
535 to 1695 kHz. What us the bandwidth
at 1695, if its bandwidth is 12 kHz at
535 kHz?
a. 45.65 kHz
b. 34.21 kHz
c. 21.36 kHz
d. 56.23kHz
51. A class C collector modulated amplifier
has an output carrier power of 100 W
and an efficiency of 80%. How much
audio power must be supplied to the
amplifier for 100% modulation?

a. 62.5W
b. 26.3W
c. 59.2W
d. 12.2W
52. What is the range of the upper sideband
of an amplitude modulated signal whose
carrier is 2.5 MHz and the intelligence
component is 50 Hz to 20 kHz?
a. 5.23 MHz
b. 2.52 MHz
c. 23.2 MHz
d. 1.23MHz
53. An SSB transmitter generates USB
signal with Vpeak = 10 V. determine the
peak envelope power across a 50 ohms
load resistance.
a. 1W
b. 2W
c. 3W
d. 7W
54. CB radio wave signal is developed using
a full carrier DSB-AM. For high fidelity,
the system requires a frequency response
from 50 Hz to 15 kHz. What bandwidth
would it used to satisfy the requirement?
a. 35 kHz
b. 32 kHz
c. 30 kHz
d. 31kHz
55. The frequency response of an audio
signal that amplitude modulates the
carrier signal is 6 dB down at 2.5 kHz
deom its level at 1.25 kHz. What will be
the modulation index due to a 2.5 kHz
signal with the same signal at the input,
if a 1.25 kHz signal modulates the
carrier to 85%?
a. 0.236
b. 0.425
c. 12.033
d. 0.569
56. In an AM transmitter, the final RF power
amplifier is high level modulated. The
dc supply voltage is 48 V with a total
current of 3.5 A. how much AF power is
required for 100% modulation?
a. 48W
b. 84W
c. 56W
d. 23W
57. An AM transmitter supplies of 20 kW of
carrier power to a 75 ohms load.

Calculate the maximum instantaneous
voltage the will be developed across the
load.
a. 1546V
b. 5642V
c. 1722V
d. 1732V
58. What is the peak envelope power of a
SSB transmitter that produces a peak to
peak voltage of 178 V across a 75 ohms
antenna load?
a. 56.2W
b. 52.8W
c. 62.5W
d. 63.2W
59. What oscillator frequency is needed to
heterodyne 626 kHZ up to 3.58 MHz?
a. 4.206 MHz
b. 2.036 MHz
c. 5.021 MHz
d. 3.021MHz
60. An SSB system requires 100 W of
transmitted power fir reliable
transmission. How much power is
needed if DSBFC is used instead of
SSB?
a. 500W
b. 600W
c. 700W
d. 800W
61. A carrier signal simultaneously
modulated by two sine waves at 1.5 kHz
and 0.8 kHz with modulation index 0.3
and 0.6 respectively. Calculate the total
modulation index.
a. 0.32
b. 0.67
c. 0.25
d. 0.87
62. A CB transmitter supplies a total power
of 200 W to an aerial. Supposed the
carrier is modulated to a depth of 70%
using DSBFC AM. By how much will
the signal to noise ratio be improved if
the modulation technique used is SSB
instead of DSBFC AM?
a. 10dB
b. 11dB
c. 12dB
d. 13dB
63. What is the power in one sideband of an
AM signal whose carrier is 300 W, with

80% modulation?
a. 45W
b. 46W
c. 48W
d. 12W
64. A filter type SSB generator uses an ideal
band pass filter with a center frequency
of 5 MHz and a bandwidth of 2.7 kHz.
What frequency should be used for the
carrier oscillator if the generator is to
produce a USB signal with a baseband
frequency response having a lower limit
of 280 Hz?
a. 4.99837 MHz
b. 5.23154 MHz
c. 3.21548 MHz
d. 7.26456 MHz
65. What will be the total sideband power of
the AM transmitting station whose
carrier power is 1200 W and a
modulation of 95%?
a. 125.2W
b. 541.5W
c. 154.2W
d. 985.02W
66. An AM signal has a carrier frequency of
115 MHz modulated by a single sine
wave. The modulated signal developed a
maximum positive envelope voltage of 8
V and a minimum of 2 V. what is the
magnitude of the peak voltage of the
unmodulated carrier?
a. 1V
b. 2V
c. 3V
d. 5V
67. A transistor RF power amplifier
operating class C is designed to produce
40 W output with a supply voltage of 60
V. if the efficiency is 70% what is the
average collector current?
a. 952.4mA
b. 895.3mA
c. 784.6mA
d. 896.2mA
68. A radio technician measure 350 V
without modulation and 400 V with
modulation at the output of an AM
transmitter with 50 ohms resistive load
using true RMS reading meter. What is
the modulation index of the signal?
a. 0.56

b. 0.78
c. 0.65
d. 0.98
69. A certain amateur radio station is tuned a
t200 kHz with an image frequency at
460 kHz. Determine the intermediate
frequency of the receiver.
a. 150 kHz
b. 140 kHz
c. 130 kHz
d. 160kHz
70. What is the local oscillator frequency
range in commercial AM broadcast if it
is equal to 455 kHz?
a. 2055 kHz
b. 2065 kHz
c. 2045 kHz
d. 2068 kHz
71. A super heterodyne receiver tunes at the
frequency range from 25 to 50 MHz.
what is the IF frequency of the receiver
if the range of the local oscillator is 10
MHz to 35 MHz.
a. 16 MHz
b. 15 MHz
c. 14 MHz
d. 13MHz
72. A receiver has a sensitivity of 0.5 micro
V and a blocking dynamic range of 70
dB. What is the strongest signal that can
be present along with a 0.5 micro V
signal without blocking taking place?
a. 1.56mV
b. 1.53mV
c. 1.54mV
d. 1.58mV
73. A receiver can handle a maximum signal
level of 100 mV without overloading is
100 dB, what is the sensitivity of the
receiver?
a. 1uV
b. 2uV
c. 3uV
d. 4uV
74. What is the shape factor of the filter if
10 kHz bandwidth is measured below 6
dB and 30 kHz below 60 dB?
a. 3
b. 4
c. 5
d. 6
75. An AM transmitter uses high level

modulation. The RF power amplifier
draws 12 A from a 22 V supply, putting
out a carrier power of 140 watts. What
impedance would be seen at the
modulation transformer secondary?
a. 1.23 ohms
b. 1.83 ohms
c. 1.56 ohms
d. 1.82ohms
76. Calculate the highest and lowest
frequencies for a sub carrier signal at
629 kHz with bandwidth of + or – 500
kHz.
a. 126 kHz
b. 125 kHz
c. 124 kHz
d. 129 kHz
77. A tuned transformer has a kopt = 1.5 kc
operating at a frequency of 455 kHz. The
primary of Q is 75. What is the band
width of the tuned transformer?
a. 13.3 kHz
b. 14.5 kHz
c. 12.5 kHz
d. 16.3 kHz
78. A 12 W of power is being supplied in the
modulating amplifier for 100%
modulation. What is the carrier power
output of the radio transmitter at an
efficiency of 75%?
a. 15W
b. 18W
c. 19W
d. 20W
79. A transmitted signal 5 meters in
wavelength is received by an antenna
coil having a 50 ohm resistance and a
0.01 H inductance. What is the
capacitance of the tuner shunting the
antenna coil at this point?
a. 0.704fF
b. 0.705fF
c. 0.506fF
d. 0.404fF
80. Assuming 100% modulation, what
would be the transmitted power in the
upper sideband of an AM signal if the
carrier power is 1000 watts?
a. 150W
b. 250W
c. 650W
d. 350W

81. A certain radio transmitter has a carrier
power output of 150 W and an efficiency
of 80%. How much power is dissipated
in the transistor with 80% modulation?
a. 50W
b. 56W
c. 49.3W
d. 49.5W
82. An AM transmitter uses a high level
modulation. The RF power amplifier
runs from a 12 V source, putting out a
carrier power of 85 W, with an efficiency
of 85%, what load impedance is required
in order for it to deliver the rated power?
a. 0.85
b. 0.84
c. 0.86
d. 0.89
83. An AM mobile transmitter supplies 5
kW of carrier power to a 50 ohms load.
The carrier signal is modulated by a 3
kHz sine wave to a depth of 80% at a
frequency of 10 MHz. determine the
sideband power.
a. 1600W
b. 1200W
c. 1500W
d. 1800W
84. If the percentage modulation of an AM
amplifier is 88% and the modulating
signal is 1 V, the carrier has amplitude
of?
a. 1.12V
b. 1.13V
c. 1.15V
d. 1.14V
85. An AM receiver uses a low side
injection for the locas oscillator, with an
IF of 455 kHz. The local oscillator is
operating at 2.1 MHz. What is th e IF of
the signal?
a. 1.645 MHz
b. 1.256 MHz
c. 1.459 MHz
d. 1.256MHz
86. An AM signal has the following
characteristics, the carrier frequency is
150 MHz, the modulating signal
frequency is 3 kHz, the carrier voltage is
60 V, and where the modulating signal
voltage is 30 V. find the peak voltage of
the lower side frequency.

a. 16V
b. 15V
c. 12V
d. 13V
87. The average collector current of a
transistor RF amplifier operating class C
is 250 mA. If the efficiency of the
amplifier is 60% and operating at 50 V
supply, what is the power output of the
amplifier?
a. 5.5W
b. 6.5W
c. 7.5W
d. 8.5W
88. An AM transmitter is rated 100 W at
100% modulation. How much power
required for the carrier?
a. 66.67W
b. 55.57W
c. 44.57W
d. 99.67W
89. An AM mobile transmitter supplies 5
kW of carrier power to a 50 ohms load.
The carrier signal is modulated by a 3
kHz sine wave to a depth of 80% at a
frequency of 10 MHz. Determine the
peak voltage of the modulating signal.
a. 548.2V
b. 548.7V
c. 565.7V
d. 585.1V
90. An AM signal has a carrier frequency of
3 MHz and amplitude of 2 Vpeak. What
is the sideband frequency if the
bandwidth of the AM signal is 20 kHz?
a. 3.02 MHz
b. 5.23 MHz
c. 1.25 MHz
d. 6.31 MHz
91. At 100% modulation, the sum of the
effective voltages in both sidebands is
equal to?
a. 50.2%
b. 60.2%
c. 70.7%
d. 80.5%
92. An AM transmitter transmits 40 kW with
no modulation. How much power will it
transmit if modulation index increases
by 80%?
a. 52.8kW
b. 56.2kW

c. 53.8kW
d. 54.6kW
93. 100% modulation in AM means a
corresponding increase in total power
by?
a. 60%
b. 70%
c. 50%
d. 80%
94. An AM transmitter delivers 100 W
carrier powers, when the supplies deliver
8 A from a 15 V. how much power must
be supplied by the modulating amplifier
85% modulation?
a. 45W
b. 23.5W
c. 12.4W
d. 43.35W
95. A collector modulated class C amplifier
has a carrier output power of 100 W, and
with an efficiency of 60%, calculate the
transistor power dissipation, assuming
that all the power dissipation that occurs
comes from the transistor.
a. 66.67W
b. 65.63W
c. 689.23W
d. 68.32W
96. An AM transmitter transmits 40 kW with
no modulation. How much power will it
transmit if modulation index is 80%?
a. 52.8kW
b. 52.3kW
c. 52.4kW
d. 52.9kW
97. A filter type SSB generator uses an ideal
band pass filter wit h a center frequency
of 5 MHz and a bandwidth of 2.7 kHz.
What frequency should be used for the
carrier oscillator if the generator is to
produce a USB signal with a baseband
frequency response having a lower limit
of 280 Hz?
a. 4552.35 kHz
b. 4998.37 kHz
c. 4557.65 kHz
d. 4875.56kHz
98. The voice signal is modulated using a
SSBSC technique with two audio tones
having frequencies of 700 and 1200 Hz.
The modulated signal has a suppressed
carrier frequency in the IF receiver of 3

MHz. the receiver is mistuned causes the
BFO to generate 2.995 MHz. Determine
the output frequencies of the
demodulator if the signal is USB.
a. 200 and 700 Hz
b. 300 and 800 Hz
c. 400 and 900 Hz
d. 500 and 1000Hz
99. 3 audio waves with 100, 200 and 300 V
amplitude respectively, simultaneously
modulate a 450 V carrier. What is the
total percent of modulation of the AM
wave?
a. 86%
b. 85%
c. 84%
d. 83%
100. An AM broadcast transmitter output
power is 15 kW if the carrier is
simultaneously modulated with another
sine wave at 50% modulation. What is
the modulation index of the other sine
wave if the carrier power is 12 kW?
a. 0.5
b. 0.2
c. 0.6
d. 0.4
101. What is the maximum suppression
for a phase error of 3 degree?
a. 31.64dB
b. 31.65dB
c. 31.62dB
d. 31.52dB

FREQUENCY MODULATION
1. Using Carson’s rule, what is the
bandwidth of an FM signal with 5

kHz maximum frequency deviation
and 2.5 kHz maximum modulating
frequency?
a. 14 kHz
b. 16 kHz
c. 18 kHz
d. 15kHz
2. Calculate the maximum bandwidth
required of a standard FM broadcast
station.
a. 156 kHz
b. 180 kHz
c. 154 kHz
d. 160 kHz
3. The operating frequency of an FM
transmitter is 168.96 MHz. calculate
the frequency of the carrier crystal
oscillator if it uses three frequency
multipliers – a doubler, a tripler and
a quadrupler.
a. 7.04 MHz
b. 7.05 MHz
c. 7.06 MHz
d. 7.07MHz
4. What frequency deviation is caused
by noise in an FM receiver which
has an input S/N of 2.8 and the
modulating frequency of 1.5 kHz?
a. 569.2Hz
b. 587.3Hz
c. 547.8Hz
d. 569.2Hz
5. In GM broadcasting, what is the
carrier frequency in MHz of a station
with a channel number of 285?
a. 104.9 MHz
b. 104 MHz
c. 8 MHz
d. 104.5 MHz
6. In FM broadcasting, what is the
channel number of the station with a
given carrier of 99.1 MHz?
a. 254
b. 259
c. 258
d. 256
7. What is the rms output voltage of a
PLL FM detector if it uses VCO with
proportionality constant of 299
kHz/V and if it receives an FM
signal with a deviation of 65 kHz

sine-wave modulated?
a. 0.25V
b. 0.23V
c. 0.24V
d. 0.26V
8. A phase-locked loop has a VCO with
free-running frequency of 19 MHz.
as the frequency of the reference
input is gradually raised from zero,
the loop locks at 8 MHz and comes
out of lock again at 14 MHz.
determine the lock range.
a. 5 MHz
b. 6 MHz
c. 8 MHz
d. 9 MHz
9. A phase modulator has kp = 2rad/V.
what rms voltage of a sine wave
would cause a peak phase deviation
of 30 degrees?
a. 0.184V
b. 0.156V
c. 0.187V
d. 0.185V
10. A system uses a deviation of 100
kHz and a modulating frequency of
15 kHz. What is the approximate
bandwidth?
a. 235 kHz
b. 234 kHz
c. 230 kHz
d. 236kHz
11. A phase-locked loop has a VCO with
a free-running frequency of 14 MHz.
as the frequency of the reference
input is gradually raised from zero.
The loop locks at 12 MHz and comes
out of lock again at 18 MHz.
calculate the capture range.
a. 4 MHz
b. 5 MHz
c. 6 MHz
d. 7MHz
12. What is the frequency swing of an
FM broadcast transmitter when
modulated 80%?
a. 60 kHz
b. 62 kHz
c. 63 kHz
d. 64kHz
13. Determine the modulation index of a
standard FM broadcast having a

hypothetical maximum carrier
frequency deviation of +- 12 kHz
and a maximum modulating
frequency of 4 kHz.
a. 5
b. 4
c. 3
d. 2
14. What is the modulation index of an
FM transmitter whose frequency
deviation is 50 kHz, while its audio
frequency is 10 kHz?
a. 8
b. 6
c. 7
d. 5
15. The carrier swing necessary to
provide 80% modulation in the FM
broadcasting band is ____?
a. 120 kHz
b. 130 kHz
c. 140 kHz
d. 150 kHz
16. An FM signal has a center frequency
of 100 MHz but is swinging between
100.01 MHz and 99.999 MHz at a
rate of 100 times per second, what is
the modulation index of the signal?
a. 110
b. 100
c. 90
d. 80
17. If the frequency fed to the preamplifier of a basic transmitter with
multipliers is composed of a pair of
triples and a doublers multipliers is
198 MHz. what frequency should the

oscillator operate?
a. 10 MHz
b. 11 MHz
c. 12 MHz
d. 13MHz
18. For commercial FM broadcasting the
maximum permissible range in
modulation index is 5 – 2500. What
is the maximum bandwidth needed
for this system?
a. 180 kHz
b. 190 kHz
c. 200 kHz
d. 210kHz
19. A portable radio transmitter has to
operate at temperatures from – 5
degrees to 35 degrees C. if its signal
is derived from a crystal oscillator
with a temperature coefficient of +1
ppm per degree centigrade, and it
transmit at exactly 145 MHz at 20
degrees C, find the transmitting
frequency at 35 degrees C.
a. 145.002175 MHz
b. 145.002174 MHz
c. 145.002176 MHz
d. 145.002154MHz
20. What FM channel is 107.5 MHz
carrier?
a. 299
b. 298
c. 297
d. 296
21. The instantaneous value of the
modulating signal to and FM

modulator is -2V, sensitivity kf = 25

modulating frequency of 300 Hz.

kHz/V and operating at a carrier

What is the maximum frequency

frequency of 88 MHz. determine the

deviation of the system?

output frequency of the modulator.

a. 315 Hz

a. 87.59 MHz

b. 314 Hz

b. 95.32 MHz

c. 316 Hz

c. 87.95 MHz

d. 317Hz

d. 84.65 MHz
22. Calculate the frequency deviation of

26. An FM communication system has a
sensitivity of kf = 3 kHz/V. how

an Fm modulator that has kf = 20

much phase deviation does it

kHz/V and operates at a carrier

produces with a sine wave input of 3

frequency of 99.1 MHz modulated

V peak at a frequency of 2 kHz?

by a 2.5 Vrms sine wave.

a. 4.2rad

a. 70.5 kHz

b. 4.5rad

b. 70.6 kHz

c. 4.3rad

c. 70.7 kHz

d. 4.8rad

d. 70.8kHz
23. Find the deviation ratio of an FM

27. An FM broadcast transmitter rated
output power is 5 W. what is the

broadcast transmitter if the frequency

peak voltage developed across a 50

of the modulating signal varies from

ohms resistive load?

30 Hz to 20 kHz.

a. 22.34V

a. 3.75

b. 22.35V

b. 3.74

c. 22.36V

c. 3.73

d. 22.37V

d. 3.72
24. The output signal of a PM

28. An FM system has a modulation
index of 3 and its corresponding

demodulator is 0.54 V. what is the

Bessel coefficient; Jo = -0.26; J1 =

sensitivity of the demodulator if the

0.34; J2 = 0.49; J3 = 0.31. Find the

phase deviation is 30o?

RMS carrier voltage if the total

a. 0.99rad/V

power is 5 W. developed across a 50

b. 0.98rad/V

ohms resistive load.

c. 0.97rad/V

a. 4.16V

d. 0.96rad/V

b. 4.11V

25. A PM transmitter produces a
maximum phase shift of r/3 rad for a

c. 4.23V
d. 4.56V

29. Suppose the total power of an FM

a. 2

signal is 7W. What is the power of

b. 3

the second sideband if the

c. 5

modulation index is 3? J0 = -0.26; J1

d. 4

= 0.34; J2 = 0.49; J3 = 0.31.

33. An FM signal with modulation index

a. 3.4W

of 4 and modulating frequency of 8

b. 3.5W

kHz. What is the frequency deviation

c. 3.6W

of the signal?

d. 3.2W

a. 36 kHz

30. An FM broadcast transmitter has a

b. 35 kHz

deviation of 25 kHz and a

c. 31 kHz

modulating frequency of 8 kHz.

d. 32kHz

Calculate the power that is

34. A certain FM modulator has kf = 25

unaccounted, if the total power PT is

kHz/V. Suppose the peak amplitude

10 W. J0 = -0.26; J1 = 0.34; J2 = 0.49;

of the modulating signal is 3 V at a

J3 = 0.31.

frequency of 3 kHz, determine the

a. 0.289W

modulation index of the signal.

b. 0.288W

a. 25

c. 0.283W

b. 26

d. 0.254W

c. 27

31. A certain FM station transmitted a
modulating frequency of 25 kHz and

d. 28
35. The output frequency of the

a frequency deviation of 75 kHz.

modulator increases by 50 kHz.

What is the approximate signal-to-

What is the dc voltage applied to the

noise ratio at the detector output if

FM modulator, if the deviation

the signal-to-noise ratio at the input

sensitivity is 25 kHz/V?

to the receiver detector is 20 dB?

a. 5V

a. 34dB

b. 4V

b. 35dB

c. 3V

c. 36dB

d. 2V

d. 37dB
32. An FM broadcast station transmits a

36. The maximum instantaneous
frequency of the modulated signal is

3 kHz test tone, and a frequency

95.05 MHz. if a 5 kHz signal

deviation of 15 kHz. Determine the

modulates a 95 MHz carrier,

modulation index.

calculate the modulation index of the

signal.

b. 300mV

a. 10

c. 220mV

b. 1

d. 100mV

c. 11
d. 12

40. With a maximum frequency
deviation of 75 kHz, what is the

37. A PM signal has a RMS signal of 3

maximum phase deviation that can

V at a frequency of 3 kHz. If the

be present in an FM radio broadcast

modulation index of the signal is 15,

signal, assuming it transmits a

determine the sensitivity of the

baseband frequency of 50 Hz to 20

modulator.

kHz?

a. 3.54rad/V

a. 1560rad

b. 3.53rad/V

b. 1500rad

c. 3.55rad/V

c. 1540rad

d. 3.52rad/V

d. 1546rad

38. The modulation index of the PM

41. The phase shift of a phase modulated

signal is 2. If a modulating signal

signal is 86 degree. What is the

that has amplitude of 50 mV at a

modulation index of the said signal?

frequency of 3 kHz phase modulates

a. 1.2

a 90 kHz carrier signal, what would

b. 1.5

be the new modulation index of the

c. 1.3

signal? Assume that the amplitude of

d. 1.6

the modulating signal is increased by

42. Determine the modulation index of

50%.

an FM signal, given that the

a. 5

modulating frequency is 25 kHz and

b. 4

frequency deviation of 75 kHz.

c. 3

a. 3

d. 2

b. 5

39. A sine wave of frequency 15 kHz
modulates a carrier at 101.1 MHz.
the peak frequency deviation is 75

c. 4
d. 6
43. Suppose a certain FM signal uses a

kHz. Determine the peak amplitude

frequency deviation of 100 kHz and

of the modulating signal if the

a modulating index of 5. Calculate

sensitivity of the modulator is 50

the band width using Carsons rule.

rad/V.

a. 250kHz

a. 40mV

b. 240kHz

c. 260kHz

only the carrier and the first two sets

d. 230kHz

of sidebands. If the total power of the

44. An FM station transmits 100 W of

signal is 10 W, deviation is 25 kHz,

power. If the modulation index of the

and the modulation index is 10, how

signal is 7, how much power is

much power is transmitted at the

transmitted at the carrier frequency if

carrier frequency?

Jo = 0.4?

a. 485mW

a. 16W

b. 484mW

b. 17W

c. 456mW

c. 18W

d. 481mW

d. 19W
45. A 50 ohms dummy load is used to

48. The calculated bandwidth using
Carsons rule is 40 kHz if the

test a certain FM station. Suppose

modulating frequency of the signal is

the measured power is 12.5 W, what

5 kHz. Using the same signal, what

is the voltage level of the second

is the bandwidth if sidebands with

sideband if a frequency of 5 kHz test

more than 1% of the signal voltage

tone is used and a 10 kHz frequency

are considered?

deviation?

a. 61 kHz

a. 8.45Vrms

b. 62 kHz

b. 8.56Vrms

c. 60 kHz

c. 8.75Vrms

d. 63kHz

d. 8.26Vrms
46. An FM receiver can sufficiently

49. An FM transmitter operates with a
carrier power of 10 W. what is the

receives only the carrier and the first

total signal power if the modulation

two sets of side bands. If the total

index of the signal is 5?

power of the signal is 20 W,

a. 308W

deviation of 25 kHz, and a

b. 309W

modulation index of 10, what is the

c. 310W

percentage of the total signal power

d. 311W

will it receive?

50. The maximum phase deviation given

a. 96.62%

to the signal by the noise voltage is

b. 96.65%

0.01radian. What is the signal to

c. 96.68%

noise ratio at the detectors input?

d. 96.56%

a. 41dB

47. An FM receiver sufficiently receives

b. 42dB

c. 43dB

signal that is modulated to 10 kHz

d. 40dB

deviation by a sine wave?

51. An FM receiver detects a 100 mV

a. 5 kHz/V

signal. A spurious signal is also

b. 6 kHz/V

detected by the receiver that resulted

c. 7 kHz/V

to an S/N of 40 dB at the detectors

d. 8 kHz/V

output. Determine the minimum S/N

55. An FM receiver uses a tuned

ratio at the detectors output if the

transformer operating at 10.7 MHz.

modulating frequency is 2 kHz and

what is the bandwidth using the

frequency deviation of 50 kHz.

optimum coupling factor if the

a. 12dB

primary circuit has a Q of 50 and the

b. 13dB

secondary has Q of 35?

c. 14dB

a. 383.6 kHz

d. 15dB

b. 383.7 kHz

52. An FM receiver is tuned at 99.1
MHz. what is the IF rejection ratio if
the receiver consists of a single tuned

c. 383.8 kHz
d. 383.9 kHz
56. An FM super heterodyne receiver is

circuit with Q of 45?

tuned to a frequency of 88 MHz.

a. 23dB

what is the local oscillator frequency

b. 24dB

if low side injection is used at the

c. 25dB

mixer?

d. 26dB

a. 77.3 MHz

53. An FM detector receives an FM

b. 77.4 MHz

signal with a deviation of 15 kHz.

c. 77.5 MHz

What is the peak to peak output

d. 77.6MHz

voltage of the detector if its
sensitivity is 75 microV/Hz?
a. 2.25V
b. 2.26V
c. 2.27V
d. 2.28V
54. An FM receiver uses PLL to detect
the signal. What is the sensitivity of
the VCO in the PLL if the output of
the detector is 1.25 Vp from an FM

MULTIPLE

CHOICE
QUESTIONS
in
COMPREHENSIVE
REVIEWER IN
COMMUNICATIO
NS ENGINEERING
Philander U. Lomboy, ECE
Benedetto D. Villanueva, ECE

Encoded by:
TOL
ENT
INO,
Naza
rio
M. II
VIL
LAF
LOR
ES,
Cind
y A.
dB/NOISE
Multiple choice. Encircle the letter which
corresponds to your answer.

1. A current change that is equal to twice its
original value will correspond to a change of
a. 3 dB
b. 9 dB
c. 10 dB
d. 6 dB
2. What does a power difference of -3dB
mean?
a. A loss of one third of the power
b. A loss of one-half of the power
c. A loss of 3 watts of power
d. No significant change
3. A gain of 60 dB is the same as a gain of
a. 10 volts/volt
b. 100 volts/volt
c. 1000 volts/volt
d. 10,000 volts/volt
4. ______ is mathematically equal to the
logarithm to the base ten of the power ratio
P1 over P2.
a. bel
b. dB
c. bel/10
d. dB/2
5. Noise that is produced by the active
components within the receiver.
a. Thermal
b. External
c. Internal
d. White
6. Noise due to random variation in the arrival
of charge carriers at the output electrode of
an active device
a. Shot
b. Impulse
c. Thermal
d. Dynamic
7. A network has a loss of 20 dB. What power
ratio corresponds to this loss
a. 0.01
b. 0.1
c. 10
d. 100
8. A receiver connected to an antenna whose
resistance is 60 ohms has an equivalent
noise resistance of 40 ohms. Calculate the
receiver’s noise figure in decibels and its
equivalent noise temperature.
a. 1.67 & 194°K
b. 2.23 & 194°K
c. 1.67 & 174°K
d. 2.23 & 194°K

9. _____ Noise is the most prevalent noise
found in urban areas and is normally caused
by the arc discharge from automobile or
aircraft ignition systems, induction motors,
switching gears, high voltage lines and the
like.
a. Industrial
b. Johnson
c. Flicker
d. Mixer
10. The noise figure of a totally noiseless device
is
a. Unity
b. Infinity
c. Zero
d. 100
11. Indicate the noise whose source is in a
category different from that of the other
three.
a. Solar
b. Cosmic
c. Atmospheric
d. Galactic
12. The ratio(in dB) of the power of a signal at
point to the power of the same signal at the
reference point.
a. Transmission Level Point
b. Noise Figure
c. S/N Ratio
d. Neper
13. A network has a power gain of -3dB. If the
input power is 100 watts, the output power
is
a. 50 watts
b. 55 watts
c. 60 watts
d. 62 watts
14. Which of the following types of noise
becomes of great importance at high
frequencies?
a. Shot
b. Random
c. Impulse
d. Transmit time
15. The input current of a network is 190 uA
and the output is 1.3 uA. The loss in
decibels is
a. 20.2
b. 21.6
c. 28.6
d. 43.3

16. If a network connected in series have a gain
of -0.5 dB, -0.3dB, -2dB and 6.8dB, the
overall gain is
a. 2 dB
b. -2dB
c. 4 dB
d. -4dB
17. What is the gain, in dB, if the output to input
ratio is 1000.
a. 20
b. 30
c. 40
d. 10
18. The following characteristics of noise exept
a. Unwanted energy
b. Predictable in character
c. Present in the channel
d. Due to any cause
19. The equivalent noise temperature of the
amplifier is 25 °K what is the noise figure?
a. 10.86
b. 1.086
c. 0.1086
d. 1.86
20. A receiver connected to an antenna whose
resistance is 50 ohms has an equivalent
noise resistance of 30 ohms. What is the
receiver’s noise temperature?
a. 464°K
b. 754°K
c. 400°K
d. 174°K
21. A theoretical antenna has a gain of 1dB. Its
gain in nepers is
a. 8.686
b. 0.1151
c. 6.868
d. 0.5111
22. What is the equivalent output of a circuit in
dBm, if it has an output of 10 watts?
a. 10 dBm
b. 30dBm
c. 20dBm
d. 40dBm
23. An amplifier with an input resistance of
1000 ohms is operating over a 4 MHz
bandwidth. Calculate the rms voltage if the
amplifier is operating at 27 °C.
a. 8.14 nV
b. 8.14 uV

c. 6.6 nV
d. 6.6 uV
24. The value of a resistor creating thermal
noise is doubled. The noise power generated
is therefore
a. Halved
b. Quadrupled
c. Doubled
d. Unchanged
25. One of the following is not a useful quantity
for comparing the noise performance of
receivers.
a. Input noise voltage
b. Equivalent noise resistance
c. Noise temperature
d. Noise figure
26. Any unwanted form of energy that tends to
interfere with the wanted signal is called
a. Noise
b. Spectrum
c. Radiation
d. Absorption
27. The correct symbol for decibel is
a. DB
b. dB
c. Db
d. db
28. _____ is the noise created outside the
receiver.
a. Internal
b. External
c. Shot
d. Industrial
29. _____ is the noise created by man.
a. Solar
b. Industrial
c. Extraterrestrial
d. Galactic
30. A voltage change that is equal to twice its
original value correspond to a change of
a. 3dB
b. 6dB
c. 9dB
d. 10dB
31. Indicate the voltage level in dB with
reference to one volt. This unit is used in
video or TV measurement
a. dBW
b. dBk
c. dBm

d. dBV
32. which of the following is not an actual
amount of power?
a. dB
b. dBm
c. dBw
d. dBk
33. In noise analysis, the reference temperature
is
a. 75 K
b. 250 K
c. 290 K
d. 300 K
34. Noise from distant panels, stars, galaxies
and other celestial objects are called
a. Cosmic
b. Extraterrestrial
c. Galactic
d. Black body
35. Indicate which one of the following types of
noise does not occur in transistors
a. Shot noise
b. Flicker noise
c. Partition noise
d. Resistance noise

36. Which of the following is not a source of
space noise
a. Sun
b. Star
c. Lightning
d. Black body
37. Noise that is due to the random and rapid
motion of the charge carriers inside a
resistive component.
a. Johnson
b. Thermal Agitation
c. White
d. All of the above
38. Indicate the false statement. The square of
the thermal noise voltage generated by a
resistor is proportional to
a. Its resistance
b. Its temperature
c. Boltzmann’s Constant
d. The bandwidth over which it is
measured
39. In a communication system, noise is likely
to affect the signal

a. At the transmitter
b. In the channel
c. In the information source
d. At the destination
40. The noise power generated by a resistor is
proportional to
a. Temperature
b. Bandwidth
c. a and b
d. NOTA
41. Thermal noise is also known as
a. Gaussian Noise
b. White Noise
c. Johnson noise
d. All of the above
42. This type of noise has a power spectrum
which decreases with increasing frequency.
It is most important at low frequencies from
0 to about 100 Hz).
a. Shot noise
b. Flicker noise
c. Diode noise
d. BJT noise
43. Industrial noise extends up to what
frequency?
a. 500 MHz
b. 500 GHz
c. 500 THz
d. 500 KHz
44. Impulse Noise is
a. A function of current
b. A shot duration pulse
c. Dependent of frequency
d. Dependent of temperature
45. When the power ratio of the output to input
of a circuit is 200. What is the gain in dB?
a. 23
b. 46
c. -23
d. -46
46. What is the reference level for random noise
measurement, FIA weighted?
a. -82 dBm
b. -90 dBm
c. -85 dBm
d. -77 dBm
47. A 10 dB pad has an output level of -3 dBm.
The level at the input is:
a. 13 dBm
b. -7 dBm

c. 1 dBm
d. 7 dBm
48. The sum of three signals of 45dBm each is
______ dBm.
a. 45
b. 135
c. 20
d. 50
49. It is characterized by high amplitude peaks
of short duration in the total noise spectrum
a. Intermodulation voice
b. Impulse noise
c. Dropout
d. Phase hits

50. Originally was determined by measuring the
interfering effect of noise in a Type 144
handset. A tone of 1 kHz, having a power
level of 90dBm was selected as the
reference level.
a. Noise figure
b. S/N ratio
c. Signal Figure
d. Figure of Merit
51. A power level of 50 uW could be expressed
as:
a. 1.39 dBm
b. -4.3 dBm
c. 1 dBm
d. -13 dBm
52. If a power of 0.25mW is launched into a
fiber system with an overall loss of 15 dB
the output power would be:
a. 250 u/W
b. 31.6 uW
c. 7.9 uW
d. 15 dBm
53. A system having an input power of 2 mW an
output power of 0.8mW has a loss of:
a. 2.98 dBm
b. 3.98 dB
c. 3.98 uW
d. 1.98 mW
54. An output of -10 dB means that the power
has been
a. Halved in value
b. Increased by a factor of 10
c. Reduced by a factor of 10
d. Doubled
55. Any unwanted form of energy interfering

the reception of wanted signal is called
a. Noise
b. Sideband
c. Harmonics
d. Modulation
56. Is the reduction of signal amplitude as it
passed over the transmission medium.
a. Noise
b. Distortion
c. Attenuation
d. Interference
57. Signal waveform perturbation or deviation
caused by imperfect response of the system
to the desired signal
a. Noise
b. Aliasing
c. Distortion
d. Interference
58. Signal attenuation can be corrected by
a. Filtering
b. Modulation
c. Equalization
d. Amplification
59. Distortion in a waveform can be corrected
by
a. Filtering
b. Modulation
c. Equalization
d. Amplification
60. Signal contamination by extraneous or
external sources, such as, other transmitters,
power lines, and machinery.
a. Noise
b. Distortion
c. Harmonics
d. Interference
61. Man-made or industrial noise is also known
as
a. Noise
b. Distortion
c. Interference
d. Thermal Noise
62. The noise performance of a receiver or
circuit. It is expressed as ratio of the S/N
power at the output.
a. Noise figure
b. S/N ratio
c. Signal figure
d. Figure of merit
63. Noise that is caused by natural disturbances

such as lightning discharge.
a. Static noise
b. Space noice
c. Atmospheric noise
d. A or C
64. Atmospheric or static noise becomes less
severe at frequencies
a. Below 30 KHz
b. Between 30 KHz and 300 KHz
c. Between 300 KHz and 30 MHz
d. Above 30 MHz
65. Considered as space noise or extraterrestrial
noise
a. Solar noise
b. Cosmic noise
c. Black-body noise
d. All of the above
66. Which statement is true
a. Industrial noise is usually of impulse
type
b. Distant stars produce atmospheric
noise
c. Active switches are sources of manmade noise
d. Static noise is due to lightning
discharges and other natural electric
disturbances occurring in the
atmosphere.
67. Noise performance of microwave system is
usually expressed in terms of
a. Noise voltage, Vn= √ 4 KTBR
b. Noise power, Pn = KTB
c. Noise temperature, Te = (F – 1)290
d. Noise figure, F = (S/N)I / (S/N)o
68. Which circuit contributes most to the noise
at the receiver?
a. RF amplifier
b. Mixer
c. Detector
d. Local Oscillator
69. Which noise figure represents the lowest
noise?
a. 1.5 dB
b. 2.0 dB
c. 3.7 dB
d. 4.1 dB
70. Denote the interference of noise in dB above
an adjusted reference noise. The adjusted
reference noise level was a 1 kHz tone, set at

-85 dBm
a. dBa
b. dBm
c. dBa0
d. pWp

71. The extent of noise referred to a test tone
level of zero dBm.
a. dBa
b. dBm
c. dBa0
d. pWp
72. An amplifier operating over a 4 MHz
bandwidth has a 100 Ω input resistance
and is operating at 300°K. Determine the
noise power generated.
a. 1.656 x 10-14 Watts
b. 1656 nW
c. 1.656 pW
d. 1.656 uW
73. Generally used when noise readings are
measured using the C-message weighting
network. The reference level was 1 kHz
tone, set at -90 dBm
a. dBa
b. dBm
c. dBaO
d. dBmC
74. The measurement of noise was made with a
C-message filter, and the reading is taken at
a test point where the level is zero dBm.
a. dBaO
b. dBmCo
c. dBa
d. dBmC
75. Which of the following is not an important
cause of distortion in DC signaling
a. line resistance
b. line inductance
c. line capacitance
d. all of the above
76. There are a number of different sources of
radio noise, the most important being
a. Galactic noise
b. Man-made noise
c. Atmospheric noise
d. All f the above
77. The amount of noise power is measured
using a psophometric weighting network.

This unit of measurement is generally used
in Europe where the standard reference tone
is 800 hertz, 1 picowatt.
a. dBa
b. dBm
c. dBaO
d. pWp

78. Noise produced mostly by lightning
discharges in thunderstorms.
a. White noise
b. Industrial noise
c. Atmospheric noise
d. Extraterrestrial noise
79. Propagation of man made noise is chiefly by
a. Transmission over power lines and
by ground wave
b. Space wave
c. Sky wave
d. None of these
80. A more precise evaluation of the quality of a
receiver as far as noise is concerned
a. S/N
b. VSWR
c. Noise factor
d. Noise margin
81. NIF stands for
a. Non-intrinsic figure
b. Noise interference figure
c. Noise improvement factor
d. Narrow intermediate frequency
82. External noise fields are measured in terms
of
a. Dc values
b. Rms values
c. Peak values
d. Average values
83. Form of interference caused by rain, hail,
snow or dust storms
a. Shot noise
b. Galactic noise
c. Impulse noise
d. Precipitation static
84. Extra-terrestrial noise is observable at
frequencies from
a. 0 to 20KHz
b. 8 MHz to 1.43 GHz
c. 5 to 8 GHz
d. 15 to 160 MHz

85. Industrial noise is observable from
a. 15 to 160 MHz
b. 200 to 3000 MHz
c. 0 to 10 kHz
d. 8 Mhz to 1.43 GHz
86. Noise that becomes significant at VHF range
and above
a. Atmospheric
b. Transit-time
c. Galactic
d. White
87. Noise figure for an amplifier with noise is
always
a. 0 dB
b. Infinite
c. Less than 1
d. Greater than 1
88. The noise generated by the tube, transistor
or integrated circuit in an amplifier.
a. White noise
b. Amplification noise
c. Active noise
d. Dynamic Noise
89. Electrical noise inherent to a particular
device, circuit or system that remains when
no other signal is present.
a. Shot noise
b. Thermal noise
c. Background noise
d. Static noise
90. A wideband form of impulse noise generated
by the electric arc in the spark plugs of an
internal combustion engine. This noise is a
common problem in mobile radio system.
a. Thermal noise
b. Shot noise
c. Amplification noise
d. Ignition noise
91. The amount of power in dB referred to one
Kilowatt
a. dBW
b. dBk
c. dBm
d. Dbv
92. Noise in any form of electromagnetic
interference that can be traced to non-natural
causes.
a. Man-made noise

b. Distortion
c. External noise
d. Internal noise
93. The frequency range wherein noise is said to
be intense.
a. Noise equivalent bandwidth
b. Spectral response
c. Cut-off frequency
d. Noise cut-off frequency
94. Refers to the temperature that corresponds to
the spectral energy distribution of a noise.\
a. Absolute temperature
b. Temperature band
c. Noise-equivalent temperature
d. Critical temperature
95. A passive circuit, usually consisting of
capacitance and/or inductance, that I
inserted in series with the a-c power cord of
an electronic device which will allow the
60-Hz current to pass and suppressed high
frequency noise components.
a. Noise filter
b. Noise limiter
c. Noise floor
d. Noise quieting
96. What do you call the level of background
noise, relative to some reference signal.
a. Noise figure
b. Minimum noise
c. Reference noise
d. Noise floor
97. A circuit often used in radio receivers that
prevents externally generated noise from
exceeding amplitude. They are also called
noise clippers
a. Noise floor
b. Noise filter
c. Noise limiter
d. Noise clamper
98. It is referred to as a short burst of
electromagnetic energy.
a. Pulse
b. Noise pulse
c. Spike
d. Noise floor
99. The reduction of internal noise level in a
frequency-modulated (FM) receiver as a
result of an incoming signal.
a. Noise quieting
b. Noise limiting
c. Noise suppression
d. Noise degredation

100. Noise generated within electronic
equipment by either passive or active
components.
a. Shot noise
b. Thermal noise
c. Circuit noise
d. External noise

Modulation
Multiple choice. Encircle the letter which
corresponds to your answer.
1. Having an information signal change some
characteristic of a carrier signal is called
a. Multiplexing
b. Modulation
c. Duplexing
d. Linear mixing
2. Which of the following is not true about
AM?
a. The carrier amplitude varies.
b. The carrier frequency remains
constant.
c. The carrier frequency changes.
d. The information signal amplitude
changes the carrier amplitude.
3. The opposite of modulation is
a. Reverse modulation
b. Downward modulation
c. Unmodulation
d. Demodulation
4. The circuit used to produce modulation is
called
a. Modulator
b. Demodulator

c. Variable gain amplifier
d. Multiplexer
5. A modulator circuit performs what
mathematical operation on its two inputs?
a. Addition
b. Multiplication
c. Division
d. Square root
6. The ratio of the peak modulating signal
voltage to the peak carrier voltage is referred
to as
a. The voltage ratio
b. Decibels
c. The modulation index
d. The mix factor
7. If m is greater than 1, what happens?
a. Normal operation
b. Carrier drops to zero
c. Carrier frequency shifts
d. Information signal is distorted
8. For ideal AM, which of the following is
true?
a. m = 0
b. m = 1
c. m < 1
d. m > 1
9. The outline of the peaks of a carrier has the
shape of the modulating signal and is called
the
a. Trace
b. Waveshape
c. Envelope
d. Carrier variation
10. Overmodulation occurs when
a. Vm > Vc
b. Vm < Vc
c. Vm = Vc
d. Vm = Vc = 0
11. The values of Vmax and Vmin as read from an
AM wave on oscilloscope are 2.8 and 0.3.
the percentage of modulation is
a. 10.7 %
b. 41.4 %
c. 80.6 %
d. 93.3 %
12. The new signals produced by modulation are
called
a. Spurious emissions
b. Harmonics
c. Intermodulation products

d. Sidebands
13. A carrier of 880 kHz is modulated by a 3.5
kHz sine wave. The LSB and USB are,
respectively,
a. 873 and 887 kHz
b. 876.5 and 883.5 kHz
c. 883.5 and 876.5 kH
d. 887 and 873 kHz
14. A display of signal amplitude versus
frequency is called the
a. Time domain
b. Frequency Spectrum
c. Amplitude Spectrum
d. Frequency Domain
15. Most of the power in an AM signal is in the
a. Carrier
b. Upper sideband
c. Lower sideband
d. Modulating signal
16. An AM signal has a carrier power of 5 W.
the percentage of modulation is 80% the
total sideband power is
a. 0.8 W
b. 1.6 W
c. 2.5 W
d. 4.0 W
17. For 100 % modulation, what percentage of
power is in each sideband?
a. 25 %
b. 33.3 %
c. 50 %
d. 100 %
18. An AM transmitter has a percentage of
modulation of 88. The carrier power is 440
W. The power is 440W. The power in one
sideband is
a. 85 W
b. 110 W
c. 170 W
d. 610 W
19. An AM transmitter antenna current is
measured with no modulation and found to
be 2.6 amperes. With modulation, the
current rises to 2.9 amperes. The percentage
of modulation is
a. 35 %
b. 70 %
c. 42 %
d. 89 %
20. What is the carrier power in the problem

above if the antenna resistance is 75 ohms?
a. 195 W
b. 631 W
c. 507 W
d. 792 W
21. In an AM signal, the transmitted information
is contained within the
a. Carrier
b. Modulating signal
c. Sidebands
d. Envelope
22. An AM signal without the carrier is called
a(n)
a. SSB
b. Vestigial sideband
c. FM signal
d. DSB
23. What is the minimum AM signal needed to
transmit information?
a. Carrier plus sidebands
b. Carrier only
c. One sideband
d. Both sideband
24. The main advantage of SSB over standard
AM or DSB is
a. Less spectrum space is used
b. Simpler equipment is used
c. Less power is consumed
d. A higher modulation percentage
25. In SSB, which sideband is the best to use?
a. Upper
b. Lower
c. Neither
d. Depends upon the use
26. The typical audio modulating frequency
range used in radio and telephone
communication is
a. 50 Hz to 5 kHz
b. 50 Hz to 15 kHz
c. 100Hz to 10kHz
d. 300 Hz to 3 kHz
27. An AM signal with a maximum modulating
signal frequency of 4.5 kHz has a total
bandwidth of
a. 4.5 kHz
b. 6.75 kHz
c. 9 kHz
d. 18 kHz
28. The modulation system used for telegraphy
is

a.
b.
c.
d.

Frequency-shift keying
Two-tone modulation
Pulse-code modulation
Single-tone modulation

29. The process of translating a signal, with or
without modulation, to a higher or lower
frequency for processing is called
a. Frequency multiplication
b. Frequency division
c. Frequency shift
d. Frequency conversion
30. Frequency translation is carried out by a
circuit called a
a. Translator
b. Convertor
c. Balanced modulator
d. Local oscillator
31. An input signal of 1.8 MHz is mixed with a
local oscillator of 5 MHz. A filter selects the
difference signal. The output is
a. 1.8 MHz
b. 3.2 MHz
c. 5 MHz
d. 6.8 MHz
32. One type of pulse communications system
uses pulse that appear as a group, and which
vary in number according to the loudness of
the voice. This type of pulse modulation is
called
a. Pulse duration modulation
b. Pulse amplitude modulation
c. Pulse code modulation
d. Pulse position modulation
33. An SSB transmitter produces a 400-V peak
to peak signal across a 52-Ω antenna load.
The PEP output is
a. 192.2 W
b. 384.5 W
c. 769.2 W
d. 3077 W
34. The output power of an SSB transmitter is
usually expressed in terms of
a. Average power
b. RMS power
c. Peak-to-peak power
d. Peak envelope power
35. The letter-number designation B8E is a form
of modulation also known as
a. Pilot-carrier system

b. Independent sideband emission
c. Lincomlex
d. Vestigal sideband transmission
36. Amplitude modulation is the same as
a. Linear mixing
b. Analog multiplication
c. Signal summation
d. Inductor
37. In a diode modulator, the negative half of
the AM wave is supplied by a(n)
a. Tuned circuit
b. Transformer
c. Capacitor
d. Inductor
38. Amplitude modulation can be produced by
a. Having the carrier vary a
resistance
b. Having the modulating signal vary a
capacitance
c. Varying the carrier frequency
d. Varying the gain of an amplifier
39. Amplitude modulators that vary the carrier
amplitude with the modulating signal by
passing it through an attenuator work on the
principle of
a. Rectification
b. Resonance
c. Variable resistance
d. Absorption
40. The component used to produce AM at very
high frequencies is a
a. Varactor
b. Thermistor
c. Cavity resonator
d. PIN diode
41. Amplitude modulation generated at a very
low voltage or power amplitude is known as
a. High-level modulation
b. Low-level modulation
c. Collector modulation
d. Minimum modulation
42. A collector modulator has a supply voltage
of 48 V. The peak-to-peak amplitude of the
modulating signal for 100 percent
modulation is
a. 24 V
b. 48 V
c. 96 V
d. 120 V

43. A collector modulated transmitter has a
supply voltage of 24 V and collector current
of 0.5 A. The modulator power for 100
percent modulation is
a. 6 W
b. 12 W
c. 18 W
d. 24 W
44. The circuit that recovers the original
modulating information from an AM signal
is known as a
a. Modulator
b. Demodulator
c. Mixer
d. Crystal set
45. The most commonly used amplitude
demodulator is the
a. Diode mixer
b. Balanced modulator
c. Envelope detector
d. Crystal filter
46. A circuit that generates the upper and lower
sidebands but no carrier is called a(n)
a. Amplitude modulator
b. Diode detector
c. Class C amplifier
d. Balanced modulator
47. The inputs to a balance modulator are 1
MHz and a carrier of 1.5 MHz. The outputs
are
a. 500 kHz
b. 2.5 MHz
c. 1.5 MHz
d. Both a and b
48. A widely used balanced modulator is called
the
a. Diode bridge circuit
b. Full-wave bridge rectifier
c. Lattice Modulator
d. Balanced bridge modulator
49. In a diode ring modulator, the diodes act like
a. Variable resistors
b. Switches
c. Rectifiers
d. Variable capacitors

50. The output of a balanced modulator is
a. AM
b. FM
c. SSB

d. DSB
51. The principal circuit in the popular
1496/1596 IC balanced modulator is a
a. Differential amplifier
b. Rectifier
c. Bridge
d. Constant current source
52. The most commonly used filter in SSB
generators uses
a. LC network
b. Mechanical resonators
c. Crystals
d. RC networks and op amps
53. The equivalent circuit of a quartz crystal is a
a. Series resonant circuit
b. Parallel resonant circuit
c. Neither a nor b
d. Both a and b
54. A crystal lattice filter has crystal frequencies
of 27.5 and 27.502 MHz. The bandwidth is
approximately
a. 2 kHz
b. 3kHz
c. 27.501 MHz
d. 55.502 MHz
55. An SSB generator has a sideband filter
centered at 3.0 MHz. The modulating signal
is 3kHz. To produce both upper and lower
sidebands, the following carrier frequencies
must be produced:
a. 2.7 and 3.3 MHz
b. 3.3 and 3.6 MHz
c. 2997 and 3003 kHz
d. 3000 and 3003 kHz
56. In the phasing method of SSB generation,
one sideband is canceled due to
a. Phase shift
b. Sharp selectivity
c. Carrier suppression
d. Phase inversion
57. A balanced modulator used to demodulate a
SSB signal is called a(n)
a. Transporter
b. Product detector
c. Converter
d. Modulator
58. Frequency translation is done with a circuit
called a
a. Summer
b. Multiplier

c. Filter
d. Mixer
59. The inputs to a mixer are fo and fm. In down
conversion, which of the following mixer
output signals is selected?
a. Fo
b. Fm
c. Fo – fm
d. Fo + fm
60. Mixing for frequency conversion is the same
as
a. Rectification
b. AM
c. Linear summing
d. Filtering
61. Which of the following can be used as a
mixer?
a. Balanced modulator
b. FET
c. Diode modulator
d. All the above
62. The desired output from a mixer is usually
selected with a
a. Phase-shift circuit
b. Crystal filter
c. Resonant circuit
d. Transformer
63. The amount of frequency deviation from the
carrier center frequency in an FM
transmitter is proportional to what
characteristic of the modulating signal?
a. Amplitude
b. Phase
c. Angle
d. Duty Cycle

64. Both FM and PM are types of what kind of
modulation?
a. Amplitude
b. Phase
c. Angle
d. Duty Cycle
65. If the amplitude of the modulating signal
decreases, the carrier deviation
a. Increases
b. Decreases
c. Remains constant
d. Both b and c
66. In PM, a frequency shift occurs while what
characteristic of the modulating signal is

changing?
a. Shape
b. Phase
c. Frequency
d. Amplitude
67. Maximum frequency deviation of a PM
signal occurs at
a. Zero crossing points
b. Peak positive amplitude
c. Peak negative amplitude
d. Peak positive or negative amplitudes
68. A 100-MHz carrier is deviated 50 KHz by a
4 kHz signal. The modulation index is
a. 5
b. 8
c. 12.5
d. 40
69. The maximum deviation of an FM carrier is
2 kHz by a maximum modulating signal of
400 Hz. The deviation ratio is
a. 0.2
b. 5
c. 8
d. 40
70. According the Nyquist theorem, the
sampling rate that can be used in a PCM
system is _____ the highest audio frequency
a. Once
b. Eight times
c. Twice
d. Thrice
71. SSB transmission requires only _______ of
the bandwidth for a DSBFC
a. ¼
b. 2/3
c. ½
d. ¾
72. Which of the following pulse modulation
systems is analog?
a. Delta
b. Differential PCM
c. PWM
d. PCM
73. Which of the following is not a major
benefit of FM over AM?
a. Greater efficiency
b. Noise immunity
c. Capture Effect
d. Lower Complexity and Cost
74. The primary disadvantage of FM is it

a. Higher cost and complexity
b. Excessive use of spectrum space
c. Noise susceptibility
d. Lower efficiency
75. The phenomenon of a strong FM signal
dominating weaker signal on a common
frequency is referred to as the
a. Capture effect
b. Blot out
c. Quieting factor
d. Dominating syndrome
76. If the plate supply voltage for a platemodulated class C amplifier is E, the
maximum plate-cathode voltage could be
almost as high as
a. 4E
b. 3E
c. 2E
d. E
77. In a low-level AM system, amplifiers
following the modulated stage must be
a. Linear devices
b. Harmonic devices
c. Class C amplifiers
d. Nonlinear devices
78. If the carrier of a 100 percent modulated AM
wave is suppressed, the percentage power
saving will be
a. 50
b. 150
c. 100
d. 66.66
79. Leak-type bias is used in a plate-modulated
class C amplifier to
a. Prevent tuned circuit damping
b. Prevent excessive grid current
c. Prevent overmodulation
d. Increase the bandwidth
80. The output stage of a television transmitter
is most likely to be a
a. Plate-modulated class C amplifier
b. Grid-modulated class C amplifier
c. Screen-modulated class C amplifier
d. Grid-modulated class A amplifier
81. The modulation index of an AM wave is
changed from 0 to 1. The transmitted power
is
a. Unchanged
b. Halved
c. Doubled

d. Increased by 50 percent
82. One of the advantages of base modulation
over collector modulation of a transistor
class C amplifier is
a. The lower modulating power
required
b. Higher power output per transistor
c. Better efficiency
d. Better linearity
83. A carrier simultaneously modulated by two
sine waves with modulation indices of 0.3
and 0.4; the total modulation index
a. 1
b. Cannot be calculated unless the
phase relations are known
c. 0.5
d. 0.7
84. In the stabilized reactance modulator AFC
system,
a. The discriminator must have a fast
time constant to prevent
demodulation
b. The higher the discriminator
frequency, the better the oscillator
frequency stability
c. The discriminator frequency must
not be too low, or the system will
fail
d. Phase modulation is converted into
FM by the equalizer circuit
85. In the spectrum of a frequency of a
frequency-modulated wave
a. The carrier frequency disappears
when the modulation index is large
b. The amplitude of any sideband
depends on the modulation index
c. The total number of sidebands
depends on the modulation index
d. The carrier frequency cannot
disappear
86. The difference between phase and frequency
modulation
a. Is purely theoretical because they are
the same in practice
b. Is too great to make the two systems
compatible
c. Lies in the poorer audio response of
phase modulation
d. Lies in the different definitions of
the modulation index

87. Indicate the false statement regarding the
Armstrong modulation system.
a. The system is basically phase, not
frequency, modulation
b. AFC is not needed, as a crystal
oscillator is used
c. Frequency multiplication must be
used
d. Equalization is unnecessary
88. An FM signal with a modulation index mf is
passed through a frequency tripler. The
wave in the output of the tripler will have a
modulation index of
a. mf/3
b. mf
c. 3 mf
d. 9mf
89. An FM signal with a deviation δ is passed
through a mixer, and has its frequency
reduced fivefold. The deviation in the output
of the mixer is
a. 5 δ
b. Indeterminate
c. δ/5
d. δ
90. A pre-emphasis circuit provides extra noise
immunity by
a. Boosting the bass frequencies
b. Amplifying the higher audio
frequencies
c. Pre-amplifying the whole audio band
d. Converting the phase modulation to
FM
91. Since noise phase modulates the FM wave,
as the noise sideband frequency approaches
the carrier frequency, the noise amplitude
a. Remains constant
b. Decreased
c. Increased
d. Equalized
92. When the modulating frequency is doubled,
the modulation index is halved, and the
modulating voltage remains constant. The
modulating system is
a. Amplitude modulation
b. Phase modulation
c. Frequency modulation
d. Any of the three
93. Indicate which one of the following is not an
advantage of FM over AM

a. Better noise immunity is provided
b. Lower bandwidth is required
c. The transmitted power is more useful
d. Less modulating power is required
94. One of the following is an indirect way of
generating FM. This is the
a. Reactance FET modulator
b. Varactor diode modulator
c. Armstrong modulator
d. Reactance bipolar transistor
modulator
95. Indicate the false statement regarding the
advantages of SSB over double-sideband,
full-carrier AM.
a. More channel space is available
b. Transmitter circuits must be more
stable, giving better reception
c. The signal is more noise resistance
d. Much less power is required for the
same signal strength
96. When the modulation index of an AM wave
is doubled, the antenna current is also
doubled. The AM system being used is
a. A3H
b. A5C
c. A3J
d. A3
97. Indicate which of the following advantages
of the phase cancellation method of
obtaining SSB over the filter method is false
a. Switching from one sideband to the
other is simpler
b. It is possible to generate SSB at any
requency
c. SSB with lower audio frequencies
present can be generated
d. There are more balanced
modulators; therefore the carrier
is suppressed better
98. The most commonly used filter in SSB
generation are
a. Mechanical
b. RC
c. LC
d. Low- pass
99. Indicate in which one of the following only
one sideband is transmitter
a. A3H
b. A3
c. A3B
d. A5C
100. A3A modulation is sometimes used to

a. Allow the receiver to have a
frequency synthesizer
b. Simplify the frequency stability
problem in reception
c. Reduce the power that must be
transmitted
d. Reduce the bandwidth required for
transmission.

Transmission Lines
Multiple choice. Encircle the letter which
corresponds to your answer.
1. In practice, the transmission lines are almost
connected to antennas that have a _____.
a. Resistive load whose resistance is
greater than the characteristic
impedance of the line
b. Resistive load whose resistance is
less than the characteristic
impedance of the line
c. Resistive load at the resonant
frequency
d. Capacitive load
2. When the transmission line is matched to the
load, it
a. Transfers maximum current to the
load
b. Transfers maximum voltage to the
load
c. Transfers maximum power to the
load
d. Reduces the load current
3. Conventional transmission media include
a. Twisted cable pair

b. Waveguide
c. Fiber optic cable
d. All of these
4. To couple a coaxial line to a parallel wire
line, it is best to use a _____
a. Slotted line
b. Directional coupler
c. Balun
d. All of these
5. Impedance inversion may be obtained with
a. An open circuited stub
b. A short circuited stub
c. A quarterwave line
d. A half-wave line
6. To be properly matched, the ratio of
maximum to minimum voltage along a
transmission line should be equal to
a. 50
b. 10
c. 2
d. 1

7. When ZL ≠ Zo, the powersent down the line
toward the load is called the
a. The incident power
b. The reflected power
c. The power dissipation
d. The carrier power
8. For transmission line load matching over a
range of frequencies, it is best to use a
a. Balun
b. Broadband directional coupler
c. Double stub
d. Single adjustable stub
9. A short section of a transmission line, open
or shorted that is used to match the
impedance of the line to that of an antenna
or transmitter.
a. Slotted line
b. Stub
c. Wavetrap
d. Lecher wire
10. The property of a material that determines
how much electrostatic energy can be stored
per unit volume when voltage is applied
a. Permeability
b. Magnetic effect
c. Capacitance
d. Permittivity
11. The value of the total opposition of the

transmission media to the flow of
electromagnetic field energy is called
a. Characteristic impedance
b. Velocity factor
c. Standing waves
d. Reflected waves
12. When mismatch is great, this power actually
cause damage to the transmitter or the line
itself.
a. The incident power
b. The reflected power
c. The power dissipation
d. The carrier power
13. What is the velocity factor for non-foam
dielectric 50 or 75 ohm flexile coaxial cable
such as RG 8, 11, 58 and 59?
a. 270
b. 0.10
c. 0.66
d. 0.30
14. The measure of the superiority of a material
over a vacuum as a path for magnetic lines
of force is
a. Permittivity
b. Permeability
c. Conductivity
d. Resistivity
15. The number of standing waves on the wire is
equal to the length of the wire divided by a
half wavelength. The principle which allows
antennas to operate at different frequencies
which are integral multiples of the
fundamental frequency is called_______.
a. Harmonic operation
b. Decimonic operation
c. Electromagnetic reverberation
d. Asynchronous operation
16. A coax line has an attenuation of 2.4 dB per
100 ft. the attenuation for 2.75 ft. is _____
dB.
a. 2.4
b. 4.8
c. 3.3
d. 6.6
17. When a quarter wave stub is used to match a
600 ohm antenna to aline of 52 ohms, the
impedance of the matching stub must be
____ ohms.
a. 176
b. 200
c. 150
d. 300

18. The characteristic impedance of a
transmission line is determined by
a. Its length
b. Its height above ground
c. Its physical construction
d. The operating frequency
19. When the diameter of two conductors of a
two-wire transmission line is held constant,
the effect of decreasing the distance between
the conductors is to
a. Decrease the impedance
b. Increase the surge impedance
c. Increase the radiation resistance
d. Decrease SWR

20. Considering a coaxial transmission line,
maximum voltage on the line divided by the
minimum voltage equals the
a. Characteristic impedance
b. ISWR
c. VSWR
d. Inductive reactance
21. In a transmission line, if the SWR or
maximum current to a minimum current
ratio of 2:1, the ratio of the maximum
voltage to the minimum voltage is
a. 1:4
b. 4:1
c. 1:2
d. 2:1
22. Transmission lines are either balanced or
unbalanced with respect to
a. Negative terminal
b. Input
c. Ground
d. Positive terminal
23. The load is properly matched with the
transmission line if the standing wave ratio
is equal to
a. 50
b. 10
c. 5
d. 1
24. The radiation resistance of a quarterwave
antenna is
a. 49 ohms
b. 288 ohms
c. 72 ohms
d. 144 ohms
25. A radio transmission line of 500 ohms

impedance is to be connected to an antenna
having an imepedance of 200 ohms. What is
the impedance of a quarter wave matching
line?
a. 300
b. 316
c. 316.5
d. 361
26. The VSWR for a line terminated in its Zo is
a. 0
b. 1
c. 1.5
d. Infinity
27. Which of the following is used to measure
SWR?
a. Multimeter
b. Reflectometer
c. Spectrum analyzer
d. Oscilloscope
28. A 75 – j50 ohm load is connected to a
coaxial transmission line of Zo = 75 ohms at
10 GHz. The best method of matching
consists in connecting
a. A short circuited stub at the load
b. A capacitance at some specific
distance from the load
c. An inductance at the load
d. A short-circuited stub at some
specific distance from the load
29. For a two-wire line, Zo is higher when
a. The wire size is small with respect
to the spacing of the conductors
b. The spacing is varied in accordance
with the frequency
c. The D:d ratio is smaller
d. The wire is large with respect to the
spacing of the conductors
30. A resultant wave due to the combination of
incident and reflected wave
a. Electromagnetic wave
b. Sine wave
c. Standing wave
d. Current
31. For transmission line load matching over a
range of frequencies, it is best to use a
a. Balun
b. Broadband directional coupler
c. Double stub
d. Single stub
32. If the load impedance matches the

characteristic impedance of the line, there
are _____ standing waves.
a. More
b. Less
c. No
d. Ten(10)
33. VSWR stands for
a. Voltage sending wave ratio
b. Voltage receiving wave ratio
c. Very small wave radiation
d. Voltage standing wave ratio

34. Reflections on a transmission line can occur
when
a. Impedance of the source and load are
matched
b. Impedance of the source and the
load are mismatched
c. Resonance conditions are obtained
d. Power transfer between source and
load is maximum
35. A transmission line with characteristic
impedance (Zo) of 300 ohms is terminated
in a resistance load (RI). If by measurement,
the minimum and maximum voltage through
the load are 12 and 20 micro volts,
respectively, what is the SWR?
a. 1.67
b. 0.6
c. 6.7
d. 3.67
36. A measure of the mismatched between line
and load impedance is called as
a. Reflection coefficient
b. Standing wave ratio
c. Loss
d. Standing waves
37. Transmission lines when connected to
antenna have
a. Capacitive load
b. Resistive load whose resistance is
less than characteristic impedance
c. Resistive load at the resonant
frequency
d. Resistive load whose resistance is
greater than the characteristic
impedance of the line
38. At matched condition, SWR is equal to
a. Zero
b. One

c. 100
d. Infinite
39. An HF transmission line has a characteristic
impedance of 600 ohms and is terminated by
an antenna. The SWR along the line when
the antenna impedance is 500 ohms is
a. 1.2:1
b. 1:2.1
c. 2:1
d. 1:2
40. A characteristic of an infinite transmission
line is that
a. The impedance in equals
impedance out
b. It carries waves at the velocity of
light
c. It can be connected to mismatched
loads
d. The impedance varies with the
length of the line
41. A quarter wave transmission line shorted at
the end:
a. Has the characteristics of parallel
tuned circuit
b. Has the characteristics of a series
tuned circuit
c. Has a minimum current at the end
d. Reflects a low impedance to the
supply
42. The outer conductor of a coaxial
transmission line is usually grounded at the:
a. Input and output
b. Output only
c. Input only
d. Point of infinite resistance
43. A certain feedline has a high SWR. It can be
caused by:
a. An impedance mismatched
b. Use of non-resonant line
c. Matching the load to the line
d. Excessive transmitter output
44. If the input impedance of an antenna is 300
ohms and it is fed with a 600 ohm balanced
transmission line, the SWR on the line is
a. 4
b. 3
c. 2
d. 0.5
45. A radio transmission line of 300 ohms
impedance to be connected to an antenna

having an input impedance of 150 ohms.
The impedance if a quarter wave matching
line is ___ ohms
a. 212
b. 450
c. 600
d. 150
46. The ratio of the reflected voltage to the
incident voltage on the transmission line is
termed as
a. Reflection coefficient
b. Standing wave ratio
c. Loss
d. Standing waves
47. Indicate the three types of transmission line
energy losses
a. Radiation, I(squared) R and
dielectric Heating
b. Conductor heating, dielectric heating
and radiation resistance
c. I(squared)R, RL and temperature
d. Dielectric separation insulation
breakdown and radiation
48. Termination means
a. Load connected to the output end
of a transmission line
b. Result of disconnecting a line from a
transmitter
c. Looking back impedance of a line
with no load
d. Result of cutting both ends of a
conductor
49. When transmission line uses ground return,
it is called a/n _____ line.
a. Ungrounded
b. Unbalanced
c. Grounded
d. Balanced
50. Permeability is the measure of superiority of
a material over a vacuum as a path of
magnetic lines of force. The permeability of
free space is equal to _____ henry/meter
a. 1.257 x 10-6
b. 1.527 x 10-6
c. 7.251 x 10-6
d. 5.217x10-6
51. The most commonly used transmission line
is a
a. Two-wire balanced line
b. Single line

c. Three-wire line
d. Coax
52. The characteristic impedance of a
transmission line does not depend upon its
a. Length
b. Conductor diameter
c. Conductor spacing
d. Thickness of armor
53. What is the impedance of a balance 4-wire
with a diameter of 0.25cm and spaced 2.5
cm apart using an insulator with a dielectric
constant of 2.56?
a. 100 ohms
b. 65 ohms
c. 75 ohms
d. 50 ohms
54. It is required to match a 73-ohm antenna to a
600 ohm polyethylene coaxial feeder line,
with a velocity factor of 0.66 by means of a
quarter wave matching a transformer. At a
frequency of 150MHz, the impedance of the
matching section is____ ohms.
a. 209.28
b. 310.5
c. 150.28
d. 450.82
55. If the terminating impedance is exactly
equal to the characteristic impedance of the
transmission line, the return loss is____
a. Zero
b. Infinity
c. One
d. Negative
56. The characteristic impedance of a
transmission line is the impedance measured
at the ____ when its length is infinite.
a. Shorted end of the line
b. Midsection
c. Input
d. Output
57. The characteristic impedance of a
transmission line is 70 ohms and has a load
of 35 ohms. The SWR and reflection
coefficient are _____ and _____
respectively
a. 2 and 0.333
b. 1 and 0.666
c. 2 and 0.666
d. 1 and 0.333
58. It is required to match a 200 ohm load to a
300 ohm transmission line to reduce the
SWR and attain resonace. A quarter wave

transformer used, directly connected to the
load has a Zo of ____ ohms.
a. 245
b. 425
c. 524
d. 254
59. What quarter wave transformer will match a
100 ohm-lne to an antenna whose value is
175 ohms?
a. 150 ohms
b. 137.5 ohms
c. 132.29 ohms
d. 16.58 ohms
60. The mismatch between antenna and
transmission line impedance cannot be
corrected by
a. Using an LC network
b. Adjusting antenna length
c. Using a balun
d. Adjusting the length of the
transmission line

61. A pattern of voltage and current variation
along a transmission line not terminated in
ints characteristic impedance is called
a. An electric field
b. Radio waves
c. Standing waves
d. Magnetic field
62. The most desirable value of SWR on a
transmission line is
a. 0
b. 1
c. 2
d. Infinity
63. In transmission lines, the most desisrable
reflection coefficient is
a. Zero
b. 0.5
c. 1
d. Infinity
64. At very high frequencies, transmission lines
are used as _____.
a. Tuned circuits
b. Antennas
c. Insulators
d. Resistors
65. What is the reflection coefficient of a 100
ohm characteristic impedance line and a 300
ohm load?

a. 0.25
b. 0.3
c. 0.5
d. 0.75
66. The minimum voltage along a transmission
line is 260 volts, while the maximum is 390
volts. The SWR is
a. 0.67
b. 1.0
c. 1.2
d. 1.5
67. A single conductor running from the
transmitter to the antenna
a. RG-8/U
b. Single line wire
c. Twin-lead
d. Microstrip
68. What characteristic impedance is needed to
match a 50-ohm line to a 300 ohm-load?
a. 221 ohms
b. 122 ohms
c. 212 ohms
d. 112 ohms
69. Indicate the false statement. The SWR on a
transmission line is infinity; the line is
terminated in
a. Short circuit
b. A complex impedance
c. An open circuit
d. A pure reactance
70. A (75 – j50) Ω load is connected to a coaxial
transmission line of Zo = 75 Ω at 10 GHz.
The best method of matching consists in
connecting
a. A short circuited stub
b. An inductance at the load
c. A capacitance at some specific
distance from the load
d. A short circuited stub at some
specific distance from the load
71. The velocity factor of a transmission line
a. Depends on the dielectric constant
of the material used
b. Increases the velocity along the
transmission line
c. Is governed by the skin effect
d. Is higher for a solid dielectric than
for air
72. What is the characteristic impedance of a
single wire with diameter d=0.25mm placed

at the center between grounded parallel
planes separated by 1mm apart. The wire is
held by a material with a velocity factor of
0.75
a. 85 ohms
b. 63 ohms
c. 50 ohms
d. 75 ohms
73. Coaxial lines are used on those system
operating ________.
a. Below 2 GHz
b. At 300 MHz
c. Above 10 KHz
d. Above 10 GHz
74. Referred to the dielectric constant of a
transmission line material
a. Inductance and capacitance
b. Velocity factor
c. Characteristic impedance
d. Propagation velocity
75. The main advantage of the two-hole
directional coupler is
a. Low directional coupling
b. Poor directivity
c. High SWR
d. Narrow bandwidth
76. To couple a coaxial line to a parallel-wire
line, it is best to use a
a. Slotted line
b. Balun
c. Directional coupler
d. Quarter-wave transformer
77. What is the meaning of the term velocity
factor of a transmission line?
a. The index of shielding for coaxial
cable
b. The velocity of the wave on the
transmission line multiplied by the
velocity of light in a vacuum
c. The ratio of the characteristic
impedance of the line to the
terminating impedance
d. The velocity of the wave on the
transmission line divided by the
velocity of light in a vacuum
78. A transmission line consisting of two
conductors that have equal resistance per
unit length.
a. Unbalance line
b. Open-wire line

c. Balanced line
d. Coaxial line
79. Which if the following is not a common
transmission line impedance?
a. 50 Ω
b. 75 Ω
c. 120 Ω
d. 300 Ω
80. For a maximum absorption of power at the
antenna, the relationship between the
characteristic impedance of the line Zo and
the load impedance Zl should be
a. Zo = ZL
b. Zo > ZL
c. Zo < ZL
d. Zo = 0
81. Which of the following determines the
characteristics of a transmission line?
a. Inductance
b. Capacitance
c. Physical dimensions
d. Length
82. In the study of transmission cable, twin lead
is also referred to as a ______ .
a. Twisted pair
b. Double cable
c. Ribbon cable
d. Open pair
83. A 50 Ω coax is connected to a 73 Ω the
SWR is
a. 0.685
b. 1
c. 1.46
d. 2.92
84. A ratio expressing the percentage of incident
voltage reflected on a transmission line is
known as the
a. Velocity factor
b. Standing-wave ratio
c. Reflection coefficient
d. Line efficient
85. Three feet is one wavelength at a frequency
of
a. 100 MHz
b. 164 MHz
c. 300 MHz
d. 328 MHz
86. An open quarter-wave line at the operating
frequency acts like a(n)
a. Series resonant circuit

b. Parallel resonant circuit
c. Capacitor
d. Inductor
87. A shorted half-wave line at the operating
frequency acts like a(n)
a. Capacitor
b. Inductor
c. Series resonant circuit
d. Parallel resonant circuit
88. At UHF and microwave frequencies,
transmission lines are commonly used as
a. Antenna
b. Coupler
c. Resonant circuit
d. Transformer

89. The transmission medium subjects the
transmitted signal to be
a. Modulated
b. Amplified
c. Attenuated
d. Boosted
90. Transmission line is a two-wire cable that
connects the transmitter to the antenna or the
antenna to the receiver. The purpose of the
transmission line is to
a. Amplify the RF signal
b. Modulate the signal
c. Carry the RF energy for the
desired distance
d. All of the above
91. These conductors are uniformly spaced by
insulators. They have low losses at low
medium frequencies and are economical to
construct and maintained
a. Coaxial cables
b. Open-wire transmission lines
c. Optical cables
d. Waveguides
92. To prevent radiation losses and interference
from external sources, the inner conductor
of this transmission line is completely
enclosed with a metal sheath or braid
a. Coaxial cable
b. Open-wire transmission lines
c. Optical cables
d. Waveguides
93. The term “balanced line” means that
a. Both conductors carry currents that

flow in opposite directions
b. Conductors present equal
capacitance to ground
c. One conductor is connected to
ground
d. Both A and B
94. The characteristic impedance of a
transmission line is determined by:
a. Its operating frequency
b. Its length
c. Its physical size and arrangement
d. The signal applied at the input
terminal
95. The disturbance parameters of the
transmission line are: the series resistance;
the series inductance; the shunt capacitance
and the shunt conductance. What parameter
was determined due to dielectric losses?
a. Series resistance
b. Series inductance
c. Shunt capacitance
d. Shunt conductance
96. Shunt capacitance was determined due to:
a. Conductors were closed to each
other
b. The length and diameter of the
conductors
c. Dielectric loses
d. Flux linkages
97. Series resistances was determined due to:
a. Conductors were closed to each
other
b. The length and diameter of the
conductors
c. Dielectric losses
d. Flux linkages
98. At radio frequencies was determined due to:
a. Characteristic
b. Inductive reactance is much larger
than the shunt conductance
c. Capacitive reactance is much larger
than the shunt conductance
d. Both b and c
99. Determine the characteristic impedance of a
transmission line which has a capacitance of
30 pF/m and an inductance of 75 nH/m
a. 5 Ω
b. 50 Ω
c. 500 Ω
d. 5 K Ω
100. If a charge in the dielectric material
decreases the capacitance, the characteristic

impedance is
a. Kept constant
b. Decreased
c. Increased
d. Halved

Wave Propagation
Multiple choice. Encircle the letter which
corresponds to your answer.
1. Whether or not polarization of an antenna is
linear depends on changes in direction in
which:
a. The direction in which the electric
plane is radiated.
b. The horizontal or vertical plane of
the electric wave.
c. The direction in which magnetic
wave is radiated.
d. None of these
2. The D, E and F layers of the ionosphere are
called
a. Mark-Space Layers
b. Davidson-Miller Layers
c. Kenelly Heaviside Layers
d. Maxwell Layer
3. ________ refers to the ratio of an electric
field component to a magnetic field
component at the same point of the wave.
a. Characteristics impedance
b. Load impedance
c. Intrinsic impedance
d. Wave impedance
4. The field strength of a radio signal varies
according to the output or transmitted power
and the distance of the receiver from the
transmitter. This wave behavior is described
by
a. The field strength
b. Huygen’s Principle
c. Faraday’s Law
d. Inverse Square Law
5. The antenna theory states that reception and
transmission functions are interchangeable is
a. Poynting Theorem

b. Snell’s Law
c. Huygen’s Principle
d. Law of Reciprocity
6. The frequency band where electromagnetic
waves travel in straight path or in a direct
line of sight between the transmitter and
receiver antenna is
a. ELF
b. HF
c. VLF
d. VHF and above
7. This mode of electromagnetic wave
propagation uses the earth’s surface or
curvature as a guide to transmit vertically
polarized waves
a. Sky wave
b. Tropospheric wave
c. Transionospheric wave
d. Ground wave
8. Frequencies in the UHF range propagate by
means of
a. Ground waves
b. surface waves
c. sky waves
d. space waves
9. the ground wave eventually disappear as it
moves farther away from the transmitter,
because of
a. tilting
b. reflection
c. refraction
d. diffraction
10. as electromagnetic waves travel in free
space, only one of the following can happen
a. absorption
b. attenuation
c. refraction
d. reflection
11. In polarization diversity, two signals are
a. Both polarized at one specific
loacation
b. Vertically and horizontally
polarized separately
c. Polarized in the same manner
d. Vertically and horizontally polarized
using a common antenna
12. If the direction of the electric field of a radio
wave is horizontal. That wave is known to
be _____ polarized.
a. Negatively

b. Vertically
c. Positively
d. Horizontally
13. The property of a material that determines
how much change electrostatic energy can
be stored per unit volume when voltage is
applied
a. Miller effect
b. Permeability
c. Capacitance
d. Permitivity
14. According to this law or principle, a
wavefront may be considered to consist of
an infinite number of isotropic radiators,
each one sending out wavelets, always away
from the source.
a. Snell’s Law
b. Maxwell’s Law
c. Huygen’s Principle
d. Archimedes Principle
15. A number, which when multiplied by the
speed of light in free space gives the speed
of light in the medium in question is
a. Fibonacci number
b. Fermat’s number
c. Velocity factor
d. K-factor
16. The ability of a radio wave to be bent
slightly over the edge of a sharp obstacle
such as a steep hill or mountain top is
a. Diffraction
b. Reflection
c. Refraction
d. Attenuation
17. A space wave is
a. Sky wave
b. Radio wave
c. Surface wave
d. Line of sight propagation wave
18. It is a diagram indicating the intensity in
volts/meter, in all directions, of the radiated
filed of an antenna as it would occur under
actual operating conditions.
a. Constellation diagram
b. Argand diagram
c. Funicular diagram
d. Radiation pattern
19. Equivalent to capacitance in electrical
circuits
a. Inductance
b. Permittivity
c. Permeability

d. Power density
20. All of these cause attenuation except
a. Tilting
b. Ground absorption
c. Atmospheric absorption
d. Surface wave propagation
21. The transmission of radio waves far beyond
line of sight distances by using high power
and large transmitting antennas to beam the
signal upward into the atmosphere and a
similar large receiving antenna to pick up a
small portion of the signal scattered by the
atmosphere is called
a. Forward scatter propagation
b. Beyond the horizon propagation
c. Either a or b
d. Meteoric Scatter Propagation
22. The apparent height of an ionized layer of
the atmosphere; as determined from the time
interval between the transmitted signal and
the ionospheric echo at vertical incidence.
This height is the maximum height reached
if the actual paths are projected forming
straight lines from the ascent to the descent
of waves.
a. Optimum height
b. Virtual height
c. Complex height
d. Critical height
23. The highest frequency whereby a wave will
be returned back to earth by an ionospheric
layer having been beamed up at it and
ranges from 5 to 12 MHz. For F2 layers.
This frequency is directly proportional to the
secant function of the smallest angle, which
allows reflection of sky waves.
a. Apex frequency
b. Critical frequency
c. Carrier frequency
d. Baseband frequency
24. The distant at which sky-wave signals are
reflected back to earth depend on
a. Height of the reflecting layer
b. The takeoff angle of the waves
c. Both a and b
d. Conductivity of the soil
25. Perfect reflection of waves occur when
a. The magnitude of the incident is
equal to the reflected waves
b. The magnitude of the incident is less
than the reflected waves
c. The magnitude of incident is greater

than reflected waves
d. Both and b
26. The process by which a radio wave is bent
and returned to earth from one medium to
another after striking them is
a. Reflection
b. Refraction
c. Diffraction
d. Absorption
27. An incident, traveling obliquely from one
medium to another, will undergo a change in
direction if the velocity of the wave in one
medium is different from that in the other
and the ratio of the sine of the angle of
incidence to the sine of the angle of
refraction is the same ratio of respectively
wave velocities in these media. This law is
called
a. Snell’s Law
b. Fisher’s Law
c. Hooke’s Law
d. Newton’s Law
28. The lowest layer of the ionosphere which
exists between 50 to 90 km from the earth’s
surface and reflects VLF and LF waves
while absorbing MF and HF waves during
daytime is the
a. D layer
b. E layer
c. F layer
d. Vantress layer
29. This phenomenon occurs when the thicker
air is on top instead of being at the bottom
when the temperature of water vapor
gradient is lesser or greater than the standard
rate.
a. Thermal inversion
b. Horizontal ducting
c. Elevated ducting
d. Sporadic E
30. An ionospheric layer, which exists between
90 to 120 km above the earth’s surface and
is about 25km thick. It aids MF surface
propagation while reflecting some HF
during daytime
a. D-layer
b. E-layer
c. F layer
d. Vantress layer
31. Atmospheric condition is controlled by
a. Pressure
b. Temperature

c. Humidity
d. All of these
32. This ionospheric layer forms at night at
about 300 km from the earth’s surface and is
responsible for long distance HF wave
propagation due to reflection and refraction.
It splits during daytime due to the ionizing
energy from ultraviolet rays of the sun.
a. D layer
b. E layer
c. F layer
d. Vantress layer
33. When the transmitting and receiving
antennas are line-of-sight of each other, the
mode of propagation is _____ wave.
a. Space or direct
b. Sky
c. surface
d. ground
34. Power density is inversely proportional to
the square of the distance from the source or
transmitter to the destination or receiver.
This law is called:
a. Coulomb’s law
b. Law of Universal Gravitation
c. Inverse Square Law
d. Lenz’s Law
35. A one-hop, full duplex, microwave system is
in a space diversity arrangement. Determine
how many receivers in all are used?
a. 6
b. 2
c. 8
d. 4
36. ________ is the extra ionization of the Elayer resulting to irregular and intermittent
reflection of frequencies of up to 80 MHz in
temperate and lower latitudes of frequencies
of up to 80MHz in temperate and lower
latitudes. It is variable in time of occurrence,
height. Geographical distribution,
penetration frequency and ionization
density.
a. Sporadic E
b. Dillinger Effect
c. Faraday rotation
d. Scintillations
37. The decrease in signal strength as a result of
absorption or scattering of energy along a
transmission path is called:
a. Attenuation
b. Microbending

c. Dispersion
d. Multipath fading
38. The transfer of electromagnetic waves or
acoustical energy from one place to another
through a suitable transmission medium is
a. Wave propagation
b. RF induction
c. Radio Frequency Interference
d. Forward Scatter
39. The upper limit of frequencies that can be
used at a specified time for radio
transmission between two points and
involving propagation by reflection from
regular ionized layers of the ionosphere is
a. Maximum usable frequency
b. Optimum traffic frequency
c. Minimum usable frequency
d. Carrier frequency
40. Waves whose oscillations are perpendicular
to the direction of propagation are called
a. Huygen’s waves
b. Transverse waves
c. Longitudinal waves
d. Fraunhoffer waves
41. Indicate which one of the following terms
applies to troposcatter propagation:
a. SIDs
b. Fading
c. Atmospheric storms
d. Faraday rotation
42. VLF waves are used for some types of
services because
a. Of the low power required
b. The transmitting antennas are of
convenient size
c. They are very reliable
d. They penetrate the ionosphere easily
43. High frequency waves are
a. Absorbed by the F2 layer
b. Reflected by the D layer
c. Capable of use for long-distance
communications on the moon
d. Affected by the solar cycle
44. Distances near the skip distance should be
used for sky-wave propagation
a. To avoid tilting
b. To prevent sky-wave and upper
ray interference
c. To avoid the faraday effect
d. So as not to exceed the critical
frequency
45. The ground wave ecentually disappears, as

one moves away from the transmitter,
because of
a. Interference from the sky wave
b. Loss of line of sight conditions
c. Maximum single-hop distance
limitation
d. Tilting
46. In electromagnetic waves, polarization
a. Is caused by reflection
b. Is due to the transverse nature of
the waves
c. Results from the longitudinal nature
of the waves
d. Is always vertical in an isotropic
medium
47. Radio fading resulting from obstruction
losses.
a. Log normal fading
b. Rayleigh Fading
c. Multi-path fading
d. None of these
48. The absorption of radio waves by the
atmosphere depends on
a. Their frequency
b. Their distance from the transmitter
c. The polarization of the waves
d. The polarization of the atmosphere
49. Electromagnetic waves are refracted when
they
a. Pass into a medium of different
dielectric constant
b. Are polarized at right angles to the
direction of propagation
c. Encounter a perfectly conducting
surface
d. Pass through a small slot in a
conducting plane
50. Diffraction of electromagnetic waves
a. Is caused by reflection from the
ground
b. Arises only with spherical
wavefronts
c. Will occur when the waves pass
through a large slot
d. May occur around the edge of a
sharp obstacle
51. What do you call of the travel of
electromagnetic waves through a medium at
the speed of light?
a. RF propagation

b. Radio propagation
c. Wave propagation
d. All of these
52. Electromagnetic waves are
a. Consist of electric and magnetic
component that are parallel to each
other
b. Oscillations that propagate
through free space
c. Irregular oscillations
d. Oscillations that are produced by an
oscillating circuit

53. The region around an electrically charged
body in which other charged bodies are
acted by an attracting or repelling force.
a. Electric field
b. Radiation field
c. Magnetic field
d. Electromagnetic field
54. What are the two components of
electromagnetic field?
a. Ray and wavefront
b. Magnet and electricity
c. Polar electrons and magnetic field
d. Electric field (E-field) and
magnetic field
55. Shows a surface of constant phase of a wave
and is formed when points of equal phase on
rays propagated from the source are joined
together.
a. Ray
b. Wavefront
c. Point source
d. Isotropic source
56. It is a line drawn along the direction of
propagation of an electromagnetic wave
used to show the relative direction of
electromagnetic wave propagation.
a. Ray
b. Wavefront
c. Point source
d. Isotropic source
57. Refers to the rate at which energy passes
through a given surface area in free space
a. Field intensity
b. Power density
c. Refractive index
d. Absorption coefficient
58. It it’s the intensity of the electric and

magnetic fields of an electromagnetic wave
propagating in free space
a. Field intensity
b. Power density
c. Refractive index
d. Absorption coefficient
59. In a lossless transmission medium, _______
of free space is equal to the square root of
the ratio of its magnetic permeability to its
electric permittivity
a. Resistance
b. Field intensity
c. Characteristic impedance
d. A or C is correct
60. Electromagnetic wave measures all except
a. Inductance
b. Power density
c. Magnetic field intensity
d. Permittivity of the medium
61. A reduction in power density due to the
inverse square law presumes free-space
propagation is called
a. Absorption
b. Wave attenuation
c. Space attenuation of the wave
d. B or C is correct
62. Which of the following are optical effects of
radio waves?
a. Refraction and reflection
b. Diffraction and interence
c. Induction and diffraction
d. A and B
63. What is diffraction?
a. Is the change in direction of a ray as
it passes obliquely from one medium
to another with different velocities or
propagation
b. Refers to the modulation or
redistribution of energy within a
wavefront when it passes near the
edge of an opaque object
c. Is the phenomenon that allows light
or radio waves to travel(peek)
around corners of an obstacle.
d. A or C is right
64. A rare refracting medium has
a. Smaller value of dielectric constant
b. Higher value of dielectric constant
c. Variable value for dielectric constant
d. A dielectric constant dependent on
the medium
65. Refractive index refers to

a. The ratio of velocity of light in free
space to the velocity of light in a
given material
b. The ratio of the light in free space
towards the light in a given medium
c. The ratio of the angle of refraction
d. The amount of bending or refraction
that occurs at the interface of two
material of different densities

66. Why is it that rays traveling near the top of
the medium travel faster than those at the
bottom?
a. The medium is more dense near the
bottom
b. The medium is less dense at the top
c. A and B are incorporated
d. The medium is less dense near the
bottom and more dense at the top
67. When does reflection if wave occur?
a. When an incident wave strikes a
boundary of two media, and some of
the incident power does not enter the
second material
b. When the reflective surface is
irregular or rough
c. When two or more electromagnetic
waves combine in such a way that
the system performance is degraded.
d. A and B
68. What is meant by specular reflection?
a. Is a reflection from a perfectly
smooth surface
b. Is an incident wavefront striking an
irregular surface, randomly scattered
in many directions
c. Reflection of surfaces that fall
between smooth and irregular
d. Is a combination of diffused and
semirough surfaces
69. ________ states that a semirough surface
will reflect as if it were a smooth surface
whenever the cosine of he angle of
incidence is greater than 1/8d, where d is the
depth of the surface irregularity and I is the
wavelength of the incident wave.
a. Rayleigh criterion
b. Huygen’s principle
c. Linear superposition
d. Reflection coefficient

70. Energy that has neither been radiated into
space nor completely transmitted
a. Modulated waves
b. Captured waves
c. Standing waves
d. Incident waves
71. What property of radio waves occurs
whenever two or more waves
simultaneously occupy the same point in
space?
a. Reflection
b. Refraction
c. Diffraction
d. Interference

72. Pertains to a source which radiates equally
in all directions
a. Isobaric source
b. Isotropic source
c. Isentropic source
d. Isothermal source
73. Electromagnetic waves travel at _____ in
free space
a. 300,000 km/sec
b. 200 km/sec
c. 400,000 km/sec
d. 100,000 km/sec
74. Any space or region wherein a magnetic
force is exerted on moving electric charges
a. Electric field
b. Radiation field
c. Magnetic field
d. Electromagnetic field
75. Which of the following is a characteristic of
electromagnetic wave?
a. Measures power, voltage,
capacitance and impedance of a
system
b. Measures power density, voltage,
and inductance
c. Measures power density, magnetic
field intensity, and electric field
intensity
d. All of the above
76. Reflection waves
a. Should take place at one medium
b. Does not necessarily take place at
one medium
c. Occurs at any other medium at the
same time

d. Is not possible
77. Way(s) of propagating electromagnetic
waves:
a. Ground-wave propagation
b. Space wave propagation
c. Sky-wave propagation
d. All of these
78. At frequencies below 1.5 MHz, what
propagation provides the best coverage?
a. Ground wave
b. Space wave
c. Sky wave
d. All of these
79. Which of these causes the wavefront to tilt
progressively forward?
a. Gradient density
b. Electric field intensity
c. Absorption coefficient
d. Magnetic field intensity
80. Which of following of must be taken into
consideration to ensure proper ground-wave
propagation?
a. Power
b. Terrain
c. Frequency
d. B and C
81. What are the applications of ground–wave
propagation?
a. Ship-to-ship and ship-to-shore
communications
b. Maritime mobile communications
c. Radio navigation
d. All of these
82. The curvature of the earth presents a horizon
to space wave propagation which is
approximately 4/3 that of the optical horizon
a. Standard atmosphere
b. Optical horizon
c. Radio horizon
d. All of these
83. Refraction is caused by what factors?
a. Changes in troposphere’s density and
temperature
b. Water vapor content
c. Relative conductivity
d. All of the above
84. Any of the flowing can be caused to
lengthen radio horizon:
a. Elevating the transmit or receive
antennas above Earth’s surface
b. Elevating both antennas
c. Installing the transmit and/or receive

antennas on top of mountains or high
buildings
d. All of these
85. A special condition which occurs when the
density of the lower atmosphere is such that
electromagnetic waves are trapped between
it and earth’s surface
a. Duct propagation
b. Sky wave propagation
c. Space wave propagation
d. Ground wave propagation

a. D layer
b. E layer
c. F layer
d. G layer
91. A layer in the ionosphere which is the most
important reflecting medium fir HF radio
waves. It has 2 sublayers, at 90 to 250 mi
height
a. A layer
b. D layer
c. E layer
d. F layer

86. The vibrating electrons at the ionosphere
decrease current which is equivalent to
reducing the dielectric constant, which in
turn, will also cause the velocity of
propagation to______.
a. Increase
b. Decrease
c. Remain constant
d. Decrease by a factor of 2
87. Increasing the velocity of propagation
causes a/an _____ of the electromagnetic
waves.
a. Increasing refraction
b. Decreasing reflection
c. Increasing diffraction
d. Decreasing interference
88. What layer has its maximum density at
approximately 70 mi a noon, when the sun is
at its highest point?
a. D layer
b. E layer
c. Kennelly-Heaviside layer
d. B or C
89. The sporadic E layer is a thin layer with a
very high ionization density. It is considered
separately from the other layers and when it
appears, gives an unexpected improvement
in long distance radio transmissions. What
cause(s) its unpredictable appearance?
a. Sunspot activity
b. Sunspot cycle
c. Solar flares
d. A and C
90. The region in the ionosphere with a very
high ionization density at roughly 55 to 90
miles and is used for frequencies up to about
20 MHz. It is gone completely at midnight.

92. The apparent height og the ionized layer and
is always greater than the actual height
a. Critical height
b. Virtual height
c. Maximum height
d. Imaginary height
93. Refers to the shortest distance in which a
sky-wave signal will be returned to the
earth. It includes the maximum ground-wave
range and the width of the skip zone.
a. Hop
b. Skip distance
c. Actual distance
d. Critical distance
94. Concerns to the highest frequency that is
able to return to earth when beamed at a
certain angle of incidence
a. Relative frequency
b. Optimum frequency
c. Resonant frequency
d. Maximum usable frequency, muf
95. In ________, the distant of each succeeding
hop from earth to ionosphere and back is
also the skip distance.
a. Hop transmission
b. Single transmission
c. Unihop transmission
d. Multihop transmission
96. Concerns to the single reflection of a radio
wave form the ionosphere back to earth.
a. Jog
b. Hop
c. Skip
d. Fading
97. The fluctuation of signal strength at the
receiver that are caused by changes in the
transmission medium

a. Fading
b. Hopping
c. Skipping
d. Diversity
98. Gradual variation in the field strength of a
radio signal is compensated by
a. Fading techniques
b. Diversity techniques
c. Transverse techniques
d. Transmission techniques
99. A modulation of two different RF carrier
frequencies with the same IF intelligence,
then transmitting both RF signals to a given
destination.
a. Diversity
b. Space diversity
c. Frequency diversity
d. Polarization diversity
100. To increase the availability of the system, a
method in which the output of a transmitter
is fed to two or more antennas that are
physically separated by an appreciable
number of wavelengths.
a. Space diversity
b. Frequency diversity
c. Polarization diversity
d. Space wave propagation
COMMUNICATIONS ENGINEERING
PART 6
ANTENNAS
1. An ungrounded antenna near the ground
a. Acts as a single antenna of twice the
height
b. Is unlikely to need an earth mat
c. Acts as an antenna array
d. Must be horizontally polarized
2. One of the following consists of nonresonant
antennas:
a. The rhombic antenna
b. The folded dipole
c. The end-fire array
d. The broadside array
3. One of the following is very useful as a
multiband HF receiving antenna. This is the:
a. Conical horn
b. Folded dipole
c. Log-periodic
d. Square loop
4. Which of the following antennas is best
excited from a waveguide?

a. Biconical
b. Horn
c. Helical
d. Discone
5. Indicate which of the following reasons for
using a counterpoise with antennas is false:
a. Impossibility of a good ground
connection
b. Protection of personnel working
underneath
c. Provision of an earth for the antenna
d. Rockiness of the ground itself
6. One of the following is not a reason for the
use of an antenna coupler:
a. To make the antenna look resistive
b. To provide the output amplifier with the
correct load impedance
c. To discriminate against harmonics
d. To prevent reradiation of the local
oscillator
7. Indicate the antenna that is not wideband
a. Discone
b. Folded dipole
c. Helical
d. Marconi
8. Indicate which one of the following reasons
for the use of an earth mat with antennas is
false:
a. Impossibility of a good ground
connection
b. Provision of an earth for the antenna
c. Protection of personnel working
underneath
d. Improvement of the radiation pattern of
the antenna
9. Show which of the following terms does not
apply to the Yagi-Uda array
a. Good bandwidth
b. Parasitic elements
c. Folded dipole
d. High gain
10. An antenna that is circularly polarized is the
a. Helical
b. Small circular loop
c. Parabolic reflector
d. Yagi-Uda
11. The standard reference antenna for the
directive gain is the
a. Infinitesimal dipole
b. Isotropic antenna
c. Elementary doublet
d. Half-wave dipole

12. Top loading is sometimes used with an
antenna in order to increase its
a. Effective height
b. Bandwidth
c. Beamwidth
d. Input capacitance
13. Cassegrain feed is used with a parabolic
reflector to
a. Increase the gain of the system
b. Increase the beamwidth of the system
c. Reduce the size of the main reflector
d. Allow the feed to be places at a
convenient point
14. Zoning is used with a dielectric antenna in
order to
a. Reduce the bulk of the lens
b. Increase the bandwidth of the lens
c. Permit pin-point focusing
d. Correct the curvature of the wavefront
from a horn that is too short
15. A helical antenna is used for satellite
tracking because of its
a. Circular polarization
b. Maneuverability
c. Broad bandwidth
d. Good front-to-back ratio
16. The discone antenna is
a. A useful direction-finding antenna
b. Used as a radar receiving antenna
c. Circularly polarized like other circular
antennas
d. Useful as a UHF receiving antenna
17. One of the following is not omnidirectional
antenna
a. Half-wave dipole
b. Log-periodic
c. Discone
d. Marconi
18. The polarization of a discone antenna is
______________.
a. Horizontal
b. Vertical
c. Omni
d. Directional
19. _____________ is the horizontal pointing
angle of an antenna.
a. Right angle
b. Angle of elevation
c. Bandwidth
d. Azimuth
20. Which is a properly terminated antenna?
a. Rhombic

b. Hertz
c. Marconi
d. Dipole
21. ____________ is a device that detects both
vertically and horizontally polarized signals
simultaneously.
a. Crystal
b. Orthomode transducer
c. Light transducer
d. Optoisolator
22. How much does the radiated power of an
antenna increases if its current increased by
3.3 times?
a. 6.6 times
b. 3.3 times
c. 10.89 times
d. 9.9 times
23. What do you call the energy that was not
radiated into space or completely
transmitted?
a. Incident waves
b. Captured waves
c. Standing waves
d. Modulated waves
24. What is the estimated medium wind loading
in the Philippines for antenna tower design?
a. 200 kph
b. 250 kph
c. 300 kph
d. 100 kph
25. The minimum number of turns a helix
antenna must have
a. 4
b. 5
c. 3
d. 6
26. When testing transmitter to prevent
interfering with other stations, which type of
antenna must be used?
a. Dummy antenna
b. Herztian antenna
c. None
d. Void antenna
27. A device that radiates electromagnetic
energy and/or intercepts electromagnetic
radiation
a. Antenna
b. Transmitter
c. Transmission line
d. Transceiver
28. Determine the gain of a 6 ft parabolic dish
operating at 1800 MHz

a. 15.5 dB
b. 30 dB
c. 11.2 dB
d. 28.17 dB
29. Radiation characteristic of a dipole
a. figure of eight
b. omnidirectional
c. bi-directional
d. unidirectional
30. An antenna which is not resonant at
particular frequencies and so can be used
over a wide band of frequencies is called
a. Aperiodic
b. Cassegrain
c. Top-loaded
d. Boresight
31. Two wires that are bent 90 degrees apart.
a. Rhombic
b. Hertz
c. Dipole
d. Log-periodic
32. Harmonic suppressor connected to an
antenna
a. Tank circuit
b. M-derived filter
c. Low-pass filter
d. High-pass filter
33. Theoretical gain of a Herztian dipole
a. 0 dB
b. 1.76 dB
c. 2.15 dB
d. 3 dB
34. A helical antenna is used for satellite
tracking because of
a. Maneuverability
b. Good front-to-back
c. Circular polarization
d. Broad bandwidth
35. A convenient method of determining antenna
impedance
a. Reactance circle
b. Stub matching
c. Smith chart
d. Trial and error
36. Unity gain antenna.
a. Half-wave dipole
b. Rhombic
c. Dummy
d. Isotropic
37. EIRP stands for ______________________.
a. Effective isotropic reflected power
b. Effective isotropic refracted power

c. Efficient and ideal radiated power
d. Effective isotropic radiated power
38. Which of the following refers to the smallest
beam of satellite antenna’s radiation pattern?
a. Global beam
b. Zoom beam
c. Spot beam
d. Hemispheric beam
39. A region in front of a parabolic antenna
a. Transmission zone
b. Fraunhofer
c. Fresnel
d. All of these
40. An antenna that can only receive a television
signal.
a. Isotropic antenna
b. Reference antenna
c. TVRO
d. Yagi antenna
41. Radiation pattern of a discone
a. Figure of eight
b. Bi-directional
c. Omnidirectional
d. Unidirectional
42. Radio wave concentration in the direction of
the signal emitted by a directional antenna.
a. Back lobe radiation
b. Transmitted signal
c. Side lobe radiation
d. Major lobe radiation
43. The reflector and director of an antenna
array are considered as:
a. Transcendental elements
b. Feed-points
c. Driven elements
d. Parasitic elements
44. An electronic equipment used to measure
standing wave ratio:
a. Altimeter
b. Multimeter
c. Reflectometer
d. Wavemeter
45. The product of the power supplied to the
antenna and its gain relative to a half-wave
dipole in a given direction.
a. Rated power
b. ERP
c. Peak envelope power
d. Carrier power
46. What makes an antenna physicaly long
electronically short?
a. Adding C in series

b. Top loading
c. Adding L in series
d. All of these
47. The capture area of an antenna is directly
proportional to the
a. Distance between transmitter and
receiver
b. Power density of the signal
c. Gain of the antenna
d. Frequency of the received signal
48. A type of an underfrounded antenna is a/an
________________.
a. Hertz
b. Isotropic
c. Parabolic
d. Marconi
49. What is meant by antenna gain?
a. The ratio of the signal in the forward
direction to the signal in the backward
direction
b. The ratio of the amount of power
produced by the antenna compared to the
output power of the transmitter
c. The final amplifier gain minus the
transmission line losses (including any
phasing lines present)
d. The numeric ratio relating the
radiated signal strength of an antenna
to that of another antenna
50. It consists of a number of dipoles of equal
size, equally spaces along a straight line with
all dipoles fed in the same phase from the
same source.
a. End-fire array
b. Yagi antenna
c. Log-periodic antenna
d. Broadside array
51. A type of array antenna which consists of
one half-wave driven dipole, one reflector
and one director.
a. Log periodic dipole array
b. Yagi-uda
c. Herztian dipole
d. Broadside collinear
52. It is measure of the microwave power
radiated from an antenna as a function of
angular direction from the antenna axis.
a. Polarization
b. Sidelobes
c. Beamwidth
d. Antenna pattern
53. What is the gain of four identically polarized

antennas stacked one above the other fed in
phase?
a. 4 dB over the gain of one antenna
b. 10 dB over the gain of one antenna
c. 3 dB over the gain of one antenna
d. 6 dB over the gain of one antenna
54. Gain of an isotropic antenna.
a. 1 dB
b. -1 dB
c. 0 dB
d. 2 dB
55. A dipole antenna requires to be fed with 20
kW of power to produce a given signal
strength to a particular distant point. If the
addition of a reflector makes the same field
strength available with an input power of 11
kW, what is the gain in dB obtained by the
use of the reflector? (Gain referred to this
particular dipole)
a. 4. 75
b. 1.81
c. 4.24
d. 2.6
56. Top loading is used in an antenna in order to
increase its __________________.
a. Bandwidth
b. Beamwidth
c. Input capacitance
d. Effective height
57. A horizontal antenna is
a. Perpendicularly polarized
b. Centrally polarized
c. Horizontally polarized
d. Vertically polarized
58. The frequency of operation of a dipole
antenna cut to length of 3.4 m.
a. 42.9 MHz
b. 53.3 MHZ
c. 38.5 MHz
d. 61.3 MHz
59. Two or more antennas separated by 9
wavelengths are used.
a. Frequency diversity
b. Space diversity
c. Hybrid diversity
d. Polarized diversity
60. A convenient method of determining antenna
impedance.
a. Trial and error
b. Stub matching
c. Smith chart
d. Reactance circle

61. Width measured in degrees of a major lobe
between end of the lobe at which the relative
power is one half (-3 dB) its value from the
peak of the lobe.
a. Radiation
b. Wavelength
c. Bandwidth
d. Beamwidth
62. An increase in the effective power radiated
by an antenna in a certain desired direction
at the expense of power radiated in other
directions.
a. Antenna gain
b. Antenna efficiency
c. Antenna total ratio
d. Antenna back lobe ratio
63. Where does the maximum current and
minimum voltage value on a resonant Hertz
dipole exist?
a. Center of the antenna
b. Ends of the antenna
c. Near the center of the antenna
d. Near the end of the antenna
64. How can the antenna efficiency of a HF
grounded vertical antenna be made
comparable to that of a half-wave antenna?
a. By isolating the coax shield from ground
b. By installing a good ground radial
system
c. By shortening the vertical
d. By isolating the coax shield from ground
65. Known as the technique for adding a series
inductor at or near the center of an antenna
element in order to cancel the capacitive
reactance of an antenna.
a. Reflector
b. Center loading
c. Dipole
d. Loading coil
66. What is meant by the term antenna
bandwidth?
a. The angle between the half-power
radiation points
b. The angle formed between two
imaginary lines drawn through the ends
of the elements
c. The frequency range over which an
antenna can be expected to perform
well
d. Antenna length divided by the number of
elements
67. Where does the voltage node of a half-wave

antenna exist?
a. At feed point
b. Near the feed point
c. Near the center
d. At center
68. This is a flexible vertical rod antenna
commonly used on mobiles.
a. Hertz
b. Ground plane
c. Whip
d. Marconi
69. What is a dummy antenna?
a. A non-directional transmitting antenna
b. An antenna used for hand-held ratio
c. One which is used as a reference for gain
measurements
d. A non-radiating load for a transmitter
used for testing
70. Best description of a collinear and broadside
antenna radiation pattern.
a. Bidirectional
b. Omnidirectional
c. Unidirectional
d. Perfect circle
71. What is a driven element of an antenna?
a. Always the forwardmost element
b. Always the rearmost element
c. The element fed by the transmission
line
d. The element connected to the rotator
72. Antenna which is not properly terminated
a. Whip
b. Non-resonant
c. Isotropic
d. Resonant
73. At the ends of a half-wave antenna, what
values of current and voltage exist compared
to the remainder of the antenna?
a. Minimum voltage and maximum current
b. Maximum voltage and minimum
current
c. Minimum voltage and minimum current
d. Equal voltage and current
74. Refers to a type of beam antenna which uses
two or more straight elements arranged in
line with each other.
a. Whip antenna
b. Yagi antenna
c. Rhombic antenna
d. Dipole antenna
75. What is meant by the term radiation
resistance for an antenna?

a. Losses in the antenna elements and feed
line
b. An equivalent resistance that would
dissipate the same amount of power as
that radiated from an antenna
c. The resistance in the trap coils to
received signal
d. The specific impedance of the antenna
76. Which of the following parts of the radio
receiver represents the component that
extracts the desired RF signal from the
electromagnetic wave?
a. Detector
b. Antenna
c. Crystal
d. AF amplifier
77. Determine the dB of a receiving antenna
which delivers a microvolt signal to a
transmission line over that of an antenna that
delivers a 20 microvolt signal under identical
circumstances.
a. -26 dB
b. 26 dB
c. 3 dB
d. 10 dB
78. What is the term for the ratio of the radiation
resistance of an antenna to the total
resistance of the system?
a. Antenna efficiency
b. Radiation conversion loss
c. Beamwidth
d. Effective radiated power
79. One of the following prevents a transmitter
from emitting a signal that interferes with
other station on frequency during the test.
a. Use of shielded antenna radiator
b. Use of low height antenna
c. Use of dummy antenna
d. Use of grounded antenna
80. In high frequency radio transmission, the
lower the radio frequency the
_______________ of the antenna.
a. Longer the length
b. Bigger the diameter
c. Shorter length
d. Smaller the diameter
81. Which of the following antenna where its
beamwidth is determined by the dimensions
of its lens or reflector?
a. Whip antenna
b. Aperiodic antenna
c. Aperture antenna

d. Long wire antenna
82. What measure will you adopt on the antenna
system of a VHF or UHF mobile
transceivers that has very low height
antenna?
a. Increase transmitter to antenna cable
b. Use directional antenna
c. Check grounding system
d. Provide loading coil
83. In order to have an effective radio antenna,
the design of its radiator must have a
minimum length equivalent to
________________.
a. λ/10
b. λ/4
c. λ/14
d. λ/6
84. What is a parasitic element of an antenna?
a. An element dependent on the antenna
structure for support.
b. A transmission line that radiates radiofrequency energy.
c. An element that receives its excitation
from mutual coupling rather than
from a transmission line.
d. An element-polarized 90 degrees
opposite the driven element.
85. At what position does a maritime ship main
antenna have when it is open circuited and
that any auxiliary is/are connected to the
main receiver?
a. AA
b. Emergency transmitter
c. Direction finder
d. Ground
86. Due to the presence of parallel LC networks
in the trap antenna, one of the following is a
disadvantage of using this kind of antenna.
a. Radiate harmonics
b. Reduce power
c. Reduce beamwidth
d. Allow entry of interference
87. How do you compare the length of the
reflector element of a parasitic beam antenna
with that of its driven element?
a. Same length
b. Reflector element is 5% longer
c. Reflector element is half shorter
d. Reflector element is 5% shorter
88. Which of the following statements refers to a
reason why intelligence signal cannot be
transmitted directly on their frequency?

a. Their frequencies are high and are
susceptible to noise
b. Their frequencies are high and need very
large antennas
c. Their frequencies are low and need
very large antennas
d. Their frequencies are low and need very
small antennas
89. What is the purpose of a certain antenna
component composed of a parallel LC
networks inserted in the antenna called
traps?
a. Cancel the capacitive reactance of an
antenna
b. Enhance directivity
c. Produce resonant system at specific
frequency
d. Provide a multiband operation
90. Refers to the numerical ratio relating to the
radiated signal strength of an antenna to that
of another antenna.
a. Antenna loss
b. Antenna gain
c. Antenna bandwidth
d. Antenna efficiency
91. How much longer or shorter does the length
of the director element of parasitic beam
antenna compared with that of the driven
element?
a. About 5% shorter
b. Around 10% longer
c. One half longer
d. Around 5% longer
92. Refers to the ratio of radiated to reflected
energy.
a. Front-to-back ratio
b. Antenna efficiency
c. Radiation efficiency
d. Signal-to-noise ratio
93. A half-wave dipole antenna
a. Hertz
b. Marconi
c. Parabolic
d. Vertical monopole
94. When conductors are spread out in a straight
line to a total length of one-quarter
wavelength, the antenna is called what?
a. Marconi
b. Vertical monopole
c. Quarter-wave dipole
d. All of these
95. What do you call of a polar diagram or graph

representing field strengths or power
densities at various angular positions relative
to an antenna?
a. Venn diagram
b. Figure-8 pattern
c. Lissajous figure
d. Radiation pattern
96. ________________ is the ratio of the front
lobe power to the back lobe power.
a. Front-to-side ratio
b. Front-to-back ratio
c. Back-to-front ratio
d. Minor-to-major ratio
97. It is defined as the area within a distance
D2/λ from the antenna, where λ is the
wavelength and D is the antenna diameter in
the same units.
a. Far field
b. Near field
c. Green field
d. Radiation field
98. What is the ratio of the power radiated by
the antenna to the total input power?
a. Power gain
b. Directive gain
c. Antenna efficiency
d. Radiation efficiency
99. _________________ of an antenna refers to
the orientation of the electric field radiated
from it.
a. Radiation
b. Bandwidth
c. Beamwidth
d. Polarization
100. Pertains to a wire structure placed below the
antenna and erected above the ground. It is a
form of capacitive ground system.
a. Image
b. Counterpoise
c. Antenna orientation
d. Antenna polarization
COMMUNICATIONS ENGINNERING
PART 7
MICROWAVES
1. Indicate which of the following frequencies
cannot be used for reliable beyond-thehorizon terrestrial communications without
repeaters:
a. 20 kHz

2.

3.

4.

5.

6.

7.

8.

9.

b. 15 MHz
c. 900 MHz
d. 12 GHz
A ship-to-ship communications system is
plagued by fading. The best solution seems
to be the use of
a. A more directional antenna
b. A broadband antenna
c. Frequency diversity
d. Space diversity
A range of microwave frequencies more
easily passed by the atmosphere than are
the others is called a
a. Window
b. Critical frequency
c. Gyro frequency range
d. Resonance in the atmosphere
Frequencies in the UHF range propagate by
means of
a. Ground waves
b. Sky waves
c. Surface waves
d. Space waves
Tropospheric scatter is used with
frequencies in the following range:
a. HF
b. VHF
c. UHF
d. VLF
When microwave signals follow the
curvature of the earth, this is known as
a. The Faraday effect
b. Ducting
c. Tropospheric scatter
d. Iosnospheric reflection
Helical antennas are often used for satellite
tracking at VHF because of
a. Troposcatter
b. Superrefraction
c. Ionospheric refraction
d. The Faraday effect
_______________ consists basically of a
thin film strip in intimate contact with one
side of a flat dielectric substrate, with a
similar thin-film ground plane conductor on
the other side of the substrate.
a. Strip line
b. Lecher wire
c. Microstrip
d. Stub
Waveguide is a
a. Device used to determine the

wavelength of a signal
b. Hollow metal tube used for
transmission of microwave energy
c. Plastic tubular transmission line for
high RF network
d. Braided wire used for transmission of
HF
10. Transmission lines which can convey
electromagnetic waves only in higher order
modes are usually called
a. Coaxial cable
b. Twisted pair
c. Power lines
d. Waveguides
11. In order to reduce cross-sectional
dimensions, the waveguide to use is
a. Circular
b. Ridge
c. Rectangular
d. Elliptical
12. A signal propagated in a waveguide has a
full wave of electric intensity change
between the two farther walls, and no
component of the electric field in the
direction of propagation. The mode is
a. TE1,1
b. TE1,0
c. TM2,2
d. TE2,0
13. When a particular mode is excited in a
waveguide, there appears an extra electric
component, in the direction of propagation.
The resulting mode is
a. Transverse electric
b. Transverse magnetic
c. Longitudinal
d. Transverse electromagnetic
e. None of these
14. The wavelength of a wave in a waveguide
a. Is greater than in free space
b. Depends on waveguide dimensions and
free space wavelength
c. Is inversely proportional to the phase
velocity
d. Is directly proportional to the group
velocity
15. When electromagnetic waves are
propagated in a waveguide, they
a. Travel along the broader walls of the
guide
b. Are reflected from walls but not
travel along them

c. Travel through the dielectric without
touching the walls
d. Travel along the 4 walls of the
waveguides
16. When microwave signals follow the
curvature of the earth, this is known as
a. Faraday Effect
b. Deducting
c. Tropospheric Scatter
d. Ionospheric Reflection
17. A waveguide mode in which there is no
component of electric field in the direction
of propagation given in the British
European standards.
a. H-mode
b. E-mode
c. TE mode
d. M-mode
18. The extra strength needed in order to assure
that enough signal reaches the receiving
antenna and must be made available to
compensate for fades; computed as the
difference between the received signal
strength and the threshold level
a. Fade Margin
b. Threshold Level
c. Noise Figure
d. RSL
19. The use of redundant system to reduce the
effects of multipath fading is
a. Combining
b. Modulation
c. Multiplexing
d. Diversity
20. A profile graph of the microwave energy
path
a. Shows the cross section of the earth’s
surface
b. Determines LOS or site technical
feasibility
c. Determines the actual clearance,
antenna heights and system reliability
d. All of the preceding
21. In locating microwave relay stations, the
systems designer must consider
a. Terrain obstructions and reflection
points
b. Site security and navigational hazards
c. Availability of power, water source and
accessible roads
d. All of the above
22. A microwave path over which radio waves

barely touches the obstruction is called
a. Line of Sight
b. Obstructed Path
c. Grazing Path
d. Crooked Path
23. What is the function of regenerative
repeater?
a. To eliminate bias distortion
b. To help in the loading of the telegraphs
lines
c. To reduce required signal levels
d. To reshape the pulses after they have
become distorted
24. A situation when there is no change in
attenuation or “no gain, no loss” occurs
when ________ % of the first Fresnel
radius clears a path obstruction in
microwave systems.
a. 45%
b. 60%
c. 75%
d. 85%
25. ____________ are concentric circular
zones about a direct path of a microwave
signal called Huygen’s radiation center,
forming an imaginary solid called an
ellipsoid __________.
a. Temperature zone
b. Skip zone
c. Fresnel zone
d. Fraunhoffer zone
26. Waveguides are used mainly for microwave
transmission because
a. They depend on straight line
propagation
b. Losses are heavy at lower frequencies
c. They are bulky at lower frequencies
d. No generator is powerful enough to
excite them
27. A waveguide assembly that lets the radar
transmitter and receiver share an antenna is
called
a. Translator
b. Diplexer
c. Flip-flop
d. duplexer
28. ________________ is a graph wherein the
terrain in which the microwave beam
should traverse.
a. Topograph
b. Radio path profile
c. Fresnel graph

d. Net path graph
29. The Fresnel zone is the circular zone about
the _______ path.
a. Reflected
b. Direct
c. LOS
d. Refracted
30. The radius in the circular zone is in the first
Fresnel zone when the reflected path is
_______ longer than the direct path.
a. λ/2
b. λ
c. λ/4
d. λ/8
31. At __________ of the first Fresnel zone is a
condition where there is no gain and no
loss.
a. 0.5
b. 0.6
c. 0.7
d. 0.8
32. The weakest signal the receiver could
accept to be considered satisfactory.
a. Threshold
b. Fade margin
c. RSL
d. NPL
33. The frequency band from 8 to 12 GHz is
known as the band.
a. C
b. Ku
c. X
d. Ka
34. The difference between the Received
Signal Level and the FM Improvement
Threshold
a. System Gain
b. Noise Threshold
c. Fade Margin
d. Reliability
35. A Fade Margin of 28 dB has a reliability of
a. 99%
b. 99.9%
c. 99.99%
d. 99.999%
36. Topographical maps are used for
microwave communications systems design
because _________ are shown, thereby
elevations are known.
a. Latitudes
b. Longitudes
c. Contour lines

d. Scales
37. The dominant mode in a rectangular
waveguide.
a. TEM
b. TE1,1
c. TE1,0
d. TM1,1
38. The velocity of a resultant wave as it
travels through the waveguide.
a. Speed of light
b. Group velocity
c. Phase velocity
d. Incident velocity
39. The principal mode for a circular
waveguide.
a. TE1,0
b. TM2,0
c. TE1,1
d. TEM
40. A type of waveguide that reduces the
cutoff wavelength, increases bandwidth and
allows for a variation of the characteristics
impedance.
a. Ridge
b. Rectangular
c. Tee
d. Twisted
41. The subscript which indicates the number
of λ/2’ s along the waveguide height.
a. m
b. n
c. a
d. b
42. The international equivalent of the TE
mode
a. H
b. E
c. Z
d. TEM
43. The smallest free space wavelength that is
just unable to propagate in the waveguide
under given conditions.
a. Guide
b. Phase
c. Cut-off
d. Group
44. The characteristic wave impedance of a
waveguide in the TE mode is _______ that
of the TM mode.
a. Equal to
b. Higher than
c. Lower than

d. NOTA
45. The following are methods of exciting
waveguides except
a. Slot coupling
b. Antennas
c. Flanges
d. Direct coupling
46. Higher order mode-waveguides are not
used in practice because they have ______
cut-off frequencies.
a. Low
b. High
c. Indeterminate
d. Fixed
47. Indicate which of the following cannot be
followed by the word “waveguide”
a. Elliptical
b. Flexible
c. Coaxial
d. Ridged
48. A piston attenuator is a
a. Vane attenuator
b. Waveguide below cut-off
c. Mode filter
d. Flap attenuator
49. Which of the following waveguide tuning
components is not easily adjustable?
a. Screw
b. Stub
c. Iris
d. Plunger
50. Which of the following is not a waveguide
termination component?
a. Tapered pyramid
b. Post
c. Tapered resistance card
d. Stepped resistance card
51. What microwave component can sample
part of the power travelling through the
waveguide?
a. Directional coupler
b. Magic tee
c. Circulator
d. Re-entrant cavity
52. The following are gases used for LASER’s
except
a. Helium
b. Neon
c. Argon
d. ruby
53. Also known as the optical maser
a. Ruby maser

b. LASER
c. Quantum mechanics
d. GaAs maser
54. Paramagnetic means _____________
magnetic
a. Almost
b. Fully
c. Slightly
d. Electro
55. Tuning the ruby maser is done by adjusting
the _________ to alter the energy level of
the ferrous chromium.
a. Electric field
b. Magnetic field
c. Pumping of electrons
d. Electromagnetic field
56. To overcome the very narrow bandwidth in
ruby maser, _______ is used.
a. Magnetron
b. TWT
c. IMPATT diode
d. Gunn diode
57. The following are applications of masers
except
a. Radioastronomy
b. Radiotelescope
c. Radar
d. ET communications
58. A parametric amplifier is a device which
amplifies signal by varying the
a. Resistance
b. Reactance
c. Magnetic field
d. Electric field
59. The following are parts of the parametric
amplifier except
a. Idling circuit
b. Pump circuit
c. Tuned circuit
d. Filter circuit
60. The number of cavities in a magnetron used
in practice.
a. 4
b. 6
c. 8
d. 10
61. Changing the anode voltage to change the
velocity of the electrons in a magnetron
tube
a. Frequency pushing
b. Frequency pulling
c. Strapping

d. Pumping
62. The lowest frequency that will propagate
through the waveguide while operating in a
particular mode.
a. Critical frequency
b. Cut-off frequency
c. MUF
d. UHF
63. The mode of a waveguide where there is no
component of magnetic field in the
direction of propagation
a. TE
b. TM
c. H
d. TEM
64. The following are slow wave structures
used to retard the RF field in a TWT except
a. Helix
b. Attenuator
c. Waveguide coupled cavity
d. NOTA
65. A rectangular waveguide is 5.1 cm by 2.4
cm. The cut-off frequency for the dominant
mode is
a. 2.94 GHz
b. 6.25 GHz
c. 664 MHz
d. 57.7 GHz
66. Calculate the cut-off wavelength, the guide
wavelength and the characteristic
impedance of a circular waveguide whose
internal diameter is 4 cm for a 10 GHz
signal propagated in it in the dominant
mode. (kr=1.84)
a. 6.83 cm, 3 cm, 420ῼ
b. 3 cm , 6.83 cm, 420 ῼ
c. 6.83 cm, 3.34 cm, 420 ῼ
d. 6.83 cm, 3.34 cm, 338 ῼ
67. A wave is propagated in a parallel plane
waveguide. The frequency is 6 GHz and the
plane separation is 3 cm. The cut-off
wavelength for the dominant mode, the
group and phase velocities are
a. 5 cm, 166 Mm/sec,543 Mn/sec
b. 6 cm, 166 Mm/sec,543 Mn/sec
c. 6 cm, 543 Mm/sec,166 Mn/sec
d. 5 cm, 543 Mm/sec,166 Mn/sec
68. If the MTBF of a communication circuit is
20,000 hours and its MTTR is 5 hours,
what is its unavailability?
a. 0.00025
b. 99.975%

c. 0.25 %
d. 00.975%
69. What would be the ERP, in watts if the
transmitter output is 30 dBm and the
transmission line loss is 20 dB and the
antenna connected to it has a power gain of
60 dB?
a. 10,000 watts
b. 1000 watts
c. 100 watts
d. 10 watts
70. Also referred to as the Transferred Electron
Device
a. Magnetron
b. TWT
c. Gunn diode
d. APD
71. Also known as the Esaki diode
a. Gunn
b. Tunnel
c. IMPATT
d. PIN diode
72. The following are negative resistance
amplifiers except
a. Tunnel
b. Gunn
c. IMPATT
d. PIN diode
73. Regarded as the oldest semiconductor
device
a. Shottky Barrier diode
b. PIN diode
c. Point contact diode
d. Triode
74. Also called the hot electron diode
a. PIN diode
b. ESBAR
c. APD
d. Gunn diode
75. Also called tunnel rectifiers
a. Backward diode
b. Schottky barrier diode
c. APD
d. PIN diode
76. Varactors are variable __________ diode.
a. Reactance
b. Capacitance
c. Inductance
d. Resistance
77. Diodes designed to store energy in their
capacitance during forward bias and
generates harmonics in the reverse bias.

a. Step recovery
b. Gunn
c. APD
d. IMPATT
78. A cross between the TWT and the
magnetron in its operation
a. CFA
b. BWO
c. EIA
d. Twystron
79. The following are parts of a multicavity
klystron except
a. Buncher cavity
b. Catcher cavity
c. Cathode
d. Attenuator
80. The very first microwave transistors
a. GaAs FET
b. Si BJT
c. MIC
d. NOTA
81. The most common microwave FET which
is also known as the MESFET
a. Dual GaAs FET
b. Si BJT
c. MIC
d. Schottky Barrier Gate
82. It looks like a shorter, thicker TWT
a. CFA
b. BWO
c. EIA
d. Twystron
83. A Twystron is a hybrid combination of
a. TWT and Magnetron
b. TWT and Klystron
c. TWT and Ubitron
d. TWT and gyrotron
84. A multicavity klystron with interconnected
multigap cavities
a. TWT
b. Twystron
c. EIA
d. Gyrotron
85. SAW propagate in
a. GaAs
b. InP
c. Stripline
d. Quartz crystal
86. The output from a laser is monochromatic;
this means that it is
a. Infrared
b. Narrow beam

c. Polarized
d. Single frequency
87. The ruby laser differs from the ruby maser
in that the former
a. Does not require pumping
b. Needs no resonator
c. Is an oscillator
d. Produces much lower powers
88. The transmission system using two ground
planes
a. Microstrip
b. Elliptical waveguide
c. Parallel wire line
d. Stripline
89. A BWO is based on the
a. Rising sun magnetron
b. CFA
c. Coaxial magnetron
d. TWT
90. One of the following is unlikely to be used
as a pulsed device
a. Multicavity klystron
b. BWO
c. CFA
d. TWT
91. A microwave tube amplifier uses an axial
magnetic field and a radial electric field
a. Reflex klystron
b. Coaxial magnetron
c. TW magnetron
d. CFA
92. The attenuator is used in the TWT to
a. Help bunching
b. Prevent oscillation
c. Prevent saturation
d. Increase gain
93. The glass tube of a TWT may be coated
with aquadag to
a. Help focusing
b. Provide attenuation
c. Improve bunching
d. Increase gain
94. The cavity magnetron uses strapping to
a. Prevent mode jumping
b. Prevent cathode back heating
c. Ensure bunching
d. Improve the phase focusing effect
95. Compared with equivalent transmission
lines, 3-GHz waveguides (indicate false
statement)
a. Are less lossy
b. Can carry higher powers

c. Are less bulky
d. Have lower attenuation
96. Indicate the false statement. When the freespace wavelength of a signal equals the cutoff wavelength of the guide
a. The group velocity of the signal
becomes zero
b. The phase velocity of the signal
becomes infinite
c. The characteristic impedance of the
guide becomes infinite
d. The wavelength within the waveguide
becomes infinite
97. A disadvantage of microstrip with respect
to stripline circuits is that the former
a. Do not lend themselves to printedcircuit techniques
b. Are more likely to radiate
c. Are bulkier
d. Are more expensive and complex to
manufacture
98. In order to couple two generators to a
waveguide system without coupling them
to each other, one could not use a
a. Rat-race
b. E-plane T
c. Hybrid ring
d. Magic T
99. A PIN diode is
a. A metal semiconductor point-contact
diode
b. A microwave mixer diode
c. Often used as a microwave detector
d. Suitable for use as a microwave
switch
100. For handling high powers, the best
transmission medium is
a. Stripline
b. Microstrip
c. Rectangular waveguide
d. Coaxial line
COMMUNICATIONS ENGINEERING
PART 8
SATELLITE COMMUNICATIONS
1. The first duplex satellite is
a. Moon
b. Sputnik 1
c. Telstar
d. Early Bird
2. The FDMA technique wherein voice band

3.

4.

5.

6.

7.

8.

9.

channels are assigned on “as needed” basis.
a. PAMA
b. DAMA
c. SSMA
d. CDMA
A form of CDMA where a digital code is
used to continually change the frequency of
the carrier.
a. Spread Spectrum
b. Frequency Hopping
c. Store and Forward
d. SPADE
The satellite frequency reuse method which
sends different information signals using
vertical or horizontal electromagnetic
polarization.
a. Multiple coverage areas
b. Dual polarization
c. Spatial separation
d. Spread spectrum
A satellite communication link between
Pinugay Earth Station, Philippines and Mt.
Fucino Earth Station, Italy is to be
established. If the assigneduplink frequency
at Pinugay Earth Station is 6175 MHz, what
is the downlink frequency at Mt. Fucino
Earth Station, in MHz?
a. 4545
b. 3950
c. 3789
d. 4200
A satellite equipped with electronic devices
to receive, amplify, convert and retransmit
signals.
a. Passive
b. Active
c. Uplink
d. Downlink
“The orbit of any planet is an ellipse with
the sun at one focus”. This is
a. Kepler’s First Law
b. Kepler’s Second Law
c. Kepler’s Third Law
d. Law of Universal Gravitation
The point in an satellite orbit which is
farthest away from the earth
a. Perigee
b. Apogee
c. Azimuth
d. Ascending node
The first active satellite which transmitted
telemetry information

a. Telstar 1
b. Aguila II
c. Palapa A 1
d. Sputnik
10. The portion of the satellite communication
link involving the transmission of traffic
from ground station to satellite.
a. Uplink
b. Lowlink
c. Paylink
d. Bus transmission
11. It is spacecraft places in orbit around the
earth carrying on-board microwave
receiving and transmitting equipment.
a. Communication satellite
b. Terrestrial link
c. Transponder
d. Microwave repeater
12. Satellite position has an/a ___________
angle with respect to the horizon.
a. Azimuth
b. Depression
c. Elevation
d. Critical
13. A satellite that revolves from North to
South.
a. Equatorial
b. Polar
c. Orbital
d. Inclined
14. The Kepler’s Law which is also known as
the Law of Areas.
a. First Law
b. Second Law
c. Third Law
d. None of the above
15. The satellite multiple access technique
which uses the spread spectrum technology
is
a. FDMA
b. TDMA
c. CDMA
d. DAMA
16. The point where the orbit crosses the
equatorial plane going from South to North.
a. Ascending Node
b. Descending Node
c. Apogee
d. Perigee
17. The footprint which covers approximately
one-third of the earth’s surface using a 17
degree beamwidth.

a. Spot coverage
b. Zonal coverage
c. Earth coverage
d. Regional coverage
18. An earth station transmits signal to a
satellite 38,500 km., directly overhead it.
What is the propagation delay when the
signal is received back at the same earth
station, in milliseconds.
a. 257
b. 200
c. 285
d. 185
19. When a satellite orbits in the opposite
direction as the earth’s rotation with an
angular velocity less than that of the earth.
a. Bus transmission
b. Payload
c. Prograde
d. Retrograde
20. The actual user information conveyed
through the satellite system.
a. Bus transmission
b. Payload
c. Prograde
d. Retrograde
21. The spatial separation between
geosynchronous satellites
a. 1 – 3 degrees
b. 3 – 6 degrees
c. 6 – 8 degrees
d. 8 – 10 degrees
22. _______________ detects the satellite signal
relayed from the feed and converts it to an
electric current, amplifies and lower its
frequency.
a. Feedhorn
b. Satellite dish
c. Satellite receiver
d. LNB
23. What kind of battery panels are used in
some advance satellites?
a. Gallium Arsenide solar panel
b. Silicon based panels
c. Germanium based panels
d. Gallium Phosphate solar panel
24. Footprint refers to coverage area in the
globe
a. Satellite radiation polarization
b. Satellite navigation
c. Satellite radiation pattern
d. Satellite coverage

25. Satellite system or part of a satellite system,
consisting of only one satellite and the
operating earth station.
a. Satellite system
b. Satellite network
c. Space system
d. Multi-satellite link
26. Known to be the first satellite capable to
receive and transmit simultaneously.
a. Syscom I
b. Echo I
c. Telstar I
d. Score
27. A satellite receives an uplink frequency of
____________ MHz from a ground station
of 3700 MHz.
a. 8150 MHz
b. 1475 MHz
c. 2225 MHz
d. 5925 MHz
28. What band does VSAT first operate?
a. X-band
b. C-band
c. Ku-band
d. L-band
29. Satellite engine use
a. Liquid fuel
b. Jet propulsion
c. Ion propulsion system
d. Solar jet
30. The first passive satellite transponder
a. Early bird
b. Score
c. Moon
d. Sputnik
31. Satellite used for intercontinental
communications are known as
a. Comsat
b. Domsat
c. Marisat
d. Intelsat
32. AsiaSat 1 covers how many countries in
Asia?
a. 38
b. 40
c. 44
d. 42
33. An area on the surface of the earth within
which the boresight of the steerable satellite
beam intended to be pointed.
a. Equivalent boresight area
b. Contour boresight area

c. Coordination boresight area
d. Effective boresight area
34. Refers to the man-made body sent into
continuous orbit around the earth, which
provides propagation paths for radio waves
between terrestrial transmitters and
receivers.
a. Rocket
b. Allotter relay
c. Space shuttle
d. Communication satellite
35. What is the basic function of a
communications satellite?
a. To act as a receiving antenna for
broadcast FM
b. To compensate for the antenna
limitations
c. To eliminate aerodynamic drag
d. To acts as receiving antenna for
broadcast AM
36. Typical round-trip distance and transmission
time for a satellite relay
a. About 300 ms and 90,000 km,
respectively
b. 90,000 km and about 300 ms,
respectively
c. 90,000 mi and about 100 ms,
respectively
d. 90,000 mi and 300 ms, respectively
37. The figure of a satellite defines in orbit
a. Circle
b. Elliptical
c. Parabolic
d. Hyperbolic
38. Considered as the corrupting influence(s) in
the satellite movement.
a. Gravitational pill between the earth and
the orbiting satellite
b. Atmospheric drag on the satellite
c. Orbital ellipse
d. All of these
39. The orbit of communications satellites id
defined by the angle with respect to the earth
equator, which is the 0o plane. What is (are)
the basic orbital angle(s)?
a. Polar
b. Inclined
c. Equatorial
d. All of the above
40. How do we measure the position of a
satellite?
a. By its elevation angle with respect to the

horizon
b. By its azimuth angle measured
clockwise from the direction of true
north
c. Through the line of apsides
d. A and B are correct
41. Which of the following cause(s) the
satellite’s orbital distortions?
a. Sun
b. Earth
c. Moon
d. All of the above
42. What is the approximate service life of
communications satellites?
a. 3 years only
b. 5 to 20 years
c. 20 to 60 years
d. 100 years
43. Representing application of the
extraordinary advances technology of
satellites to solve the problem of accurate,
reliable, 26 hr/day navigation.
a. Global Positioning System (GPS)
b. Navigation System using Timing and
Ranging (NAVSTAR)
c. A and B are correct
d. LORAN
44. A system based on the accurate knowledge
by the vessel of the position of each of four
satellites, as calculated by the time with
respect to the user.
a. GPS
b. A or D
c. LORAN
d. NAVSTAR
45. Segment(s) of a complete GPS system
is(are)
a. Control segment
b. Space segment
c. User segment
d. All of these
46. Its function assures the overall system
performance and accuracy
a. Control segment
b. Space segment
c. User segment
d. All of these
47. The user segment is used to received signals
for the GPS system from the four satellites,
compute the time differences, and determine
position, while space segment’s function
is(are)

a. To received signals for the GPS system
from the four satellites, compute the
distance differences, and determine
position
b. To transmit time codes and orbital
position information to the users
c. To assure the overall performance and
accuracy
d. All of the above
48. How do you describe the complete signal
path of the satellite communications
operation?
a. Begins at a ground station, proceeds to
an uplink, then to a downlink, and ends
at a receiving ground station.
b. From the satellite, to a downlink, tehn to
a ground station.
c. Begins at a ground station, proceeds to
an uplink, to the satellite itself, to a
downlink, and ends at a receiving
ground station
d. All of these
49. What is a passive satellite?
a. A satellite capable of receiving,
amplifying, and retransmitting
information to and from earth stations.
b. A bent-pipe or a reflector which
bounces a signal from one place to
another.
c. A satellite which receives transmissions
from earth stations, stored them on
magnetic tape, and rebroadcast them to
ground stations farther along in its orbit.
d. A or C
50. How does communication between satellite
be achieved
a. Using satellite cross-links
b. Intersatellite links (ISLs)
c. Through is ground stations
d. A or B is correct
51. Which of the following refers to a delayed
repeater satellite?
a. A satellite capable of receiving,
amplifying, and retransmitting
information to and from earth stations.
b. A bent-pipe or a reflector which bounces
a signal from one place to another.
c. A satellite which receives
transmissions from earth stations,
stored them on magnetic tape, and
rebroadcast them to ground stations
farther along in its orbit.

d. All of these
52. Satellite orbiting in the same direction as
earth’s rotation and at an angular velocity
greater than the earth is called prograde
orbit; and a satellite orbiting which is in the
opposite direction as Earth’s rotation or in
the same direction but at an angular velocity
less than that of Earth is known as
a. Haley’s orbit
b. Elliptical orbit
c. Equatorial orbit
d. Retrograde orbit
53. Are satellites that orbit in a circular pattern
with an angular velocity equal to that of
earth.
a. Geostationary or geosynchronous
satellite
b. Nonsynchronous satellite
c. Orbital satellites
d. B or C is correct
54. What do you call of a satellite used to
provide satellite services within a single
country?
a. Orbital satellite
b. Geostationary satellite
c. Nonsynchronous satellite
d. Domestic satellite or domsat
55. Which of the following is not an advantage
of geosynchronous orbit?
a. No need to switch from one satellite to
another as satellites orbit overhead,
therefore, no breaks of transmission due
to switching times.
b. High-altitude geosynchronous satellites
can cover a much larger area
c. Geosynchronous satellites require
higher transmit powers and more
sensitive receivers because of the
longer distances and greater path loss.
d. Satellite remains almost stationary in
respect to a given earth station,
therefore, expensive tracking equipment
is not required at the earth stations.
56. Which of the following parameters (height
of the satellite from earth, travel time,
rotation period, and the satellite’s line of
sight) refer to low-altitude satellite?
a. 19,000 – 25,000 mi; 6,879 mi/hr; 24 hr;
and 24-h availability time, respectively
b. 6,000 – 12,000 mi; 12,189 mi/hr; 5 – 12

hr; and 2- 4 hr per orbit, respectively
c. 100 – 300 mi; 17,500 mi/hr; 1 ½ hr,
and ¼ or less per orbit, respective
d. 50 – 95 mi; 25,600 mi/hr, ½ hr; and 1/8
or less per orbit, respectively
57. There are two primary classifications of
communications satellite; one uses the
angular momentum of its spinning body to
provide roll and yaw relative to earth’s
surface while an internal subsystem provides
roll and yaw stabilization. What are they?
a. gyroscopic satellites
b. delayed repeater satellites
c. passive and active satellites
d. spinners and three-axis stabilizer
satellites
58. How do radiation patterns or beams from a
satellite antenna categorized?
a. Spot
b. Earth
c. Zonal
d. All of these
59. A ____________ satellite with an orbital
period of one sidereal day or nominally, 24 h
a. Bent-pipe satellite
b. Processing satellite
c. Geostationary satellite
d. ANIK-D communications satellite
60. 19,000 – 25,000 mi height; 6, 879 mi/hr
travel time; 24-hr rotation; and 24-hr
availability time belong to what satellite?
a. Low-altitude satellites (circular orbit)
b. Medium-altitude satellites (elliptical
orbit)
c. High-altitude satellites
(geosynchronous orbit)
d. GLONASS
61. An orbit when the satellite rotates in a path
above the equator.
a. Polar orbit
b. Inclines orbit
c. Equatorial orbit
d. Geosynchronous orbit
62. Orbiting satellite system in Russia which
means “lightning” or “news flash”, used for
television broadcasting. It uses a highly
inclined elliptical orbit with apogee at about
40,000 km and perigee at about 1,000 km.
a. Molniya system
b. Molnya system
c. Molnia system
d. All are correct

63. Polar and inclined orbits refer to what?
a. Any other orbital path, and rotation
above the equator, respectively
b. Any other orbital path, and rotation that
takes over the north and south poles,
respectively
c. Rotation that takes over the north and
south poles, and any other orbital
path, respectively
d. Rotation above the equator, and rotation
that takes over the north and south poles,
respectively
64. ____________ means the farthest distance
from earth a satellite orbit reaches while
____________ is the minimum distance.
a. Apogee and perigee, respectively
b. Perigee and apogee, respectively
c. A and B are the same
d. None of these
65. Refers to the line joining the perigee and
apogee through the center of the earth
a. Line of sight
b. Line of nodes
c. Equatorial nelt
d. Line of apsides
66. The point where the orbit crosses the
equatorial plane going from north to south;
and the point where the orbit crosses the
equatorial plane going from south to north
refer to
a. Ascending node
b. Descending node
c. Ascending node and descending node,
respectively
d. Descending node and ascending node,
respectively
67. What is the line joining the ascending and
descending nodes through the center of the
earth?
a. Line of apsides
b. Line of nodes
c. Line of shoot
d. Line of sight
68. Refers to the horizontal pointing of an
antenna.
a. Look angle
b. Elevation
c. Azimuth
d. Spot
69. What is meant by the angle of elevation?
a. The angle formed between the direction
of travel of a wave radiated from an

earth station antenna and the horizontal.
b. The horizontal pointing of an antenna
c. The angle subtended at the earth station
antenna between the satellite and the
horizontal
d. A or C is right
70. The range of frequencies used by
communications satellites?
a. From 1 GHz up to 3 GHz
b. From 1 GHz up to 30 GHz
c. From 30 GHz up to 300 GHz
d. From 300 GHz up to 350 GHz
71. Otherwise considered as radio repeater in
the sky.
a. Transponder
b. Satellite
c. Sputnik
d. Courier
72. How does interference between uplink and
downlink signals be prevented?
a. By using different ground stations
b. By using different satellites
c. By using different carrier frequencies
d. All of these
73. An electronic system called transponder of
the communications satellite is used
a. For frequency translations
b. To retransmit signals
c. To receive signals
d. All of the above
74. What do you call of the signal path from the
transmitter to satellite and from the satellite
to earth-based receiver?
a. Downlink and uplink, respectively
b. Downlink
c. Uplink and downlink, respectively
d. Uplink
75. Why is it that the uplink is always higher in
frequency than the downlink?
a. Because the uplink suffers greater
spreading or free-space loss of frequency
than its lower counterpart
b. Since an earth station aims upward with
well-controlled antenna sidelobes
c. A and B are correct
d. None of these
76. What is frequency hopping?
a. A form of CDMA where a digital code is
used to continually change the frequency
of the carrier
b. Available bandwidth is partitioned into
smaller frequency bands and the total

transmission time is subdivided into
smaller time slots
c. Each earth stations within a CDMA
network is assigned a different
frequency hopping pattern in which each
transmitter hops or switched from one
frequency band to the next according to
their assigned pattern
d. All of these
77. What is meant by satellite footprint?
a. Is the earth area that the satellite can
receive from or transmit to
b. Is the function of both the satellite orbit
and height, and the type of antenna the
satellite uses.
c. The geographical representation of the
satellite antenna’s radiation pattern.
d. All of the above
78. What (is)are the advantage(s) using 1-GHz
and higher frequencies?
a. Large amount of information can be sent
due to large available bandwidth
b. Propagation characteristics are very
consistent
c. Signal wavelengths are shorter
d. All of these are correct
79. What is meant by link budget?
a. The sum of all the signal gains and
losses along the way.
b. The difference of the signal gains and
losses along the way
c. Identifies the system parameters and is
used to determine the projected C/N and
Eb/No ratios at both the satellite and earth
stations receivers for a given modulation
scheme and desired Pq.
d. A or C is right
80. How can satellite maintains its desired orbit
consistently?
a. Using small on-board rocket trusters
b. Through using guidance system
c. By telemetry channel
d. All of these
81. A satellite consists of any subsystem
functions incorporated into a single system.
What is the subsystem responsible for
providing the primary dc power and the
regulated, secondary supply voltages for the
satellite circuits?
a. Communication channel subsystem
b. Telemetry subsystem
c. Power subsystem

d. Antennas
82. How do communications satellites
powered?
a. By a bank of batteries whose charge is
maintained by an array of solar cells
b. Liquid fuel
c. Nuclear
d. AC power
83. _____________ is the total power
consumption for the satellite operation?
a. About 10W
b. About 150W
c. About 2000W
d. About 25000 W
84. As the height of a satellite orbits gets lower,
the speed of the satellite
a. Increases
b. Decreases
c. Remains the same
d. None of the above
85. The main function of a communications
satellite is the
a. Repeater
b. Reflector
c. Beacon
d. Observation platform
86. The key electronic component in a
communications satellite is the
a. Telemetry
b. On-board computer
c. Command and control system
d. Transponder
87. A circular orbit around the equator with a
24-h period is called a(n)
a. Elliptical orbit
b. Geostationary orbit
c. Polar orbit
d. Transfer obit
88. A satellite stays in orbit because the
following two factors are balanced.
a. Satellite weight and speed
b. Gravitational pull and inertia
c. Centripetal force and speed
d. Satellite weight and the pull of the moon
and sun
89. The height of a satellite in a synchronous
equatorial orbit is
a. 100 mi
b. 6800 mi
c. 22,300 mi
d. 35, 860 mi
90. Most satellites operate in which frequency

band?
a. 30 to 300 MHz
b. 300 MHz to 3 GHz
c. 3 GHz to 30 GHz
d. Above 300 GHz
91. The main power sources for a satellite are
a. Batteries
b. Solar cells
c. Fuel cells
d. Thermoelectric generators
92. The maximum height of an elliptical orbit is
called the
a. Perigee
b. Apex
c. Zenith
d. Apogee
93. Batteries are used to power all satellite
subsystems
a. At all times
b. Only during emergencies
c. During eclipse periods
d. To give the solar arrays a rest
94. The satellite subsystems that monitors and
controls the satellite is the
a. Propulsion subsystem
b. Power subsystem
c. Communications subsystem
d. Telemetry, tracking, and command
subsystem
95. The basic technique used to stabilized a
satellite is
a. Gravity-forward motion balance
b. Spin
c. Thrusters control
d. Solar panel orientation
96. The jet thrusters are usually fired to
a. Maintain altitude
b. Put the satellite into the transfer orbit
c. Inject the satellite into the
geosynchronous orbit
d. Bring the satellite back to the earth
97. Most commercial satellite activity occurs in
which band(s)?
a. L
b. C and Ku
c. X
d. S and P
98. How can multiple earth stations share a
satellite on the same frequencies?
a. Frequency reuse
b. Multiplexing
c. Mixing

d. They can’t
99. The typical bandwidth of a satellite band is
a. 36 MHz
b. 40 MHz
c. 70 MHz
d. 500 MHz
100. Which of the following is not usually a part
of a transponder?
a. LNA
b. Mixer
c. Modulator
d. HPA
COMMUNICATIONS ENGINEERING
PART 9
TELEPHONY
1. In International Telephone Numbering, a
digit or combination of digits characterizing
the called numbering area within a country
is called ________ code.
a. Local
b. CCITT
c. Baudot
d. Area
2. The last two digits of the loaded cable
designation 22E66 indicates
a. Spacing
b. Coil inductance
c. Wire gauge
d. Attenuation
3. A condition of a telephone handset, in which
it can be called, is _______ condition.
a. On-hook
b. Off-hook
c. Busy
d. None of these
4. When digits 3 is dialled using touch tone
system, the amount of time needed to send
the tone is
a. 0.1 sec
b. 50 msec
c. 0.25 sec
d. 0.25 sec
5. A telephone number perform the following
operations except
a. To route the call
b. To activate the necessary apparatus for
proper call charging
c. To order clearing of connection
d. None of the above
6. The number to be dialled or called to reach a

subscriber in the same local network or
numbering area is
a. Local code
b. Area code
c. Toll access code
d. Subscriber No.
7. That part of the telephone network between
the telephone instrument at the subscriber
premises and the central office equipment is
called the _______________.
a. Inter-office trunk
b. Tie line
c. Subscriber loop
d. Service drop wire
8. A line linking telephone central offices is
called _____________ line.
a. Tie
b. Inter-office trunk
c. Routing
d. Connector
9. A signalling technique wherein a number of
voice paths is carried over one common
channel instead of having individual voice
channels.
a. In band signalling
b. Out of band signalling
c. Common channel signalling
d. Alternate channel signalling
10. ___________ is a unit of telephone traffic
defined as one user making a call of ine
second duration.
a. CCS
b. Call-second
c. Erlangs
d. Call-hour
11. During a busy hour in a telephone system an
average of one call is lost, then the grade of
service is considered to be:
a. 1.01
b. 10%
c. 0.10%
d. 0.01
12. If a busy counts are made during the span of
15 minutes, and the average number of
occupied circuit is found to be 8, then the
traffic, in Erlang, is:
a. 2
b. 8
c. 6
d. 4
13. In a standard CCITT group, 12 channels
FDM, the carrier frequency of the channel

No. 1 is _______________.
a. 100 kHz
b. 102 kHz
c. 108 kHz
d. 60 kHz
14. In the FDM hierarchy, a mastergroup is
composed of ten supergroups and is
equivalent to
a. 600 channels
b. 60 channels
c. 180 channels
d. 120 channels
15. The approximation process in PCM creates
noise called:
a. Thermal
b. White noise
c. Quantizing noise
d. Agitation noise
16. The criteria to be considered in designing a
telephone system
a. Attenuation limit
b. Resistance limit
c. A or B
d. A and B
17. This refers to loop AC reference frequency
measured in decibels
a. Signalling limits
b. Resistance limits
c. Attenuation limits
d. All of these
18. An inuction coil which is multiple winding
transformer intended to interface a 2-wire
circuit to be a 4-wire circuit to permit twoway transmission of signals.
a. Hybrid function
b. Speech transformer
c. Transmission regulation circuit
d. A or B
19. A subscriber loop signalling method in
which signalling information is indicated by
the presence and absence of a battery and
ground condition on the line at the called
end of the trunk.
a. Wet- Dry
b. Reverse Battery
c. High- Low
d. Supervisory
20. An arrangement where the only possible
connection between a number of exchanges
is through a single tandem or transit
exchange where they are all connected.
a. Mesh

b. Star
c. Composite
d. Ring
21. CCITT recommendation E-161 recommends
that not more than ________ digits make up
an international number, excluding the
international prefix.
a. 10
b. 12
c. 16
d. 20
22. The following are the transmission media
used for telephone systems except:
a. Parallel wire
b. Coaxial wire
c. Fiber optics
d. NOTA
23. The subscriber loop provides the following
except:
a. Talk battery
b. Ringing voltage
c. Telephone dial
d. Current during on hook
24. A method of multiplexing in which the total
frequency spectrum available is used by
each channel, but not part of the time.
a. FDM
b. TDM
c. SDM
d. GSM
25. The primary cause of echo and singing is
a. Intermodulation noise
b. Crosstalk
c. Impedance mismatch
d. Thermal noise
26. For crosstalk to be considered intelligible, at
least ________ words are intelligible to the
listener in a seven second period.
a. 5
b. 6
c. 4
d. 3
27. Noise that is non-continuous, consisting of
irregular pulse or noise spikes of short
duration and of relatively high amplitude.
a. Solar
b. Intermodulation
c. Impulse
d. Crosstalk
28. The signal to noise ratio for voice based on
customer satisfaction is
a. 30 db

b. 35 db
c. 15 db
d. 20 db
29. dBa is a noise unit which uses a tone of
1000 Hz and a power level of
a. -85 dBm
b. -90dBm
c. 85dBm
d. -80dBm
30. The average intensity in one or more traffic
paths occupied in the busy hour by one 2minute call for an aggregate duration of two
minutes.
a. CCS
b. Cm
c. Erlang
d. EBHC
31. A method of handling lost calls wherein a
call failing to immediately find a server,
waits enters a queue until one becomes
available.
a. Lost Calls Cleared
b. Lost Calls Held
c. Lost Calls Delayed
d. NOTA
32. The main terminal used as cross connection
point for cables 300 pairs and above.
a. MTTC
b. MDF
c. DP
d. TTC
33. For PCM, the sampling theorem states that
the sampling frequency must be _________
the highest frequency contained in the
analog signal.
a. twice
b. more than twice
c. less than twice
d. equal to
34. a group of sixty voice channels with
bandwidth of 240 kHz is called a
a. group
b. supergroup
c. mastergroup
d. jumbogroup
35. On the subscriber’s telephone set employing
the touch tone technique, how many signals
are transmitted to the telephone exchange
for every button that is pressed?
a. 2 VHF signals
b. 1 VHF and 1 AF
c. 2 AF tones

d. 16 AF tones
36. An electronic circuit which is inserted into
the 4-wire trunk path effectively to block the
passage of reflected signal energy
a. Echo suppressor
b. Loading coil
c. Loop extender
d. Telephone amplifier
37. The following are signalling functions
except:
a. Ringing signals
b. Address signals
c. Supervisory signals
d. NOTA
38. The standard spacing for 19-D-88 cable
loading code is
a. 700 ft.
b. 6000 ft
c. 4500 ft
d. 3000 ft.
39. A telephone exchange has a subscriber loop
limit of 1800 ohms, excluding the telephone
instrument. What is the farthest distance, in
miles, that a subscriber can be located away
from the telephone exchange, if AWG 26
cable, which has a resistance of 431
ohms/loop mile, is used?
a. 5.95
b. 8.18
c. 3.9
d. 4.18
40. The Strowger or step-by-step system falls
under what type of switching control
system?
a. Manual
b. Progressive
c. Common
d. Automatic
41. For building telephone facilities, the size of
entrance conduit shall not be less than
_______ in diameter.
a. 30 mm
b. 50 mm
c. 60 mm
d. 75 mm
42. In telephony, tone dialing takes ________
time than pulse dialing.
a. Less
b. More
c. About the same
d. Can’t be determined
43. A telephone service wherein calls are

rerouted into a preassigned station is called
_________.
a. Camp-On
b. Call Forwading
c. Call Barring
d. Abbreviated Dialing
44. What type of control system crossbar
switches are operating?
a. Manual
b. Progressive
c. Common
d. Automatic
45. PABX stands for
a. Private All-purpose Broadcasting
Exchange
b. Private Automatic Branch Exchange
c. Public Access Bidirectional Exchange
d. Public Address Broadcasting Exchange
46. A trunk is
a. The base of a communication tower
b. A telephone line connecting two C.O.’s
c. A line connecting one telephone set to
the PABX
d. The structure where antenna are attached
47. The voice frequency channel pass band is:
a. 0 to 4000 Hz
b. 300 to 3000 Hz
c. To carry only speech
d. All of the preceding
48. What is used to transmit more than one
conversation over a path?
a. Hybrid
b. Tandem
c. Multiplexing
d. All of the above
49. The common channel interoffice signalling
method
a. Uses the same channel for signalling as
for the related conversation
b. Is used on local loops
c. Uses a separate channel for signalling
only
d. Comes the signalling for one related
conversation
50. Telephone switching is accomplished by
a. Manual Switchboard
b. Step-by-step Switches
c. Crossbar switches
d. Any of the preceding
51. The step-by-step switch
a. Was invented by Strowger
b. Generates much noise

c. Operates using a system of
electromechanical switches
d. All of these
52. The telephone was invented by
a. James Watson
b. Alexander Graham Bell
c. Phillip Reis
d. Almon Strowger
53. A switching network capable of providing a
path from every inlet link to every outlet
link in the absence of traffic.
a. Concentration
b. Blocking
c. Full availability switch
d. Crosspoint
54. An exchange primarily used as a switching
point for traffic between other exchanger is
a. Transfer system
b. Transit Exchange
c. Connecting point
d. Tandem Exchange
55. A telephone switch is an example of
________ switching
a. Packet
b. Message
c. Circuit
d. Virtual circuit
56. The local loop of a telephone system is
a. A two –wire communication circuit
between a customer’s premise and the
central office
b. A group of wires connecting a telephone
set to a modem
c. A four wire circuit connecting a fax
machine to a computer
d. A single piece of wire connecting the
subscriber’s telephone to another
telephone set.
57. Identical telephone numbers in different
parts of the country are distinguished by
their
a. Access codes
b. Country codes
c. Trunk prefixes
d. Area codes
58. A telephone switching system with a
capacity of 100 lines could assign telephone
numbers from
a. 0001 – 1000
b. 000- 999
c. 0000 – 1000
d. 001 – 999

59. The following are the building blocks of a
Step-by-step Switching System except:
a. Marker
b. Linefinder
c. Selector
d. Connector
60. Which has longer subscriber loop length, the
Central Office Switching equipment having
a resistance limit of
a. 5000 ohms
b. 1000 ohms
c. 1500 ohms
d. 2000 ohms
61. A fax transmission is usually at a _________
mode.
a. Simplex
b. Half duplex
c. Full duplex
d. Multiplex
62. A permanent circuit for private use within a
communications network
a. Two-wire
b. 4-wire
c. Switched
d. Leased
63. The class of exchange with the primary
function of connecting central offices when
a direct trunk is not available
a. Local
b. Gateway
c. Toll
d. Tandem
64. Dial tone, busy tone and ring back tones are
example of __________ signals.
a. Supervisory
b. Address
c. Musical
d. Digital
65. How much time in seconds is saved if we
use Touch Tone Dialing instead of Pulse
Dialing to call telephone number 781-1005?
a. 3.55
b. 7.75
c. 7.55
d. 7.15
66. With attenuation limit at 6 dB, what is the
length of cable using gauge 26 with
attenuation of 1.61 dB per km.
a. 1.3 km
b. 4.7 km
c. 3.7 km

d. 2.5 km
67. The maximum length for 1300-ohm
signalling or loop resistance using AWG No.
26 wire with 133.9 ohm per km.
a. 5.2 km
b. 4.7 km
c. 7.5 km
d. 9.7 km
68. The minimum size for an entrance conduit
for building telephone facilities.
a. 50 mm
b. 50 cm
c. 65 mm
d. 65 cm
69. The size of entrance conduit for a 100 pair
entrance cable.
a. 50 mm
b. 65 mm
c. 75 mm
d. 100 mm
70. The backboard color for the house or riser
cable
a. Yellow
b. White
c. Blue
d. Red
71. The maximum span from telephone pole to
the building for an aerial entrance cable.
a. 30 m
b. 600 mm
c. 45 m
d. 5.5 m
72. The sampling period for telephone signals
a. 8000 Hz
b. 125 usec
c. 6400 Hz
d. 100 usec
73. The inability to interconnect two idle lines
connected to a switching network due to all
possible paths are in use
a. Concentration
b. Blocking
c. Full availability
d. Crosspoint
74. The minimum depth for an underground
entrance conduit under areas used for
vehicular traffic inside private property
a. 300 mm
b. 600 mm
c. 50 mm
d. 1 m
75. The minimum clearance for aerial entrance

cables over areas accessible to pedestrians is
a. 4.5 m
b. 5.5 m
c. 3.5 m
d. 6.5 m
76. The steel gauge of the outdoor MTTC
a. 16
b. 18
c. 20
d. 22
77. PAM is:
a. A pulse system immune from noise
b. A digital system
c. A popular system for telephone
transmissions
d. An analog system
78. A suitable sampling rate for a signal
containing frequency components between
40 Hz and 4 kHz would be:
a. 10 kHz
b. 80 Hz
c. 90 Hz
d. 4.04 kHz
79. Quantization noise can be reduced by:
a. Taking samples at a faster rate
b. Using a PCM system
c. Increasing the number of standard
amplitude
d. Using higher amplitude signals
80. The name of the device invented by Johann
Philipp Reis in 1860 which could transmit a
musical tone over a wire to a distance point.
a. Harmonic telegraph
b. Phonograph
c. Telephone
d. Radio
81. When was the first complete sentence ever
transmitted by the telephone?
a. 1860
b. 1876
c. 1892
d. 1905
82. Who invented the first practical system for
the electrical switching of calls installed in
1892?
a. Bell
b. Watson
c. Edison
d. Strowger
83. What part of the conventional telephone set
transmitter and receiver unit are located?
a. Dial

b. Base
c. Keypad
d. Handset
84. The type of transmitter widely used in the
conventional telephone set.
a. Carbon
b. Ceramic
c. Piezoelectric
d. Electromagnetic
85. Who invented the first carbon type
transmitter?
a. Bell
b. Watson
c. Gray
d. Edison
86. The type of receiver widely used in the
conventional telephone set
a. Electromagnetic
b. Ceramic
c. Carbon
d. Piezoelectric
87. How many unique tones are used for the 12key dual-tone multifrequency keypad?
a. 2
b. 4
c. 7
d. 12
88. In the telephone industry, BORSCHT
functions are performed by
a. Subscriber line interface
b. Cross point matrix
c. Switching network
d. Connector switch
89. In the telephone unit, what is produced when
the balancing network in a hybrid circuit is
intentionally unbalanced slightly so that
small amount of transmitted signal is fed to
the receiver of the talking phone?
a. Dial tone
b. Side tone
c. Echo
d. Singing
90. The type of dialing possible for telephone
set with rotary dial.
a. Tone dialing
b. Pulse dialing
c. Loop dialing
d. E & m dialing
91. What is the standard bandwidth of voice
channel according to CCITT
recommendations?
a. 300 – 3.4 kHz

b. 200 – 3.3 kHz
c. 20 – 20 kHz
d. 30 – 30 k Hz
92. The signal heard on the telephone line that
indicates readiness of the central office in
receiving address or telephone number.
a. Dial tone
b. Ringing tone
c. Busy tone
d. Congestion tone
93. The signal heard on the telephone line which
indicates that the called subscriber set is in
use.
a. Dial tone
b. Ringing tone
c. Busy tone
d. Congestion tone
94. BORSCHT stands for
a. Battery, over-voltage protection,
ringing, supervision, coding, hybrid
and testing
b. Battery, over-hook regulator, ringing,
surge protect, circuit, hybrid and test
c. Name of the leading manufacturer of
telephone system
d. Acronym for the developers of computer
95. Request for service from the telephone is
detected at the Central Office as
a. Dial pulses
b. Ringing signal
c. Flow of loop current
d. Battery reversal
96. The location where all subscriber lines are
terminated and switching equipment facility
is installed.
a. Central office
b. Toll office
c. Gate way
d. Tandem
97. A private line communications channel of
the type provided by communication
common carrier for linking two or more
points together.
a. Party line
b. Tie line
c. DID line
d. Trunk line
98. The attenuation loss limit of the subscriber
loop is set at 6 dB. What is the maximum
length if a 26H88 loading coil with an
attenuation of 0.80 dB per kilometre is
added?

a. 1.5 km
b. 3.5 km
c. 5.5 km
d. 7.5 km
99. The first number of the loaded cable
designation 19H44 indicates
a. Spacing
b. Coil inductance
c. Wire gauge
d. Attenuation
100. The letter of the loaded cable designation
24B88 indicates
a. Spacing
b. Coil inductance
c. Wire gauge
d. Attenuation

MULTIPLE CHOICE
QUESTIONS
IN
ELECTRONICS SYSTEMS AND
TECHNOLOGIES (EST)

Digital and Data Communications
MELVIN C. ARCEO, ECE
PERC DC

ENCODED BY:
BADILLO, AIMIE E.
2006105942
ECE003/C11

1. It is defined as knowledge or intelligence that is
communicated between two or more points.
a. Carrier
b. Sideband
c. Information
d. Broadband
2.
3. What is the category of data transmission if
the binary pulse is maintained for the entire
bit time?
a. Return to zero
b. Bipolar
c. Unipolar
d. Non – return to zero
4.
5. Which medium is the most widely used in
LANs?
a. Twin Lead
b. Fiber – optic cable
c. Twisted Pair
d. Coax
6.
7. These are used for transmission of PCM
encoded time – division multiplexed digital
signal.
a. I carriers
b. E carriers
c. A carriers
d. T carriers
8.
9. Which of the following is not a typical FDM
application?
a. Telemetry
b. Stereo broadcasting
c. Telephone
d. Secure communications
10.
11. A LAN device that is used to interconnect
two networks that use different protocols
and formats.
a. Gateways
b. Routers
c. Bridges
d. Hubs
12.
13. A pulse modulation technique as the width
of a constant amplitude pulse is varied
proportional to the amplitude of the analog
signal at the time the signal is sampled.
a. Pulse Width Modulation
b. Pulse Length Modulation
c. Pulse Duration Modulation

d. All of these
14.
15. The FDM telephone systems accommodate
many channels by
a. Increasing the multiplexer size
b. Using many final carriers
c. Narrowing the bandwidth of each
d. Using
multiple
levels
of
multiplexing
16.
17. It is the transmittal of digitally modulated
analog signals (carrier) between two or more
points in a communications system.
a. Digital modulation
b. Digital transmission
c. Data communications
d. Pulse modulation
18.
19. Indicate which of the following systems is
digital.
a. Pulse-position modulation
b. Pulse-code modulation
c. Pulse–width modulation
d. Pulse-frequency modulation
20.
21. Classification of protocol that interprets a
frame of data as a group of successive bit
combined into predetermined pattern of
fixed length, usually 8 bits each.
a. Character-oriented protocols
b. Byte-oriented protocols
c. Bit-oriented protocols
d. Character and Byte-oriented
protocols
22.
23. Dividing the data block by a constant
produces a remainder that is used for error
detection. It is called the
a. Vertical redundancy check
b. Horizontal redundancy check
c. Block check character
d. Cyclic redundancy check
24.
25. Which of the following is not a benefit of
spread spectrum?
a. Jam – proof
b. Security
c. Immunity of fading
d. Noise proof
26.
27.
28. Converting analog signals to digital is done

by sampling and ___________.
a. Quantizing
b. Companding
c. Pre – emphasis
d. Mixing
29.
30. It is a process of converting an infinite
number of possibilities to a finite number of
conditions.
a. Sampling
b. Coding
c. Quantization
d. Aliasing
31.
32. In T1, it is equal to the reciprocal of the
sample rate
a. Slot Time
b. Transmission time
c. Frame time
d. Bit rate
33.
34. What is the final output of a multiplexer?
a. Baseband
b. Composite baseband
c. Information
d. Composite carrier
35.
36. The baud rate
a. is always equal to the bit transfer rate
b. is equal to twice the bandwidth of
an ideal channel
c. is not equal to the signaling rate
d. is equal to one – half the bandwidth
of an ideal channel
37.
38. Bit errors in data transmission are usually
caused by
a. equipment failures
b. typing mistakes
c. noise
d. poor S/N ratio at receiver
39.
40. A digital modulation technique which is a
form of constant – amplitude angle
modulation similar to standard frequency
modulation except the modulating signal is
binary signal that varies between two
discreet voltage levels.
a. QAM
b. ASK
c. PSK
d. FSK

41.
42. Start and stop bits, respectively, are
a. Mark, space
b. Space, mark
c. Space, space
d. Mark, mark
43.
44. It is the processing of analog signals using
digital methods and includes band limiting
and signals with filters, amplitude
equalization, and phase shifting
a. Digital communications
b. Digital Signal Processing
c. Data communications
d. Carrier recovery method
45.
46. It is a network access method used primarily
with LANs configured in a ring topology
using either baseband or broadband
transmission formats
a. Ethernet
b. Token passing
c. Token ring
d. Token bus
47.
48. A small telephone switching system that can
be used as a LAN is called
a. Ring
b. WAN
c. UART
d. PBX
49.
50. The most common method used for
sampling voice signals in PCM systems
a. unnatural sampling
b. flat top sampling
c. natural sampling
d. free sampling
51.
52. In PCM, it converts the PAM sampled to
parallel PCM codes
a. Analog-to-Digital converter
b. Digital-to-analog converter
c. Pre-emphasis circuit
d. Compander
53.
54. The OSI layer that provides the control
functions necessary to establish, manage and
terminated the connections as required to
satisfy the user request.
a. Application layer
b. Network layer

c. Session layer
d. Physical layer
55.
56. In PAM demultiplexing, the receiver clock is
derived from
a. standard radio station WWV
b. a highly accurate internal oscillator
c. the PAM signal itself
d. the 60 Hertz power line
57.
58. It is also known as digital modulation
a. Digital transmission
b. Digital sampling
c. Digital radio
d. Data transmission
59.
60. Time – division multiplex
a. can be used with PCM only
b. combines five groups into
supergroup
c. stacks 24 channels in adjacent
frequency slots
d. interleaves pulses belonging to
different transmissions
61.
62. It is a numerical indication of how
efficiently a PCM code is utilized
a. Coding efficiency
b. Companding
c. Pre-emphasis
d. Dynamic Range
63.
64. Type of PCM which is designed to take
advantage
of
the
sample-to-sample
redundancies in the typical speech
waveform
a. Single – bit PCM code
b. Pulse Code Modulation
c. Differential PCM
d. Delta modulation
65.
66. The Basic Rate Interface (BRI) of ISDN has
a total bit rate of _____.
a. 192 kbps
b. 148 kbps
c. 64 kbps
d. 1.544 Mbps
67.
68. A form of angle – modulated, constant
amplitude digital modulation similar to
conventional phase modulation except its
input is binary digital signal and there are

limited numbers of output phase possible.
a. ASK
b. PSK
c. FSK
d. QAM
69.
70. The main circuit in a PSN generator is ____.
a. XOR
b. Multiplexer
c. Shift register
d. Mixer
71.
72. The circuit that performs demultiplexing in
an FDM system is _____.
a. Op - Amp
b. Bandpass filter
c. Discriminator
d. Subcarrier oscillator
73.
74. __________ defines how a user gets control
of the channel so as to allow transmission.
a. channel access
b. collision detection
c. collision avoidance
d. carrier sense
75.
76. The fastest LAN topology is the
a. ring
b. bus
c. star
d. square
77.
78. It is a the symmetrical expectation of the bit
error rate in the system
a. probability of errors
b. error detection
c. error control
d. bit error rate
79.
80. It is simply the data rate at which serial
PCM bits are clocked out of the PCM
encoder onto the transmission line.
a. line speed
b. baud rate
c. output rate
d. bit rate
81.
82. A quantizing is _______.
a. Multiplexer
b. Demultiplexer
c. A/D converter
d. D/A converter

83.
84. Refers to the rate of change of a signal on a
transmission medium after encoding and
modulation have occurred
a. baud rate
b. phase shift
c. bit rate
d. frequency deviation
85.
86. The magnitude difference between adjacent
steps in quantization is called __________.
a. Quantum
b. Step size
c. Resolution
d. Any of these
87.
88. It is a set of rules implementing and
governing an orderly exchange of data
between layers of two devices, such as line
control units and front – end processors.
a. Data Link Protocol
b. Network Protocol
c. Point to Point Protocol
d. File Transfer Protocol
89.
90. A signaling system in which each letter of
the alphabet is represented by a different
symbol is not used because
a. it would be too difficult for an
operator to memorize
b. it is redundant
c. noise would introduce too many
errors
d. too many pulses per letter are
required
91.
92. A modulation process that involves
conversion of a waveform from analog to
digital form by means of coding.
a. PDM
b. PCM
c. PLM
d. PAM
93.
94. What is the bandwidth required to transmit
at a rate of 10 Mbps in the presence of a 28bd S/N ratio?
a. 1.075 MHz
b. 10 Mhz
c. 5 Mhz
d. 10.5 Mhz
95. The slope of the analog signal is greater than

the delta modulator can maintain
a. overload distortion
b. granular noise
c. slope overload
d. peak limiting
96.
97. A scheme in which several channels are
interleaved and then transmitted together is
known as
a. Frequency division multiplex
b. Time division multiplex
c. a group
d. a supergroup
98.
99. The best frequency demodulator is the
a. PLL discriminator
b. Pulse-averaging discriminator
c. Foster-Seeley discriminator
d. Radio detector
100.
101.
What property distinguishes digital
radio systems from conventional analog
communications system?
a. the type of carrier used in the
transmission of data
b. the nature of the modulating signal
c. the type of modulation of data to be
used
d. the nature of the transmitter and
receiver to be used
102.
103.
The circuit switch is a _______
switch.
a. See – through
b. Transparent
c. Vague
d. Opaque
104.
105.
A carrier recovery is needed with
a. FSK
b. BPSK
c. DPSK
d. QAM
106.
107.
The Hartley – Shannon theorem sets
a limit on the
a. highest frequency that may be sent
over a given channel
b. maximum capacity of a channel
with a given noise level
c. maximum number of coding levels
in a channel with a given noise level

d. maximum number of quantizing
levels in a channel of a given
bandwidth
108.
109.
The phase relationship between
signaling elements for BPSK is the optimum
signaling format and occurs only when two
binary signal levels are allowed and when
one signal is the exact negative of the other.
a. Antipodal signaling
b. Carrier recovery
c. Squaring loop
d. Phase referencing
110.
111.
Pulse – amplitude modulation signals
are multiplexed by using
a. Subcarrier
b. Bandpass filters
c. A/D converters
d. FET switches
112.
113.
It is the ratio of the transmission bit
rate to the minimum bandwidth required for
a particular modulation scheme.
a. Bandwidth efficiency
b. All of these
c. Information density
d. Spectral efficiency
114.
115.
Ethernet is baseband transmission
system designed by _____.
a. Thomas Murray and Robert Metcalfe
b. David Boggs and Thomas Murray
c. Thomas Murray and Emile Baudot
d. Robert Metcalfe and David Boggs
116.
117.
It is a system where the digital
signals are placed directly on the coaxial
cable.
a. Broadband
b. Baseband
c. CSMA/CD
d. Token ring
118.
119.
A basic group B
a. Occupies the frequency range
from 60 to 108 kHz
b. Consists of erect channels only
c. Is formed at the group translating
equipment
d. Consists of 5 supergroups
120.

121.
122.
Which of the following is not
primarily type of data communications?
a. a telephone
b. teletype
c. telegraph
d. CW
123.
124.
Packets which is self – contained and
travels through the network independent of
other packets of the same message by
whatever means available.
a. Packet
b. Frame
c. Datagram
d. Data
125.
126.
Transmitting the data signal directly
over the medium is referred to as
a. baseband
b. broadband
c. ring
d. bus
127.
128.
The main reason that serial
transmission is preferred to parallel
transmission is that?
a. serial is faster
b. serial requires only a single channel
c. serial requires multiple channels
d. parallel is too expensive
129.
130.
Which of the following is not a
LAN?
a. PBX system
b. Hospital system
c. Office building system
d. Cable TV system
131.
132.
A modulation technique where data
rates in excess of 56 kbps can be achieved
over telephone circuits
a. ASK
b. Trellis Code Modulation
c. GSK
d. Any of these
133.
134.
It is how the primary designates the
secondary as the designation of recipient of
data.
a. Line turnaround
b. Selection

c. Line control
d. Control Protocol
135.
136.
It is the process of compressing and
expanding and is a means of improving the
dynamic range of communications system.
a. Pre-emphasis
b. Filtering
c. De-emphasis
d. Companding
137.
138.
The supergroup pilot is
a. applied to each multiplexing bay
b. used to regulate the gain of
individual repeaters
c. applied at each adjustable equalizer
d. fed in at a GTE
139.
140.
The time it takes to transmit one
TDM frame is called _________.
a. Slot time
b. Frame time
c. Transmission time
d. Any of these
141.
142.
It is the thermal noise power
normalized to 1-Hz bandwidth
a. power density ratio
b. thermal noise
c. noise power density
d. ambient temperature noise
143.
144.
It is the procedure used to decide
which device has the permission to transmit
at any given time
a. Flow control
b. Sequence control
c. Line control
d. Framing
145.
146.
Any rounded – off errors in the
transmitted signal are reproduced when the
code is converted back to analog in the
receiver.
a. Aperture error
b. Quantization error
c. Aperture distortion
d. Slope overload
147.
148.
The biggest disadvantage of PCM is
a. its inability to handle analog signals
b. the high error rate which is

c.
d.
149.
a.
b.
c.
d.

quantizing noise introduces
its incompatibility with TDM
the large bandwidths that are
required for it
T1 stands for
Transmission one
Telecommunication one
Telex one
Transmission line one

150.
151.
Involves
compression in the
transmitter after the input sample has been
converted to a linear PCM code and then
expansion in the receiver prior to PCM
coding
a. analog companding
b. A – law companding
c. Digital companding
d. U – law companding
152.
153.
Mark and space refer respectively to
a. dot and dash
b. message and interval
c. binary 1 and binary 0
d. on and off
154.
155.
Variation of biphase that is used for
encoding SMPTE time code data and for
recording on video tapes
a. Biphase - M
b. B8Z
c. Manchester
d. UPNRZ
156.
157.
Pulse width modulation may be
generated
a. by differentiating pulse position
modulation
b. with a monostable multivibrator
c. by integrating the signal
d. with a free running multivibrator
158.
159.
The ISDN channel D designates
_____ which contains control information.
a. Data
b. Flow
c. Control
d. Bearer
160.
161.
A transmission of binary data which
involves the transmission of two non – zero
voltage level

a.
b.
c.
d.
162.
163.
164.

Unipolar
Polar
Bipolar
Non – return to zero

Switching systems
a. improve the efficiency of data
transfer
b. are not used in data systems
c. require additional lines
d. are limited to small data networks

165.
166.
It involves converting standard logic
levels to a form more suitable to telephone
transmission lines
a. Transmission line encoding
b. Physical line encoding
c. Digital line encoding
d. Multiplexing
167.
168.
The primary advantage of digital
transmission
a. economical
b. reliability
c. noise immunity
d. efficiency
169.
170.
Part of the PCM system that prevents
aliasing or foldover distortion
a. Bandpass filter
b. Anti – foldover distortion
c. Anti – aliasing
d. Any of these
171.
172.
It is defined as the process of
transforming messages or signals in
accordance with a definite set of rules.
a. Quantizing
b. Sampling
c. Coding
d. Decoding
173.
174.
The PCM code for each channel
occupies a fixed time slot called
a. Frame time
b. Baud
c. Transmission time
d. Epoch
175.
176.
The building block of a parity or
BCC generator is _________.

a.
b.
c.
d.

Shift register
XOR
2 – to – 4 level converter
UART

177.
178.
179.
An IC that contains A/D and D/A
converters, companders, and parallel-toserial converters is called a
a. Codec
b. Data converter
c. Multiplexer
d. Modem
180.
181.
Data communications refers to the
transmission of
a. voice
b. video
c. computer data
d. all of the above
182.
183.
The number of amplitude, frequency,
or phase changes that take place per second
is known as the
a. data rate in bits per second
b. frequency of operation
c. speed limit
d. baud rate
184.
185.
The
basic
modulator
and
demodulator circuits in PSK are
a. PLLs
b. Balanced modulators
c. Shift registers
d. Linear summers
186.
187.
What is the result if the input of
ADC is changing while performing
conversion?
a. Aperture error
b. Overload distortion
c. Aliasing
d. Aperture distortion
188.
189.
Information capacity is convenient to
express as
a. baud
b. bits
c. dot length
d. bits per second or bps
190.
191.
Which medium is the least

susceptible to noise?
a. twin lead
b. fiber – optic cable
c. twisted pair
d. coax
192.
193.
194.
The RS – 232 interface
a. interconnects data sets and the
transmission circuits
b. uses several different connectors
c. permits custom wiring of signal lines
to the connector pins as desired
d. all of the above
195.
196.
The ISDN channel B designates
_________.
a. Bearer
b. Data
c. Control
d. Flow
197.
198.
Data transmission of the character at
a time with start and stop bits is known as
what type of transmission?
a. asynchronous
b. serial
c. synchronous
d. parallel
199.
200.
Sampling technique that when the
tops of the sample pulses retain their natural
shape during the sample interval
a. unnatural sampling
b. flat top sampling
c. natural sampling
d. free sampling
201.
202.
A modem converts
a. Analog signals to digital
b. Digital signals to analog
c. Digital signals to analog and viceversa
d. None of these
203.
204.
205.
It is a large scale integration chip
designed for use in telecommunication
industry for private branch exchanges,
central office switches, digital handsets
and digital echo suppressors.
a. Vocoder

b. Modem
c. Codec
d. Muldem
206.
207.
What is the type of mastergroup used
for low – capacity microwave systems?
a. A600
b. U600
c. L600
d. L400
208.
209.
An FDM hierarchy which is formed
by frequency – division multiplexing five
groups containing 12 channels each for a
combined bandwidth of 240 kHz.
a. Supergroup
b. Group
c. Mastergroup
d. Jumbogroup
210.
211.
The result whenever the sampling
rate is less than twice the highest audio
frequency
a. peak limiting
b. overload distortion
c. alias
d. quantizing noise
212.
213.
The most critical and difficult part
of receiving a direct – sequence spread
spectrum signal is
a. Frequency synthesis
b. Synchronism
c. PSN code generation
d. Carrier recovery
214.
215.
An FDM hierarchy which is formed
by frequency – division multiplexing 10
super groups together for a combined
capacity of 600 voice band message
channels
a. Supergroup
b. Group
c. Mastergroup
d. Jumbogroup
216.
217.
It is the transmittal of digital signals
between to or more points in a
communication system.
a. Digital transmittal
b. Digital communications
c. Digital radio

d. Data communications
218.
219.
It is logically equivalent to making
telephone call through the DDD network
except no direct end-to-end connection is
made
a. Normal call
b. Completed call
c. Logical call
d. Virtual call
220.
221.
It is proposed network designed by
major telephone companies in conjunction
with the ITU-T with the intent of
providing worldwide telecommunications
support for voice, data, video and
facsimile information within the same
network
a. ISDN
b. Broadband communications
c. ATM
d. Ethernet
222.
223.
Full duplex operation
a. requires two pair of cables
b. can transfer data in both directions at
once
c. requires modems at both ends of the
circuit
d. all of these
224.
225.
The most widely used data
communications code is
a. Morse code
b. ASCII
c. Baudot
d. EBCDIC
226.
227.
Ten bit error occurs in two million
transmitted. The bit error rate is
a. 2 x 10^-5
b. 5 x 10^-5
c. 5 x 10^-6
d. 2 x 10^-6
228.
229.
It is a type of FSK where the mark
and space frequencies are synchronized
with the input binary rate
a. QFSK
b. GFSK
c. CPFSK
d. GSK

230.
231.
A form of digital modulation similar
to PSK except the digital information is
contained in both the amplitude and the
phase of the transmitted carrier.
a. ASK
b. FSK
c. QAM
d. PSK
232.
233.
For the 16-PSK and a transmission
system with a 10kHz bandwidth,
determine the maximum bit rate
a. 40,000 bps
b. 80,000 bps
c. 20,000 bps
d. 16,000 bps
234.
235.
It is an empirical record of a
system’s actual bit error performance.
a. probability of error
b. error detection
c. error control
d. bit error rate
236.
237.
It is a function of the carrier-to-noise
power ratio and the number of possible
encoding conditions used
a. probability of error
b. error detection
c. error control
d. bit error rate
238.
239.
It is used to compare two or more
digital modulation systems that use
different transmission rates, modulation
scheme or encoding techniques
a. Energy per b it-to-noise power
density ratio
b. Noise power density
c. Power density ratio
d. Carrier-to-noise ratio
240.
241.
Indicate which of the following is
not a binary code
a. Morse
b. Baudot
c. CCITT-2
d. ARQ
242.
243.
To permit the selection of 1 out of 16
equiprobable events, the number of bits

required is
a. 2
b. log 16 base 10
c. 8
d. 4
244.
245.
The type of modulation most often
used with direct-sequence spread spectrum
is
a. QAM
b. SSB
c. FSK
d. PSK
246.
247.
Indicate the false statement. In order
to combat noise,
a. the channel bandwidth may be
increased
b. redundancy may be used
c. the transmitted power may be
increased
d. the signaling rate may be reduced
248.
249.
Which of the following is not
commonly used method of error detection?
a. Parity
b. BCC
c. CRC
d. redundancy
250.
251.
Quantizing noise occurs in
a. time-division multiplex
b. frequency-division multiplex
c. pulse-code modulation
d. pulse-width modulation
252.
253.
In order to reduce quantizing noise,
one must
a. increase the number of standard
amplitudes
b. send pulses whose sides are more
nearly vertical
c. use an RF amplifier at the receiver
d. increase the number of samples per
second
254.
255.
Companding is used
a. to overcome quantizing noise in
PCM
b. in PCM transmitters, to allow
amplitude limiting in the receiver
c. to protect small signals in PCM

form quantizing distortion
d. in PCM receivers, to overcome
impulse noise
256.
257.
Transmitting data as serial binary
word is called _______.
a. digital communications
b. quantizing
c. PAM
d. PCM
258.
259.
Emphasizing low-level signals and
compressing higher level signals is called
a. quantizing
b. companding
c. pre-emphasis
d. sampling
260.
261.
Which circuit is most common to
both frequency-hopping and directsequence spread spectrum transmitters?
a. correlator
b. frequency synthesizer
c. PSN code generator
d. Sweep generator
262.
263.
One of the most important aspect of
any communication system because it is
costly and limited
a. bandwidth
b. equipments
c. time
d. personnel
264.
265.
It consist essentially of sampling
analog information signals and then
converting those samples into discreet
pulses of transporting the pulses from the
source to destination over a physical
transmission medium
a. Pulse modulation
b. Amplitude modulation
c. Frequency modulation
d. Digital modulation
266.
267.
He is credited with inventing PCM in
1937
a. N. S. Kapany
b. A. H. Reeves
c. E. H. Alpine
d. A. C. S. Van Heel
268.

269.

Data communications uses
a. Analog methods
b. Digital methods
c. All of these
d. None of these
270.
271.
An integrated circuit that performs
the PCM encoding and decoding functions
a. Codec
b. Modem
c. Muldem
d. Digital-to-analog converter
272.
A synchronous transmission usually
begins with which character?
a. SYN
b. STX
c. SOH
d. ETB
273.
274.
A theory that establishes the
minimum sampling rate that can be used
for a given PCM systems
a. Nyquist sampling theorem
b. Nyquist minimum bandwidth
c. Nyquist minimum bandwidth
d. Any of these
275.
276.
Sixteen different levels (symbols) are
used to encode binary data. The channel
bandwidth is 36 MHz. The maximum
channel capacity is
a. 18 Mbps
b. 72 Mbps
c. 288 Mbps
d. 2.176 Gbps
277.
278.
Assigning PCM codes to absolute
magnitudes
a. Coding
b. Quantizing
c. Sampling
d. Any of these
279.
280.
A popular PC protocol is
a. Parity
b. Xmodem
c. CRC
d. LRC
281.
282.
It is the ratio of the largest possible
magnitude to the smallest possible
magnitude that can be decoded by the

digital-to-analog converter in the receiver
a. Coding efficiency
b. Companding
c. Pre-emphasis
d. Dynamic range
283.
284.
Devices used for digitizing speech
signals only
a. codec
b. muldem
c. vocoders
d. modem
285.
What is the minimum bandwidth
required to transmit a 56 kbps binary
signal with no noise?
a. 14 kHz
b. 56 kHz
c. 28 kHz
d. 112 kHz
286.
287.
Type of PCM that uses single-bit
PCM code to achieve digital transmission
of analog signals
a. Adaptive delta modulation
b. Pulse code modulation
c. Differential modulation
d. Delta modulation
288.
289.
It is a delta modulation system where
the step size of the digital-to-analog
converter
is
automatically
varied,
depending on the analog input signal.
a. Adaptive Delta Modulation
b. PCM
c. Differential modulation
d. Delta modulation
290.
291.
A QAM modulator does not use
____.
a. XNOR
b. Bit Splitter
c. Balanced modulator
d. 2-to-4 level converter
292.
293.
It is a form of phase-division
multiplexing where two data channels
modulate the same carrier frequency that
is shifted 90 degrees in phase.
a. PSK
b. FSK
c. QAM
d. ASK

294.
295.
One eight-bit PCM code is called
______.
a. FDM frame
b. TDM time slot
c. TDM frame
d. FDM time slot
296.
297.
It is communications system that
uses digital pulse rather than analog
signals to encode information
a. Digital carrier system
b. Digital baseband system
c. Digital service system
d. Digital broadband system
298.

299.
A special device that upgrades
signals from one level to a higher level of
the hierarchy in multiplexing
a. Muldem
b. Vocoder
c. Modem
d. Codec
300.
301.
A transmission of binary data which
involves the transmission of only a single
non-zero voltage level.
a. Unipolar
b. Bipolar
c. Polar
d. Non-return to zero
302.

303.

304.

MULTIPLE CHOICE

305.
QUESTIONS
306.

307. IN
308.

309. ELECTRONICS SYSTEMS AND
TECHNOLOGIES (EST)
310.

311.

Antennas
312.

313. MELVIN C. ARCEO, ECE
314. PERC DC
315.
316.

317. ENCODED BY:
318.
321.
322.
323.
324.
325.
326.
327.
328.

329.
330.
331.
332.
333.
334.
335.
336.

BADILLO, AIMIE E.
319. 2006105942
320. ECE003/C11

1. It is a metallic conductor system capable of
radiating and capturing electromagnetic
energy
a. transmission lines
b. antenna
c. waveguides
d. load
337.
2. A directional antenna with two or more
elements is known as
a. folded dipole
b. ground plane
c. loop
d. array
338.
3. The ratio of the focal length to the diameter
of the mouth of the parabola is called _____.
a. aperture
b. focal point
c. foci
d. major axis
339.
4. The impedance of a dipole is about
a. 50-ohm
b. 73-ohm
c. 93-ohm
d. 300-ohm
340.
5. A special type of transmission line that
consist of conducting metallic tube through
which high frequency electromagnetic
energy is propagated
a. medium
b. microstrip
c. stripline
d. waveguide
341.
6. Calculate the angle of declination for an
antenna using a polar mount at a latitude of
45 degrees
a. 3.2 degrees
b. 1.3 degrees
c. 4.2 degrees
d. 6.81 degrees
342.
7. The cone angle of the flare angle of a
conical horn antenna is approximately
a. 55 degrees
b. 45 degrees
c. 40 degrees
d. 50 degrees
343.

8. Electrical energy that has escaped into free
space in the form of transverse
electromagnetic waves
a. Radio waves
b. Frequency
c. Signal
d. Wavelength
344.
9. The length of the ground plane vertical at
146 MHz is
a. 1.6 ft
b. 1.68 ft
c. 2.05 ft
d. 3.37 ft
345.
10. Using a small reflector to beam waves to the
larger parabolic reflector is known as
a. Focal feed
b. Horn feed
c. Cassegrain feed
d. Coax feed
346.
11. The plane parallel to the mutually
perpendicular line in the electric and
magnetic fields is called _______.
a. wavefront
b. point source
c. isotropic source
d. rays
347.
12. What is the beamwidth of a parabolic
antenna with a diameter of 5 meters and an
operating frequency of 10 GHz?
a. 0.5 degrees
b. 0.675 degrees
c. 0.348 degrees
d. 3.48 degrees
348.
13. The horizontal radiation pattern of a dipole
is a
a. circle
b. figure of eight
c. clover leaf
d. narrow beam
349.
14. The size of antenna is inversely proportional
to _______.
a. frequency
b. power
c. radiation resistance
d. wavelength
350.

15. A popular half – wave antenna is the
a. Ground plane
b. End-fire
c. Collinear
d. Dipole
351.
16. Calculate the gain of a parabolic antenna
using a 2.5-m radius dish operating at
10GHz.
a. 166.673 dB
b. 83.7 dB
c. 52.2 dB
d. 45.6 dB
352.
17. It is the ratio of the radiated to the reflected
energy
a. Radiation resistance
b. Radiation efficiency
c. Radiation constant
d. Radiation antenna
353.
18. The feed mechanism in a parabolic antenna
that radiates the electromagnetic energy.
a. Primary antenna
b. Reflectors
c. Secondary antenna
d. Focal point
354.
19. It is a polar diagram or graph representing
field strengths or power densities at various
angular positions relative to an antenna
a. Side lobe
b. Front lobe
c. Radiation pattern
d. Radiation constant
355.
20. For a transmit antenna with a radiation
resistance of 72 ohms, an effective antenna
resistance of 8 ohms, a directive gain of 20
and an input power of 100W, determine the
antenna gain.
a. 12.55 dB
b. 10.43 dB
c. 11.21 dB
d. 9.78 dB
356.
21. The radiation pattern plotted in terms of
electric field strength or power density
a. absolute radiation pattern
b. relative radiation pattern
c. absolute front lobe pattern
d. absolute side lobe pattern

22. Calculate the characteristic impedance of a
quarter – wavelength section used to connect
a 300-ohm antenna to a 75-ohm line
a. 150 ohms
b. 120 ohms
c. 130 ohms
d. 110 ohms
357.
23. Plots of field strength or power density with
respect to the value at a reference point
a. absolute front lobe pattern
b. relative front lobe pattern
c. relative front lobe pattern
d. relative radiation pattern
358.
24. What must be the height of a vertical
radiator one half wavelength high if the
operating frequency is 1100 kHz?
a. 120 m
b. 136 m
c. 115 m
d. 124 m
359.
25. Lobes adjacent to the front lobe
a. Diagonal lobes
b. Side lobes
c. Front lobes
d. Back lobes
360.
26. Lobes in a direction exactly opposite of the
front lobe
a. Side lobes
b. Adjacent lobes
c. Front lobes
d. Back lobes
361.
27. Calculate the efficiency of an antenna that
has a radiation resistance of 73 ohms and an
effective dissipation resistance of 5 ohms
a. 98.3%
b. 93.6%
c. 90.7%
d. 95.5%
362.
28. The line bisecting the major lobe, or
pointing from the center of the antenna in
the direction of maximum radiation is called
_______.
a. line of shoot
b. diagonal shoot
c. bisecting shoot
d. antenna shoot

29. The ammeter connected at the base of a
Marconi antenna has a certain reading. If
this reading is increased 2.77 times, what is
the increase in output power?
a. 3.45
b. 1.89
c. 2.35
d. 7.67
363.
30. Refers to a field pattern that is close to the
antenna.
a. Induction field
b. Far field
c. Radiation field
d. Capture field
364.
31. A half-wave dipole is driven with a 5-W
signal at 225 MHz. A receiving dipole 100
km. Calculate the received power into a 73ohm receiver.
a. 23.5 pW
b. 7.57 pW
c. 5.64 pW
d. 1.26 pW
365.
32. It is the resistance that, if it replaced the
antenna, would dissipate exactly the same
amount of power that the antenna radiates.
a. Directive gain
b. Antenna efficiency
c. Radiation resistance
d. Antenna resistance
366.
33. What is the effective radiated power of a
television broadcast station if the output of
the transmitter is 1000W, antenna
transmission line loss is 50W, and the
antenna power gain is 3?
a. 1250 W
b. 2370 W
c. 2130 W
d. 2850 W
367.
34. It is the ratio of the power radiated by an
antenna to the sum of the power radiated and
the power dissipated.
a. radiation resistance
b. coupling coefficient
c. antenna efficiency
d. antenna beamwidth
368.
369.

35. It is the ratio of the power radiated by the
antenna to the total input power.
a. antenna efficiency
b. reflection coefficient
c. standing wave ratio
d. radiation resistance
370.
36. If a 500 kHz transmitter of a constant power
produces field strength of 100uV/m at a
distance of 100 mi from the transmitter,
what would be the theoretical field strength
at a distance of 200 mi from the transmitter?
a. 45 uV/m
b. 100 uV/m
c. 50 uV/m
d. 35 uV/m
371.
37. An antenna that transmits or receives
equally well in all directions is said to be
_____.
a. omnidirectional
b. bidirectional
c. unidirectional
d. quasidirectional
372.
38. It is the ratio of the power density radiated
in a particular direction to the power density
radiated to the same point by a reference
antenna, assuming both antennas are
radiating the same amount of power
a. power gain
b. directive gain
c. total gain
d. system gain
373.
39. If the field intensity of 25 mV/m develops
2.7 V in a certain antenna, what is its
effective height?
a. 110 m
b. 100 m
c. 98 m
d. 108 m
374.
40. The magnetic field of an antenna is
perpendicular to the earth. The antenna’s
polarization ______.
a. is vertical
b. is horizontal
c. is circular
d. cannot be determined from the
information given
375.

41. If the power of a 500 kHz transmitter is
increased from 150 W to 300 W, what would
be the percentage change in field intensity at
a given distance from the transmitter?
a. 141%
b. 150%
c. 100%
d. 133%
376.
42. It is the same with directive gain except that
the total power fed to the antenna is used
and the antenna efficiency is taken into
account.
a. system gain
b. power gain
c. directive gain
d. total gain
377.
43. A hip-radio telephone transmitter operates
on 2738 kHz. At a certain point distant from
the transmitter, the 2738 kHz signal is
measured field of 147 mV/m. The second
harmonic field at the same point is measured
as 405 uV/m. To the nearest whole unit in
decibels, how much has the harmonic
emission been attenuated below the 2738
kHz fundamental?
a. 43.2 dB
b. 51.2 dB
c. 35.1 dB
d. 25.1 dB
378.
44. It is the equivalent power that an isotropic
antenna would have to radiate to achieve the
same power density in the chosen direction
at a given point as another antenna.
a. EIRP
b. ERP
c. IRL
d. RSL
379.
45. When the energy is applied to the antenna at
a point of high – circulating current.
a. voltage-fed antenna
b. power-fed antenna
c. current-fed antenna
d. impedance-fed antenna
380.
46. For a transmit antenna with a power gain of
10 and an input power of 100W, determine
the EIRP in watts.
a. 30 dBW

b. 40 dBW
c. 50 dBW
d. 20 dBW
381.
47. If energy is applied at the geometrical center
of antenna, the antenna is said to be _____.
a. center-fed
b. end-fed
c. quarterwave-fed
d. halfwave-fed
382.
48. For a transmit antenna with a power gain of
10 and an input power of 100W, determine
the power density at a point 10 km from the
transmit antenna
a. 0.574 uW/m^2
b. 0.796 uW/m^2
c. 1.24 uW/m^2
d. 0.981 uW/m^2
383.
49. For a transmit antenna with a radiation
resistance of 72 ohms, an effective antenna
resistance of 8 ohms, a directive gain of 20
and an input power of 100W, determine the
antenna efficiency.
a. 90%
b. 96%
c. 98%
d. 96%
384.
50. The fields surrounding the antenna do not
collapse their energy back into the antenna
but rather radiate it out in space.
a. induction field
b. near field
c. radiation field
d. magnetic field
385.
51. For receive power density of 10 uW/m^2
and a receive antenna with a capture area of
0.2 m^2, determine the captured power.
a. 0.5 uW
b. 2 uW
c. 1 uW
d. 1.5 uW
386.
52. The property of interchangeability for the
transmitting and receiving operations is
known as ______.
a. efficiency
b. accuracy
c. reciprocity

d. polarization
387.
53. The length of a doublet at 27 MHz is _____.
a. 8.67 ft
b. 17.3 ft
c. 18.2 ft
d. 34.67 ft
388.
54. Refers to the orientation of the electric field
radiated from an antenna.
a. efficiency
b. beamwidth
c. polarization
d. accuracy
389.
55. At frequencies below 2 MHz, what type of
antenna is usually used?
a. Marconi antenna
b. Hertzian antenna
c. Hertz antenna
d. Elementary doublet
390.
56. The angular separation between two halfpower points in the major lobe of the
antenna’s plane radiation pattern.
a. bandwidth
b. polarization
c. efficiency
d. beamwidth
391.
57. Hertz antenna are predominantly used with
frequencies above
a. 3 MHz
b. 4 MHz
c. 5MHz
d. 2MHz
392.
58. Defined as the frequency range over which
antenna operation is satisfactory
a. beamwidth
b. channel
c. bandwidth
d. baseband
393.
59. One of the following is not an
omnidirectional antenna.
a. Half-wave dipole
b. Log-periodic
c. Discone
d. Marconi
394.
60. The point on the antenna where the

transmission line is connected is called
_______.
a. center feed
b. end feed
c. feedpoint
d. voltage feed
395.
61. A popular vertical antenna is the _____>
a. collinear
b. dipole
c. ground plane
d. broadside
396.
62. The discone antenna is
a. a useful direction-finding antenna
b. used as a radar receiving antenna
c. circularly polarized with other
circular antennas
d. useful as a UHF receiving antenna
397.
63. The feedpoint presents and ac load to the
transmission line called
a. antenna output impedance
b. antenna input impedance
c. feedpoint impedance
d. center feed impedance
398.
64. A helical antenna is used for satellite
tracking because of its
a. circular polarization
b. maneuverability
c. broad bandwidth
d. good front to back ratio
399.
65. The simplest type of antenna.
a. Elementary doublet
b. Half-wave dipole
c. Quarterwave dipole
d. 5/8 wavelength dipole
400.
66. Zoning is used with a dielectric antenna in
order to
a. reduce the bulk of the lens
b. increase the bandwidth of the lens
c. permit pin-point focusing
d. correct the curvature of the
wavefront from a horn that is too
short
401.
402.
403.
67. It is an electrically short dipole

a.
b.
c.
d.

short dipole
quarterwave dipole
half-wave dipole
yagi antenna

404.
68. Cassegrain feed is used with parabolic
reflector to
a. increase the gain of the system
b. increase the bandwidth of the system
c. reduce the size of the main reflector
d. allow the feed to be placed at a
convenient point
405.
69. The half-wave dipole is generally referred to
as ______.
a. Yagi antenna
b. Hertzian antenna
c. Marconi antenna
d. Hertz antenna
406.
70. Top loading is sometimes used with an
antenna in order to increase its
a. effective height
b. bandwidth
c. beamwidth
d. input capacitance
407.
71. What is the directivity of a Hertz antenna?
a. 1.64
b. 2.18
c. 2.15
d. 1.75
408.
72. The standard reference antenna for the
directive gain is the _______.
a. infinitesimal dipole
b. isotropic antenna
c. elementary doublet
d. half-wave dipole
409.
73. An antenna which is one-quarter wavelength
long, mounted vertically with the lower end
either connected directly to ground or
grounded through the antenna coupling
network.
a. loop antenna
b. hertzian dipole
c. monopole antenna
d. turnstile antenna
410.
411.
74. An antenna that is circularly polarized is the

a.
b.
c.
d.

helical
small circular loop
parabolic reflector
Yagi – Uda

412.
75. It is a wire structure placed below the
antenna and erected above the ground.
a. ground plane
b. counterpoise
c. ground lines
d. top hat
413.
76. Which of the following terms does not apply
to the Yagi-Uda array?
a. good bandwidth
b. parasitic elements
c. folded dipole
d. high gain
414.
77. It effectively cancels out the capacitance
component of the antenna input impedance.
a. ground plane
b. top hat
c. loading coil
d. shunt capacitance
415.
78. Indicate which of the following reasons for
the use of an earth mat with antenna is false:
a. impossibility of a good ground
conduction
b. provision of an earth for an antenna
c. protection of personnel working
underneath
d. improvement of the radiation pattern
of the antenna
416.
79. A metallic array that resembles a spoke
wheel placed at the top of an antenna, it
increases the shunt capacitance to ground
reducing the overall antenna capacitance.
a. loading coil
b. top loading
c. series capacitance
d. series inductors
417.
80. Indicate the antenna that is not wideband:
a. discone
b. folded dipole
c. helical
d. marconi
418.
81. It is formed when two or more antenna

elements are combined to form a single
antenna.
a. antenna elements
b. antenna array
c. driven elements
d. parasitic elements
419.
82. One of the following is not a reason for the
use of an antenna coupler:
a. to make the antenna look resistive
b. to provide the output amplifier with
the correct load impedance
c. to discriminate against harmonics
d. to prevent reradiation of local
oscillators
420.
83. It is an individual radiator, such as a half or
quarter-wave dipole.
a. antenna element
b. antenna array
c. reflector
d. director
421.
84. Indicate which of the following reasons for
using a counterpoise with antennas is false:
a. impossibility of a good ground
connection
b. protection of personnel working
underneath
c. provision of an earth for the antenna
d. rockiness of the ground itself
422.
85. Type of antenna element that is directly
connected to the transmission lines and
receives from or is driven by the source.
a. driven array
b. parasitic array
c. driven element
d. parasitic element
423.
86. Which of the following antennas is best
excited from a waveguide?
a. biconical
b. horn
c. helical
d. discone
424.
87. Type of antenna element that is not
connected to the transmission lines.
a. parasitic array
b. driven array
c. parasitic array

d. parasitic element
425.
88. One of the following is very useful as a
multi-band HF receiving antenna. This is
the:
a. conical horn
b. folded dipole
c. log-periodic
d. square loop
426.
89. A parasitic element that is longer than the
driven element from which it receives
energy.
a. driven element
b. director
c. parasitic elements
d. reflector
427.
90. One of the following consists of nonresonant antennas.
a. rhombic antenna
b. folded-dipole antenna
c. end-fire antenna
d. broadside antenna
428.
91. A parasitic element that is shorter than its
associated driven element.
a. redirector
b. director
c. reflector
d. parasitic element
429.
92. An ungrounded antenna near the ground.
a. acts as a single antenna near the
ground
b. is unlikely to need an earth mat
c. acts as an antenna array
d. must be horizontally polarized
430.
93. It is a non-resonant antenna capable of
operating satisfactorily over a relatively
wide bandwidth, making it ideally suited for
HF transmission.
a. turnstile antenna
b. loop antenna
c. rhombic antenna
d. discone antenna
431.
94. A wide – bandwidth multi-element driven
array is the ______.
a. end-fire
b. log-periodic

c. yagi
d. collinear
432.
95. It is a linear array antenna consisting of a
dipole and two or more parasitic elements:
one reflector and one director.
a. broadside antenna
b. end-fire antenna
c. yagi-uda antenna
d. phased array antenna
433.
96. An antenna which is consists of a cone that
is truncated in a piece of circular waveguide.
a. pyramidal horn antenna
b. circular horn antenna
c. rectangular horn antenna
d. circular horn antenna
434.
97. Which antenna has a unidirectional radiation
pattern and gain?
a. dipole
b. ground plane
c. yagi
d. collinear
435.
98. An antenna formed by placing two dipoles
at right angles to each other, 90 degrees out
of phase.
a. discone antenna
b. turnstile antenna
c. bicone antenna
d. 5/8 wavelength antenna
436.
99. The radiation pattern of collinear and a
broadside antenna is ________.
a. omnidirectional
b. bidirectional
c. unidirectional
d. clover-leaf shaped
100.
What is the bandwidth ration of logperiodic antenna?
a. 10:1
b. 5:1
c. 20:1
d. 1:10
437.
101.
Which beam width represents the
best antenna directivity?
a. 7 degrees
b. 12 degrees
c. 19 degrees

d. 28 degrees
438.
102.
It is the ratio of the highest to the
lowest frequency over which an antenna
will satisfactorily operate.
a. channel ratio
b. bandwidth ratio
c. reflection ratio
d. dynamic range
439.
103.
An antenna has a power gain off 15.
The power applied to the antenna is 32 W.
The effective radiated power is ________.
a. 15 W
b. 32 W
c. 120 W
d. 480 W
440.
104.
It is simply a single-turn coil of wire
that is significantly shorter than one
wavelength and carries RF current.
a. turnstile antenna
b. loop antenna
c. rhombic antenna
d. long-wire antenna
441.
105.
A coax has an attenuation of 2.4 dB
per 100 ft. The attenuation of 275 ft
a. 2.4 dB
b. 3.3 dB
c. 4.8 dB
d. 6.6 dB
442.
106.
It is group of antenna arrays that
when connected together, function as a
simple antenna whose beamwidth and
direction can be changed electronically
without having to physically move any of
the individual antennas or antenna
elements within the array.
a. end-fire array
b. broadside antenna
c. phased array antenna
d. log-periodic antenna
443.
107.
Conductors
in
multi-element
antennas that do not receive energy
directly from the transmission line are
known as ______.
a. parasitic element
b. driven element
c. the boom

d. receptor
444.
108.
It is a broadband VHF or UHF
antenna that is suited for applications for
which radiating circular rather than
horizontal
or
vertical
polarized
electromagnetic waves are required.
a. discone antenna
b. bicone antenna
c. log-periodic antenna
d. helical antenna
445.
109.
Mode of propagation of helical
antenna where electromagnetic radiation is
in the direction at right angles to the axis
of the helix.
a. normal mode
b. axial mode
c. helix mode
d. helical mode
446.
110.
Mode of propagation of helical
antenna where the radiation of the antenna
in the axial direction and produces a
broadband relatively directional pattern.
a. helical mode
b. normal mode
c. axial mode
d. helix mode
447.
111.
In a Yagi antenna, maximum
direction of radiation is toward the
a. director
b. driven element
c. reflector
d. sky
448.
112.
It is defined as the ratio of the
antennas maximum gain in the forward
direction to its maximum gain in its
backward direction
a. side-to-back ratio
b. front-to-side ratio
c. back-to-side ratio
d. front-to-back ratio
449.
113.
The horizontal radiation pattern of a
vertical dipole is a ____________.
a. figure of eight
b. circle
c. narrow beam
d. clover leaf

114.
An antenna that provides extremely
high gain and directivity and very popular
for microwave radio and satellite
communications link.
a. helical antenna
b. parabolic antenna
c. hyperbolic antenna
d. log-periodic antenna
450.
115.
Part of a parabolic antenna that
houses the primary antenna which radiates
electromagnetic waves toward the
reflector.
a. feed mechanism
b. focal point
c. center feed
d. feed antenna
451.
116.
It is a passive device that simply
reflects the energy radiated by the feed
mechanism into a concentrated, highly
directional emission in which the
individual waves are all in phase with each
other.
a. director
b. parabolic segment
c. reflector
d. feed mechanism
452.
117.
The energy near the edge of the
parabolic dish that does not reflect but
rather is diffracted around the edge of the
dish.
a. spillover
b. corona
c. dissipated power
d. copper loss
453.
118.
Determines the angular aperture of
the reflector, which indirectly determines
how much the primary radiation is
reflected by the parabolic dish.
a. numerical aperture
b. V number
c. aperture number
d. aperture angle
454.
119.
For a 2-m diameter parabolic
reflector with 10W of power radiated by
the feed mechanism operating at 6 GHz
with a transmit antenna efficiency of 55%
and an aperture efficiency of 55%,

determine the beamwidth.
a. 1.25 degrees
b. 2.25 degrees
c. 1.5 degrees
d. 1.75 degrees
455.
120.
Type of feed mechanism where the
primary radiating source is located just
behind a small opening at the vertex of the
paraboloid rather than at the focus.
a. cassegrain feed
b. center feed
c. horn feed
d. antenna feed
456.
121.
Discone radiation pattern is
a. omnidirectional
b. unidirectional
c. figure-of-eight
d. bidirectional
457.
122.
Which is properly terminated
antenna?
a. dipole
b. marconi
c. hertz
d. rhombic
458.
123.
An example of a marconi antenna is
_______.
a. quarter wave vertical tower
b. collinear
c. yagi
d. rhombic
459.
124.
At the ends of a half-wave antenna,
what values of current and voltage exist
compared to the remainder of the antenna?
a. minimum voltage and maximum
current
b. minimum voltage and minimum
current
c. equal voltage and current
d. maximum voltage and minimum
current
460.
125.
Radiation resistance is the ratio of
______.
a. radiated power to the antenna center
current
b. radiated power to the square of the
antenna center current

c. voltage to any point of the antenna
d. square of voltage to the square of
current at any point in the antenna
461.
126.
Consists of basic antenna connected
to a transmission line plus one or more
additional conductors
a. parasitic array
b. directors
c. driven array
d. reflectors
462.
127.
Which of the following is not a
driven array?
a. yagi
b. broadside
c. collinear
d. end fire
463.
128.
What is used to determine phase
difference
between
two
broadcast
antennas?
a. a phase monitor
b. a frequency monitor
c. an amplitude monitor
d. a power monitor
464.
129.
In antennas, which gives more
forward gain?
a. reflector
b. driven element
c. parasitic element
d. director
465.
130.
Which of the following is longer?
a. director
b. reflector
c. driven element
d. parasitic element
466.
131.
Which is closer to the driven
element?
a. parasitic element
b. driven element
c. director
d. reflector
467.
132.
How much do they differ in length
from a half-wavelength?
a. 5%
b. 10%
c. 15%

d. 20%
468.
133.
How
much
more
feed-point
impedance does a folded dipole have than
a normal dipole?
a. two times as much
b. three times as much
c. four times as much
d. five times as much
469.
134.
How is it possible to produce 70ohm twin lead?
a. by folding more parasitic element
b. by manufacturing
c. by increasing the radiation resistance
d. by increasing the length of the
antenna
470.
135.
With similar size parabolic, plane
reflector, and corner-reflector beams,
which has greater gain?
a. plane reflector
b. parabolic
c. corner-reflector beam
d. V-beam
471.
136.
With similar size, which has the
narrowest lobes?
a. parabolic
b. V-beam
c. corner-reflector beam
d. plane reflector
472.
137.
Why would the wires of V-beam be
closer together when used on higher
frequencies?
a. main lobe lays farther to wire
b. main lobe lays closer to wire
c. secondary lobes closer to wire
d. secondary lobes farther to wire
473.
138.
How the V-beam is made
unidirectional?
a. impedance terminated
b. capacitive terminated
c. inductive terminated
d. resistor terminated
474.
139.
Why might a rhombic be better than
a V-beam?
a. it is resistor terminated
b. more acreage needed

c. less acreage needed
d. it is unidirectional
475.
140.
Why is the usual rhombic not
frequency – sensitive?
a. unidirectional
b. with its characteristic impedance
c. less acreage required
d. main lobe is greater than back lobe
476.
141.
In what direction is the null of small
diameter loop in relation to the plane of
the loop?
a. 45 degrees angle
b. 180 degrees angle
c. 360 degrees angle
d. 90 degrees angle
477.
142.
When is a loop unidirectional?
a. when horizontal
b. when vertical
c. when circular
d. when unidirectional
478.
143.
Why are verticals sometimes toploaded?
a. to resonate on high frequency
b. to decrease the electrical length
c. to resonate on low frequency
d. to look better
479.
144.
Why is pi-network superior to direct
coupling to an antenna?
a. reduce harmonic radiation
b. better frequency response
c. better radiation of energy
d. reduce power dissipation
480.
145.
Why might L networks be used
between an antenna and transmission line?
a. step impedance up
b. step impedance down
c. better radiation of energy
d. reduce power radiation
481.
146.
Why are antenna ammeters often
shorted out or disconnected from the
antenna except when readings are desired?
a. to replace it with dummy
b. not to interface with transmission
c. for proper reception of signals
d. to protect from lightning

482.
147.
Device to split transmission line
current to two or more antenna towers
a. splitter
b. coupler
c. isolator
d. phasor circuit
483.
148.
What method can be used to
determine the feed-point impedance of a
vertical antenna?
a. resistance substitution
b. impedance matching
c. dissipated resistance measurement
d. grounding the antenna
484.
149.
In what unit is field intensity
measured?
a. volts
b. amperes
c. watts/m
d. mV/m
485.
150.
How fast does low-frequency field
strength attenuate?
a. directly proportional to distance
b. inversely proportional to distance
c. directly proportional to time
d. inversely proportional to time
486.
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568.

MULTIPLE CHOICE

569.
QUESTIONS
570.

571. IN
572.

573. ELECTRONICS SYSTEMS AND
TECHNOLOGIES (EST)
574.

575. Broadcast Engineering
576.

577. MELVIN C. ARCEO, ECE
578. PERC DC
579.
580.

581. ENCODED BY:
582.
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595.

BADILLO, AIMIE E.
583. 2006105942
584. ECE003/C11

1. In stereophonic broadcast, the center frequency of each SCA Subcarrier shall be kept at
all times within _______ Hz of the authorized frequency.
a. 200
b. 300
c. 400
d. 500
596.
2. Sawtooth generator circuits produce the scanning raster but the sync pulses are needed
for
a. linearity
b. timing
c. keystoning
d. line pairing
597.
3. Which of the following camera tubes has minimum lag?
a. Vidicon
b. Plumbicon
c. Saticon
d. Iconoscope
598.
4. The service are in standard AM broadcast is described as ______ if there is no fading of
signal.
a. Class A
b. Secondary
c. Class B
d. Primary
599.
5. The vertical field-scanning frequency is ______ Hz.
a. 30
b. 60
c. 525
d. 15,750
600.
6. A 4.5-MHz signal which is equal to the difference between the picture and sound RF
carrier frequencies in a 6-MHz TV channel.
a. Audio frequency
b. Video frequency
c. Intercarrier frequency
d. Subcarrier frequency
601.
7. A system where the modulated RF picture and sound carrier signals are distributed in a
cable network, instead of wireless system.
a. CCTV
b. MATV
c. CATV
d. SATV

602.
8. A class A FM station is limited in antenna height of ______ feet above average terrain.
a. 1000
b. 2000
c. 4000
d. 5000
603.
9. What circuit in the TV receiver is used to develop the high voltage needed to operate the
picture tube?
a. Low-voltage power supply
b. Horizontal output
c. Vertical sweep
d. Sync separator
604.
10. The modulated picture carrier wave includes the composite video signal as the
a. Average carrier level
b. Symmetric envelope of amplitude variations
c. Lower sideband without the upper sideband
d. Upper envelope without the lower envelope
605.
11. With which emission type is the capture-effect more pronounced?
a. CW
b. FM
c. SSB
d. AM
606.
12. The hue of color sync phase is
a. red
b. cyan
c. blue
d. yellow green
607.
13. How much is the equivalent internal resistance of the electron beam with a 1.2-mA beam
current at 25 kV?
a. 48 nano ohms
b. 30 ohms
c. 20.8 mega ohms
d. 15.6 kilo ohms
608.
14. The difference between the picture and sound carrier frequencies for channel 3 is ______
MHz.
a. 3.58
b. 64.5
c. 4.5
d. 6.75
609.

15. Refers to the deviation of the operating frequency of a crystal oscillator from its nominal
value due to temperature variations.
a. drift
b. flashover
c. frequency deviation
d. deviation ratio
610.
16. It is the measure of how many picture elements can be reproduced
a. definition
b. resolution
c. detail
d. any of these
611.
17. A 3.58-MHz subcarrier signal for color in television
a. Hue signal
b. Video signal
c. Audio signal
d. Chroma signal
612.
18. A class D FM station shall have an authorized power not exceeding ______ watts.
a. 20
b. 15
c. 10
d. 5
613.
19. Which of the following is not a benefit of cable TV?
a. Lower-cost reception
b. Greater stability
c. Less noise, stronger signal
d. Premium cable channels
614.
20. The width of the vertical sync pulse in the Philippine TV system is
a. 21H
b. 3H
c. H
d. 0.5H
615.
21. Term in communication which is referred, “to send out in all direction”
a. announce
b. broadcast
c. transmit
d. media
616.
22. The number of frames per second in the Philippine TV system is
a. 60
b. 262 ½

c. 4.5
d. 30
617.
23. It means multiple outlines of edges to the right in the picture.
a. ghosting
b. ringing
c. fading
d. snowing
618.
24. In the Sawtooth waveform for linear scanning,
a. the linear rise is for flyback
b. the complete cycle includes trace and retrace
c. the sharp reversal in amplitude produces trace
d. the beam moves faster during trace and retrace
619.
25. The purpose of pre-emphasis and de-emphasis in FM broadcasting is to:
a. increase the high frequency amplitude
b. improve the audio harmonic
c. decrease the low frequency amplitude
d. improve the S/N ratio
620.
26. The part of the visible spectrum where camera pickup tubes have the greatest output is
a. red
b. blue
c. yellow-green
d. infrared
621.
27. The type of modulation of the sound carrier signal is ______.
a. Pulse motion
b. Phase modulation
c. Amplitude modulation
d. Frequency modulation
622.
28. A video or audio signal that can be used directly to reproduce the picture and sound.
a. Baseband signal
b. Broadband signal
c. Electromagnetic wave signal
d. Modulated signal
623.
29. Class B FM station should have an ERP not exceeding ______ kW.
a. 50
b. 40
c. 30
d. 20
624.
30. What technique is used to permit hundreds of TV signals to share a common cable?

a.
b.
c.
d.

Frequency modulation
Mixing
Frequency division multiplexing
Time division multiplexing

625.
31. Another name for the horizontal retrace in a TV receiver is the
a. ringing
b. burst
c. damper
d. flyback
626.
32. In the Philippine color television system, the intercarrier frequency, in MHz, is
a. 3.58
b. 3.579645
c. 4.5
d. 45.75
627.
33. In channel 14 (470 to 476 MHz), the 3.58-MHz color signal is transmitted at
a. 471.25 MHz
b. 473.25 MHz
c. 474.83 MHz
d. 475.25 MHz
628.
34. Interlaced scanning eliminates
a. snowing
b. flicker
c. distortion
d. fading
629.
35. Beam alignment magnets for the camera tube are adjusted while rocking which color?
a. Optical focus
b. Electrical focus
c. Beam current
d. Shading
630.
36. What is a frequency discriminator?
a. An FM generator
b. A circuit for detecting FM
c. A circuit for filtering two closely adjacent signals
d. An automatic bandwidth circuit
631.
37. A system used in television field operation to make on-the-spot video tape recordings
using portable TV cameras and VTRs.
a. SNG
b. ENG
c. HAFC

d. MATV
632.
38. Class B FM station shall have an authorized transmitter power not exceeding ______ kW.
a. 10
b. 100
c. 1000
d. 10000
633.
39. The total bandwidth of an NTSC TV signal is
a. 3.58 MHz
b. 4.5 MHz
c. 6 MHz
d. 10.7 MHz
634.
40. Referred to the oscillator signal “leak through” from a property neutralized amplifier such
as a master oscillator power amplifier.
a. carrier
b. stray signal
c. back wave
d. loss wave
635.
41. Interlacing is used in television to
a. produce the illusion of motion
b. ensure that all lines on the screen are scanned, not merely the alternate ones
c. simply the vertical sync pulse train
d. avoid flicker
636.
42. Coaxial cable for distribution system has an impedance of
a. 50 ohms
b. 75 ohms
c. 150 ohms
d. 300 ohms
637.
43. The average voltage value of the 3.58-MHz modulated chrominance signal is
a. zero for most colors
b. close to black for yellow
c. the brightness of the color
d. the saturation of the color
638.
44. When does broadcast station conduct an equipment test?
a. during day time
b. during night time
c. during experimental period
d. at any time
639.
45. It causes the picture information to spread out or crowded at one end of the rater

compared to the opposite end.
a. Linear scanning
b. Interlaced scanning
c. Non-linear scanning
d. Retrace
640.
46. If the camera cannot be placed far away enough to include everything in the scene,
change the lens to one with a
a. lower f rating
b. higher f rating
c. longer focal length
d. shorter focal length
641.
47. Type of radio communication transmission utilizing frequency modulation technique
a. television video
b. broadcasting in 535-1606 kHz
c. single sideband HF transmission
d. television audio
642.
48. The amount of color in the picture or color intensity in the ______.
a. color level
b. chroma level
c. saturation
d. any of these
643.
49. One of the early radio transmitters which produced keyed carrier generating purer
waveform than spark transmitter, used for high powered RF transmission and are limited
to radio frequency of about 500 kHz.
a. Arc transmitter
b. Hartley transmitter
c. Spark transmitter
d. Frequency transmitter
644.
50. A technique where segments of videotape are joined by electronic erasing and recording
to create a single program.
a. masking
b. segmenting
c. editing
d. programming
645.
51. A class C FM station has an authorized power not exceeding ______watts of ERP.
a. 500
b. 750
c. 1000
d. 2000
646.

52. The assembly around the neck of a picture tube that produces the magnetic fields that
deflect and scan the electron beams is called the _________.
a. shadow mask
b. phosphor
c. electron gun
d. yoke
647.
53. An odd number of lines per frame form part of every one of the world’s TV systems. This
is _____________________.
a. done to assist interface
b. purely an accident
c. to ensure that line and frame frequencies can be obtained from the same original
source
d. done to minimize interference with the chroma subcarrier
648.
54. The difference between the sound carrier and the color signal is
a. 4.5 MHz
b. 1.25 MHz
c. 0.92 MHz
d. 0.25 MHz
649.
55. In color television, it is made for uniform color in the raster.
a. beam-landing adjustment
b. degaussing
c. internal blanking adjustment
d. background control
650.
56. Which of the following camera tubes uses lead oxide for the photoconductive target
plate?
a. vidicon
b. plumbicon
c. saticon
d. image orthicon
651.
57. The number of fields is ______ per frame.
a. 2
b. 60
c. 525
d. 262.5
652.
58. An RF carrier wave that is frequency – modulated by the baseband audio signal in TV
broadcasting.
a. Audio signal
b. Video signal
c. Intercarrier signal
d. Color signal

653.
59. A class B FM station is limited in antenna height of ____ feet.
a. 1000
b. 500
c. 250
d. 100
654.
60. The HV anode supply for the picture tube of a TV receiver is generated in the
a. mains transformer
b. vertical output stage
c. horizontal output stage
d. horizontal deflection oscillator
655.
61. A tap for the subscriber drop line has a
a. high insertion loss
b. high tap loss
c. low tap loss
d. 300-ohm impedance
656.
62. Which system can be used for both recording and playback?
a. CED
b. VHD
c. laser disk
d. VHS
63. The hue 180 degrees out of phase with red is ______.
a. cyan
b. yellow
c. green
d. blue
657.
64. It is used around the phosphor dots to make a darker black which improves contrast in the
picture.
a. black masking
b. convergence adjustment
c. shadow masking
d. color parity adjustment
658.
65. A lens with lower f rating is _____ lens that allows more light input.
a. slower
b. wider
c. narrower
d. faster
659.
66. Picture frames are repeated at the rate of ___ per second.
a. 30
b. 60

c. 45
d. 50
660.
67. The effective radiated power of a class A FM station should not exceed ______ kW.
a. 125
b. 30
c. 10
d. 1
661.
68. In television, 4:3 represents the
a. interface ratio
b. maximum horizontal deflection
c. aspect ratio
d. ration of the two diagonals
662.
69. Titling the viseo head gaps is necessary with the
a. color under
b. zero guard bands
c. FM luminance signal
d. Long – play tapes
663.
70. It is a special camera tube with a test pattern printed in the image plate.
a. vidicon
b. monoscope
c. oscilloscope
d. iconoscope
664.
71. The number of lines scanned per frame in the raster on the picture tube screen is
a. 525
b. 262 ½
c. 20
d. 10
665.
72. One of the following is a high powered RF ac basic transmitter that has two or more
stages, the oscillator stage which determines the frequency of operation and RF amplifier
stage or stages that develop the high power output. The purpose of which is to develop a
good frequency stability.
a. MOPA
b. Hartley
c. Alexanderson
d. Goldsmith
666.
73. Camera signal output without sync is called ______.
a. black burst
b. generator lock video
c. composite video

d. non-composite video
667.
74. The tint of the color is its _____.
a. brightness
b. contrast
c. chroma
d. hue
668.
75. Which frequency band is the standard AM radio broadcast?
a. HF
b. UHF
c. MF
d. VHF
669.
76. The I and Q composite color signals are multiplexed onto the picture carrier by
modulating a 3.58 MHz subcarrier using
a. FM
b. PM
c. DSB AM
d. Vestigial sideband AM
670.
671.
77. The shadow mask in color picture tube is used to
a. Reduce X-ray emission
b. Ensure that each beam hits only its dots
c. Increase screen brightness
d. Provide degaussing for the screen
672.
78. The video heads rotate at high velocity to increase the
a. tape speed
b. writing speed
c. reel rotation
d. tape tension
673.
79. How do you eliminate radio frequency variation of an oscillator transmitter caused by its
supply voltage?
a. use of a regulated power supply
b. use of a new power supply
c. use of high capacitor in the supply circuit
d. loosen power supply shielding
674.
80. The composite video signal includes the camera signal with the following except
a. picture information
b. sync pulses
c. blanking pulses
d. camera signal

675.
81. A lens has an 8-cm focal length and 4-cm diameter. Its f rating is
a. 2
b. 4
c. 8
d. 32
676.
82. Which of the following is a possible cause for an abrupt frequency variation in a self –
excited transmitter oscillator circuits resulting poor frequency stability to hold a constant
frequency oscillation?
a. DC and RF AC heating of resistor which cause a change in values
b. Heating and expansion of oscillator coil
c. Heating of capacitor in the oscillator
d. Power supply voltage changes
677.
678.
679.
83. How long does it take to scan 2 picture elements when 400 are scanned in 50
microseconds?
a. 25 microsec
b. 0.25 microsec
c. 2.5 microsec
d. 0.5 microsec
680.
84. Anode voltage for the picture tube, developed from the output of the horizontal deflection
circuit.
a. Yoke voltage
b. Flyback voltage
c. Aquadag voltage
d. Tube voltage
681.
85. The channel spacing in the Philippine FM broadcast standards
a. 400 kHz
b. 800 kHz
c. 600 kHz
d. 200 kHz
682.
86. What is the black-and-white or monochrome brightness signal in TV called?
a. RGB
b. Color subcarrier
c. Q an I
d. Luminance Y
683.
87. Which of the following is a midband cable TV channel?
a. 6
b. 7

c. 14
d. 23
684.
88. What is the primary purpose of an RF amplifier in a receiver?
a. to vary the receiver image rejection by utilizing the AGC
b. to provide most of the receiver gain
c. to develop the AGC voltage
d. to improve the receiver’s noise figure
685.
89. The color with the most luminance is
a. red
b. yellow
c. green
d. blue
686.
90. It is the light flux intercepted by a one-foot-square surface that is one-foot from a onecandlepower source.
a. candela
b. footcandle
c. lux
d. lumens
687.
91. Refers to the possible cause of an abrupt frequency variations in a self-excited transmitter
oscillator circuit resulting to a poor frequency stability to hold a constant oscillator.
a. poor soldered connections
b. heating of capacitor in the oscillator
c. DC and AC heating of resistors which cause change in values
d. Aging which cause change in condition in parts characteristics
688.
92. It is the difference in intensity between the black parts and white parts of the picture.
a. brightness
b. hue
c. contrast
d. illumination
689.
93. The stereophonic subcarrier suppression level in the Philippines standards
a. less than 4% modulation of the main carrier
b. less than 3% modulation of the main carrier
c. less than 2% modulation of the main carrier
d. less than 1% modulation of the main carrier
690.
94. The sound IF in a TV receiver is
a. 4.5 MHz
b. 10.7 MHz
c. 41.25 MHz
d. 45.75 MHz

691.
95. The circuit the separates sync pulse from the composite video waveforms is
a. the keyed AGC amplifier
b. a clipper
c. an integrator
d. a differentiator
692.
693.
96. In the CED system, the disk capacitance varies with the
a. pit depth
b. disk size
c. speed of rotation
d. wavelength of the scanning light
694.
97. The final power amplifier in an FM transmitter usually operates class ______.
a. AB
b. C
c. B
d. A
695.
98. In a picture tube, it is the total angle that the beam can be deflected without touching the
sides of the envelope.
a. screen angle
b. tube angle
c. picture angle
d. deflection angle
696.
99. It is necessary to time the scanning with respect to picture information
a. flyback
b. synchronization
c. blanking
d. scanning
697.
100. The intermediate frequency used in for FM broadcasting Philippine standards.
a. 455 kHz
b. 10.7 MHz
c. 11.4 MHz
d. 12.5 MHz
698.
699.
700.
701.

702. MULTIPLE CHOICE QUESTIONS IN:
703.
704.
705.

706.
707.

708. Test yourself- Exam 1-10
709. Noise Chapter 4
710. Antennas Chapter 6
711. Satellite Communications Chapter 10
712. Optical Fiber Communications
713. Broadcasting
714. Microwave Communications
715. Acoustics
716. Radiation and wave propagation
717. Transmission Fundamentals
718. Wire and Wireless Communications – Chapter 7
719. Modulation – Chapter 3
720.
721.
722.

723. Encod
ed By:
725. Garcia,
Frederick P.
726. Cagaoan, Neil
727. Mendoza,
Darren
728. Puro, Genara
Mhariz P.
729. Tan, Virson V.
730. Visaya, Luz
Regine B.
731.

Test Yourself –Exam 01
732. ECE Board Exam March 1996
733. That dielectric material of an optical fiber surrounding the core
734. Cladding
735. Armor
736. Shield
737. Cover
738. ECE Board Exam March 1996

724.

739. An antenna that is circularly polarized is the ____________.
740. parabolic reflector
741. helical
742. Yagi-uda
743. small circular loop
744. ECE Board Exam March 1996
745. A word in telegraphy consist of __________ characters plus a word space.
746. 11
747. 7 and ½
748. 8
749. 5
750. ECE Board Exam March 1996
751. The number of voice band channels in master group per CCITT standard is __________.
752. 300
753. 480
754. 600
755. 120
756. ECE Board Exam March 1996
757. The power of standard test tone is normally ____________.
758. 1 dB
759. 0 mW
760. 1 mW
761. 1 W
762. ECE Board Exam March 1996
763. LORAN is a navigational system used primarily for _____________.
764. blind landing
765. obtaining your fixes location over large distances
766. automatic collision warning
767. approach control
768. ECE Board Exam March 1996
769. The expander in a companding device provides ___________.
770. greater amplification for low signal levels
771. less amplification for low signal levels
772. greater amplification for high signal levels
773. lesser pressure for transmission cables
774. ECE Board Exam March 1996
775. LORAN is a navigation system used primarily for
776. approach control
777. obtaining fixes over large distances
778. blind landing
779. automatic collision warning
780. ECE Board Exam March 1996
781. At what power level does a 1 kHz tone cause zero interference (144 weighted) ?
782. -90 dB
783. -90 dBm
784. 90 dBm

785. 90 dB
786. ECE Board Exam March 1996
787. One character or a sequence of characters forming a part, or the whole of a message with
a specific meaning
788. Signs
789. Call sign
790. Code
791. Identifier
792. ECE Board Exam March 1996
793. The K-factor under normal atmospheric conditions in a microwave radio data profile
calculation is equal to ___________.
794. 2/3
795. 0
796. 4/3
797. Infinity
798. ECE Board Exam March 1996
799. What is the IBM’s asynchronous data link protocol designation?
800. 83 B
801. 8A1 / 8B1
802. 93 B
803. 9A1/ 9B1
804. ECE Board Exam March 1996
805. EIRP stands for _______________.
806. effective isotropic refracted power
807. effective and ideal radiated power
808. effective isotropic reflected power
809. effective isotropic radiated power
810. ECE Board Exam March 1996
811. The modulation system used for telegraphy is
812. frequency-shift keying
813. two-tone modulation
814. pulse-code modulation
815. single-tone modulation
816. ECE Board Exam March 1996
817. The standard that specifies a balanced interface cable that will operate bit rates up to 10
Mbps with in a span distances up to 1200 m.
818. RS-423A
819. RS-422A
820. RS-550A
821. RS-449A
822. ECE Board Exam March 1996
823. An antenna which is not resonant at a particular frequencies and so can be used over a
wide band of frequencies and so can be used over a wide band of frequencies is called
824. aperiodic
825. boresight
826. cassegrain

827. top-loaded
828. ECE Board Exam March 1996
829. A receiver connected to an antenna whose resistance is 50 ohms has an equivalent noise
resistance of 30 ohms. What is the receiver’s noise temperature?
830. 754 K
831. 464 K
832. 174 K
833. 293 K
834. ECE Board Exam March 1996
835. ___________ occurs when the microwave beam is at point of grazing over an obstacle.
836. Diffraction
837. Refraction
838. Absorption
839. Reflection
840. ECE Board Exam March 1996
841. Atmospheric condition is controlled by
842. humidity
843. pressure
844. temperature
845. all of these
846. ECE Board Exam March 1996
847. The characteristics impedance of a transmission line does not depend upon its
________.
848. conductor spacing
849. conductor diameter
850. length
851. conductor radius
852. ECE Board Exam March 1996
853. What is the purpose of a beat frequency oscillator (BFO)?
854. Aid in the reception of weak voice-modulated signals
855. Generates a signal, whose frequency is the same as that of the intermediate
frequency
856. Generates a 1kHz note for Morse code reception
857. Generates an output, whose frequency differs from that of the intermediate
frequency by 1 kHz
858. ECE Board Exam March 1996
859. The point on the satellite orbit, closest to the earth is
860. prograde
861. perigee
862. zenith
863. apogee
864. ECE Board Exam March 1996
865. The potential difference between any exposed structured to ground in any electrical
installation should not exceed _________ volts RMS.
866. 10
867. 45

868. 0
869. 30
870. ECE Board Exam March 1996
871. The capture area of an antenna is directly proportional to the
872. frequency of the received signal
873. distance between transmitter and receiver
874. gain of the antenna
875. power density of the signal
876. ECE Board Exam March 1996
877. Modems are required to connect computer to telephone lines because ___________.
878. telephone company rules required them
879. the telephone network bandwidth is too high
880. none of the above
881. the telephone network will pass direct current
882. ECE Board Exam March 1996
883. The standard reference antenna for the directive gain is ___________.
884. elementary doublet
885. isotropic antenna
886. half-wave dipole
887. infinitesimal dipole
888. ECE Board Exam March 1996
889. One hundred twenty µbars of pressure variation is equal to
890. 120 dBSPL
891. 115.56 dBSPL
892. 41.58 dBSPL
893. 57.78 dBSPL
894. ECE Board Exam March 1996
895. It is a spacecraft placed in orbit around the earth carrying onboard microwave receiver
and transmitting equipments.
896. Fiber optic equipment
897. Communications satellite
898. Wireless radio system
899. Coaxial cable syste
900. ECE Board Exam March 1996
901. One type of pulse communications system uses pulse that appear as a group, and which
vary in number according to the loudness of the voice. This type of pulse modulation is
called
902. pulse duration modulation
903. pulse amplitude modulation
904. pulse code modulation
905. pulse position modulation
906. ECE Board Exam March 1996
907. A device to be connected across the headset in telephone receivers to reduce the effects
of acoustic shock.
908. Ground
909. Two rectifiers in parallel with opposite polarities

910. Protector
911. Fuse
912. ECE Board Exam March 1996
913. Judgment on the case against an ECE shall become final and executory after
914. 10 days
915. 60 days
916. 30 days
917. 15 days
918. ECE Board Exam March 1996
919. The equivalent noise temperature of the amplifier is 25 K. What is the noise figure?
920. 1.86
921. 0.1086
922. 1.086
923. 10.86
924. ECE Board Exam March 1996
925. The letter-number designation B8E is a form of modulation also known as
___________.
926. pilot carrier system
927. independent sideband emission
928. lincomplex
929. vestigial sideband transmission
930. ECE Board Exam March 1996
931. When the transmitting and receiving antennas are in line-of-sight of each other, the
mode of propagation is ________ wave.
932. space or direct
933. ground
934. surface
935. sky
936. ECE Board Exam March 1996
937. Crosstalk coupling is ___________.
938. dBm (disturbing pair) minus dBm (disturbed pair)
939. the difference between readings on a cable pair with a tone and a cable pair
without tone read at the far end of a cable
940. signals from one circuit that get into another circuit
941. All of these are true
942. ECE Board Exam March 1996
943. According to the Nyquist theorem, the sampling rate that can be used in a PCM system
is ________ the highest audio frequency.
944. once
945. eight times
946. twice
947. thrice
948. ECE Board Exam March 1996
949. Passive crossover components cause some frequencies to be delayed with respect to the
other frequencies at the crossover point.
950. Phase shift

951. Phase correction
952. Phase-error correction
953. Time alignment
954. ECE Board Exam March 1996
955. A car horn outdoors produces a sound intensity level of 90 dB at 10 ft away. At this
distance, what is the sound power in watt?
956. 12 W
957. 0.12 W
958. 0.012 W
959. 1.2 W
960. ECE Board Exam March 1996
961. What is the one principal difference between synchronous and asynchronous
transmission?
962. the pulse height are different
963. the clocking is derived from the data in synchronous transmission
964. the clocking is mixed with the data in asynchronous
965. the bandwidth required is different
966. ECE Board Exam March 1996
967. The lowest layer in the ionosphere
968. D
969. F2
970. E
971. F1
972. ECE Board Exam March 1996
973. What is the number of pins in the RS-232C interface?
974. 25
975. 15
976. 20
977. 20
978. ECE Board Exam March 1996
979. SSB transmission requires only ______ of the bandwidth for a DSBFC transmission.
980. ¼
981. 2/3
982. ½
983. ¾
984. ECE Board Exam March 1996
985. The method of generating FM used by broadcasting station is
986. direct
987. all of these
988. indirect
989. insertion
990. ECE Board Exam March 1996
991. What is the transmission rate of a system for transmitting the output of a microcomputer
to a line printer operating at a speed of 30 lines/minute? Assume that the line printer has 8
bits of data per character and prints out 80 characters/line.
992. 800 bps

993. 400 bps
994. 320 bps
995. 640 bps
996. ECE Board Exam March 1996
997. Communications code is ____________.
998. eight bits per character
999. agreed upon in advance between sender and receiver
1000. the same in all modern computers
1001. either seven or eight bits per character
1002.
ECE Board Exam March 1996
1003.
What is the reference tone level for dBm?
1004. -82 dBm
1005. -85 dBm
1006. -67 dBm
1007. -90 dBm
1008.
ECE Board Exam March 1996
1009.
A type of an underground antenna is a/an __________ antenna.
1010. Hertz
1011. isotropic
1012. parabolic
1013. Marconi
1014.
ECE Board Exam March 1996
1015.
Which of the following pulse modulation systems is analog?
1016. Delta
1017. Differential PCM
1018. PWM
1019. PCM
1020.
ECE Board Exam March 1996
1021.
What is the purpose of the receiver’s squelch circuit?
1022. To overcome fluctuations in the level the RF signal arriving at the receiver
antenna
1023. To prevent fluctuations in the AGC bias level
1024. To reduce the receiver’s sensitivity to all incoming signals
1025. To prevent amplified noise from reaching the loudspeaker during the absence
of an incoming signal
1026.
ECE Board Exam March 1996
1027.
TACAN is a navigational aid providing ___________.
1028. bearing and distance indication
1029. speed and height indication
1030. bearing and weather information
1031. instrument-landing glide paths
1032.
ECE Board Exam March 1996
1033.
In __________ transmission, a unique SYNC character is transmitted at the
beginning of each message.
1034. asynchronous
1035. synchronous

1036. digital
1037. analogue
1038.
ECE Board Exam March 1996
1039.
If the terminating impedance is exactly equal to the characteristic impedance of
the transmission line the return loss is ___________.
1040. zero
1041. one
1042. infinite
1043. None of these
1044.
ECE Board Exam March 1996
1045.
What is the main purpose of a communications system?
1046. None of these
1047. To have a frequency assignment
1048. For modulation
1049. To provide an acceptable replica of the information at the destination
1050.
ECE Board Exam March 1996
1051.
What is meant by antenna gain?
1052. The final amplifier gain minus the transmission line losses (including any phasing
lines present)
1053. The ratio of the amount of power produced by the antenna compared to the output
power of the transmitter
1054. The ratio of the signal in the backward direction
1055. The numeric ratio relating the radiated signal strength of an antenna to that
of another antenna
1056.
ECE Board Exam March 1996
1057.
Binary communications systems are better because
1058. they can interface directly with the analog telephone network
1059. the components are simpler, less costly, and more reliable
1060. people think better in binary
1061. interstate calls are less costly
1062.
1063.
ECE Board Exam March 1996
1064.
In the phase shift method, How many circuits must be balanced?
1065. None of these
1066. 1
1067. 4
1068. 2
1069.
ECE Board Exam March 1996
1070.
The carrier swing necessary to provide 80% modulation in the FM broadcasting
band is __________.
1071. 150 kHz
1072. 120 kHz
1073. 60 kHz
1074. 75 kHz
1075.
ECE Board Exam March 1996
1076.
The correctness and accuracy of the transmitted message content is

1077. verified by the modem
1078. communications system
1079. determined by the sender and receiver
1080. ensured by use of digital technique
1081.
ECE Board Exam March 1996
1082.
The signal in a channel is measured to be 23 dB while noise in the same channel
is measured to be 9 dB. The signal to noise ratio therefore is __________.
1083. 9/23
1084. 23/9
1085. 32 dB
1086. 14 dB
1087.
ECE Board Exam March 1996
1088.
Three audio waves with 100,200 and 300 volts amplitude respectively,
simultaneously modulate a 450 volts carrier. What is the total percent of modulation of
the AM wave?
1089. 69 %
1090. 115.5 %
1091. 50%
1092. 83%
1093.
ECE Board Exam March 1996
1094.
If the percentage modulation of an AM amplifier is 88% and the modulating
signal is 1 volt, the carrier has an amplitude of _______________.
1095. 1.14 volts
1096. 0.88 volt
1097. 1.88 volts
1098. 0.12 volt
1099.
ECE Board Exam March 1996
1100.
It consists of a number of dipoles of equal size, equally spaced along a straight
line with all dipoles fed in the same phase from the same source.
1101. Log-periodic antenna
1102. Yagi antenna
1103. End-fire array
1104. Broadside array
1105.
ECE Board Exam March 1996
1106.
Data switching systems.
1107. improve the efficiency of data transfer
1108. are limited to small data networks
1109. required additional lines
1110. are not used in data system
1111.
ECE Board Exam March 1996
1112.
A type of array antenna which consists of one half-wave driven dipole, one
reflector and one director
1113. Hertzian dipole
1114. Yagi-uda
1115. Broadside collinear
1116. Log periodic dipole array

1117.
ECE Board Exam March 1996
1118.
Power is a _____________ amount of energy used in specific period of time
1119. large
1120. definite
1121. electrical
1122. relative
1123.
ECE Board Exam March 1996
1124.
The midrange frequency range of sound is from
1125. 256 to 2048 Hz
1126. 2048 to 4096 Hz
1127. 512 to 2048 Hz
1128. 16 to 64 Hz
1129.
ECE Board Exam March 1996
1130.
To connect coaxial line to a parallel-wire _________ is the best to use.
1131. directional coupler
1132. quarter-wave transformer
1133. balun
1134. slotted line
1135.
ECE Board Exam March 1996
1136.
In AM, the carrier carries ____________ intelligence.
1137. no
1138. difference
1139. distorted
1140. same
1141.
ECE Board Exam March 1996
1142.
Characteristics impedance of a transmission line is the impedance measured at the
___________ when its length is infinite.
1143. input
1144. shorted end of the line
1145. output
1146. midsection
1147.
ECE Board Exam March 1996
1148.
Cross modulation on a receiver is eliminated at the
1149. RF stage
1150. mixer stage
1151. IF stage
1152. detector stage
1153.
ECE Board Exam March 1996
1154.
A speaker cabinet has an internal volume 84,950 cm3. It has a port area on the
baffle of 3,230 cm2 and baffle thickness of 19 mm. What is the Helmholtz resonance
hertz of this speaker enclosure?
1155. 260 Hz
1156. 245 Hz
1157. 265 Hz
1158. 250 Hz
1159.
ECE Board Exam March 1996

1160.
What quarterwave transformer will match a 100Ω line to an antenna whose value
is 175Ω?
1161. 132.29 Ω
1162. 150 Ω
1163. 16.58 Ω
1164. 137.5 Ω
1165.
ECE Board Exam March 1996
1166.
The local loop of the telephone system is understood to be
1167. a single piece of wire connecting the subscriber’s telephone set to another
telephone set in an adjacent room
1168. a two-wire or four-wire communication circuit between the customer’s
premise and central office
1169. a four-wire circuit connecting a facsimile machine to a computer
1170. a group of wires connecting a telephone set to a modem
1171.
ECE Board Exam March 1996
1172.
In what region of the world is sporadic-E most prevalent?
1173. The equatorial regions
1174. The northern hemisphere
1175. The arctic regions
1176. The polar regions
1177.
ECE Board Exam March 1996
1178.
The process of assigning PCM codes to absolute magnitudes
1179. Overloading
1180. All of these
1181. Quantizing
1182. Multiplexing
1183.
ECE Board Exam March 1996
1184.
It is a measure of the microwave power radiated from an antenna as a function of
angular direction from the antenna axis.
1185. Antenna pattern
1186. Polarization
1187. Beamwidth
1188. Sidelobes
1189.
ECE Board Exam March 1996
1190.
It is the made from semiconductor material such as aluminum-galium-arsenide or
gallium-arsenide-phosphide.
1191. APD
1192. Injection laser diode
1193. Light emitting diode
1194. Positive-intrinsic-negative
1195.
ECE Board Exam March 1996
1196.
Which one is not the basic electrical protection measures in the Philippine
Electronics Code?
1197. Voltage/ current limiting and interrupting
1198. Undergrounding
1199. Grounding and bonding

1200. Shielding
1201.
ECE Board Exam March 1996
1202.
What does the noise weighting curve shows?
1203. Noise signals measured with a 144 handset
1204. Power levels of noise found in carrier systems
1205. The interfering effect of other frequencies in a voice channel compared with
a reference frequency of one kilohertz
1206. Interfering effects of signals compared with a 3-kHz tone
1207.
ECE Board Exam March 1996
1208.
What is the difference between phase and frequency modulation?
1209. Is purely theoretical because they are the same in practice
1210. Lies in poorer audio response of phase modulation
1211. Lies in the different definitions of the modulation index
1212. Is too great to make two systems compatible
1213.
ECE Board Exam March 1996
1214.
When a transmission line uses ground return, it is called a/an __________ line.
1215. ungrounded
1216. balanced
1217. unbalanced
1218. grounded
1219.
ECE Board Exam March 1996
1220.
What is the gain of four identically polarized antennas stacked one above the
other and fed in phase?
1221. 3 dB over the gain of one antenna
1222. 10 dB over the gain of one antenna
1223. 4 dB over the gain of one antenna
1224. 6 dB over the gain of one antenna
1225.
ECE Board Exam March 1996
1226.
The ratio of the level of the modulated output of a transmitter under conditions of
standard test modulation to the level of the demodulated output with no modulation
applied both measured with the same bandwidth.
1227. Reference audio output
1228. None of these
1229. Audio frequency response
1230. Residual noise level
1231.
ECE Board Exam March 1996
1232.
The ___________ filter attenuates signals but passes frequencies below and above
that band.
1233. low pass
1234. band pass
1235. band stop
1236. high pass
1237.
ECE Board Exam March 1996
1238.
In a telephone system, the customer’s telephone directory numbering is from 000
to 999, what is the capacity of the system?
1239. 1000 lines

1240. 100,000 lines
1241. 10,000 lines
1242. 100 lines
1243.
ECE Board Exam March 1996
1244.
An absorption loss caused by valence electrons in the silica material from which
fibers are manufactured.
1245. Modal dispersion
1246. Infrared absorption
1247. Ion resonance absorption
1248. Ultraviolet absorption
1249.
ECE Board Exam March 1996
1250.
In an FM receiver, which circuit removes amplitude variations?
1251. Exciter
1252. Mixer
1253. Discriminator
1254. Limiter
1255.
ECE Board Exam March 1996
1256.
A one-hop, full duplex, microwave system in a space diversity arrangement.
Determine “how many receivers in all are used?”
1257. 8
1258. 2
1259. 4
1260. 6
1261.
ECE Board Exam March 1996
1262.
The frequency spectrum of the stereophonic FM signal.
1263. 67 kHz
1264. 59.5 to 74.5 kHz
1265. 19 to 38 kHz
1266. 30 to 53 kHz
1267.
ECE Board Exam March 1996
1268.
Termination means
1269. result of disconnecting a line from a transmitter
1270. result of cutting both ends of a conductor
1271. looking back impedance of a line with no load
1272. load connected to the output end of a transmission line
1273.
ECE Board Exam March 1996
1274.
Asynchronous protocol is
1275. message oriented
1276. clock oriented
1277. bit oriented
1278. character oriented
1279.
ECE Board Exam March 1996
1280.
Transmission lines are either balanced or unbalanced with respect to _________.
1281. negative terminal
1282. input
1283. ground

1284. positive terminal
1285.
ECE Board Exam March 1996
1286.
What is the velocity factor for non-foam dielectric 50 or 75 ohm flexible coaxial
cable such as RG 8, 11, 58 and 59?
1287. 2.70
1288. 0.10
1289. 0.66
1290. 0.30
1291.
ECE Board Exam March 1996
1292.
Gain of an isotropic antenna
1293. -1 dB
1294. 1 dB
1295. 0 dB
1296. 2 dB
1297.
ECE Board Exam March 1996
1298.
In measuring noise in a voice channel at a 4 dB test point level, the meter reads
-70 dBm (F1A weighted), convert the reading to pWp.
1299. 53
1300. 93
1301. 63
1302. 83
1303.
ECE Board Exam March 1996
1304.
Power is always __________.
1305. a definite amount of energy
1306. all of these
1307. the rate at which energy is used
1308. expressed in watts
1309.
ECE Board Exam March 1996
1310.
Radio fading resulting from obstruction losses.
1311. Log normal fading
1312. None of these
1313. Multi-path fading
1314. Rayleigh fading
1315.
ECE Board Exam March 1996
1316.
After the IF stages have been aligned, the next stage to align in FM receiver is.
1317. local oscillator
1318. limiter stage
1319. RF amplifier
1320. mixer stage
1321.
ECE Board Exam March 1996
1322.
___________ is a device in data transmission to interface data terminal equipment
to an analogue transmission line.
1323. RS 232
1324. Connector
1325. Modem
1326. RJ-11 plug

1327.
1328.
1329.
1330.
1331.
1332.
1333.

ECE Board Exam March 1996
What is the primary advantage of DSBSC in AM?
Reduce bandwidth over standard AM
All of these
It is simpler to transmit and receive than the standard AM
No transmitter power is wasted in the carrier

1334.
1335.
1336.
1337.
1338.
1339.
1340.
1341.
1342.
1343.
1344.
1345.
1346.
1347.
1348.
1349.
1350.
1351.
1352.
1353.
1354.
1355.
1356.
1357.
1358.
1359.
1360.
1361.
1362.
1363.
1364.
link.
1365.
1366.
1367.
1368.
1369.
1370.

Test Yourself – Exam 02
ECE Board Exam November 1996
Which frequency band is the standard AM radio broadcast?
HF
UHF
MF
VHF
ECE Board Exam November 1996
A system that performs parallel-to-serial and serial-to-parallel conversion of data
DCE
DTE
Modem
PC
ECE Board Exam November 1996
The line control unit (LCU) operates on the data digital form.

1371. Data communications equipment (DCE)
1372. UART
1373. Modem
1374. Data terminal equipment (DTE)
1375.
ECE Board Exam November 1996
1376.
Quantization noise is caused by
1377. binary coding techniques
1378. serial transmission errors
1379. the synchronization between encoder and decoder
1380. the approximation of the quantized signal
1381.
ECE Board Exam November 1996
1382.
Speaker is a device that __________.
1383. convert current variations into sound waves
1384. none of these
1385. convert electrical energy to mechanical energy
1386. convert sound waves into current and voltage
1387.
ECE Board Exam November 1996
1388.
An object farther from a converging lens than its focal point always has an
_______ image.
1389. virtual
1390. the same in size
1391. inverted
1392. smaller size
1393.
ECE Board Exam November 1996
1394.
The loss in signal power as light travels down a fiber is
1395. attenuation
1396. propagation
1397. absorption
1398. scattering
1399.
ECE Board Exam November 1996
1400.
Energy that has neither been radiated into space nor completely transmitted.
1401. Captured waves
1402. Incident waves
1403. Standing waves
1404. Modulated waves
1405.
ECE Board Exam November 1996
1406.
One of the reasons why FDM is being replaced by TDM is
1407. noise is amplified with voice when an FDM system is used
1408. it is difficult to place channels side by side
1409. there is more time than frequency
1410. Most available frequencies has been used
1411.
ECE Board Exam November 1996
1412.
Which determines the number of sideband components of FM?
1413. Modulation frequency
1414. Modulation index
1415. Carrier frequency

1416. All of these
1417.
ECE Board Exam November 1996
1418.
How would one squeeze more channels of communication into TDM frames of
standard length?
1419. Shorten the time delay for each channel
1420. Raise the amplitude
1421. Add modulators
1422. Remove the synchronizing pulses
1423.
ECE Board Exam November 1996
1424.
When one stations is designated as master and rest of the stations are considered
slaves message handling is ________.
1425. polling
1426. WAN
1427. LAN
1428. OSI
1429.
ECE Board Exam November 1996
1430.
How many satellite orbital slots are requested by the Philippine government from
ITU?
1431. 2
1432. 6
1433. 5
1434. 3
1435.
ECE Board Exam November 1996
1436.
The output of a balanced modulator is ____________.
1437. LSB and USB
1438. LSB
1439. USB
1440. Carrier
1441.
ECE Board Exam November 1996
1442.
RS-232, RS-449, RS-530, V, 24 and X.21 are examples of ____________.
1443. standards for interfaces between modems and transmission facilities
1444. standards for various types of transmission channels
1445. standards for interfaces between terminals and modems
1446. standards for end to end performance of data communications system
1447.
ECE Board Exam November 1996
1448.
A special service circuit connecting two private branch exchanges (PBX).
1449. Phantom line
1450. Private line
1451. Tie trunk
1452. Tandem trunk
1453.
ECE Board Exam November 1996
1454.
What is the baseband frequency of standard FDM basic supergroup?
1455. 312 to 552 kHz
1456. 300 to 600 kHz
1457. 60 to 2540 kHz
1458. 60 to 108 kHz

1459.
ECE Board Exam November 1996
1460.
What is the data rate of the ISDN Basic access B channel?
1461. 192 kbps
1462. 32 kbps
1463. 64 kbps
1464. 144 kbps
1465.
ECE Board Exam November 1996
1466.
Which tester is used to measure SWR?
1467. Spectrum analyzer
1468. Multimeter
1469. Reflectometer
1470. Oscilloscope
1471.
ECE Board Exam November 1996
1472.
What is the transmission rate of a GSM cellular system?
1473. 64 kbps
1474. 240 kbps
1475. 128 kbps
1476. 270 kbps
1477.
ECE Board Exam November 1996
1478.
A dipole antenna requires to be feed with 20 kW of power to produce a given
signal strength to a particular distant point. If the addition of a reflector makes the same
field strength available with an input power of 11 kW. What is the gain in dB obtain by
the use of the reflector ? ( Gain referred to this particular dipole)
1479. 4.24
1480. 1.81
1481. 4.75
1482. 2.6
1483.
ECE Board Exam November 1996
1484.
Pulse carrier at the ratio of 8000 pulse/sec is amplitude modulated by an analog
signal this type of modulation is
1485. PAM
1486. ADM
1487. DM
1488. PCM
1489.
ECE Board Exam November 1996
1490.
What is the applied power if a thermal RF wattmeter is connected to a transmitter
through a variable attenuator? The wattmeter reads 84 mW when 15 dB of attenuation is
used.
1491. 4.656 watts
1492. 2.656 watts
1493. 3.656 watts
1494. 2.856 watts
1495.
ECE Board Exam November 1996
1496.
Collects very weak signal from a broadcast satellite
1497. Satellite dish
1498. LNB

1499. Yagi-Uda antenna
1500. Satellite receiver
1501.
ECE Board Exam November 1996
1502.
A seven-bit character can represent one of _________ possibilities.
1503. 14
1504. 64
1505. 128
1506. 7
1507.
ECE Board Exam November 1996
1508.
The maximum power suggested by KBP on 919-1312 AM broadcast station in
Metro Manila is
1509. 10 kW
1510. 20 kW
1511. 15 kW
1512. 5 kW
1513.
ECE Board Exam November 1996
1514.
A loudspeaker cabinet has an internal volume of 5,184 in3 (84,950 cm3). It has a
port area on the baffle of 50 in2 (322.58cm2) and a thickness of 0.70 in (18 mm). What is
the Helmholtz resonance, in hertz, of this loudspeaker enclosure?
1515. 250 Hz
1516. 245 Hz
1517. 240 Hz
1518. 255 Hz
1519.
ECE Board Exam November 1996
1520.
When the clearance above the obstruction is equal to the radii of even Fresnel
zone at the point of reflection the RSL
1521. remains the same
1522. is above threshold
1523. is decreased
1524. is increased
1525.
ECE Board Exam November 1996
1526.
Digital transmission provides a higher level of signal quality than analog
transmission because
1527. repeaters regenerate digital pulses and remove distorstion
1528. digital signals are easier to sample than analog signals
1529. digital signals are smaller than analog signals and cannot easily be distorted
1530. analog signals are continuous and not easily distorted.
1531.
ECE Board Exam November 1996
1532.
A _________ interconnects LAN having identical protocols at the physical and
data link layers.
1533. All of these
1534. bridge
1535. router
1536. Gateway
1537.
ECE Board Exam November 1996
1538.
Both frequency and phase modulation utilize ________ modulation

1539. Phase
1540. AM and FM
1541. Digital
1542. Angle
1543.
ECE Board Exam November 1996
1544.
The different angles of entry of light into an optical fiber when the diameter of the
core is many times the wavelength of the light transmitter is known as ________.
1545. refraction
1546. sensor
1547. mode
1548. emitter
1549.
ECE Board Exam November 1996
1550.
An invitation from the primary to a secondary to transmit a message.
1551. Retransmission
1552. Selection
1553. Reuse
1554. Polling
1555.
ECE Board Exam November 1996
1556.
An agency of the United Nations that formulates standards and recommend
practices for all civil aviation
1557. ICAO
1558. CAA
1559. IATA
1560. ATO
1561.
ECE Board Exam November 1996
1562.
The transformer signal coding method for T1 carrier is
1563. Binary
1564. NRZ
1565. Manchester
1566. Bipolar
1567.
ECE Board Exam November 1996
1568.
When the value of k increases, the effective result is ______ of the equivalent
curvatures.
1569. downward curvatures
1570. flattening
1571. bulging
1572. sharp curvature
1573.
ECE Board Exam November 1996
1574.
An electromagnetic wave consists of
1575. a magnetic field only
1576. both electric and magnetic fields
1577. an electric field only
1578. non-magnetic field only
1579.
ECE Board Exam November 1996
1580.
In a transmission line, if the maximum current to minimum current ratio is 2:1
what is the ratio of the maximum voltage to minimum voltage?

1581.
1582.
1583.
1584.
1585.
1586.
1587.
1588.
1589.
1590.
1591.
1592.
1593.
1594.
1595.
1596.
1597.
1598.
1599.
1600.
1601.
1602.
1603.
1604.
1605.
1606.
1607.
1608.
1609.
1610.
1611.
1612.
1613.
1614.
1615.
1616.
1617.
1618.
1619.
1620.
1621.
1622.
1623.
1624.
1625.
1626.

4:1
1:2
1:4
2:1
ECE Board Exam November 1996
Satellite signal transmitted from a satellite transponder to earth’s station.
Vertically polarized
Uplink
Downlink
RHCP
ECE Board Exam November 1996
Multiplexing scheme use by baseband transmission.
FDM
Space multiplexing
TDM
Statistical multiplexing
ECE Board Exam November 1996
Which stands for dB relative level?
dBrn
dBm
dBr
dBa
ECE Board Exam November 1996
What is the maximum color TV bandwidth?
1.6 MHz
0.5 MHz
1.0 MHz
1.3 MHz
ECE Board Exam November 1996
If Ns=250, determine the earth radius k-factor.
1.98
1.23
1.33
1.29
ECE Board Exam November 1996
Digital modulation technique used in modems.
ASK
PSK
FSK
All of these
ECE Board Exam November 1996
Which of the following is not a baseband signal modulation?
RF carrier
Video System
Audio signal
Binary coded pulses

1627.
ECE Board Exam November 1996
1628.
The standing wave ratio is equal to ________ if the load is properly matched with
the transmission line.
1629. 1
1630. 50
1631. 10
1632. 2
1633.
ECE Board Exam November 1996
1634.
Noise from random acoustic or electric noise that has equal per cycle over a
specified total frequency band.
1635. Thermal noise
1636. White noise
1637. Gaussian noise
1638. All of these
1639.
ECE Board Exam November 1996
1640.
When was the UHF channel (14-83) of television were added?
1641. 1852
1642. 1904
1643. 1947
1644. 1952
1645.
ECE Board Exam November 1996
1646.
Multiplexing in a time division multiplexer occurs based upon
1647. the position of a frame within the group of frames
1648. the positioning of data within a frame
1649. the priority assigned to a connected device
1650. the activity of a connected device
1651.
ECE Board Exam November 1996
1652.
Ethernet is baseband system using CSMA/CD operating at
1653. 20 Mbps
1654. 10 Mbps
1655. 30 Mbps
1656. 40 Mbps
1657.
ECE Board Exam November 1996
1658.
A microwave communications system space loss calculation formula is
1659. 92.4 + 10 log f +20 log d
1660. 94.2 + 10 log f +20 log d
1661. 92.4 + 20 log f +20 log d
1662. 94.2 + 20 log f +20 log d
1663.
ECE Board Exam November 1996
1664.
Which is the non-resonant antenna?
1665. Broadside Antenna
1666. Folded Dipole
1667. Rhombic antenna
1668. End fire array
1669.
ECE Board Exam November 1996
1670.
The first commercial satellite

1671. Explorer
1672. Sputnik
1673. Telstar
1674. Early bird
1675.
ECE Board Exam November 1996
1676.
A quadrature signaling have ________ possible states.
1677. 16
1678. 8
1679. 32
1680. 4
1681.
ECE Board Exam November 1996
1682.
Proposed the use of a clad glass fiber as a dielectric waveguide.
1683. Kao and Keck
1684. Karpon and Keck
1685. Karpon and Bockham
1686. Bockham and Kao
1687.
ECE Board Exam November 1996
1688.
What band does VSAT first operate?
1689. X-band
1690. C-band
1691. Ku-band
1692. L-band
1693.
ECE Board Exam November 1996
1694.
What is the method of diversity reception where the signal is transmitted on 2
different frequencies over the same path?
1695. Quadruple
1696. Frequency
1697. Polarization
1698. Space
1699.
ECE Board Exam November 1996
1700.
The wavelength of light has no role in
1701. Diffraction
1702. Interference
1703. Resolving power
1704. Polarization
1705.
ECE Board Exam November 1996
1706.
Which of the following filters block FM radio band for TV channels (2 to 13)?
1707. High-pass filter
1708. Band reject filter
1709. Low-pass filter
1710. Band-pass filter
1711.
ECE Board Exam November 1996
1712.
The standard ASCII
1713. is version II of ASC
1714. is used only in US and Canada
1715. has 132 characters including 32 control characters

1716. is subset of 8-bit EBCDIC code
1717.
ECE Board Exam November 1996
1718.
Luminous efficiency is least for a
1719. mercury vapor lamp
1720. low-wattage light bulb
1721. high-wattage light bulb
1722. fluorescent tube
1723.
ECE Board Exam November 1996
1724.
Transmission lines when connected to antenna have
1725. capacitive load
1726. resistive load whose resistance is less than characteristics impedance
1727. resistive load at the resonant frequency
1728. resistive load whose resistance is greater than the characteristic impedance of the
line
1729.
ECE Board Exam November 1996
1730.
What is the free space loss, in dB, between two microwave parabolic antennas
38.0 kilometer apart operating at 7.0 GHz?
1731. 145.6 dB
1732. 138.5 dB
1733. 135.5 dB
1734. 140.89 dB
1735.
ECE Board Exam November 1996
1736.
What is the equivalent output of a circuit in dBm, if it is has an output of 10
watts?
1737. 10 dBm
1738. 30 dBm
1739. 20 dBm
1740. 40 dBm
1741.
ECE Board Exam November 1996
1742.
Satellite engine use
1743. liquid fuel
1744. jet propulsion
1745. ion propulsion system
1746. solar jet
1747.
ECE Board Exam November 1996
1748.
Low-power radar uses
1749. RIMPATT
1750. TRAPATT
1751. Magnetron
1752. IMPATT
1753.
ECE Board Exam November 1996
1754.
Transmission line must be matched to the load to
1755. transfer maximum voltage to the load
1756. transfer maximum current to the load
1757. reduce the load current
1758. transfer maximum power to the load

1759.
ECE Board Exam November 1996
1760.
Electromagnetic wave travel at __________ in free space.
1761. 300,000 km/sec
1762. 100,000 km/ sec
1763. 400,000 km/sec
1764. 200km/sec
1765.
ECE Board Exam November 1996
1766.
When electromagnetic wave are propagated through a waveguide, they
1767. are reflected from the walls but do not travel along them
1768. travel along all four walls of the waveguide
1769. travel along the broader walls of the guide
1770. travel through the dielectric without touching the walls
1771.
ECE Board Exam November 1996
1772.
Codes must be
1773. agreed upon in advance between sender and receiver
1774. eight bit per character
1775. the same in all modern computer
1776. either seven or eighth bits per character
1777.
ECE Board Exam November 1996
1778.
Combination of modulator, channel and detector.
1779. Transceiver
1780. Discrete channel
1781. T/R channel
1782. Transponder
1783.
ECE Board Exam November 1996
1784.
What is the stage of the sand becoming silicon?
1785. Hot
1786. Gas
1787. Liquid
1788. Molten
1789.
ECE Board Exam November 1996
1790.
Noise reduction system used for film sound in movie
1791. dBx
1792. dolby
1793. dBa
1794. dBm
1795.
ECE Board Exam November 1996
1796.
What is the principal difference between asynchronous and synchronous
transmission?
1797. The clocking is mixed with the data in synchronous transmission
1798. The pulse height are difficult
1799. The clocking is derived from the data in synchronous
1800. The bandwidth required is difficult.
1801.
ECE Board Exam November 1996
1802.
You are measuring a voice channel at a -4 dB test point level, the meter reads -73
dBm (pure test tone) convert the reading in dBmCO.

1803. 16
1804. 18
1805. 22
1806. 12
1807.
ECE Board Exam November 1996
1808.
What is the type of emission use by standard AM radio broadcast?
1809. A0
1810. F3
1811. A3
1812. A5C
1813.
ECE Board Exam November 1996
1814.
____________ is the average rate of transmission of sound energy in a given
direction through a cross sectional area of 1 sq.m. at right angle to the direction.
1815. Sound pressure
1816. Sound intensity
1817. Pressure variation
1818. Loudness
1819.
ECE Board Exam November 1996
1820.
Top loading is used in an antenna in order to increase its ___________.
1821. input capacitance
1822. beamwidth
1823. bandwidth
1824. effective height
1825.
ECE Board Exam November 1996
1826.
What component in the telephone set has the primary function of interfacing the
handset to the local loop?
1827. Varistor
1828. Induction coil
1829. Resistor
1830. Capacitor
1831.
ECE Board Exam November 1996
1832.
The first passive satellite transponder.
1833. Early bird
1834. Score
1835. Moon
1836. Sputnik
1837.
ECE Board Exam November 1996
1838.
The primary purpose of the data modem is to
1839. interface analog terminal equipment to analog communications channel
1840. interface digital terminal equipment to analog communications channel
1841. interface analog terminal equipment to digital communications channel
1842. interface digital terminal equipment to digital communications channel
1843.
ECE Board Exam November 1996
1844.
____________ is the out-of-band signaling between toll central offices (Bell
System Standard)
1845. 2,000 Hz

1846.
1847.
1848.
1849.
1850.
1851.
1852.
1853.
1854.
1855.
1856.
1857.
1858.
1859.
1860.
1861.
1862.
1863.
1864.
1865.
1866.
1867.
1868.
1869.
1870.
1871.
1872.
1873.
1874.
1875.
1876.
1877.
1878.
1879.
1880.
1881.
1882.
1883.
1884.
1885.
1886.
1887.
1888.
1889.
1890.
1891.

800 Hz
3,835 Hz
3700 Hz
ECE Board Exam November 1996
Which symbol indicates that only one sideband is transmitted?
A3E
B8E
C3F
H3E
ECE Board Exam November 1996
A voice-grade circuit using the PTN has an ideal passband of
0 to 4 Hz
0 to 4 kHz
0 to 4 GHz
0 to 4 MHz
ECE Board Exam November 1996
1 micron is equal to ___________ meter(s).
10-6m
10-3 m
106 m
109 m
ECE Board Exam November 1996
The lowest resistance grounding on earth
Sand
Clay
Surface loam soil
Limestone
ECE Board Exam November 1996
Troposheric scatter uses the frequencies in the ________ band.
VLF
UHF
VHF
UF
ECE Board Exam November 1996
The unit of pitch
Decibel
Phon
Mel
Sone
ECE Board Exam November 1996
What kind of receiver is used in converntional telephone handset?
Capacitor
Carbon
Electromagnetic
Ceramic
ECE Board Exam November 1996

1892.
Basic speed rate of digital system.
1893. 144 kbps
1894. 1,544 kbps
1895. 64 kbps
1896. 2,048 kbps
1897.
ECE Board Exam November 1996
1898.
A horizontal antenna is
1899. centrally polarized
1900. vertically polarized
1901. horizontally polarized
1902. perpendicularly polarized
1903.
ECE Board Exam November 1996
1904.
What is the diameter of a copper wire to be used in a 16 km loop with a dc loop
resistance of 100 ohms/km?
1905. 0.108 cm
1906. 1.082 cm
1907. 0.017 cm
1908. 0.0465 cm
1909.
ECE Board Exam November 1996
1910.
If a fiber optic system has a rise time of 16 ns, the source rise time is 1.5 ns and
the detector rise time is 2 ns, what is the cable rise time?
1911. 14 ns
1912. 6 ns
1913. 9 ns
1914. 12.5 ns
1915.
ECE Board Exam November 1996
1916.
What is the phase delay of an 800 Hz voice signal if the phase shift is 15 degrees?
1917. 1.25 µsec
1918. 52 µsec
1919. 83.33 µsec
1920. 26 µsec
1921.
ECE Board Exam November 1996
1922.
What is the power loss of a telephone hybrid?
1923. 6 dB
1924. 2 dB
1925. 3 dB
1926. 1 dB
1927.
ECE Board Exam November 1996
1928.
You are measuring noise in a voice channel at 7 dB test point level. The meter
reads -56 dBm (FIA weighted). What is the reading in dBrnc?
1929. 20
1930. 32
1931. 35
1932. 25
1933.
ECE Board Exam November 1996
1934.
Space diversity transmission means transmitting and receiving on

1935. two or more antennas operating on two different frequencies
1936. two or more identical frequencies
1937. two or more different frequencies
1938. two or more antennas operating on the same frequencies
1939.
ECE Board Exam November 1996
1940.
Rules governing the transmission of digital information.
1941. Line protocol
1942. Isochronous
1943. Data communications
1944. Digital communications
1945.
ECE Board Exam November 1996
1946.
A digital identification associated with a cellular system
1947. SAT
1948. ESN
1949. MIN
1950. SIM
1951.
ECE Board Exam November 1996
1952.
____________ is measuring the propagated field strength over the projected
service area
1953. Radio sounding
1954. None of these
1955. Radio monitoring
1956. Radio survey
1957.
1958.
1959.
1960.
1961.
1962.
1963.
1964.
1965.

Test Yourself – Exam 03
ECE Board Exam April 1997

1966.
What is the impedance of a balance 4-wire with a diameter of 0.25 cm and spaced
2.5 cm apart using an insulator with a dielectric constant of 2.56?
1967.
1968.
A. 100Ω
1969.
B. 65Ω
1970.
C. 75 Ω
1971.
D. 50 Ω
1972.
1973.
ECE Board Exam April 1997
1974.
What is the impedance in ohms of a transformer marked for 25V, 4W, when the
secondary is correctly loaded?
1975.
150 Ω

1976.
1977.
1978.
1979.
1980.
1981.

156 Ω
160 Ω
165 Ω

1982.
1983.
1984.
1985.
1986.

A single conductor running from the transmitter to the antenna.
RG-8/U
Single line wire
Twin-lead
MIcrostrip

1987.
1988.

ECE Board Exam April 1997

ECE Board Exam April 1997

1989.
If voltage change equal to twice its original value, what is its corresponding
change in dB?
1990.
9 dB
1991.
6dB
1992.
10 dB
1993.
3dB
1994.
1995.

ECE Board Exam April 1997

1996.
1997.
1998.
1999.
2000.

To couple a coaxial line to parallel line, it is better to use a ______.
Slotted line
Quarter-wave transformer
Directional Coupler
Balun

2001.
2002.

ECE Board Exam April 1997

2003.
What is the characteristic impedance of a single wire with a diameter d= 0.25 mm
placed at the center between grounded parallel planes separated by 1 mm apart. The wire is
held by a material with a velocity factor of 0.75.
2004.
85 Ω
2005.
63 Ω
2006.
50 Ω
2007.
75 Ω
2008.
2009.

ECE Board Exam April 1997

2010.
If you have available number of power amplifiers with a gain of 100 each, how
many such amplifiers do you need to cascade to give an overall gain of 60 dB?
2011.
3

2012.
2013.
2014.

4
5
2

2015.
2016.

ECE Board Exam April 1997

2017.
level.
2018.
2019.
2020.
2021.

________ sets a limit on the maximum capacity of a channel with a give noise
Hartley theorem
Shannon-Hartley theorem
Nyquist theorem
Shannon theorem

2022.
2023.

ECE Board Exam April 1997

2024.
2025.
2026.
2027.
2028.

Transmission sent in both directions simultaneously.
Full duplex
Duplex
Half duplex
Simplex

2029.
2030.

ECE Board Exam April 1997

2031.
2032.
2033.
2034.
2035.

Industrial noise frequency is between _________.
200 to 3000 Mhz
15 to 160 Mhz
0 to 10 Khz
20 Ghz

2036.
2037.

ECE Board Exam April 1997

2038.
2039.
2040.
2041.
2042.

Reference noise temperature.
70 deg F
30 deg C
290 Kelvin
25 deg C

2043.
2044.

ECE Board Exam April 1997

2045.
2046.
2047.
2048.
2049.

What is the reference frequency of CCITT psophometric noise measurement?
800 Hz
1500 Hz
3400 Hz
1000 Hz

2050.
2051.

ECE Board Exam April 1997

2052.
2053.
2054.
2055.
2056.

Which does not effect noise in a channel?
None of these
Bandwidth
Temperature
Quantizing level

2057.
2058.

ECE Board Exam April 1997

2059.
The random and unpredictable electric signal from natural causes, both internal
and external to the system is know as ________.
2060.
Distortion
2061.
Noise
2062.
Attenuation
2063.
Interference
2064.
2065.
2066.
2067.
2068.
2069.
2070.
2071.
2072.

ECE Board Exam April 1997
The most common unit of noise measurement in white noise testing.
dBw
dBk
dBm
NPR

2073.
2074.

ECE Board Exam April 1997

2075.
2076.
2077.
2078.
2079.

Unit of noise power of psophometer
dBa
pWp
dBm
dBmO

2080.
2081.

ECE Board Exam April 1997

2082.
2083.
2084.
2085.
2086.

100% modulation in AM means a corresponding increase in total power by:
25%
75%
100%
50%

2087.
2088.

ECE Board Exam April 1997

2089.
If the modulation index of an AM wave is doubled, the antenna current is also
doubled, the AM system being used is
2090.
A5C
2091.
A3J
2092.
A3H
2093.
A3
2094.
2095.

ECE Board Exam April 1997

2096.
2097.
2098.
2099.
2100.

What particular circuit that rids FM of noise?
HPF
Phase shifter
Limiter
LPF

2101.
2102.

ECE Board Exam April 1997

2103.
2104.
2105.
2106.
2107.

What is the advantage of PTM over PAM?
All of these
Low sampling rate is required
Much better noise immunity
Simpler to generate

2108.
2109.

ECE Board Exam April 1997

2110.
At 100% modulation, the sum fo the effective voltages in both sidebands is equal
to ______% of the unmodulated carrier voltage.
2111.
50
2112.
71
2113.
100
2114.
25
2115.
2116.

ECE Board Exam April 1997

2117.
2118.
2119.
2120.
2121.

A carrier signal has ______.
Constant peak amplitude
The information
Frequency range 20-20000 Hz
A varying amplitude

2122.
2123.

ECE Board Exam April 1997

2124.
2125.

Which transmit only one sideband?
A3E

2126.
2127.
2128.

3AJ
11BE
H3E

2129.
2130.

ECE Board Exam April 1997

2131.
2132.
2133.
2134.
2135.

The final amplifier of either FM or AM transmitter operates as
Class B
Class C
Class A
Class D

2136.
2137.

ECE Board Exam April 1997

2138.
Modulation means
2139.
Varying of information
2140.
Utilization of a single transmission channel to carry multiple signals
2141.
Varying of some parameters of a carrier such as its amplitude to transmit
information
2142.
Transmit pulses in DC form on a copper wire
2143.
2144.

ECE Board Exam April 1997

2145.
2146.
2147.
2148.
2149.

What is the advantage of sidetone?
High transmission efficiency
Results to a strengthened signal
No energy dissipation
Assures that the telephone is working

2150.
2151.

ECE Board Exam April 1997

2152.
2153.
2154.
2155.
2156.

The standard test tone
0dB
10 dBm
0 dBm
10 dB

2157.
2158.

ECE Board Exam April 1997

2159.
2160.
2161.
2162.
2163.

One (1) Erlang is equal to ________.
360 CCS
100 CCS
36 CCS
3.6 CCS

2164.
2165.

ECE Board Exam April 1997

2166.
2167.
2168.
2169.
2170.

Transmission of printed material over telephone lines.
Video text
Facsimile
Encoding
Xerox copy

2171.
2172.

ECE Board Exam April 1997

2173.
2174.
2175.
2176.
2177.

1-CCS is equal to?
60
100
600
1

2178.
2179.

ECE Board Exam April 1997

2180.
2181.
2182.
2183.
2184.

1 Erlang is ______.
1000 TU
10 TU
100TU
1 TU

2185.
2186.

ECE Board Exam April 1997

2187.
2188.
2189.
2190.
2191.

When waves bend away from straight lines of travel, it is called _________.
Refraction
Reflection
Rarefaction
Diffraction

2192.
2193.

ECE Board Exam April 1997

2194.
Highest frequency that can be used for skywave HF communications between two
given points on earth.
2195.
Gyro frequency
2196.
Maximum usable frequency
2197.
Critical frequency
2198.
Virtual frequency
2199.
2200.

ECE Board Exam April 1997

2201.
2202.
2203.
2204.
2205.

Electromagnetic radiation theory was profounded by ______.
Sir Edward Appleton
Sir Isaac Newton
James Clerk Maxwell
Michael Faraday

2206.
2207.

ECE Board Exam April 1997

2208.
Type of transmission path that permits communication in the frequency range
from 30 to 60 MHz and over distances form about 1000 to 2000 km.
2209.
Ducting
2210.
Ionospheric scatter
2211.
Microwave
2212.
Troposcatter
2213.
2214.

ECE Board Exam April 1997

2215.
2216.
2217.
2218.
2219.

What is the thickest layer of the ionosphere?
E
F1
F2
D

2220.
2221.

ECE Board Exam April 1997

2222.
2223.
2224.
2225.
2226.

Distance traveled by a wave in the time of one cycle.
Hop
Frequency
Wavelength
Crest

2227.
2228.

ECE Board Exam April 1997

2229.
Which region of the ionosphere is mainly responsible for long distance night time
communication?
2230.
A layer
2231.
D layer
2232.
E layer
2233.
F layer
2234.
2235.

ECE Board Exam April 1997

2236.
2237.

What is the effective earth’s radius when N=300?
8500 km

2238.
2239.
2240.

6370 km
7270 km
7950 km

2241.
2242.

ECE Board Exam April 1997

2243.
2244.
2245.
2246.
2247.

The polarization of a discone antenna is _____.
Horizontal
Vertical
Omni
Directional

2248.
2249.

ECE Board Exam April 1997

2250.
2251.
2252.
2253.
2254.

_______ is the horizontal pointing angle of an antenna.
Right angle
Angle of elevation
Bandwidth
Azimuth

2255.
2256.

ECE Board Exam April 1997

2257.
2258.
2259.
2260.
2261.

Which is properly terminated antenna?
Rhombic
Hertz
Marconi
Dipole

2262.
2263.

ECE Board Exam April 1997

2264.
______ is a device that detects both vertically and horizontally polarized signals
simultaneously.
2265.
Crystal
2266.
Orthomode transducer
2267.
Light transducer
2268.
Optoisolator
2269.
2270.

ECE Board Exam April 1997

2271.
How much does the radiated power of an antenna increases if its current increased
by 3.3 times?
2272.
6.6 times
2273.
3.3 times
2274.
10.89 times

2275.

9.9 times

2276.
2277.

ECE Board Exam April 1997

2278.
What do you call the energy that was not radiated into space or completely
transmitted?
2279.
Incident waves
2280.
Captured waves
2281.
Standing waves
2282.
Modulated waves
2283.
2284.
2285.
design?
2286.
2287.
2288.
2289.

ECE Board Exam April 1997
What is the estimated medium wind loading in the Philippines for antenna tower
200 kph
250 kph
300 kph
100 kph

2290.
2291.

ECE Board Exam April 1997

2292.
2293.
2294.
2295.
2296.

The minimum number of turns a helix antenna must have.
4
5
3
6

2297.
2298.

ECE Board Exam April 1997

2299.
When testing transmitter to prevent interfering with other stations, which type of
antenna must be used?
2300.
Dummy antenna
2301.
Hertzian antenna
2302.
None of these
2303.
Void antenna
2304.
2305.
2306.
radation.
2307.
2308.
2309.

ECE Board Exam April 1997
A device that radiates electromagnetic energy and or intercepts electromagnetic
Antenna
Transmitter
Transmission line

2310.

Transceiver

2311.
2312.

ECE Board Exam April 1997

2313.
2314.
2315.
2316.
2317.

The frequency of operation of a dipole antenna cut to length of 3.4 m.
42.9 MHz
61.3 MHz
38.5 MHz
53.5 MHz

2318.
2319.

ECE Board Exam April 1997

2320.
2321.
2322.
2323.
2324.

Full duplex transmission means
One way transmission
24-hour transmission
Broadcast transmission
Two-way simultaneous transmission

2325.
2326.

ECE Board Exam April 1997

2327.
2328.
2329.
2330.
2331.

Transmission system for a multidrop network
Taken passing
Polling
Switching
CSMA/CD

2332.
2333.

ECE Board Exam April 1997

2334.
2335.
2336.
2337.
2338.

Synchronous modems cost more than asynchronous modem because _______.
They have larger bandwidth
They are larger
The production volume is larger
They have clock recovery circuits

2339.
2340.

ECE Board Exam April 1997

2341.
2342.
2343.
2344.
2345.

What equation defines the composition of an ISDN basic access line?
B+2D
B+D
2B+2D
2B+D

2346.
2347.

ECE Board Exam April 1997

2348.
2349.
2350.
2351.
2352.

Modem is referred to as ______.
Universal asynchronous Rx/Tx
Data communication equipment
Universal synchronous Rx/Tx
Data terminal equipment

2353.
2354.

ECE Board Exam April 1997

2355.
2356.
2357.
2358.
2359.

_______ character signifies the start of the test for Bisync.
STX
ETX
SOH
BCC

2360.
2361.

ECE Board Exam April 1997

2362.
2363.
2364.
2365.
2366.

What is the reason why companding is employed in PCM systems?
To overcome impulse noise in PCM receivers
To allow amplitude limiting in the receivers
To solve quantizing noise problem
To protect small signals in PCM from quantizing distortion

2367.
2368.

ECE Board Exam April 1997

2369.
2370.
2371.
2372.
2373.

What is framing?
Is concerned of synchronous system
Refers to parallel transmission
Is concerned with the boundaries between characters
Is concerned with individual bits

2374.
2375.

ECE Board Exam April 1997

2376.
2377.
2378.
2379.
2380.

The method of determining the bandwidth of any processing system is ______.
Bandwidth analysis
Frequency spectrum
Spectral analysis
Frequency analysis

2381.
2382.

ECE Board Exam April 1997

2383.
2384.
2385.
2386.

It is a protocol used to connect the other packet witching network.
X.25
X.50
X.10

2387.

X.75

2388.
2389.

ECE Board Exam April 1997

2390.
2391.
2392.
2393.
2394.

Slowest communications hardware product.
Synchronous
Asynchronous
Ethernet
Internet

2395.
2396.

ECE Board Exam April 1997

2397.
aliasing.
2398.
2399.
2400.
2401.

Highest theoretical frequency that can be processed at a sampling rate without
Folding frequency
Resonant frequency
Natural frequency
Critical frequency

2402.
2403.

ECE Board Exam April 1997

2404.
2405.
2406.
2407.
2408.

Data is directly on the transmission cable.
Asynchronous
Synchronous
Baseband
Broadband

2409.
2410.

ECE Board Exam April 1997

2411.
A source code whose average word length approaches the fundamental limit set
by the entropy of a discrete memoryless source.
2412.
Prefix code
2413.
Huffman code
2414.
Entropy code
2415.
Source code
2416.
2417.
2418.
level.
2419.
2420.
2421.
2422.

ECE Board Exam April 1997
______ sets the limit on the maximum capacity of a channel with a given noise
Hartley theorem
Shannon-hartley theorem
Nyquist theorem
Shannon theorem

2423.
2424.

ECE Board Exam April 1997

2425.
2426.
2427.
2428.
2429.

Gateway can interconnect LANs that have ____ protocols and formats.
The same
Different or the same
Totally different
None of these

2430.
2431.

ECE Board Exam April 1997

2432.
2433.
2434.
2435.
2436.

Steps to follow to produce PCM signal.
Quantizing, sampling, and coding
Sampling, quantizing, and coding
Sampling, coding and quantizing
Coding, quantizing and coding

2437.
2438.

ECE Board Exam April 1997

2439.
2440.
2441.
2442.
2443.

Transmission sent in both directions simultaneously.
Full duplex
Duplex
Half duplex
Simplex

2444.
2445.

ECE Board Exam April 1997

2446.
_______ detects the satellite signal relayed from the feed and converts it to an
electric current, amplifies and lower its frequency.
2447.
Feedhorn
2448.
Satellite dish
2449.
Satellite receiver
2450.
LNB
2451.
2452.

ECE Board Exam April 1997

2453.
2454.
2455.
2456.
2457.

What kind of battery panels are used in some advance satellites?
Gallium Arsenide solar panel
Germanium based panels
Silicon based panels
Gallium Phosphate solar panel

2458.
2459.

ECE Board Exam April 1997

2460.
2461.
2462.
2463.
2464.

Footprint refers to coverage area in the globe
Satellite radiation polarization
Satellite navigation
Satellite radiation pattern
Satellite coverage

2465.
2466.

ECE Board Exam April 1997

2467.
2468.
2469.
2470.
2471.

Asia Sat I covers how many countries in Asia?
38
40
44
42

2472.
2473.

ECE Board Exam April 1997

2474.
2475.
2476.
2477.
2478.

Insertion loss of connector-type splices for a single-mode fiber cable.
0.2 dB
0.3 dB
0.09 dB
0.38 dB

2479.
2480.

ECE Board Exam April 1997

2481.
2482.
2483.
2484.
2485.

A non-coherent light source for optical communications system.
PIN Diode
ILD
APD
LED

2486.
2487.

ECE Board Exam April 1997

2488.
2489.
2490.
2491.
2492.

Type of fiber that has the highest modal dispersion
Step-index multimode
Step-index single mode
Graded index mode
Graded index multimode

2493.
2494.

ECE Board Exam April 1997

2495.
2496.
2497.
2498.

Fiber optic cable operates near _______ frequencies.
800 THz
20 MHz
200 MHz

2499.

2 GHz

2500.
2501.

ECE Board Exam April 1997

2502.
2503.
2504.
2505.
2506.

Lifetime of ILD’s
150,000 h
100,000 h
50,000 h
200,000 h

2507.
2508.

ECE Board Exam April 1997

2509.
time.
2510.
2511.
2512.
2513.
2514.
2515.

The sound energy per unit area at right angles to the propagation direction per unit
Sound intensity
Loudness
Coherence
Sound stress
ECE Board Exam April 1997

2516.
_______ is the transmission of sound from one room to an adjacent room thru
common walls, floors or ceilings.
2517.
Reverberation
2518.
Refraction
2519.
Flanking transmission
2520.
Reflection
2521.
2522.

ECE Board Exam April 1997

2523.
The sound power level of a jet plane flying at a height of 1 km is 160 dB. What is
the maximum sound pressure level on the ground directly below the plane assuming that the
aircraft radiates sound equally in all directions?
2524.
59.1 dB
2525.
69.1 dB
2526.
79.1 dB
2527.
89.1 dB
2528.
2529.

ECE Board Exam April 1997

2530.
2531.
2532.
2533.

Lowest frequency produced by a musical instrument.
Fundamental
Midrange
Period

2534.

Harmonic

2535.
2536.

ECE Board Exam April 1997

2537.
2538.
2539.
2540.
2541.

Sound intensity level is ________.
10 log I/I(ref)
10 log I(ref)/I
30 log I/I(ref)
20 log I/I(ref)

2542.
2543.

ECE Board Exam April 1997

2544.
2545.
2546.
2547.
2548.

Tendency of sound energy to spread.
Reflection
Diffraction
Rarefaction
Refraction

2549.
2550.

ECE Board Exam April 1997

2551.
2552.
2553.
2554.
2555.

______ used to measure speech volume
Volume meter
Audio frequency meter
Volume unit meter
Speech meter

2556.
2557.

ECE Board Exam April 1997

2558.
What is the local oscillator frequency range commercial AM broadcast if it is
equal to 455 KHz.
2559.
540 to 1600 KHz
2560.
0 to 1600 KHz
2561.
995 to 2055 KHz
2562.
0 to 455 KHz
2563.
2564.

ECE Board Exam April 1997

2565.
2566.
2567.
2568.
2569.

TV channels 2, 4 and 5 are known as ________.
Mid band UHF
Low band UHF
High band VHF
Low band VHF

2570.

2571.

ECE Board Exam April 1997

2572.
2573.
2574.
2575.
2576.

______ is the first component of any MATV system to received broadcast signals.
Receiver
Antenna
Filter
Transmitter

2577.
2578.

ECE Board Exam April 1997

2579.
motion.
2580.
2581.
2582.
2583.

Mechanism or device which enables the TV camera to move in internal and tilting
Tilting
Scanner
Pan/tilt device
Panning device

2584.
2585.

ECE Board Exam April 1997

2586.
2587.
2588.
2589.
2590.

The allowable deviation ratio of commercial FM broadcast.
25
15
5
75

2591.
2592.

ECE Board Exam April 1997

2593.
2594.
2595.
2596.
2597.

______ is the time duration for one horizontal trace.
48µs
52 µs
62 µs
50 µs

2598.
2599.

ECE Board Exam April 1997

2600.
2601.
2602.
2603.
2604.

Which is atmospheric attenuation?
Attenuation due to rain
Attenuation due to other gasses
Attenuation due to mist and fog
Due to water vapor and oxygen

2605.
2606.

ECE Board Exam April 1997

2607.

A microwave system that requires the use of repeater.

2608.
2609.
2610.
2611.

Intervening terrain is favorable
Distances involved are greater
The required reliability is met
All of these

2612.
2613.

ECE Board Exam April 1997

2614.
2615.
2616.
2617.
2618.

What frequency does oxygen causes excessive attenuation
119 GHz
183 GHz
310 GHz
60 GHz

2619.
2620.

ECE Board Exam April 1997

2621.
2622.
2623.
2624.
2625.

RADAR means
Radio detection and rating
Radio detection and ranging
Radio distance and ranging
Radio delay and ranging

2626.
2627.

ECE Board Exam April 1997

2628.
2629.
2630.
2631.
2632.

A microwave link between the earth station and the down-town terminal.
STL
Uplink
Downlink
Terrestrial link

2633.
2634.

ECE Board Exam April 1997

2635.
2636.
2637.
2638.
2639.

The advantage of periscope antenna in microwave
Minimize interference to and from other neighboring stations
Shorten waveguide link
Reduce tower height
All of these

2640.
2641.

ECE Board Exam April 1997

2642.
2643.
2644.
2645.
2646.

Professional Regulations Commission was created under ______.
PD 323
PD 223
PD 232
RA 223

2647.
2648.

ECE Board Exam April 1997

2649.
The institutionalization of the continuing Professional Education (CPE) Program
of the various regulated profession under the supervision of the Professional Regulation
Commission.
2650.
E.O. No. 266
2651.
E.O. No. 626
2652.
E.O. No. 662
2653.
P.D. 381
2654.
2655.

ECE Board Exam April 1997

2656.
The basic law providing for the regulation of radio station, communications in the
Philippines and other purposes.
2657.
Act. No.`3846
2658.
D.O. No. 11
2659.
D.O. No. 88
2660.
D.O. No. 5
2661.
2662.

ECE Board Exam April 1997

2663.
Listing of the date and time events, programs , equipment, test, malfunctions and
corrections in communication system.
2664.
File
2665.
Documentation
2666.
Reporting
2667.
Log
2668.
2669.
2670.
2671.
2672.
2673.
2674.
2675.

Test Yourself – Exam 04
ECE Board Exam April 1997

2676.
2677.
2678.
2679.
2680.

Extra-terrestrial noise is observable at frequencies from
0 to 20 KHz
Above 2 GHz
8 to 1.43 GHz
5 to 8 GHz

2681.
2682.

ECE Board Exam April 1997

2683.
2684.
2685.
2686.
2687.

Band of light waves, that are too short to be seen by human eye.
Visible
Infrared
Ultraviolet
Amber

2688.
2689.

ECE Board Exam April 1997

2690.
2691.
2692.
2693.
2694.

Two wires that are bent 90 degrees apart.
Hertz
Dipole
Log-periodic
Rhomic

2695.
2696.

ECE Board Exam April 1997

2697.
2698.
2699.
2700.
2701.

The first symbol in the designation of radio emission under the ITU rules to
Nature of signals modulating the main carrier
Type of information to be transmitted
Bandwidth
Type of modulation of the main carrier

2702.
2703.

ECE Board Exam April 1997

2704.
Operating method in which the transmission is made alternately in each direction
of a telecommunication channel
2705.
Semi-duplex operation
2706.
Duplex operation
2707.
Half-duplex operation
2708.
Simplex operation
2709.
2710.

ECE Board Exam April 1997

2711.
2712.
2713.
2714.
2715.

Production of radiation by a radio transmitting station
Monitoring
Emission
Radiation
Transmission

2716.
2717.

ECE Board Exam April 1997

2718.
to
2719.

The third symbol in the designation of radio emission under the ITU rules refers
Type of the modulation of the main carrier

2720.
2721.
2722.

Bandwidth
Nature of the signals modulating the main carrier
Type of information to be transmitted

2723.
2724.

ECE Board Exam April 1997

2725.
A form of telecommunication for the transmission of transient images of fixed or
moving objects.
2726.
E-mail
2727.
Television
2728.
Radio
2729.
Internet
2730.
2731.

ECE Board Exam April 1997

2732.
2733.
2734.
2735.
2736.

Radiation pattern of a discone.
Unidirectional
Bidirectional
Omnidirectional
Figure of eight

2737.
2738.

ECE Board Exam April 1997

2739.
2740.
2741.
2742.
2743.

Another SEG function that allows a person to be superimposed on another scene.
Visual effect
Wiper
Chroma keying
Special effect generation

2744.
2745.

ECE Board Exam April 1997

2746.
2747.
2748.
2749.
2750.

What signal-to-noise ratio is required for satisfactory telephone services?
50 dB
30 dB
40dB
20 dB

2751.
2752.

ECE Board Exam April 1997

2753.
The use of telecommunication for automatic indicating or recording measurement
at the distance from the measuring instrument.
2754.
Monitoring
2755.
Tracking
2756.
Telemetry

2757.

Telecommand

2758.
2759.

ECE Board Exam April 1997

2760.
The standard deviation of the variation in the transmission loss of a circuit should
not exceed
2761.
3 dB
2762.
1 dB
2763.
5 dB
2764.
0.5dB
2765.
2766.

ECE Board Exam April 1997

2767.
2768.
2769.
2770.
2771.

Noise caused by the thermal agitation of electrons in resistance.
All of these
Thermal noise
Johnson’s noise
White noise

2772.
2773.

ECE Board Exam April 1997

2774.
2775.
2776.
2777.
2778.

Unity gain antenna
Isotropic
Rhombic
Half-wave dipole
Dummy

2779.
2780.

ECE Board Exam April 1997

2781.
The series of periodically recurrent pulses is modulated in amplitude by the
corresponding instantaneous samples.
2782.
PFM
2783.
PWM
2784.
PDM
2785.
PAM
2786.
2787.

ECE Board Exam April 1997

2788.
This type of transmission permits communication in the frequency range from 30
to 60 MHz and over distances from about 1000 to 2000 km.
2789.
Troposcatter
2790.
Ionospheric scatter
2791.
Ducting
2792.
Microwave

2793.
2794.

ECE Board Exam April 1997

2795.
2796.
2797.
2798.
2799.

A region in front of a paraboloid antenna.
Transmission zone
All of these
Fraunhofer
Fresnel

2800.
2801.

ECE Board Exam April 1997

2802.
2803.
2804.
2805.
2806.

Designates the sensation of low or high in the sense of the base and treble.
Frequency
Intensity
Pitch
SPL

2807.
2808.

ECE Board Exam April 1997

2809.
stations.
2810.
2811.
2812.
2813.
2814.
2815.

A good example of a pilot tone system used in commercial frequency modulation
FDM
Time division
Stereo multiplexing
Frequency modulation
ECE Board Exam April 1997

2816.
Emission on a frequency or frequencies immediately outside the necessary
bandwidth which result from the modulation process except spurious emission.
2817.
Radiation
2818.
Noise
2819.
Out of the band
2820.
Interference
2821.
2822.

ECE Board Exam April 1997

2823.
2824.
2825.
2826.
2827.

A helical antenna is used for satellite tracking because of ______.
Broad bandwidth
Good front-to-back
Maneuverability
Circular polarization

2828.
2829.

ECE Board Exam April 1997

2830.
2831.
2832.
2833.
2834.

Background noise is the same as the following except
Impulse noise
White noise
Thermal noise
Gaussian noise

2835.
2836.

ECE Board Exam April 1997

2837.
2838.
2839.
2840.
2841.

Electronic equipment used to measure standing wave ration.
Reflectometer
Wavemeter
Altimeter
Multimeter

2842.
2843.

ECE Board Exam April 1997

2844.
A single sideband emission in which the degree of carrier suppression enables the
carrier to be reconstituted and to be used for demodulation.
2845.
Reduce carrier single sideband emission
2846.
Half carrier single sideband emission
2847.
Full carrier single sideband emission
2848.
Standard single sideband emission
2849.
2850.

ECE Board Exam April 1997

2851.
2852.
2853.
2854.
2855.

Station in the mobile service not intended to be used while in motion.
Coast station
Fixed station
Base station
Land station

2856.
2857.

ECE Board Exam April 1997

2858.
2859.
2860.
2861.
2862.

The electric field lines in a plane perpendicular to the earth’s surface.
Elliptical polarization
Circular polarization
Horizontal polarization
Vertical polarization

2863.
2864.

ECE Board Exam April 1997

2865.
2866.
2867.

Known to be the first satellite capable to receive and transmit simultaneously.
Score
Syncom I

2868.
2869.

Telstar 1
Echo1

2870.
2871.

ECE Board Exam April 1997

2872.
2873.
2874.
2875.
2876.

A digital carrier facility used to transmit a DSI-formatted signal at 1.544. Mbps.
T2
T1
T4
T3

2877.
2878.

ECE Board Exam April 1997

2879.
12 voice channels are sampled at 8000 sampling rate and encoded into 8 bit PCM
word. Determine the rate of the data stream.
2880.
354 kbps
2881.
750 kbps
2882.
768 kbps
2883.
640 kbps
2884.
2885.
2886.
system.
2887.
2888.
2889.
2890.
2891.
2892.

ECE Board Exam April 1997
The most common device used as a light detector in fiber optic communications
LED
Darlington phototransistor
APDs
PIN diode
ECE Board Exam April 1997

2893.
Two resistors, 20kΩ, and 50kΩ are at ambient temperature. Calculate for a
bandwidth equal to 100kHz, the thermal noise voltage for the two resistors connected in
parallel.
2894.
0.4782µV
2895.
4278 µV
2896.
4.78 µV
2897.
47.8 µV
2898.
2899.

ECE Board Exam April 1997

2900.
2901.
2902.

Calculate the energy of the photon of infrared light energy at 1.55µm
1.28x10-19 J
1.6 x10-19 J

2903.
2904.

1.22 x10-16 J
1.9 x10-14 J

2905.
2906.

ECE Board Exam April 1997

2907.
If a fiber optic system has a rise time of 38.55 ns, the source rise time is 12 ns and
the detector rise time is 12 ns, what is the cable rise time?
2908.
34.61 ns
2909.
14.55 ns
2910.
52.55 ns
2911.
26.25 ns
2912.
2913.

ECE Board Exam April 1997

2914.
2915.
2916.
2917.
2918.

Nominal voice channel
20 to 20 KHz
16 to 16 KHz
3 to 3 KHz
4 KHz

2919.
2920.

ECE Board Exam April 1997

2921.
2922.
2923.
2924.
2925.

Two or more antennas separated by 9 wavelengths are used.
Hybrid diversity
Space diversity
Polarized diversity
Frequency diversity

2926.
2927.

ECE Board Exam April 1997

2928.
2929.
2930.
2931.
2932.

Nif stands for
Narrow intermediate frequency
Noise interference figure
Noise improvement factor
Non-intrinsic fugure

2933.
2934.

ECE Board Exam April 1997

2935.
Any small element of space in the path of a wave may be considered as a source
of secondary wavelet.
2936.
De Morgan’s Principle
2937.
Faraday’s Law
2938.
Huygen’s Principle
2939.
Fresnel’s Law of optics

2940.
2941.

ECE Board Exam April 1997

2942.
2943.
2944.
2945.
2946.

Modulation in which the modulated wave is always present.
Carrier modulation
Front-end
Continuous modulation
Log-periodic modulation

2947.
2948.

ECE Board Exam April 1997

2949.
2950.
2951.
2952.
2953.

Atmospheric noise is less at severe frequencies above
Audio level
30 MHz
10 GHz
1 GHz

2954.
2955.

ECE Board Exam April 1997

2956.
2957.
2958.
2959.
2960.

At height about 180 km above the earth exist only during daylight.
F2 layer
D layer
E layer
F1 layer

2961.
2962.

ECE Board Exam April 1997

2963.
2964.
2965.
2966.
2967.

Radiation characteristics of a dipole
Figure of eight
Omnidirectional
Bidirectional
Unidirectional

2968.
2969.

ECE Board Exam April 1997

2970.
2971.
2972.
2973.
2974.

Determine the gain of a 6 ft. parabolic dish operating at 1800 MHz.
30 dB
11.2 dB
15.5 dB
28.17 dB

2975.
2976.

ECE Board Exam April 1997

2977.

An electromagnetic wave is ________ polarized when the electric field lies

wholly in one plane containing the direction of propagation.
2978.
Horizontally
2979.
Linearly
2980.
Circularly
2981.
Vertically
2982.
2983.

ECE Board Exam April 1997

2984.
2985.
2986.
2987.
2988.

A device that reduces the intensity of light in fiber optics communication systems.
Reducer
Quality factor
Optical attenuator
Compressor

2989.
2990.

ECE Board Exam April 1997

2991.
2992.
2993.
2994.
2995.

Propagation mode of microwave in a waveguide is known as _______.
TM
TE
SW
TEM

2996.
2997.

ECE Board Exam April 1997

2998.
The width of the frequency band which is just sufficient to ensure the
transmission of information at the rate and with the quality required under a specified
condition and class of emission.
2999.
Occupied bandwidth
3000.
Reference frequency
3001.
Necessary bandwidth
3002.
Frequency tolerance bandwidth
3003.
3004.

ECE Board Exam April 1997

3005.
3006.
3007.
3008.
3009.

A convenient method of determining antenna impedance.
Stub matching
Reactance circle
Smith chart
Trial and error

3010.
3011.

ECE Board Exam April 1997

3012.
3013.

Which of the following fall under the high frequency band of the radio spectrum?
8.2345 MHz

3014.
3015.
3016.

150.50 MHz
2.4555 MHz
35.535 MHz

3017.
3018.

ECE Board Exam April 1997

3019.
3020.
3021.
3022.
3023.

The electric field lies in a plane parallel to the earth’s surface.
Elliptical polarization
Horizontal polarization
Vertical polarization
Circular polarization

3024.
3025.

ECE Board Exam April 1997

3026.
The use of telecommunication for the transmission of signals to initiate, modify or
terminate functions of equipment at a distance.
3027.
Tracking
3028.
Telemetry
3029.
Telecommand
3030.
Space telemetry
3031.
3032.

ECE Board Exam April 1997

3033.
The product of the power supplied to the antenna and its gain relative to a halfwave dipole in a given direction.
3034.
Peak envelope power
3035.
ERP
3036.
Rated power
3037.
Carrier power’
3038.
3039.

ECE Board Exam April 1997

3040.
3041.
3042.
3043.
3044.

The Ku-band in the satellite service
14/11 GHz
30/17 GHz
8/7 GHz
6/4 GHz

3045.
3046.

ECE Board Exam April 1997

3047.
The sinusoidal carrier is pulsed so that one of the binary states is represented by a
carrier while the other is represented by its absence.
3048.
FSK
3049.
ASK

3050.
3051.

PSK
QAM

3052.
3053.

ECE Board Exam April 1997

3054.
Width measured in degrees of a major lobes between end of the love at which the
relative power is one half (-3dB) its value from the peak of the lobe.
3055.
Bandwidth
3056.
Wavelength
3057.
Radiation
3058.
Beamwidth
3059.
3060.

ECE Board Exam April 1997

3061.
3062.
3063.
3064.
3065.

The most common unit of noise measurement in white noise voltage testing.
NPR
dBm
dBW
dBrn

3066.
3067.

ECE Board Exam April 1997

3068.
Any governmental office responsible in discharging the obligations undertaken in
the convention of the ITU and the regulation.
3069.
Administration
3070.
The union
3071.
Country
3072.
Telecommunications office
3073.
3074.

ECE Board Exam April 1997

3075.
3076.
3077.
3078.
3079.

A large speaker having a large diameter (15 cm and above)
Coaxial speaker
Woofer
Tweeter
Trixial speaker

3080.
3081.

ECE Board Exam April 1997

3082.
3083.
3084.
3085.
3086.

Coaxial lines are used on those systems operating _______.
Below 2 GHz
At 300 MHz
Above 10KHz
Above 10GHz

3087.
3088.

ECE Board Exam April 1997

3089.
3090.
3091.
3092.
3093.

Determine the dynamic range for a 10 bit sign magnitude code.
1023
425
511
756

3094.
3095.

ECE Board Exam April 1997

3096.
A coherent binary phase shift keyed BPSK transmitter operates at a bit rate of 20
Mbps with a carrier to noise ratio C/N of 8.8dB. Find Eb/No.
3097.
73 dB
3098.
62.4 dB
3099.
81.8 dB
3100.
8.8 dB
3101.
3102.

ECE Board Exam April 1997

3103.
3104.
3105.
3106.
3107.

Receives and collects satellite signals form a broadcast satellite.
LNB
Yagi-Uda array
Satellite receiver
Satellite disk

3108.
3109.

ECE Board Exam April 1997

3110.
What is the effect in over modulated amplitude modulated radio broadcasting
transmission?
3111.
Interference to adjacent channel
3112.
Higher fidelity
3113.
Increase noise
3114.
Higher audio signal
3115.
3116.

ECE Board Exam April 1997

3117.
Average power of a radio transmitter supplied to the antenna transmission line by
a transmitter during one radio frequency cycle taken under the condition of no modulation.
3118.
Peak envelop power
3119.
Rated power
3120.
Carrier power
3121.
Mean power
3122.

3123.

ECE Board Exam April 1997

3124.
speech.
3125.
3126.
3127.
3128.

A method of expressing the amplitude of complex non-periodic signals such as

3129.
3130.

Frequency
Wavelength
Volume
Pitch
ECE Board Exam April 1997

3131.
A government regulation in telecommunication which provide policy to improve
the provision of local exchange carrier service.
3132.
E.O. 109
3133.
Act 3846
3134.
E.O. 59
3135.
E.O. 546
3136.
3137.

ECE Board Exam April 1997

3138.
Radio communication operation service between mobile and land stations or
between mobile stations.
3139.
Land mobile satellite service
3140.
Maritime mobile service
3141.
Mobile service
3142.
Land mobile
3143.
3144.

ECE Board Exam April 1997

3145.
3146.
3147.
3148.
3149.

The smaller the f rating, the _____ light that lens can take in.
More
Intense
Less
Same

3150.
3151.

ECE Board Exam April 1997

3152.
A radio communications service use in radio regulation between specified fixed
points provided primarily for the safety of air navigation and for the regular efficient and
economical air transport.
3153.
Space operation service
3154.
Space service
3155.
Aeronautical mobile service
3156.
Aeronautical fixed service

3157.
3158.

ECE Board Exam April 1997

3159.
3160.
3161.
3162.
3163.

Harmonic suppressor connected to an antenna.
High pass filter
Low pass filter
Tank circuit
M-derived filter

3164.
3165.

ECE Board Exam April 1997

3166.
3167.
3168.
3169.
3170.

The tendency of the sound energy to spread.
Rarefaction
Reflection
Refraction
Diffraction

3171.
3172.

ECE Board Exam April 1997

3173.
An earth satellite whose period of revolution is equal to the period of rotation of
the earth about its axis.
3174.
Geosynchronous
3175.
Steerable
3176.
Passive
3177.
Active
3178.
3179.

ECE Board Exam April 1997

3180.
3181.
3182.
3183.
3184.

A figure of merit used to measure the performance of a radiation detector.
Noise equivalent power
Ripple factor
Safe factor
Quality factor

3185.
3186.

ECE Board Exam April 1997

3187.
antenna.
3188.
3189.
3190.
3191.
3192.
3193.

Radio wave concentration in the direction of the signal emitted by a directional
Back lobe radiation
Side lobe radiation
Major lobe radiation
Transmitted signal
ECE Board Exam April 1997

3194.
3195.
3196.
3197.
3198.

What is the channel bandwidth of a standard analogue telephone system?
300-500 Hz
1200 kHz
100-300 Hz
300-3400 Hz

3199.
3200.

ECE Board Exam April 1997

3201.
A satellite receives an uplink frequency of _______ MHz from a ground station of
3700 MHz.
3202.
8150 MHz
3203.
1475 MHz
3204.
2225 MHz
3205.
5925 MHz
3206.
3207.

ECE Board Exam April 1997

3208.
3209.
3210.
3211.
3212.

The outer conductor of a coaxial transmission line is always grounded at the
Input only
Input and output
Output only
Point of high SWR

3213.
3214.

ECE Board Exam April 1997

3215.
3216.
3217.
3218.
3219.

Sound intensity is given as
df/dP
dE/dp
dA/dP
dP/dA

3220.
3221.

ECE Board Exam April 1997

3222.
3223.
3224.
3225.
3226.

The lowest frequency produced by an instrument.
Harmonic
Fundamental
Midrange
0 Hz

3227.
3228.

ECE Board Exam April 1997

3229.
3230.
3231.

The reflector and director of an antenna array are considered as
Parasitic elements
Transcendental elements

3232.
3233.

Feed-points
Driven elements

3234.
3235.

ECE Board Exam April 1997

3236.
3237.
3238.
3239.
3240.

The core of the optical fiber has ______.
A medium index of refraction
A lower index of refraction than the cladding
A lower index of refraction than air
A higher index of refraction than the cladding

3241.
3242.

ECE Board Exam April 1997

3243.
3244.
3245.
3246.
3247.

What makes an antenna physically long but electrically short?
Top loading
Adding C in series
Adding L in series
All of these

3248.
3249.

ECE Board Exam April 1997

3250.
An AM transmitter is rated 100W at 100% modulation. How much power
required for the carrier?
3251.
33.33 W
3252.
66.66 W
3253.
83.33 W
3254.
100 W
3255.
3256.

ECE Board Exam April 1997

3257.
3258.
3259.
3260.
3261.

Used for time division multiplexing.
Frequency modulation
Pulsed modulation
SSB
Amplitude modulation

3262.
3263.

ECE Board Exam April 1997

3264.
3265.
3266.
3267.
3268.

A means of beyond the line-of-sight propagation of microwave signal.
Space wave
Microwave link
Troposcatter
Point-to-point

3269.
3270.
3271.
pattern?
3272.
3273.
3274.
3275.

ECE Board Exam April 1997
Which of the following refers to the smallest beam of satellite antenna’s radiation
Hemispheric beam
Spot beam
Zone beam
Global beam

3276.
3277.

ECE Board Exam April 1997

3278.
3279.
3280.
3281.
3282.

Theoretical gain of a hertzian dipole
0 dB
1.76 dB
3 dB
2.15 dB

3283.
3284.

ECE Board Exam April 1997

3285.
Satellite system or part of a satellite system, consisting of only one satellite and
the operating earth station.
3286.
Satellite system
3287.
Satellite network
3288.
Space system
3289.
Multi-satellite link
3290.
3291.

ECE Board Exam April 1997

3292.
3293.
3294.
3295.
3296.

The difference between the original and reconstructed signal gives rise to
S factor
Quantizing noise
S/N
Fade margin

3297.
3298.

ECE Board Exam April 1997

3299.
An area in the memory used for temporary storage of information, on “Last in
First out” basis.
3300.
Core
3301.
Register
3302.
Flag
3303.
Stack
3304.

3305.

ECE Board Exam April 1997

3306.
3307.
3308.
3309.
3310.

Refers to a land station in a maritime mobile service
Coast station
Ship earth station
Coast earth station
Maritime station

3311.
3312.

ECE Board Exam April 1997

3313.
3314.
3315.
3316.
3317.

Modulation in which no signal is present between pulses
Pulse modulation
QAM
PSK
FSK

3318.
3319.

ECE Board Exam April 1997

3320.
In the designation of bandwidth and emission, what letter in the first symbol
represents a double-sideband type of modulation?
3321.
A
3322.
B
3323.
C
3324.
H
3325.
3326.

ECE Board Exam April 1997

3327.
Loss due to the diffraction of light when it strikes on the irregularities formed
during the manufacturing process of the fiber optics.
3328.
Absorption loss
3329.
Attenuation
3330.
Bending loss
3331.
Rayleigh scattering loss
3332.
3333.

ECE Board Exam April 1997

3334.
3335.
3336.
3337.
3338.
3339.

What is the unit of electric field strength?
Watt/meter
Ohms/meter
Ampere/meter
Watt/meter2
No answer

3340.
3341.

ECE Board Exam April 1997

3342.
Refers to the first generation of local loop system in telecommunication
technology.
3343.
GSM
3344.
DECT
3345.
Analogue cellular
3346.
TACS
3347.
3348.

ECE Board Exam April 1997

3349.
An area on the surface of the earth within which the bore sight of the steerable
satellite beam intended to be pointed
3350.
Effective boresight area
3351.
Countour boresight are
3352.
Coordination boresight are
3353.
Equivalent boresight area
3354.
3355.

ECE Board Exam April 1997

3356.
3357.
3358.
3359.
3360.

For a sample rate of 40 kHz, determine the maximum analog input frequency
30 kHz
40 kHz
20 kHz
10 kHz

3361.
3362.

ECE Board Exam April 1997

3363.
3364.
3365.
3366.
3367.

An antenna that can only receive a television signal.
Isotropic antenna
TVRO
Reference antenna
Yagi antenna

3368.
3369.

ECE Board Exam April 1997

3370.
Halo is also called
3371.
Flare
3372.
Dark current
3373.
Glitch
3374.
Ghost
3375. Test Yourself – Exam 05
3376.
3377.

ECE Board Exam April 1998

3378.

Space diversity transmission means transmitting and receiving on _______.

3379.
3380.
3381.
3382.

Two or more antennas operating on two different frequencies
Two or more identical frequencies
Two or more antennas operating on the same frequency
Two or more different frequency

3383.
3384.

ECE Board Exam April 1998

3385.
An increase in the effective power radiated by an antenna in a certain desired
direction at the expense of power radiated in other directions.
3386.
Antenna gain
3387.
Antenna back lobe ration
3388.
Antenna total ration
3389.
Antenna efficiency
3390.
3391.

ECE Board Exam April 1998

3392.
3393.
3394.
3395.
3396.

A radio land station in the land mobile service
Mobile station
Land station
Base station
Ship earth station

3397.
3398.

ECE Board Exam April 1998

3399.
3400.
3401.
3402.
3403.

A major and basic advantage for the use of a klystron.
High power
Efficiency
Lesser noise
Cheaper

3404.
3405.

ECE Board Exam April 1998

3406.
3407.
3408.
3409.
3410.

A band where most military satellite often operate
Ku
C
X
L

3411.
3412.

ECE Board Exam April 1998

3413.
3414.
3415.
3416.

The final power amplifier in an FM transmitter usually operates class ______.
AB
C
B

3417.

A

3418.
3419.

ECE Board Exam April 1998

3420.
3421.
3422.
3423.
3424.

In television broadcasting vivid strong colors are often referred as _______.
Saturation
Hue
Chrominance
Luminance

3425.
3426.

ECE Board Exam April 1998

3427.
Where do the maximum current and minimum voltage values on a resonant Hertz
dipole exist?
3428.
Center of the antenna
3429.
Near the end of the antenna
3430.
Near the center of the antenna
3431.
Ends of the antenna
3432.
3433.

ECE Board Exam April 1998

3434.
How can the antenna efficiency of an HF grounded vertical antenna be made
comparable to that of a half-wave antenna?
3435.
By lengthening the vertical
3436.
By installing a good ground radial system
3437.
By shortening the vertical
3438.
By isolating the coax shield from ground
3439.
3440.

ECE Board Exam April 1998

3441.
3442.
3443.
3444.
3445.

At what distance is VHF propagation normally limited?
Around 500 miles
Around 1500 miles
Around 2000 miles
Around 1000 miles

3446.
3447.

ECE Board Exam April 1998

3448.
3449.
3450.
3451.
3452.

What is meant by the term antenna efficiency?
Efficiency = effective radiated power/transmitter output x 100%
Efficiency = radiation resistance/ transmission resistance
Efficiency = total resistance/radiation resistance x 100%
Efficiency = radiation resistance/total resistance x 100%

3453.
3454.

ECE Board Exam April 1998

3455.
This is referred to as a fixed radio station that broadcasts program material from
studio to transmitter by radio link.
3456.
Aural BC intercity relay
3457.
Aural broadcast STL
3458.
Shortwave station
3459.
Remote-pickup
3460.
3461.

ECE Board Exam April 1998

3462.
3463.
3464.
3465.
3466.

What law does a light traveling in air optical fiber follow?
Millman
Snell’s
Maxwell
Huygen

3467.
3468.

ECE Board Exam April 1998

3469.
Which of the following is designated as the international distress, safety and
calling frequency for radio telephony for stations of the maritime mobile service when using
frequencies in the authorized bands between 156 and 174 MHz?
3470.
165.8 MHz
3471.
156.8 MHz
3472.
158.6 MHz
3473.
168.5 MHz
3474.
3475.

ECE Board Exam April 1998

3476.
A device that connects two dissimilar networks and performs the protocol
conversion.
3477.
Gateway
3478.
Coupler
3479.
Transformer
3480.
Converter
3481.
3482.

ECE Board Exam April 1998

3483.
The use of telecommunication for the transmission of signals to initiate, modify or
terminate functions of equipment at a distance.
3484.
Tracking
3485.
space command
3486.
Telecommand
3487.
Trunking

3488.
3489.

ECE Board Exam April 1998

3490.
3491.
3492.
3493.
3494.

Best described a dip-meter.
A variable LC oscillator with metered feedback current
An SWR meter
A counter
A field strength meter

3495.
3496.

ECE Board Exam April 1998

3497.
3498.
3499.
3500.
3501.

Refers to an emission designation for facsimile?
J3E and F4E
A3J and A4E
A3E and F3C
R3E and A3E

3502.
3503.

ECE Board Exam April 1998

3504.
3505.
3506.
3507.
3508.

How does a SSB transmitter output power normally expressed?
Average power
In terms of peak envelop power
In terms of peak-to-peak power
Peak power

3509.
3510.

ECE Board Exam April 1998

3511.
In satellite communication, the Geostationary satellites are conveniently located
with respect to the equator at _______.
3512.
45 degrees latitude
3513.
90 degrees latitude
3514.
0 degrees latitude
3515.
5 degrees latitude
3516.
3517.

ECE Board Exam April 1998

3518.
Known as the technique for adding a series inductor at or near the center of an
antenna element in order to cancel the capacitive reactance of an antenna.
3519.
Dipole
3520.
Center loading
3521.
Reflector
3522.
loading coil
3523.
3524.

ECE Board Exam April 1998

3525.
What is meant by the term antenna bandwidth
3526.
Antenna length divided by the number of elements.
3527.
The angle between the half-power radiation points
3528.
The frequency range over which and antenna can be expected to perform
well
3529.
The angle formed between two imaginary line drawn through the ends of the
elements
3530.
3531.

ECE Board Exam April 1998

3532.
3533.
3534.
3535.
3536.

A multiple access technique used in GSM cellular system
TACS
FDMA
TDMA
CDMA

3537.
3538.

ECE Board Exam April 1998

3539.
Refers to an effect of selective fading.
3540.
A fading effect caused by phase differences between radio wave components
of the same transmission, as experienced at the receiving station.
3541.
A fading effect caused by small changes in beam heading at the receiving station.
3542.
A fading effect caused by the time differences between the receiving and
transmitting stations.
3543.
A fading effect caused by large changes in the height of the ionosphere, as
experienced at the receiving station.
3544.
3545.

ECE Board Exam April 1998

3546.
3547.
3548.
3549.
3550.

Where the voltage node of a half-wave antenna does exists?
At feed point
Near the center
At center
Near the feed point

3551.
3552.

ECE Board Exam April 1998

3553.
3554.
3555.
3556.
3557.

This is a flexible vertical rod antenna commonly used on mobiles.
Marconi
Hertz
Whip
Ground plane

3558.
3559.

ECE Board Exam April 1998

3560.
Referred to as an average power from the radio transmitter supplied to the antenna
transmission line taken during one radio frequency cycle under no modulation.
3561.
Carrier power
3562.
Rated power
3563.
Peak envelop power
3564.
Mean power
3565.
3566.

ECE Board Exam April 1998

3567.
3568.
3569.
3570.
3571.

_______ is a major cause of the sporadic-E condition
Temperature inversions
Sunspots
Meteors
Wind shear

3572.
3573.

ECE Board Exam April 1998

3574.
3575.
3576.
3577.
3578.

Which of the following refers to a double side band full carrier?
A3E
A3J
F3
R3A

3579.
3580.

ECE Board Exam April 1998

3581.
What is the basic qualification of an applicant for public carrier network before a
certificate of public convenience or a provisional authority is issued?
3582.
Franchise
3583.
SEC document
3584.
Business permit
3585.
Radio station license
3586.
3587.

ECE Board Exam April 1998

3588.
3589.
3590.
3591.
3592.

How wide is the spectrum bandwidth of a single GSM carrier?
100 kHz
200 kHz
50 kHz
16 kHz

3593.
3594.

ECE Board Exam April 1998

3595.
3596.

With which emission type is the capture-effect most pronounced?
CW

3597.
3598.
3599.

FM
SSB
AM

3600.
3601.

ECE Board Exam April 1998

3602.
3603.
3604.
3605.
3606.

What is a dummy antenna?
One which is used as a reference for gain measurements
And antenna used for hand-held radio
An non-directional transmitting antenna
A non-radiating load for a transmitter used for testing

3607.
3608.

ECE Board Exam April 1998

3609.
3610.
3611.
3612.
3613.

Best description of a collinear and broadside antenna radiation pattern.
Bidirectional
Perfect circle
Unidirectional
Omnidirectional

3614.
3615.

ECE Board Exam April 1998

3616.
3617.
3618.
3619.
3620.

A satellite beam that covers almost 42.4% of earths surface.
Spot beam
Global beam
Zone beam
Hemispheric beam

3621.
3622.

ECE Board Exam April 1998

3623.
3624.
3625.
3626.
3627.

The modulation technique used by GSM cellular system
Phase shift keying
Frequency shift keying
Gaussian minimum shift keying
QAM

3628.
3629.

ECE Board Exam April 1998

3630.
3631.
3632.
3633.
3634.

________ generates light beam at a specific visible frequency.
Glass fiber
Infrared
Light waves
Laser

3635.
3636.

ECE Board Exam April 1998

3637.
3638.
3639.
3640.
3641.

The most common application of satellites
Surveillance
Reconnaissance
Defense systems
Communication

3642.
3643.

ECE Board Exam April 1998

3644.
3645.
3646.
3647.
3648.

Referred to the dielectric constant of a transmission line material.
Inductance and capacitance
Velocity factor
Characteristic impedance
Propagation velocity

3649.
3650.

ECE Board Exam April 1998

3651.
Referred to as a ferrite device that can be used in lieu of a duplexer to isolate a
microwave transmitter and receiver when both are connected to the same antenna.
3652.
Isolator
3653.
Circulator
3654.
Coupler
3655.
Diode.
3656.
3657.

ECE Board Exam April 1998

3658.
_______ is more prevalent in analog signals that have steep slopes or whose
amplitudes vary rapidly.
3659.
Peak limiting
3660.
Quantization noise
3661.
Granular noise
3662.
Slope overload
3663.
3664.

ECE Board Exam April 1998

3665.
Station located on an object which is beyond and is intended to go beyond the
major portion of the earth’s atmosphere.
3666.
Terrestrial station
3667.
Space station
3668.
Satellite station
3669.
Mobile satellite station
3670.

3671.

ECE Board Exam April 1998

3672.
3673.
3674.
3675.
3676.

A radio frequency in the ultra high frequency band of the radio spectrum band.
235.50 MHz
450.50 MHz
150.50 GHz
0.31250 GHz

3677.
3678.

ECE Board Exam April 1998

3679.
Technical study which deals with production, transport and delivery of a quality
signal from source to destination.
3680.
Transmission system engineering
3681.
Communication system engineering
3682.
Telephony engineering
3683.
Telegraphic engineering
3684.
3685.

ECE Board Exam April 1998

3686.
3687.
3688.
3689.
3690.

It is used to connect computers in the same building or in same area
MAN
LAN
SWITCH
WAN

3691.
3692.

ECE Board Exam April 1998

3693.
Referred by radio regulation as the station in the mobile service not intended to be
used while in motion.
3694.
Fixed station
3695.
Base station
3696.
Land station
3697.
Coast station
3698.
3699.

ECE Board Exam April 1998

3700.
3701.
3702.
3703.
3704.

What is the mixing process?
Distortion caused by auroral propagation
The combination of two signals to produce sum and difference frequencies.
The elimination of noise in wideband receiver by phase differentiation
The elimination of noise in a wideband receiver by phase comparison

3705.
3706.

ECE Board Exam April 1998

3707.
3708.
3709.
3710.
3711.

Which of the following systems is not used in radio detection and ranging?
Frequency shift
Frequency modulation
Pulse radar
Amplitude modulation

3712.
3713.

ECE Board Exam April 1998

3714.
3715.
3716.
3717.
3718.

Considered as the main source of an internal noise.
Device imperfection
Thermal agitation
Temperature change
Flicker

3719.
3720.

ECE Board Exam April 1998

3721.
3722.
3723.
3724.
3725.

In shipboard satellite dish antennas system, azimuth is referred as the _______.
0 to 90 degrees
Vertical aiming of the antenna
North to East
Horizontal aiming of the antenna

3726.
3727.

ECE Board Exam April 1998

3728.
3729.
3730.
3731.
3732.

What is the period of a wave?
The number of degrees in tone cycle
The number of zero crossing in one cycle
The amplitude of the wave
The time required to complete one cycle

3733.
3734.

ECE Board Exam April 1998

3735.
of time
3736.
3737.
3738.
3739.
3740.
3741.

Is the total useful information processed or communicated over a specific amount
Baud rate
Bit rate
Information theory
Throughput
ECE Board Exam April 1998

3742.
What is the approximate percentage of earth coverage of a geostationary satellite
at zero degree elevation?
3743.
33.3%

3744.
3745.
3746.

45.2%
42.5%
30.5%

3747.
3748.

ECE Board Exam April 1998

3749.
This refers to an area in the memory used for temporary storage of information on
the basis of “Last in First out”.
3750.
Core
3751.
Register
3752.
Flag
3753.
Stack
3754.
3755.

ECE Board Exam April 1998

3756.
3757.
3758.
3759.
3760.

What is a driven element of an antenna?
Always the rearmost element
Always the forwardmost element
The element fed by the transmission line
The element connected to the rotator

3761.
3762.

ECE Board Exam April 1998

3763.
3764.
3765.
3766.
3767.

Which of the following term best described the overload distortion?
Peak limiting
Quantization noise
Granular noise
Slope distortion

3768.
3769.

ECE Board Exam April 1998

3770.
What do you mean by the outward flow of and energy from any source in the
form of radio waves?
3771.
Radiation
3772.
Emission
3773.
Encoding
3774.
Tracking
3775.
3776.

ECE Board Exam April 1998

3777.
Refer to the deviation of the operating frequency of a crystal oscillator from its
nominal value due to temperature variations.
3778.
Drift
3779.
Flash over

3780.
3781.

Frequency deviation
Deviation ratio

3782.
3783.

ECE Board Exam April 1998

3784.
3785.
3786.
3787.
3788.

Find the product of the following binary number 100 to 101.
11000
10100
10010
11100

3789.
3790.

ECE Board Exam April 1998

3791.
3792.
3793.
3794.
3795.

Which of the following is and impedance matching ration of coax balun?
2:8
1:2
4:1
2:1

3796.
3797.

ECE Board Exam April 1998

3798.
3799.
3800.
3801.
3802.

Quantity that do not change when a beam of light enters on e medium to another.
Frequency
Wavelength
Direction
Speed

3803.
3804.

ECE Board Exam April 1998

3805.
Which of the following described the very early standard that defines binary digits
as space/mark line condition and voltage levels?
3806.
V.4
3807.
V.2
3808.
V.1
3809.
V.5
3810.
3811.

ECE Board Exam April 1998

3812.
A form of single sideband emission where the degree of carrier suppression
enable the carrier to be reconstituted and be used for demodulation.
3813.
Half carrier single sideband emission
3814.
Full carrier single sideband emission
3815.
Reduced carrier single sideband emission
3816.
Double sideband emission

3817.
3818.

ECE Board Exam April 1998

3819.
3820.
3821.
3822.
3823.

An instrument for recording waveforms of audio frequency.
Oscilloscope
Phonoscope
Radioscope
Audioscope

3824.
3825.

ECE Board Exam April 1998

3826.
stations?
3827.
3828.
3829.
3830.

How much is the required minimum power output of an international AM BC
5 kW
30 kW
10 kW
50 kW

3831.
3832.

ECE Board Exam April 1998

3833.
3834.
3835.
3836.
3837.

What is the equivalent of decimal 51 in binary?
111011
110011
111001
100011

3838.
3839.

ECE Board Exam April 1998

3840.
One of the first satellite system catering personal based communications services
scheduled for operation.
3841.
Iridium system
3842.
Plutonium system
3843.
Indium system
3844.
Gallium system
3845.
3846.

ECE Board Exam April 1998

3847.
3848.
3849.
3850.
3851.

What do you call a circuit that controls the magnetron output?
Inverter
Impeller
Modulator
Converter

3852.
3853.

ECE Board Exam April 1998

3854.
station.
3855.
3856.
3857.
3858.

Known as the satellite transmitted signal form a satellite transponder to earth’s
Uplink
Down link
RHCP
Vertically polarized

3859.
3860.

ECE Board Exam April 1998

3861.
3862.
3863.
3864.
3865.

Which of the following colors of light rays has the shortest wavelength?
Yellow
Violet
Red
Blue

3866.
3867.

ECE Board Exam April 1998

3868.
3869.
3870.
3871.
3872.

Antenna which is not properly terminated
Isotropic
Non-resonant
Whip
Resonant

3873.
3874.

ECE Board Exam April 1998

3875.
3876.
3877.
3878.
3879.

Term in communication which is referred, “to send out in all direction”.
Announce
Broadcast
Transmit
Media

3880.
3881.

ECE Board Exam April 1998

3882.
At the ends of a half-wave antenna, what values of current and voltage exist
compared to the remainder of the antenna?
3883.
Minimum voltage and minimum current
3884.
Equal voltage and current
3885.
Minimum voltage and maximum current
3886.
Maximum voltage and minimum current.
3887.
3888.

ECE Board Exam April 1998

3889.
3890.

One of the following stands for SONET acronym in telecommunication
System optical network

3891.
3892.
3893.

Simple operation network
Synchronous optical network
System operating network

3894.
3895.

ECE Board Exam April 1998

3896.
How can intermodulation interference between two transmitters in close
proximity reduced or eliminated?
3897.
Through installing a band-pass filter in the antenna feed line
3898.
Through installing terminated circulator or ferrite isolator in the feed line of the
transmitter and duplexer
3899.
By using a class C final amplifier with high driving power
3900.
By installing a low-pass filter in the antenna feed line
3901.
3902.

ECE Board Exam April 1998

3903.
What propagation condition is usually indicated when a VHF signal is received
from a station over 5000 miles away?
3904.
Moonbounce
3905.
D-layer absorption
3906.
Tropospheric ducting
3907.
Faraday rotation
3908.
3909.
3910.
______.
3911.
3912.
3913.
3914.

ECE Board Exam April 1998
In radio High frequency communications the higher the radio frequency the
Higher it can reach
Shorter it can reach
Effect is null
Longer it can reach

3915.
3916.

ECE Board Exam April 1998

3917.
3918.
3919.
3920.
3921.

The signal to noise ratio that is required for a satisfactory television reception.
30 dB
40 dB
10 dB
20 dB

3922.
3923.

ECE Board Exam April 1998

3924.
3925.

What is meant by referring to electromagnetic waves as horizontally polarized?
The electric field is parallel to the earth

3926.
3927.
3928.

Both the electric and magnetic fields are vertical
Both the electric and magnetic fields are horizontal
The magnetic fields is parallel to the earth

3929.
3930.

ECE Board Exam April 1998

3931.
3932.
3933.
3934.
3935.

What is emission F3F?
Facsimile
Modulated CW
RTTY
Television

3936.
3937.

ECE Board Exam April 1998

3938.
3939.
3940.
3941.
3942.

How can receiver desensitizing be reduced?
Increase the receiver bandwidth
Ensure good RF shielding between the transmitter and receiver
Increase the transmitter audio gain
Decrease the receiver squelch, gain.

3943.
3944.

ECE Board Exam April 1998

3945.
3946.
3947.
3948.
3949.

Circuit used to amplify the optical signal in fiber optics communications links.
Attenuator
Optical repeater
Optical amplifier
Generator

3950.
3951.

ECE Board Exam April 1998

3952.
receiver?
3953.
3954.
3955.
3956.

What do you call the single booster installed on the antenna dish of satellite
Low noise amplifier
Single amplifier
Noise amplifier
Rectifier

3957.
3958.

ECE Board Exam April 1998

3959.
3960.
3961.
3962.
3963.

Term for the transmission of printed pictures by radio?
Facsimile
ACSSB
Xerography
Television

3964.
3965.

ECE Board Exam April 1998

3966.
An interfering current in a telegraph or signaling channel due to telegraph or
signaling current by another channel.
3967.
Crosstalk
3968.
Noise current
3969.
Crossfire
3970.
Intermodulation
3971.
3972.

ECE Board Exam April 1998

3973.
Where is the noise generated that primarily determines the signal-to-noise ratio in
a VHF (150 MHz) marine-band receiver?
3974.
In the ionosphere
3975.
In the receiver rear end
3976.
In the receiver front end
3977.
In the atmosphere
3978.
3979.

ECE Board Exam April 1998

3980.
3981.
3982.
3983.
3984.

Known as the data transfer scheme that used handmaking principle.
Synchronous data transfer scheme
DMA data transfer scheme
Asynchronous data transfer scheme
Uninterrupted data transfer scheme

3985.
3986.

ECE Board Exam April 1998

3987.
3988.
3989.
3990.
3991.

Type of modulation used in TV broadcast visual transmitter.
Pulse modulation
DSBFC
Vestigial sideband
SSBFC

3992.
3993.

ECE Board Exam April 1998

3994.
A transmitter supplies 8 kW to the antenna when it is unmodulated, determine the
total radiated power when modulated at 90%.
3995.
5 kW
3996.
20 kW
3997.
15 kW
3998.
8.36 kW
3999.

4000.

ECE Board Exam April 1998

4001.
4002.
4003.
4004.
4005.

Best describe as an amplifier used in radio telephony.
Magnifier
Class B
Class C
Class A

4006.
4007.

ECE Board Exam April 1998

4008.
The latest government regulation in the telecommunication which provides policy
for the provision of local exchange carrier service.
4009.
E.O. 546
4010.
E.O. 109
4011.
Act 3948
4012.
E.O. 59
4013.
4014.

ECE Board Exam April 1998

4015.
4016.
4017.
4018.
4019.

Referred to as the stage in the radio receiver that contributes most of the noise.
IF amplifier
Supply stage
Speaker
Mixer

4020.
4021.

ECE Board Exam April 1998

4022.
4023.
4024.
4025.
4026.

The frequency tolerance of an AM radio broadcast station
200 Hz
2000 Hz
20 Hz
2 Hz

4027.
4028.

ECE Board Exam April 1998

4029.
What are electromagnetic waves?
4030.
A wave consisting of two magnetic fields at right angles to each other
4031.
A wave consisting of an electric field and a magnetic field at right angles to
each other.
4032.
Alternating currents in the core of an electromagnet
4033.
A wave consisting of two electric fields at right angles to each other
4034.
4035.

ECE Board Exam April 1998

4036.
4037.
4038.
4039.
4040.

What is the frequency range of C-band?
10.95 to 14.5 GHz
27.5 to 31 GHz
3.4 to 6.424 GHz
1.53 to 2.7 GHz

4041.
4042.

ECE Board Exam April 1998

4043.
Determine from the following the basic mode of transmission system in the public
data network in which data are transferred from the source to the network and from the
network to the destination in the frame format.
4044.
Voice mode
4045.
Asynchronous mode
4046.
Synchronous mode
4047.
Packet mode
4048.
4049.

ECE Board Exam April 1998

4050.
Refers to a type of beam antenna which uses two or more straight elements
arranged in line with each other.
4051.
Dipole antenna
4052.
Yagi antenna
4053.
Whip antenna
4054.
Rhombic antenna
4055.
4056.

ECE Board Exam April 1998

4057.
4058.
4059.
4060.
4061.

What is a frequency discriminator?
A circuit for filtering two closely adjacent signals
A circuit for detecting FM signals
An FM generator
An automatic bandswitching circuit.

4062.
4063.

ECE Board Exam April 1998

4064.
4065.
4066.
4067.
4068.

These are used to connect non-ISDN equipment ot ISDN line.
Digipeaters
Terminal adapters
Local repeaters
Terminal repeaters

4069.
4070.

ECE Board Exam April 1998

4071.

The executive branch of government in charge of policy making in the

telecommunications.
4072.
National telecommunications commission
4073.
Telecommunications control bureau
4074.
Department of transportation and communications
4075.
Bureau of telecommunications
4076.
4077.
4078.
4079.
4080.
4081.
4082.
4083.
4084.
4085.
4086.
4087.
4088.
4089.
4090.
4091.
4092.
4093.
4094.
4095.
4096.
4097.
Test Yourself – Exam 06
4098.
4099.
ECE Board Exam April 1998
4100.
4101.
When adjusting an RF filter on a transmitter using a dummy load, how much
watts dissipation should it stand to test a 150 watts transmitter?
4102.
4103.
75 watts
4104.
300 watts
4105.
50 watts
4106.
150 watts
4107.
4108.

ECE Board Exam April 1998

4109.
4110.
4111.
4112.
4113.

When does broadcast station conduct and equipment test?
During day time
During night time
At any time
During experimental period

4114.
4115.

ECE Board Exam April 1998

4116.
4117.
4118.
4119.
4120.

Channel 7 of the regular television channel belongs to which band?
Low VHF band
High VHF band
Low UHF band
High UHF band

4121.
4122.

ECE Board Exam April 1998

4123.
Which of the following is one of the possible causes for a slow drift of frequency
in a self exited transmitter oscillator circuits resulting to a poor frequency stability?
4124.
Poor soldered connections
4125.
Power supply voltage changes
4126.
Loose connections in the oscillator, amplifier, or antenna circuits
4127.
DC and RF heating of resistors, causing then to change values.
4128.
4129.

ECE Board Exam April 1998

4130.
A third symbol radio emission which represent telephone transmission including
sound broadcasting.
4131.
W
4132.
F
4133.
C
4134.
E
4135.
4136.

ECE Board Exam April 1998

4137.
4138.
4139.
4140.
4141.

Which of the following is not a common microwave application?
Radar
Data transmission
Space communications
Mobile radio

4142.
4143.

ECE Board Exam April 1998

4144.
4145.
4146.
4147.
4148.

Which of the following is referred to as a radio emission without sidebands
Analog
Carrier
Data
Voice

4149.
4150.

ECE Board Exam April 1998

4151.
a cable?
4152.
4153.
4154.
4155.

Ho w many times bigger does the bandwidth of a fiber optic multimode have over
50 times bigger
100 times bigger
10 times bigger
5 times bigger

4156.
4157.

ECE Board Exam April 1998

4158.
4159.
4160.
4161.
4162.

Type of antenna which is normally used for satellite tracking service.
Omni
Helical
Yagi
Dipole

4163.
4164.

ECE Board Exam April 1998

4165.
One of the following is referred to as a major component of an optical time
domain reflectometer
4166.
Pulse generator and vertical plate
4167.
Laser and horizontal plate
4168.
Pulse generator laser
4169.
Vertical and horizontal plate
4170.
4171.

ECE Board Exam April 1998

4172.
4173.
4174.
4175.
4176.

One of the commonly used domain in the internet service.
Yahoo
http
com
www

4177.
4178.

ECE Board Exam April 1998

4179.
What is meant by the term radiation resistance for an antenna?
4180.
The resistance in the trap coils to received signal
4181.
An equivalent resistance that would dissipate the same amount of power as
that radiated from an antenna
4182.
The specific impedance of the antenna
4183.
Losses in the antenna elements and feed line
4184.
4185.

ECE Board Exam April 1998

4186.

Referred to an oscillator signal “leak through” from a properly neutralized

amplifier such as a master oscillator power amplifier.
4187.
Carrier
4188.
Stray signal
4189.
Back wave
4190.
Loss wave
4191.
4192.

ECE Board Exam April 1998

4193.
An advantage of optic fiber rejecting an induced noise signals from magnetic field
or solar storms flux.
4194.
Electric hazard
4195.
Cross talk
4196.
Immunity to noise
4197.
Shielding
4198.
4199.

ECE Board Exam April 1998

4200.
What kind of effect is referred to a varying light producing a varying voltage
output of a detector?
4201.
Current effect
4202.
Voltage effect
4203.
Resistive effect
4204.
Photovoltaic effect
4205.
4206.

ECE Board Exam April 1998

4207.
______ is known to be the first satellite capable of receiving and transmitting
simultaneously.
4208.
Syncom I
4209.
Telstar I
4210.
Score
4211.
Aguila
4212.
4213.
4214.
_______.
4215.
4216.
4217.
4218.
4219.
4220.

ECE Board Exam April 1998
The extremely high frequency (EHF) band is in the radio spectrum range of
30 to 300 kHz
30 to 300 GHz
3 to 30 MHz
3 to 30 GHz
ECE Board Exam April 1998

4221.
4222.
4223.
4224.
4225.

One of the following is not among the advantages of series modulation
No transformer
Suppressed white noise
Simple
Modulates any frequency

4226.
4227.

ECE Board Exam April 1998

4228.
What do you call the service area of a standard AM broadcast where fading is
allowed but not objectionable co-channel interference?
4229.
Experimental
4230.
Secondary
4231.
Tertiary
4232.
Primary
4233.
4234.

ECE Board Exam April 1998

4235.
4236.
4237.
4238.
4239.

A third symbol emission which represent television.
C
D
F
A

4240.
4241.

ECE Board Exam April 1998

4242.
In telecommunications when we call data communications it means the
transmission of________.
4243.
Voice and video
4244.
Voice
4245.
Video
4246.
Computer data
4247.
4248.

ECE Board Exam April 1998

4249.
If frequency range of 401.000MHz to 401.050MHz has to be channelized at 12.5
kHz between channel, what is the center of its first channel from the lower limit?
4250.
401.125MHz
4251.
401.00625MHz
4252.
401.025MHz
4253.
401.0125MHz
4254.
4255.

ECE Board Exam April 1998

4256.

Determine the effective radiated power of 20 kW TV broadcast transmitter whose

antenna has a field gain of 2.
4257.
40 kW
4258.
80,000 watts
4259.
40,000 watts
4260.
8,000 watts
4261.
4262.

ECE Board Exam April 1998

4263.
In indication signal for a handshake form the DCE to the DTE in response to an
active condition for the request to send a signal.
4264.
Data transmission
4265.
Clear to send
4266.
Receive data
4267.
Data set ready
4268.
4269.

ECE Board Exam April 1998

4270.
In amplitude modulation technique the unmodulated carrier is referred to as
having ______.
4271.
100% modulation
4272.
0% modulation
4273.
50% modulated
4274.
Over modulated
4275.
4276.

ECE Board Exam April 1998

4277.
One of the following is not among the major components required on board ship
under the global maritime distress and safety system.
4278.
On board radio facilities
4279.
Radio operator telegraphy onboard
4280.
Shore base facilities
4281.
Radio personnel on board
4282.
4283.

ECE Board Exam April 1998

4284.
In what form does the information of data communications is transmitted between
two points?
4285.
Alphanumeric form
4286.
Alphabetic form
4287.
Numeric form
4288.
Binary form
4289.
4290.

ECE Board Exam April 1998

4291.
Width of frequency band just enough to ensure the transmission of information at
a required rate and quality required, and under a specified condition and class of emission.
4292.
Occupied bandwidth
4293.
Transmission bandwidth
4294.
Necessary bandwidth
4295.
Frequency bandwidth
4296.
4297.

ECE Board Exam April 1998

4298.
Refers to one of the front end circuit of a VHF TV superheterodyne receiver
which is usually a separate circuit coupled to the mixer.
4299.
Antenna feed
4300.
AGC
4301.
RF amplifier
4302.
Local oscillator
4303.
4304.

ECE Board Exam April 1998

4305.
4306.
4307.
4308.
4309.

All bits in character are sent and received ______ in serial port.
In groups of 3 bits
One at a time
In groups of 2 bits
Simultaneously

4310.
4311.

ECE Board Exam April 1998

4312.
One of the following is a possible cause of an abrupt frequency variation in a self
exited transmitter oscillator circuits resulting to a poor frequency stability to hold a constant
frequency oscillation.
4313.
Heating and expansion of oscillator coil
4314.
DC and RF ac heating of resistors which cause change in values
4315.
Heating of capacitor in the oscillator
4316.
Loose connections in the oscillator, amplifier, or antenna circuits.
4317.
4318.

ECE Board Exam April 1998

4319.
Which of the following parts of the radio receiver represent the component that
extracts the desire RF signal from the electromagnetic wave?
4320.
AF amplifier
4321.
Antenna
4322.
Detector
4323.
Crystal
4324.
4325.

ECE Board Exam April 1998

4326.
It is an average power of a radio transmitter supplied to the antenna transmission
line taken during a long sufficient interval of time and compared with the lowest frequency
encountered in the modulation, taken under the normal operating conditions.
4327.
Carrier power
4328.
Rated power
4329.
Mean power
4330.
Peak envelop power
4331.
4332.

ECE Board Exam April 1998

4333.
Determine from the following radio frequency that falls under the very high
frequency band of the radio spectrum.
4334.
345.00 MHz
4335.
144.50 MHz
4336.
235.50 MHz
4337.
450.00 MHz
4338.
4339.

ECE Board Exam April 1998

4340.
4341.
4342.
4343.
4344.

What is the typical number of bits in a static memory location?
1
2
16
8

4345.
4346.

ECE Board Exam April 1998

4347.
4348.
4349.
4350.
4351.

What controls the contrast of a television cathode ray picture?
AFC
video stage gain
Audio gain control
CRT bias

4352.
4353.

ECE Board Exam April 1998

4354.
Determine the dB gain of a receiving antenna which delivers a microvolt signal to
a transmission line over that of an antenna that delivers a 20 microvolt signal under identical
circumstances.
4355.
10 dB
4356.
6 dB
4357.
3 dB
4358.
8 dB
4359.
4360.

ECE Board Exam April 1998

4361.
4362.
4363.
4364.
4365.

Refers to one of a commonly used internet service domain.
www
http
gov
infoseek

4366.
4367.

ECE Board Exam April 1998

4368.
A law that specifically requires the service of a duly registered electronics and
communications engineer in the designing installation and construction, operation and
maintenance of radio stations.
4369.
Act 3846
4370.
LOl 1000
4371.
R.A. 5734
4372.
Dept. order 88
4373.
4374.

ECE Board Exam April 1998

4375.
4376.
4377.
4378.
4379.

Which band does channel 14 of the television channel belong?
High VHF band
EHF band
UHF band
Low VHF band

4380.
4381.

ECE Board Exam April 1998

4382.
How many ship’s area is designated in the implementation of the global maritime
distress and safety system.
4383.
Four
4384.
Six
4385.
Three
4386.
Two
4387.
4388.

ECE Board Exam April 1998

4389.
4390.
4391.
4392.
4393.

What kind of receiver is used in conventional telephone handset?
Capacitor
Electromagnetic
Carbon
Ceramic

4394.
4395.

ECE Board Exam April 1998

4396.

Determine the lower half-power frequency of a class-C amplifier having upper

half-power frequency of 10.025 MHz, a resonant frequency 5 MHz and a circuit Q of 10.
4397.
1.0025 MHz
4398.
10.525 MHz
4399.
0.5 MHz
4400.
10 MHz
4401.
4402.

ECE Board Exam April 1998

4403.
This is referred to a product of simultaneous frequency and amplitude modulation
or a carrier frequency variation which produces unwanted distortion.
4404.
Absorption modulation
4405.
Simultaneous modulation
4406.
Dynamic instability
4407.
Series modulation
4408.
4409.

ECE Board Exam April 1998

4410.
4411.
4412.
4413.
4414.

Main basic components of a data communication are composed of the following.
Computer, modern and router
Computer, bridge and gateway
Transmitter, channel and receiver
Transmitter, computer and modem

4415.
4416.

ECE Board Exam April 1998

4417.
The international radio consultative committee is referred to in international radio
communication as ______.
4418.
IRCC
4419.
ITU
4420.
IRR
4421.
CCIR
4422.
4423.

ECE Board Exam April 1998

4424.
Refers to a continuous tone generated in a local exchange terminal through a
combination of two frequencies 350 Hz, and 440 Hz.
4425.
Busy tone
4426.
Call waiting tone
4427.
Dial tone
4428.
Standard tone
4429.
4430.

ECE Board Exam April 1998

4431.

One of the advantages of fiber optic which is referred to the volume of capacity of

signals it can carry.
4432.
Security
4433.
Weight
4434.
Bandwidth
4435.
Physical size
4436.
4437.

ECE Board Exam April 1998

4438.
Assume a frequency range of 401.000 MHz to 401.050 MHz, if you apply 25 kHz
channeling plan, determine the center frequency of the first channel from the lower limit.
4439.
401.010 MHz
4440.
401.0125 MHz
4441.
401.025 MHz
4442.
401.00625 MHz
4443.
4444.

50 ECE Board Exam April 1998

4445.
The stability of transmitted signal from a simple Hartley oscillator single
transmitter which is coupled to and antenna wire affected by ______.
4446.
Chirping of oscillator
4447.
Closer coupling between the oscillator and the antenna.
4448.
Location of antenna
4449.
Material of antenna
4450.
4451.

ECE Board Exam April 1998

4452.
Refers to the first symbol in an emission designation with an amplitude modulated
main carrier represented by letter H.
4453.
Single sideband suppressed carrier
4454.
Double sideband full carrier
4455.
Independent sideband
4456.
Double sideband
4457.
4458.

ECE Board Exam April 1998

4459.
Assume a frequency range of 405.0125 MHz to 405.0875 MHz and 25 kHz
channeling plan, determine the center frequency of the second channel from the lower limit.
4460.
405.030 MHz
4461.
405.025 MHz
4462.
405.050 MHz
4463.
405.075 MHz
4464.
4465.

ECE Board Exam April 1998

4466.
An entity, relying on the transmission, switching and local distribution facilities of
local exchange and inter-exchange operators, and overseas carriers, offers enhanced services
beyond those ordinarily provided by such carriers.
4467.
International carrier
4468.
Value-added service provided
4469.
Inter-exchange carrier
4470.
Local exchange carrier
4471.
4472.

ECE Board Exam April 1998

4473.
4474.
4475.
4476.
4477.

Which of the following refers to full duplex transmission?
One at a time transmission
Two transmission medium
Intermittent transmission
Two way simultaneous transmission

4478.
4479.

ECE Board Exam April 1998

4480.
What is the first symbol of a radio signal transmission having an amplitude
modulated signal carrier, double side band?
4481.
C
4482.
B
4483.
H
4484.
A
4485.
4486.
4487.
wire line
4488.
4489.
4490.
4491.
4492.
4493.

ECE Board Exam April 1998
Best choice of transmission line component to couple a coaxial line to a parallelShorting
Balun
Slotted line
Directional coupler
ECE Board Exam April 1998

4494.
Which of the following refers to the video signal amplitude that determines the
quality of the picture?
4495.
Chrominance
4496.
Luminance
4497.
Brightness
4498.
Contrast
4499.
4500.

ECE Board Exam April 1998

4501.
________ is the method of encoding audio signals used in US standard 1544
kbit/s 24 channel PCM systems.
4502.
Shannon’s law
4503.
A-law
4504.
Newton’s law
4505.
Mu-law
4506.
4507.
4508.
______.
4509.
4510.
4511.
4512.

ECE Board Exam April 1998
In radio regulation, the first symbol in the designation of radio emission is
Bandwidth
Nature of signal(s) modulation the main carrier
Type of modulation of the main carrier
Type of information to be transmitted

4513.
4514.

ECE Board Exam April 1998

4515.
4516.
4517.
4518.
4519.

Who is the principal administrator of republic act 7925?
BOC
DOTC
Congress
NTC

4520.
4521.

ECE Board Exam April 1998

4522.
What is the term for the ration of the radiation resistance of an antenna to the total
resistance of the system?
4523.
Effective radiated power
4524.
Beamwidth
4525.
Radiation conversion loss
4526.
Antenna efficiency
4527.
4528.

ECE Board Exam April 1998

4529.
4530.
4531.
4532.
4533.

Where does the AM broadcast band located in the spectrum band?
HF band
VHF band
LF band
MF band

4534.
4535.

ECE Board Exam April 1998

4536.

What determines the velocity factor in transmission line?

4537.
4538.
4539.
4540.

The center conductor resistivity
Dielectrics in the line
The termination impedance
The line length

4541.
4542.

ECE Board Exam April 1998

4543.
Refers to an address that identifies a server on the network and a particular
document on the server
4544.
Hypertext
4545.
HTML
4546.
Wide area network
4547.
Uniform resource locator
4548.
4549.

ECE Board Exam April 1998

4550.
Type of emission produced by one of the early radio transmitter in trains of
damped RF ac waves where its oscillator is coupled to a long wire antenna, normally used in
radio telegraph and having sidebands on its carrier.
4551.
Digital emission
4552.
Key emission
4553.
Cycle emission
4554.
Spark emission
4555.
4556.

ECE Board Exam April 1998

4557.
Is a kind of satellite which has a period of revolution equivalent to the period of
rotation of the earth about its axis.
4558.
Passive satellite
4559.
Synchronous satellite
4560.
Active satellite
4561.
Geosynchronous satellite
4562.
4563.

ECE Board Exam April 1998

4564.
Electromagnetic waves of frequencies arbitrarily lower than 3,000 GHz,
propagated in space without artificial guide.
4565.
Space waves
4566.
Terrestrial waves
4567.
Mobile
4568.
Hertzian waves
4569.
4570.

ECE Board Exam April 1998

4571.
4572.
4573.
4574.
4575.

Frequencies above ______ kHz, are referred to as the radio frequencies.
20
2
10
200

4576.
4577.

ECE Board Exam April 1998

4578.
Who is responsible in the correctness and accuracy of transmitted information
content over a data communication?
4579.
The channel
4580.
The transmitter and receiver
4581.
The modem
4582.
The bridge
4583.
4584.

ECE Board Exam April 1998

4585.
What is meant by the term deviation ratio?
4586.
The ratio of the carrier center frequency to the audio modulating frequency
4587.
The ratio of the highest audio modulating frequency to the average audio
modulating frequency
4588.
The ratio of the maximum carrier frequency deviation to the highest audio
modulation frequency
4589.
The ratio of the audio modulating frequency to the center carrier frequency
4590.
4591.

ECE Board Exam April 1998

4592.
A quarter wavelength devices made of crystalline calcite that changes polarization
in the optic fiber communication.
4593.
Isolator
4594.
Retarder
4595.
Polarizer
4596.
Filters
4597.
4598.
4599.
1927
4600.
4601.
4602.
4603.
4604.
4605.

ECE Board Exam April 1998
Known as the maritime communications law which was enacted December 5,
R.A. No. 109
R.A. No. 3396
R.A. No. 7925
R.A. No. 3846
ECE Board Exam April 1998

4606.
How do you transmit through multiplexing, a thousand of voice channel
information over a single fiber optic using on e wavelength?
4607.
Polar division
4608.
Time division
4609.
Fiber division
4610.
Frequency division
4611.
4612.

ECE Board Exam April 1998

4613.
In regulation of public telecommunications carrier such as in the evaluation of
new entrant, the following consideration shall be given emphasis to _______.
4614.
Legal, technical and citizenship
4615.
Technical, citizenship and kind of service
4616.
Citizenship, capacity and financial
4617.
Technical, legal and financial
4618.
4619.

ECE Board Exam April 1998

4620.
One of the following is a high powered RF ac basic transmitter that has two or
more stages, the oscillator stage which determines the frequency opereation and RF amplifier
stage or stages that develop the high power output. The purpose of which is to develop a
good frequency stability.
4621.
Goldsmith
4622.
MOPA
4623.
Alexanderson
4624.
Hartley
4625.
4626.

ECE Board Exam April 1998

4627.
What is the meaning of the term velocity factor of a transmission line?
4628.
The index of shielding for coaxial cable
4629.
The velocity of the wave on the transmission line multiplied by the velocity of
light in vacuum
4630.
The ratio of the characteristic impedance of the line to the terminating impedance
4631.
The velocity of the wave on the transmission line divided by the velocity of
light in a vacuum
4632.
4633.

ECE Board Exam April 1998

4634.
4635.
4636.
4637.
4638.

Which of the following determines the characteristics of a transmission line?
Inductance
Capacitance
Physical dimension
Length

4639.
4640.

ECE Board Exam April 1998

4641.
One of the following is among the types of fiber optics used in electronics
communication.
4642.
Step-index multimode
4643.
Graded-index multimode
4644.
Semi-graded multimode
4645.
Single mode
4646.
4647.

ECE Board Exam April 1998

4648.
Which of the following refers to the smallest beam of a satellite antenna’s
radiation pattern
4649.
Global beam
4650.
Spot beam
4651.
Zone beam
4652.
Hemispheric beam
4653.
4654.

ECE Board Exam April 1998

4655.
One of the FM signal generator control which varies the phase of the modulating
voltage applied to the oscillator of the sweep generator
4656.
Band control
4657.
Phase control
4658.
Marker amplitude control
4659.
Sweep output control
4660.
4661.

ECE Board Exam April 1998

4662.
4663.
4664.
4665.
4666.

What consists the front-end circuit of a VHF TV superheterodyne receiver?
Mixer, RF amplifier and AFC?
RF amplifier, Band pass filter and mixer
Local oscillator, mixer and RF amplifier
Local oscillator, AGC and antenna

4667.
4668.

ECE Board Exam April 1998

4669.
One of the following prevents a transmitter from emitting a signal that interferes
with other stations on frequency during the test.
4670.
Use of low height antenna
4671.
Use of grounded antenna
4672.
Use of dummy antenna
4673.
Use of shielded antenna radiator

4674.
4675.

ECE Board Exam April 1998

4676.
A transmission line consisting of two conductors that have equal resistance per
unit length.
4677.
Unbalanced line
4678.
Open-wire line
4679.
Balanced line
4680.
Coaxial line
4681.
4682.

ECE Board Exam April 1998

4683.
How do you eliminate radio frequency variation of an oscillator transmitter
caused by its supply voltage?
4684.
Use new power supply
4685.
Lossen power supply shielding
4686.
Use of regulated power supply
4687.
Use of high capacitor in the supply circuit
4688.
4689.

ECE Board Exam April 1998

4690.
4691.
4692.
4693.
4694.

Which of the following is not common transmission line impedance?
50 ohms
120 ohms
75 ohms
650 ohms

4695.
4696.

ECE Board Exam April 1998

4697.
How do you reduce the loss that is produced when light strikes a flat polished end
of a fiber optic?
4698.
By painting the surface
4699.
By inclining the surface
4700.
By cooling
4701.
By application of antireflection coating
4702.
4703.

ECE Board Exam April 1998

4704.
4705.
4706.
4707.
4708.

Best reason for pressurizing waveguides with dry air
To maintain propagation
To maintain temperature of the waveguide
To reduce the possibility of internal arcing
To increase the speed of propagation

4709.

4710.

ECE Board Exam April 1998

4711.
What is the device used in fiber optic communication which consist of a receiver
transmitter use to clean up and amplify digital data moving in one direction and another in
the opposite direction?
4712.
Optic compressors
4713.
Optic retarders
4714.
Optic isolator
4715.
Optic regenerators
4716.
4717.

ECE Board Exam April 1998

4718.
4719.
4720.
4721.
4722.

Which of the following refers to the first active satellite?
Telstar I
Echo I
Intelsat I
Sputnik I

4723.
4724.

ECE Board Exam April 1998

4725.
4726.
4727.
4728.
4729.

In modulation technique, which of the following is referred to audible pitch?
Width
Frequency
Harmonic
Amplitude

4730.
4731.

ECE Board Exam April 1998

4732.
What do you call the phenomenon in digital circuits that describe the duration of
time a digital signal passes a circuit?
4733.
Transmission time
4734.
Elapsed time
4735.
Propagation delay
4736.
Travel delay
4737.
4738.

ECE Board Exam April 1998

4739.
4740.
4741.
4742.
4743.

What is the major cause of atmospheric or static noise?
Sunspots
Airplanes
Meteor showers
Thunderstorm

4744.
4745.

ECE Board Exam April 1998

4746.
4747.
4748.
4749.
4750.

Which of the following is not referred to as data terminal equipment?
Telephone set
Printers
Modem
Computer

4751.
4752.

ECE Board Exam April 1998

4753.
4754.
4755.
4756.
4757.

_______ is referred as the difference between available power and power budget?
Fade margin
Power margin
Nominal gain
Power dissipation

4758.
4759.

ECE Board Exam April 1998

4760.
The conversion of digital signal into analog for purposes of transmitting into the
telephone line is done through ______.
4761.
ISDN
4762.
Radio
4763.
RS232C
4764.
Modem
4765.
4766.

ECE Board Exam April 1998

4767.
4768.
4769.
4770.
4771.

Refers to the duration occupancy period of call during its use.
Occupancy period
Traffic time
Use time
Holding time

4772.
4773.

ECE Board Exam April 1998

4774.
4775.
4776.
4777.
4778.

In data communication the transmission of binary signals will require _______.
Same bandwidth as analog
More bandwidth than analog
Less bandwidth than analog
Bigger cable diameter

4779.
4780.

ECE Board Exam April 1998

4781.
Assuming a UHF frequency range of 405.0125 MHz to 405.0875 MHz at 25 kHz
channeling plan, how many channels can you produce?
4782.
2.5 ch.

4783.
4784.
4785.

2 ch.
4 ch.
3 ch.

4786.
4787.

ECE Board Exam April 1998

4788.
One of the following is a possible cause for a slow drift of frequency in a selfexited transmitter oscillator circuits resulting to a poor frequency stability.
4789.
Loose shielding
4790.
Heating of capacitor in the oscillator
4791.
Poor soldered connections
4792.
Faulty capacitor, resistor, tubes or resistors
4793.
4794.

ECE Board Exam April 1998

4795.
A modulation which does not follow the sine wave pattern, it produces
undesirable harmonics such as spurious emission
4796.
0% modulated
4797.
Over-modulated
4798.
Unmodulated
4799.
100% modulated
4800.
4801.
4802.
4803.
4804.
4805.

4806.
Test Yourself – Exam 07
4807.
4808.
1. How far away is the radio horizon of an antenna 100ft high?
4809. A. 14.14 mi = √2(100ft)
4810. B. 40km
4811. C. 14.14 km
4812. D. 40 mi
4813.
4814.
2. What is the maximum line-of-sight distance between a paging antenna 250 ft
high and a pager receiver 3.5ft of the ground?
4815.
A. 25 km
4816.
B.25mi = √2(250ft) + √2(3.5ft)
4817.
C. 70.73 km
4818.
D. 70.73 mi
4819.
4820.
3. What is the path attenuation between transmitter and receiver at a frequency of
1.2 Ghz and a distance of 11,000 mi?
4821. A. 119 dB
4822.
B. 115dB
4823.
C. 179dB = 96.6 + 20log(11000mi) + 20log(1.2GHz)
4824.
D. 174dB
4825.
4826.
4. What is the uplink receiver frequency if the downlink transmitter is on channel
4 (3.84 Ghz)?
4827.
A. 6.065 GHz
4828.
B. 6.84 GHz
4829.
C. 6.65 GHz
4830.
D. 6.05 GHz
4831.
4832.
5. What is the maximum theoretical data rate of the above problem if one
transponder is used for binary transmission?
4833.
A. 36 Mbps
4834.
B. 72 Mbps
4835.
C.18 Mbps
4836.
D. 144 Mbps
4837.
4838.
6. What is the guardband between transponder channels in the commercial C-band
for satellite communications?
4839.
A. 6 MHz
4840.
B. 36 MHz
4841.
C. 4 MHz
4842.
D. 2 MHz
4843.
4844.
4845.
4846.

4847.
4848.
7. What is the typical satellite transponder bandwidth?
4849.
A. 24 MHz
4850.
B. 500 MHz
4851.
C. 36 MHz
4852.
D. 48 MHz
4853.
4854.
8. What is the bandwidth available in the commercial C-band?
4855.
A. 1000 MHz
4856.
B. 36 MHz
4857.
C. 250 MHz
4858.
D. 500 MHz
4859.
4860.
9. Which of the following is the uplink frequency in C-band?
4861.
A. 5.925 GHz
4862.
B. 4.2 GHz
4863.
C. 7.425 GHz
4864.
D. 3.7 GHz
4865.
4866.
10. How many transponder channels are realized in the commercial C-band
without frequency re-use?
4867.
A. 24
4868.
B. 12
4869.
C. 36
4870.
D. 48
4871.
4872.
11. Which band of frequencies used by military for its satellites and radar?
4873.
A. C band
4874.
B. X band
4875.
C. L band
4876.
D. P band
4877.
4878.
12. For navigation as well as marine and aeronautical communications and radar,
____ band is used.
4879.
A. L
4880.
B. K
4881.
C. S
4882.
D. J
4883.
4884.
13. What is the current frequency band given most attenuation for satellite
communications?
4885.
A. Ku
4886.
B. C band
4887.
C. J
4888.
D. P
4889.

4890.
4891.
14. What satellite subsystem monitors onboard conditions such as temperature
and battery voltage and transmits this data back to a ground station for analysis?
4892.
A. Communications subsystem
4893.
B. AKM
4894.
C. TTC
4895.
D. Transponder
4896.
4897.
15. Which of the following satellite subsystem provides stabilization in orbit and
senses changes in orientation?
4898.
A. Attitude control subsystem
4899.
B. TTC
4900.
C. AKM
4901.
D. Transponder
4902.
4903.
16. What is the typical center frequency spacing between adjacent channels
(transponders) in satellites?
4904.
A. 36 MHz
4905.
B. 40 MHz
4906.
C. 500 MHz
4907.
D. 4 MHz
4908.
4909.
17. Which of the following are uplinks in the Ku band?
4910.
A. 14 to 14.5 GHz
4911.
B. 11.7 to 12.2 GHz
4912.
C. 14 to 15.5 GHz
4913.
D. 11 to 11.5 GHz
4914.
4915.
18. What is considered as the most advanced satellite system developed for
cellular telephones?
4916.
A. Iridium
4917.
B. Globalstar
4918.
C. ANIK
4919.
D. Molniya
4920.
4921.
19. What is the orbit of Motorola’s Iridium satellite system?
4922.
A. Polar
4923.
B. Equatorial
4924.
C. Inclined elliptical
4925.
D. Inclined equatorial
4926.
4927.
20. What band of frequencies do these satellites operate?
4928. A. L band
4929.
B. Ka band
4930.
C. C band
4931.
D. Ku band

4932.
4933.
4934.
21. Iridium satellites can provide data communications of up ____ bps data rate.
4935.
A. 1200
4936.
B. 4800
4937.
C. 2400
4938.
D. 3840
4939.
4940.
22. What satellite system is also known as Navstar?
4941.
A. GPS
4942.
B. Iridium
4943.
C. Globalstar
4944.
D. Intelsat
4945.
4946.
23. What is the orbit height of a GPS satellite?
4947.
A. 10,898 nmi = 12,541.2 mi = 20,183 km
4948.
B. 10,898 mi
4949.
C. 10,898 km
4950.
D. 10, 898 m
4951.
4952.
24. What is the orbital period of each satellite in the GPS constellation?
4953.
A. 6 h
4954.
B. 12 h
4955.
C. 5 h
4956.
D. 15 h
4957.
4958.
25. What term is normally associated with specifying the location of a celestial
body in space?
4959.
A. Constellation
4960.
B. Galaxy
4961.
C. Satellite
4962.
D. Ephemeris
4963.
4964.
26. What is the angle of inclination of GPS system?
4965.
A. 55Ëš
4966.
B. 65Ëš
4967.
C. 105Ëš
4968.
D. 45Ëš
4969.
4970.
27. What material is most often used for the outer covering of coaxial cables?
4971.
A. PVC
4972.
B. Teflon
4973.
C. PE
4974.
D. Polystyrene
4975.
4976.

4977.
4978.
4979.
4980.
28. What is the dielectric constant of polyethylene (PE) insulator?
4981.
A. 2.5
4982.
B. 3.3
4983.
C. 2.27
4984.
D. 2.1
4985.
4986.
29. Polytetrafluoroethylene (PTFE) is also widely used insulator and is known as.
4987.
A. polystyrene
4988.
B. teflon
4989.
C. ceramic
4990.
D. bakelite
4991.
4992.
30. What is the characteristic impedance of a two-wire line with the following
data: diameter = 0.023in., spacing =0.5 in., insulation = PE.?
4993.
A. 300Ω
4994.
B. 250Ω
4995.
C. 305Ω
4996.
D. 301Ω
4997.
4998.
31. What is the characteristic impedance of a coaxial line with the following data:
inner diameter = 0.2 in., center conductor diameter = 0.06 in., insulation = Teflon.
4999.
A. 200Ω
5000.
B. 75Ω
5001.
C. 50Ω
5002.
D. 150Ω
5003.
5004.
32. A pair of current-carrying conductors is not considered a transmission line
unless it is at least ___ λ long at the signal frequency.
5005.
A. 0.1
5006.
B. 0.3
5007.
C. 0.2
5008.
D. 0.4
5009.
5010.
33. If the operating frequency is 450 MHz what length of a pair of conductors is
considered to be a transmission line?
5011.
A. 2.19 ft
5012.
B. 2.19 m
5013.
C. 0.219 ft
5014.
D. 0.219 m
5015.
5016.
34. What is the physical length of the above transmission line at 3/8λ long?
5017.
A.0.82 m
5018.
B. 0.82 ft

5019.
C. 0.82 in
5020.
D. 0.82 cm
5021.
5022.
35. Which of the following coaxial cable connectors is called the UHF connector?
5023.
A. PL-259
5024.
B. BNC
5025.
C. N-type connector
5026.
D. F connector
5027.
5028.
36. What connector is popular in attaching test instruments like oscilloscopes,
frequency counters, spectrum analyzers, etc?
5029.
A. UHF connector
5030.
B. PL-259
5031.
C. BNC
5032.
D. SMA
5033.
5034.
37. Which coaxial cable connector is least expensive and is widely used for TV
sets,VCRs and cable TV?
5035.
A. N-type connector
5036.
B. F-type connector
5037.
C. BNC
5038.
D. PL-259
5039.
5040.
38. Which coaxial connector is a more complex and expensive but do a better job
in maintaining the electrical characteristics of the cable through the interconnections?
5041.
A. N-type connector
5042.
B. F-type connector
5043.
C.BNC
5044.
D. PL-259
5045.
5046.
39. The velocity factor in transmission lines vary from ___ to ___.
5047.
A. 0.6 to 0.8
5048.
B. 0.3 to 0.5
5049.
C.0.5 to 0.9
5050.
D. 0.8 to 0.9
5051.
5052.
40. What is the typical velocity factor of coaxial cables?
5053.
A. 0.6 to 0.8
5054.
B. 0.3 to 0.5
5055.
C. 0.5 to 0.9
5056.
D. 0.4 to 0.6
5057.
5058.
41. What is the typical velocity factor of open-wire line?
5059.
A. 0.9
5060.
B. 0.8
5061.
C. 0.5

5062.
D. 0.7
5063.
5064.
5065.
42. What line has a typical velocity factor of about 0.8?
5066.
A. Shielded pair
5067.
B. Flexible coaxial
5068.
C. Twin-lead
5069.
D. Open-wire line
5070.
5071.
43. What is the velocity factor of coaxial cable with a characteristic impedance of
50Ω and capacitance of 30pF/ft and inductance of 75 nH/ft?
5072.
A. 0.58
5073.
B.0.68
5074.
C. 0.98
5075.
D. 0.81
5076.
5077.
44. What is transit time (time delay) of a 50-ft length transmission line of the
above problem?
5078.
A. 50 ns
5079.
B. 100 ns
5080.
C. 75 ns
5081.
D. 65 ns
5082.
5083.
45. What do you call a transmission line used specifically for the purpose of
achieving delay?
5084.
A. Delay line
5085.
B. Flat line
5086.
C. Resonant line
5087.
D. Non-resonant line
5088.
5089.
46. What is the time delay introduced by a 75-ft coaxial cable with a dielectric
constant of 2.3?
5090.
A. 1.54 ns
5091.
B. 11.5 ns
5092.
C. 115.6 ns
5093.
D. 1156 ns
5094.
5095.
47. Assume a frequency of 4 MHz, determine the phase shift offered by the line in
the above problem.
5096.
A. 108.5Ëš
5097.
B. 106.5Ëš
5098.
C. 115.5Ëš
5099.
D. 166.5Ëš
5100.
5101.
48. Find the load impedance that must be used to terminate RG-62A/U to avoid
reflections?

5102.
A. 93Ω
5103.
B. 75Ω
5104.
C. 50Ω
5105.
D. 300Ω
5106.
5107.
5108.
5109.
49. Find the equivalent inductance per foot of the above cable?
5110.
A. 13.5 nF/ft
5111.
B. 13.5 pF/ft
5112.
C. 116.8 nH/ft
5113.
D. 116.8 pF/ft
5114.
5115.
50. An RG-11/U foam coaxial cable has a maximum voltage standing wave of 52
V and a minimum voltage of 17 V. Find the value of the resistive load.
5116.
A. 24.59Ω
5117.
B. Either A or C
5118.
C. 228.75Ω
5119.
D. Neither A nor C
5120.
5121.
51. Sound provides all sorts of information. What information is related to mental
processes of knowledge, reasoning, memory, judgement and perception?
5122.
A. Cognitive
5123.
B. Affective
5124.
C. Digital
5125.
D. Analog
5126.
5127.
52. What sound characteristic relates to a sonic time pattern?
5128.
A. Tempo
5129.
B. Attack
5130.
C. Rhythm
5131.
D. Timbre
5132.
5133.
53. What is considered the most obvious conveyor of information?
5134.
A. Sound
5135.
B. Speech
5136.
C. Music
5137.
D. Noise
5138.
5139.
54. Attack is a sound characteristic that refers to the way a sound begins. Which
of the following is NOT an attack of sound?
5140.
A. Hard
5141.
B. Soft
5142.
C. Crisp
5143.
D. Simple
5144.

5145.
55. At what loudness level do pitch (in mels) and frequency (in Hz) are
numerically equal?
5146.
A. 0 dB
5147.
B. 20 dB
5148.
C. 60 dB
5149.
D. 40 dB
5150.
5151.
5152.
56. The basic voice band has how many octaves?
5153.
A. 10
5154.
B. 4
5155.
C. 5
5156.
D. 3
5157.
5158.
57. The ratio of frequencies is termed.
5159.
A. interval
5160.
B. octave
5161.
C. harmonics
5162.
D. factor
5163.
5164.
58. What is the tonal ratio of an octave?
5165.
A. 1 to 2
5166.
B. 1 to 3
5167.
C. 2 to 1
5168.
D. 3 to 1
5169.
5170.
59. If the loudness level is 100 phons, what is this in sone unit?
5171.
A. 100
5172.
B. 90
5173.
C. 106
5174.
D. 96
5175.
5176.
60. What octave bands are there in the midrange?
5177.
A. 1st and 2nd
5178.
B. 5th, 6th and 7th
5179.
C. 3rd and 4th
5180.
D. 8th and 9th
5181.
5182.
61. How much louder is 80 phons over 60 phons?
5183.
A. 1000 times
5184.
B.4 times louder
5185.
C. 100 times
5186.
D. Twice as loud
5187.
5188.
62. What increase in sound level is commonly perceived by most people?
5189.
A. 6 to 10 dB

5190.
B. 1 to 3 dB
5191.
C. 3 to 6 dB
5192.
D. 10 to 20dB
5193.
5194.
5195.
5196.
5197.
5198.
63. What is typical loudness level of an acoustic guitar 1 foot away?
5199.
A. 60dB
5200.
B. 100dB
5201.
C. 80dB
5202.
D. 40dB
5203.
5204.
64. What do you call the perceptible sound repetition?
5205.
A. Reverberation
5206.
B. Echo
5207.
C. Reflection
5208.
D. Masking
5209.
5210.
65. What is the amount of sound reduction provided by a barrier – wall, floor, or
ceiling called?
5211.
A. Sound Attenuation
5212.
B. Transmission loss
5213.
C. Sound absorption
5214.
D. Barrier loss
5215.
5216.
66. What is the frequency of a 2-cm sound wave in sea water at 25ËšC?
5217.
A. 76 kHz
5218.
B. 76 Hz
5219.
C. 76 MHz
5220.
D. 76 mHz
5221.
5222.
67. A choir consisting of 36 individuals all of whom can sing with the same
intensity. A soloist sings a certain passage and then is joined by the remainder of the choir
members for a repeat of the passage. What is the difference in the sound intensity level in
the two cases?
5223.
A. 3 dB
5224.
B. 6 dB
5225.
C. 36 dB
5226.
D. 15.6dB
5227.
5228.
68. For the safety and comfort of factory workers, the sound-intensity level in a
certain factory must remain below 85 dB. What is the maximum sound intensity allowed
in this factory?
5229.
A. 3.2 x 10-4 W/m2

5230.
5231.
5232.
5233.
5234.
5235.

B. 3.2 x 10-6 W/m2
C. 3.2 x 10-10 W/m2
D. 3.2 x 10-3 W/m2
69. What sound intensity corresponds to a sound-intensity level of 50dB?
A. 1 x 10-6W/m2
B. 1 x 10-7W/m2
C. 1 x 10-8W/m2
D.1 x 10-5W/m2

5236.
5237.
5238.
5239.
5240.
70. The sound intensity received from the nearby jet plane is 12.6 µW/m2 and that
from another jet plane some distance away is 0.45 µW/m2. Find the relative loudness of
the two.
5241.
A. 14.0 dB
5242.
B. 14.5dB
5243.
C. 12.5
5244.
D. 14.5
5245.
5246.
71. The noise from an airplane engine 100 ft from an observer is found to have an
intensity of 45dB. What will be the intensity when the plane flies overhead at an altitude
of 1 mi?
5247.
A. 10.5 dB
5248.
B. 34.5 dB
5249.
C. 35 dB
5250.
D. 20.5 dB
5251.
5252.
72. What is the apparent loudness of 80 dB?
5253.
A. Moderate
5254.
B. Very loud
5255.
C. Loud
5256.
D. Deafening
5257.
5258.
73. What loudness level in which permanent damage to hearing is possible?
5259.
A. 120 dB
5260.
B. 140 dB
5261.
C. 130 dB
5262.
D. 150 dB
5263.
5264.
74. What is sound pressure level if the RMS sound pressure is 100 μbars?
5265.
A. 114 dB
5266.
B. 11.4 dB
5267.
C. 94 dB
5268.
D. 57 dB
5269.
5270.
75. What is the velocity of sound in wood (m/s)?
5271.
A. 330

5272.
B. 3600
5273.
C. 3300
5274.
D. 5800
5275.
5276.
76. What is the optimum reverberation time at 500 to 1000 Hz of an auditorium?
5277.
A. 0.9 to 1.1 s
5278.
B. 1.4 to 1.6 s
5279.
C. 1.5 to 1.6 s
5280.
D. 1.6 to 1.8 s
5281.
5282.
5283.
5284.
77. For a cinema, the optimum volume per person required is
5285.
A. 3.1
5286.
B. 2.8
5287.
C. 7.1
5288.
D. 4.2
5289.
5290.
78. Which of the following is NOT an acoustical defect to be avoided in
acoustical designs?
5291.
A. Reverberation
5292.
B. Flutter echo
5293.
C. Distortion
5294.
D. Sound concentration
5295.
5296.
79. What absorber in which efficient absorption is only possible over a very
narrow band approaching 1.0 (total absorption)?
5297.
A. Porous material
5298.
B. Helmholtz resonator
5299.
C. Panel Absorber
5300.
D. Membrane absorber
5301.
5302.
80. How many voice signals (4 kHz max.) would fit into a 5 MHz spectrum?
5303.
A. 1250
5304.
B. 500
5305.
C. 1000
5306.
D. 1500
5307.
5308.
81. How many FM stations would be accommodated I an ordinary TV channel?
5309.
A. 33
5310.
B. 30
5311.
C. 40
5312.
D. 25
5313.
5314.
82. What is the actual length in feet of a one-quarter wavelength of a coax with a
velocity factor of 0.695 at 45 MHz?

5315.
A. 17.82
5316.
B. 19.26
5317.
C. 16.28
5318.
D. 16.97
5319.
5320.
83. Determine the terrain sensitivity loss for a 4-GHz carrier that is propagating
over a very dry, mountainous area.
5321.
A. -1.25 dB
5322.
B. -3.05 dB
5323.
C. -2.01 dB
5324.
D. -5.01 dB
5325.
5326.
5327.
84. A satellite transmitter operates at 4GHz with an antenna gain of 4dBi. The
receiver 40000 km away has an antenna gain of 50 dBi. If the transmitter has a power of
8 W, find (ignoring feedline losses and mismatch) the EIRP in dBW.
5328.
A. 50
5329.
B. 69
5330.
C. 49
5331.
D. 30
5332.
5333.
85. A radio signal moves from air to glass. The angle of incidence is 20°.
Calculate the angle of refraction. The relative permittivity of the glass is 7.8.
5334.
A. 7.8°
5335.
B. 5.04°
5336.
C. 6.04°
5337.
D. 7.04°
5338.
5339.
86. At a certain time, the MUF for transmission at an angle of incidence of 75° is
17 MHz. What is the critical frequency?
5340.
A. 4.4 MHz
5341.
B. 3.5 MHz
5342.
C. 6.5 MHz
5343.
D. 1.5 MHz
5344.
5345.
87. A properly matched transmission line has a loss of 1.5 dB/100m. if 10 W is
supplied to one end of the line, how many watts reach the load, 27 m away?
5346.
A. 10 W
5347.
B. 7.2 W
5348.
C. 9.9 W
5349.
D. 9.1 W
5350.
5351.
88. The electromagnetic radiation theory was profounded by
5352.
A. Sir Edward Appleton
5353.
B. Guglielmo Marconi
5354.
C. Heinrich Hertz

5355.
D. James C. Maxwell
5356.
5357.
89. What is caused by the transverse nature of electromagnetic waves?
5358.
A. Polarization
5359.
B. Interference
5360.
C. Beamwidth
5361.
D. Gain
5362.
5363.
90. Which propagation method is known as special case of skywave?
5364.
A. Space wave
5365.
B. Troposcatter
5366.
C. Ground wave
5367.
D. Direct wave
5368.
91. What is the orbit inclination of geostationary satellites?
5369.
A. 0°
5370.
B. 10°
5371.
C. 20°
5372.
D. 30°
5373.
5374.
92. A transmission line of unknown impedance is terminated with two different
resistances, and an SWR is measured each time. With a 75 Ω termination, the SWR
measures 1.5. With a 300 Ω termination, it measures 2.67. What is the impedance of the
line?
5375.
A. 100 Ω
5376.
B. 212 Ω
5377.
C. 300 Ω
5378.
D. 112 Ω
5379.
5380.
93. What is the high frequency sound that cannot be heard by the human ear?
5381.
A. Ultrasonic
5382.
B. Transonic
5383.
C. Subsonic
5384.
D. Supersonic
5385.
5386.
94. What frequency is 10 octaves above 30 Hz?
5387.
A. 30.72 kHz
5388.
B. 30 kHz
5389.
C. 300 Hz
5390.
D. 307.2 kHz
5391.
5392.
95. A radio signal travels ____ yards per microseconds.
5393.
A. 273
5394.
B. 328
5395.
C. 618
5396.
D. 123.6
5397.

5398.
96. What is the actual length in feet of a one-half wavelength of a coax with a
velocity factor of 0.63 at 28 MHz?
5399.
A. 44.28
5400.
B. 43.46
5401.
C. 11.07
5402.
D. 46.27
5403.
5404.
97. The range of speech power is ____.
5405.
A. 1 – 10 watts
5406.
B. 100 – 1000 milliwatts
5407.
C. 10 – 100 milliwatts
5408.
D. 10 – 1000 microwatts
5409.
5410.
98. What is the actual length in feet of a one-quarter wavelength of a coax with a
velocity factor of 0.68 to 30 MHz?
5411.
A. 19.26
5412.
B. 5.6
5413.
C. 17.82
5414.
D. 16.97
5415.
5416.
99. What is actual length in feet of a one-half wavelength of a coax with a
velocity factor of 0.59 at 26 MHz?
5417.
A. 11.16
5418.
B. 40.29
5419.
C. 42.46
5420.
D. 46.28
5421.
5422.
100. The agreed standard for measuring loudness is the loudness sensation
produced by a 1000 Hz sine wave _____ dB above the listener’s threshold of hearing.
5423.
A. 80
5424.
B. 50
5425.
C. 30
5426.
D. 40
5427.
5428.
5429.
5430.
5431.
5432.
5433.
5434.
5435.
5436.
5437.
5438.
5439.

5440.
5441.
5442.
5443.
5444.
5445.
5446.
5447.
5448.
5449.
5450.
5451.
5452.
5453.
Test Yourself – Exam 08
5454.
5455. What is the refractive index of an ionospheric layer with 100x105 free electrons per m3?
5456.
Assume frequency to be at 20 MHz.
5457.
A. 0.99
5458.
B. 0.15
5459.
C. 0.78
5460.
D. 0.85
5461.
5462.
2. “Each point on a spherical wavefront may be considered a source of secondary
spherical wavefronts”. This is known as the
5463. A. Snell’s law
5464.
B. D’Alembert’s principle
5465.
C. Appleton’s theory
5466.
D. Huygen’s principle
5467.
5468.
3. What is meant by the term deviation ratio?
5469.
A. The ratio of the audio modulating frequency to the center carrier
frequency.
5470.
B. The ratio of the maximum carrier frequency deviation to the
highest audio modulating frequency.
5471.
C. The ratio of the carrier center frequency to the audio modulating
frequency.
5472.
D. The ratio of the highest audio modulating frequency to the average
audio modulating frequency.
5473.
5474.
4. What is the major cause of selective fading?
5475.
A. Small changes in the beam heading at the receiving station.
5476.
B. Large changes in the height of the ionosphere, as experience at the
receiving station.
5477.
C. Time differences between the receiving and transmitting stations.
5478.
D. Phase differences between radio wave components of the same
transmission, as experienced at the receiving station.

5479.
5480.
5. What phenomenon causes the radio-path horizon distance to exceed the
geometric horizon?
5481.
A. E-layer skip.
5482.
B. D-layer skip.
5483.
C. Auroral skip.
5484.
D. Radio waves may be bent.
5485.
5486.
6. What propagation condition is usually indicated when a VHF signal is received
from a station over 500 miles away?
5487.
A. D-layer absorption
5488.
B. Faraday rotation
5489.
C. Tropospheric ducting
5490.
D. Moonbounce
5491.
5492.
7. What is meant by the term modulation index?
5493.
A. The processor index.
5494.
B. The ratio between the deviation of a frequency modulated signal
and the modulating frequency.
5495.
C. The FM signal-to-noise ratio.
5496.
D. The ratio of the maximum carrier frequency deviation to the highest
audio modulating frequency.
5497.
5498.
8. The bending of radio waves passing over the top of a mountain range that
disperses a weak portion of the signal behind the mountain is
5499.
A. eddy-current phase effect
5500.
B. knife-edge diffraction
5501.
C. shadowing
5502.
D. mirror refraction effect
5503.
5504.
9. What is the wavelength of a signal at 500 MHz?
5505.
A. 0.062 cm
5506.
B. 6 meters
5507.
C. 60 cm
5508.
D. 60 meters
5509.
5510.
10. What is included in the total resistance of an antenna system?
5511.
A. Radiation resistance plus space impedance
5512.
B. Radiation resistance plus transmission resistance
5513.
C. Transmission line resistance plus radiation resistance
5514.
D. Radiation resistance plus ohmic resistance
5515.
11. What are electromagnetic waves?
5516.
A. Alternating currents in the core of an electromagnet
5517.
B. A wave consisting of two electric fields at right angles to each other
5518.
C. A wave consisting of an electric field and a magnetic field at right
angles to each other

5519.
D. A wave consisting of two magnetic fields at right angles to each other
5520.
5521.
12. The band of frequencies least susceptible to atmospheric noise and
interference is:
5522.
A. 30 – 300 kHz
5523.
B. 300 – 3000 kHz
5524.
C. 3 – 30 MHz
5525.
D. 300 – 3000 MHz
5526.
5527.
13. What is the relationship in degrees of the electrostatic and electromagnetic
fields of an antenna?
5528.
A. 0 degree
5529.
B. 45 degrees
5530.
C. 90 degrees
5531.
D. 180 degrees
5532.
5533.
14. For a space wave transmission, the radio horizon distance of a transmitting
antenna with a height of 100 meters is approximately:
5534.
A. 10 km
5535.
B. 40 km
5536.
C. 100 km
5537.
D. 400 km
5538.
5539.
15. What is meant by referring to electromagnetic waves as horizontally
polarized?
5540.
A. The electric field is parallel to the earth.
5541.
B. The magnetic field is parallel to the earth.
5542.
C. Both the electric and magnetic fields are horizontal
5543.
D. Both the electric and magnetic fields are vertical
5544.
5545.
16. What is meant by referring to electromagnetic waves as having circular
polarization?
5546.
A. The electric field is bent into a circular shape.
5547.
B. The electric field rotates
5548.
C. The electromagnetic wave continues to circle the earth
5549.
D. The electromagnetic wave has been generated by a quad antenna
5550.
5551.
17. If a transmitting antenna is 100 meters high and a separate receiving antenna
is 64 meters high, what is the maximum space wave communication distance possible
between them?
5552.
A. 18 km
5553.
B. 72 km
5554.
C. 164 km
5555.
D. 656 km
5556.

5557.
18. A receiver is located 64 km from a space wave transmitting antenna that is 100
meters high. Find the required height of the receiving antenna.
5558.
A. 36 meters high
5559.
B. 64 meters high
5560.
C. 100 meters high
5561.
D. 182.25 meters high
5562.
5563.
19. Which of the following is not one of the natural ways a radio wave may travel
from transmitter to receiver?
5564.
A. Ground wave
5565.
B. Micro wave
5566.
C. Sky wave
5567.
D. Space wave
5568.
5569.
20. Which of the following terrain types permits a ground wave to travel the
farthest?
5570.
A. Salt water
5571.
B. Fresh water
5572.
C. Sandy
5573.
D. Rocky
5574.
5575.
21. What is the input terminal impedance at the center if a folded dipole antenna?
5576.
A. 300 ohms
5577.
B. 72 ohms
5578.
C. 50 ohms
5579.
D. 450 ohms
5580.
5581.
22. What is the term used to describe a spread spectrum communications system
where the center frequency if a conventional carrier is altered many time per second in
accordance with a pseudo-random list of channels?
5582.
A. Frequency hopping
5583.
B. Direct sequence
5584.
C. Time-domain frequency modulation
5585.
D. Frequency compandored spread spectrum
5586.
5587.
23. What is the velocity factor for non-foam dielectric 50 or 75 ohm flexible
coaxial cable such as RG 8, 11, 58 and 59?
5588.
A. 2.70
5589.
B. 0.66
5590.
C. 0.30
5591.
D. 0.10
5592.
5593.
5594.
5595.
5596.

5597.
24. If a transmission line has a power loss of 6 dB per 100 feet, what is the power
at the feed point to the antenna at the end of a 200 foot transmission line fed by a 100
watt transmitter?
5598.
A. 70 watts
5599.
B. 50 watts
5600.
C. 25 watts
5601.
D. 6 watts
5602.
5603.
25. What determines the velocity factor in a transmission line?
5604.
A. The termination impedance
5605.
B. The line length
5606.
C. Dielectrics in the line
5607.
D. The center conductor resistivity
5608.
5609.
26. What term is used to describe a spread spectrum communications system in
which a very fast binary bit stream is used to shift the phase of an RF carrier?
5610.
A. Frequency hopping
5611.
B. Direct sequence
5612.
C. Binary phase-shift keying
5613.
D. Phase compandored spread spectrum
5614.
5615.
27. Which of the following frequency bands is best suited for ground wave
propagation?
5616.
A. 30 to 300 kHz
5617.
B. 300 kHz to 3 MHz
5618.
C. 3 MHz to 30 MHz
5619.
D. 30 MHz to 300 MHz
5620.
5621.
28. Which of the following frequency bands is best suited for sky wave
propagation?
5622.
A. 30 to 300 kHz
5623.
B. 3 MHz to 30 MHz
5624.
C. 30 MHz to 300 MHz
5625.
D. 3 GHz to 30 GHz
5626.
5627.
29. What is the seventh harmonic of a 100 MHz quarter wavelength antenna?
5628.
A. 14.28 MHz
5629.
B. 107 MHz
5630.
C. 149 MHz
5631.
D. 700 MHz
5632.
5633.
30. Which if the following layers of the ionosphere has no effect on sky wave
propagation during the hours of darkness?
5634.
A. D
5635.
B. E
C. F1
5636.

5637.

D. F2

5638.
5639.
31. Skip distance can be maximized by using the ____ radiation angle possible
and the ____ frequency that will be refracted at that angle.
5640.
A. lowest, lowest
5641.
B. lowest, highest
5642.
C. highest, lowest
5643.
D. highest, highest
5644.
5645.
32. What is the meaning of the term “velocity factor” of a transmission line?
5646.
A. The ratio of the characteristic impedance of the line to the terminating
impedance
5647.
B. The index of shielding for coaxial cable.
5648.
C. The velocity of the wave on the transmission line multiplied by the
velocity of light in a vacuum.
5649.
D. The velocity of the wave on the transmission line divided by the
velocity of light in a vacuum.
5650.
5651.
33. What is the term for the ratio of actual velocity at which a signal travels
through a line to the speed of light in a vacuum?
5652.
A. Velocity factor
5653.
B. Characteristic impedance
5654.
C. Surge impedance
5655.
D. Standing wave ratio
5656.
5657.
34. Why is the physical length of a coaxial cable transmission line shorter than its
electrical length?
5658.
A. Skin effect is less pronounced in the coaxial cable
5659.
B. RF energy moves slower along the coaxial cable
5660.
C. The surge impedance is higher in the parallel feed line
5661.
D. The characteristic impedance is higher in the parallel feed line
5662.
5663.
35. What would be the physical length of a tpical coaxial transmission line that is
electrically one-quarter wavelength long at 14.1 MHz?
5664.
A. 20 meters
5665.
B. 3.51 meters
5666.
C. 2.33 meters
5667.
D. 0.25 meter
5668.
5669.
36. To obtain the most reliable sky wave propagation the ____ should be used.
5670.
A. Lowest useable frequency (LUF).
5671.
B. Maximum useable frequency (MUF).
5672.
C. Optimum useable frequency (OUF).
5673.
D. Critical frequency
5674.
5675.

5676.
5677.
5678.
37. What is the deviation ratio for an FM-phone signal having a maximum
frequency swing of plus or minus 5 kHz and accepting a maximum modulation rate of
3kHz?
5679.
A. 60
5680.
B. 0.16
5681.
C. 0.6
5682.
D. 1.66
5683.
5684.
38. Tropospheric scatter is a method of sky wave propagation for which of the
following frequency bands?
5685.
A. 300 kHz to 3 MHz
5686.
B. 3 MHz to 30 MHz
5687.
C. 30 MHz to 300 MHz
5688.
D. 300 MHz to 3 GHz
5689.
5690.
39. What is the frequency range of an aircraft’s radio altimeter?
5691.
A. 962 MHz to 1213 MHz
5692.
B. 329.15 MHz to 335.00 MHz
5693.
C. 4250 MHz to 4350 MHz
5694.
D. 108.00 MHz to 117.95 MHz
5695.
5696.
40. What type of transmission is radiated from an aircraft’s radio altimeter
antenna?
5697.
A. An amplitude modulated continuous wave
5698.
B. A pulse position modulated UHF signal
5699.
C. A differential phase shift keyed UHF signal
5700.
D. A frequency modulated continuous wave
5701.
5702.
41. The polarization of a radio wave:
5703.
A. Is perpendicular to the electrostatic field of the antenna
5704.
B. Is the same direction as the electrostatic field of the antenna.
5705.
C. Is the same direction as the magnetic field of the antenna.
5706.
D. Is perpendicular to both the electrostatic and magnetic fields of the
antenna.
5707.
5708.
42. A coaxial cable has 7dB of reflected power when the input is 5 watts. What is
the output of the transmission line?
5709.
A. 5 watts
5710.
B. 2.5 watts
5711.
C. 1.25 watts
5712.
D. 1 watt
5713.
5714.
43. When is it useful to refer to an isotropic radiator?
5715.
A. When comparing the gains of directional antennas

5716.
B. When testing a transmission line for standing wave ratio
5717.
C. When (in the northern hemisphere) directing the transmission in a
southerly direction
5718.
D. When using a dummy load to tune a transmitter
5719.
5720.
44. Most AM broadcasts employ ___ polarization while most FM broadcasts
employ ___ polarization of the radio wave.
5721.
A. vertical, vertical
5722.
B. vertical, horizontal
5723.
C. horizontal, vertical
5724.
D. horizontal, horizontal
5725.
5726.
45. How does the gain of a parabolic dish type antenna change when the operating
frequency is doubled?
5727.
A. Gain does not change
5728.
B. Gain is multiplied by 0.707
5729.
C. Gain increases 6 dB
5730.
D. Gain increases 3 dB
5731.
5732.
46. What is the frequency range of an aircraft’s Very High Frequency (VHF)
communications?
5733.
A. 118.000 MHz to 136.975 MHz (worldwide up to 151.975 MHz)
5734.
B. 108.000 MHz to 117.95 MHz
5735.
C. 329.15 MHz to 335.00 MHz
5736.
D. 2.0000 MHz to 29.999 MHz
5737.
5738.
47. What is a selective fading effect?
5739.
A. A fading effect caused by small changes in beam heading at the
receiving station.
5740.
B. A fading effect caused by phase differences between radio wave
components of the same transmission, as experienced at the receiving station.
5741.
C. A fading effect caused by large changes in the height of the ionosphere,
as experienced at the receiving station
5742.
D. A fading effect caused by time differences between the receiving and
transmitting stations.
5743.
5744.
48. If the velocity of propagation in a certain medium is 200x106 m/s, what is its
refractive index?
5745.
A. 1.3
5746.
B. 1.5
5747.
C. 1.27
5748.
D. 0.67
5749.
5750.
49. What is the resultant field strength at the receiving antenna in space wave
propagation under case 2?
5751.
A. 0

5752.
B. ξd
5753.
C. 2ξd
5754.
D. 3ξd
5755.
5756.
5757.
5758.
5759.
50. The decimetric wave is using what method of propagation?
5760.
A. Ground wave
5761.
B. Space wave
5762.
C. Sky wave
5763.
D. Tropospheric wave
5764.
5765.
51. What is the typical frequency used for communicating to submerged
submarines?
5766.
A. 100 Hz
5767.
B. 500 Hz
5768.
C. 4 kHz
5769.
D. 200 Hz
5770.
5771.
52. Which frequency bands can be refracted during the day by the D layer?
5772.
A. VLF
5773.
B. MF
5774.
C. LF
5775.
D. Both VLF and LF
5776.
5777.
53. What height of an ionized layer is determined from the time interval between
the transmitted signal and the ionospheric echo at vertical incidence?
5778.
A. Virtual height
5779.
B. Apparent height
5780.
C. Actual height
5781.
D. Effective height
5782.
5783.
54. During the night when the F2 layer combines with F1 layer it falls to what
approximate height?
5784.
A. 250 km
5785.
B. 350 km
5786.
C. 300 km
5787.
D. 400 km
5788.
5789.
55. Which of the following is considered the most frequently used transmission
line?
5790.
A. Two-wire open line
5791.
B. Twin lead
5792.
C. Rigid coaxial line
5793.
D. Flexible coaxial line

5794.
5795.
56. The antenna effective height is ____ to ____ of the actual height.
5796.
A. ½ to 2/3
5797.
B. ½ to ¾
5798.
C. ¼ to 2/3
5799.
D. ¼ to ¾
5800.
5801.
5802.
57. What is the propagation velocity of a signal in a transmission line whose
inductance and capacitance are 5μH/m and 20μF/m respectively?
5803.
A. 100x103 m/s
5804.
B. 100 m/s
5805.
C. 10x103 m/s
5806.
D. 100x106 m/s
5807.
5808.
58. What is the phase coefficient in radians per unit length of a transmission line
at the frequency of 10 MHz if the velocity of propagation is 2.5x108 m/s?
5809.
A. 0.25
5810.
B. 2.5
5811.
C. 0.35
5812.
D. 3.5
5813.
5814.
59. Determine the conductance of a two-wire open line with the following
parameters: D = 4 in., d = 0.1 in. and ρ = 2.6x108 Ω-m.
5815.
A. 2.76x10-9 S/m
5816.
B. 2.76x10-6 S/m
5817.
C. 2.76x10-12 S/m
5818.
D. 2.76x10-3 S/m
5819.
5820.
60. What is the input impedance of a transmission line if its characteristic
impedance is 300 Ω and the load is 600 Ω? Assume a quarter wavelength section only.
5821.
A. 150 kΩ
5822.
B. 150 mΩ
5823.
C. 150 Ω
5824.
D. 2 Ω
5825.
5826.
61. Determine the standing wave ratio of a 300-Ω line whose load is 400+j150 Ω.
5827.
A. 3.55
5828.
B. 1.67
5829.
C. 5.53
5830.
D. 3.35
5831.
5832.
62. What is the optimum volume per person of rooms for speech?
5833.
A. 2.8
5834.
B. 3.1
5835.
C. 4.2

5836.
D. 5.1
5837.
5838.
63. What happens to the beamwidth of an antenna as the gain is increased?
5839.
A. The beamwidth increases geometrically as the gain is increased.
5840.
B. The beamwidth increases arithmetically as the gain is increased.
5841.
C. The beamwidth is essentially unaffected by the gain of the antenna.
5842.
D. The beamwidth decreases as the gain is increased.
5843.
5844.
64. A superhet receiver has an IF of 455 kHz and is experiencing image-channel
interference on a frequency of 1570 kHz. The receiver is tuned to
5845.
A. 1115 kHz
5846.
B. 660 kHz
5847.
C. 2025 kHz
5848.
D. 910 kHz
5849.
5850.
65. What is the end impedance of a half-wave dipole?
5851.
A. 73 Ω
5852.
B. 72 Ω
5853.
C. 250 Ω
5854.
D. 2500 Ω
5855.
5856.
66. What volume of the chamber is required to measure absorption coefficient at
100 Hz?
5857.
A. 125 m3
5858.
B. 50 m3
5859.
C. 150 m3
5860.
D. 352 m3
5861.
5862.
67. What is the optimum reverberation time at 500 Hz for a cinema?
5863.
A. 0.8 – 1.2 sec.
5864.
B. 0.9 – 1.3 sec.
5865.
C. 0.6 – 0.8 sec.
5866.
D. 0.45 – 0.55 sec.
5867.
5868.
68. An FM receiver whose intermediate frequency is 10.7 MHz, is experiencing
image channel interference from a station transmitting on 121.1 MHz. If the local
oscillator is tracking above, the receiver is tuned to
5869.
A. 131.8 MHz
5870.
B. 110.4 MHz
5871.
C. 142.5 MHz
5872.
D. 99.7 MHz
5873.
5874.
69. A 1 Mhz carrier is amplitude modulated by a pure 200-Hz audio test tone.
Which of the following combinations of frequencies represent the total content of the AM
signal?
5875.
A. 1 MHz and 200 Hz

5876.
B. 1 MHz and 1000.2 kHz
5877.
C. 999.8 kHz, 1000 kHz, and 1000.2 kHz
5878.
D. 999.8 kHz and 1000.2 kHz
5879.
5880.
70. What establishes the receiver bandwidth?
5881.
A. RF amplifier
5882.
B. Mixer
5883.
C. Local oscillator
5884.
D. IF amplifier
5885.
5886.
71. What noise type is observable between 8 MHz to somewhat above 1.43 GHz
or up to 1.5 GHz?
5887.
A. Solar noise
5888.
B. Space noise
5889.
C. Galactic noise
5890.
D. Cosmic noise
5891.
5892.
72. Flicker noise is a poorly understood form of noise which may be completely
ignored about above ____.
5893.
A.100 Hz
5894.
B. 200 Hz
5895.
C. 400 Hz
5896.
D. 500 Hz
5897.
5898.
73. What is the typical gain of a rhombic antenna?
5899.
A. Between 15 to 60
5900.
B. Between 20 to 90
5901.
C. Between 50 to 75
5902.
D. Between 10 to 25
5903.
5904.
74. What illumination factor is normally considered in computing parabolic
antenna gain in microwave communications?
5905.
A. 0.54
5906.
B. 0.65
5907.
C. 0.75
5908.
D. 0.85
5909.
5910.
75. How many voice band channels are there in a superjumbo group?
5911.
A. 600
5912.
B. 900
5913.
C. 10,800
5914.
D. 3,600
5915.
5916.
76. In acoustics, what is the reference pressure in lb/ft2 unit?
5917.
A. 2x10-5
5918.
B. 0.0002

5919.
C. 2.089
5920.
D. 2.980
5921.
5922.
77. Which of the following characterizes a properly terminated transmission line?
5923.
A. The line loss is minimum.
5924.
B. The standing wave ratio is minimum.
5925.
C. The input impedance is twice the load impedance.
5926.
D. The standing wave ratio is one.
5927.
5928.
5929.
78. What is the meaning of forward power?
5930.
A. The power traveling from the transmitter to the antenna.
5931.
B. The power radiated from the top of an antenna system.
5932.
C. The power produced during the positive half of an RF cycle.
5933.
D. The power used to drive a linear amplifier.
5934.
5935.
79. What organization has published safety guidelines for the maximum limits of
RF energy near the human body?
5936.
A. The American National Standards Institute (ANSI).
5937.
B. The Environmental Protection Agency (EPA).
5938.
C. The Federal Communications Commission (FCC).
5939.
D. The Institute Of Electrical and Electronics Engineers (IEEE).
5940.
5941.
80. When no signal is being received, the loudspeaker is not entirely silent as a
result of the presence of
5942.
A. parasitic oscillations in some of the receiver stages.
5943.
B. negative feedback in each stage.
5944.
C. spurious frequencies as a result of improper neutralization.
5945.
D. internal receiver noise.
5946.
5947.
81. When measuring a transmitter’s frequency against a suitable standard, the
frequency to be measured is taken from the
5948.
A. oscillator stage
5949.
B. intermediate amplifier
5950.
C. buffer stage
5951.
D. final RF stage
5952.
5953.
82. When the is the ionosphere most ionized?
5954.
A. Dusk
5955.
B. Midnight
5956.
C. Dawn
5957.
D. Midday
5958.
5959.
83. Cellular radios use FM with a maximum deviation of
5960.
A. ±30 kHz

5962.

B. ±75 kHz
C. ±25 kHz

5963.

D. ±12 kHz

5961.

5964.
5965.
84. What device measures the angle between two radio frequencies and also the
direction of propagation of a wave?
5966.
A. Densimeter
5967.
B. Absorption wavemeter
5968.
C. Goniometer
5969.
D. Ergometer
5970.
5971.
85. An automated ship-to-shore distress alerting system using satellites and
advanced terrestrial communications systems.
5972.
A. GPS
5973.
B. Iridium system
5974.
C. INMARSAT
5975.
D. GMDSS
5976.
5977.
86. What antenna can be used to minimize the effect of Faraday rotation of
polarization?
5978.
A. Dipole
5979.
B. Parabolic
5980.
C. Helical
5981.
D. Rhombic
5982.
5983.
87. The presence of standing waves on a transmission line is the result of
5984.
A. a high level of attenuation on the line.
5985.
B. terminating the line by a resistive load equal in value to the surge
impedance
5986.
C. reducing the input power to below its critical level.
5987.
D. an impedance mismatch between the load and the line.
5988.
5989.
88. What device measures rf power by measuring the heat the rf power generates?
5990.
A. Calorimeter
5991.
B. Goniometer
5992.
C. Spectrum meter
5993.
D. Oscilloscope
5994.
5995.
89. What is considered the most efficient mode in terms of energy transfer in
waveguides?
5996.
A. Dominant mode
5997.
B. Normal mode
5998.
C. Conventional mode
5999.
D. Vertical mode

6000.
6001.
90. In acoustics, _____ is the apparent change in frequency or pitch when a sound
source moves either toward or away from a listener.
6002.
A. flanking
6003.
B. reverberation
6004.
C. Doppler effect
6005.
D. echo
6006.
6007.
91. Which of the following wavelengths where absorption of electromagnetic
waves becomes peak due to vibrational resonances in the water vapor molecule?
6008.
A. 1.35 cm and 1.7 mm
6009.
B. 1.5 mm and 5mm
6010.
C. 1.35 dm and 1.7cm
6011.
D. 1.5 cm and 5 mm
6012.
6013.
6014.
92. Oxygen molecule absorption peaks to electromagnetic wave are at what
wavelengths?
6015.
A. 1.35 mm and 1.7 μm
6016.
B. 1.35 cm and 1.7 mm
6017.
C. 5 cm and 2.5 cm
6018.
D. 5 mm and 2.5 mm
6019.
6020.
93. The approximate single-hop nighttime range of F2 layer is ____.
6021.
A. 3000 km
6022.
B. 3840 km
6023.
C. 4130 km
6024.
D. 2350km
6025.
6026.
94. What ionospheric layer has a daytime approximate critical frequency of 8
MHz?
6027.
A. F2 layer
6028.
B. F1 layer
6029.
C. E layer
6030.
D. D layer
6031.
6032.
95. In cellular system, _____ defines the geographic distance that is required
between cells using identical frequencies in order to avoid interference between the radio
transmissions at these cells.
6033.
A. frequency-reuse ratio
6034.
B. distance-to-reuse ratio (D/R)
6035.
C. reuse format plan ratio
6036.
D. reuse factor
6037.
6038.
96. What do you call the ability of a mobile phone to change from one channel
(frequency) to another?

6039.
A. Frequency agility
6040.
B. Frequency handoff
6041.
C. Frequency handover
6042.
D. Frequency switch
6043.
6044.
97. What mathematical plane figure is ideal in cellular system design and
engineering it graphically and functionally depicts overlapping radio coverage between
and among adjacent cell base stations?
6045.
A. Hexagon
6046.
B. Octagon
6047.
C. Pentagon
6048.
D. Nonagon
6049.
6050.
98. In cellular system, the average lead time to install a new base station is
approximately ____ months to a year.
6051.
A. 4
6052.
B. 5
6053.
C. 6
6054.
D. 10
6055.
99. What is considered the threshold of audibility at 3000 Hz?
6056.
A. 10-12 W/m2
6057.
B. 10-16 W/m2
6058.
C. 10-12 W/cm2
6059.
D. 10-15 W/cm2
6060.
6061.
100. At one atmospheric pressure, what is the approximate speed of sound in
steel?
6062.
A. 5150 m/s
6063.
B. 5150 ft/s
6064.
C. 4990 m/s
6065.
D. 4990 ft/s
6066.
6067.
6068.
6069.
6070.
6071.
6072.
6073.
6074.
6075.
6076.
6077.
6078.
6079.
6080.
Test Yourself – Exam 09

6081.
6082.
1. What significant element of sound refers to its characteristic tonal quality?
6083.
A. Pitch
6084.
B. Tempo
6085.
C. Rhythm
6086.
D. Timbre
6087.
6088.
2. What is the velocity of sound in wood?
6089.
A. 5800 m/s
6090.
B. 5000 m/s
6091.
C. 3300 m/s
6092.
D. 3700 m/s
6093.
6094.
3. What is the typical loudness level of a watch ticking?
6095.
A. 0 phon
6096.
B. 40 phons
6097.
C. 20 phons
6098.
D. 60 phons
6099.
6100.
4. The typical length of the rhombic antenna is ____.
6101.
A. 2λ to 8λ
6102.
B. 10λ to 20λ
6103.
C. 1λ to 3λ
6104.
D. 5λ to 10λ
6105.
6106.
5. What is the carrier frequency of supergroup 10?
6107.
A. 2724 kHz
6108.
B. 2356 kHz
6109.
C. 2108 kHz
6110.
D. 3100 kHz
6111.
6112.
6113.
6. In SPADE system, how many PCM-encoded voice band channels are there?
6114.
A. 800
6115.
B. 600
6116.
C. 300
6117.
D. 240
6118.
6119.
7. The product of the radiated RF power of a transmitter and the gain of the
antenna system in a given direction relative to an isotropic radiator is called ____.
6120.
A. Effective Radiated Power (ERP)
6121.
B. Effective Isotropic Radiated Power (EIRP)
6122.
C. Radiated Power
6123.
D. Transmit Power
6124.

6125.
8. The product of antenna input power and the antenna power gain expressed in
kW is called __.
6126.
A. Effective Radiated Power (ERP)
6127.
B. Effective Isotropic Radiated Power (EIRP)
6128.
C. Radiated Power
6129.
D. Transmit Power
6130.
6131.
9. What satellite system parameter represents the quality of a satellite or an earth
station receiver?
6132.
A. Gain-to-Equivalent Noise Temperature Ratio (G/Te)
6133.
B. Energy of Bit-to-Noise Density Ratio (Eb/No)
6134.
C. Carrier-to-Noise Density Ratio (C/No)
6135.
D. Bit energy
6136.
6137.
10. What noise is observable at frequencies in the range from about 8 MHz to
somewhat 1.5 GHz?
6138.
A. Industrial noise
6139.
B. Atmospheric noise
6140.
C. Space noise
6141.
D. Shot noise
6142.
6143.
11. A special horn antenna consisting of a parabolic cylinder joined to a pyramidal
horn.
6144.
A. Hoghorn
6145.
B. Cass-horn
6146.
C. Pyramidal horn
6147.
D. Conical horn
6148.
6149.
12. How many telegraph channels are there in the basic voice band channels?
6150.
A. 24
6151.
B. 96
6152.
C. 48
6153.
D. 672
6154.
6155.
6156.
13. Which of the following is oldest multiplexing scheme?
6157.
A. Frequency Division Multiplexing (FDM)
6158.
B. Time Division Multiplexing (TDM)
6159.
C. Code Division Multiplexing (CDM)
6160.
D. Space Division Multiplexing (SDM)
6161.
6162.
14. What carrier system multiplexes 96 voice band channels into a single 6.312
Mbps data signal?
6163.
A. T1 carrier system
6164.
B. T2 carrier system
6165.
C. T1C carrier system

6166.
D. T3 carrier system
6167.
6168.
15. What is the metric subdivision of VHF band?
6169.
A. Metric
6170.
B. Millimetric
6171.
C. Decimetric
6172.
D. Centimetric
6173.
6174.
16. In satellite communications, what means of attitude control is using the
angular momentum of the spinning body to provide the roll and yaw stabilization?
6175.
A. Spin stabilization
6176.
B. Radial stabilization
6177.
C. Three-axis stabilization
6178.
D. Station keeping
6179.
6180.
17. Which of the following is NOT a porous absorber?
6181.
A. Prefabricated tiles
6182.
B. Plasters and spray on materials
6183.
C. Acoustic blankets
6184.
D. Membrane absorber
6185.
6186.
18. What historical satellite broadcasted live the 1964 Olympic games from
Tokyo, Japan for the first time?
6187.
A. Syncom I
6188.
B. Syncom III
6189.
C. Syncom II
6190.
D. Syncom IV
6191.
6192.
19. In transmission line, which of the following is the first step in the procedure of
using stub matching?
6193.
A. Calculate stub susceptance.
6194.
B. Calculate load admittance
6195.
C. Connect stub to load
6196.
D. Transform conductance to resistance
6197.
6198.
20. What type of balun (balanced-to-unbalanced) is used in high frequency
applications?
6199.
A. Transformer type balun
6200.
B. A specially configured coaxial transmission line
6201.
C. A specially configured parallel-wire line
6202.
D. A λ/2 transformer balun
6203.
6204.
21. ____ is defined as any radiation of energy by means of electromagnetic wave.
6205.
A. Emission
6206.
B. Radiation
6207.
C. Radio

6208.
D. Broadcasting
6209.
6210.
22. In what year did Hertz discover radio waves?
6211.
A. 1844
6212.
B. 1873
6213.
C. 1887
6214.
D. 1895
6215.
6216.
23. Which of the following phenomena is possible is free space medium?
6217.
A. Reflection of radio wave
6218.
B. Diffraction of radio wave
6219.
C. Refraction of radio wave
6220.
D. Attenuation of radio wave
6221.
6222.
24. What is the reactance property at the input of a shorted quarter wavelength
line?
6223.
A. A parallel LC circuit
6224.
B. A pure inductive reactance
6225.
C. A series LC circuit
6226.
D. A pure capacitive reactance
6227.
6228.
25. An early satellite owned by US Department of Defense that lasted only for 17
days
6229.
A. Courier
6230.
B. Echo
6231.
C. Score
6232.
D. Westar 1
6233.
6234.
26. Which of the following is the consolidation of H. No. 5224 and S. No. 2683?
6235.
A. RA 9292
6236.
B. RA 5734
6237.
C. RA 7925
6238.
D. RA 6849
6239.
6240.
6241.
6242.
6243.
6244.
27. Who will appoint the chairman and 2 members of the board of Electronics
Engineering?
6245.
A. The Senate President
6246.
B. The President
6247.
C. The Supreme Court
6248.
D. The Commission on Appointment
6249.

6250.
28. How many nominees per position of the Electronics Engineering Board are
nominated by IECEP to PRC?
6251.
A. 3
6252.
B. 5
6253.
C. 4
6254.
D. 6
6255.
6256.
29. According to RA 9292, how many days after the board exam the results will
be released?
6257.
A. Within 5 days
6258.
B. Within 15 days
6259.
C. Within 20 days
6260.
D. Within 3 days
6261.
6262.
30. How many removal examination (s) will be given to an examinee who obtains
a passing rating in the majority of the subjects but obtains a rating in the other subject (s)
below seventy percent (70%) but not lower than sixty percent (60%)?
6263.
A. 1
6264.
B. 3
6265.
C. 2
6266.
D. Unlimited
6267.
6268.
31. Which of the following determines the acoustic behavior of gases?
6269.
A. Density
6270.
B. Pressure
6271.
C. Temperature
6272.
D. All of the choices
6273.
6274.
32. In what medium sound travels the faster?
6275.
A. Vacuum
6276.
B. Solid
6277.
C. Liquid
6278.
D. Gas
6279.
6280.
33. For a loudness level between 110 and 120 dB, the maximum daily exposure
limit is ____ minute (s).
6281.
A. 1
6282.
B. 60
6283.
C. 20
6284.
D. 45
6285.
6286.
34. A porous material is far more efficient at high than low frequency absorption.
How to improve sound absorption at lower frequencies using this absorber?
6287.
A. Increase the thickness
6288.
B. Decrease the thickness
6289.
C. Mount with and airspace behind

6290.
D. Both A and C above
6291.
6292.
35. Which of the following describes a TDM frame?
6293.
A. A 250-μs frame
6294.
B. A 125-μs frame
6295.
C. A 500-μs frame
6296.
D. A 60-μs frame
6297.
6298.
36. ____ system transmits frequency-division-multiplexed voice band signals
over a coaxial cable for distances up to 4000 miles.
6299.
A. T carrier
6300.
B. X carrier
6301.
C. L carrier
6302.
D. F carrier
6303.
6304.
37. What is the spectrum range of U600 mastergroup?
6305.
A. 60 – 108 kHz
6306.
B. 564 – 3084 kHz
6307.
C. 312 – 552 kHz
6308.
D. 60 -2788 kHz
6309.
6310.
38. Which frequency reuse method is less effective because of Faraday’s effect?
6311.
A. Dual polarization
6312.
B. Reducing antenna beamwidth
6313.
C. Zonal rotation
6314.
D. Spin stabilization
6315.
6316.
39. Three telephone circuits, each having an S/N ratio of 44 dB, are connected in
tandem. What is the overall S/N ratio?
6317.
A. 44 dB
6318.
B. 39.2 dB
6319.
C. 41 dB
6320.
D. 43.52 dB
6321.
6322.
40. What is the noise factor if the equivalent noise temperature is 25 K?
6323.
A. 1.09
6324.
B. 0.09
6325.
C. 0.36 dBm
6326.
D. 0.36
6327.
6328.
6329.
41. A ground station is operating to a geostationary satellite at a 5° angle of
elevation. Calculate the round-trip time between ground station and satellite.
6330.
A. 275 s
6331.
B. 275 ms
6332.
C. 137.5 s

6333.
D. 137.5 ms
6334.
6335.
42. Calculate the reverberation time of a living room 8 ft high, 13 ft wide and 20
ft long. The total absorption of the building structure inside the room is 180.7 sabines
with four persons present in the room.
6336.
A. 0.5 ms
6337.
B. 0.05 s
6338.
C. 0.5 s
6339.
D. 5 ms
6340.
6341.
43. What is the number of levels required in a PCM system with S/N ratio of 40
dB?
6342.
A. 64
6343.
B. 128
6344.
C. 256
6345.
D. 512
6346.
6347.
44. A radio communications link is to be established via the ionosphere. The
maximum virtual height of the layer is 100 km at the midpoint of the path and the critical
frequency is 2 MHz. The distance between stations is 600 km. determine the optimum
working frequency?
6348.
A. 6.32 MHz
6349.
B. 2.1 MHz
6350.
C. 5.4 MHz
6351.
D. 1.8 MHz
6352.
6353.
45. Part of a microwave link can be approximated by free space conditions. The
antenna gain are each 40 dB, the frequency is 10 GHz, and the path length is 80 km.
Calculate the receive power for a transmitted power of 10 W?
6354.
A. 0.871 μW
6355.
B. 871 μW
6356.
C. 0.871 mW
6357.
D. 871 nW
6358.
6359.
46. What is the approximate critical frequency of the E layer?
6360.
A. 4 MHz
6361.
B. 5 MHz
6362.
C. 6 MHz
6363.
D. 3 MHz
6364.
6365.
6366.
6367.
6368.
47. What is the approximate single-hop nighttime range of F2 layer?
6369.
A. 3840 km
6370.
B. 3000 km

6371.
C. 4130 km
6372.
D. 2350 km
6373.
6374.
48. What ionospheric layer has a daytime approximate critical frequency of 8
MHz?
6375.
A. F2 layer
6376.
B. F1 layer
6377.
C. E layer
6378.
D. D layer
6379.
6380.
49. Determine the additional absorption (sabines) contributed by 10 persons in a
room.
6381.
A. 47
6382.
B. 4.7
6383.
C. 0.47
6384.
D. 470
6385.
6386.
50. A frequency of 3000 Hz has how many octaves above 1000 Hz?
6387.
A. 1.6 octaves
6388.
B. 2.1 octaves
6389.
C. 1 octave
6390.
D. 3 octaves
6391.
6392.
51. The loudness level increased from 40 to 56 phons. What is the increase in
loudness sensation?
6393.
A. 3 times
6394.
B. 4.5 times
6395.
C. 2 times
6396.
D. 4 times
6397.
6398.
52. In the North American TDM system, what is the transmission rate in Mbps of
T3 carrier system?
6399.
A. 44.736
6400.
B. 6.312
6401.
C. 3.152
6402.
D. 274.176
6403.
6404.
53. What is the data rate in Mbps of a single satellite transponder considering an
S/N of 30 dB?
6405.
A. 35.8
6406.
B. 3.58
6407.
C. 358
6408.
D. 3580
6409.
6410.

6411.
54. What condition occur when the refractive index of the air decreases with
height much more rapidly the normal?
6412.
A. Refraction
6413.
B. Superrefraction
6414.
C. Subrefraction
6415.
D. Diffraction
6416.
6417.
55. What do you call the increase of temperature with height?
6418.
A. Temperature inversion
6419.
B. Normal inversion
6420.
C. Ducting
6421.
D. Superrefraction
6422.
6423.
56. ____ is a term given to the region where superrefraction occurs.
6424.
A. Strata
6425.
B. Duct
6426.
C. Isothermal region
6427.
D. Tropospheric region
6428.
6429.
57. Which of the following wavelengths where absorption of electromagnetic
waves becomes peak due to vibrational resonances in the water vapor molecule?
6430.
A. 1.35 cm and 1.7 mm
6431.
B. 1.5 mm and 5 mm
6432.
C. 1.35 dm and 1.7 cm
6433.
D. 1.5 cm and 5mm
6434.
6435.
58. Oxygen molecule absorption peaks to electromagnetic wave are at what
wavelengths?
6436.
A. 1.35 cm and 1.7 mm
6437.
B. 5 mm and 2.5 mm
6438.
C. 5 cm and 2.5 cm
6439.
D. 1.35 mm and 1.7 μm
6440.
6441.
59. What instrument normally measures the virtual height of ionosphere?
6442.
A. Ionosonde
6443.
B. Altimeter
6444.
C. Field meter
6445.
D. Radar
6446.
6447.
60. The angle of elevation of the antenna beam is 20°. Calculate the transmissionpath distance for an ionospheric transmission that utilizes a layer of virtual height 200
km. Use flat-earth approximation.
6448.
A. 966 km
6449.
B. 2100 km
6450.
C. 1100 km
6451.
D. 405 km

6452.
6453.
61. If temperature change is 19°C, what amount of change to sound velocity is
possible?
6454.
A. 11.53 ft/s
6455.
B. 11.53 m/s
6456.
C. 19.304 ft/s
6457.
D. 19.304 m/s
6458.
6459.
62. In the above problem, what is the new velocity of sound assuming dry air
medium?
6460.
A. 343 ft/s
6461.
B. 3430 m/s
6462.
C. 343 m/s
6463.
D. 342 m/s
6464.
6465.
63. In acoustics, if the volume of the room is 200 m3 then at what frequency the
coefficient of absorption is measured?
6466.
A. 120 kHz
6467.
B. 120 Hz
6468.
C. 100 Hz
6469.
D. 150 Hz
6470.
6471.
64. What is the approximate bandwidth of an FM system with 10 kHz of
modulating frequency and a 150 kHz of frequency deviation?
6472.
A. 300 kHz
6473.
B. 320 kHz
6474.
C. 150 kHz
6475.
D. 200 kHz
6476.
6477.
65. Which of the following layers of the ionosphere has no effect on sky wave
propagation during daytime?
6478.
A. D
6479.
B. E
6480.
C. F1
6481.
D. F2
6482.
6483.
66. What phenomenon causes the radio-path horizon distance to exceed the
geometric horizon?
6484.
A. Diffraction
6485.
B. Ducting
6486.
C. Reflection
6487.
D. Refraction
6488.
6489.
67. How to maximize the skip distance?
6490.
A. Using the smallest possible radiation angle and highest possible
frequency

6491.
B. Using the smallest possible radiation angle and lowest possible
frequency
6492.
C. Using the biggest possible radiation angle and highest possible
frequency
6493.
D. Using the biggest possible radiation angle and lowest possible
frequency
6494.
6495.
68. For a space wave transmission, the radio horizon distance of a receiving
antenna with a height of 64 meters is approximately
6496.
A. 8 km
6497.
B. 32 km
6498.
C. 64 km
6499.
D. 256 km
6500.
6501.
69. What bandwidth is needed to support a capacity of 128 kbps when the signal
power to noise power ratio in decibels is 100?
6502.
A. 19224 Hz
6503.
B. 3853 Hz
6504.
C. 19244 Hz
6505.
D. 3583 Hz
6506.
6507.
70. Which of the following systems uses frequency band 870-885 MHz as a
transmit band of its base station?
6508.
A. TACS
6509.
B. NTT
6510.
C. NMT
6511.
D. AMPS
6512.
6513.
71. A transmitted signal 5 meters in wavelength is received by an antenna coil
having a 50-Ω resistance and a 0.01 H inductance. What is the capacitance of the tuner
shunting the antenna coil at this point?
6514.
A. 0.704 fF
6515.
B. 0.704 μF
6516.
C. 0.704 nF
6517.
D. 0.704 mF
6518.
6519.
72. Which of the following is the basic component of a communications satellite
receiver?
6520.
A. On-board computer
6521.
B. Reflector
6522.
C. Telemetry
6523.
D. Transponder
6524.
6525.
73. The reverberation time of a 184.2 cubic meters broadcast studio is 0.84 sec.
Find the absorption effect of the materials used in metric sabines.
6526.
A. 35.3

6527.
B. 10.96
6528.
C. 379.8
6529.
D. 109.6
6530.
6531.
6532.
6533.
6534.
6535.
74. What is the highest frequency that can be sent straight upward and be returned
to earth?
6536.
A. MUF
6537.
B. Gyro frequency
6538.
C. Skip frequency
6539.
D. Critical frequency
6540.
6541.
75. What is the most important specification of loudspeakers and microphones?
6542.
A. Frequency response
6543.
B. Power density
6544.
C. Field Strength
6545.
D. Gain
6546.
6547.
76. Atmospheric attenuation is an attenuation which is due to
6548.
A. mist and fog
6549.
B. gasses in the atmosphere
6550.
C. water vapor and oxygen
6551.
D. rain
6552.
6553.
77. Satellite orbits around the earth are ____ orbits.
6554.
A. circular
6555.
B. either elliptical or circular
6556.
C. elliptical
6557.
D. circular only
6558.
6559.
78. How does spatial isolation technique in satellite communications avoid
interference?
6560.
A. Use of different polarity antennas
6561.
B. Use of different types of antennas
6562.
C. Employment of highly directional spot-beam antennas
6563.
D. Use of low gain antennas
6564.
6565.
79. An area on earth covered by a satellite radio beam is called ____.
6566.
A. SSP
6567.
B. Region
6568.
C. footprint
6569.
D. primary area
6570.

6571.
80. The American concert pitch A is equivalent to which if the following
frequencies?
6572.
A. 440 Hz
6573.
B. 435 Hz
6574.
C. 260 Hz
6575.
D. 255 Hz
6576.
6577.
6578.
6579.
6580.
6581.
81. The international pitch A is equivalent to ___ Hz.
6582.
A. 435
6583.
B. 440
6584.
C. 260
6585.
D. 255
6586.
6587.
82. The speed of the satellite increases as its height in orbit gets
6588.
A. lower
6589.
B. higher
6590.
C. closer to the moon
6591.
D. closer to the sun
6592.
6593.
83. What is the effective radiated power of a repeater with 50 watts transmitter
power output \, 4 dB feedline loss, 3 dB duplexer and circulator loss, and 6 dB antenna
gain?
6594.
A. 158 W
6595.
B. 39.7 W
6596.
C. 251 W
6597.
D. 69.9 W
6598.
6599.
84. A cellular standard known as the cdmaOne.
6600.
A. IS-95
6601.
B. IS-136
6602.
C. IS-54
6603.
D. IS-100
6604.
6605.
85. What is the effective radiated power of a repeater with 50 watts transmitter
power output, 5 dB feedline loss, 4 dB duplexer and circulator loss, and 7 dB antenna
gain?
6606.
A. 300 W
6607.
B. 315 W
6608.
C. 31.5 W
6609.
D. 69.9 W
6610.
6611.
86. Which Ethernet system is restricted only to 100 m?

6612.
A. 10 Base T
6613.
B. 20 Base 2
6614.
C. 10 Base 5
6615.
D. 10 Base 1
6616.
6617.
87. What is the effective radiated power of a repeater with 75 watts transmitter
power output, 4 dB feedline loss, 3 dB duplexer and circulator loss, and 10 dB antenna
gain?
6618.
A. 600 W
6619.
B. 75 W
6620.
C. 18.75 W
6621.
D. 150 W
6622.
6623.
88. Which of the following regulates the ownership and operation of radio and
television stations in the country?
6624.
A. PD 576-A
6625.
B. PD 756
6626.
C. PD 657
6627.
D. PD 677
6628.
6629.
89. What is the effective radiated power of a repeater with 75 watts transmitter
power output, 5 dB feedline loss, 4 dB duplexer and circulator loss, and 6 dB antenna
gain?
6630.
A. 37.6 W
6631.
B. 237 W
6632.
C. 150 W
6633.
D. 23.7 W
6634.
6635.
90. In GSM cellular system, the speech coding rate is ____.
6636.
A. 13 kbps
6637.
B. 8 kbps
6638.
C. 15 kbps
6639.
D. 20 kbps
6640.
6641.
91. What is the effective radiated power of a repeater with 100 watts transmitter
power output, 5 dB feedline loss, 4 dB duplexer and circulator loss, and 10 dB antenna
gain?
6642.
A. 800 W
6643.
B. 126 W
6644.
C. 12.5 W
6645.
D. 1260 W
6646.
6647.
92. Which NTC memorandum circular governs the rules and regulations about the
manufacture, acquisition, sale and service of radio communication equipment?
6648.
A. MC No. 2-05-88
6649.
B. MC No. 2-04-88

6650.
C. MC No. 2-07-88
6651.
D. MC No. 2-09-88
6652.
6653.
93. What is the effective radiated power of a repeater with 120 watts transmitter
power output, 5 dB feedline loss, 4 dB duplexer and circulator loss, and 6 dB antenna
gain?
6654.
A. 601 W
6655.
B. 240 W
6656.
C. 60 W
6657.
D. 379 W
6658.
6659.
94. What do you call a short bit sequence sent typically 128 bits in digital
signatures?
6660.
A. Hash
6661.
B. Public key
6662.
C. Private key
6663.
D. Password
6664.
95. What medium is used by IBM token ring network that operates at either 4
Mbps or 16 Mbps?
6665.
A. Twisted pair
6666.
B. Coaxial cable
6667.
C. Fiber-optic
6668.
D. Parallel-wire line
6669.
6670.
96. What is known as the final stage in the evolution of the GSM standard?
6671.
A. WAP
6672.
B. GPRS
6673.
C. EDGE
6674.
D. Bluetooth
6675.
6676.
97. According to KBP revised radio code which airtime below is classified class
D for AM stations?
6677.
A. 6:00 AM to 12:00 NN
6678.
B. 12:00 NN to 6:00 PM
6679.
C. 9:00 PM to 12 Midnight
6680.
D. 12:00 Midnight to 5:00 AM
6681.
6682.
98. Encryption of data is important to ensure its privacy. It is most commonly
achieved by using a ____.
6683.
A. public-key encryption
6684.
B. private-key encryption
6685.
C. password-key encryption
6686.
D. character set encryption
6687.
6688.
99. The speech coding rate in D-AMPS is ____.
6689.
A. 8 kbps

6690.
B. 13 kbps
6691.
C. 15 kbps
6692.
D. 20 kbps
6693.
6694.
100. Which of the following principal musical intervals is considered dissonant?
6695.
A. 7:8
6696.
B. 1:2
6697.
C. 5:8
6698.
D. 3:5
6699.
6700.
6701.
6702.
6703.
6704.
6705.
6706.
6707.
6708.
6709.
6710.
6711.
6712.
6713.
Test Yourself – Exam 10
6714.
________ is a standard whereby mobile phones can gain access to specially
tailored Internet websites.
6715. Bluetooth
6716. GPRS
6717. WAP
6718. EDGE
6719.
6720.
What noise is a transient short-duration disturbance distributed essentially
uniformly over the useful passband of a transmission system?
6721. Flicker noise
6722. Transit-time noise
6723. Shot noise
6724. Impulse noise
6725.
6726.
What is the insertion loss of connector type splices for a single mode optical
fiber?
6727. 0.51 dB
6728. 0.49 dB
6729. 0.31 dB
6730. 0.38 db
6731.
6732.
In the European standard, the aurial transmitter maximum radiated power is

______ of peak visual transmitter power.
6733. 10%
6734. 30%
6735. 20%
6736. 40%
6737.
6738.
What is the common up-converter and down-converter IF for microwave
communications?
6739. 60 MHz
6740. 80 MHz
6741. 120 MHz
6742. 70 MHz
6743.
6744.
What is the data link protocol that is used in asynchronous transmission for
transferring files from one computer to another?
6745. A modem
6746. X modem
6747. B modem
6748. C modem
6749.
6750.
What distortion is not caused by transmission line characteristics?
6751. Phase distortion
6752. Pulse shape distortion
6753. Spacing bias distortion
6754. Amplitude distortion
6755.
6756.
What is the effective radiated power of a repeater with 200 watts transmitter
power output, 4 dB feline loss, 4 dB duplexer and circulator loss, and 10 dB antenna
gain?
6757. 317 W
6758. 2000 W
6759. 126 W
6760. 260 W
6761.
6762.
Which of the following is standardized as part of GSM phase 2+ that can offer
theoretical data speeds of upto 115 kbit/s?
6763. EDGE
6764. GPRS
6765. WAP
6766. Bluetooth
6767.
6768.
A ______ is essentially a cell site that is mounted on a flatbed tractor-trailer used
for emergency purposes.
6769. COW
6770. BULL
6771. CALF

6772. PONY
6773.
6774.
Which of the following best describes a dip-meter?
6775. An SWR meter
6776. A counter
6777. A variable LC oscillator with metered feedback current
6778. A field strength meter
6779.
6780.
Which is space diversity system?
6781. Two or more antennas operating on two different frequencies?
6782. Two transmitters operating at same frequencies
6783. Two or more antennas operating on the same frequency
6784. Two antennas from two different transmitters
6785.
6786.
What part or section of a TV receiver that separates the sound and video signals?
6787. IF stage
6788. Video amplifier
6789. Video detector
6790. Burst separator
6791.
6792.
What is the channel number of an FM station with a carrier frequency of 99.5
MHz?
6793. 256
6794. 258
6795. 257
6796. 259
6797.
6798.
In a triple conversion superheterodyne receiver, diode mixer stages are operated
6799. In the linear region
6800. In the nonlinear region
6801. As class A amplifiers
6802. As class B amplifiers
6803.
6804.
In ISDN, what is the basic access B channel data rate?
6805. 32 kbps
6806. 64 kbps
6807. 144 kbps
6808. 16 kbps
6809.
6810.
What is the channel spacing for MF-HF voice frequencies?
6811. 2.8 kHz
6812. 500 Hz
6813. 3.5 kHz
6814. 3 kHz
6815.
6816.
What is the quantization signal-to-noise ratio if an 8-bit PCM code is used?

6817. 40 dB
6818. 50 dB
6819. 60 dB
6820. 65 dB
6821.
6822.
What is the emission designation of a single sideband reduced carrier signal?
6823. H3E
6824. J3E
6825. R3E
6826. B8E
6827.
6828.
What is the most commonly used intermediate frequency of radar receivers?
6829. 40 MHz
6830. 60 MHz
6831. 70 MHz
6832. 30 MHz
6833.
6834.
The input signal of a travelling wave tube is introduced at
6835. Cathode
6836. Anode
6837. Cathode end of the helix
6838. Collector end of the helix
6839.
6840.
What determines the ability of radar to determine the bearing to a target?
6841. Speed of light
6842. Speed of target
6843. Antenna directivity
6844. Frequency of signal
6845.
6846.
What is the minimum number of bits required in a PCM code for a range of
10,000?
6847. 12
6848. 9
6849. 14
6850. 10
6851.
6852.
The antenna current is doubled when the modulation index is doubled in ______
AM system.
6853. A5C
6854. A3J
6855. A3
6856. A3H
6857.
6858.
Which of the following is not a bounded medium?
6859. Coaxial line
6860. Two-wire line

6861. Waveguide
6862. Free space
6863.
6864.
What is affected by the distance between the listener and the source of the sound
because the intensity varies inversely with the square of the distance?
6865. Volume
6866. Pitch
6867. Loudness
6868. Frequency
6869.
6870.
Comparing the capacities of a DVD and an ordinary CD, DVD is ______ time
bigger than CD.
6871. 10
6872. 20
6873. 15
6874. 25
6875.
6876.
Locking on to a defined target is known as
6877. Homing
6878. Referencing
6879. Searching
6880. Defining
6881.
6882.
What causes the maximum usable frequency to vary?
6883. The temperature of the ionosphere
6884. The speed of the winds in the upper atmosphere
6885. The type of weather just below the ionosphere
6886. The amount of radiation received from the sun
6887.
6888.
What limits the sensitivity of a receiver?
6889. The power supply of the receiver
6890. The power output of a transmitter
6891. The noise floor of the receiver
6892. The distance between the transmitter and receiver
6893.
6894.
What is the standard test tone used for audio measurements?
6895. 100 Hz
6896. 500 Hz
6897. 1000 Hz
6898. 2000 Hz
6899.
6900.
What causes image interference?
6901. Low gain
6902. High IF
6903. Poor front-end selectivity
6904. Low signal-to-noise ratio

6905.
6906.
What frequency band is referred to as the metric waves?
6907. VHF
6908. UHF
6909. HF
6910. SHF
6911.
6912.
A waveguide passive component that brings a smooth change in the direction of
axis maintained perpendicular to the plane of polarization?
6913. L bend
6914. H bend
6915. T bend
6916. X bend
6917.
6918.
How far is the visual carrier from the lowest frequency in the spectrum of a
monochrome TV broadcast channel following the NTSC standard?
6919. 1.5 MHz
6920. 1.25 MHz
6921. 4.5 MHz
6922. 0.25 MHz
6923.
6924.
What aircraft deviation is measured by an ILS localizer?
6925. Altitude
6926. Ground speed
6927. Vertical
6928. Horizontal
6929.
6930.
Skip zone is otherwise known as
6931. Empty zone
6932. Shadow zone
6933. Null zone
6934. Zone of silence
6935.
6936.
In the American standard, the aural transmitter maximum radiated power is _____
of peak visual transmitter power.
6937. 10 %
6938. 30 %
6939. 20 %
6940. 40 %
6941.
6942.
What character signifies the start of the test for Bisync?
6943. STX
6944. SOH
6945. BCC
6946. ETX
6947.

6948.
A low frequency audible periodic variation in pitch of sound output in high
fidelity sound reproduction system?
6949. Flutter
6950. Wow
6951. String vibration
6952. Radio sound
6953.
6954.
When can a corporation or association incorporated under the Philippine laws and
with foreign investors be granted radio station license?
6955. When 60% of the capital is owned by Filipino citizens
6956. When 50% of the capital is owned by Filipino citizens
6957. When the chairman of the board is a Filipino
6958. When the president of the corporation/association is a Filipino
6959.
6960.
______ is a term in the test language for noise testing in telephone circuits that
means a one-syllable word consisting of a consonant, a vowel, and another consonant.
6961. Logatom
6962. Nosfer
6963. Ore
6964. Belcore
6965.
6966.
Why are frequency modulation transmitters more efficient?
6967. Because their power is increased by class C amplifiers
6968. Because their power is increased by class A amplifiers
6969. Because their power is increased by class B amplifiers
6970. Because their power is increased by class AB amplifiers
6971.
6972.
A 1000W carrier is amplitude modulated to a depth of 85%. Calculate the total
power of the modulated wave?
6973. 1361.25 W
6974. 680.62 W
6975. 1425 W
6976. 712.5 W
6977.
6978.
Which is not an ITU sector?
6979. ITU-W
6980. ITU-R
6981. ITU-T
6982. ITU-D
6983.
6984.
What is the process of cancelling the effect on internal device capacitance in radio
transmitters?
6985. Degaussing
6986. Neutralization
6987. Ionization
6988. Stabilization

6989.
6990.
Which of the following is the basic synthesizer circuit?
6991. Frequency divider
6992. Frequency multiplier
6993. PLL
6994. Mixer
6995.
6996.
Which one is not an important characteristic of the physical layer?
6997. Electrical
6998. Logical
6999. Mechanical
7000. All of the choices
7001.
7002.
What is the typical separation between the two conductors in a parallel wire line?
7003. 0.001 to 0.01 m
7004. 200 to 500 mm
7005. 0.635 to 15.24 cm
7006. 2.5 to 5 in.
7007.
7008.
In t-carrier system, t3 has a bit rate of
7009. 560.160 Mbps
7010. 44.376 Mbps
7011. 44.736 Mbps
7012. 560.106 Mbps
7013.
7014.
In radio signal emission designation, the fifth symbol means
7015. Details of signals
7016. Type of information transmitted
7017. Nature of multiplexing
7018. Nature of signal modulating the main carrier
7019.
7020.
What is the channel spacing for SITOR frequencies?
7021. 500 Hz
7022. 170 Hz
7023. 300 Hz
7024. 3 kHz
7025.
7026.
Which of the following is the new name of CCITT?
7027. ITU-T
7028. ITU-R
7029. ITU-S
7030. ITU-D
7031.
7032.
Which of the following frequencies is normally used for distress and safety
communications?
7033. 4209.5 kHz

7034. 490 kHz
7035. 518 kHz
7036. 2174.5 kHz
7037.
7038.
What is the difference between available power and power budget?
7039. Power margin
7040. Extra power
7041. Fade margin
7042. System gain
7043.
7044.
A matched termination in which the electromagnetic energy is absorbed by water.
7045. Maximum power transfer
7046. Load
7047. Load water
7048. Basin
7049.
7050.
What do you call the electrical conduction in a photosensitive material which is
not exposed to radiation?
7051. Dark conductance
7052. Pure conductance
7053. Black out
7054. Super conductance
7055.
7056.
How many sidebands are present in the J3E mode?
7057. Two sidebands and a carrier
7058. One upper sideband
7059. One lower sideband
7060. Two carriers and one sideband
7061.
7062.
A component that samples the microwave signal travelling in one direction down
to the transmission line
7063. Isolator
7064. Combiner
7065. Directional coupler
7066. Attenuator
7067.
7068.
What does OMB stand for?
7069. Optical media board
7070. Organization of medical biologist
7071. Optical medium board
7072. Optimum main board
7073.
7074.
A test method of comparing two audio systems by switching inputs so that the
same recording is heard in rapid succession over one given system and then the other.
7075. B test
7076. A test

7077. AB test
7078. C test
7079.
7080.
And ITU-T specification code that deals with the telephone circuits.
7081. X series
7082. T series
7083. V series
7084. I series
7085.
7086.
What digital carrier transmits a digital signal at 274.176 Mbps?
7087. T1
7088. T3
7089. T2
7090. T4
7091.
7092.
What signal-to-noise ratio is required for satisfactory television reception?
7093. 10 dB
7094. 30 dB
7095. 40 dB
7096. 20 dB
7097.
7098.
How many telephone channels are there in AT 2 line?
7099. 50
7100. 90
7101. 83
7102. 96
7103.
7104.
What optical source radiates light uniformly in all directions?
7105. Isotropic source
7106. Lambertian source
7107. Voltage source
7108. Ideal source
7109.
7110.
What is the spectrum of stereophonic FM signal?
7111. 19 to 38 kHz
7112. 30 to 53 kHz
7113. 59.5 to 74.5 kHz
7114. 88 to 108 MHz
7115.
7116.
What is the required quality factor for an SSB filter with the following data:
center frequency= 1 MHz, the desired attenuation level of the unwanted sideband= 80 dB
and the separation between sidebands= 200 Hz?
7117. 1,250
7118. 12,500
7119. 125,000
7120. 25,000

7121.
7122.
What do you call the reflection of a part of incident light at the interface of two
media that have different refractive indices?
7123. Snell’s reflection
7124. Fresnel reflection
7125. Lambertian reflection
7126. Huygen’s reflection
7127.
7128.
Which conference in the ITU-structure does the telecommunication
standardization bureau report?
7129. World telecommunication standardization conference
7130. ITU-development sector
7131. Radio regulation board
7132. The secretary general
7133.
7134.
What region around a broadcasting transmitter in which satisfactory reception of
broadcasting signal is not obtained?
7135. Fringe area
7136. Primary are
7137. Secondary area
7138. Tertiary area
7139.
7140.
What do you call the random noise seen on radar display screen?
7141. Impulse noise
7142. Atmospheric noise
7143. Grass
7144. Johnson noise
7145.
7146.
Which of the following antennas receives signals equally well from all directions
in a horizontal plane?
7147. Hetz antenna
7148. Vertical Marconi antenna
7149. Yagi antenna
7150. Helical antenna
7151.
7152.
Where is the brightness control located in a TV?
7153. The audio section
7154. The video section
7155. The grid-cathode circuit
7156. The front panel
7157.
7158.
What is the term used in telephony and telegraphy for irregular disturbing
radiation due to various causes and in a particular produced by arc transmitters causing a
rushing sound in receiving telephones?
7159. Fax tone
7160. Mush

7161. Hiss
7162. Crosstalk
7163.
7164.
What device in a waveguide system used for stopping or diverting
electromagnetic wave as desired?
7165. Mechanical switch
7166. Electric switch
7167. Push-button switch
7168. Waveguide switch
7169.
7170.
What is the maximum power that can be obtained from a microwave tube at 10
GHz?
7171. 500 W
7172. 10 W
7173. 50 W
7174. 20 W
7175.
7176.
What do you call a cable consisting of twisted pairs of conductors, each separately
insulated?
7177. Microstrip line
7178. Strip line
7179. Quad
7180. Coaxial cable
7181.
7182.
What mixer type has the lowest spurious signals?
7183. Double-balanced
7184. Single-balanced
7185. Super-heterodyner
7186. Heterodyner
7187.
7188.
What are the electromagnetic radiations of wavelengths less than 300 angstroms?
7189. X-rays
7190. Ultraviolet rays
7191. Infrared
7192. Microwaves
7193.
7194.
What is known as the alignment of the three color guns to a common point?
7195. Confetti
7196. Divergence
7197. Convergence
7198. Synchronization
7199.
7200.
What is the department order that governs commercial radio operator?
7201. Department Order No. 5
7202. Department Order No. 23
7203. Department Order No. 88

7204. Department Order No. 44
7205.
7206.
The computer which initiates information transfer
7207. Master
7208. Station
7209. Slave
7210. Mainframe
7211.
7212.
Which of the following antennas require good grounding?
7213. Yagi antenna
7214. Hertz antenna
7215. Marconi antenna
7216. Isotropic antenna
7217.
7218.
Which circuit detects frequency modulated signal?
7219. Modulator
7220. Discriminator
7221. Demodulator
7222. Modem
7223.
7224.
What synchronization is provided so that the start and end of message is
identified?
7225. Carrier
7226. Character
7227. Bit
7228. Clock
7229.
7230.
A form of regenerative repeater for transmitting signals over a long cable received
through a relay in a clearer form.
7231. Active generator
7232. Active repeater
7233. Interpolator
7234. Audio generator
7235.
7236.
What is the minimum propagation delay of a geostationary satellite?
7237. 278 ms
7238. 239 ms
7239. 300 ms
7240. 600 ms
7241.
7242.
In measuring crosstalk using dBx unit the reference power is
7243. 1 mW
7244. 1 W
7245. 1 pW
7246. 6 mW
7247.

7248.
A spot on the sun’s visible surface where the magnetic flux lines converge?
7249. Sunspot
7250. Filament
7251. Solar spot
7252. Prominence
7253.
7254.
______ is a slow moving large mass of plasma on the sun’s surface.
7255. Filament
7256. Solar flare
7257. Prominence
7258. Proton flare
7259.
7260.
______ is slow moving “cord-like” mass of plasma across the sun’s surface.
7261. Filament
7262. Solar flare
7263. Prominence
7264. Solar spot
7265.
7266.
At what particular wavelength is solar flux measured?
7267. 10.7 mm band
7268. 10.7 m band
7269. 10.7 cm band
7270. 10.7 nm band
7271.
7272.
What is the approximate intensity of the magnetic field at the earth’s surface?
7273. 32,000 nT
7274. 62,000 nT
7275. 32,000 µT
7276. 62,000 µT
7277.
7278.
What is the intensity of the magnetic field at the earth’s north pole?
7279. 32,000 nT
7280. 62,000 nT
7281. 32,000 µT
7282. 62,000 µT
7283.
7284.
What do you call a satellite weighing less than 1 kg?
7285. Nanosat
7286. Picosat
7287. Femtosat
7288. Microsat
7289.
7290.
The first creature in space was carried by which of the following spacecrafts in
November 3, 1957?
7291. Sputnik 1
7292. Sputnik 3

7293. Sputnik 2
7294. Explorer 1
7295.
7296.
The wireless evolution is achieved through the GSM family of wireless
technology platforms which include but except one of the following. Which one is NOT a
member of the GSM family?
7297. GSM
7298. EDGE
7299. GPRS
7300. CDMA
7301.
7302.
Which of the following is an enhancement of GSM including the GPRS?
7303. 1G
7304. 2.5G
7305. 2G
7306. 3G
7307.
7308.
A low power, short range wireless technology designed to provide a replacement
for serial cables is called ______.
7309. WAP
7310. GPRS
7311. Bluetooth
7312. EDGE
7313.
7314.
7315.
7316.
7317.
7318.
7319.
7320.
7321.
7322.
7323.
7324.
7325.
7326.
7327.
7328.
7329.
7330.
7331.
7332.
7333.
7334.

7335.
7336.
7337.
7338.
7339.
7340.
7341.
Noise Chapter 4 (3001 Questions in Communications Engineering-EXCEL
REVIEW CENTER)
7342.
What is the non-continuous noise of irregular pulses or spikes of duration with
high amplitudes?
7343. Wander
7344. Jitter
7345. Hits
7346. Singing
7347.
What theorem sets a limit on the maximum capacity of a channel with a given
noise level?
7348. Nyquist theorem
7349. Hartley law
7350. Shannon-Hartley theorem
7351. Shannon theorem
7352.
Quantizing noise occurs in
7353. PCM
7354. PLM
7355. PDM
7356. PAM
7357.
Noise always affects the signal in a communications systems at the ________.
7358. transmitter
7359. channel
7360. information source
7361. destination
7362.
_________ is the random and unpredictable electric signals from natural causes,
both internal and external to the system.
7363. Interference
7364. Attenuation
7365. Distortion
7366. Noise
7367.
Noise from random acoustic or electric noise that has equal energy per cycle over
a specified total frequency band.
7368. Gaussian noise
7369. Whiter noise
7370. Thermal noise
7371. All of the above
7372.
Which causes a quantization noise in PCM system?
7373. Serial transmission errors
7374. The approximation of the quantized signal
7375. The synchronization between encoder and decoder

7376. Binary coding techniques
7377.
A particular circuit that rids FM of noise
7378. Detector
7379. Discriminator
7380. Phase Shifter
7381. Limiter
7382.
What is the reference noise temperature in degrees Celsius?
7383. 17
7384. 273
7385. 25
7386. 30
7387.
Unwanted radio signal on assigned frequency.
7388. Splatter
7389. RFI
7390. Noise
7391. EMI
7392.
What is the reliable measurement for comparing amplifier noise characteristics?
7393.
A. Thermal agitation noise
7394.
B. Noise factor
7395.
C. Noise margin
7396.
D. Signal-to-noise
7397.
7398.
_________ is measured on a circuit when it is correctly terminated but does not
have any traffic.
7399.
White noise
7400.
Galactic noise
7401.
Impulse noise
7402.
Atmospheric noise
7403.
Which standard recommends crosstalk limits?
7404. CCIT G.152
7405. CCIT G.150
7406. CCIT G.151
7407. CCIT G.161
7408.
Which standard is utilized in intermodulation noise rates on PCM audio channels?
7409. CCIT Rec. G.151
7410. CCIT Rec. G.172
7411. CCIT Rec. G.190
7412. CCIT Rec. G.190
7413.
What is the reference frequency of CCIT phosphomeric noise measurement?
7414. 800 Hz
7415. 1000 Hz
7416. 1500 Hz
7417. 3400 Hz
7418.
Reference temperature use in noise analysis
7419. 75 K
7420. 250 K

7421. 290 K
7422. 300 K
7423.
Which noise is produced by lighting discharges in thunderstorms?
7424. White noise
7425. Extraterrestrial noise
7426. Industrial noise
7427. Atmospheric noise
7428.
Man-made noise is usually from _______.
7429. transmission over power lines and by ground wave
7430. sky-wave
7431. space-wave
7432. troposphere
7433.
nif stands for
7434. Non-intrinsic figure
7435. Noise improvement factor
7436. Narrow intermediate frequency
7437. Noise interference figure
7438.
Industrial noise frequency is between _____.
7439. 0 to 10 KHz
7440. 160 MHz to 200 MHz
7441. 15 to 160 MHz
7442. 200 to 3000 MHz
7443.
External noise fields are measured in terms of _______.
7444. rms values
7445. dc values
7446. average values
7447. peak values
7448.
Form of interference caused by rain or dust storms.
7449. Precipitation static
7450. Shot-noise
7451. Galactic noise
7452. Impulse noise
7453.
At 17˚ C, the noise voltage generated by 5kΩ resistor, operating over a bandwidth
of 20KHz is
7454. 1.3 nV
7455. 1.3 µV
7456. 1.3 pV
7457. 1.3 mV
7458.
________ is an electric noise produced by thermal agitation of electrons in
conductor and semiconductor.
7459. External noise
7460. Internal noise
7461. Thermal noise
7462. Flicker
7463.
Three identical circuits having 10 dB signal noise-to-noise ratio each are
connected in tandem with each other, what is the overall S/N?

7464. 5.23 dB
7465. 14.77dB
7466. 30 dB
7467. 40 dB
7468.
The noise figure of the first circuit in tandem connection is 10.5 dB while its
power gain is 15, what is the over all noise figure if the second circuit has a noise figure
of 11 dB?
7469. 11.59 dB
7470. 11.23 dB
7471. 10.79 dB
7472. 10.5 dB
7473.
Is the interference coming from other communications channels?
7474. Jitter
7475. Crosstalk
7476. RFI
7477. EMI
7478.
What is the reference noise level?
7479. 10 pW
7480. 0 dBm
7481. 1mW
7482. -90 dBm
7483.
What is the unit of noise power of psophometer?
7484. pWp
7485. dBa
7486. dBm
7487. dBrn
7488.
A large emission of hydrogen from the sun that affects communications.
7489. Solar flare
7490. Cosmic disturbance
7491. Ballistic disturbance
7492. Solar noise
7493.
Atmospheric noise is known as _______noise.
7494. static
7495. cosmic
7496. solar
7497. lunar
7498.
Standard design reference for environmental noise temperature.
7499. 300 K
7500. 290 K
7501. 32 ËšF
7502. 212ËšF
7503.
Absolute temperature in Kelvin.
7504. ËšC +273
7505. ËšC+75
7506. ËšC+19
7507. ËšC +290

7508.
If bandwidth is doubled, the signal power is _________.
7509. not changed
7510. quadrupled
7511. tripled
7512. doubled
7513.
Name one or more sources of noise bearing on electronic communications.
7514. Steam boiler
7515. Galaxies
7516. Internal combustion engine
7517. Both B and C
7518.
The transmitter technique adopted to reduce the noise effect of the preceding
question is called
7519. noise masking
7520. anitnoise
7521. noise killing
7522. preemphasis
7523.
Deemphasis in the receiver in effect attenuates modulating signal components and
noise in what frequency range?
7524. dc
7525. low
7526. intermediate
7527. high
7528.
Atmospheric noise or static is not a great problem
7529. at frequencies below 20 MHz
7530. at frequencies below 5 MHz
7531. at frequencies above 30 MHz
7532. at frequencies above 1 MHz
7533.
What is the proper procedure for suppressing electrical noise in a mobile station?
7534. Apply shielding and filtering where necessary
7535. Insulate a all plain sheet metal surfaces from each other
7536. Apply anti-static spray liberally to all nonmetallic
7537. Install filter capacitors in series with all dc wiring
7538.
Where is the noise generated that primarily determines the signal-to-noise ratio in
a VHF (150MHz) marine-band receiver?
7539. Man-made noise
7540. In the atmosphere
7541. In the receiver front end
7542. In the ionosphere
7543.
The difference between signal strength at a given point and a reference level
is________.
7544. power
7545. dBm
7546. level
7547. ratio
7548.
Interfering effect of noise, C message weighted, is _________.
7549. dBa

7550. dBm
7551. dBmc
7552. dB
7553.
F1A weighting refers to ___________.
7554. -90 dBm
7555. dBrnc0
7556. dBrnc
7557. F1A handset
7558.
Reading a 58 dBrnC on your Western Electric 3A test set at a +7 test point is
equal to ______ dBrnc0.
7559. 58
7560. 51
7561. 65
7562. 27
7563.
Reading a 58 dBrn, at a +7 test point is equal to ________ dBa0.
7564. 26
7565. 65
7566. 51
7567. 46
7568.
A reading of -50 dBm on the disturbing pair, and -80 on the disturbed pair equals
_____ dB of crosstalk coupling.
7569. 20
7570. 30
7571. 60
7572. 25
7573.
Power is __________.
7574. actual amount of power reference to 1mW
7575. logarithmic ratio of two powers
7576. definite amount of energy per time period
7577. current flow per time period
7578.
15 dBa F1A weighted, equals ___________.
7579. -90 dBm
7580. -82 dBm
7581. -85 dBm
7582. -70 dBm
7583.
You are measuring noise in a voice channel with a Lenkurt 601A, F1A weighting
network and a flat meter. Your meter reads -47dBm. What is this reading in dBa?
7584. 77 dBa
7585. 35 dBa
7586. 38 dBa
7587. 32 dBa
7588.
You are measuring noise at a +3 dB level point, using the Lenkurt 601A, F1A
weighting network, and a flat meter. The meter reading is -57dBm. This is
________dBa0.
7589. 20
7590. 15

7591. 25
7592. 17
7593.
You are measuring noise at a -6 dB level point, using the Lenkurt 601A, F1A
weighting network, and a flat meter. The meter reading is -59 dBm. This is _________
dBa0.
7594. 24
7595. 12
7596. 23
7597. 32
7598.
A measurement of -75 dBm, C-message weighted, would be _________ dBrnc.
7599. 8
7600. 7
7601. 9
7602. 15
7603.
Your Western Electric 3A test set meter reading is -23 dBm at at test point level of
-8 dB. This is ______ dBrnc0.
7604. 75
7605. 29
7606. 30
7607. 31
7608.
At what power level does a 1 KHz tone cause zero interference (144 weighted)?
7609. 90 dB
7610. 90 dBm
7611. -90 dBm
7612. -90 dBm
7613.
Reference noise is ___________.
7614. a 1000 Hz, -90 dBm tone
7615. a noise that creates the same interfering effect as a 1000Hz, -90dBm tone
7616. a noise that creates zero dBrn in a voice channel
7617. B and C above
7618.
A practical dBrn measurement will almost always in a _______ number.
7619. positive
7620. negative
7621. imaginary
7622. fractional
7623.
What is the reference level for noise measurement, F1A weighted?
7624. -90 dBm
7625. -82 dBm
7626. -67 dBm
7627. -85 dBm
7628.
What is the reference tone level for dBrn?
7629. -90 dBm
7630. -82 dBm
7631. -67 dBm
7632. -85 dBm
7633.
What is the reference tone level for dBa?

7634. -90 dBm
7635. -82 dBm
7636. -67 dBm
7637. -85 dBm
7638.
Atmospheric noise becomes less severe at frequencies
7639. above 30 MHz
7640. below 30 MHz
7641. above 3000 kHz
7642. below 3000kHz
7643.
Indicate the noise whose sources are in category different from that of the other
three?
7644. Solar noise
7645. Cosmic noise
7646. Atmospheric noise
7647. Galactic noise
7648.
Indicate the false statement.
7649. Industrial noise is usually of the impulse type
7650. Static is caused by lightning discharges in thunderstorms and other natural electric
disturbances occurring in the atmosphere
7651. Distant stars are another source of man-made noise
7652. Flourescent lights are another source of man-made noise
7653.
Which of the following is not a source of industrial noise?
7654. Automobile ignition
7655. Sun
7656. Electric Motors
7657. Leakage from high voltage line
7658.
Indicate the false statement
7659. The noise generated in a resistance or the resistive component of any impedance
is random.
7660. Random noise power is proportional to the bandwidth over which is measured
7661. A random voltage across the resistor does not exist
7662. All formula referring to random noise are applicable only to the value of such
noise.
7663.
The value of the resistor creating thermal noise is doubled. The noise power
generated is therefore.
7664. halved
7665. quadrupled
7666. doubled
7667. unchanged
7668.
Indicate the false statement.
7669. HF mixer are generally noisier than HF amplifiers.
7670. Impulse noise voltage is dependent on bandwidth
7671. Thermal noise is independent of the frequency at which is measured.
7672. Industrial noise is usually of the impulse type.
7673.
An amplifier operating over the frequency range of 455 to 460 kHz has a 200 kΩ
input resistor. What is the RMS noise voltage at the input to this amplifier if the ambient

temperature is 17ËšC ?
7674. 40 µV
7675. 4.0 µV
7676. 400 µV
7677. 4.0 mV
7678.
The first stage of a two-stage amplifier has a voltage gain of 10, a 600 Ω input
resistor, a 1600Ω equivalent noise resistance and 27kΩ output resistor. For the second
stage, these values are 25, 81kΩ, 19kΩ, and 1MΩ, respectively. Calculate the equivalent
input-noise resistance of this two stage amplifier.
7679. 2,518 kΩ
7680. 2,518 Ω
7681. 251.8 Ω
7682. 12,518 Ω
7683.
The noise output of a resistor is amplified by a noiseless amplifier having a gain
of 60 and a bandwidth of 20 kHz. A meter connected at the output of the amplifier reads
1mV RMS. If the bandwidth of the amplifier is reduced to 5kHz, its gain remaining
constant, what does the meter read now?
7684. 0.5 mV
7685. 0.5 µV
7686. 5.0 mV
7687. 5.0 µV
7688.
The front-end of a television receiver, having a bandwidth of 7Mhz, and
operating at a temperature of 27ËšC , consists of an amplifier having a gain of 15 followed
by a mixer whose gain is 20. The amplifier has a 300 Ω input resistor and a shot noise
equivalent resistance of 500Ω; for the mixer, these values are 2.2kΩ and 13.5kΩ
respectively, and the load resistance of the mixer is 470 kΩ. Calculate the equivalent
noise resistance for this television receiver.
7689. 8760 Ω
7690. 875Ω
7691. 8.76Ω
7692. 0.876Ω
7693.
One of the following is not a useful quantity for comparing the noise performance
receivers.
7694. Input noise voltage
7695. Equivalent noise resistance
7696. Noise temperature
7697. Noise figure.
7698.
Indicate the false statement. Noise figure is defined as
7699. the ratio of the S/N power supplied at the input terminal of a receiver or amplifier
to the S/N power supplied to the output or load resistor
7700. noise factor expressed in decibels
7701. an unwanted form of energy tending to interfere with the proper and easy
reception and reproduction of wanted signals
7702. S/N of an ideal system divided by S/N at the output of the receiver or amplifier
under test, both working at the same temperature over the same bandwidth and fed
from the same source

7703.
Calculated the noise figure of the amplifier whose Req equals 2518Ω (RT=600Ω)
if its driven by a generator whose output impedance is 50Ω.
7704. 39.4
7705. 3.94
7706. 394
7707. 0.394
7708.
Calculate the noise figure of the receiver whose RF amplifier has an input
resistance of 1000Ω and an equivalent shot-noise resistance of 2000Ω, a gain of 25 and
load resistance of 125 kΩ. Given that the bandwidth is 1.0MHz and the temperature is
20˚C, and that the receiver is connected to an antenna with an impedance of 75Ω.
7709. 30.3
7710. 3.03
7711. 303
7712. .303
7713.
A receiver connected to an antenna whose resistance is 50 Ω has an equivalent
noise resistance of 30Ω. Calculate its equivalent noise temperature if the noise figure is
equal to 1.6.
7714. 17.4 K
7715. 174K
7716. 1.74K
7717. 17K
7718.
Most internal noise comes from
7719. Shot noise
7720. Transit-time noise
7721. Thermal agitation
7722. Skin effect
7723.
Which of the following is not a source of external noise?
7724. Thermal agitation
7725. Auto ignition
7726. The sun
7727. Fluorescent lights
7728.
Noise can be reduced by
7729. widening the bandwidth
7730. narrowing the bandwidth
7731. increasing temperature
7732. increasing transistor current levels
7733.
Noise at the input to the receiver can be as high as several
7734. microvolts
7735. milivolts
7736. volts
7737. kilo volts
7738.
Which circuit contributes most of the noise in a receiver?
7739. IF amplifier
7740. Demodulator
7741. AF amplifier
7742. Mixer

7743.
Which noise figure represents the lowest noise in receiver?
7744. 1.6 dB
7745. 2.1 dB
7746. 2.7 dB
7747. 3.4 dB
7748.
The transistor with the lowest noise figure in the microwave region is a
7749. MOSFET
7750. Dual-gate MOSFET
7751. JFET
7752. MESFET
7753.
What is the noise voltage across a 300Ω input resistance to a TV set with a 6MHz
bandwidth and temperature of 30ËšC?
7754. 2.3 µV
7755. 3.8µV
7756. 5.5µV
7757. 5.4µV
7758.
Which of the following types of noise becomes of great importance at
frequencies?
7759. Shot noise
7760. Random noise
7761. Impulse noise
7762. Transit-time noise
7763.
The solar cycle repeats the period of great electrical disturbance approximately
every
7764. 11 years
7765. 10 years
7766. 9 years
7767. 8 years
7768.
The square of the thermal noise voltage generated by a resistor is proportional to
7769. its resistance
7770. its temperature
7771. the bandwidth over which it is measured
7772. All of the above
7773.
Noise occurring in the presence of signal resulting from a mismatch between the
exact value of an analog signal and the closet available quantizing step in a digital coder.
7774. Quantizing noise
7775. Thermal noise
7776. Impulse noise
7777. Crosstalk
7778.
Noise consisting of irregular pulses of short duration and relatively high
amplitude,
7779. Quantizing noise
7780. Tone interference
7781. Impulse noise
7782. Cross talk
7783.
Noise that occurs via capacitive or inductive coupling in a cable.

7784. Crosstalk
7785. Quantizing noise
7786. Reference noise
7787. Tone interference
7788.
Sources of impulse noise induced in communication channels.
7789. Erroneous digital coding bit caused by an error on a transmission facility
7790. Transients due to relay operation
7791. Crosstalk from dc signaling systems
7792. All of these
7793.
Crosstalk due to incomplete suppression of sidebands or to intermodulation of
two or more frequency-multiplexed channels which is unintelligible is classified as
7794. Impulse noise
7795. Thermal noise
7796. Quantizing noise
7797. Miscellaneous noise
7798.
___________ is device that measures the internal open circuit voltage of an
equivalent noise generator having an impedance of 600Ω and delivering noise power to a
600 Ω load.
7799. Psophometer
7800. Barometer
7801. Reflectometer
7802. Voltmeter
7803.
External noise originating outside the solar system
7804. Cosmic noise
7805. Solar noise
7806. Thermal noise
7807. Lunar noise
7808.
A noise whose source is within the solar system.
7809. Solar noise
7810. Thermal noise
7811. Cosmic noise
7812. Johnson Noise
7813.
The total noise power present in a 1-Hz bandwidth .
7814. Noise density
7815. Noise figure
7816. Noise limit
7817. Noise intensity
7818.
Which of the following is not a way of minimizing if not eliminating noise?
7819. Use redundancy
7820. Increase transmitted power
7821. Reduce signaling rate
7822. Increase channel bandwidth
7823.
What is the primary cause of atmospheric noise?
7824. Thunderstorm
7825. Lightning
7826. Thunderstorm and lightning

7827. Weather condition
7828.
What do you call the noise coming from the sun and stars?
7829. Black-body noise
7830. Space noise
7831. Galactic noise
7832. All of these
7833.
The major cause of atmospheric or static noise are
7834. Thunderstorms
7835. Airplanes
7836. Meteor showers
7837. All of these
7838.
Which of the following low noise transistors is commonly used at microwave
frequencies?
7839. MOSFET
7840. GASFET
7841. MESFET
7842. JFET
7843.
7844.
7845.
7846.
Satellite Communications Chapter 10(3001 Questions in Communications
Engineering-EXCEL REVIEW CENTER
7847.
Which of the following is the first active satellite?
7848. Echo I
7849. Telstar I
7850. Early Bird
7851. Sputnik I
7852.
Which of the following is the first commercial satellite?
7853. Early Bird
7854. Telstar
7855. Explorer
7856. Courier
7857.
What is the first passive satellite transponder?
7858. Sun
7859. Early Bird
7860. Score
7861. Moon
7862.
The first satellite to receive and transmit simultaneously
7863. Intelsat I
7864. Agila I
7865. Syncorn I
7866. Telstar I
7867.
A helical antenna is used for satellite tracking because of
7868. circular polarization
7869. maneuverability
7870. beamwidth

7871. gain
7872.
Repeaters inside communications satellites are known as
7873. Trancievers
7874. Transponders
7875. Transducers
7876. TWT
7877.
Considered as the unsolved problem in satellite system
7878. Coverage
7879. Cost
7880. Access
7881. Privacy
7882.
___________ is a satellite that rotates around the earth in a low-altitude elliptical
or circular pattern.
7883. Geosynchronous satellite
7884. Nonsynchronous satellite
7885. Prograde satellite
7886. Retrograde satellite
7887.
Is the geographical representation of a satellite antenna radiation pattern
7888. Footprint
7889. Spot
7890. Earth
7891. Region
7892.
The smallest beam of a satellite antenna radiation pattern
7893. Zone beam
7894. Hemispheric beam
7895. Spot beam
7896. Global beam
7897.
A satellite beam that covers almost 42.4% of the earths surface.
7898. Zone beam
7899. Hemispheric beam
7900. Spot beam
7901. Global beam
7902.
What is the frequency range of C-band?
7903. 8.5 to 12.5 GHz
7904. 3.4 to 6.425 GHz
7905. 12.95 to 14.95 GHz
7906. 27.5 to 31 GHz
7907.
A satellite signal transmitted from a satellite transponder to earth’s station.
7908. Uplink
7909. Downlink
7910. Terrestrial
7911. Earthbound
7912.
Collects very weak signals from a broadcast satellite
7913. Helical antenna
7914. Satellite dish
7915. LNA

7916. TWT
7917.
What is a device that detects both vertically and horizontally polarized signals
simultaneously?
7918. Orthomode transducer
7919. Crystal detector
7920. Optoisolator
7921. Isomode detector
7922.
_________ detects the satellite signal relayed from the feed and converts it to an
electric current, amplifies and lower its frequency.
7923. Horn antenna
7924. LNA
7925. Satellite receiver
7926. Satellite dish
7927.
Is a loss of power of a satellite downlink signal due to earth’s atmosphere.
7928. Atmospheric loss
7929. Path loss
7930. Radiation loss
7931. RFI
7932.
What height must a satellite be placed above the surface of the earth in order for
its rotation to be equal to earth’s rotation?
7933. 26,426.4 miles
7934. 27,426.4 miles
7935. 23,426.4 miles
7936. 22,426.4 miles
7937.
Point on the satellite obits closest to the earth.
7938. Apogee
7939. Perigee
7940. Prograde
7941. Zenith
7942.
The earth area covered by a satellite radio beam.
7943. Beamwidth
7944. Bandwidth
7945. Footprint
7946. Zone
7947.
What is the local oscillator (mixer) frequency of the satellite with an uplink
frequency in GHz band?
7948. 3500 MHz
7949. 4500 MHz
7950. 2225 MHz
7951. 2555 MHz
7952.
What kind of battery panels are used in some advance satellites
7953. Germanium based panels
7954. Silicon based panel
7955. Galium Phosphate solar panel array
7956. Galium Arsenide solar panel array
7957.
Satellite engine uses

7958.
7959.
7960.
7961.
7962.
7963.
7964.
7965.
7966.
7967.
7968.
7969.
7970.
7971.
7972.
7973.
7974.
7975.
7976.
7977.
7978.
7979.
7980.
7981.
7982.
7983.
7984.
7985.
7986.
7987.
7988.
7989.
7990.
7991.
7992.
ITU?
7993.
7994.
7995.
7996.
7997.
7998.
7999.
8000.
8001.
8002.

jet propulsion
ion propulsion system
liquid fuel
solar jet
A satellite batter has more power but lighter.
Lithium
Leclanche
Hydrogen
Magnesium
What kind of battery used by older satellites?
Lithium
Leclanche
Hydrogen
Magnesium
VSAT was made available in
1979
1981
1983
1977
What band does VSAT first operate?
L-band
X-band
C-band
Ku-band
The first Philippine Mabuhay satellite has how many channels?
30
24
48
50
The first Philippine Agila I will have how many transpoders.
36
48
24
12
How may satellite orbital slots are requested by the Philippine Government from
2
4
6
8
The location of AsiaSat I.
105.5ËšEast
151.5ËšEast
115.5ËšEast
170.5ËšEast
AsiaSat I covers how many countries in Asia?

8003. 38
8004. 10
8005. 28
8006. 15
8007.
The owner of AsiaSat 2 is
8008. Asia Satellite Telecommunications Company (ASTC)
8009. Japan Satellite System (JSAT)
8010. China Great Wall Industry Corporation
8011. Singapore Satellite Commision
8012.
What is the approximate path loss from satellite-to-earth station?
8013. 100 dB
8014. 150 dB
8015. 175 dB
8016. 200 dB
8017.
INTELSAT stands for
8018. Intel Satellite
8019. International Telephone Satellite
8020. International Telecommunications Satellite
8021. International Satellite
8022.
The frequency of Ku band for satellite communications.
8023. 6/4 GHz
8024. 14/11 GHz
8025. 12/14 GHz
8026. 4/8 GHz
8027.
A satellite cross-link means
8028. Earth-to-satellite link
8029. Satellite-to-earth link
8030. Satellite-to-satellite link
8031. None of these
8032.
Earth station uses what type of antenna
8033. Despun antenna
8034. Helical antenna
8035. Toroidal antenna
8036. Cassegrain antenna
8037.
What is the delay time for satellite transmission from earth transmitter to earth
receiver?
8038. 0.5 s
8039. 1.0 s
8040. 5 ms
8041. 0.25 ms
8042.
The bandwidth of C-band satellite frequency band in U.S.
8043. 500 GHz
8044. 1000 GHz
8045. 1000 MHz
8046. 500 MHz
8047.
The most common device used as an LNA is

8048. zener diode
8049. tunnel diode
8050. IMPATT
8051. Shockley diode
8052.
The radiation patterns of earth coverage antennas have a beamwidth of
approxiamately
8053. 21Ëš
8054. 5Ëš
8055. 17Ëš
8056. 35Ëš
8057.
A mobile satellite array has usually how many elements?
8058. 6
8059. 88
8060. 12
8061. 14
8062.
In a typical mobile satellite array antenna if three elements are activated, how
many elements are deactivated?
8063. 3
8064. 11
8065. 5
8066. 9
8067.
What circuit is responsible in activating and deactivating adjacent antenna
elements in a mobile satellite array?
8068. Radial divider
8069. Divider/combiner
8070. Radial combiner
8071. Radial multiplexer
8072.
Most mobile satellite array uses ___________ in transforming 50 to 150 Ω
impedance.
8073. stub
8074. balun
8075. quarter-wavelength transformer
8076. microstrip tapers.
8077.
The switching from one element to the other element in a typical mobile satellite
array.
8078. Series
8079. Radial
8080. Matrix
8081. Shunt
8082.
A method of multiple accessing where a given RF channel bandwidth is divided
inot smaller frequency band.
8083. CDMA
8084. ANIK-D
8085. TDMA
8086. FDMA
8087.
What is the delay time for satellite transmissions from earth transmitter to earth

receiver?
8088. 0.5 s
8089. 1s
8090. 5 ms
8091. 0.25 s
8092.
As the height of a satellite orbit gets lower, the speed of the satellite _________.
8093. increases
8094. decreases
8095. remains the same
8096. None of the above
8097.
The main function of a communications satellite is a/ an
8098. repeater
8099. reflector
8100. beacon
8101. observation platform
8102.
The key electronic component in a communications satellite is the
8103. telemetry equipment
8104. on-board computer
8105. command and control system
8106. transponder
8107.
A circular orbit around the equator with a 24-h period is called a/an
8108. elliptical orbit
8109. geostationary orbit
8110. polar orbit
8111. transfer orbit
8112.
A satellite stay in orbit because the following two factors are balanced
8113. Satellite weight and speed
8114. Gravitational force and centrifugal force
8115. Centripetal force and speed
8116. Satellite weight and the pull of the moon and sun
8117.
What is the height of a satellite in a synchronous equatorial orbit?
8118. 42000 mi
8119. 6800 mi
8120. 22,300 mi
8121. 35,860 mi
8122.
Most satellites operate in which frequency band?
8123. 30 to 300 MHz
8124. 300 MHz to 3 GHz
8125. 3 GHz to 30 GHz
8126. Above 300 GHz
8127.
The main power sources for a satellite are
8128. batteries
8129. solar cells
8130. fuel cells
8131. thermoelectric generators
8132.
The maximum height of an elliptical orbit is called the

8133.
8134.
8135.
8136.
8137.
8138.
8139.
8140.
8141.
8142.
8143.
8144.
8145.
8146.
8147.
8148.
8149.
8150.
8151.
8152.
8153.
8154.
8155.
8156.
8157.
8158.
8159.
8160.
8161.
8162.
8163.
8164.
8165.
8166.
8167.
8168.
8169.
8170.
8171.
8172.
8173.
8174.
8175.
8176.
8177.
8178.

Perigee
Apex
Zenith
Apogee
Batteries are used to power all satellite subsystems
at all times
only during emergencies
during eclipse periods
to give the solar arrays a rest
The satellite subsystem that monitors and controls the satellite is the
propulsion subsystem
power subsystem
communications subsystem
telemetry, tracking, and command subsystem
What is the basic technique used to stabilize a satellite?
Gravity-forward motion balance
Spin
Thruster control
Solar panel orientation
The jet thrusters are usually fired to
maintain altitude
put the satellite into the transfer orbit
inject the satellite in the geosynchronous orbit
bring the satellite back to earth.
Most commercial satellite activity occurs in which band(s)?
L
C and Ku
X
S and P
How can multiple earth stations share a satellite on the same frequencies?
Frequency reuse
Multiplexing
Mixing
Frequency hopping
What is the typical bandwidth of a satellite band?
36 MHz
40 MHz
70 MHz
500 MHz
Which of the following is not usually a part of a transponder are defined by the
LNA
Mixer
Modulator
HPA
The satellite communications channels in a transponder are defined by the
LNA

8179. bandpass filter
8180. mixer
8181. input signals
8182.
The HPAs in most satellite are
8183. TWTs
8184. Klystrons
8185. Vacuum tubes
8186. Magnetrons
8187.
The physical location of a satellite is determined by its
8188. distance from the earth
8189. latitude and longitude
8190. reference to the stars
8191. position relative to the sun
8192.
The receive GCE system in an earth station performs what function(s)?
8193. Modulation and multiplexing
8194. Up conversion
8195. Demodulation and demultiplexing
8196. Down conversion
8197.
Which of the following types of HPA is not used in earth stations?
8198. TWT
8199. Transistor
8200. Klystron
8201. Magnetron
8202.
What is the common up-converter and down-converter IF?
8203. 36 MHz
8204. 40 MHz
8205. 70 MHz
8206. 500 MHz
8207.
What type of modulation is used on voice and video signals?
8208. AM
8209. FM
8210. SSB
8211. QPSK
8212.
What modulation is normally used with digital data?
8213. AM
8214. FM
8215. SSB
8216. QPSK
8217.
Which of the following is not a typical output from a GPS receiver?
8218. Latitude
8219. Speed
8220. Altitude
8221. Longitude
8222.
The total space loss of transmission and reception for two ground stations with
uplink frequency 8GHz and a downlink of 6 GHz with angle of elevations of 3Ëš and 7Ëš A
respectively is

8223. 403 dB
8224. 100 dB
8225. 20 dB
8226. 215 dB
8227.
The maximum propagation delay of a geostationary satellite is
8228. 278 ms
8229. 239 ms
8230. 300 ms
8231. 250 ms
8232.
The total propagation delay time from transmission to reception of signals from a
ground transmitter to ground receiver with angle of elevation at 10 degrees respectively is
8233. 273 ms
8234. 239 ms
8235. 275 ms
8236. 260 ms
8237.
A satellite which simply reflects the signal without further amplification
8238. Passive satellite
8239. Active satellite
8240. Geostationary satellite
8241. Domestic satellite
8242.
Essentially a satellite ___________ is a radio repeater in the sky
8243. transponder
8244. comparator
8245. duplexer
8246. billboard
8247.
Satellite the orbits in a circular pattern with an angular velocity equal to that of
the earth
8248. Geostationary
8249. Early Bird I
8250. Syncorn I
8251. Stationary satellite
8252.
Satellite that provide services within a single country
8253. Domsat
8254. Comsat
8255. Regional
8256. Global
8257.
The round-trip propagation delay between two earth stations through a
geosynchronous satellite is
8258. 500 to 600 ms
8259. 300 to 400 ms
8260. 600 to 700 ms
8261. 400 to 500 ms
8262.
The signal path from earth station satellite
8263. Uplink signal
8264. Reflected signal
8265. Incident signal

8266. Downlink signal
8267.
Designed to receive a signal from a transmitting station on the ground and
retransmit it to a receiving station located elsewhere
8268. Communication satellite
8269. Repeater
8270. Relay station
8271. Transponder
8272.
The signal path from satellite to earth-based receiver.
8273. Downlink signal
8274. Uplink signal
8275. Incident signal
8276. Reflected signal
8277.
A satellite position is measured by its __________ angle with respect to the
horizon.
8278. elevation
8279. depression
8280. azimuth
8281. critical
8282.
The ________ angle measures the satellite position clockwise from the direction
of true north.
8283. azimuth
8284. elevation
8285. depression
8286. critical
8287.
incidentally propose the geostationary scheme or orbit of the satellite in 1940s
8288. Arthur Clarke
8289. Carl Friedrich Gauss
8290. Samuel Morse
8291. Stephen Gray
8292.
When the satellite are spaced 4Ëš of the 360Ëš complete circle, how many parking
spaces or orbit slots are available?
8293. 90
8294. 85
8295. 95
8296. 80
8297.
The control routine necessary to keep the satellite in position is referred to as
8298. station keeping
8299. station tracking
8300. station monitoring
8301. station maintaining
8302.
Refers to the satellite orientation with respect to the earth
8303. Satellite altitude
8304. Satellite position
8305. Satellite location
8306. Satellite orbit
8307.
The first intelsat satellite that was launched in 1965 was named

8308. Early Bird I
8309. Echo
8310. Telstar I
8311. Courier
8312.
The first satellite launched for a geosynchronous orbit but unfortunately lost
during orbit injection
8313. Syncom I
8314. Telstar I
8315. Sputnik I
8316. Early Bird I
8317.
When the elevation angle of a geostationary satellite is 23Ëš and the transmitting
frequency is 3840 MHz, what is the free space loss in dB?
8318. 196 dB
8319. 200 dB
8320. 150 dB
8321. 100 dB
8322.
What is the propagation delay when a signal is transmitter by an earth station to a
geosynchronous satellite about 38,500 km above earth’s equator and then received by the
same earth station?
8323. 256 msec
8324. 128 msec
8325. 300 msec
8326. 400 msec
8327.
What is the free space attenuation of a satellite communications system operating
at 36,000 km above the earth at 5.0 GHz?
8328. 198 dB
8329. 202 dB
8330. 142 dB
8331. 138 dB
8332.
Which of the following is the most common application of satellite?
8333. Surveillance
8334. Military application
8335. Communications
8336. Newscasting
8337.
Descending pass for a satellite means a pass from
8338. North to South
8339. South to North
8340. East to West
8341. West to East
8342.
Geostationary stationary satellites are located ___________ with respect to the
equator.
8343. 0Ëšlongitude
8344. 0Ëš latitude
8345. 90Ëšlatitude
8346. 45 latitudeËš
8347.

8348.
8349.
8350.
8351.
8352.
8353.
8354.
8355.
8356.
8357.
8358.
8359.
8360.
8361.
8362.
8363.
8364.
8365.
8366.
8367.
8368.
8369.
8370.
8371.
8372.
8373.
8374.
8375.
8376.
8377.
8378.
8379.
8380.
8381.
8382.
8383.
8384.
3001 Questions in Communications Engineering – EXCEL REVIEW
CENTER
8385.
Chapter 6 - Antennas
8386.
8387.
1. What is the polarization of a discone antenna?
8388.
A. Vertical
8389.
B. Horizontal
8390.
C. Circular
8391.
D. Spiral
8392.

8393.
2. If the antenna increases 3.3 times how much does the radiated power increase?
8394.
A. 3.3 times
8395.
B. 10.89 times
8396.
C. 9.9 times
8397.
D. 6.6 times
8398.
8399.
3. When speaking of antennas. ______ is a section which would be a complete
antenna by itself.
8400.
A. image
8401.
B. top loading
8402.
C. bay
8403.
D. quarterwave
8404.
8405.
4. In what range of frequencies are most omnidirectional horizontally polarized
antennas used?
8406.
A. VHF, UHF
8407.
B. VLF, LF
8408.
C. SH, EHF
8409.
D. MF, HF
8410.
8411.
5. If the current ratios of the two or more elements must be held 5% and the phase
angle to 3° the antenna is called a
8412.
A. end fire array
8413.
B. critical phased array
8414.
C. broadband array
8415.
D. wideband array
8416.
8417.
6. A device that converts high frequency current into electromagnetic wave.
8418.
A. Antenna
8419.
B. Loudspeaker
8420.
C. Microphone
8421.
D. Transducer
8422.
8423.
7. Which is a non-resonant antenna?
8424.
A. Rhombic antenna
8425.
B. Folded dipole
8426.
C. End-fire array
8427.
D. Yagi-Uda antenna
8428.
8429.
8. Gain of a half-wave dipole antenna over isotropic.
8430.
A. 2.15 dB
8431.
B. 1.76 dB
8432.
C. 1 dB
8433.
D. 0dB
8434.
8435.
9. Very low signal strength in antenna.

8436.
A. Minor lobes
8437.
B. Null
8438.
C. Antenna patterns
8439.
D. Major lobes
8440.
8441.
10. What is the gain of the Hertzian dipole over isotropic antenna?
8442.
A. 1.64 dB
8443.
B. 2.15 dB
8444.
C. 1.76 dB
8445.
D. 1.55 dB
8446.
8447.
11. ______ is the measurement of a unilateral antenna properties of directivity
8448.
A. Phase angle
8449.
B. Antenna gain
8450.
C. Beamwidth
8451.
D. Bandwidth
8452.
8453.
12. In testing transmitter to prevent interfering with other stations, which type of
antenna must be used?
8454.
A. Void antenna
8455.
B. Dummy antenna
8456.
C. Hertzian antenna
8457.
D. Isotropic antenna
8458.
8459.
13. The best solution to fading is _____.
8460.
A. space diversity
8461.
B. frequency diversity
8462.
C. polarization diversity
8463.
D. wavelength diversity
8464.
8465.
14. _____ is the amount of uncertainty in a system of symbols
8466.
A. Bandwidth
8467.
B. Enthalpy
8468.
C. Entropy
8469.
D. Quantum
8470.
8471.
8472.
8473.
8474.
15. If an antenna has a gain of 3 dB, it increases the output of the transmitter by
8475.
A. 10,000 times
8476.
B. 1000 times
8477.
C. 100 times
8478.
D. 1 million times
8479.
8480.
16. Top loading is used in an antenna in order to increase its ______.

8481.
A. practical height
8482.
B. beamwidth
8483.
C. effective height
8484.
D. input capacitance
8485.
8486.
17. A horizontal antenna is _____.
8487.
A. vertically polarized
8488.
B. horizontally polarized
8489.
C. centrally polarized
8490.
D. circularly polarized
8491.
8492.
18. All elements in a beam _____ antennas are in line
8493.
A. collinear
8494.
B. yagi
8495.
C. broadside array
8496.
D. log-periodic
8497.
8498.
19. Which does not use vertical polarization antenna?
8499.
A. AM Broadcasting
8500.
B. FM Broadcasting
8501.
C. Mobile Communications
8502.
D. Satellite Communications
8503.
8504.
20. Lightning rods must be mounted a top structure not less than ___ above the
highest point.
8505.
A. 10 cm
8506.
B. 20 cm
8507.
C. 30 cm
8508.
D. 40 cm
8509.
8510.
21. _____ is an antenna with a number of half-wave antenna on it.
8511.
A. Antenna array
8512.
B. Tower
8513.
C. Omni-directional
8514.
D. Rhombic
8515.
8516.
8517.
8518.
8519.
22. Which antenna radiates an omnidirectional pattern in the horizontal plane with
vertical polarization?
8520.
A. Marconi antenna
8521.
B. Discone antenna
8522.
C. Horn antenna
8523.
D. Helical antenna
8524.

8525.
23. An antenna with very high gain and very narrow beamwidth.
8526.
A. Helical antenna
8527.
B. Discone antenna
8528.
C. Horn antenna
8529.
D. Parabolic dish antenna
8530.
8531.
24. What determines antenna polarization?
8532.
A. The frequency of the radiated wave
8533.
B. The direction of the radiated wave
8534.
C. The direction of the magnetic field vector
8535.
D. The direction of the electric field vector
8536.
8537.
25. _____ is the horizontal pointing angle of an antenna
8538.
A. Azimuth
8539.
B. Angle of elevation
8540.
C. Right angle
8541.
D. Beamwidth
8542.
8543.
26. A dipole antenna requires to be fed with 20 kW of power to produce a given
signal strength to a particular distant point. If the addition of a reflector makes the same
field strength available with an input power of 11kW. What is the gain in dB, obtained by
the use if the reflector. (Gain referred to this particular dipole).
8544.
A. 4.75
8545.
B. 2.6
8546.
C. 1.81
8547.
D. 4.24
8548.
8549.
27. What is the estimated medium wind loading in the Philippines for antenna
tower design?
8550.
A. 300 kph
8551.
B. 100 kph
8552.
C. 200 kph
8553.
D. 250 kph
8554.
8555.
28. Discone radiation pattern is ______.
8556.
A. omnidirectional/vertical polarized
8557.
B. unidirectional
8558.
C. bidirectional
8559.
D. figure of eight
8560.
8561.
29. _____ is an open-ended slot antenna
8562.
A. Helical antenna
8563.
B. Rhombic antenna
8564.
C. Notch antenna
8565.
D. Cassegrain antenna
8566.

8567.
8568.
8569.
8570.
8571.
8572.
8573.
8574.
8575.
8576.
8577.
8578.
8579.
8580.
8581.
8582.
8583.
8584.
8585.
8586.
8587.
8588.
8589.
8590.
8591.
8592.
8593.
8594.
8595.
8596.
8597.
8598.
8599.
8600.
8601.
8602.
8603.
8604.
8605.
8606.
8607.
8608.
8609.
8610.
8611.
8612.

30. Which antenna is a properly terminated?
A. Marconi
B. Rhombic
C. Dipole
D. Yagi-Uda
31. What is the radiation characteristic of a dipole antenna?
A. Omnidirectional
B. Bidirectional
C. Unidirectional
D. Hemispherical
32. What is the theoretical gain of a Hertzian dipole?
A. 1.76 dB
B. 2.15 dB
C. 3 dB
D. 0 dB
33. An antenna with unity gain
A. Rhombic
B. Half-wave dipole
C. Isotropic
D. Whip
34. How will you increase the gain of an antenna?
A. By adding several antennas in parallel
B. By focusing the radiated energy in one desired direction
C. By making antenna rods thicker
D. By making the antenna size larger
35. An antenna which is one-tenth wavelength long
A. Hertzian dipole
B. Loop antenna
C. Marconi antenna
D. Elementary doublet

36. What is the minimum number of turns a helix antenna must have?
A. 3
B. 5
C. 4
D. 6

8613.
37. What is the gain of isotropic antenna?
8614.
A. 10
8615.
B. 1
8616.
C. 10
8617.
D. 100
8618.
8619.
38. Which of the following improves antenna directivity?
8620.
A. Driven element
8621.
B. Reflector element
8622.
C. Director element
8623.
D. Parasitic element
8624.
8625.
39. The antenna radiates _____ polarized waves when the transmitter antenna is
horizontally installed.
8626.
A. Vertically
8627.
B. negatively
8628.
C. horizontally
8629.
D. circularly
8630.
8631.
40. The length of a Marconi antenna to operate with 985 kHz is ______.
8632.
A. 200 ft
8633.
B. 500 ft
8634.
C. 250 ft
8635.
D. 999 ft
8636.
8637.
41. What is the front-to-back ratio of an antenna which radiates 500 watts in a
northernly direction and 50 watts in a southernly direction?
8638.
A. 25000 dB
8639.
B. 10 dB
8640.
C. 100 dB
8641.
D. 20 dB
8642.
8643.
42. If 4 kW in antenna produces 50 μV/m in a receiving antenna, a 15 kW will
produce _____.
8644.
A. 200 μV/m
8645.
B. 10 μV/m
8646.
C. 100 μV/m
8647.
D. 20 μV/m
8648.
8649.
8650.
8651.
43. If the radiated power increase 10.89 times, the antenna current increases by
______.
8652.
A. 3.3 times
8653.
B. 6.6 times
8654.
C. 1.82 times

8655.
D. 10.89 times
8656.
8657.
44. The frequency of operation of a dipole antenna cut to a length of 3.4 m.
8658.
A. 88 MHz
8659.
B. 44 MHz
8660.
C. 22 MHz
8661.
D. 11 MHz
8662.
8663.
45. Comparing the signal strength arriving at the driven element from the desired
direction to the signal strength reaching the driver from the opposite direction.
8664.
A. Directivity
8665.
B. Sensitivity
8666.
C. Beamwidth
8667.
D. Front-to-back ratio
8668.
8669.
46. What is the capture area of a dipole operated at 75 MHz?
8670.
A. 4 mm
8671.
B. 2 m2
8672.
C. 2.088 m2
8673.
D. 4.088 m2
8674.
8675.
47. _____ of an antenna is a measure of how the antenna concentrates its radiated
power in a given direction.
8676.
A. Efficiency
8677.
B. Power
8678.
C. Gain
8679.
D. Polarization
8680.
8681.
48. Shortening effect of an antenna that makes it appear as if it were 5% longer.
8682.
A. End effect
8683.
B. Flywheel effect
8684.
C. Skin effect
8685.
D. Capture effect
8686.
8687.
49. Harmonic suppressor connected to an antenna.
8688.
A. Low-pass filter
8689.
B. High-pass filter
8690.
C. M-derived filter
8691.
D. Constant-K
8692.
8693.
8694.
8695.
50. A simple half-wavelength antenna radiates the strongest signal
8696.
A. at 45 degrees to its axis
8697.
B. parallel to its axis
8698.
C. at right angles to its axis

8699.
D. at 60 degrees to its axis
8700.
8701.
51. The current maximum in a Marconi antenna is found at
8702.
A. the base of the antenna
8703.
B. the center of the antenna
8704.
C. some point between the base and the center of the antenna
8705.
D. the top of the antenna
8706.
8707.
52. If an antenna is too short for the wavelength being used, the effective length
can be increased by adding:
8708.
A. capacitance in series
8709.
B. inductance in series
8710.
C. resistance in parallel
8711.
D. resistance in series
8712.
8713.
53. Which of the following antennas is used for testing and adjusting a transmitter
for proper modulation, amplifier operation and frequency accuracy?
8714.
A. Elementary
8715.
B. Real
8716.
C. Isotropic
8717.
D. Dummy
8718.
8719.
54. The power fed to a two-bay turnstile antenna is 100 watts. If the antenna has a
2 dB power gain, what is the effective radiated power?
8720.
A. 317 watts
8721.
B. 158 watts
8722.
C. 200 watts
8723.
D. 400 watts
8724.
8725.
55. What is the gain, in dB of a helical antenna with diameter of λ/3, 10 turns at
pitch of λ/4, used at 100 MHz?
8726.
A. 16
8727.
B. 41.1
8728.
C. 31.4
8729.
D. 1.25
8730.
8731.
56. How is it possible to lower the resonant frequency of Hertz dipole antenna?
8732.
A. By reducing the frequency at the transmitter
8733.
B. By connecting a capacitor in series with the antenna
8734.
C. By the connecting a resistor in series with the antenna
8735.
D. By connecting an inductor in series with the antenna
8736.
8737.
57. Which of the following antennas receive signals in the horizontal plane
equality well from all directions?
8738.
A. Horizontal Hertz antenna
8739.
B. Vertical loop antenna

8740.
C. Vertical Yagi antenna
8741.
D. A vertical antenna which is a quarter-wavelength long
8742.
8743.
58. If the length of a Hertz dipole is decreased
8744.
A. its resonant frequency will be lowered its distributed inductance will be
increased
8745.
B. its distributed inductance will be decreased
8746.
C. its resonant frequency will be increased
8747.
D. its distributed capacitance between the antenna and ground will be
increased.
8748.
8749.
59. A final amplifier of a radio transmitter draws 250 mA of plate current when
the plate supply voltage is 1400 volts. If the plate circuit efficiency is 80% and the
transmitter is connected to an antenna having a feed impedance of 70 ohms, what is the
antenna current at the feed-point?
8750.
A. 4.0 A
8751.
B. 2.2 A
8752.
C. 1.25 A
8753.
D. 2.0 A
8754.
8755.
60. A one-quarter wavelength shunt-fed vertical Marconi antenna
8756.
A. has maximum radiation in a vertical direction
8757.
B. must have a horizontal receiving antenna for the best reception
8758.
C. must use a receiving antenna for the best reception
8759.
D. must have a vertical receiving antenna for the best reception
8760.
8761.
61. A shunt-fed quarter-wavelength Marconi antenna
8762.
A. has maximum RF impedance to ground at its feedpoint
8763.
B. has a current null at its feedpoint
8764.
C. has a zero DC resistance to ground
8765.
D. has zero RF resistance to ground
8766.
8767.
62. The parasitic element of an antenna system will
8768.
A. decrease its directivity
8769.
B. increase its directivity
8770.
C. give the antenna unidirectional properties
8771.
D. both B and C
8772.
8773.
63. If the length of an antenna is changed from 2.5 meters to 2.8 meters, its
resonant frequency will
8774.
A. increase
8775.
B. depend on the velocity factor so the resonant frequency can either be
increased or decreased
8776.
C. will be unchanged
8777.
D. decrease
8778.
64. What is the effect of adding a capacitor in series with an antenna?

8779.
A. The antenna’s resonant frequency will increase
8780.
B. The antenna’s resonant frequency will decrease
8781.
C. The antenna will be physically 5% longer than its electrical length
8782.
D. A capacitor is never added in series with an antenna
8783.
8784.
65. How does the electric field strength of a standard broadcast station vary with
the distance from the antenna?
8785.
A. The field strength of a standard broadcast station vary with the distance
from the antenna
8786.
B. The field strength is directly proportional to the distance from the
antenna
8787.
C. The field strength remains constant regardless of the distance from the
antenna
8788.
D. The field strength varies inversely as the distance from the antenna
8789.
8790.
66. Stacking elements in a transmitting antenna system
8791.
A. increases the field strength at the receiving antenna
8792.
B. increases the directivity of the transmitter antenna
8793.
C. decrease the size of the lobe in the radiation pattern
8794.
D. both A and B
8795.
8796.
67. A vertical loop antenna has a
8797.
A. unidirectional radiation pattern in the horizontal plane
8798.
B. unidirectional radiation pattern in the vertical plane
8799.
C. omnidirectional radiation pattern in the horizontal plane
8800.
D. a bidirectional radiation pattern in the horizontal plane
8801.
8802.
68. In order to get maximum radiation to all surrounding points in the horizontal
plane, the antenna used is a
8803.
A. vertical loop
8804.
B. vertical quarter-wavelength rod
8805.
C. array which includes parasitic elements
8806.
D. a horizontal Hertz dipole
8807.
8808.
69. What is the electrical wavelength of a 500 MHz signal?
8809.
A. 60 centimeters
8810.
B. 6 meters
8811.
C. 0.06 meter
8812.
D. 60 meters
8813.
8814.
70. If the antenna current is doubled, the field strength at a particular position is
8815.
A. doubled
8816.
B. halved
8817.
C. multiplied by a factor of four
8818.
D. divided by a factor of four
8819.

8820.
8821.
71. The rhombic antenna is primarily used for
8822.
A. ground wave propagation
8823.
B. space wave propagation
8824.
C. ionosphere scatter propagation
8825.
D. sky wave propagation
8826.
8827.
72. What antenna radiates equally in all directions?
8828.
A. Vertical antenna
8829.
B. isotropic antenna
8830.
C. Horizontal antenna
8831.
D. Dipole antenna
8832.
8833.
73. Actual height of antenna should be at least
8834.
A. one wavelength
8835.
B. half wavelength
8836.
C. quarter wavelength
8837.
D. three-fourth wavelength
8838.
8839.
74. Which antenna is not properly terminated?
8840.
A. Resonant
8841.
B. Non-resonant
8842.
C. Isotropic
8843.
D. Whip
8844.
8845.
75. ______ is an antenna array which is highly directional at right angles to the
plane of the array?
8846.
A. Broadside array
8847.
B. End-fire array
8848.
C. Turnstile array
8849.
D. Log-periodic array
8850.
8851.
76. The directivity pattern of an isotropic radiator is
8852.
A. a figure-8
8853.
B. a sphere
8854.
C. a unidirectional cardioid
8855.
D. a parabola
8856.
8857.
77. An isotropic radiator is
8858.
A. in the northern hemisphere
8859.
B. an antenna high enough in the air
8860.
C. an antenna whose directive pattern is substantially incredible
8861.
D. a hypothetical, omnidirectional antenna
8862.
8863.
8864.

8865.
8866.
78. The purpose of stacking elements on an antenna.
8867.
A. Sharper directional pattern
8868.
B. increased gain
8869.
C. Improved bandpass
8870.
D. All of these
8871.
8872.
79. The advantage of using top loading in a shortened HF vertical antenna is
8873.
A. lower quality factor
8874.
B. greater structural strength
8875.
C. higher losses
8876.
D. improved radiation efficiency
8877.
8878.
80. Where are the voltage nodes in a half-wave antenna?
8879.
A. At the ends
8880.
B. Three-quarters of the way from the feed point toward the end
8881.
C. One-half of the way from the feed point toward the end
8882.
D. At the feed point
8883.
8884.
81. A theoretical reference antenna that provides a comparison for antenna
measurements.
8885.
A. Marconi antenna
8886.
B. Isotropic radiator
8887.
C. Yagi-Uda array
8888.
D. Whip antenna
8889.
8890.
82. A Hertz antenna is operating on a frequency of 2182 kHz and consists of a
horizontal wire that is hanged between two towers. What is the frequency of its third
harmonic?
8891.
A. 727 kHz
8892.
B. 6546 kHz
8893.
C. 436 kHz
8894.
D. 6.546 kHz
8895.
8896.
83. In horizontal-dipole antenna, the polarization is
8897.
A. in the vertical direction
8898.
B. in the horizontal direction
8899.
C. circular
8900.
D. measured at the center of the antenna
8901.
8902.
84. Increasing the electrical length of an antenna means
8903.
A. add an inductor in parallel
8904.
B. add a capacitor in series
8905.
C. add an inductor series
8906.
D. add a resistor is series
8907.

8908.
8909.
8910.
8911.
85. Stacking antennas at various angles results in
8912.
A. a more omnidirectional reception
8913.
B. a more unidirectional reception
8914.
C. a more omnidirectional reception
8915.
D. an overall reception signal increase
8916.
8917.
86. What is driven element?
8918.
A. Always the rearmost element
8919.
B. Always the forward most element
8920.
C. The element fed by the transmission line
8921.
D. The element connected to the rotator
8922.
8923.
87. What is antenna bandwidth?
8924.
A. Antenna length divided by the number of elements
8925.
B. The angle between the half-power radiation points
8926.
C. The angle formed between two imaginary lines drawn through
8927.
D. The frequency range over which an antenna can be expected to
operate satisfactorily
8928.
8929.
88. To lengthen an antenna electrically, add a
8930.
A. resistor
8931.
B. battery
8932.
C. condult
8933.
D. coil
8934.
8935.
89. What is the gain of an antenna over a half-wavelength dipole when it has 6 dB
gain over an isotropic radiator?
8936.
A. 6.0 dB
8937.
B. 8.1 dB
8938.
C. 3.9 dB
8939.
D. 10.0 dB
8940.
8941.
90. What is the usual electrical length of a driven element in an HF beam
antenna?
8942.
A. ¼ wavelength
8943.
B. ¾ wavelength
8944.
C. ½ wavelength
8945.
D. 1 wavelength
8946.
8947.
91. What happens to the bandwidth of an antenna as it is shortened through the
use of loading coils?
8948.
A. It is increased
8949.
B. It is decreased

8950.
8951.
8952.
8953.
8954.
8955.
8956.
8957.
8958.
8959.
8960.
8961.
8962.
8963.
8964.
8965.
8966.
8967.
8968.
8969.
8970.
8971.
8972.
8973.
8974.
8975.
8976.
8977.
8978.
8979.
8980.
8981.
8982.
8983.
8984.
8985.
8986.
8987.
8988.
8989.
8990.
8991.
8992.
8993.
8994.
8995.

C. No change occurs
D. It becomes flat

92. To electrically decrease the length of an antenna.
A. add an inductor in series
B. add an inductor in parallel
C. add a resistor in series
D. add a capacitor in series
93. Strong interference from one particular station can be eliminated by the use of
A. noise limiters
B. squelch circuits
C. negative feedback
D. wave traps in the antenna circuitry
94. It is useful to refer to an isotropic radiator.
A. when comparing the gains of directional antennas
B. when testing a transmission line for standing wave ratio
C. when (in the northern hemisphere) directing the transmission
D. when using a dummy load to tune a transmitter
95. A disadvantage of using a trap antenna.
A. It will radiate harmonics
B. It can only be used for single-bad operation
C. It is too sharply directional at lower frequencies
D. It must be neutralized
96. The input terminal impedance at the center of a folded dipole antenna is
A. 72 Ω
B. 300 Ω
C. 50 Ω
D. 73 Ω
97. When a capacitor is connected in series with a Marconi antenna?
A. Antenna open circuit stops transmission
B. An inductor of equal value must be added
C. No change occurs to antenna
D. Antenna resonant frequency increases
98. Where are the current nodes in a half-wave antenna?
A. At the ends
B. At the center
C. Three-quarters of the way from the feed point toward the end
D. One-half of the way from the feed point toward the end

8996.
8997.
8998.
8999.
9000.
99. For a shortened vertical antenna, where should a loading coil be placed to
minimize losses and produce the most effective performance?
9001.
A. As low as possible on the vertical radiator
9002.
B. Near the center of the vertical radiator
9003.
C. As close to the transmitter as possible
9004.
D. At a voltage node
9005.
9006.
100. The effect of adding parasitic elements of a Hertz dipole is to
9007.
A. make the antenna more omnidirectional
9008.
B. reduce its resonant frequency
9009.
C. increase the antenna’s power gain
9010.
D. All of these
9011.
9012.
101. Stacking antenna elements
9013.
A. increases sensitivity to weak signals
9014.
B. will suppress odd harmonics
9015.
C. decrease signal to noise ratio
9016.
D. increases selectivity
9017.
9018.
102. In the case if Marconi antenna, the actual length if the radiating element is
9019.
A. one-half wavelength
9020.
B. one-quarter wavelength
9021.
C. one wavelength
9022.
D. one-eight wavelength
9023.
9024.
103. The antenna efficiency of an HF grounded vertical antenna can be made
comparable to that of a half-wave antenna
9025.
A. By installing a good ground radial system
9026.
B. By isolating the coax shield from ground
9027.
C. By shortening the vertical
9028.
D. By lengthening the vertical
9029.
9030.
104. An antenna “efficiency” is computed by using one of the following
equations.
9031.
A. Efficiency = (radiation resistance / transmission resistance)
9032.
B. Efficiency = (total resistance / radiation resistance) x 100%
9033.
C. Efficiency = (effective radiated power / transmitter output) x 100%
9034.
D. Efficiency = (radiation resistance / total resistance) x 100%
9035.
9036.
105. Increasing the resonant frequency of an end-fed Marconi antenna can be
done by
9037.
A. adding a capacitor in series and reducing the physical length

9038.
B. adding an inductor in series
9039.
C. adding an inductor in series
9040.
D. All of these
9041.
9042.
9043.
9044.
106. Factors that determine the radiation resistance of an antenna
9045.
A. Transmission line length and height of antenna
9046.
B. The location of the antenna with respect to nearby objects
9047.
C. It is a constant for all antennas since it is physical
9048.
D. Sunspot activity and the time of day
9049.
9050.
107. _____ is the angle between the half-power radiation points
9051.
A. Critical angle
9052.
B. Beamwidth
9053.
C. Angle of elevation
9054.
D. Azimuth
9055.
9056.
108. What is the ratio of the maximum radiation intensity to the average radiation
intensity?
9057.
A. Aperture gain
9058.
B. Directivity gain
9059.
C. Transmission gain
9060.
D. Power gain
9061.
9062.
109. Good grounding is important for
9063.
A. horizontal antennas
9064.
B. broadside array antennas
9065.
C. vertical antennas
9066.
D. Yagi-Uda antennas
9067.
9068.
110. An ungrounded antenna near the ground
9069.
A. acts as a single antenna of twice the height
9070.
B. is unlikely to need an earth mat
9071.
C. acts as antenna array
9072.
D. must be horizontally polarized
9073.
9074.
111. One of the following is very useful as a multiband HF receiving antenna.
9075.
A. Parabolic antenna
9076.
B. Elementary doublet
9077.
C. Log-periodic
9078.
D. Square loop
9079.
9080.
112. Which of the following antennas is best excited from a waveguide?
9081.
A. Biconical
9082.
B. Horn

9083.
C. Helical
9084.
D. Discone
9085.
9086.
9087.
9088.
9089.
9090.
113. Indicate which of the following reasons for using metal counterpoise with
antennas is false.
9091.
A. Impossibly of a good ground connection
9092.
B. Protection of personnel working underneath
9093.
C. Provision of an earth for the antenna
9094.
D. Rockiness of the ground itself
9095.
9096.
114. Not a reason for the use of an antenna coupler.
9097.
A. To make the antenna look resistive
9098.
B. To provide the output amplifier with the correct load impedance
9099.
C. To discriminate against harmonics
9100.
D. To prevent re-radiation of the local oscillator
9101.
9102.
115. Which antenna is not a wideband?
9103.
A. Discone
9104.
B. Folded dipole
9105.
C. Helical
9106.
D. Marconi
9107.
9108.
116. One of the following is not a reason for the use of an earth mat
9109.
A. impossibility of a good ground connection
9110.
B. provision of an earth for the antenna
9111.
C. protection of personnel working underneath
9112.
D. improvement of the radiation pattern of the antenna
9113.
9114.
117. One of the following makes an antenna physically long but electrically short
9115.
A. Adding L in series
9116.
B. Adding C in series
9117.
C. Top loading
9118.
D. Both A and C
9119.
9120.
118. When antennas are closed to the ground, _______ polarization is ideal
9121.
A. horizontally polarized
9122.
B. vertically polarized
9123.
C. circularly polarized
9124.
D. both A and B
9125.
9126.
119. _____ is an antenna made up of a number of full wavelengths
9127.
A. Elementary doublet

9128.
B. Log-periodic
9129.
C. Long wire
9130.
D. Whip
9131.
9132.
9133.
9134.
9135.
120. Any energy which radiates in the form of radio waves, infrared waves, light
waves, x-rays, etc.
9136.
A. Radiant energy
9137.
B. Electromagnetic
9138.
C. Heat
9139.
D. Ultraviolet
9140.
9141.
121. Which one is an antenna coupling unit?
9142.
A. Coupler
9143.
B. Diplexer
9144.
C. Lecher wire
9145.
D. Duplexer
9146.
9147.
122. _____ polarization is employed in AM broadcasting
9148.
A. Horizontal
9149.
B. Vertical
9150.
C. Circular
9151.
D. Omnidirectional
9152.
9153.
123. ______ polarization is employed in FM broadcasting
9154.
A. Horizontal
9155.
B. Vertical
9156.
C. Circular
9157.
D. Bidirectional
9158.
9159.
124. Which antenna is not grounded at one end?
9160.
A. Hertz
9161.
B. Marconi
9162.
C. Dipole
9163.
D. Whip
9164.
9165.
125. Which antenna does not use the ground?
9166.
A. Marconi
9167.
B. Yagi
9168.
C. Hertz
9169.
D. Rhombic
9170.
9171.
9172.

9173.
9174.
9175.
9176.
9177.
9178.
9179.

OPTICAL FIBER COMMUNICATIONS

9180.

Founded the wave theory of light

9181. Francesco Grimaldi
9182. Edward Appleton
9183. James Clerk Maxwell
9184. Christian Huygens
9185.
9186.

Proposed the use of clad glass fiber as a dielectric waveguide

9187. Karpon and Keck
9188. Karpon and Bockham
9189. Bockham and Kao
9190. Kao and Keck
9191.
9192.

Developed the first laser

9193. Charles Townes
9194. Theodore Maiman
9195. Gordon McKenzie
9196. Albert Einstein
9197.
9198.

The band of light wavelengths that are too long to be seen by the human eye

9199. Amber
9200. Visible
9201. Infrared
9202. Ultraviolet
9203.
9204.

The band of light wavelengths that are too short to be seen by the human eye

9205. Amber
9206. Visible
9207. Infrared
9208. Ultraviolet
9209.
9210.

Which color has the shortest wavelength of light?

9211. Red
9212. Yellow
9213. Blue
9214. Green
9215.
9216.

What generates a light beam of a specific visible frequency?

9217. Laser
9218. Maser
9219. Infrared
9220. Flashlight
9221.

9222.

Which of the following materials is sensitive to light?

9223. Photoresist
9224. Photosensitive
9225. Light Sensitive
9226. Maser
9227.
9228.

The core of an optical fiber has a

9229. Lower refracted index than air
9230. Lower refractive index than the cladding
9231. Higher refractive index than the cladding
9232. Similar refractive index with the cladding
9233.
9234.
Is the different angle of entry of light into an optical fiber when the diameter of
the core is many times the wavelength of the light transmitted.
9235. Acceptance angle
9236. Modes
9237. Sensors
9238. Aperture
9239.
9240.

The loss in signal power as light travels down a fiber is called

9241. Dispersion
9242. Scattering
9243. Absorption
9244. Attenuation

9245.
9246.

The bandwidth of optical fiber

9247. 900MHz
9248. 900PHz
9249. 900THz
9250. 900EHz
9251.
9252.
If a mirror is used to reflect light, the reflected light angle is ____ as the incident
angle
9253. Smaller
9254. Larger
9255. The same
9256. Independent
9257.
9258.
9259.
9260.
What is a specific path the light takes in an optical fiber corresponding to a certain
angle and number of reflection
9261. Mode
9262. Grade
9263. Numerical Aperture
9264. Dispersion
9265.
9266.

9267.
9268.

Is the width of the range of wavelengths emitted by the light source

9269. Bandwidth
9270. Chromatic Dispersion
9271. Spectral width
9272. Beamwidth
9273.
9274.
Which theory states that the light wave behaves as if it consists of many tiny
particles?
9275. Huygen’s theory
9276. Wave theory of light
9277. Nyquist theory
9278. Quantum theory
9279.
9280.

Fiber optic cables operate at frequencies near

9281. 20MHz
9282. 200MHz
9283. 2GHz
9284. 800THz
9285.
9286.
When a beam of light enters one medium from another, which quantity will not
change?
9287. Direction
9288. Speed

9289. Frequency
9290. Wavelength
9291.
9292.

Dispersion is used to describe the

9293. Splitting of white light into its component colors
9294. Propagation of light in straight lines
9295. Bending of a beam of light when it goes from one medium to another
9296. Bending of a beam light when it strikes a mirror
9297.
9298.

Luminance efficiency is minimum for a

9299. Fluorescent tube
9300. High wattage light bulb
9301. Mercury vapor lamp
9302. Low wattage light bulb
9303.
9304.
An object farther from a converging lens than its focal point always has a/an
_____ image.
9305. Inverted
9306. The same in size
9307. Virtual
9308. Smaller size
9309.
9310.
An object nearer to a converging lens than its focal point always has a/an ______
image.

9311. Inverted
9312. The same in size
9313. Virtual
9314. Smaller size
9315.
9316.

The real image formed by a spherical mirror is ____ relative to its object

9317. Erect
9318. Inverted
9319. Smaller
9320. Larger
9321.
9322.
9323.

The wavelength of light has no role in

9324. Diffraction
9325. Interference
9326. Polarization
9327. Reflection
9328.
9329.

Longitudinal waves do not exhibit

9330. Polarization
9331. Refraction
9332. Reflection
9333. Diffraction

9334.
9335.
________ dispersion is caused by the difference in the propagation times of light
rays that take different paths down a fiber.
9336. Material dispersion
9337. Wavelength dispersion
9338. Modal dispersion
9339. Delay dispersion
9340.
9341.

What is the average insertion loss of fusion splice in fiber optics?

9342. 0.09dB
9343. 0.9dB
9344. 0.19dB
9345. 0.009dB
9346.
9347.

What is the insertion loss of connector-type splices for a single mode fiber optics?

9348. 0.51dB
9349. 0.31dB
9350. 0.49dB
9351. 0.38dB
9352.
9353.

What is the lifetime of LEDs?

9354. 200,000 minutes
9355. 200,000 hours
9356. 150,000 minutes

9357. 150,000 hours
9358.
9359.

What is the lifetime of ILDs?

9360. 50,000 hours
9361. 75,000 hours
9362. 100,000 hours
9363. 125,000 hours
9364.
9365.
Photodiodes used as fiber optic directors are
9366. Unbiased to generate a voltage same as a solar cell
9367. Forward bias
9368. Reversed bias
9369. Thermoelectrically cooled
9370.
9371.
9372.
What type of fiber has the highest modal dispersion?
9373. Step-index multimode
9374. Graded index multimode
9375. Step-index single mode
9376. Graded index mode
9377.
9378.
9379.
Laser light is ______ emission.
9380. Coherent
9381. Stimulated
9382. Spontaneous
9383. Coherent and stimulated
9384.
9385.
9386.
A dielectric waveguide for the propagation of electromagnetic energy at light
frequencies
9387. Stripline
9388. Microstrip
9389. Laser beam
9390. Fiber optics
9391.
9392.
9393.
Is a non-coherent light source foe optical communications system.
9394. ILD

9395. LED
9396. APD
9397. PIN Diode
9398.
9399.
9400.
Which type of laser is the simplest to modulate directly by changing its
excitation?
9401. Semiconductor
9402. Ruby
9403. Helium-neon
9404. Neodymium-YAG
9405.
9406.
9407.
Which laser emits light in the visible range 400 to 700 nm?
9408. Argon-ion
9409. Nitrogen
9410. Carbon-dioxide
9411. Neodymium-YAG
9412.
9413.
9414.
Which is the proper measurement of average power emitted by a pulsed laser?
9415. Energy x time
9416. Pulse energy x repetition rate
9417. Pulse energy / repetition rate
9418. Peak power x pulse length
9419.
9420.
9421.
What is the photon energy for an infrared wave with frequency of 1012 Hz?
9422. 10.6 x 1034 joules
9423. 6.63 x 10-34 joules
9424. 6.63 x 10-22 joules
9425. 10.6 x 1022 joules
9426.
9427.
9428.
A positive lens with a focal length of 10 cm forms a real image of an object 20 am
away from the lens. How far is the real image from the lens?
9429. 5 cm
9430. 10 cm
9431. 15 cm
9432. 20 cm
9433.
9434.
9435.
Which of the following factor does not harm laser efficiency?
9436. Atmospheric absorption
9437. Excitation energy not absorbed
9438. Problems in depopulating the lower laser level

9439. Inefficiency in populating the upper laser level
9440.
9441.
9442.
Which of the following contributes to the broadening of laser emission
bandwidth?
9443. Doppler shift of moving atoms and molecules
9444. Amplification within the laser medium
9445. Coherence of the laser light
9446. Optical pumping of the laser transition
9447.
9448.
9449.
The first laser emitted
9450. Pulses of 694 nm red light
9451. A continuous red beam
9452. Pulses of white light from a helical flashlamp
9453. Spontaneous emission
9454.
9455.
9456.
What is the stage of the sand becoming a silicon?
9457. Liquid
9458. Gas
9459. Molten
9460. Hot
9461.
9462.
9463.
Which of the following is used as an optical transmitter on the Fiber Optical
Communications?
9464. APD
9465. LSA diode
9466. PIN diode
9467. LED
9468.
9469.
9470.
Which of the following is used as an optical receiver in fiber optics
communications
9471. APD
9472. Tunnel diode
9473. Laser diode
9474. LED
9475.
9476.
9477.
The numerical aperture of a fiber if the angle of acceptance is 15 degrees, is
9478. 017
9479. 0.26
9480. 0.50
9481. 0.75

9482.
9483.
9484.
The inner portion of the fiber cable is called
9485. Cladding
9486. Coating
9487. Inner conductor
9488. Core
9489.
9490.
9491.
Which type of laser is the simplest to modulate directly by changing its
excitation?
9492. Semiconductor
9493. Ruby
9494. Helium-neon
9495. Neodymium-YAG
9496.
9497.
9498.
The laser frequency when the light has the wavelength 800 nm is
9499. 375 x 10^12 Hz
9500. 475 x 10^15 Hz
9501. 375 x 10^9 Hz
9502. 375 x 10^18 Hz
9503.
9504.
9505.
Which of the following is not a common application of fiber-optic cable?
9506. Computer networks
9507. Long-distance telephone systems
9508. Closed circuit TV
9509. Consumer TV
9510.
9511.
9512.
Total internal reflection takes place if the light ray strikes the interface at an angle
with what relationship to the critical angle?
9513. Less than
9514. Grater than
9515. Equal to
9516. Zero
9517.
9518.
9519.
The operation of the fiber-optic cable is based on the principle of
9520. Refraction
9521. Reflection
9522. Dispersion
9523. Absorption
9524.
9525.

9526.
9527.
9528.
9529.
9530.
9531.
9532.
9533.
9534.
9535.
9536.
9537.
9538.
9539.
9540.
9541.
9542.
9543.
9544.
9545.
9546.
9547.
9548.
9549.
9550.
9551.
9552.
9553.
9554.
9555.
9556.
9557.
9558.
9559.
9560.
9561.
9562.
9563.
9564.
9565.
9566.
9567.
9568.
9569.
9570.
9571.

Which of the following is not a common type of fiber-optic cable?
Single-mode step-index
Multimode graded-index
Single-mode graded-index
Multimode step-index
Cable attenuation is usually expressed in terms of
Loss per foot
dB/km
intensity per mile
voltage drop per inch
Which of the cable length has the highest attenuation?
1 km
2 km
95 ft
5500 ft
The upper pulse rate and information carrying capacity of a cable is limited by
Pulse shortening
Attenuation
Light leakage
Modal dispersion
The core of a fiber optic cable is made of
Air
Glass
Diamond
Quartz
The core of a fiber optic is surrounded by
Wire braid shield
Kevlar
Cladding
Plastic insulation
The speed of light in plastic compared to the speed of light in air is
Slower
Faster
The same
Either lower or faster

9572.
9573.
9574.
Which of the following is not a major benefit of fiber-optic cable?
9575. Immunity from interference
9576. No electrical safety problems
9577. Excellent data security
9578. Lower cost
9579.
9580.
9581.
The main benefit of light-wave communications over microwaves or any other
communications media is
9582. Lower cost
9583. Better security
9584. Wider bandwidth
9585. Freedom from interference
9586.
9587.
9588.
Which of the following is not part of the optical spectrum?
9589. Infrafed
9590. Ultraviolet
9591. Visible color
9592. X-rays
9593.
9594.
9595.
The wavelength of visible light extends from
9596. 0.8 to 1.0 nm
9597. 400 to 750 nm
9598. 200 to 660 nm
9599. 700 to 1200 nm
9600.
9601.
9602.
The speed of light is
9603. 186,000 mi/h
9604. 300 mi/h
9605. 300,000 m/s
9606. 300,000,000 m/s
9607.
9608.
9609.
Refraction is the
9610. Bending of light waves
9611. Reflection of light waves
9612. Distortion of light waves
9613. Diffusion of light waves
9614.
9615.
9616.
The ratio of speed of light in air to the speed of light in another substance is called

the
9617.
9618.
9619.
9620.
9621.
9622.
9623.
9624.
9625.
9626.
9627.
9628.
9629.
9630.
9631.
9632.
9633.
9634.
9635.
9636.
9637.
9638.
9639.
9640.
9641.
9642.
9643.
9644.
9645.
9646.
9647.
9648.
9649.
9650.
9651.
9652.
9653.
9654.
9655.
9656.
9657.
9658.
9659.
9660.
9661.

Speed factor
Index of reflection
Index of refraction
Dielectric constant
A popular light wavelength in fiber-optic cable is
0.7 um
1.3 um
1.5 um
1.8 um
Which type of fiber optic cable is most widely used?
Single-mode step-index
Multimode step-index
Single-mode graded-index
Multimode graded-index
Which type of fiber-optic cable is the best for very high speed data?
Single-mode step-index
Multimode step-index
Single-mode graded-index
Multimode graded-index
Which type of fiber-optic cable has the least modal dispersion?
Single mode step-index
Multimode step-index
Single-mode graded-index
Multimode graded-index
Which of the following is not a factor in cable light loss?
Reflection
Absorption
Scattering
Dispersion
A distance of 8 km is the same as
2.5 mi
5 mi
8 mi

9662. 12.9 mi
9663.
9664.
9665.
A fiber-optic cable has a loss of 15 dB/km. The attenuation in a cable, 100 ft long
is
9666. 4.57 dB
9667. 9.3 dB
9668. 24 dB
9669. 49.2 dB
9670.
9671.
9672.
Fiber-optic cables with attenuations of 1.8, 3.4, 5.9, and 18 dB are linked together.
The total loss is
9673. 7.5 dB
9674. 19.8 dB
9675. 29.1 dB
9676. 650 dB
9677.
9678.
9679.
Which light emitter is preferred for high speed data in a fiber-optic system
9680. Incandescent
9681. LED
9682. Neon
9683. Laser
9684.
9685.
9686.
Most fiber-optic light sources emit light in which spectrum?
9687. Visible
9688. Infrared
9689. Ultraviolet
9690. X-ray
9691.
9692.
9693.
Both LEDs and ILDs operate correctly with
9694. Forward bias
9695. Reverse bias
9696. Neither A or B
9697. Either A or B
9698.
9699.
9700.
Single-frequency light is called
9701. Pure
9702. Intense
9703. Coherent
9704. Monochromatic
9705.

9706.
9707.
Laser light is very bright because it is
9708. Pure
9709. White
9710. Coherent
9711. Monochromatic
9712.
9713.
9714.
Which of the following is NOT a common light detector
9715. PIN photodiode
9716. Photovoltaic diode
9717. Photodiode
9718. Avalanche photodiode
9719.
9720.
9721.
Which of the following is the fastest light sensor
9722. PIN photodiode
9723. Photovoltaic diode
9724. Phototransistor
9725. Avalanche photodiode
9726.
9727.
9728.
Photodiodes operate property with
9729. Forward bias
9730. Reverse bias
9731. Neither A or B
9732. Either A or B
9733.
9734.
9735.
The product of the bit rate and distance of a fiber-optic system is 2 Gbits km/s.
What is the maximum rate at 5 km?
9736. 100 Mbits/s
9737. 200 Mbits/s
9738. 400 Mbits/s
9739. 1000 Gbits/s
9740.
9741.
9742.
Which fiber-optic system is better?
9743. 3 repeaters
9744. 8 repeaters
9745. 11 repeaters
9746. 20 repeaters
9747.
9748.
9749.
An important requirement for successful transmission system using light
9750. Powerful, reliable light source

9751.
9752.
9753.
9754.
9755.
9756.
9757.
9758.
9759.
9760.
9761.
9762.
9763.
9764.
9765.
9766.
9767.
9768.
9769.
9770.
9771.
9772.
9773.
9774.
9775.
9776.
9777.
9778.
9779.
9780.
9781.
9782.
9783.
9784.
9785.
9786.
9787.
9788.
9789.
9790.
9791.
9792.
9793.
9794.
9795.
9796.

Strong glass
Reliable, high cost transmission medium
Powerful regenerators
What is used to block light from a laser and let other light through
Neutral density
Color
Interference
Spatial
________ is a light that can be coherent
Spontaneous emission
Monochromatic and in-phase
Narrow beam divergence
Monochromatic
Coherence of laser light is important for _________
Light propagation
Getting laser light to pass through air
Drilling holes
Holography
The ultrapure glass used to manufacture optical fibers is approximately ___pure
99.9 %
99.99 %
99.999%
99.9999%
In fiber optics, PCS stands for
Plastic-clad-silica
Polyethylene-clad-silica
Personal carrier system
Personal communication
How many longitudinal modes can fall within a laser’s gain bandwidth?
2
5
9
No fixed limit, dependent on bandwidth and mode spacing

9797.
9798.
_________ is the result of photons of light that are absorbed by the atoms of the
glass core molecules
9799. Ion resonance absorption
9800. Ultraviolet absorption
9801. Infrared absorption
9802. Absorption loss
9803.
9804.
9805.
In fiber optics, SCS stands for
9806. Suppressed-clad-silicon
9807. Silicon base-class-silica
9808. Silica-clad-silica
9809. Serial-clad-silicon
9810.
9811.
9812.
Human laser was developed by A. Javen at Bell laboratory in
9813. 1960
9814. 1962
9815. 1963
9816. 1964
9817.
9818.
9819.
What parameter of light detector determines the range or system length that can
be achieved for a given wavelength?
9820. Transit time
9821. Spectral response
9822. Dark current
9823. Responsitivity
9824.
9825.
9826.
Dark current in light detectors is caused by
9827. Thermally generated carriers in the diode
9828. The absence of light input
9829. Small leakage current
9830. Its imperfection
9831.
9832.
9833.
What is the unit of responsitivity?
9834. Ampere/volt
9835. Ampere/watt
9836. Watt/ampere
9837. Volts/ampere
9838.
9839.
9840.
One of the following is not a characteristic of light detectors.

9841.
9842.
9843.
9844.
9845.
9846.
9847.
9848.
9849.
9850.
9851.
9852.
9853.
9854.
9855.
9856.
9857.
9858.
9859.
9860.
9861.
9862.
9863.
9864.
9865.
9866.
9867.
9868.
9869.
9870.
9871.
9872.
9873.
9874.
9875.
9876.
9877.
9878.
9879.
9880.
9881.
9882.
9883.
9884.
9885.
9886.

Responsitivity
Spectral response
Transmit time
Dispersion
What is the typical wavelength of light emitted from epitaxially grown LEDs?
840 nm
490 nm
480 nm
940 nm
SONET stands for
System Optical Network
Synchronous Optical Network
Silica Optic Network
System Optical Fiber Net
Band loss is
A reduction in transmitter power caused by earth’s surface curvature
A reduction in strength of the signal caused by folded dipole bends
An attenuation increase caused by bends radiating from the side of the fiber
All of these
Infrared range for fiber optics
400 – 700 nm
700 – 1200 nm
300 – 2000 nm
400 – 7000 nm
Which of the following is a disadvantage for plastic fiber optics?
Noise immunity
Electric hazards
Higher losses
All of these
OTDR stands for
Optical Time Domain Reflectometer
Optical Transmit Direction Return
Optical Time Domain Time Regeneration
Overtime Direct Reference

9887.
9888.
9889.
Which of the following is determined by an OTDR?
9890. Distance to trouble
9891. Length of fiber
9892. Refractive index
9893. All of these
9894.
9895.
9896.
Under normal condition, a single fiber should not be used for a two-way
communication mainly because of
9897. Loss
9898. Fading
9899. Noise
9900. Attenuation
9901.
9902.
9903.
A single mode optical fiber has a core diameter of _____ nm.
9904. 0.1
9905. 0.01
9906. 0.2
9907. 0.05
9908.
9909.
9910.
A step-index multimode optical fiber has a core diameter of _____ nm.
9911. 0.02
9912. 0.2
9913. 2
9914. 0.002
9915.
9916.
9917.
The graded-index multimode optical fiber has a core diameter of _____ nm.
9918. 0.5
9919. 0.05
9920. 0.0005
9921. 5
9922.
9923.
9924.
Which is not a possible cause of optical fiber loss?
9925. Impurities
9926. Glass attenuation
9927. Stepped index operation
9928. Microbending
9929.
9930.
9931.
The ratio of the speed of light in a vacuum and the speed of light in the material

used.
9932. S/N ratio
9933. Refractive index
9934. Intermodal dispersion
9935. Monomode ratio
9936.
9937.
9938.
Splicing fibers means
9939. Fusion
9940. Butt
9941. Glue
9942. Both fusion and butt
9943.
9944.
9945.
An IC that represents a short distance one-way optical communications
9946. Optoisolator
9947. Insulator
9948. Multivibrator
9949. Optical IC
9950.
9951.
9952.
When light strikes a flat polished end of a fiber, it produces a loss of
9953. 14 %
9954. 4 %
9955. 10 %
9956. 1 %
9957.
9958.
9959.
When light strikes a flat polished end of a fiber, the fiber loss produced can be
reduced by
9960. Splicing
9961. Antireflection coating
9962. Insulation jacket
9963. All of these
9964.
9965.
9966.
In fiber optics, higher-order mode refers to
9967. Cladding boundary at high angle
9968. Backscattering electromagnetic signals
9969. Diffracting signals
9970. All of these
9971.
9972.
9973.
9974.
The following are the cause of light attenuation in fiber optics except
9975. Backscattering

9976. Absorption
9977. Refraction
9978. Microbends
9979.
9980.
9981.
Why are visible-light LEDs not used for fiber optics?
9982. It has high losses
9983. It has short wave
9984. It has low attenuation
9985. It has weak signal
9986.
9987.
9988.
Optical cable testers are used for
9989. Checking refractive index
9990. Light power out of a fiber
9991. Non-calibrated light into a fiber
9992. Checking maximum distance covered
9993.
9994.
9995.
A function of an optic isolator
9996. Cancels reflective waves
9997. Amplifies signal transmitted
9998. Filters unnecessary signals
9999. All of these
10000.
10001.
10002.
An increase in light intensity produces fast optic switching due to
10003. Increase in index of glass
10004. Amplification of optical signal
10005. High gain
10006. Photoconductivity
10007.
10008.
10009.
Light traveling in optical fiber follows which of the following principles.
10010. Huygen’s principle
10011. Reflection theory
10012. Light theory
10013. Snell;s law
10014.
10015.
10016.
Optical fibers for telecommunications are typically about _____ mils thick and
consists of a glass core, a glass cladding of lower index of refraction, and a protective
coating
10017. 5
10018. 6
10019. 7

10020. 8
10021.
10022.
10023.
Material dispersion is caused by the
10024. Wavelength dependence of the index of refraction
10025. Wavelength independence of the index of refraction
10026. Dependence of the propagation constant on the mode number
10027. Independence of the propagation constant on the mode number
10028.
10029.
10030.
Modal dispersion is caused by the
10031. Dependence of wavelength on index of refraction
10032. Dependence of propagation constant on index of refraction
10033. Dependence of the propagation constant on the wavelength
10034. Dependence of the propagation constant on the mode number
10035.
10036.
10037.
The dominant loss mechanisms in silica fiber are
10038. Absorption and radiation losses
10039. Absorption and Rayleigh scattering
10040. Coupling and radiation losses
10041. Radiation and modal dispersion
10042.
10043.
10044.
The bandwidth of a fiber is limited by
10045. Mode
10046. Wavelength
10047. Dispersion
10048. Frequency
10049.
10050.
10051.
Fiber bandwidth is generally specified as the
10052. Product of the bandwidth and distance
10053. Sum of the bandwidth and distance
10054. Difference of the bandwidth and distance
10055. Quotient of bandwidth and distance
10056.
10057.
10058.
The _____ of a detector is the fraction of incident photons that produce a
photoelectron or electron-hole pair
10059. Responsitivity
10060. Photon efficiency
10061. Aperture
10062. Quantum efficiency
10063.
10064.

10065.
In solid-state optical detectors, the excited charge is transported in the solid by
10066. Holes and protons
10067. Holes and electrons
10068. Anion and cation
10069. Protons and photons
10070.
10071.
10072.
One of the following is not a solid-state optical detector
10073. APD
10074. PIN
10075. PMT
10076. Phototransistors
10077.
10078.
10079.
Optical detectors are square-law devices because they respond to _____ rather
than amplitude
10080. Intensity
10081. Light
10082. Density
10083. Photon
10084.
10085.
10086.
The _____ is equal to the number of electrons emitted per second times the
electron charge
10087. Intensity
10088. Optical power
10089. Photocurrent
10090. Responsitivity
10091.
10092.
10093.
Which optical detector is used when high sensitivity and bandwidth are required?
10094. PMT
10095. APD
10096. PIN
10097. Phototransistor
10098.
10099.
10100.
What is the average loss in fiber splice?
10101. 0.10 dB
10102. 0.15 dB
10103. 0.20 dB
10104. 0.25 dB
10105.
10106.
10107.
Which of the following colors is not found in the visible light wave spectrum?
10108. Red

10109. White
10110. Orange
10111. Yellow
10112.
10113.
10114.
What is the frequency limit of an optical fiber?
10115. 20 GHz
10116. 30 GHz
10117. 40 GHz
10118. 50 GHz
10119.
10120.
10121.
The mechanical splice attenuation loss is _____ dB or less
10122. 0.1
10123. 0.01
10124. 0.001
10125. 1
10126.
10127.
10128.
_____ is applied to protect core and cladding of the fiber
10129. Insulation
10130. Fiber insulation
10131. Silica
10132. Polymer jacket
10133.
10134.
10135.
The energy of the photon is
10136. Directly proportional to its bandwidth
10137. Directly proportional to the Planck’s constant
10138. Directly proportional to Boltzmann’s constant
10139. Inversely proportional to the Planck’s constant
10140.
10141.
10142.
Refractive index of glass
10143. 1.0
10144. 1.2
10145. 1.4
10146. 1.5
10147.
10148.
10149.
Refractive index of diamond
10150. 1.0
10151. 1.4
10152. 1.8
10153. 2.0
10154.

10155.
10156.
What is the unit of light wavelength?
10157. Micrometer
10158. Angstroms
10159. Mils
10160. Fathom
10161.
10162.
10163.
How much is the power loss of the fusion splice?
10164. 0.1 dB or less
10165. 0.01 dB or less
10166. 1 dB or less
10167. 10 dB or less
10168.
10169.
10170.
Used to test a fiber optics splice
10171. Spectrum analyzer
10172. Oscilloscope
10173. Optical power meter
10174. Field strength meter
10175.
10176.
10177.
A coupler which consists of a series of lenses and a partly reflective surface
10178. Beam-splitting coupler
10179. Reflective star coupler
10180. Fused coupler
10181. None of these
10182.
10183.
10184.
Reflections in many directions
10185. Diffuse reflection
10186. Diffraction
10187. Scattering
10188. Dispersion
10189.
10190.
10191.
Commonly used electro-optic crystal for polarization modulation
10192. Lithium Niobate
10193. Tourmaline
10194. Sodium Chlorate
10195. Sphalerite
10196.
10197.
10198.
Which modulation methods are the most widely used in optical systems?
10199. Phase and frequency modulations
10200. Polarization modulation and phase modulation

10201. Intensity modulation and phase modulation
10202. Intensity modulation and polarization modulation
10203.
10204.
10205.
10206.
10207.
10208.
10209. BROADCASTING
10210.
10211.
10212. Which of the following is the first component of any MATV system to receive
broadcast signals?
10213.
Filter
10214.
LNA
10215.
RF amplifier
10216.
Antenna
10217.
10218.
10219. Is the most common technique where apartment house, hotels, schools,
condominiums, and multi-unit buildings distribute TV and FM signals to a number of
receivers, using a single head-end.
10220.
CCTV
10221.
CATV
10222.
MATV
10223.
Antenna
10224.
10225.
10226. TV channel 2, 4 and 5 belong to
10227.
Low band UHF
10228.
High band VHF
10229.
Mid band UHF
10230.
Low band VHF
10231.
10232.
10233. A mechanism or device which enables the TV camera to move in lateral and
tilting motion
10234.
Panning device
10235.
Scanner
10236.
Tilting
10237.
Pan/tilt device
10238.
10239.
10240. Which of the following is a solid state imaging device?
10241.
VIDICON
10242.
ICONOSCOPE

10243.
10244.

Charge couple device
CCTV

10245.
10246.
10247. What class of TV camera lens used to cover short distances?
10248.
Normal
10249.
Wide angle
10250.
Telephoto
10251.
Zoom
10252.
10253.
10254. What class of TV camera lens used to cover long distances?
10255.
Normal
10256.
Wide angle
10257.
Telephoto
10258.
Zoom
10259.
10260.
10261. What is the local oscillator frequency in commercial AM broadcast if it is equal to
455 kHz?
10262.
0 to 1500 kHz
10263.
0 to 455 kHz
10264.
540 to 1600 kHz
10265.
955 to 2055 kHz
10266.
10267.
10268. What is the allowable deviation ratio of commercial FM broadcast?
10269.
20
10270.
75
10271.
5
10272.
25
10273.
10274.
10275. The maximum power suggested by KBP on 919-1312 AM broadcast station in
Metro Manila is
10276.
5 kW
10277.
10 kW
10278.
15 kW
10279.
20 kW
10280.
10281.
10282. KBP radio code mandates that station must provide a minimum of ___ minutes
10283.
30
10284.
45
10285.
50
10286.
60

10287.
10288.
10289. What is the chroma subcarrier signal frequency for color television?
10290.
3.8 MHz
10291.
6.8 MHz
10292.
7.8 MHz
10293.
8.8 MHz
10294.
10295.
10296. What is the frequency tolerance of an FM Radio Broadcast station?
10297.
± 20000 Hz
10298.
± 20 Hz
10299.
± 200 Hz
10300.
± 2000 Hz
10301.
10302.
10303. The minimum frequency separation between frequency of AM broadcasting
station
10304.
9 kHz
10305.
18 kHz
10306.
36 kHz
10307.
72 kHz
10308.
10309.
10310.
10311.
10312. The aspect ratio HDTV is
10313.
4:3
10314.
18:5
10315.
14:8
10316.
16:9
10317.
10318.
10319. A newscast is a distinct unit of a program with a minimum news content of _____
minute(s) excluding intro, extro, headline and commercial load
10320.
1
10321.
2
10322.
3
10323.
4
10324.
10325.
10326. In accordance with existing provision of law and the KBP rules and the
regulations, all stations shall actively promote the growth ands the development of
Filipino music by playing _____ OPM every clock hour.
10327.
1
10328.
2

10329.
10330.

3
4

10331.
10332.
10333. Commercial load for radio shall not exceed ____ minutes for a one-hour program
outside Metro Manila
10334.
15
10335.
20
10336.
25
10337.
30
10338.
10339.
10340. Commercial load for radio shall not exceed _____ minutes for a one-hour
program outside Metro Manila.
10341.
15
10342.
16
10343.
17
10344.
20
10345.
10346.
10347. Program interruption for airing of commercial in Metro Manila shall not exceed
_____ breaks in every program hour
10348.
5
10349.
6
10350.
7
10351.
8
10352.
10353.
10354. Program interruption for the airing of commercial outside Metro Manila shall not
exceed _____ breaks in every program hour
10355.
5
10356.
6
10357.
7
10358.
8
10359.
10360.
10361. For Metro manila, the classification of prime time blocks for FM shall be
10362.
6:00 AM to 8:00 PM
10363.
6:00 AM to 12:00 NN
10364.
6:00 AM to 6:00 PM
10365.
12:00 NN to 12:00 MN
10366.
10367.
10368. For provincial station, the classification of prime time blocks for FM radio shall
be
10369.
6:00 AM to 8:00 PM

10370.
10371.
10372.

6:00 AM to 12:00 NN
6:00 AM to 6:00 PM
12:00 NN to 12:00 MN

10373.
10374.
10375. All airtime classifications shall be submitted to and subject for approval by the
10376.
NTC
10377.
KBP-SA
10378.
DOTC
10379.
CCITT
10380. _____ is the time circulation for one horizontal trace
10381.
52 us
10382.
62 us
10383.
48 us
10384.
50 us
10385.
10386.
10387. Listing of the date and time of events, programs, equipment, tests, malfunctions
and corrections in communications system.
10388.
Reporting
10389.
Documentation
10390.
Log
10391.
File
10392.
10393.
10394. Which of the following is not a low impedance microphone?
10395.
Dynamic
10396.
Velocity
10397.
Condenser
10398.
Crystal
10399.
10400.
10401. Facsimile permits remote duplications of which of the following items?
10402.
Map
10403.
Pictures
10404.
Printed page
10405.
All of these
10406.
10407.
10408. Television has a lot of features in common with
10409.
FM stereo
10410.
Telephone service
10411.
Motion picture
10412.
Magazine
10413.
10414.

10415. The major component of the TV signal waveform is the
10416.
Video
10417.
Radar
10418.
Stereo
10419.
Antenna
10420.
10421.
10422. For NTSC TV system, the image is scanned from
10423.
Top to bottom
10424.
Left to right
10425.
Right to left
10426.
Choices A and B above
10427.
10428.
10429. One completes NTSC scanning cycle called field consists of how many lines
10430.
500
10431.
525
10432.
625
10433.
60
10434.
10435.
10436. The field rate in the NTSC television system
10437.
30 Hz
10438.
120 Hz
10439.
60 Hz
10440.
15.75 Hz
10441.
10442.
10443. What is the horizontal synchronous blanking pulse rate?
10444.
30 Hz
10445.
60 Hz
10446.
15.75Hz
10447.
120 Hz
10448.
10449.
10450. What is the vertical blanking pulse rate?
10451.
30 Hz
10452.
60 Hz
10453.
15.75 Hz
10454.
120 Hz
10455.
10456.
10457. The pulses riding on the vertical blanking pulse
10458.
Equalizing (sync) pulses
10459.
Serrated vertical sync pulses
10460.
Black level pulses

10461.

Choices A and B above

10462.
10463.
10464. Television camera pickup tube is called
10465.
Vidicon
10466.
Image orthicon
10467.
Plumbicon
10468.
All of the above
10469.
10470.
10471. The television picture tube magnetic fields can be used for
10472.
Beam focusing
10473.
Beam deflection
10474.
Beam production
10475.
Beam modulation
10476.
10477.
10478. What is the purpose of an indirectly-heated cathode in a cathode ray tube?
10479.
Beam focusing
10480.
Beam deflection
10481.
Beam production
10482.
Beam modulation
10483.
10484.
10485. Video modulation for television is
10486.
Amplitude modulation
10487.
Frequency modulation
10488.
Vestigial sideband
10489.
Both amplitude modulation and vestigial sideband
10490.
10491.
10492. Audio modulation for television is
10493.
Amplitude modulation
10494.
Frequency modulation
10495.
Vestigial sideband
10496.
Both amplitude modulation and vestigial sideband
10497.
10498.
10499. What is the maximum frequency deviation for audio modulation in TV
transmission?
10500.
25 kHz
10501.
30 kHz
10502.
50 kHz
10503.
75 kHz
10504.
10505.

10506. The video carrier and the audio carrier are separated by ____ MHz.
10507.
4.5
10508.
5.5
10509.
6.5
10510.
7.5
10511.
10512.
10513. In a practical image scanned at the NTSC rate, the spectrum will include
components clustered at the fundamentals and harmonics of _____ kHz
10514.
15.75
10515.
30
10516.
12.25
10517.
45.5
10518.
10519.
10520. Brightness of an image is known as
10521.
Radiance
10522.
Chrominance
10523.
Reflectance
10524.
Luminance
10525.
10526.
10527. The colors at the vertices of the color triangle are referred to as
10528.
Primary
10529.
White
10530.
Desaturated
10531.
All of the above
10532.
10533.
10534. A color signal which originate in the camera itself with color television pickup?
10535.
Red
10536.
Green
10537.
Blue
10538.
All of these
10539.
10540.
10541. What are the three separate signals derived from a matrix in a color TV
transmitter?
10542.
Y, I and Q
10543.
P, D and Q
10544.
M, N and O
10545.
R, S and T
10546.
10547.
10548. Range of a VHF television transmitter
10549.
54 – 98 MHz

10550.
10551.
10552.

54 – 216 MHz
54 – 128 MHz
54 – 166 MHz

10553.
10554.
10555. Range of a UHF television transmitter
10556.
470 – 670 MHz
10557.
470 – 770 MHz
10558.
470 – 890 MHz
10559.
470 - 980 MHz
10560.
10561.
10562. What is the approximate bandwidth occupied by the chrominance video signal for
color TV?
10563.
0.8 MHz
10564.
1.8 MHz
10565.
8.1 MHz
10566.
1.6 MHz
10567.
10568.
10569. The colors found around the perimeter of the color triangle are said to be
10570.
Saturated
10571.
Dark
10572.
Light
10573.
Monochrome
10574.
10575.
10576. At what position on the color triangle will saturated yellow be located?
10577.
Between red and blue
10578.
Between red and green
10579.
Between blue and green
10580.
At the center
10581.
10582.
10583. What is the phase difference between the I and Q color signal carriers?
10584.

10585.
45°
10586.
60°
10587.
90°
10588.
10589.
10590. _____ is the most effective filter for separating luminance and chrominance
frequency components.
10591.
Low pass
10592.
Band pass
10593.
Notch

10594.

Comb

10595.
10596.
10597. The chrominance processing circuits can be deactivated when monochrome
broadcasts are received by the
10598.
Color killer
10599.
SAW filter
10600.
NOT gate
10601.
All of the above
10602.
10603.
10604. What is the standard video level, in percent PEV, for blanking?
10605.
25 %
10606.
0%
10607.
12.5 %
10608.
75 %
10609.
10610.
10611. What is the percent video level, in percent PEV, for black?
10612.
0%
10613.
25 %
10614.
12.5 %
10615.
70 %
10616.
10617.
10618. What is the standard video level, in percent PEV, for white?
10619.
0%
10620.
12.5 %
10621.
25 %
10622.
70 %
10623.
10624.
10625. One should first perform _____ before a convergence setup is performed.
10626.
Gray tracking
10627.
Screen setting
10628.
Alignment
10629.
Degaussing
10630.
10631.
10632. If there are too many harmonics, one should check the
10633.
Coupling
10634.
Tuning of circuits
10635.
Shielding
10636.
Any of these
10637.
10638.

10639. In transmitter amplifier design, an even-order harmonics can be prevented or
reduced by
10640.
Using a push-pull amplifier
10641.
Operating class C
10642.
Operating class AB
10643.
All of these
10644.
10645.
10646. The vertical and horizontal pulses are separated at the
10647.
Sync separator
10648.
AFC
10649.
High voltage
10650.
AGC
10651.
10652.
10653. The reason why buffer stage is included in a transmitter is to
10654.
Present a constant load to the oscillator stage
10655.
Present a low impedance to the oscillator stage
10656.
Stop the oscillator from generating parasitic oscillations
10657.
All of these
10658.
10659.
10660. Where is the operating position of a radio station?
10661.
On the bridge
10662.
At the control point
10663.
At the location of the receiver
10664.
At the location of the transmitter
10665.
10666.
10667. The alignment of the three color guns to a common point is known as
10668.
Blooming
10669.
Confetti
10670.
Demodulation
10671.
Convergence
10672.
10673.
10674. A _____ is equivalent to 525 scanning lines
10675.
Field
10676.
Frame
10677.
Cycle
10678.
Interface set
10679.
10680.
10681. A _____ represents one set of 262 ½ scanning lines
10682.
Field
10683.
Frame

10684.
10685.

Cycle
Interface set

10686.
10687.
10688. The number of scanning lines is _____ per second
10689.
14750
10690.
15570
10691.
15750
10692.
16550
10693.
10694.
10695. Picture frames are repeated at the rate of _____ per second
10696.
25
10697.
30
10698.
40
10699.
50
10700.
10701.
10702. Lack of raster is an indication of no
10703.
AGC
10704.
High voltage
10705.
Video signal
10706.
Television signal
10707.
10708.
10709. The sound and video signals are separated at the _____ of the TV receiver
10710.
IF stage
10711.
Video amplifier
10712.
Video detector
10713.
Burst separator
10714.
10715.
10716. The presence of color bars is an indication that there is a problem in the _____
circuit
10717.
Horizontal
10718.
Reactor
10719.
Burst separator
10720.
Chroma amplifier
10721.
10722.
10723. Type of emission produced when a frequency modulated transmitter is modulated
by a TV signal
10724.
A3F
10725.
F3F
10726.
A3C
10727.
F3C

10728.
10729.
10730. What is emission A3F?
10731.
RTTY
10732.
SSB
10733.
TV
10734.
Modulated CW
10735.
10736.
10737. What is emission F3F?
10738.
Facsimile
10739.
Modulated CW
10740.
Television
10741.
RTTY
10742.
10743.
10744. Cause of slow rising white “hum bars” is the television
10745.
Pad filter
10746.
Bad rectifier
10747.
Bad picture tube
10748.
High voltage transformer
10749.
10750.
10751. Adjusting the _____ may eliminate color confetti
10752.
Color chroma amplifier
10753.
Color killer
10754.
Color detector
10755.
Color oscillator
10756.
10757.
10758. Video signal amplitude determine the picture quality called
10759.
Chrominance
10760.
Brightness
10761.
Contrast
10762.
Luminance
10763.
10764.
10765. Part of broadcast day from midnight to local sunrise
10766.
Daytime
10767.
Experimental
10768.
Nighttime
10769.
Dawntime
10770.
10771.
10772. Part of broadcast day from local sunset to local sunrise
10773.
Dawntime

10774.
10775.
10776.

Nighttime
Daytime
Experimental

10777.
10778.
10779. What causes snow in television?
10780.
High Q in the tuned circuit
10781.
Excessive gain
10782.
Random noise in the signal
10783.
Insufficient wave traps
10784.
10785.
10786. Vestigial sideband is known as _____ type of emission
10787.
CF3
10788.
C3F
10789.
B8E
10790.
A3E
10791.
10792.
10793. Vestigial sideband modulation is commonly used in
10794.
TV broadcasting
10795.
Monaural broadcasting
10796.
Stereo broadcasting
10797.
HF point-to-point communications
10798.
10799.
10800. Which of the following filters block FM radio band for TV channels (2 to 13)?
10801.
High-pass filter
10802.
Low-pass filter
10803.
Band pass filter
10804.
Band-reject filter
10805.
10806.
10807. The FM broadcast band is from
10808.
535 to 1600 kHz
10809.
30 to 300 kHz
10810.
88 to 108 MHz
10811.
300 to 2000 MHz
10812.
10813.
10814. The type of emission used by standard AM radio broadcast
10815.
A5C
10816.
A0
10817.
A3
10818.
F3
10819.

10820.
10821. The standard AM radio broadcast belongs to which frequency band?
10822.
MF
10823.
HF
10824.
VHF
10825.
LF
10826.
10827.
10828. When were UHF channels (14 – 83) of television added?
10829.
1902
10830.
1945
10831.
1947
10832.
1952
10833. When was colored TV standards established in the United States?
10834.
1904
10835.
1945
10836.
1953
10837.
1960
10838.
10839.
10840. What synchronizes the horizontal line of the TV picture tube?
10841.
HFC
10842.
HSC
10843.
HAFC
10844.
All of these
10845.
10846.
10847. A measure of how well the receiver can respond to every weak signals/
10848.
Selectivity
10849.
Sensitivity
10850.
Fidelity
10851.
Quality factor
10852.
10853.
10854. What is the allowable frequency deviation of a commercial FM broadcast band?
10855.
15 kHz
10856.
75 kHz
10857.
5 kHz
10858.
100 kHz
10859.
10860.
10861. The final amplifier of either FM or AM transmitter is operated as
10862.
Class A
10863.
Class B
10864.
Class C
10865.
Class D

10866.
10867.
10868. Standard AM broadcasting use _____ for greater and efficient coverage
10869.
Circular polarized wave antenna
10870.
Horizontal polarized wave antenna
10871.
Both vertical and horizontal polarized wave antenna
10872.
Vertical polarized wave antenna
10873.
10874.
10875. Receiver sensitivity means
10876.
The frequency allocation of the system
10877.
Input impedance of the receiver
10878.
The ability of picking up weak signal
10879.
The power to deliver the information
10880.
10881.
10882. The main functions of the RF amplifier in a superheterodyne receiver is to
10883.
Provide improved tracking
10884.
Permit better adjacent-channel rejection
10885.
Improve the rejection of the image frequency
10886.
All of these
10887.
10888.
10889. Local oscillator of a broadcast receiver always tunes to a frequency higher than
the incoming frequency in order
10890.
To help the image frequency rejection
10891.
To allow easy tracking
10892.
To allow adequate frequency coverage without switching
10893.
All of these
10894.
10895.
10896. Type of filter used in TV receivers that separates the chroma signal from the
colorplexed video signal but leaves intact the Y-component
10897.
Comb filter
10898.
Bandpass filter
10899.
Color filter
10900.
Low pass filter
10901.
10902.
10903. What is the first letter-symbol for emission of unmodulated carrier?
10904.
A
10905.
N
10906.
H
10907.
F
10908.
10909.

10910. The channel for cable TV frequency range of 5.75 to 11.75 MHz
10911.
T-1
10912.
T-8
10913.
2
10914.
3
10915.
10916.
10917. The frequency range for cable TV channel T-13
10918.
23.75 – 29.75 MHz
10919.
60 – 66 MHz
10920.
41.75 – 47.55 MHz
10921.
5.75 – 11.75 MHz
10922.
10923. Channel 8 frequency range allocation in cable TV
10924.
54 – 60 MHz
10925.
66 – 72 MHz
10926.
180 – 186 MHz
10927.
204 – 210 MHz
10928.
10929.
10930. The _____ of a television system is a measure of its ability to delineate picture
detail
10931.
Contrast
10932.
Resolution
10933.
Hue
10934.
Pixels
10935.
10936.
10937. CCIR standards for the internal exchange of programmes on film for television
used
10938.
Rec 265-6
10939.
Rec 407-4
10940.
Rec 408-5
10941.
Rec 450-1
10942.
10943.
10944. CCIR transmission standards for FM sound broadcasting at VHF
10945.
Rec 601.2
10946.
Rec 501.2
10947.
Rec 500.4
10948.
Rec 450.1
10949.
10950.
10951. ISO Rec 23 in 1976 is the standard for
10952.
Recorded characteristics for magnetic sound records on full cost 16 mm
motion picture film

10953.
10954.
10955.

Projector usage of 16 mm motion picture films for direct front projector
Camera usage of 35 mm motion picture film
Camera usage of 16 mm motion picture film

10956.
10957.
10958. International broadcasting (short wave) uses frequency between _____
accordance with international agreements
10959.
7012 and 26100 kHz
10960.
6409 and 26100 kHz
10961.
5950 and 26100 kHz
10962.
10950 and 26100 kHz
10963.
10964.
10965. Which of the following station below is a regional channel?
10966.
Class I-A
10967.
Class II-D
10968.
Class III-B
10969.
Class IV
10970.
10971.
10972. The permissible power in kW of station II-A during nighttime is
10973.
0.25 – 50
10974.
10 – 50
10975.
1–5
10976.
None of these
10977.
10978.
10979. The television frequency which are now allocated to the land mobile services
10980.
806 and 192 MHz
10981.
800 and 806 MHz
10982.
668 and 674 MHz
10983.
776 and 782 MHz
10984.
10985.
10986. Numerical frequency band designation of channel 9
10987.
488 – 494 MHz
10988.
530 – 536 MHz
10989.
632 – 638 MHz
10990.
186 – 192 MHz
10991.
10992.
10993. Cable TV systems originate from
10994.
Germany
10995.
Dallas, Texas
10996.
Pennsylvania
10997.
Japan

10998.
10999.
11000. A term applied to third and higher order products, which can greatly degrade the
performance of a system
11001.
Composite triple beat
11002.
Single dual mode
11003.
Field strength
11004.
Noise
11005.
11006.
11007. A station similar to a translator station in terms of equipment and service area but
is permitted to originate originate programming from virtually any source
11008.
DME
11009.
LPTV
11010.
HDTV
11011.
ITFS
11012.
11013.
11014. Three stations are licensed to eligible educational entities for the distribution of
program material to students enrolled in instructional curricula
11015.
Translator
11016.
LPTV
11017.
HDTV
11018.
ITFS
11019.
11020.
11021. ITFS means
11022.
International Television Frequency Standard
11023.
Instructional Telephone Frequency Service
11024.
Instructional Television Fixed Service
11025.
International telecommunications Frequency Standard
11026.
11027.
11028. MDS means
11029.
Multipoint Distribution Service
11030.
Multipoint Digital Service
11031.
Maritime Data Standards
11032.
Multipoint Drop Standards
11033.
11034.
11035. Direct broadcast satellite based allocation
11036.
12.2 – 12.7 GHz downlink
11037.
17.3 – 17.8 GHz for uplink
11038.
3.7 – 4.2 GHz for downlink
11039.
12.2 – 12.7 GHz for downlink and 17.3 – 17.8 GHz for uplink
11040.

11041.
11042. What is the channel number of an FM station with 88.1 MHz carrier?
11043.
201
11044.
202
11045.
203
11046.
204
11047.
11048.
11049. What is the carrier frequency of an FM station with channel number of 300?
11050.
107.5 MHz
11051.
101.1 MHz
11052.
107.9 MHz
11053.
99.5 MHz
11054. If an FM station has an effective radiated power of 100 kW then it is under what
class?
11055.
Class A
11056.
Class B
11057.
Class C
11058.
Class D
11059.
11060.
11061. The video signal amplitude determines the quality of the picture otherwise known
as
11062.
Hue
11063.
Luminance
11064.
Chrominance
11065.
Contrast
11066.
11067.
11068. _____ is defined as to “send out in all direction”
11069.
Broadcast
11070.
Announce
11071.
Media
11072.
All of these
11073.
11074.
11075. The ultimate Dolby surround system is the
11076.
Dolby NR
11077.
Dolby Prologic
11078.
dBx
11079.
hall matrix

11080.
Microwave Communications
11081.
11082.
__________ is the progressive decrease of signal strength with increasing
distance.
11083.
Radiation
Attenuation
Modulation
Propagation
11084.
11085.
Calculate the effective earth’s radius if the surface refractivity is 301.
11086.
8493 km
8493 mmi
6370 km
6370 mi
11087.
11088.
If k-factor is greater than 1, the array beam is bent
11089.
Away from the earth
towards the ionosphere,
towards the earth
towards the outer space
11090.
11091.
the antenna separations (in meters) required for optimum operation of a space
diversity system can be calculated from:
11092.
S = 2λR/L
S = 3λR/L
S = λR/RL
S = λR/L
11093.
11094. where R = effective earth radius (m) and L = path length (m)
11095.
11096.
Rainfall is an important factor for fading of radio waves at frequencies above
11097.
10 GHz
100 GHz
1 GHz
100 MHz
11098.
11099.
Theoretically electromagnetic radiation field strength varies in inverse proportion
to the square of the distance, but when atmospheric attenuation effects and the absorption
of the terrain are taken into account the attenuation can be as high as the inverse _______
power of the distance.
11100.

Third
Fourth
Fifth
Sixth
11101.
11102.
11103.
What do you call an attenuation that occurs over many different wavelengths of
the carrier?
11104.
Rayleigh fading
Rician fading
Wavelength fading
Slow fading
11105.
11106.
Which of the reception problems below that is not due to multipath?
11107.
Delayed spreading
Rayleigh fading
Random Doppler shift
Slow fading
11108.
11109.
Which causes multipath or frequency-selective fading?
11110.
Small reflector
Nearer reflector
Further reflector
Large reflector
11111.
11112.
In microwave transmission using digital radio, what causes most intersymbol
interference?
11113.
Delayed spreading
Rayleigh fading
Random Doppler shift
Slow fading
11114.
11115.
A shipboard equipment which measures the distance between the ship’s bottom
and the ocean floor.
11116.
Fathometer
Echosounder
LORAN
SONAR
11117.
11118.
The cavity resonator
11119.

Is equivalent to an LC resonant circuit
In a reflect klystron has its output taken from the reflector plate
Produces a frequency which is independent of the cavity size.
Has a low Q factor for narrow operation.
11120.
11121.
At what position is the input signal inserted into a traveling-wave tube?
11122.
At the cathode end of the helix
At the collector
At the collector end of the helix
At the control grid of the electron gun
11123.
11124.
Coupling into and out of a traveling-wave tube can be accompanied by a
11125.
Waveguide match
Cavity match
Direct coax-helix match
All of the above
11126.
11127.
a high-power microwave pulse of the order of megawatts can be generated by a
11128.
traveling-wave tube
magnetron
reflex klystron
Gunn diode
11129.
11130.
A traveling-wave tube (TWT) amplifies by virtue of
11131.
The absorption of energy by the signal from an electron stream
The effect of an external magnetic field
The energy contained the cavity resonators
The energy liberated form the collector
11132.
11133.
What is the purpose of the electromagnetic field which surrounds a travelingwave tube?
11134.
To accelerate the electron
To velocity modulate the electron beam
To keep the electrons from spreading out
To slow down the signal on the helix
11135.
11136.
Which of the following is used as an oscillator device in the SHF band?
11137.
Thyratron tube
Tunnel diode
Klystron tube

Both B and C
11138.
11139.
Microwave frequencies are normally regarded as those in the range of
11140.
1 to 500 MHz
1000 to 10,000 GHz
1 to 100 GHz
10 to 1000 GHz
11141.
11142.
The highest frequency which a conventional vacuum-tube oscillator can generate
is not limited by the
11143.
Electron transit time
Distributed lead inductance
Inter-electrode capacitance
Degree of emission from the cathode
11144.
11145.
As the electron beam moves through a klystron’s intercavity drift space
11146.
Frequency modulation at the input cavity creates velocity modulation at the output cavity
Velocity modulation at the input cavity creates density modulation at the output cavity
Density modulation at the input cavity creates velocity modulation at the output cavity
Phase modulation at the input cavity creates velocity modulation at the output cavity.
11147.
11148.
The frequency of the oscillation generated by a magnetron, is mainly determined
by
11149.
The flux density of the external magnet
The ratio of the dc cathode voltage to the magnetic flux density
The number of the cavity resonators
The dimension of each cavity resonator
11150.
11151.
If the instantaneous RF potentials on the two sides of a magnetron cavity are of
opposite polarity, the operation is in the
11152.
π mode
π/2 mode
2π mode
π/4 mode
11153.
11154.
The Gunn diode oscillator
11155.
Is capable of generating continuous microwave power of the order of kilowatt
Generates frequencies which are below 100 MHz
Operates over a positive resistance characteristic
Depends on the formation of charge domain

11156.
11157.
What ferrite device can be used instead of duplexer of isolate microwave
transmitter and receiver when both are connected to the same antenna?
11158.
Isolator
Magnetron
Simplex
Circulator
11159.
11160.
To achieve good bearing resolution when using a pulsed-radar set, an important
requirement is
11161.
A narrow, antenna-beam width in the vertical plane
A narrow, antenna-beam width in the horizontal plane
A low repetition rate
A high duty cycle
11162.
11163.
When used in conjunction with a radar set, the purpose of an echo box is to
provide an artificial target.
11164.
Which may be used to tune the radar synchronizer
Which may be used to tune the radar receiver
To the tone of the pulse repetition
Tune the magnetron to the correct frequency
11165.
11166.
In a radar-set receiver, the usual mixer stage is
11167.
And FET
A tunnel diode
A silicon crystal
A Rochelle salts crystal
11168.
11169.
Klystron oscillators are most often used in the frequency range of
11170.
300 to 3000 MHz
3000 to 30000 MHz
30 to 30000 MHz
10 to 10000 MHz
11171.
11172.
Oscillators of a klystron tube are maintained
11173.
By bunches of electrons passing the cavity grids
By plate-to-cathode feedback
By feedback between the accelerating grid and the repeller
By circulating bunches of electrons within the cavities.
11174.

11175.
What allow microwave to pass in only one direction?
11176.
RF emitter
Capacitor
Varactor-triac
Ferrite emitter
11177.
11178.
In an SHF pulsed radar set, a reflex klystron can be used as a
11179.
Single mixer stage
Local oscillator
Transmitter oscillator
Duplexer stage
11180.
11181.
A Class-S Emergency Position-Indicating Radio Beacon (E.P.I.R.B)
11182.
Must be capable of floating or being secured to a survival
Must have its battery replaced after emergency use
May be tested during the first five minutes of any hour
All of these
11183.
11184.
A PPI cathode-ray tube as used on a radar set
11185.
Is used to check the percentage of modulation
Indicates both the range and azimuth of a target
Indicates only the range of a target
Is used for receiver alignment
11186.
11187.
The resonant frequency of a cavity resonator depends upon
11188.
The mode of operation
Its electrical dimensions
Its physical dimensions
The capacitor which tunes it
11189.
11190.
The maximum usable range of the usual radar set (on any particular range setting)
is determined by
11191.
The width of the transmitted pulses
The interval between transmitted pulses
The bandwidth of the receiver IF stages
The duty cycle
11192.
11193.
A reflex klystron is oscillating at the frequency of its resonant cavity. If the
reflector voltage is made slightly less negative, the
11194.

Oscillation will cease
Output power would increase
The frequency will decrease
Bunching would occur earlier in time
11195.
11196.
The coarse frequency adjustment of a reflex klystron is accomplished by
11197.
The AFC system
Adjusting the flexible wall of the resonant cavity
An adjustment in the synchronizer
Varying the repeller voltage
11198.
11199.
In a pulsed radar set, the STC circuit is used to
11200.
Improve the target bearing resolution
Increases receiver sensitivity for echoes from targets
Vary the pulse frequency in order to control the maximum target
Reduce interference from the effects of sea return
11201.
11202.
In a pulsed radar set, the function of the duplexer is to
11203.
Aid in calibrating the display unit
Prevent frequency drift in the klystron
Allow the transmitter and the receiver to operate from a common antenna
All of these
11204.
11205.
A magnetron is operated at a duty cycle of 0.001. It has a peak power output of
100 kilowatts. Its average power is
11206.
10,000 watts
100 watts
1,000 watts
1,000,000 watts
11207.
11208.
The aquadag coating on the inside of PPI tube is used
11209.
To focus the beam of primary electrons
To shield the electron beam from unidirectional magnetic
As a second anode and to prevent the build-up of secondary field
All of these
11210.
11211.
If the duration of the radar transmitted pulse, on a particular range of operation, is
increased, the required bandwidth of the receiver’s IF amplifiers
11212.
Must remain as before
Must be increased

May be decreased
Must be doubled
11213.
11214.
The main frequency determining element of a klystron is
11215.
The repeller voltage
The accelerating voltage
Its resonant cavity
Its mode of operation
11216.
11217.
A thin layer of dirt and grime coverts the reflecting surface of the parabolic dish
of a radar set. The particular effect on the performance of the radar will be
11218.
A decrease in range
A reduction in horizontal resolution
No noticeable effect
A decrease in gain
11219.
11220.
Which of the following permits a microwave signal to travel in one direction with
virtually no loss, but severely attenuates any signal attempting to travel in the reverse
direction?
11221.
Isolator
Wave trap
Tunnel diode
Circulator
11222.
11223.
It is possible to increase the maximum range of a radar equipment by
11224.
Lowering the pulse frequency
Raising the peak power of the transmitter
Narrowing the beam width and increasing the pulse duration
All of these
11225.
11226.
When it is desired that short-range targets be clearly seen on a pulsed-radar set, it
is important that the receiver and display system have
11227.
A long time constant
Low-pass filters
The shortest possible time
The restricted high-frequency response
11228.
11229.
Which of the following is used as a high power microwave oscillator?
11230.
Thyratron
Magnetron

Klystron
Reflex-klystron
11231.
11232.
Which of the following operating frequencies is used for the modern loran
navigational system?
11233.
Loran C: 100 kHz
Loran D: 10.2 kHz
Loran A: 1950 kHz
Loran B: 900 kHz
11234.
11235.
Which ferrite device can be used instead of a duplexer to isolate a microwave
transmitter and receiver when both are connected to the same antenna?
11236.
Isolator
Magnetron
Simplex
Circulator
11237.
11238.
The pulse frequency is equal to
11239.
Duty cycle/pulse width
The reciprocal of the pulse repetition rate
Pulse width x peak power/average power
All of these
11240.
11241.
In a radar set, a blocking oscillator can be used to
11242.
Act as the local oscillator converter stage
Provide the sweep voltage for the PPI tube
Produce a trigger pulse for the transmitter
As a single local oscillator converter stage
11243.
11244.
The intensity of the echoes (target definition) on a PPI display is determined by
the
11245.
Radio frequency
Pulse frequency and antenna rotation rate
Duty cycle
Average power
11246.
11247.
A duplexer circuit allows a transmitter and a receiver to operate from the same
antenna with virtually no interaction. This circuit may be replaced by a (an)
11248.
loss waveguide
circulator

isolator
gyrator
11249.
11250.
Which of the following frequencies are used by a class-C Emergency PositionIndicating Radio Beacon (E.P.I.R.B)?
11251.
156.65 MHz
121.5 MHz
156.76 MHz and 156.8 MHz
All of these
11252.
11253.
The repetition rate of a pulsed radar system indicates the
11254.
Frequency of the range-marker oscillator
Reciprocal of the duty cycle
Number of target echoes received on one second
Frequencies of the duty cycle
11255.
11256.
The radar set, sensitivity-time control circuit
11257.
Controls the width of the magnetron pulse
Is used to increase sea return
Can reduce sea-return response
Discriminates between targets that are very close together.
11258.
11259.
Which of the following is the ferrite device that buffers a microwave source from
the effects of a varying load, and thereby prevents the formation of standing waves?
11260.
Circulator
Duplexer
Isolator
Diplexer
11261.
11262.
Pulsed radar sets are primarily used to find the
11263.
Target’s range and bearing
Size and speed of a target
Speed and course of a target
Target’s range of speed
11264.
11265.
Which of the following factors is mainly concerned in the design of an antenna
system for pulsed radar set?
11266.
Duty cycle
Radio frequency
Pulse frequency

Pulse length
11267.
11268.
In a radar set receivers, an ac AFC system may be used to
11269.
Automatically maintain the correct magnetron frequency
Keep the IF stages on frequency
Maintain the desired klystron frequency
Provide automatic control of receiver gain
11270.
11271.
The input signal is introduced into the traveling-wave tube at the
11272.
Cathode
Anode
Cathode end of the helix
Collector end of the helix
11273.
11274.
The display on the PPI scope of a radar set will have greater intensity under the
following conditions
11275.
Higher antenna rotation speeds
Lower pulse repetition rate
Lower antenna rotation speeds
Both lower antenna rotation speeds and higher pulse repetition
11276.
11277.
The operating frequency of loran C lies within the
11278.
LF band
VLF band
MF band
HF band
11279.
11280.
The PPI tubes have an aquadag coating on the inside of the tube. The purpose of
this coating is
11281.
To act as the second anode
To shield the tube magnetically
To decelerate the electron beam
To deflect the electron beam
11282.
11283.
A traveling-wave tube Is used at frequencies in the order of
11284.
30 MHz
300 MHz
8000 MHz
100 MHz
11285.

11286.
The main benefit of using microwaves is
11287.
Lower-cost equipment
Simpler equipment
Greater transmission distances
More spectrum space for signals
11288.
11289.
Radio communication are regulated in the Philippines by the
11290.
DOTC
KBP
NTC
Department of Defense
11291.
11292.
Which of the following is not a disadvantage of microwaves?
11293.
Higher-cost equipment
Line-of-sight transmission
Conventional components are not usable
Circuits are more difficult to analyze
11294.
11295.
Which of the following is a microwave frequency?
11296.
1.7 MHz
750 MHz
0.98 GHz
22 GHz
11297.
11298.
Which of the following is not a common microwave application?
11299.
Radar
Mobile radio
Telephone
Satellite communications
11300.
11301.
Coaxial cable is not widely used for long microwave transmission lines because
of its
11302.
High loss
High cost
Large size
Excessive radiation
11303.
11304.
Stripline and microstrip transmission lines are usually made with
11305.
Coax

Parallel wires
Twisted pair
PCBs
11306.
11307.
The most common cross section of a waveguide is a
11308.
Square
Circle
Triangle
Rectangle
11309.
11310.
A rectangular waveguide has a width of 1 inch and a height of 0.6 in. Its cutoff
frequency is
11311.
2.54 GHz
3.0 GHz
5.9 GHz
11.8 GHz
11312.
11313.
A waveguide has a cutoff frequency of 17 GHz. Which of the following signals
will not be passed by the waveguide?
11314.
15 GHz
18 GHz
22 GHz
255 GHz
11315.
Signal propagation in a waveguide is by
11316.
Electrons
Holes
Electric and magnetic fields
Air pressure
11317.
11318.
When the electric field in a waveguide is perpendicular to the direction of wave
propagation, the mode is said to be
11319.
Vertical polarization
Horizontal polarization
Transverse electric
Transverse magnetic
11320.
11321.
The dominant mode in most rectangular waveguide is
11322.
TE 1.0
TE 1.2
TM 0.1

TM 1.1
11323.
11324.
A magnetic field is introduced into waveguide by a
11325.
Probe
Dipole
Stripline
Capacitor
11326.
11327.
A half-wavelength, close section of a waveguide that acts as a parallel resonant
circuit is known as a(n)
11328.
Half-wave section
Cavity resonator
LCR circuit
Directional coupler
11329.
11330.
Decreasing the volume of a cavity causes its resonant frequency to
11331.
Increase
Decrease
Remain the same
Drop to zero
11332.
11333.
__________ is a popular microwave mixer diode.
11334.
Gunn
Varactor
Hot carrier
IMPATT
11335.
11336.
Varactor and step-recovery diodes are widely used in what type of circuit?
11337.
Amplifier
Oscillator
Frequency multiplier
Mixer
11338.
11339.
Which diode is a popular microwave oscillator?
11340.
IMPATT
Gunn
Varactor
Schottky
11341.
11342.
Which type of diodes does not ordinarily operate with reverse bias?

11343.
Varactor
IMPATT
Snap-off
Tunnel
11344.
11345.
Low-power Gunn diodes are replacing
11346.
Reflex klystrons
TWTs
Magnetrons
Varactor diodes
11347.
11348.
Which of the following is not a microwave tube?
11349.
Traveling-wave tube
Cathode-ray tube
Klystron
Magnetron
11350.
11351.
In a klystron amplifier, velocity modulation of the electron beam is produced by
the
11352.
Collector
Catcher cavity
Cathode
Buncher cavity
11353.
11354.
A reflex klystron is used as a(n)
11355.
Amplifier
Oscillator
Mixer
Frequency multiplier
11356.
11357.
For proper operation, a magnetron must be accompanied by a
11358.
Cavity resonator
Strong electric field
Permanent magnet
High dc voltage
11359.
11360.
The operating frequency of klystrons and magnetrons is set by the
11361.
Cavity resonators
DC supply voltage

Input signal frequency
Number of cavities
11362.
11363.
A magnetron is used only as a/an
11364.
Amplifier
Oscillator
Mixer
Frequency multiplier
11365.
11366.
A common application for magnetron is in
11367.
Radar
Satellites
Two-way radio
TV sets
11368.
11369.
In a TWT, the electron beam is density-modulated by a
11370.
Permanent magnet
Modulation transformer
Helix
Cavity resonator
11371.
11372.
The main advantage of a TWT over a klystron for microwave amplification is
11373.
Lower cost
Smaller size
Higher power
Wider bandwidth
11374.
11375.
High-power TWTs are replacing what in microwave amplifiers?
11376.
MESFETs
Magnetrons
Klystrons
IMPATT diodes
11377.
11378.
The most widely used microwave antenna
11379.
Half-wave dipole
Parabolic
Hyperbolic
Horn
11380.
11381.
______________ is a measure of reliability expressed as the average number of

hours between successive failures.
11382.
MTBF
MTTR
Downtime
Outage time
11383.
11384.
The free space attenuation between two microwave antennas 40 km apart
operating at 8 GHz is
11385.
146.7 dB
142.55 dB
82.5 dB
86.7 dB
11386.
11387.
An active microwave radio repeater that can provide drops and inserts.
11388.
Broadband repeater
Baseband repeater
IF repeater
RF repeater
11389.
11390.
If the correction factor k equals 4/3 of the earth’s curvature, the microwave beam
would have a curvature that is ___________ than that of the earth.
11391.
More
Less
Equal
Not related
11392.
11393.
The optimum clearance from an obstacle in an microwave system is accepted as
__________ of the first fresnel zone radius.
11394.
0.6
0.5
0.9
1.5
11395.
11396.
The microwave beam curves the same than that of the earth when the value of the
correction factor k equals
11397.
0
4/3
2/3
Infinity
11398.

11399.
The time from the transmission of a radar pulse to its reception is 0.12 ms. The
distance to the target is how many nautical miles?
11400.
4.85 nmi
9.7 nmi
11.2 nmi
18.4 nmi
11401.
11402.
The ability of a radar to determine the bearing to a target depends upon the
11403.
Antenna directivity
Speed of light
Speed of the target
Frequency of the signal
11404.
11405.
The pulse duration of a radar signal is 699ns. The PRF is 185 pulses per second.
The duty cycle is
11406.
0.216 %
0.130 %
0.013 %
0.407 %
11407.
11408.
The Doppler effect allows which characteristics of a target to be measured?
11409.
Distance
Azimuth
Altitude
Speed
11410.
11411.
The Doppler effect is a change in what signal characteristics produced by relative
motion between the radar set and a target?
11412.
Amplitude
Phase
Frequency
Duty cycle
11413.
11414.
The most widely used radar transmitter component is a
11415.
Klystron
Magnetron
TWT
Power transistor
11416.
11417.
Low-power radar transmitters and receivers use which component?

11418.
GaAs FET
Magnetron
Gunn diode
Klystron
11419.
11420.
What component in a duplexer protects the receiver from the higher transmitter
output?
11421.
Waveguide
Bandpass filter
Notch filter
Spark gap
11422.
11423.
Most radar antennas use a
11424.
Dipole
Broadside array
Horn and parabolic reflector
Collinear array
11425.
11426.
The most common radar display is the
11427.
A scan
Color CRT
LCD
PPI
11428.
11429.
A radar antenna using multiple diploes or slot antennas in a matrix with variable
phase shifters is called a/an
11430.
A scan
Phased array
Broadside
Circulator polarized array
11431.
11432.
Which of the following is a typical radar operating frequency?
11433.
60 MHz
450 MHz
900 MHz
10 GHz
11434.
11435.
A microwave system requires the use of repeaters when
11436.
The intervening terrain is favorable

The distances involve are grater
The required reliability is meet
The radio fading is unacceptable
11437.
11438.
Are transmission lines which convey electromagnetic waves in highest
frequencies
11439.
Twister pair of telephone wires
Waveguides
Power lines
Coaxial cables
11440.
11441.
A microwave band of 10.9 to 36. GHz is considered as
11442.
C-band
X-band
Q-band
K-band
11443.
11444.
A microwave communications system space loss calculation formula.
11445.
94.2 + 20 log f + 20 log d
92.4 + 20 log f + 20 log d
94.2 + 10 log f + 20 log d
92.3 + 10 log f + 20 log d
11446.
11447.
A waveguide is also a
11448.
Low pass filter
High pass filter
Band pass filter
Band stop filter
11449.
11450.
A method of diversity reception where the signal is transmitted on two difference
frequencies over the same path
11451.
Space diversity
Frequency diversity
Polarization diversity
Wavelength diversity
11452.
11453.
A wire used to reduce the skin effect
11454.
AWG # 14
AWG # 15
Copper wire

Litz wire
11455.
11456.
Space diversity transmission means transmitting and receiving on two or more.
11457.
Different frequencies
Antennas operating on two different frequencies
Antennas operating on the same frequencies
Identical frequencies
11458.
11459.
The best system configuration to overcome multipath fading of microwave system
over the water
11460.
Space diversity
Frequency diversity
Polarization diversity
Wavelength diversity
11461.
11462.
When the value of k increases, the effective result is _______ of the equivalent
curvature
11463.
Flattening
Bulging
Sharp curvature
All of these
11464.
11465.
A traveling wave tube consists of
11466.
Electron gun, helix and repeller
Electron gun, helix and collector
Electron gun, repeller and collector
Buncher cavity and catcher cavity
11467.
11468.
Advantage of periscope antenna in microwave
11469.
Reduce tower height
Minimize interference to and from other neighboring stations
Shorten waveguide length
Easy to install
11470.
11471.
What is the cut-off frequency of a waveguide?
11472.
The highest frequency the waveguide operates
The lowest frequency the waveguide operates
The same as the operating frequency
The only frequency the waveguide operates.
11473.

11474.
When the clearance above the obstruction is equal to the radii of even fresnel
zones at the point of reflection. The RSL is
11475.
Increased
Decreased
Constant
Above threshold
11476.
11477.
What is the wavelength of a wave in a waveguide?
11478.
Greater than in free space
Depends only on the waveguide dimensions and the free-space wavelength
Inversely proportional to the phase velocity
Inversely proportional to the group velocity
11479.
11480.
The CCIR hypothetical reference circuit covering a distance of 25000 km consists
of a total of how many hops?
11481.
5
10
24
54
11482.
11483.
Water causes more attenuation particularly on what frequency?
11484.
20 GHz
63 GHz
183 GHz
202 GHz
11485.
11486.
At what frequency does oxygen cause excessive attenuation?
11487.
60 GHz
50 GHz
40 GHz
30 GHz
11488.
11489.
Which of the following is an atmospheric attenuation?
11490.
Attenuation due to water vapor and oxygen
Attenuation due to mist and fog
Attenuation due to other gases
Attenuation due to rain.
11491.
11492.
A microwave system operating at the 6 GHz band is carrying 600 voice channels.
What is the noise loading power in dBmO?

11493.
12.78
26.78
27.78
10.25
11494.
11495.
_________ is a microwave link between the down-town terminal and another out
of town terminal.
11496.
STL
Uplink
Downlink
Terrestrial
11497.
11498.
Attenuator is used in the traveling wave tube to
11499.
Prevent oscillation
Increase gain
Prevent saturation
All of these
11500.
11501.
Is a method of diversity reception applied to reflective path to reduce fading.
11502.
Frequency diversity
Space diversity
Polarization diversity
Wavelength diversity
11503.
11504.
What is the effective earth’s radius used in communications design?
11505.
4000 miles
K x 4000 miles
5000 miles
K x 5280 miles
11506.
11507.
IF bandwidth of a radar system is inversely proportional to
11508.
Pulse width
Pulse interval
Peak transmit power
All of these
11509.
11510.
EADI stands for
11511.
Electronic Air Data Indicator
Electronic Altitude and Distance Indicator

Electronic Altitude and Director Indicator
Electronic Air and Distance Indicator
11512.
11513.
Which aircraft navigational system determines the time to station (TTS) or time to
go (TTG)?
11514.
ADF
DME
Timer
ATC
11515.
11516.
What frequency does a radio altimeter operate?
11517.
33500 kHz
43000 kHz
33500 MHz
43500 MHz
11518.
11519.
What inflight system allows passengers to make telephone calls, send faxes, and
computer data shop and play computer games, etc.?
11520.
Inflight Satellite System
Terrestrial Flight Telephone System
World Airline Entertainment System
Satellite Phone
11521.
11522.
ADF stands for
11523.
Audio Direction Findings
Automatic Direction Finder
Alternate Direction Finder
Automatic Distance Finder
11524.
11525.
RF carrier of the middle marker is modulated at ____ Hz.
11526.
1300
1400
1500
1600
11527.
11528.
Which of the following is considered as the major advantage of using a helix
traveling wave tube?
11529.
Cheaper
Less noise
High power

Wide bandwidth
11530.
11531.
RADAR stands for
11532.
Radio Distance and Ranging
Radio Detection and Ranging
Radio Direction and Ranging
Radio Distance and Range
11533.
11534.
11535.
11536.
11537.
11538.
11539.
11540.
11541.
11542.
11543.
11544.
11545.
11546.
11547.
11548.
11549.
11550.
11551.
11552.
11553.
11554.
11555.
11556.
11557.
Acoustics
11558.
An instrument designed to measure a frequency-weighted value of the sound
pressure level.
11559. Sound-level meter
11560. Transducer
11561. Sound pressure meter
11562. Sound analyzer
11563.
A unit of noisiness related to the perceived noise level
11564. Noy
11565. Sone
11566. dB

11567. phone
11568.
An agreed set of empirical curves relating octave-band osund pressure level to the
center frequency of the octave bands
11569. C-message weighting curves
11570. Psophometric weighting curves
11571. Noise rating curves
11572. F1A weighting curves
11573.
The frequency of free vibration
11574. Resonant frequency
11575. Natural frequency
11576. Center frequency
11577. Normal frequency
11578.
The transmission of sound from one room to an adjacent room, via common
walls, floors or ceilings.
11579. Flanking transmission
11580. Refraction
11581. Reflection
11582. Reverberation
11583.
A measure of threshold hearing, expressed in decibels relative to a specifoed
standard of normal hearing.
11584. Hearing loss
11585. Sensation level
11586. Hearing level
11587. Sound pressure level
11588.
A certain machine with a slightly out-of-balance motor rotating at 1800/min is
fixed on a perfectly elastic mount with a static compression of 2.50 mm. Calculate the
resonant frequency of mount.
11589. 10 Hz
11590. 20 Hz
11591. 30 Hz
11592. 40 Hz
11593.

11594.
Calculate the lowest resonant frequency for a brick partition 120 mm thick, 4m by
2min area with longitudinal wave velocity of 2350 m/s. (Assume that it is supported at its
edges.)
11595. 10 Hz
11596. 20 Hz
11597. 30 Hz
11598. 40 Hz
11599.
Velocity of sound in air.
11600. 300 m/s
11601. 330 m/s
11602. 1130 m/s
11603. 344 m/s
11604.
What is the expected critical frequency for a 120 mm thick brick wall? Assume a
longitudinal wave velocity in brick of 2350 m/s and that the velocity of sound in air is
330 m/s.
11605. 114.5 Hz
11606. 214.5 Hz
11607. 314.5 Hz
11608. 414.5 Hz
11609.
The sound power level of a certain jet plane flying at a height of 1km is 160 dB
(re10-12W). Find the maximum sound pressure level on the ground directly below the
flight path assuming that the aircraft radiates sound equally in all directions.
11610. 59.1 dB
11611. 69.1 dB
11612. 79.1 dB
11613. 89.1 dB
11614.
Speaker is a device that
11615. Converts sound waves into current and voltage
11616. Converts current variations into sound waves
11617. Converts elctrical energy to mechanical energy
11618. Converts elctrical energy to electromagnetic energy
11619.
Which type of microphone operates on the principle that the electrical resistance
of carbon granules varies as the pressure on the granules vary?
11620. Dynamic
11621. Crystal
11622. Carbon
11623. Ribbon-type
11624.
Bass response is
11625. Maximum highfrequency response
11626. Emphasizing the high audio frequency
11627. Bypassing high audio frequencies
11628. Bypassing low audio frequencies
11629.
Pure tone of sound used as standard on testing
11630. 1 Hz
11631. 10 Hz
11632. 100 Hz

11633. 1000 Hz
11634.
___________ is early reflection of sound.
11635. Echo
11636. Reverberation
11637. Pure sound
11638. Intelligible sound
11639.
Noise reduction system used for film sound in movie.
11640. Dolby
11641. dBa
11642. dBx
11643. dBk
11644.
What is the sound energy per unit area at right angles to the propagation direction
per unit time?
11645. Loudness
11646. Coherence
11647. Sound pressure
11648. Sound intensity
11649.
________ is the unit of loudness level of a sound.
11650. Sone
11651. Decibel
11652. Mel
11653. Phon
11654.
____________ is the average rate of transmission of sound energy in a given
direction through a cross-section area of 1 sqm at right angles to the direction.
11655. Sound pressure
11656. Loudness
11657. Sound intensity
11658. Pressure variation
11659.
What is the unit of pitch?
11660. Sone
11661. Phon
11662. Decibel
11663. Mel
11664.
A measure of the intensity of sound in comparison to another sound intensity.
11665. Phon
11666. Decibel
11667. Pascal
11668. Watts
11669.
Sound wave has two main characteristics which are
11670. Highness and loudness
11671. Tone and loudness
11672. Pitch and loudness
11673. Rarefraction and compression
11674.
Which type of microphone operated by electromagnetic induction that generates
an output signal voltage?
11675. Carbon

11676. Dynamic
11677. Crystal
11678. Condenser
11679.
The exciter lamp in the optical sound part of a film projector draws 5 A at 10 V.
How much power in watts is this light consuming?
11680. 10 watts
11681. 20 watts
11682. 40 watts
11683. 50 watts
11684.
Assume the speed of sound is 1,130 ft/s. What frequency has a wavelength of 1
foot, 1.5 inches?
11685. 500 Hz
11686. 1000 Hz
11687. 1500 Hz
11688. 2000 Hz
11689.
The wire must bring 100 average watts to a 4 ohms loudspeaker must safely carry
what rms current?
11690. 2 A
11691. 4 A
11692. 5 A
11693. 6 A
11694.
A church has an internalvolume of 90.05 ft3 (2550 m3). When it contains
customary sabine sof absorption (186 metric sabines), what will be its reverberation time
in seconds.
11695. 2.0
11696. 2.2
11697. 2.5
11698. 3.0
11699.
If the RMs sound pressure is 5lb/ft2, what is the sound presure level?
11700. 7.6 dB
11701. 108 dB
11702. 88 dB
11703. 10 dB
11704.
Speed that is faster than speed of sound.
11705. Ultrasonic
11706. Supersonic
11707. Subsonic
11708. Transonic
11709.
Sound waves travel faster in water at a ______ speed.
11710. 12.4 miles/sec
11711. 5000 ft/sec
11712. 186,000 ft/sec
11713. 3141 ft/sec
11714.
What is the sound power from a motor car whose SPL at a distance of 7.5 m is 87
dB assuming that it radiates sound unifomly?
11715. 0.15 W

11716. 0.21 W
11717. 0.24 W
11718. 0.18 W
11719.
Crest-to-crest distance along the direction to wave travel.
11720. Compression
11721. Wavelength
11722. Period
11723. Sound wave
11724.
Sound intensity level is _________.
11725. 10 log I/Iref
11726. 10 log P/Pref
11727. 20 log I/Iref
11728. 30 log P/Pref
11729.
Sound pressure level is _________.
11730. 20 log P/ Pref
11731. 30 log P/ Pref
11732. 10 log P/ Pref
11733. 20 log I/Iref
11734.
The most important specification of loudspeakers and microphones.
11735. Frequency response
11736. Field strength
11737. Power density
11738. Gain
11739.
Lowest fequency produced by a musical instrument.
11740. Midrange
11741. Harmonic
11742. Reflection
11743. Refraction
11744.
Tendency of a sound energy to spread.
11745. Diffraction
11746. Rarefraction
11747. Reflection
11748. Refraction
11749.
Whenwaves bend away from straight lines of travel, it is called _________.
11750. Reflection
11751. Diffraction
11752. Rarefraction
11753. Refraction
11754.
Required time for any sound to decay to 60 dB.
11755. Echo time
11756. Delay time
11757. Reverberation time
11758. Transient time
11759.
The intensity needed to produce an audible sound varies with __________.
11760. Frequency
11761. Noise

11762. Amplitude
11763. Tone
11764.
Sound that vibrates too high for the human ear to hear (over 20 kHz).
11765. Subsonic
11766. Transonic
11767. Ultrasonic
11768. Stereo
11769.
Which microphone will be damaged if exposed to high temperature above 52°C?
11770. Dynamic
11771. Crystal
11772. Ribbon
11773. Capacitor
11774.
A thin springy sheet of bakelite or metal that permits the voice coil in a dynamic
loudspeaker to move back and forth salong the core of its magnet.
11775. Vibrator
11776. Diaphragm
11777. Hypex
11778. Spider
11779.
One hundred twenty µbars of pressure variation is equal to
11780. 120 dB SPL
11781. 57.78 dB SPL
11782. 115.56 dB SPL
11783. 41.58 dB SPL
11784.
The reverberation time of a 184.2 cubic meters broadcast studio is 0.84 sec. Find
the absorption effect of the materials used in metric sabines.
11785. 35.3
11786. 10.96
11787. 379.8
11788. 109.6
11789.
What is the microphone characteristic that results in a boost in bassfrequencies for
close microphone spacing?
11790. Field effect
11791. P.A. effect
11792. Proximity effect
11793. Reverberation
11794.
What is the audio frequency range?
11795. 20 kHz to 20 MHz
11796. 0 Hz to 20 kHz
11797. 300 Hz to 400 Hz
11798. 20 Hz to 20 kHz
11799.
What is the bass frequency range?
11800. 2500 Hz to 5000 Hz
11801. 5000 Hz to 10 kHz
11802. 40 kHz to 160 kHz
11803. 10 Hz to 20 kHz
11804.
High frequency range of audio signals.

11805. 2500 Hz to 5000 Hz
11806. 5000 Hz to 10 kHz
11807. 10 kHz to 20 kHz
11808. 20000 Hz to 30 kHz
11809.
What is the dB SPL of a voice paging in an office?
11810. 90
11811. 65
11812. 55-60
11813. 80-85
11814.
What is the dB SPL of an auditorium with contemporary music?
11815. 80-95
11816. 85-90
11817. 95-100
11818. 100-105
11819.
What is the church dB SPL with speech reinforcement only?
11820. 90
11821. 80-85
11822. 85-90
11823. 90-95
11824.
Intensity can also be called as
11825. Volume
11826. Loudness
11827. Sharpness
11828. Strength
11829.
Tje loudness of a sound depends upon the energy of motion imparted to ________
molecules of the medium transmitting the sound.
11830. Transmitting
11831. Running
11832. Moving
11833. Vibrating
11834.
_________ is affected by the distance between the listener and the source of the
sound and its intensityvaries inversely with the square of its distance.
11835. Volume
11836. Bass
11837. Treble
11838. Loudness
11839.
If the distance between the listener and the source of the sound is doubled, the
intensity is reduced to
11840. ½
11841. 1/3
11842. 2/3
11843. 1/4
11844.
If the distance between the listener and the source of the sound is decreased to ½
tye original amount, the intensity of the sound would be
11845. 2 times as great
11846. 3 times as great

11847. 4 times as great
11848. 5 times as great
11849.
At a sensation level of 40 dB, 1000 Hz tone is
11850. 1000 mels
11851. 500 mels
11852. 2000 mels
11853. 100 mels
11854.
If the sound waves are converted to electrical waves by a microphone, what is the
frequency of the electric current?
11855. 3 - 30 MHz
11856. 25 – 8000 Hz
11857. 4 – 40 Hz
11858. 30 – 3000 Hz
11859.
For a music lover concert “A” is 440 Hz. If a musical note one octave higher were
played, it would be _______ that frequency.
11860. One – half
11861. One-fourth
11862. Double
11863. Triple
11864.
In a 220 Hz, if a note was played one octave lower, it would be ______.
11865. 22 Hz
11866. 27.5 Hz
11867. 440 Hz
11868. 110 Hz
11869.
Much of music is generally reffered to in
11870. Harmonics
11871. Good hearing
11872. Fidelity
11873. Octaves
11874.
_________ is an undesired change in wave form as the signal passes through a
device.
11875. Noise
11876. Vibration
11877. Distortion
11878. Harmonics
11879.
Distortion enhances intelligibly when an ________ is added.
11880. Equalizer
11881. Igniter
11882. Exciter
11883. Emulsifier
11884.
A class of signal processors.
11885. Amplifiers
11886. Equalizers
11887. Microprocessors
11888. Exciters
11889.
Half construction and internal finishes affect the final sound quality ________.

11890. poorly
11891. mildly
11892. significantly
11893. badly
11894.
Positioning a loudspeaker near a wall can dramatically alter its frequency
response in two distinct ways namely;
11895. Gump and dump
11896. Hump and notch
11897. Fade and gone
11898. Bad and worst
11899.
The acoustics of most auditoria are very ________ when the room is full
compared to the empty condition.
11900. Different
11901. Similar
11902. Good
11903. Bad
11904.
A _________ converts acoustical energy.
11905. Electro-acoustic
11906. Microphone transducer
11907. Microphone
11908. Electric Microphone
11909.
All microphone have two basic components namely, ___________.
11910. Wired and body
11911. Ceramic and crystal
11912. Diaphragm and generating element
11913. Coil and magnet
11914.
The kinds of generating elements are __________.
11915. Expense and fidelity
11916. Complexity and ruggedness
11917. Longevity
11918. All of these
11919.
When the average absorption is greater than 0.2, __________ formula is used to
compute the actual reverberation time.
11920. Sabine
11921. Stephen and Bate
11922. Norris-Eyring
11923. Notch
11924.
At room temperature, what is the velocity of sound in meters/seconds?
11925. 348.03 cm/s
11926. 980 cm/s
11927. 980 m/s
11928. 341.8 m/s
11929.
Calculate the velocity of sound in ft./sec. if the temperature is 1490C?
11930. 1530.03 ft/sec
11931. 1320 ft/sec
11932. 1357.03 ft/sec

11933. 1920.345 ft/sec
11934.
The wavelength of a sound of 20 kHz frequency is
11935. 16.5 m
11936. 16.5 cm
11937. 16.5 mm
11938. 16.5 um
11939.
The radio of frequencies is termed
11940. Octave
11941. Interval
11942. Harmonics
11943. Masking
11944.
What is the increase in sound pressure level in dB, if the pressure is doubled?
11945. 2 dB
11946. 3 dB
11947. 6 dB
11948. 4 dB
11949.
A term which is subjected but dependent mainly on frequency and also affected
by intensity,
11950. Timbre
11951. Quality
11952. Frequency
11953. Pitch
11954.
An effect that occurs in the ear where a louder sound can reduce or even stop the
nerve voltage generated by a weaker sound.
11955. Piezoelectric effect
11956. Skin effect
11957. Lasing
11958. Masking
11959.
For computation of ideal reverberation time, which formula is applicable?
11960. Sabine
11961. Stephen and Bate
11962. Norris-Eyring
11963. Notch
11964.
The __________ of the sound is a subjective effect which is a function of the ear
and brain.
11965. Pitch
11966. Frequency
11967. Timbre
11968. Loudness
11969.
Define as the time taken from the intensity of sound energy in the room to drop to
one millionth of its initial value.
11970. Reverberation time
11971. Transit time
11972. Decaying time
11973. Response time
11974.
__________ is the sound energy per unit area at right angles of the propagation

direction, per unit time.
11975. Loudness
11976. Coherence
11977. Sound stress
11978. Sound intensity
11979.
One octave above 600 Hz is
11980. 601 Hz
11981. 800 Hz
11982. 1400 Hz
11983. 1200 Hz
11984.
A car horn outdoors produces a sound intensity level of 90 dB at 10 m away. At
this distance, what is the sound power in watt?
11985. 0.63
11986. 1.26
11987. 0.315
11988. 0.56 x 10-6
11989.
The unit of loudness level
11990. Sone
11991. dB
11992. Mel
11993. Phon
11994.
Consist of a rapid succession of noticeable echoes.
11995. Rarefaction
11996. Refraction
11997. Reflection
11998. Flutter echo
11999.
Laid the foundations of acoustic theory of buildings.
12000. Charles H. Townes
12001. W.C Sabine
12002. A. Javin
12003. Stephen and Bate
12004.
An aural sensation by pressure variations in the air which are always produced by
some source of vibrations.
12005. Music
12006. Sound
12007. Disturbance
12008. Speech
12009.
Considered to be the threshold of hearing.
12010. 10-12 W/cm2
12011. 10-16 W/m2
12012. 10-13 W/m2
12013. 10-12 W/m2
12014.
The average absorption for a person is
12015. 5.7 units
12016. 4.7 units
12017. 6.7 units

12018. 3.7 units
12019.
The number of vibration or pressure fluctuations per seconds.
12020. Frequency
12021. Timbre
12022. Quality
12023. Pitch
12024.
Defined as the average rate of transmission of sound energy in a given direction
through a cross-sectional area of 1 m2 at right angles to the direction.
12025. Sound pressure
12026. Loudness
12027. Sound intensity
12028. Pressure variation
12029.
What is the sound pressure level (SPL) of a sound having a RMS pressure of 200
N/m2?
12030. 150 dB
12031. 140 dB
12032. 170 dB
12033. 160 dB
12034.
The minimum sound intensity that can be heard is termed
12035. Threshold of feeling
12036. Threshold of pain
12037. Threshold of sensation
12038. Threshold of hearing
12039.
What is the intensity of the sound whose RMS pressure is 200 N/m2?
12040. 96.9 W/m2
12041. 97.9 W/m2
12042. 95.9 W/m2
12043. 94.9 W/m2
12044.
The unit of pitch.
sone
pitch
dB
Mel
12045.
What is the increase in sound pressure level in dB, if the intensity is doubled?
2 dB
3 dB
4 dB
6 dB
12046.
The velocity of sound is considered to be constant at ________ for the purpose of
acoustics.
300 m/s
330 mm/s
330 µm/s
330 cm/s
12047.
12048.

12049.
12050.
12051.
12052.
12053.
12054.
12055.
12056.
12057.
12058.
12059.
12060.
12061.
12062.
12063.
12064.
12065.
12066.
12067.
12068.
12069.
12070.
12071.
12072.

Radiation and wave propagation
________ is the amount of voltage induced in wave by an electro magnetic wave.
receive voltage
magnetic induction
field strength
power density
12073.
An electro magnetic wave consists of ___________.
both electric and magnetic fields.
an electric field only
a magnetic field only
non-magnetic field only
12074.
What is the lowest layer of the ionosphere?
F1
F2
E
D
12075.
Who profounded electro magnetic radiation theory?
Sir Edward Appleton
James Clerk Maxwell
Christian Huygens
Sir Isaac Newton
12076.
The D, E and F layers are known as ____________.
Mark – space Layers
Davinson- Miller Layers

Kennely – Heaviside Layers
Appleton Layers
12077.
Different grouping of the electromagnetic spectrum.
band
bandwidth
channel
group
12078.
What is the relation in degrees of the electric and magnetic fields in an
electromagnetic wave?
180 degrees
90 degrees
270 degrees
45 degrees
12079.
A changing electric field gives rise to ________.
a magnetic field
sound field
electromagnetic waves
near and far fields
12080.
Frequencies in the UHF range propagate by means of
ground waves
sky waves
surface waves
space waves
12081.
In electromagnetic waves, polarization __________.
is caused by reflection
is due to the transverse nature of the waves
results from the longitudinal nature of the waves
is always vertical in an isotropic medium
12082.
Electromagnetic Waves are refracted when they ___________.
pass into a medium of different dielectric constants
are polarized at right angles to the direction of propagation
encounter a perfectly conducting surface
pass through a small slot in a conducting plane
12083.
What is the highest layer of the atmosphere?
ionosphere
stratosphere
troposphere
ozone layer
12084.
What is the thickest layer of the ionosphere?
F2
F1
D
E
12085.
Effective Earth radius to true earth radius ratio.
index of refraction
K factor

Fresnel zone
path profile
12086.
Fading due to interference between direct and reflected rays.
atmospheric-mutipath
Fresnel zone
reflection-multi path
Rayleigh fading
12087.
The layer that reflects very low frequency waves and absorbs medium frequency
waves.
D Layer
E Layer
F1 Layer
F2 Layer
12088.
What layer is used for high-frequency day time propagation?
D Layer
E Layer
F1 Layer
F2 Layer
12089.
What is the highest frequency that can be sent straight upward and be returned to
earth?
MUF
skip frequency
critical frequency
gyro frequency
12090.
High frequency range is from?
0.3 to 3MHz
3 to 30MHz
30 to 300MHz
3to 30MHz
12091.
Medium frequency range is from
0.01 to 0.03 MHz
0.03 to 0.3MHz
0.3 to 3MHz
3 to 30 MHz
12092.
In tropospheric scatter propagation, the attenuation is dependent on
scatter angle
take-off angle
antenna size
the troposphere
12093.
If the transmitter power remains constant, an increase in the frequency of the sky
wave will
lengthen the skip distance
increase the range of the ground wave
reduce the length of the skip distance
have no effect on the ground wave range
12094.
What is the unit of electric field strength?

volts per square meter
volt per square cm
volts per meter
milivolt per watt
12095.
Velocity of a radio wave in free space.
186,000 miles per sec
300x106 meters per sec
162,000 nautical mile per sec
all of the above
12096.
Refers to the direction of the electric field vector in space.
polarization
directivity
radiation
ERP
12097.
An TEM wave whose polarization rotates.
vertically polarized
omnidirectional
horizontally polarized
circularly polarized
12098.
velocity of light in free space
300x106m/s
300x106km/s
186,000km/s
186,000m/s
12099.
What is the effective radiated power of a repeater with 200W transmitter power
output, 4dB feed line loss, 4dB duplxer and circulator loss, and 10dB feed line antenna
gain?
2000W
12100.
b. 126W
12101.
c. 317W
12102.
d. 260W
12103.
Radio wave that is far from its sources is called
Plane wave
isotrpic wave
vertical wave
horizontal wave
12104.
Light goes from medium A to medium B at angle of incidence of 40 degrees. The
angle of refraction is 30 degrees. The speed of light in B
is the same as that in A
is greater than that in A
maybe any of these, depending on the specific medium
is less than that in A
12105.
In a vacuum, the speed of an electromagnetic wave
depends on its constant
depends on its wavelength
depends on its electric and magnetic fields

is a universal constant
12106.
The depth of an object submerged in a transparent liquid
always seems more that its actual depth
12107.
b may seem less or more than its actual depth, depending on the object
12108.
c. always seems less than its actual depth
12109.
d. may seem less or more than its actual depth, depending on the
transparent liquid
12110.
What is a wave front?
a voltage pulse in a conductor
a current in a conductor
a fixed point in an electromagnetic wave
a voltage pulse across a resistor
12111.
VHF ship station transmitters must have the capability of reducing carrier power
to
1W
10W
25W
50W
12112.
Most of the effects an electro magnetic wave produces when it interacts with
matter are due to its
magnetic field
speed
frequency
electric field
12113.
A mobile receiver experiences “dead” areas of reception as a result of
atmospheric absorption
tropospheric scatter
sporadic E
shading of the RF signal by hills and trees
12114.
When the electric field is perpendicular in the surface of the earth, what is the
polarization of the TEM wave?
elliptical
vertical
horizontal
circular
12115.
When the magnetic field is perpendicular to the surface of the earth, what is the
polarization of the TEM wave?
circular
horizontal
vertical
elliptical
12116.
When the magnetic field is parallel to the surface of the earth, what is the
polarization of the TEM wave?
elliptical
horizontal
vertical

circular
12117.
What are the two interrelated fields considered to make up an electromagnetic
wave
an electric field and a current field
an electric field and voltage field
an electric field and a magnetic field
a voltage and current fields
12118.
How does the bandwidth of the transmitted signal affect selective fading?
it is more pronounced at narrow bandwidths
it is equally pronounced at both narrow and wide bandwidths
it is more pronounced at wide bandwidths
the receiver bandwidth determines the selective fading
12119.
A wide-bandwidth communications systems in which the RF carrier varies
according to some predetermined sequence.
amplitude compandored single sideband
SITOR
spread spectrum communication
time-domain frequency modulation
12120.
A changing magnetic field gives rise to
sound field
magnetic field
electric field
nothing in particular
12121.
When a space-wave signal passes over a mountain ridge, a small part of the
signal is diffracted down the far side of the mountain. This phenomenon is called
discontinuity scattering
troposheric ducting
knife-edge diffraction
space-wave refraction
12122.
The index of refraction of a material medium
is greater than 1
is less than 1
is equal to 1
maybe any of the bove
12123.
At what speed do electromagnetic waves travel in free space?
approximately 468 million meters per second
approximately 186300 ft/s
approximately 300 million m/s
approximately 300 million miles/s
12124.
What is the effective earth radius when surface refractivity, and N equals 300?
6370km
12125.
b.7270km
12126.
c.7950km
12127.
d. 8500km
12128.
If N = 250, what is the earth radius K-factor?
1.23

1.29
1.33
1.32
12129.
Electric field that lies in a plane perpendicular to the earths surface
vertical polarization
horizontal polarization
circular polarization
elliptical polarization
12130.
Electric field that lies in a plane parallel to the earth’s surface
vertical polarization
horizontal polarization
circular polarization
elliptical polarization
12131.
Indicate which one of the following terms applies to trposcatter propagation
SIDs
fading
atmospheric storms
faraday rotation
12132.
VLF waves are used for some types of services because
of the low power required
12133.
b the transmitting antennas are of convenient size
12134.
c. they are very reliable
12135.
d. they penetrate the ionosphere easily
12136.
Indicate which of the following frequencies cannot be used for reliable beyondthe-horizon terrestrial communications without repeaters
20KHz
15MHz
900MHz
12GHz
12137.
High-frequency waves are
absorbed by the F2 layer
reflected by the D leayer
capable of use for long-distance communications on the moon
affected nby the solar cycle
12138.
Distances near the skip distance should be used for sky-wave propagation
to avaoid tilting
to prevent sky-wave and upper ray interference
to avoid the faraday effect
so as not to exceed the critical frequency
12139.
A ship-to-ship communications system is plague by fading. The best solution
seems to be the use of
a more directional antenna
a broadband antenna
frequency diversity
space diversity
12140.
A range of microwave frequencies more easily passed by the atmosphere than are

the others is called a
window
critical frequency
gyro frequency range
resonance in the atmosphere
12141.
frequencies in the UHF range normally propagate by means of
ground waves.
sky waves
surface waves
space waves
12142.
Tropospheric scatter is used with frequencies in the following range
HF
VHF
UHF
VLF
12143.
The ground wave eventually disappears as one moves away from the transmitter
because of
interference from the sky wave
loss of line – of – sight conditions
maximum single-hop distance limitation
tilting
12144.
in electromagnetic waves, polarization means
the physical orientation of magnetic field in space
the physical orientation of electric field in space
ionization
the presence of positive and negative ions
12145.
an electromagnetic waves travel in free space, only one of the following can
happen to them.
absorption
attenuation
refraction
reflection
12146.
the absorption of a radio waves by the atmosphere depends on
their frequency
their distance from the transmitter
the polarization of the waves
the polarization of the atmosphere
12147.
diffraction of electromagnetic waves
is caused by reflections from the ground
arises only with spherical wavefronts
will occur when the waves pass through a large slot
may occur around the edge of a sharp object
12148.
12149.
In an electromagnetic wave the electric field is
12150. Parallel to both magnetic field and the wave direction
12151. Perpendicular to both the magnetic field and the wave direction

12152. Parallel to the magnetic field and perpendicular to the wave direction
12153. Perpendicular to the magnetic field and parallel to the wave direction
12154.
The highest frequencies are found in
12155. X-rays
12156. Radio waves
12157. Ultraviolet rays
12158. Radar waves
12159.
Electromagnetic waves transport
12160. Wavelength
12161. Charge
12162. Frequency
12163. Energy
12164.
The ionosphere is a region of ionized gas in the upper atmosphere. The
ionosphere is responsible for
The blue color of the sky
Rainbows
Long distance radio communication
The ability of satellites to orbit the earth
12165.
Light of which the following colors has the shortest wavelength
Red
Yellow
Blue
Green
12166.
The quality in sound that corresponds to color in light is
Amplitude
Resonance
Waveform
Pitch
12167.
All real images
Are erect
Can appear on screen
Are inverted
Cannot appear on a screen
12168.
When a beam of light enters one medium from another, a quality that never
changes is its
Direction
Frequency
Speed
Wavelength
12169.
Relative to the angle of incidence, the angle of refraction
Is smaller
Is larger
Is the same
Either A or B above
12170.
A light ray enters one medium from another along the normal. The angle of
refraction is

0
90 degrees
Equal to the critical angle
Dependent on the indexes of refraction of the two media
12171.
What layer aids MF surface-wave propagation a little and reflects some HF waves
in daytime?
E layer
D layer
F1 layer
F2 layer
12172.
Dispersion is the term used to describe
The splitting of white light into its component colors in regraction
The propagation of light in straight lines
The bending of a beam of light when it goes from one medium to another
The bending of a beam of light when it strikes a mirror
12173.
The depth of an objects submerged in a transparent liquid
Always seems less than its actual depth
Always seems more than its actual depth
May seems more than its actual depth, depending on the index of refraction of the
liquid
May seem less or more than its actual depth depending on the angle of view
12174.
Total internal reflection can occur when light passes from one medium to another
That has a lower index of refraction
That has a larger index of refraction
That has the same index of refraction
At less than the critical angle
12175.
When the light ray approaches a glass-air interface from the glass side at the
critical angle, the angle of refraction is
0
90 degrees
45 degrees
Equal to the angle of incidence
12176.
The brightness of light source is called its luminous intensity , whose unit is
Candela
Lux
Lumen
Footcandle
12177.
Luminous efficiency is least for a
Low-wattage light bulb
Mercury vapour lamp
High-wattage light bulb
Fluorescent tube
12178.
The minimum illumination recommended for reading is
8000 cd
8000 lx
8000 lm

800W
12179.
Light enters a glass plate whose index of refraction is 1.6 at an angle of incidence
of 30 degrees . the angle of refraction is
18 degrees
48 degrees
19 degrees
53 degrees
12180.
Light leaves a slab of transparent material whose index of refraction is 2 at an
angle of refraction of 0 degrees. The angle of incidence is
0 degrees
45 degrees
30 degrees
90 degrees
12181.
Light enters a glass plate at an angle of incidence of 40 degrees and is refracted at
an angle refraction of 25 degrees. The index refraction of the glass is
0.625
1.52
0.66
1.6
12182.
An underwater swimmer shines a flash light beam upward at an angle of
incidence of 40 degrees. The angle of refraction is 60 degrees. The index of refraction of
water is
0.67
1.3
0.74
1.5
12183.
The critical angle of incidence for light going from crown glass (n=1.5) to ice
(n=1.3) is
12 degrees
50 degrees
42 degrees
60 degrees
12184.
The solid angle subtended by a hemisphere about its ceter is
π/2 sr
2 π sr
π sr
depends on the radius of the hemisphere
12185.
the luminous flux emitted by a 60-cd isotropic light source is concentrated on an
area of 0.5m2. the illumination of the area is
9.6 lx
377 lx
120 lx
1508 lx
12186.
Microwave signals propagate by way of the
Direct wave
Sky wave

Surface wave
Standing wave
12187.
The ionosphere causes radio signals to be
Diffused
Absorbed
Refracted
Reflected
12188.
Ground wave communications is most effective in what frequency range?
300KHz to 3MHz
3 to 30 MHz
30 to 300MHz
Above 300MHz
12189.
The ionosphere has its greatest effect on signals in what frequency range?
300KHz to 3MHz
3 to 30 MHz
30 to 300MHz
Above 300MHz
12190.
The type of radio wave responsible for long distance communications by multiple
skips is the
Groud wave
Direct wave
Surface wave
Sky wave
12191.
Line of sight communications is not a factor in which frequency range?
VHF
UHF
HF
Microwave
12192.
A microwave-transmitting antenna is 550ft high. The receiving antenna is 200ft
high. The minimum transmission distance is
20 mi
33.2 mi
38.7 mi
53.2 mi
12193.
To increase the transmission distance of UHF signal, which of the following
should be done?
Increase antenna gain
Increase antenna height
Increase transmitter power
Increase receiver sensitivity
12194.
States that power density is inversely proportional to the distance from its source.
Principle of reciprocity
Inverse square law
Huygen’s Princple
Faraday’s law
12195.
gets in contact with the ionosphere and reflected by it.

Space wave
Sky wave
Surface wave
Satellite wave
12196.
Highest layer in the ionosphere
F1
D
F2
E
12197.
Next lowest layer in the ionosphere.
D
E
F1
F2
12198.
What is the primary cause of ionization in the atmosphere?
Sun spot
Cosmic rays
Galactic disturbance
Ultraviolet radiation
12199.
Which layer does not disappear at night?
D
E
F1
F2
12200.
Which of the following uses surface wave propagation?
ELF
VLF
MF
All of these
12201.
The ability of the ionosphere to reflect a radio wave back to the earth is
determined by
Operating frequency
Ion density
Angle of incidence
All of these
12202.
Highest frequency that can be used for skywave propagation between two given
points on earth.
Critical frequency
MUF
Cut –off frequency
UHF
12203.
The shortest distance measured along the earth’s surface that a skywave is
returned to earth.
MUF
Quarter-wavelength
Skip distance

Skip zone
12204.
Fluctuation in the signal strength at the receiver.
Interference
Fading
Tracking
Variable frequency
12205.
Two or more antennas are used separated by several wavelengths
Space diversity
Frequency diversity
Hybrid diversity
Polarization diversity
12206.
Two or more receivers are used using a single antenna.
Space diversity
Frequency diversity
Hybrid diversity
Polarization diversity
12207.
One of the following is not a cause of fading.
Interference between upper and lower rays of a sky wave.
Skywaves arriving at different number of hops
Interference due to ground reflected wave and skywave
Diversity
12208.
What do you call the gigantic emissions of hydrogen from the sun?
Solar flares
SIDs
Kennely-Heaviside
Sun spots
12209.
Sudden ionospheric disturbance
Solar flares
SIDs
Sun spots
Intertropical convergence
12210.
A means beyond the line of sight propagation of UHF signals.
Microwave propagation
Space wave propagation
Troposcatter propagation
Surface wave propagation
12211.
Two directional antennas are pointed so that their beams intersect in the
troposphere.
Skywave
Surface wave
Microwave
Troposcatter
12212.
Super refraction.
Ducting
Trposcatter
Skywave

Space wave
12213.
A layer of warm air trapped above cooler air
Troposphere
SID
Duct
Huygen’s principle
12214.
Corresponds to voltage
Electric field
Magnetic field
Gyro
Direction of propagation
12215.
Absence of reception
Skip distance
Maximum usable
Shadow zone
Twilight zone
12216.
Each point in a spherical waveform maybe a source of a secondary spherical
wavefront.
Senll’s law
Huygen’s principle
Rayleigh’s principle
De Morgan’s theore,
12217.
Ducting occurs in which region of the atmosphere?
Stratosphere
Troposphere
Ionosphere
Ozone layer
12218.
When is the E region most ionized?
At midday
At midnight
At duck
At dawn
12219.
Transequatorial propagation is best during
Night time
Afternoon or early evening
Noontime
Morning
12220.
Which of the following is most affected by knife-edge refraction?
Very high and ultra high frequencies
High frequencies
Medium frequency
Low frequency
12221.
Which ionosphere layer has an average height of 225km at night?
D layer
E layer
F1 layer

F2 layer
12222.
12223.
12224.
12225.
12226.
12227.
12228.
12229.
12230.
12231.
12232.
12233.
12234.
12235.
12236.
12237.
12238.
Transmission Fundamentals
12239.
What is the opposition to the transfer of energy which is considered the dominant
characteristic of a cable or circuit that emanates from its physical structure?
12240. Conductance
12241. Resistance
12242. Reactance
12243. Impedance
12244.
When load impedance equals to Zo of the line, it means that the load _____ all the
power.
12245. reflects
12246. absorbs
12247. attenuates
12248. radiates
12249.
impedance matching ratio of a coax balun.
12250. 1:4
12251. 4:1
12252. 2:1
12253. 3:2
12254.
Which stands for dB relative level?
12255. dBrn
12256. dBa
12257. dBr
12258. dBx
12259.
Standard test tone used for audio measurement.
12260. 800 Hz
12261. 300 Hz
12262. 100 Hz
12263. 1000 Hz
12264.
When VSWR is equal to zero, this means

12265. that no power is applied
12266. that the load is purely resistive
12267. that the load is a pure reactance
12268. that the load is opened
12269.
_______ is the ratio of reflected voltage to the forward travelling voltage.
12270. SWR
12271. VSWR
12272. Reflection coefficient
12273. ISWR
12274.
Transmission line must be matched to the load to ______.
12275. transfer maximum voltage to the load
12276. transfer maximum power to the load
12277. reduce the load current
12278. transfer maximum current to the load
12279.
Which indicate the relative energy loss in a capacitor?
12280. Quality factor
12281. Reactive factor
12282. Dissipation factor
12283. Power factor
12284.
What is the standard test tone?
12285. 0 dB
12286. 0 dBW
12287. 0 dBm
12288. 0 dBrn
12289.
The energy that neither radiated into space nor completely transmitted.
12290. Reflected waves
12291. Captured waves
12292. Incident waves
12293. Standing waves
12294.
Micron is equal to _______ meter.
12295. 10-10
12296. 10-9
12297. 10-6
12298. 10-3
12299.
1 Angstrom (A) is equal to _______.
12300. 10-3 micron
12301. 10-10 m
12302. 10-6 micron
12303. 10-6 m
12304.
Why is it impossible to use a waveguide at low radio frequencies?
12305. Because of the size of the waveguide
12306. Due to severe attenuation
12307. Due to too much radiation
12308. All of these
12309.
________ is the transmission and reception of information.
12310. Modulation

12311. Communications
12312. Radiation
12313. Emission
12314.
What is the loss of the circuit in dB if the power ration of output to input is 0.01?
12315. 20
12316. -20
12317. 40
12318. -40
12319.
Transmission lines are either balanced or unbalanced with respect to
12320. Negative terminal
12321. Reference
12322. Ground
12323. Positive terminal
12324.
The standing wave ratio is equal to _______ if the load is properly matched with
the transmission line.
12325. Infinity
12326. 0
12327. -1
12328. 1
12329.
________ is the advantage of the balanced transmission line compared to
unbalanced line.
12330. Low attenuation
12331. Easy installation
12332. Low radiation loss
12333. Tensile strength
12334.
_______ is the method of determining the bandwidth of any processing system.
12335. Fourier series
12336. Spectral analysis
12337. Frequency analysis
12338. Bandwidth analysis
12339.
What causes the attenuation present in a waveguide?
12340. The air dielectric filling the guide
12341. The coating of silver inside
12342. Losses in the conducting walls of the guide
12343. Radiation loss
12344.
A device that converts a balanced line to an unbalanced line of a transmission
line.
12345. Hybrid
12346. Stub
12347. Directional coupler
12348. Balun
12349.
What is the approximate line impedance of a parallel-strip line spaced 1 cm apart
with the length of 50 cm?
12350. 10 ohms
12351. 15 ohms
12352. 18 ohms

12353. 23 ohms
12354.
What is the average power rating of RG-58 C/u?
12355. 25 W
12356. 50 W
12357. 75 W
12358. 200 W
12359.
A coaxial cable used for high temperatures.
12360. RG-58C
12361. RG-11A
12362. RG-213
12363. RG-211
12364.
If you have available number of power amplifiers with a gain of 100 each, how
many such amplifiers do you need to cascade to give an overall gain of 60dB?
12365. 2
12366. 3
12367. 4
12368. 5
12369.
You are measuring noise in a voice channel at a -4 dB test point level, the meter
reads -73 dBm, convert the reading into dBrnCO.
12370. 12
12371. 16
12372. 18
12373. 21
12374.
The velocity factor for a transmission line
12375. depends on the dielectric constant of the material used
12376. increases the velocity along the transmission line
12377. is governed by the skin effect
12378. is higher for a solid dielectric than for air
12379.
Impedance inversion can be obtained by
12380. a short-circuited stub
12381. an open-circuited stub
12382. a quarter-wave line
12383. a half-wave line
12384.
Transmission lines when connected to antennas have
12385. capacitive load
12386. resistive load whose resistance is greater than the characteristic impedance of the
line
12387. resistive load whose resistance is less than the characteristic impedance of the line
12388. resistive load at the resonant frequency
12389.
One of the following is not a bounded media.
12390. Coaxial line
12391. Two-wire line
12392. Waveguide
12393. Ocean
12394.
The impedance measured at the input of the transmission line when its length is
infinite.

12395. Input impedance
12396. Open circuit impedance
12397. Characteristic impedance
12398. Short circuit impedance
12399.
The following are considered primary line constants except
12400. conductance
12401. resistance
12402. capacitance
12403. complex propagation constant
12404.
The dielectric constants of materials commonly used in transmission lines range
from about
12405. 1.2 to 2.8
12406. 2.8 to 3.5
12407. 3.5 to 5.2
12408. 1.0 to 1.2
12409.
Typically, the velocity factor (VF) of the materials used in transmission lines range
from
12410. 0.6 to 0.9
12411. 0.1 to 0.5
12412. 1.0 to 0.9
12413. 0.6 to 0.8
12414.
For an air dielectric two-wire line, the minimum characteristic impedance value is
12415. 85 ohms
12416. 85 ohms
12417. 90 ohms
12418. 88 ohms
12419.
When a quarter-wave section transmission line is terminated by a short circuit and
is connected to an RF source at the other end, its input impedance is
12420. inductive
12421. capacitive
12422. resistive
12423. equivalent to a parallel resonant LC circuit
12424.
A transmitter operating at 30 MHz with 4 W output is connected via 10 m of RG8A/u cable to an antenna that has an input resistance of 300 ohms. Find the reflection
coefficient.
12425. 0.71
12426. 0.77
12427. 0.97
12428. 0.76
12429.
A quarter wave transformer is connected to a parallel wire line in order to match
the line to a load of 1000 ohms. The transformer has a characteristic impedance of 316.23
ohms. The distance between centers is 4 inches. What is the percentage reduction in the
diameter of the line?
12430. 85%
12431. 83%
12432. 86%

12433. 90%
12434.
The concept used to make one Smith chart universal is called
12435. ionization
12436. normalization
12437. rationalization
12438. termination
12439.
What are the basic elements of communications system?
12440. Source, transmission channel, transmitter
12441. Transmitter, receiver, transmission channel
12442. Information, transmission channel, receiver
12443. Sender and receiver
12444.
________ is the transmission of printed material over telephone lines.
12445. Internet
12446. Data communication
12447. Telegraphy
12448. Facsimile
12449.
________ is a continuous tone generated by the combination of two frequencies
of 350 Hz and 440 Hz used in telephone sets.
12450. DC tone
12451. Ringing tone
12452. Dial tone
12453. Call waiting tone
12454.
________ are unidirectional amplifiers having 20-25 decibel gain that are placed
about 75 km apart used to compensate for losses along the telephone line.
12455. VF repeaters
12456. Loading coils
12457. Loop extenders
12458. Echo suppressors
12459.
________ is a component in the telephone set that has the primary function of
interfacing the handset to the local loop.
12460. Resistor
12461. Capacitor
12462. Varistor
12463. Induction coil
12464.
Pulse dialing has ________ rate.
12465. 20 pulses/min
12466. 10 pulses/min
12467. 10 pulses/sec
12468. 80 pulses/sec
12469.
________ is a telephone wire that connects two central offices.
12470. 2-wire circuit
12471. Trunk line
12472. Leased line
12473. Private line
12474.
The central switching office coordinating element for all cell sites that has cellular
processor and a cellular switch. It interfaces with telephone company zone offices,

control call processing and handle billing activities.
12475. MTSO
12476. Cell site
12477. PTSN
12478. Trunk line
12479.
________ in a cellular system performs radio-related functions for cellular site.
12480. Switching system
12481. Base station
12482. Operation and support system
12483. Mobile station
12484.
A technology used to increase the capacity of a mobile phone system.
12485. Frequency re-use
12486. Cell splitting
12487. TDM
12488. FDM
12489.
If the grade of service of a telephone system indicated P = 0.05, what does it
mean?
12490. Completed calls of 5%
12491. Lost calls of 5%
12492. Lost calls of 95%
12493. Lost calls of 105%
12494.
________ is the Out-of-Band signaling between Toll Central Offices (Bell System
Standard).
12495. 3, 825 Hz
12496. 3, 700 Hz
12497. 2, 600 Hz
12498. 800 Hz
12499.
In a telephone system, the customer’s telephone directory numbering is from 000
to 999, what is the capacity of a telephone system numbering from 000 to 999?
12500. 100 lines
12501. 1000 lines
12502. 10, 000 lines
12503. 100, 000 lines
12504.
If the SWR is infinite, what type of load transmission line has?
12505. Purely reactive
12506. Purely resistive
12507. Purely capacitive
12508. Purely inductive
12509.
Not more than _______ digits make up an international telephone number as
recommended by CCITT REC. E. 161.
12510. 8
12511. 10
12512. 11
12513. 12
12514.
One (1) Erlang is equal to _______.
12515. 360 CCS

12516. 36 CCS
12517. 3.6 CCS
12518. 100 CCS
12519.
Standard tariff for flat rate telephone service beyond the normal flat rate in that
area.
12520. WATS
12521. OTLP
12522. TIP
12523. DTWX
12524.
The standard analog telephone channel bandwidth.
12525. 300-3400 Hz
12526. 1200 Hz
12527. 200-3200 Hz
12528. 300-3000 Hz
12529.
Type of switching in which a pair of wire from the telephone set terminates in a
jack and the switch is supervised by an operator.
12530. Crossbar switching
12531. Manual switching
12532. Electronic switching
12533. Step-by-step switching
12534.
Every time when the telephone is idle, the handset is in the _______ state.
12535. On-hook
12536. Off-hook
12537. Busy
12538. Spare
12539.
_______ is a component in the telephone set that has the primary function of
compensating for the local loop length.
12540. Resistor
12541. Varistor
12542. Capacitor
12543. Induction coil
12544.
What kind of receiver is used in conventional telephone handset?
12545. Carbon
12546. Electromagnetic
12547. Ceramic
12548. Capacitor
12549.
A voice-grade circuit using the PTN ha an ideal passband of
12550. 0 to 4 Hz
12551. 0 to 4 MHz
12552. 0 to 4 kHz
12553. 0 to 4 GHz
12554.
________ is the minimum-quality circuit available using the PTN.
12555. Basic voice grade (VG)
12556. Basic voice channel (VC)
12557. Basic voice band (VB)
12558. Basic telephone channel

12559.
Direct distance dialing (DDD) network is called
12560. Private-line network
12561. PT network
12562. Dial-up network
12563. Trunk network
12564.
What is the advantage of sidetone?
12565. Transmission efficiency is increased
12566. Speaker increases his voice resulting in a strengthened signal
12567. No dissipation of energy in the balancing network
12568. Assure the customer that the telephone is working
12569.
________ is a special service circuit connecting two private branch exchanges
(PBX).
12570. Phantom line
12571. Tie trunk
12572. Tandem trunk
12573. Private line
12574.
The published rates, regulation, and descriptions governing the provision of
communications service for public use.
12575. Toll rate
12576. Tariff
12577. Bulk billing
12578. Detailed billing
12579.
What is the power loss of a telephone hybrid?
12580. 1 dB
12581. 2 dB
12582. 3 dB
12583. 6 dB
12584.
Telephone channel has a band-pass characteristic occupying the frequency range
of _______.
12585. 300-400 Hz
12586. 300-3400 Hz
12587. 300-3000 Hz
12588. 300-2700 Hz
12589.
The first Strowger step-by-step switch was used in _______.
12590. 1875
12591. 1890
12592. 1897
12593. 1913
12594.
What is the phase delay of an 800 Hz voice signal if the phase shift is 15 degrees?
12595. 52usec
12596. 1.25usec
12597. 83.33usec
12598. 26usec
12599.
What is the CCITT recommendation for a preparation of loss plan, a variable loss
plans and a fixed loss plan?
12600. G. 133

12601. G. 141
12602. G. 132
12603. G. 122
12604.
What is the diameter of a copper wire to be used in a 16 km loop with a dc loop
resistance of 100 ohms/km?
12605. 0.838 mm
12606. 0.465 mm
12607. 1.626 mm
12608. 2.159 mm
12609.
What kind of cell is appropriate for load management, fast moving mobiles and
low-usage areas?
12610. Pico cells
12611. Micro cells
12612. Nano cells
12613. Umbrella cells
12614.
In cellular networks, standard base station antennas are placed by _______.
12615. adaptive array
12616. flat plate antenna
12617. dipole array
12618. focused antenna
12619.
What is the basis of the first generation wireless local loop?
12620. Digital cellular technology
12621. Analogue cellular technology
12622. PSTN
12623. AMPS technology
12624.
When the calling party hears a “busy” tone on his telephone, the call is considered
12625. lost
12626. disconnected
12627. completed
12628. incomplete
12629.
Short-circuited stubs are preferred to open circuited stubs because the latter are
12630. more difficult to make and connect
12631. made of a transmission line with a different characteristic impedance
12632. liable to radiate
12633. incapable of giving a full range of reactances
12634.
What is the ratio of the reflected voltage to the incident voltage?
12635. VSWR
12636. ISWR
12637. SWR
12638. Coefficient of reflection
12639.
One method of determining antenna impedance.
12640. Sub matching
12641. Trial and error
12642. Smith chart
12643. Quarter-wave matching
12644.
________ is a single conductor running from the transmitter to the antenna.

12645. Single-wire line
12646. Microstrip
12647. Twin-lead
12648. Coaxial line
12649.
Coaxial cable impedance is typically _______.
12650. 150 to 300 ohms
12651. 50 to 75 ohms
12652. 30 to 45 ohms
12653. 300 to 600 ohms
12654.
Waveguide becomes compulsory above what frequencies?
12655. Above 3 GHz
12656. Above 10 kHz
12657. At 300 MHz
12658. Above 10 GHz
12659.
Nominal voice channel bandwidth is _______.
12660. 20 to 30 kHz
12661. 0 to 3 kHz
12662. 4 kHz
12663. 55 kHz above
12664.
Echo suppressors are used on all communications system when the round trip
propagation time exceeds _______.
12665. 50 ms
12666. 30 ms
12667. 100 ms
12668. 1 ms
12669.
A radio transmission line of 300 ohms impedance is to be connected to an antenna
having an input impedance of 150 ohms. What is the impedance of a quarter-wave
matching line?
12670. 212 ohms
12671. 250 ohms
12672. 200 ohms
12673. 150 ohms
12674.
Quarter-wavelength line is used as _______.
12675. impedance transformer
12676. lecher line
12677. transmission line
12678. harmonic suppressor
12679.
The transmission lines which can convey electromagnetic waves only in higher
modes is usually called
12680. coaxial cable
12681. waveguide
12682. power lines
12683. twisted wire of telephone line
12684.
Why is nitrogen gas sometimes used in waveguide?
12685. To increase the distributed capacitance
12686. To keep the waveguide dry

12687. To reduce the skin effect at the walls of the guide
12688. To raise the guide’s wave impedance
12689.
The apparent speed of propagation along a waveguide based on the distance
between wavefronts along the walls of the guide is called
12690. group velocity
12691. phae velocity
12692. normal velocity
12693. abnormal velocity
12694.
How do you couple in and out of a waveguide?
12695. Wrap a coil of wire around one end of the waveguide
12696. Insertion of an E-probe into the waveguide
12697. Insertion of an H-loop into the waveguide
12698. Both B and C
12699.
A rectangular waveguide is operating in the dominant TE10 mode. The associated
flux lines are established
12700. transversely across the narrow dimension of the waveguide
12701. transversely across the wide dimension of the waveguide
12702. in the metal walls parallel to the direction of propagation
12703. in the metal walls perpendicular to the direction of propagation
12704.
For dominant mode of a rectangular waveguide, the distance between two
instantaneous consecutive positions of maximum field intensity (in a direction parallel to
the walls of the waveguide) is referred to as half of the
12705. free-space wavelength
12706. cutoff wavelength in the wide dimension
12707. guide wavelength
12708. group wavelength
12709.
The guide wavelength, in a rectangular waveguide is
12710. equal to the free-space wavelength at the cutoff frequency
12711. equal to the free-space wavelength for the same signal frequency
12712. less than the free-space wavelength at the cut-off frequency
12713. greater than the free-space wavelength at the same signal frequency
12714.
Using the TE10 mode, microwave power can only be transmitted in free
rectangular guide provided
12715. the wider dimension is less than one-half of the wavelength in free space
12716. the narrow dimension is less than one-quarter of the wavelength in free space
12717. the wide dimension is greater than one-half of the guide wavelength
12718. the wide dimension is greater than one-half of the wavelength in free space
12719.
If the signal frequency applied to a rectangular guide is increased and the
dominant mode is employed
12720. the free space wavelength is increased
12721. the phase velocity increased
12722. the guide wavelength is increased
12723. the group velocity, Vg, is increased
12724.
If a 6 GHz signal is applied to a rectangular waveguide and the reflection angle is
20o, what is the value of the guide wavelength?
12725. 6.10 cm

12726. 5.32 cm
12727. 4.78 cm
12728. 5.00 cm
12729.
The inner dimensions of a rectangular wavelength are 1.75 cm by 3.5 cm. The
cutoff wavelength for the dominant mode is
12730. 1.75 cm
12731. 3.5 cm
12732. 7.0 cm
12733. 0.4375 cm
12734.
A signal whose wavelength is 3.5 cm is being propagated along a guide whose
inner dimensions are 2 cm by 4 cm. What is the value of the guide wavelength?
12735. 3.12 cm
12736. 3.89 cm
12737. 3.57 cm
12738. 6.30 cm
12739.
The frequency range over which a rectangular waveguide is excited in the
dominant mode is limited to
12740. the difference between the frequency for which the reflection angle is 90o and the
frequency for which angle is zero
12741. the difference between the frequency for which the free-space wavelength is equal
to the cutoff value and the frequency for which the free-space wavelength is equal to
the guide wavelength
12742. the difference between the frequency at which the cutoff wavelength is twice
the narrow dimension
12743. none of these
12744.
If a rectangular waveguide is to be excited in the dominant mode, the E-probe
should be inserted
12745. at the sealed end
12746. at a distance of one quarter –wavelength from the sealed end
12747. at a distance of one-half wavelength from the sealed end
12748. at a distance of three-quarters of a wavelength from the sealed end
12749.
A quarter-wave line is connected to an RF generator and is shorted out at the far
end. What is the input impedance to the line generator?
12750. A low value of resistance
12751. A high value of resistance
12752. A capacitive resistance which is equal in the value to the line’s surge impedance
12753. An inductive resistance which is equal to the value to the line’s surge impedance
12754.
If the SWR on a transmission line has a high value, the reason could be
12755. an impedance mismatch between the line and the load
12756. that the line is non-resonant
12757. a reflection coefficient of zero at the load
12758. that the load is matched to the line
12759.
If a quarter-wave transmission line is shorted at one end
12760. there is minimum current at the shorted end
12761. the line behaves as a parallel-tuned circuit in relation to the generator
12762. the line behaves as a series-tuned circuit in relation to the generator

12763. there is a minimum voltage at the shorted end
12764.
A 50-ohm transmission line is feeding an antenna which represents a 50 ohm
resistive load. To shorten the line, the length must be
12765. any convenient value
12766. an odd multiple of three quarters of a wavelength
12767. an odd multiple of half a wavelength
12768. an even multiple of a quarter of a wavelength
12769.
The outer conductor of the coaxial cable is usually grounded
12770. at the beginning and at the end of the cable
12771. only at the beginning of the cable and only at the end of the cable
12772. only at the end of the cable
12773. at the middle of the cable
12774.
A feature of an infinite transmission line is that
12775. its input impedance at the generator is equal to the line’s surge impedance
12776. its phase velocity is greater than the velocity of light
12777. no RF current will be drawn from the generator
12778. the impedance varies at different positions on the line
12779.
When the surge impedance of a line is matched to a load, the line will
12780. transfer maximum current to the load
12781. transfer maximum voltage to the load
12782. transfer maximum power to the load
12783. have a VSWR equal to zero
12784.
A lossless line is terminated by a resistive load which is not equal to the surge
impedance. If the value of the reflection coefficient is 0.5, the VSWR is
12785. 2
12786. 3
12787. 4
12788. 15
12789.
Ratio of the mismatch between the antenna and the transmitter power.
12790. Standing wave pattern
12791. Reflection coefficient
12792. SWR
12793. Index of refraction
12794.
Emission designation for a facsimile.
12795. H3E and A4E
12796. R3E and A4E
12797. F4E and J3E
12798. F3C and A3E
12799.
Commonly used telephone wire.
12800. AWG #19
12801. AWG #18
12802. AWG #30
12803. AWG #33
12804.
What is the distance traveled by a wave in the time of one cycle?
12805. Frequency
12806. Hop

12807. Wavelength
12808. Crest
12809.
The velocity factor is inversely proportional with respect to the _______.
12810. square of the dielectric constant
12811. square root of the dielectric constant
12812. dielectric current
12813. square root of refractive index
12814.
________ is a hollow structure that has no center conductor but allows waves to
propagate down its length.
12815. Waveguide
12816. Hybrid
12817. Pipe
12818. Directional coupler
12819.
To connect a coaxial line to a parallel wire line, _______ is used.
12820. hybrid circuit
12821. balun
12822. directional coupler
12823. quarter-wave transformer matching circuit
12824.
What length for which the input power has been halved for a transmission line
with an attenuation of 6 dB/km?
12825. 1.5 km
12826. 0.5 km
12827. 63 km
12828. 2 km
12829.
Ina waveguide, _______ is a specific configuration of electric and magnetic fields
that allows a wave to propagate.
12830. set-up
12831. coupler
12832. channel
12833. mode
12834.
A rectangular waveguide has dimensions of 3 cm x 5 cm. What is the dominant
mode cut-off frequency?
12835. 2 GHz
12836. 3 GHz
12837. 2.5 GHz
12838. 3.5 GHZ
12839.
________ are transmission lines which can convey electromagnetic waves only in
higher order modes?
12840. Coaxial cables
12841. Twisted pairs of telephone wire
12842. Power cables
12843. Waveguides
12844.
The amount of uncertainty in a system of symbols is also called
12845. bandwidth
12846. loss
12847. entropy

12848. quantum
12849.
The twists in twisted wire pairs
12850. reduced electromagnetic interference
12851. occur at a 30-degree angle
12852. eliminate loading
12853. were removed due to cost
12854.
An example of a bounded medium is
12855. coaxial cable
12856. waveguide
12857. fiber-optic cable
12858. all of the above
12859.
Loading means the addition of
12860. resistor
12861. capacitor
12862. bullet
12863. inductance
12864.
What is the most commonly used transmission line for high frequency
application?
12865. Two-wire balance line
12866. Single wire
12867. Three-wire line
12868. Coaxial
12869.
The characteristic impedance of a transmission line does not depend upon its
12870. length
12871. conductor diameter
12872. conductor spacing
12873. dielectric material
12874.
One of the following is not a common transmission line impedance.
12875. 50 ohms
12876. 75 ohms
12877. 120 ohms
12878. 300 ohms
12879.
For maximum absorption of power at the antenna, the relationship between the
characteristic impedance of the line Zoand the load impedance ZL should be
12880. Zo = ZL
12881. Zo > ZL
12882. Zo < ZL
12883. Zo = 0
12884.
The mismatch between antenna and transmission line impedance cannot be
corrected for by
12885. using LC matcging network
12886. adjusting antenna length
12887. using a balun
12888. adjusting the length of transmission line
12889.
________ is a pattern of voltage and current variations along a transmission line
not terminated in its characteristic impedance.

12890. An electric field
12891. Radio waves
12892. Standing waves
12893. A magnetic field
12894.
Which is the desirable SWR on a transmission line?
12895. 0
12896. 1
12897. 2
12898. Infinity
12899.
A 50ohm coax is connected to a 73-ohm antenna. What is the SWR?
12900. 0.685
12901. 1
12902. 1.46
12903. 2.92
12904.
What is the most desirable reflection coefficient?
12905. 0
12906. 0.5
12907. 1
12908. Infinity
12909.
What is the ratio expressing the percentage of incident voltage reflected on a
transmission line?
12910. Velocity factor
12911. Standing-wave ratio
12912. Reflection coefficient
12913. Line efficiency
12914.
The minimum voltage along a transmission line is 260 V, while the maximum is
390 V, the SWR is
12915. 0.67
12916. 1.0
12917. 1.2
12918. 1.5
12919.
One meter is one wavelength at a frequency of
12920. 150 MHz
12921. 164 MHz
12922. 300 MHz
12923. 328 MHz
12924.
At very high frequencies, transmission lines act as
12925. Tuned circuits
12926. Antennas
12927. Insulators
12928. Resistors
12929.
A shorted quarter-wave line at the operating frequency acts like a/an
12930. Capacitor
12931. Inductor
12932. Series resonant circuit
12933. Parallel resonant circuit

12934.
A shorted half-wave line at the operating frequency acts like a/an
12935. Capacitor
12936. Inductor
12937. Series resonant circuit
12938. Parallel resonant circuit
12939.
A medium least susceptible to noise?
12940. Shielded pair
12941. Twisted pair
12942. Fiber-optic
12943. Coaxial
12944.
A medium most widely used in LANs?
12945. Parallel-wire line
12946. Twisted pair
12947. Fiber-optic cable
12948. Coaxial
12949.
The most commonly used transmission line in television system.
12950. Parallel-wire line
12951. Coaxial cable
12952. Waveguide
12953. Open-wire ceramic supports
12954.
The impedance of a TV transmission line depends on several factors. Which is not
one of those factors?
12955. Diameter
12956. Length of the wire
12957. Dielectric material
12958. Separation between conductors
12959.
DC blocks are used in coaxial transmission line for the purpose of
12960. passing DC while blocking AC
12961. passing AC voltage but prevent DC
12962. preventing AC voltage from reaching the pre-amplifier
12963. preventing AC power supply voltage from being shorted by a balun or band
splitter
12964. _______ is a type of interference caused by off-air TV channels 2 and 4, plus a
satellite dish operating on channel 3.
12965. Adjacent channel interference
12966. Ghost
12967. Co-channel interference
12968. Crosstalk
12969. Dithering (in TVRO communication) is a process of
Reducing the effect of noise on the TVRO video signal
Centering the video fine tuning on TVRO channels
Moving the feedhorn rotor to the precise angle
Moving the actuator exactly onto the desired satellite beam
12970. A network that has an input of 75dB and an output of 35dB. The loss of the network
is
-40db

40db
40dBm
-4dBm
12971. Important useful quantities describing waveforms.
Time and frequency
Voltage and current
Frequency and voltage
Power and frequency
12972. Halving the power means
6-dB gain
3-dB loss
3-dB gain
6-dB loss
12973. One Neper (Np) is how many decibels?
8.866
8.686
8.688
8.868
12974. A signal is amplified 100 times in power. The dB gain is
20dB
119dB
15dB
25dB
12975. Which of the following is used to measure SWR?
Spectrum analyzer
Reflectometer
Oscilloscope
Multimeter
12976. 214-056 twin lead which is commonly used for TV lead-in has a characteristic
impedance of
52 ohms
75 ohms
600 ohms
300 ohms
12977. What is the characteristic impedance of a transmission line which is to act a s a
quarterwave matching transformer between a 175 ohms transmission line and 600
ohms load?
300.04 ohms
324.04 ohms
310.04 ohms
320.04 ohms
12978. What is the EIRP in dBW of a 50dB antenna connected to a transmitter with an
output of 10kW through a transmission line with loss of 5dB?
85dBW
955 dBW
90 dBW

80 dBW
12979. A coaxial cable is a good example of a/an
Unbounded medium
Transmission channel
Non-metallic medium
Bounded medium
12980. If a quarterwave transformer is required to match a 180 ohm load to a transmission
line with and impedance of 300 ohms, what should be the characteristic impedance of
the matching ransformer? Assume that the matching transformer is to be connected
directly to the load.
180 ohms
232 ohms
300 ohms
480 ohms
12981. A transmitter of 100W RF power output, 100% modulated is operating on a
frequency of 169MHz. The antenna transmission line consists of a 50 ohms coaxial
cable 150ft long. The coaxial inner conductor outer diameter is 0.162in. determine
the outside diameter of the outer conductor if the outer conductor has a thickness of
0.05 in(assume K=1).
1.0 in
0.9in
0.7in
0.5in
12982. In the preceding problem , calculate the line current.
1.7A
1.3A
1.5A
1.0A
12983. Determine also the total attenuation of the line in the preceding problem.
2.0dB
1.5 dB
2.5 dB
1.0 dB
12984. What is the maximum subscriber loop length, in ft, of a telephone system if the
signalling resistance is 1800ohms using a telephone cable pair of gauge #26 with
loop resistance of 83.5 ohms per 100ft. Assume the telephone set resistance is equal
to 200 ohms.
15,161.7 feet
19,161 feet
15,300 feet
20,000 feet
12985. If the same subscriber loop above limits the voice attenuation to a maximum of 6dB,
what is the maximum allowable subscriber loop length, in feet, using the same gauge
#26 telephone wire? Assume a 2.7dB loss per mile.
20,000 ft
13,900 ft

15,280ft
11,733ft
12986. The input is 0.1W and the network gain is 13dB, the output is
2.0W
2.5W
1.5W
1.8W
12987. Known as one-tenth of a neper.
dB
dBm
dBp
dNp
12988. the input impedance of a quarterwave short-circuited transmission line at its resinant
frequency is
0 ohms
Infinite or an open circuit
Ohm
70 ohms
12989. The ratio of the largest rms value to the smallest rms value of the voltage in the line is
called
SWR
ISWR
VSWR
Coefficient of reflection
12990. An open-wire, two-wire transmission line is to be connected to a dipole antenna
through a quarter-wave matching stub. At a frequency of 10 MHz, compute the
length of the dipole
20 meters
7.5 meters
15 meters
25 meters
12991. From the preceding problem, compute also the length of the quarterwave stub.
15 meters
7.5 meters
20 meters
25 meters
12992. To find the characteristic impedance of a coaxial cable, measurements are made with
(a) the far end open circuited and (b) far end short circuited, the corresponding
readings being a) Ro=3ohms and Xc=55 ohms, capacitive b) RS = 10 ohms and XL =
90 ohms, inductive. What is the characteristic impedance Zo of the line?
75.7-j2.0 ohms
70.7+j1.19 ohms
87.5 – j5 ohms
70.7 – j1.97 ohms
12993. A TV antenna receives a signal measured at 200mV and is immediately amplified by
a preamplifier with a 15dB gain. This amplified signal then passes through a coaxial

cable with 3dB loss, what is the resulting input to the TV set, in dBmV?
1.98
13.98
-1.98
-13.98
12994. The characteristic impedance of a transmission line does not depend upon
its___________.
Conductor spacing
Conductor diameter
Length
Conductor radius
12995. What does a power difference of -3dB mean?
A loss of one third of the power
A loss of one half of the power
A loss of three watts of power
No significant change
12996. Which of the following is an advantage of the balance transmission line?
Easy installation
Outer shield eliminates radiation losses
Low attenuation
None of these
12997. Waveguides are used mainly for microwave transmission because
They are bulky at lower frequencies
Losses are heavy at lower frequencies
They depend on straight line propagation
No generators are powerful enough to excite them
12998. The input is 1W and the network loss is 27dB, the output is
1mW
3mW
2mW
4mW
12999. A combiner has two inputs +30dBm and +30dBm, what is the resultant output?
+36 dBm
+30 dBm
+60 dBm
+33 dBm
13000. The ratio of the smallest to the largest rms current value is called
SWR
VSWR
ISWR
Coefficient of reflection
13001. If the ratio of the maximum current to minimum current in a transmission line is 2:1
then the ratio of the maximum voltage to minimum voltage is
4:1
1:2
1:4

2:1
13002. Two wires of 600 ohms characteristic impedance is to be constructed out of a number
12 wire (81 mils). Find the attenuation of the line at 0.6GHz per 100feet length
0.05 dB
0.55 dB
0.44 dB
0.35 dB
13003. In the preceding problem, determine the spacing between wires from center to center.
6 in
4 in
5 in
3 in
13004. A lossless transmission line has a shunt capacitance of 100nF/m and a series
inductance of 4mH/m. What is the characteristic impedance?
500 ohms
400ohms
300ohms
200hms
13005. A ten times power change in transmission system is equivalent to
10dBm
1dB
20dB
100dB
13006. A type of transmission line employed where balanced properties are required.
Balun
Parallel-wire line
Coaxial line
Quarterwave line
13007. What is the characteristic impedance of a transmission line which has a capacitance
of 40nF/ft and an inductance of 0.5mH/ft
111.8 ohms
110.8 ohms
112.8 ohms
109.8 ohms
13008. The input power to a loss-free cable is 5W. If the reflected power is 7dB down on the
incident power, the output power to the load is
4W
5W
6W
7W
13009. To be properly matched the ratio of a maximum voltage along a transmission line
should be equal to
1
10
50
2

13010. A coaxial line with an outer diameter of 6mm has a 50 ohms characteristic
impedance. If the dielectric constant of the insulation is 1.60., calculate the inner
diameter.
2.09cm
2.09in
2.09mm
2.09mm
13011. If an amplifier has equal input and out impedance, what voltage ratio does the gain of
50dB represent?
316.2
325.2
320.1
315.0
13012. What is the inductance per foot of a cable that has a capacitance of 50 pF/ft and a
characteristic impedance of 60 ohms?
0.167uH/ft
0.178 uH/ft
0.19 uH/ft
0.18 uH/ft
13013. The ratio between the energy absorbed by a surface to the total energy received by
the surface.
Reflection coefficient
Absorption coefficient
Linear coefficient
Thermal coefficient
13014. When the diameter of the conductors of a wire transmission line is held constant, the
effect of decreasing the distance between the conductors is
Increase the surge impedance
Increase the radiation resistance
Decrease the SWR
Decrease the impedance
13015. The higher the gauge number if a conductor
The bigger the diameter
The higher the resistance or the smaller the diameter
The higher the resistance
None of the above
13016. A short length transmission line used to reduce/eliminate standing waves in the main
transmission line.
Stub
Balun
λ/4 transformer
slot
13017. ratio of reflected power to incident power?
Incidence
Reflectance
Reflection index

None of these
13018. A quarter wave transformer is used to match a 600 ohms lad antenna to a ling of 52
ohms impedance, the characteristic impedance of the matching transformer is
200 ohms
150 ohms
176 ohms
300 ohms
13019. What is the capacitance of 55 miles #44 copper wire spaced 18 inches? From wire
tables, #44 wire has a radius to 0.10215 in.
0.476uF
0.476nF
0.476pF
0.476fF
13020. A two-transmission line consists of No. 12 wire AWG (81mils). The distance between
wire centers is 10 inches. What is the characteristic impedance of the line?
650 ohms
300 ohms
600 ohms
660 ohms
13021. In the preceding problem, what is the attenuation in dB per 100ft of the line for a
frequency of 4 MHz?
0.05
0.03
0.04
0.06
13022. What is the SWR when a transmission line is terminated in a short circuit?
Zero
One
Infinite
indeterminate
13023.
13024.
13025.
13026.
13027.
13028.
13029.
13030.
13031. Typical speech power
13032. 10 to 1000 µW
13033. 100 to 1000 mW
13034. 10 to 1000 nW
13035. 100 to 1000 pW
13036. The maximum intelligibility for voice frequency is located between
13037. 250 and 500 Hz

13038. 1000 and 3000 Hz
13039. 500 and 1000 Hz
13040. 3000 and 5000 Hz
13041. The maximum voice energy is located between
13042. 250 and 500 Hz
13043. 1000 and 3000 Hz
13044. 500 and 1000 Hz
13045. 3000 and 5000 Hz
13046. A device used to measure speech volume.
13047. speech meter
13048. volume meter
13049. volume unit meter
13050. speedometer
13051. By definition, for a sine wave
13052. 0 dBm = 0 V.U.
13053. 0 dBW = 0 V.U.
13054. 0 dBa = 0 V.U.
13055. 0 dBf = 0 V.U.
13056. Presently, this is the “standard” frequency bandwidth for voice transmission.
13057. 0 to 4000 Hz
13058. 100 to 3400 Hz
13059. 300 to 3400 Hz
13060. 300 to 3000 Hz
13061. Which of the following is commonly used wire for subscriber loop design?
13062. AWG # 19
13063. AWG # 18
13064. AWG # 30
13065. AWG # 33
13066. The resistance limit for No. 2 Crossbar Exchange (US) is
13067. 1300 Ω
13068. 2000 Ω
13069. 1250 Ω
13070. 1200 Ω
13071. AWG # 26 has a typical loss of
13072. 0.21 dB/1000 ft.
13073. 0.32 dB/1000 ft.
13074. 0.41 dB/1000 ft.
13075. 0.51 dB/1000 ft.
13076. What is the standard voice channel spacing?
13077. 44 MHz
13078. 40 kHz
13079. 4 kHz
13080. 40 MHz
13081. Which tester is used to measure SWR?
13082. Multimeter
13083. Oscilloscope

13084. Spectrum analyzer
13085. Reflectometer
13086. What is singing?
13087. The result of intermodulating two or more signals of different frequencies to
produce a tone having a frequency equal to the sum of the frequencies of the signals
intermodulated.
13088. The result of intermodulating two or more signals of different frequencies to
produce a tone having a frequency higher than that of the signal having the highest
frequency.
13089. An undesired self-sustained oscillation in a system, generally caused by
excessive positive feedback.
13090. An art or form of entertainment that can make one rich.
13091. Which stage increases the selectivity of the circuit in an AM receiver?
13092. Detector
13093. IF stage
13094. Modulator
13095. Mixer
13096. The ________ of radio receiver amplify weak signal and produce a desirable
intelligence at the output speaker.
13097. sensitivity
13098. selectivity
13099. reliability
13100. fidelity
13101. Full-duplex transmission means
13102. One-way transmission
13103. 24-hour transmission
13104. Broadcast transmission
13105. Two-way simultaneous transmission
13106. What is a multidrop line?
13107. A piece of wire with a thick insulating material that serves to protect the
conductive materials from damage in the event the wire is dropped.
13108. A line designed to withstand high pressure.
13109. A line or circuit interconnecting several situations.
13110. A bus line
13111. A passive _________ is an electronic device which reduces signal strength by a
specified amount in dB.
13112. Splitter
13113. Filter
13114. Trimmer
13115. Attenuator
13116. The signal quality of the calls is constantly monitored by the base station, when
the quality of the calls drops below a certain specified level. The base request the MTSO
to try and find a better cell site.
13117. Hand-off
13118. Cell splitting
13119. Roaming

13120. Frequency reuse
13121. A digital identification associated with a cellular system.
13122. SAT
13123. SID
13124. ESN
13125. MIN
13126. How many seconds does facsimile transmit a stranded page?
13127. 5
13128. 10
13129. 20
13130. 25
13131. A kind of recording used in facsimile.
13132. Electrolytic recording
13133. Electrothermal recording
13134. Electropercussive recording
13135. Electrostatic recording
13136. A type of distortion a facsimile produce when it becomes out of synchronization?
13137. Pincushion
13138. Barrel
13139. Skewing
13140. Fattening
13141. What is an acoustic coupler?
13142. A device that radiates audible signals via a transmitting antenna
13143. A device that converts electric signals into audio signals, enabling data to be
transmitted over the public telephone network via a conventional telephone
handset
13144. A device that receives audible signals and retransmits them at VHF frequencies
13145. A transducer
13146. Cause a herringbone pattern in facsimile
13147. Single-frequency interference
13148. Crosstalk
13149. Phase jitter
13150. Noise
13151. The _______ in an FM receiver causes a stronger signal to dominate over a
weaker signal on the same frequency.
13152. Capture effect
13153. Flywheel effect
13154. Hall effect
13155. Skin effect
13156. A device that converts a 2-wire circuit to a 4-wire circuit.
13157. RS-232 interface
13158. Hybrid circuit
13159. Balun
13160. Stub
13161. ______ theory is deciding between a set of hypothesis when given a collection of
imperfect measurements.

13162. Estimation
13163. Traffic
13164. Decision
13165. Nyquist
13166. ______ of a data reduction says that when reducing a set of data into the form of
an underlying mode, one should be maximally non-committal with respect to missing
data.
13167. Jaynes maximum entropy principle
13168. Kullback principle of minimum discrimination
13169. Minimum discrimination\
13170. Maximum entropy
13171. _______ is selecting the best value of a parameter from a continuum of possible
values when gives a collection if imperfect measurements
13172. Estimation
13173. Traffic
13174. Decision
13175. Nyquist
13176. Combination of madulator, channel, and detector.
13177. Transceiver
13178. Transponder
13179. T/R channel
13180. Discrete channel
13181. What is the frequency band of DECT?
13182. 1.88 – 1.90 GHz
13183. 1.68 – 1.70 GHz
13184. 1.48 – 1.50 GHz
13185. 1.28 – 1.30 GHz
13186. How many simultaneous calls does each DECT system can support?
13187. 96
13188. 12
13189. 24
13190. 49
13191. How many simultaneous calls does a DECT radio transceiver can assess at any
given time?
13192. 120
13193. 240
13194. 480
13195. 960
13196. The AGC voltage of a radio receiver is always _______.
13197. Present before adjustments can be made
13198. DC, but may have either polarity positive DC
13199. Positive DC
13200. Negative
13201. What is a concentrator?
13202.
A system that improves the signal-to-noise ratio by compressing the
volume range of a signal.

13203.
A device that varies the characteristics of a carrier signal in accordance
with the waveform of a modulating signal which contains useful information
13204.
A switching system that lets a large number of telephone or data
processing subscribers use a lesser number of transmission lines or a narrow
bandwidth
13205.
Equipment in the central office.
13206. If you find that an SAW filter output is 6 dB down from the input of a receiver
during test, ______
13207.
This is normal.
13208.
The device if faulty
13209.
The receiver is improperly terminated
13210.
The filter is not resonating
13211. A triple conversion superheterodyne receiver, diode mixer stages are
13212.
Operated in the linear region
13213.
Operated in the nonlinear region
13214.
Operated as Class-A amplifiers
13215.
Operated as Class-B amplifiers
13216. What is a leased line?
13217.
A piece of wire used in a local area network in one building
13218.
A piece of wire connecting a telephone set to a PABX
13219.
A temporary connection of one computer to a mainframe via a modern and
a telephone line
13220.
A permanent circuit for a private use within a communication
network
13221. If two FM signals of different strengths are received on the same frequency
13222.
One steady heterodyne will appear in the AM output
13223.
Both will appear in the AF output
13224.
Only the stronger will appear in the AF output
13225.
Neither signal will be intelligence unless the weaker signal is at least 10
times
13226. Cellular mobile system was first operated in
13227.
1979
13228.
1981
13229.
1983
13230.
1985
13231. TACS is a cellular system with ______ channels.
13232.
666
13233.
1000
13234.
832
13235.
200
13236. Supervisory Audio Tone (SAT) has _______ frequency.
13237.
5960 Hz
13238.
6000 Hz
13239.
6040 Hz
13240.
1004 z
13241. What is the number of channels of a cellular system with an allocated spectrum of

25 MHz and with a channel of 30 kHz bandwidth?
13242.
833
13243.
240
13244.
1000
13245.
666
13246. GSSM uses what digital modulation technique?
13247.
QAM
13248.
GFSK
13249.
BPSK
13250.
GMSK
13251. What is the power output of Personal Communication System (PCS)?
13252.
10 mW
13253.
75 mW
13254.
150 mW
13255.
10 W
13256. RG-B8 cable has a loss of about ______ dB at cellular frequencies up to 15 ft.
length.
13257.
2
13258.
1
13259.
4
13260.
3
13261. The signals designed to keep the receivers and transmitters aligned.
13262.
Carrier frequencies
13263.
Pilot carrier signals
13264.
Synchronizing signals
13265.
Reference signals
13266. If the spacing of a two-wire open air transmission line is 12 inches and the
conductor diameter is 0.25 inch, the characteristic impedance is
13267.
547 Ω
13268.
357 Ω
13269.
273 Ω
13270.
300 Ω
13271. The impedance of the quarterwave transformer used to match a 600 Ω line to a
300 Ω load is
13272.
382 Ω
13273.
424 Ω
13274.
565 Ω
13275.
712 Ω
13276. When a line and a load are match the reflection coefficient is
13277.
Unity
13278.
Zero
13279.
Positive infinity
13280.
Negative infinity
13281. When line is terminated in an open circuit load, the reflection coefficient is
13282.
A. Unity
13283.
B. Zero

13284.
C. Positive infinity
13285.
D. Negative infinity
13286. A 300 ohms line is terminated in a resistance load of 200 ohms, the VSWR is
13287.
0.65
13288.
1.5
13289.
Unity
13290.
Zero
13291. If the reflection coefficient is 0.5, the standing wave ratio is
13292.
0.33
13293.
Unity
13294.
3
13295.
Zero
13296. To least the fault of the given line, a signal is fed to the line, 30 µs later the signal
returned. What is the distance of the fault?
13297.
9000 m
13298.
300 m
13299.
100 m
13300.
4500 m
13301.
The telephone set is powered by the central office on the ring side at
13302.
42 to 52 Vdc
13303.
– 42 to -52 Vdc
13304.
24 to 64 Vdc
13305.
– 24 to – 64 Vdc
13306. The telephone voice band frequency is from
13307.
300 to 4 kHz
13308.
400 to 3400 Hz
13309.
300 to 3400 Hz
13310.
400 to 4 kHz
13311. Which of the following wire is used to transmit the signal?
13312.
Black
13313.
Yellow
13314.
Red
13315.
Green
13316. The corresponding frequency for digit 7 in the touch tone telephone is
13317.
770 & 1477 Hz
13318.
852 & 1209 Hz
13319.
852 & 1336 Hz
13320.
770 & 1336 Hz
13321. The physical connection between the telephone set and the switching equipment
is called the
13322.
Trunk line
13323.
Link
13324.
Subscriber loop
13325.
Leased line
13326. What is the local loop of a telephone system?
13327.
It is a two-wire or four-wire communication circuit between the

customer’s premise and the central office
13328.
It is a group of wires connecting a telephone set to a modern
13329.
It is a four-wire circuit connecting a facsimile machine to a computer
13330.
It is a single piece of wire connecting the subscriber’s telephone set to
another set in an adjacent room.
13331. Which of the ff. equipment is used in long loop design?
13332.
Dial long lines
13333.
Voice repeater
13334.
Loop range extender
13335.
All of the above
13336. What is a two-wire circuit?
13337.
A circuit usually in the subscriber loop, between the telephone set and
the local central office.
13338.
A circuit having only two terminals, both terminals having the same
instantaneous voltage.
13339.
A circuit with one input terminal, one output terminal, and a common
ground.
13340.
A circuit consisting of two transmission lines.
13341. 1 mW is equal to
13342.
90 dBm
13343.
0 dBm
13344.
-30 dBm
13345.
120 dBm
13346. Which of the following responds to the request of a subscriber by sending a dial
tone?
13347.
Line finder
13348.
First selector
13349.
Connector
13350.
Line equipment
13351. The other name of Class 2 office in the North American Switching Plan.
13352.
Primary center
13353.
Section
13354.
Regional center
13355.
Toll points
13356. A cell in the cellular telephone system means
13357.
A power source
13358.
Small area
13359.
Large area
13360.
Service area
13361. What is the linking point between cell phone and regular telephone?
13362.
Base station
13363.
Control office
13364.
C.O.
13365.
MTSO
13366. What is the typical power output of a cellular phone?
13367.
5W

13368.
10 W
13369.
1W
13370.
3W
13371. When a single cell is divided into smaller cells that process is called
13372.
Cell splitting
13373.
Cell division
13374.
Reuse
13375.
Cell sharing
13376. The first cell shape is a square
13377.
Square
13378.
Circle
13379.
Rectangle
13380.
Triangle
13381. In order to provide 100% coverage without overlap, cellular telephone system can
use
13382.
Hexagon cell shape
13383.
Triangle
13384.
Rectangular
13385.
All of the above
13386. What is the beamwidth of the reflector of the receiving antenna in the base station
13387.
20 degrees
13388.
30 degrees
13389.
50 degrees
13390.
60 degrees
13391. A cellular phone operates on
13392.
Half duplex
13393.
Full duplex
13394.
Echoplex
13395.
Lincomplex
13396. Cellular phones transmit in the band from
13397.
825 to 845 MHz
13398.
835 to 855 MHz
13399.
825 to 855 MHz
13400.
825 to 865 MHz
13401. Cell phone receives in the band from
13402.
860 to 880 MHz
13403.
870 to 890 MHz
13404.
870 to 880 MHz
13405.
860 to 890 MHz
13406. What is the frequency separation between the transmit and the receive channels?
13407.
30 MHz
13408.
45 MHz
13409.
55 MHz
13410.
40 MHz
13411. For channel 1, transmit/receive frequency is
13412.
825.030/870.030 MHz

13413.
835.03/880.03 MHz
13414.
825.015/870.015 MHz
13415.
825.15/870.15 MHz
13416. The number of transmit/receive channels in the cellular system is
13417.
625
13418.
645
13419.
655
13420.
666
13421. The transmission range of cellular telephony is generally about
13422.
80 km
13423.
65 km
13424.
160 km
13425.
16 km
13426. One of the following is not an advantage of a cellular telephone system
13427.
Privacy
13428.
Large service area
13429.
No interference
13430.
Mobility
13431. When the message is transferred from one cell site transmitter to another cell site
transmitter as the caller crosses a boundary __________ process takes place.
13432.
Shifting
13433.
Hand off
13434.
Give off
13435.
Turn over
13436. What is the sensitivity of a cellular receiver?
13437.
20 dB
13438.
40 dB
13439.
50 dB
13440.
60 dB
13441. What is the frequency deviation of the cellular telephone system?
13442.
±15 kHz
13443.
±30 kHz
13444.
±12 kHz
13445.
±75 kHz
13446. Hailing channel is otherwise known as
13447.
Conversation channel
13448.
Calling channel
13449.
Signaling channel
13450.
Remote channel
13451. What is an Erlang?
13452.
It is a unit of magnetic field intensity measured around a conductor
13453.
It is the number of erroneous bits received per unit of time
13454.
It a unit of electrical energy radiated in space.
13455.
It is equal to the number of simultaneous calls originated during a
specific hourly period.
13456. All of the cell base stations are linked together by _______ which serves as the

central office and management node for the group.
13457.
MTS
13458.
IMTS
13459.
MSTO
13460.
MTSO
13461. Provides interface between the mobile telephone switching office and the mobile
units.
13462.
Database
13463.
Cell site
13464.
Terrestrial link
13465.
Radio transmitter
13466. A phone call over the cellular network actually requires
13467.
Simplex channels
13468.
Half duplex channels
13469.
Full duplex channels
13470.
Full/full duplex
13471. A method of expressing the amplitudes of complex non-periodic signals such as
speech.
13472.
Volume
13473.
Pitch
13474.
Frequency
13475.
Wavelength
13476. _______ is signal returned to the talker after one or more round trips between the
talker and the listener.
13477.
Singing
13478.
Echo
13479.
Jitter
13480.
Crosstalk
13481. ______ is a voice operated device that inserts a high loss in the opposite direction
of transmission of the talking party.
13482.
Hybrid
13483.
2-wire circuit
13484.
Echo suppressor
13485.
VNL
13486. _____ is picking up of the same station at two nearby points on the receiver dial.
13487.
Double spotting
13488.
Hot shot
13489.
Image frequency
13490.
Bail shot
13491. When one channel picks up the signal carried by another channel.
13492.
Echo
13493.
Crosstalk
13494.
Party line
13495.
Crosslink
13496. What type of connector arrangement wherein a customer may move to another
location and still retain the same telephone number.

13497.
TPL
13498.
Bridge
13499.
TPS
13500.
Party line
13501. It is an advantage of sidetone.
13502.
Transmission efficiency is increased
13503.
Speaker increase his voice resulting in a strengthened signal
13504.
No dissipation of energy in the balancing network
13505.
Assures the customer that the telephone is working
13506. Radio communications between points using a single share frequency.
13507.
Simplex
13508.
Full duplex
13509.
Half-duplex
13510.
Full/full duplex
13511. The transmission of information from multiple sources occurring on the same
facility but not as the same time.
13512.
FDM
13513.
TDM
13514.
WDM
13515.
CDM
13516. When human voice and music are transmitted, the type of communication
employed is known as
13517.
Raditechnology
13518.
Audio frequency
13519.
Wired audio
13520.
Radiotelephony
13521. Printed documents to be transmitted by fax are converted into baseband electric
signal by the process of
13522.
Copying
13523.
Scanning
13524.
Modulation
13525.
Light variation
13526. What is the most commonly used light sensor in a modern fax machine?
13527.
Phototube
13528.
Phototransistor
13529.
Liquid-crystal display
13530.
Charge couple device
13531. In FM fax, the frequencies for black and white are ______ repectively.
13532.
1500 and 2300 Hz
13533.
2300 and 1500 Hz
13534.
1300 and 2400 Hz
13535.
1070 and 1270 Hz
13536. Which resolution produces the best quality fax?
13537.
96 lines per inch
13538.
150 lines per inch
13539.
200 lines per inch

13540.
400 lines per inch
13541. Group 2 fax uses which modulation?
13542.
SSB
13543.
FSK
13544.
Vestigial sideband AM
13545.
PSK
13546. The most widely used fax standard is
13547.
Group 1
13548.
Group 2
13549.
Group 3
13550.
Group 4
13551. Group 3 fax uses which modulation?
13552.
QAM
13553.
ASK
13554.
PSK
13555.
GFSK
13556. Block calls held condition specified the held probability at a time period equal to
an average holding time.
13557.
Erlang B
13558.
Erlang C
13559.
Erlang D
13560.
Poisson
13561. What is an Echo?
13562.
A signal of the same amplitude but 180 degrees out of phase from the
original signal and mixed with the original signal at the transmitter to produce a
more intelligible output signal
13563.
A wave which has been reflected or otherwise returned with the
sufficient magnitude and delay for it to be perceptible in some manner as a
wave distinct from that directly transmitted.
13564.
The signal having a higher frequency than the original and transmitted
back to earth by a passive satellite.
13565.
A reflected signal.
13566. What is the system used by Personal Communication Network (PCN)?
13567.
TACS
13568.
Modified GSM
13569.
AMPS
13570.
CDMA
13571. Termination refers to
13572.
Cutting both ends of a conductor
13573.
Disconnecting a line from a transmitter
13574.
Looking back impedance of a line with no load
13575.
Load connected to the output end of a transmission line
13576. The multiple access used by Digital European Cordless Telephone (DECT)
13577.
CDMA
13578.
FDMA
13579.
TDMA

13580.
CDMA/FDMA
13581. Blocked calls delay condition specified delay probability
13582.
Erlang B
13583.
Erlang C
13584.
Erlang D
13585.
Poisson
13586. Status information provided by telephone signaling.
13587.
Busy tone, dial tone and ringing
13588.
Congestion and call charge data
13589.
All of the above
13590.
None of the above
13591. The modulation technique used by DECT.
13592.
GFSK
13593.
ASK
13594.
QAM
13595.
PSK
13596. What is a four-wire circuit?
13597.
Is used between serving central offices for long-distance connections,
with one pair being used for each direction of transmission.
13598.
Is a circuit with three output terminals and one input terminal
13599.
Is an oscillator that produces four different frequencies simultaneously
13600.
A circuit consisting of four transmission lines.
13601. Cellular CDMA system uses what modulation method?
13602.
GFSK
13603.
ASK
13604.
QAM
13605.
BPSK
13606. PABX means
13607.
Private All-purpose Broadcasting Exchange
13608.
Private Automatic Branch Exchange
13609.
Public Access Bi-directional Exchange
13610.
Public Automatic Branch Exchange
13611. What is the voted cellular digital standard at TIA?
13612.
Digital AMPS
13613.
GSM
13614.
CDMA
13615.
TACS
13616. What is the number of channels for Band A and for Band B in Digital AMPS
13617.
832
13618.
416
13619.
666
13620.
888
13621. The mobile-to-base frequency assignment for GSM system is
13622.
890-915 MHz
13623.
935-960 MHz
13624.
870-890 MHz

13625.
825-845 MHz
13626. The range (in miles) of a cellular CDMA system.
13627.
13
13628.
30
13629.
45
13630.
20
13631. In a cellular system, ________ is used to measure the spectrum efficiency.
13632.
Radio efficiency
13633.
Diversity
13634.
Frequency reuse
13635.
Radio capacity
13636. Which of the following echo is completely out of control?
13637.
Worst echo
13638.
Reverberation
13639.
Singing
13640.
Feedback
13641. Which of the following devices increase the battery voltage on a loop and extends
its signaling range?
13642.
Loop extender
13643.
VF repeater
13644.
VF amplifier
13645.
All of these
13646. Under ordinary circumstances, the CCITT recommends that the number of
circuits in tandem must not exceed
13647.
9
13648.
10
13649.
11
13650.
12
13651. What is the system capacity of AMPS?
13652.
30,000
13653.
60,000
13654.
100,000
13655.
120,000
13656. NAM means
13657.
Non Alternable Memory
13658.
Numeric Allocation Module
13659.
Numeric Assignment Module
13660.
Numeric Access Module
13661. Modulation – Chapter 3
13662. ______ is the maximum sideband suppression value using filter system.
13663.
50 dB
13664.
60 dB
13665.
40 dB
13666.
30 dB
13667. _______ determines the number of sideband components in FM.
carrier frequency

modulation frequency
modulation index
deviation ratio
13668. One of the following transmits only one sideband.
H3E
R3E
A3E
B8E
13669. What produces the sidebands on FM?
signal amplitude
carrier harmonics
baseband frequency
broadband frequency
13670. Which test instrument displays the carrier and the sidebands amplitude with frequency to
frequency?
oscilloscope
spectrum analyzer
frequency analyzer
amplitude analyzer
13671. Mixer is also known as a ________.
modulator
suppressor
converter
beater
13672. Which one of the following emission transmits the lower sideband and half of the upper
sideband?
A5C
J3E
A3J
A3H
13673. An FM receives signal ______.
vary in amplitude with modulation
vary in frequency with modulation
vary in frequency and amplitude with wideband modulation
is not immune to noise
13674. The process of impressing intelligence on the carrier is called
modulation
detection
mixing
impression
13675. ______ is an electronic instrument used to show both the carrier and the sidebands of a
modulated signal in the frequency domain.
spectrum analyzer
oscilloscope
digital counter
frequency counter

13676. What part of the carrier is varied by the intelligence during modulation in an AM system?
phase
frequency
amplitude
both a and c
13677. The difference between the RF carrier and the modulating signal frequencies is called the
USB
LSB
Sideband
Carrier frequency
13678. What stage in a radio transmitter isolates the oscillator from the load?
Oscillator
Buffer
Separator
Mixer
13679. The frequency of the unmodulated carrier in FM system is
modulating frequency
center frequency
carrier frequency
deviation frequency
13680. The ratio of maximum deviation to the maximum modulating frequency is called
carrier swing
deviation ratio
modulation factor
modulation index
13681. A carrier signal has
constant amplitude
a frequency of 20 kHz and above
a varying amplitude
the information content
13682. The modulated peak value of a signal is 125 V and the unmodulated carrier value is 85 V.
What is the modulation index?
0.47
0.68
0.32
1.47
13683. An 891 kHz carrier having an amplitude of 80 V is modulated by a 4.5 kHz audio signal
having an amplitude of 45 V. The modulation factor is
0.56
0.65
1.78
1.25
13684. What is the modulation index of an FM signal having a carrier swing of 75 kHz when the
modulating signal has frequency of 3 kHz?
25
12.5

0.04
0.08
13685. In a FM system, if modulation index is doubled by having the modulating frequency,
what will be the effect on the maximum deviation?
No effect
Maximum deviation doubles
Decreases by ½
Increases by ¼
13686. Which of the following is considered as an indirect method of generating FM?
Reactance modulator
Balanced modulator
Varactor diode modulator
Armstrong system
13687. To generate an SSB or DSB signal one must use a circuit known as
filter modulator
ring modulator
balanced modulator
reactance modulator
13688. Which is the first radio receiver?
TRF receiver
Superheterodyne receiver
Crystal radio receiver
Heterodyne receiver
13689. An interfering signal with a frequency equal to the received signal plus twice the IF is
called
image frequency
center frequency
rest frequency
interference frequency
13690. Double sideband full carrier emission type
13691.
A3J
13692.
H3E
13693.
R3A
13694.
A3E
13695. Single sideband reduced carrier emission type
H3E
R3E
J3E
B8E
13696. A single sideband suppressed carrier emission type.
H3e
R3E
J3E
B8E
13697. Independent sideband emission type
H3E

R3E
J3E
B8E
13698. Vestigial sideband emission type
C3F
J3E
R3E
B8E
13699. Single sideband full carrier emission type.
R3E
H3E
J3E
B8E
13700. Phase modulation emission type.
F3E
F3C
F3F
G3E
13701. Which one is not an advantage of SSB over AM?
Power saving
Requires half the bandwidth
Wider area of reception
Better fidelity
13702. The advantage of a high level modulated AM transmitter is
Less audio power required
Better fidelity
Higher value of operating power
Less distortion
13703. The advantage of a low-level modulated AM transmitter is
Less audio power required
Better fidelity
Higher value of operating power
Less distortion
13704. _____ is the bad effect caused by overmodulation in AM transmission.
Increase in noise
Deviation in the operating frequency
Interface to other radio services
Decrease in the output power
13705. Which characteristic of a radio receiver refers to its ability to reject an unwanted signal?
Sensitivity
Selectivity
Fidelity
Quality
13706. What type of emission is frequency modulation?
F3E
G3E

A3E
B3E
13707. AM transmission power increases with ________.
Frequency
Source
Load
Modulation
13708. _______ locks the FM receiver to a stronger signal.
Hall effect
Capture effect
Image frequency
Homing
13709. What is the highest percentage of modulation for AM?
50%
75%
100%
80%
13710. In FM, the Carson’s Rule states that the bandwidth is equal to twice the sum of the
modulating frequency and ______.
Carrier signal
Modulating signal
Frequency deviation
Image frequency
13711. What is the carrier swing of an FM transmitter when modified by 75%?
53.2 kHz
48 kHz
56.25 kHz
112.5 kHz
13712. The modulation system inherently more resistant to noise
Single sideband suppressed carrier
Frequency modulation
Pulse-position modulation
Amplitude shift keying
13713. Subcarriers that are arranged so that the channels occupying adjacent frequency bands
with some frequency space between them is known as
Guard bands
AM bands
Band gap
Void band
13714. Modulation of an RF amplifier carrier results in
Multiple channels
Smaller antennas
Directional propagation
All of the above
13715. A process which occurs in the transmitter
Mixing

Modulation
Heterodyning
Demodulation
13716. A process which occurs in the receiver
Beating
Modulation
Mixing
Demodulation
13717. One part of the transmitter that protects the crystal oscillator from “pulling”.
Buffer amplifier
Modulator
Power amplifier
Antenna coupler
13718. What aspect of the carrier is changed by modulation?
Frequency
Phase
Amplitude
Depends on the type of modulation
13719. The amplitude of a sine wave which is modulated by a musical program will
Be complex
Contain fundamental frequencies
Contain harmonic frequencies
All of the above
13720. What will be the result of the gain level being too high for signals entering the
modulator?
Receiver noise
Excessive volume of receiver output
Oscillator disturbances
Distortion and splatter
13721. Amplitude modulation causes the amount of transmitter power to
Increase
Decrease
Remain the same
Double
13722. When a carrier is modulated 100%, the total power increases by what percentage over
that of the carrier alone?
25%
50%
75%
100%
13723. When the amplitude of the modulating voltage is increased for AM, the antenna current
will
Increase
Decrease
Remain constant
Decrease exponentially

13724. An increase in transmitter power from 25W to 30W will cause the antenna current to
increase from 700mA to
800 mA
750 mA
767 mA
840 mA
13725. A second modulating tone having the same amplitude but a different frequency is added
to the first at the input to the modulator. The modulation index will be increased by a factor
of
√3

√2
2
3
13726. A 1000 kHz carrier is modulated by a 2500Hz tone. One frequency component of the
modulated signal is
1200 Hz
5000 Hz
1002.5 kHz
2500 Hz
13727. A 1200 kHz carrier is amplitude-modulated by two tones of 500 Hz and 700 Hz. Which
one is a frequency component of the modulated wave?
1195 kHz
1199.3 kHz
1199.7 kHz
1205 kHz
13728. Identify a modulation method, or methods in use for a common-emitter configuration
Base modulation
Emitter modulation
Collector modulation
Both A and C
13729. The RF signal injected into a balanced modulator is 10MHz and the modulating
frequency is 1 kHz. Which frequency, or frequencies, will not appear in the output?
9.999 MHz
10 MHz
10.0001 MHz
Both A and B
13730. Unwanted sidebands in SSB equipment can be suppressed by one or more of the
following methods.
Phasing method
Filter method
Decoder method
Both A and B
13731. Envelope detection is concerned with the process of
Mixing
Heterodyning

Modulation
Rectification
13732. Diagonal clipping in envelope detection will result in
Distortion
Phase reversal
Reduced sensitivity
Amplitude damage
13733. Product detection requires the process of
Rectification
Heterodyning
Decoding
Phase shifting
13734. A sine wave which is coherent with carrier has identical
Amplitude
Frequency
Phase angle
Both B and C
13735. Frequency modulation and phase modulation are collectively referred to as
Stereo
Angle modulation
High fidelity modulation
FCC modulation
13736. In FM, the change in carrier frequency is proportional to what attribute of the modulating
signal?
Angle
Frequency
Amplitude
Tone
13737. A louder sound, when generating the modulating waveform for FM, will cause a greater
Carrier amplitude
Angle amplitude
Distortion at the receiver
Frequency deviation
13738. If a positive change in modulation signal level of 200 mW will cause a positive frequency
deviation of 10 kHz, what will be the frequency deviation for a negative change of 10 mV in
the level of the modulating signals?
0
-5 kHz
+5 kHz
+0 kHz
13739. A particular 15 kHz modulation tone results in a peak frequency deviation of 75 kHz.
What is the modulation index?
5
15
75
3

13740. A 15 kHz sine wave frequency modulates an 88 MHz carrier. A sideband frequency will
be found at
87.970 MHz
87.985 MHz
88.015 MHz
All of these
13741. A device whose capacitance is deliberately made to be a function of the applied voltage
Varactor diode
UJT
SAW
Variable capacitor
13742. A reactance modulator is one method of obtaining
Indirect FM
Direct FM
Demodulation
Low frequency filtering
13743. A device, now available in IC form, is useful for direct FM and as one element in the
phse-locked loop.
AFC
AGC
VCO
LPF
13744. _____ is a frequency change process, whereby the phase deviation and frequency
deviation are multiplied by some fixed constant.
Translation
Multiplication
Division
Addition
13745. A circuit that has the function of demodulating the frequency-modulated signal.
AFC
Envelope detector
Decoder
Foster-Seeley discriminator
13746. The ratio detector is superior to the slope detector because
It is less sensitive to phase modulation
It is less sensitive to noise spikes
It is less sensitive to interference causing AM
Both B and C
13747. One implementation of a pulse averaging discriminator is
A free-running multivibrator
A crystal-controlled oscillator
A quartz crystal filter
A triggered multivibrator
13748. A 10% increase in the frequency of a constant-width pulse train should cause what
change in its average value?
-10%

-1%
+1%
+10%
13749. Two different signals can be coherent if they
Have the same amplitude
Are both sine waves of different frequencies
Originate in the same physical equipment simultaneously
Have the same frequency
13750. A quadrature detector requires that
Four gates bee provided
The inputs are coherent
The inputs are incoherent
The inputs are identical
13751. In a phase-locked loop, the VCO is the abbreviation for
Variable coherent output
VHF communication oscillator
Voltage-controlled oscillator
Vien-count oscillator (neutralized)
13752. Identify an advantage, or advantages of a properly designed FM system.
Relative immunity to atmospheric noise (lightning)
Reduced bandwidth required
No noise of any kind
The noise figure is inversely proportional to the modulation index
13753. The output of a balanced modulator
LSB and USB
LSB
USB
Carrier
13754. If the modulation index of an AM wave is changed from 0 to 1, the transmitted power is
Unchanged
Halved
Doubled
Increased by 50%
13755. Which of the following is not a baseband signal of modulation?
Audio signal
Video signal
RF carrier
Binary coded pulses
13756. If the unmodulated level peak carrier amplitude is doubled in an AM signal, the perfect
modulation is ________.
20
50
100
200
13757. Balanced modulator circuit when inserted in the equivalent suppresses the ___________
Carrier

Upper sideband
Lower sideband
Baseband signal
13758. The carrier of a 100% modulated AM wave is suppressed, the percentage power saving is
__.
100%
50%
83%
66.66%
13759. If the modulation index if an AM wave is doubled, the antenna current is also doubled,
the AM system being used is
H3E
J3E
C3F
A3E
13760. 100% modulation in AM means a corresponding increase in total power by _______.
100%
50%
75%
25%
13761. A single-tone amplitude modulated wave has _______.
2 components
3 components
4 components
2n + 1 components
13762. A carrier signal has ________.
Constant peak amplitude
Frequency range of 20 – 20,000 Hz
A varying amplitude
The information
13763. The modulating system is _________ if the modulating frequency is doubled, the
modulation index is halved, and the modulating voltage remains constant.
Amplitude modulation
Phase modulation
Frequency modulation
Pulse modulation
13764. What is the modulation index of an FM signal if its modulating frequency is doubled?
No effect
Twice the original index
Four times the original index
One-half the original index
13765. An AM transmitter is rated 1000 W at 100% modulation. How much power required for
the carrier?
1000 W
666.6 W
333.3 W

866.6 W
13766. Standard way of designating AM
A3E
B3E
AHE
C3F
13767. _____ is the circuit used to detect frequency modulated signal.
Discriminator
Modulator
Modem
Detector
13768. _____ is an information signal that is sent directly without modulating any carrier.
C-band
Q-band
Baseband
Broadband
13769. Both frequency and phase modulation utilize ______ modulation.
Digital
Phase
Amplitude
Angle
13770. It is the width of frequencies within the spectrum occupied by a signal and used by the
signal for conveying information.
Band
Bandwidth
Electronic spectrum
Frequency band
13771. Which transmit only one sideband?
H3E
C3F
A3E
B8E
13772. ______ is kind of modulation in which the modulated wave is always present.
Carrier modulation
Continuous modulation
Log-periodic modulation
Square-wave modulation
13773. A type of modulation in which no signal is present between pulses.
Pulse modulation
FSK
QAM
PAM
13774. What describes the amount of amplitude change present in an AM waveform?
Percent modulation
Modulation constant
Envelope of modulation

Coefficient of modulation
13775. _______ is a form of amplitude distortion introduced when the positive and negative
alternations in the AM modulated signals are not equal.
Envelope distortion
Spurious emission
Carrier shift
Johnson noise
13776. What is the advantage of phase modulation over direct FM frequency modulation?
Multipliers can be used
The deviation is smaller
Simplicity and practicality
The oscillator is crystal-controlled
13777. If the spectrum is shifted in frequency with no other changes, this is known as
Frequency multiplication
Sideband movement
Baseband reorientation
Frequency translation
13778. A device which is capable of causing frequency translation
High-Q tank circuit
Balanced modulator
Low-Q tank circuit
IF strip
13779. If the frequency of each component in a signal spectrum is increased by the same fixed
amount, this known as
Modulation
Frequency translation
Up conversion
Both B and C
13780. A particular amplifier is designed to be a frequency doubler. If the input signal frequency
is 15.4 MHz, a circuit in the output will be tuned to
7.7 MHz
15.4 MHz
30.8 MHz
61.6 MHz
13781. A sine wave of 293 MHz is phase-modulated to achieve a maximum phase deviation of
0.2 radian. After passing through a frequency tripler, the maximum phase deviation will be
0.2 radian
0.3 radian
0.4 radian
0.6 radian
13782. Any device to be used as a frequency multiplier must be
Active
Passive
Linear
Nonlinear
13783. A particular amplifier circuit used for frequency doubling.

Push-push
Push-pull
Pull-push
Pull-pull
13784. Frequency division is useful in the implementation of a
AM demodulator
Frequency synthesizer
AGC circuit
FM demodulator
13785. Frequency division by 12 will require how many flip-flops in the counter?
3
4
6
12
13786. Identify an electronic device, not specifically designed for the purpose, which can be
used as a phase detector.
Wien bridge
Colpitts oscillator
Balanced modulator
Butterworth filter
13787. A particular frequency synthesizer contains only a single crystal. What words describe
this synthesizer?
Crystal modulated
Inexact
Indirect
Deficient
13788. A recognizable feature of a CW transmitter is
Keyed transmitter
Power amplification
Frequency generation
All of these
13789. The term “pulling” refers to
The change of the crystal oscillator frequency by loading
One half-cycle operation of a push-pull amplifier
Loading on the transmitter caused by the antenna connection
Reduction of the power supply terminal voltage as the transmitter is keyed.
13790. When frequency modulation is achieved by initial phase modulation, this is called
Angular modulation
Direct FM
Indirect FM
Indirect synthesis
13791. A disadvantage of direct FM is the need for
AGC
AFC
A frequency synthesizer
Phase modulation

13792. Direct FM can be achieved by
A reactance tube modulator
A varactor diode
And AGC circuit
Both A and B
13793. A receiver in which all RF amplifier stages require manual tuning to the desired RF is
called
Superheterodyne
Autodyne
TRF
AFC
13794. Why is it often necessary to precede the demodulator by amplifier stages in a receiver?
To improve fidelity
To reduce receiver noise
To eliminate image response
Weak antenna signals
13795. A serious disadvantage of the TRF receiver.
Bandwidth variations over the tuning range
The weight and cost
The requirements for a closely regulated power supply
The requirements for a half-wave antenna
13796. Identify which is not a part of a superheterodyne receiver.
Local oscillator
Modulator
IF amplifier
Demodulator
13797. Which major element will not be found in every superheterodyne receiver?
R–F amplifier
Mixer
Local oscillator
IF amplifier
13798. Which major element of a superheterodyne receiver must be nonlinear?
R-F amplifier
Mixer
Local oscillator
IF amplifier
13799. The change of the modulated carrier frequency from the original RF to the IF of the
superheterodyne receiver is known as
Frequency multiplication
Frequency allocation
Frequency substitution
Frequency translation
13800. The key to achieving receiver sensitivity is the reduction of
Image response
Mixer harmonic products
Spurious frequency response

Internal noise
13801. Which of the following receiver design objectives is not impossible?
Elimination of galactic noise
Elimination of atmospheric noise
Elimination of man-made noise
Reduction of receiver internal noise
13802. In comparing the S/N ratio for the input to the receiver with the S/N ratio for the output,
the latter is
Smaller
The same
Greater
Infinite
13803. The characteristic of a receiver that specifies the self-generated noise.
Noise immunity
Noise factor
Noise figure
Noise margin
13804. An FM receiver with an I-F of 10.7 MHz is tuned to 98.7 MHz. What is the numerical
value of the image frequency?
77.3 MHz
88.0 MHz
109.4 MHz
120.1 MHz
13805. A source of RF interference exists at 109.9 MHz. For which frequency in the FM
broadcast band will this be the image frequency?
21.4 MHz
88.5 MHz
99.2 MHz
110.7 MHz
13806. The ratio of the superheterodyne receiver response at the desired carrier frequency to that
at the image frequency is called
The sensitivity
The selectivity
The image frequency
The image rejection ratio
13807. The core of an IF transformer usually contains
Teflon
Computer nylon
Powdered iron
Laminated steel
13808. Shape factor is a measure of
Bandwidth
Skirt steepness
Coupling coefficient
Critical coupling
13809. _______ is the function which tends to maintain the sound volume level of a voice

receiver nearly constant for a large signal strength range.
Squelch
Muting
AGC
AFC
13810. The function which tends to silence the receiver in the absence of transmitted carrier.
Squelch
Muting
AGC
AFC
13811. What device is incorporated in a communications receiver to reduce impulse noise?
Front-end processor
Squelch circuit
AGC
Noise blanker
13812. What type of signal in which a receiver selectivity of 2.4 kHz in the I-F circuitry is
optimum?
FM voice
Double-sideband AM voice
FSK data
SBB voice
13813. If the input to a detector stage is an amplitude-modulated (A3E) IF signal then the output
from the stage is
A lower frequency carrier
The audio voice information
A Morse-code signal
The upper or lower set of sidebands
13814. In a capacitive type, reactance-tube modulator connected across an oscillator tuned
circuit, a more negative voltage on the grid of the reactance tube will cause
An increase of the oscillator frequency
An decrease of oscillator frequency
An increase of the reactance-tube capacitance
An increase of the reactance tube ac plate current
13815. The limiting condition for sensitivity in a communications receiver is
The noise floor of the receiver
Power supply output ripple
The two-tone intermodulation distortion
The input impedance to the detector
13816. When a communications receiver is tuned to a strong signal, the AGC bias is measured
and found to be zero. The fault cannot be caused by a/an
Defective IF stage
Defective local oscillator
Defective RF stage
Open circuit in the AGC’s filter capacitor
13817. The term used to refer to the condition where the signals from a very strong station are
superimposed on other signals being received

Cross-modulation interference
Intermodulation interference
Receiver quieting
Capture effect
13818. The limiter stage of an FM receiver
Behaves as a low-pass filter
Limits the amplitude of the IF signal to the required level
Behaves as a high-pass filter
Behaves as a bandstop filter
13819. Motorboating (low-frequency oscillations) in an amplifier can be stopped by
Grounding the screen grid
Connecting a capacitor between the B+ and lead ground
By passing the screen grid resistor with a 0.1 µF capacitor
Grounding the plate
13820. An effect in which, the modulation of an unwanted signal is transferred to the desired
carrier.
Crossmodulation
Intermodulation
Modulation mixing
Image-channel interference
13821. Leads should be kept as short as possible in radio circuit so that
Skin effect is reduced
There is less hysteresis effect
There is less dielectric loss
Stray coupling is minimized
13822. The number of voice transmissions that can be packed into a given frequency band for
amplitude-compandored single-sideband systems over conventional FM-phone systems.
2
18
16
4
13823. Neutralization of an RF amplifier stage can be necessary in order to
Increase the amplifier’s gain
Prevent the generation of spurious oscillations
Reduce the amplifier’s gain
Reduce the level of the output harmonics
13824. The ability of a communications receiver to perform well in the presence of strong
signals outside the band of interest is indicated by what parameter?
Blocking dynamic range
Noise figure
Signal-to-noise ratio
Audio output
13825. Stages that are common to both AM and FM receivers
Tuner, local oscillator, detector, AF amplifier
RF amplifier, mixer, IF amplifier, AF amplifier
Local oscillator, RF amplifier, frequency discriminator, detector

Tuner, IF amplifier, detector, AF amp
13826. Occurs during CW reception if too narrow a filter bandwidth is used in the IF stage of a
receiver
Filter ringing
Undesired signals will reach the audio stage
Output-offset overshoot
Cross-modulation distortion
13827. What stage mainly determines a communication receiver’s sensitivity?
IF amplifier
Mixer stage
Detector stage
RF amplifier
13828. What is the main advantage of FM over AM?
Better signal-to-noise-ratio
Narrower bandwidth
Greater propagation range
Total freedom from adjacent-channel interference
13829. An amplitude modulation created in an amplifier before the final RF stage.
Low-level modulation
High-level modulation
Direct modulation
Indirect modulation
13830. Receiver desensitizing can be reduced by
Increasing the transmitter audio gain
Decreasing the receiver squelch gain
Increasing the receiver bandwidth
Ensuring good RF shielding between the transmitter
13831. In a narrow-band FM system, the deviation ratio is commonly one and the highest audio
frequency is generally limited to
300 Hz
10,000 Hz
3,000 Hz
7,500 Hz
13832. A type of emission is produced when an amplitude modulated transmitter is modulated by
a facsimile signal
A3F
F3F
A3C
F3C
13833. Where is the noise generated which primarily determines the signal to noise ratio in a
VHF (150 MHz) marine band receiver?
In the detector
In the atmosphere
In the ionosphere
In the receiver front end
13834. Cross-modulation in a receiver can be reduced by

Installing a filter at the receiver
Using a filter at the receiver
Increasing the receiver’s RF gain while decreasing the AF
Adjusting the pass-band tuning
13835. What is the emission designation for FM telephony?
F3E
G3E
J3E
H3E
13836. What is the cause of receiver desensitizing?
The presence of a strong signal on a nearby frequency
Audio gain adjusted too low
Squelch gain adjusted too high
Squelch gain adjusted too low
13837. In a phase-modulated signal (indirect FM), the frequency deviation is directly
proportional to the
Carrier amplitude only
Amplitude of the modulating tone and frequency of the carrier
Carrier frequency only
Modulating signal amplitude only
13838. An RF stage precedes the mixer stage in a superhet receiver. One advantage of including
this RF stage is
Better selectivity
Better rejection ratio
Greater sensitivity
Improved signal-to-noise-ratio
13839. Two factors that determine the sensitivity of a receiver.
Dynamic range and third-order intercept
Cost and availability
Bandwidth and noise figure
Intermodulation distortion and dynamic range
13840. What is an undesirable effect of using too-wide a filter bandwidth in the IF section of a
receiver?
Undesired signals will reach the audio stage
Output-offset overshoot
Thermal-noise distortion
Filter ringing
13841. A system containing a limiter stage, a discriminator, and a de-emphasis circuit?
Direct FM transmitter
Indirect FM transmitter
Single sideband AM receiver
FM receiver
13842. The limiter stage of an FM receiver
Prevents any amplitude modulation of the IF signal
Limits the amount of frequency deviation in the IF signal
Limits the overall bandwidth of the IF stages

Corrects any deviation in carrier frequency
13843. High selectivity occurs when the degree of coupling between a receiver’s RF stages is
Tight
Loose
Critical
Adjusted for maximum power transfer
13844. A carrier is phase modulated by a test tone. If the amplitude and the frequency of the tone
are both doubled, the amount of the deviation is
Doubled
Unchanged
Halved
Multiplied by four
13845. The degree of selectivity desirable in the IF circuitry of a single-sideband receiver.
1 kHz
2.4 kHz
4.2 kHz
4.8 kHz
13846. The component most apt to break down in the radio circuit is the
Crystal
Resistor
Transformer
Diode
13847. The base in an RF amplifier is grounded in order to
Avoid the requirement of neutralizing the stage
Raise the input impedance
Lower the output impedance
Obtain maximum power output
13848. The AM detector performs two basic functions in the receiver.
Rectifies and filters
Amplifiers and filters
Buffer and amplifier
Buffer and detector
13849. A varactor diode can be used in a/an
Direct FM modulator circuit
AFC circuit in a direct FM transmitter
Phase-modulator circuit
All of these
13850. Receiver interference is not reduced by including a/an
Crystal filter
Insulating enclosures around the receiver
Wave trap
RF stage
13851. What is the emission C3F?
RTTY
SSB
Television

Modulated CW
13852. What is the approximate dc input power to a class AB RF power amplifier stage in an
unmodulated carrier transmitter when the PEP output is 500 W?
Approximately 1000 W
Approximately 800 W
Approximately 250 W
Approximately 600 W
13853. Which of the following stages in an FM receiver is responsible for drastically reducing
the effect of static noise during the reception of a signal
De-emphasis circuit
Mixer stage
Squelch circuit
Limiter stage
13854. The letters “SSSC” stands for
Single sideband, single carrier
Suppressed sideband, single channel
Suppressed sideband, single carrier
Single sideband, suppressed carrier
13855. For many types of voices, what is the ratio of PEP-to-average power during a modulation
peak in a single-sideband phone signal?
Approximately 1.0 to 1
Approximately 25 to 1
Approximately 100 to 1
Approximately 2.5 to 1
13856. In most mixers, the oscillator frequency is ______ than the carrier frequency of the input
signal.
Higher
Lower
The same
10 kHz above
13857. Features of a transmitter’s buffer stage include
High stage
Harmonic generation
Improvement in frequency stability of the oscillator
Low input impedance
13858. Type of emission produced when an amplitude modulated transmitter is modulated by a
television signal
F3F
A3C
F3C
A3F
13859. A network is
A network consisting entirely of four inductors or four capacitors
A power incidence network
An antenna matching network that is isolated from ground
A network consisting of one inductor and two capacitors

13860. How is G3E FM-phone signals produced?
A network consisting modulator on the audio amplifier
With a reactance modulator on the final amplifier
With a reactance modulator on the oscillator
With a balanced modulator on the oscillator
13861. A way of eliminating auto interference to radio reception
Installing resistive spark plugs
Installing capacitive spark plugs
Installing resistors in series with the spark plugs
Installing two copper-braid ground strips
13862. The carrier in an AM transmitter is the
Transmitter’s output signal when the modulation is present
Transmitter’s output signal when the modulation is zero
Output signal from the crystal oscillator
RMS value of the AM signal
13863. What stage feeds the discriminator of an FM receiver?
Local oscillator
Mixer stage
Final IF amplifier, which also acts as a limiter stage
Buffer
13864. In an FM receiver, the stage that has the IF signal is input and the audio signal output.
Limiter
Audio amplifier
IF amplifier
Discriminator
13865. What is capture effect?
All signals on a frequency are demodulated by an FM receiver
The loudest signal received is the only demodulated signal
All signals on a frequency are demodulated by an AM receiver
The weakest signal received is the only demodulated signal
13866. A double-sideband phone signal can be generated by
Feeding a phase-modulated signal into a low-pass filter
Modulating the plate voltage of a class-C amplifier
Using a balanced modulator followed by a filter
Detuning a Hartley oscillator
13867. Pre-emphasis is used in FM transmitters to improve the signal-to-noise ratio of
High modulating frequencies
Low modulating frequencies
All modulating frequencies
Frequencies carrier
13868. The result of cross-modulation is that
The modulation of an unwanted signal is heard on the desired signal
A decrease in modulation level of transmitted signals
Of receiver quieting
Of inverting sidebands in the final stage of the amplifier
13869. Which of the following contains de-emphasis circuit?

FM transmitter
FM receiver
VHF transmitter
VHF receiver
13870. What is emission F3F?
AM
Facsimile
Television
RTTY
13871. What type of emission is produced when a frequency modulated transmitter is modulated
by a facsimile signal?
F3C
A3C
F3F
A3F
13872. Two AM transmitting antennas are close together. As a result the two modulated signals
are mixed in the final RF stage of both transmitters. What is the resultant effect on other
station?
Harmonic interference
Intermodulation interference
Spurious interference
Crossmodulation interference
13873. The term used to refer to the reduction of receiver gain caused by the signal of a nearby
station transmitter in the same frequency band?
Quieting
Cross-modulation interference
Squelch gain rollback
Desensitizing
13874. What is the bandwidth occupied by the carrier, both sidebands and harmonics?
Authorized bandwidth
Bandwidth of emission and occupied bandwidth
Operating bandwidth
All of these
13875. A class-C RF amplifier is collector amplitude modulated and its average dc level
collector current does not change. This means
A normal condition
Excessive drive to the base
Insufficient drive to the base
Insufficient audio modulation
13876. What determines the percentage modulation of an FM transmitter?
Amplitude of the carrier
Modulating frequency
Carrier frequency
Amplitude of the modulating signal
13877. Deviation ratio of an FM transmitter is the ratio of the
Maximum frequency swing to the highest modulating frequency

Operating frequency of the assigned frequency
Frequency swing to the modulating frequency
Highest modulating frequency to the minimum frequency
13878. The main purpose of the beat frequency oscillator (BFO) is to generate
A 1 kHz not for Morse reception
Aid in the reception of weak voice-modulated signals
An output, whose frequency differs from the IF by 1 kHz
A signal, whose frequency is the same as intermediate frequency
13879. Normally, a linear class BRF power amplifier operates with a bias approximately equal to
Twice cut-off
Ten times cut-off value
50% of cut-off value
Projected cut-off
13880. The purpose why an RF amplifier is operated under linear class-B conditions (as opposed
to class-C) is to
Generate only even harmonics
Generate only odd harmonics
Increase the efficiency
Amplify of an AM signal
13881. The term used to refer to the condition where the signal from a very strong station are
superimposed on other signal being received.
Cross-modulation interference
Intermodulation distoriotion
Receiver quieting
Capture effect
13882. _________ is the amplitude of the maximum negative excursion of a signal as viewed on
an oscilloscope.
Peak-to-peak voltage
Inverse peak positive voltage
RMS voltage
Peak negative voltage
13883. The type of emission that suffer most from selective fading.
CW and SSB
SSB and TV
FM and double sideband AM
SSTV and CW
13884. In an FM-phone signal, ________ is the ratio between the actual frequency deviation to
the maximum frequency deviation.
FM compressibility
Modulating index
Percentage of modulation
Quieting index
13885. _______ is used to refer to the reception blockage of one FM-phone signal by another
FM-phone signal.
Capture effect
Desensitization

Cross-modulation interference
Frequency discrimination
13886. A receiver selectivity of 10 kHz in the IF circuitry is optimum for what type of singals?
SSB voice
Facsimile
FM
Double-sideband AM
13887. If the envelope of modulation is constant in amplitude this means
Zero beat
Under-modulation
Zero-modulation
Over-modulation
13888. What is the approximate bandwidth of an FM with a modulation factor of 12.5 and a
modulating frequency of 10 kHz?
20 kHz
270 kHz
250 kHz
45 kHz
13889. Amplitude modulation is the same as
Linear mixing
Analog multiplication
Signal summation
Multiplexing
13890. The negative half of the AM wave is supplied by a/an _______ on a diode modulator.
The tuned circuit
Transformer
Capacitor
Inductor
13891. One of the following can produce AM.
Having the carrier vary a resistance
Having the modulating signal vary a capacitance
Varying the carrier frequency
Varying the gain of an amplifier
13892. Amplitude modulators that vary the carrier amplitude with the modulating signal by
passing it through an attenuator network is the principle of
Rectification
Amplification
Variable resistance
Absorption
13893. Which component is used to produce AM at very high frequencies?
Varactor diode
Thermistor
Cavity resonator
PIN diode
13894. A collector modulator has a supply voltage of 48 V. What is the peak-to-peak amplitude
of the modulating signal for 100 percent modulation?

24 V
48 V
96 V
120 V
13895. What circuit recovers the original modulating information from an AM signal?
Modulator
Demodulator
Mixer
Crystal set
13896. What is the most commonly used amplitude demodulator?
Envelope detector
Balanced modulator
Mixer
Crystal set
13897. What circuit generates the upper and lower sidebands and suppresses the carrier?
Amplitude modulator
Diode detector
Class C amplifier
Balanced modulator
13898. _________ is a widely used balanced modulator.
Diode bridge circuit
Full-wave bridge rectifier
Lattice modulator
Balanced bridge modulator
13899. In a diode ring modulator, the diodes act like
Variable resistors
Switches
Rectifiers
Variable capacitors
13900. The output of a balanced modulator is
AM
FM
SSB
DSB
13901. The principal circuit in the popular 1496/1596 IC balanced modulator is a
Differential amplifier
Rectifier
Bridge
Constant current source
13902. The most commonly used filter in SSB generators uses
LC networks
Mechanical resonators
Crystals
RC networks and op amps
13903. In the phasing method of SSB generation, one sideband is canceled out due to
Phase shifting

Sharp selectivity
Carrier suppression
Phase inversion
13904. A balanced modulator used to demodulate a SSB signal is call a/an
Transponder
Product detector
Converter
Remodulator
13905. Frequency translation is done with a circuit called a
Summer
Multiplier
Divider
Mixer
13906. Mixing for frequency conversion is the same as
Rectification
AM
Linear summing
Filtering
13907. Which of the following is not a major advantage of FM over AM?
Greater efficiency
Noise immunity
Capture effect
Lower complexity and cost
13908. The primary disadvantage of FM is its
Higher cost and complexity
Excessive use of spectrum space
Noise susceptibility
Lower efficiency
13909. Noise is primarily
High-frequency spikes
Lowe-frequency variations
Random level shifts
Random frequency variations
13910. The receiver circuit that rids FM of noise is the
Modulator
Demodulator
Limiter
Low-pass filter
13911. The AM signals generated at a low level may only be amplified by what type of
amplifier?
Class A
Class B
Class C
All of the above
13912. SSB means
Single sideband with suppressed carrier

Single sideband with carrier
Double sideband with no carrier
Single sideband with reduced carrier
13913. A circuit used to select the desired output from a mixer
Transformer
Resonant circuit
Filter
Phase-shift circuit
13914. What is the output of a balanced modulator?
AM
DSB
SSB
ISB
13915. The acronym SSSC refer to
Suppressed sideband, single carrier
Suppressed sideband, suppressed carrier
Single sideband, suppressed carrier
Single sideband, single carrier
13916. Which process occurs in the receiver?
Demodulation
Reception
Modulation
Recreation
13917. What is usually used to demodulate SSB or CW signal?
PLL
BFO
Ratio detector
All of these
13918. Which of the following is the most widely used amplitude modulator
Diode detector
PLL circuit
VCO
All of these
13919. Which of the following is the most widely used balanced modulator
Full-wave bridge circuit
Balanced bridge modulator
Lattice modulator
None of these

13920.

[Type the
document title]
13921.

13922.

[Type the document subtitle]
13923.
13924.
13925.

13926.
13927.
13928.
13929.

1.

H

13930.
13931.

13932.
13933.
ECE BOARD PROBLEMS
13934.
APRIL 1999 – NOVEMBER 2002
13935.
13936.
13937.
(ECE Board Problem, November 2001) “Compulsory interconnection”
13938.
13939.
a.) EO 59
13940.
b.) EO 546
13941.
c.) EO 109
13942.
d.) Act 3846
13943.
13944.
(ECE Board Problem, November 2002) A single measuring circuit having a
resistor if 10 kΩ is connected in series with a 0.5 μF capacitor. What is affective
bandwidth?
13945.
13946.
a.) 50 kHz
13947.
b.) 5 Hz
13948.
c.) 50 Hz
13949.
d.) 500 Hz
13950.
13951.
(ECE Board Problem, April 1999) An aircraft deviation measured by an ILS
localizer.
13952.
13953.
a.) Altitude
13954.
b.) Ground Speed
13955.
c.) Vertical
13956.
d.) Horizontal
13957.
13958.
(ECE Board Problem, November 2001) In order to have a maximum power
transfer, what must be the relation of the input circuit impedance?
13959.
13960.
a.) Equal Impedance
13961.
b.) Infinity
13962.
c.) Zero
13963.
d.) Less Than
13964.
13965.
(ECE Board Problem, November 2001) The ratio of the speed of the light in
vacuum to the speed of the light in a material.
13966.
13967.
a.) Index of Refraction
13968.
b.) Dielectric Constant
13969.
c.) Velocity Factor
13970.
d.) Permittivity
13971.
13972.

13973.
13974.
13975.
13976.
(ECE Board Problem, November 2001) What is the radiation pattern of a half –
wave dipole?
13977.
13978. a.) Doughnut Shape
13979.
b.) Bi-Directional
13980.
c.) Unidirectional
13981.
d.) Omnidirectional
13982.
13983.
13984.
(ECE Board Problem, November 2001) It is produced when an object travels
faster than the speed of sound.
13985.
13986.
a.) Shock Wave
13987.
b.) Ultrasound
13988. c.) Sonic Wave
13989. d.) Light Wave
13990.
13991.
(ECE Board Problem, November 2001) The time used for reference for
determining the capacity of accepting calls for telephone system.
13992.
13993. a.) 12 MN
13994.
b.) High Usage Hour
13995. c.) 12NN
13996. d.) Low Usage Hour
13997.
13998.
(ECE Board Problem, November 2001) The term used for deafness of higher
frequencies due to old age.
13999.
14000. a.) Ear Deafness
14001.
b.) Cortial Deafness
14002. c.) Tinnitus
14003. d.) Presbycusis
14004.
14005.
(ECE Board Problem, November 2002) Single side band emission is most
frequently used in what frequency band?
14006.
14007. a.) LF
14008.
b.) HF
14009. c.) MF
14010. d.) VLF
14011.
14012.
(ECE Board Problem, November 2001) A device that converts voice to data.
14013.

14014. a.) Vocoder
14015.
b.) Covoder
14016. c.) Modern
14017. d.) Repeater
14018.
14019.
(ECE Board Problem, November 2001) A microwave device which permits
signal only in one direction.
14020.
14021. a.) RF Emitter
14022.
b.) Capacitor
14023. c.) Varactor and triac
14024. d.) Ferrite Isolator
14025.
14026.
14027.
(ECE Board Problem, November 2001) A very small band of frequency that is
used to protect interference of adjacent frequency.
14028.
14029. a.) Guard
14030.
b.) Carrier
14031. c.) Modulating
14032. d.) Tolerance
14033.
14034.
(ECE Board Problem, November 2001) It is a communication system operation
where the receiving station controls the effective data transmission rate at the sending
station.
14035.
14036. a.) Pacing
14037.
b.) Polling
14038. c.) Handshaking
14039. d.) Contention
14040.
14041.
(ECE Board Problem, November 2001) Where is the AGC in the IF amplifier
derived?
14042.
14043. a.) Mixer
14044.
b.) Rf Amplifier
14045. c.) Detector
14046. d.) Local Oscillator
14047.
14048.
(ECE Board Problem, November 2002) What is the voltage in a line, open
terminated at the end, quarter-wavelength from the termination?
14049.
14050. a.) Minimum
14051.
b.) Maximum
14052. c.) The same
14053. d.) Increasing

14054.
14055.
(ECE Board Problem, November 2001) What is the cellular system used in
Europe?
14056.
14057. a.) GSM
14058.
b.) TACS
14059. c.) AMPS
14060. d.) NMT
14061.
14062.
(ECE Board Problem, November 2001) Satellite revolution in the same direction
as the earth's rotation.
14063.
14064. a.) Retrograde
14065.
b.) Accelerated
14066. c.) Deccelerated
14067. d.) Posigrade
14068.
14069.
(ECE Board Problem, November 2001) What is meant by the term radiation
resistance of an antenna?
14070.
14071. a.) The resistance in the trap coils to received signal.
14072.
b.) An equipment resistance that would dissipate the same amount of
power as that radiated from an antenna
14073. c.) The specific impedance of an antenna.
14074. d.) Losses in the antenna elements and feed line.
14075.
14076.
(ECE Board Problem, November 2001) How do you connect two digital terminal
equipment (DTE) in the absence of a modem?
14077.
14078. a.) Line Bridging.
14079.
b.) Direct connection with the use of a null modem.
14080. c.) Sharing of line.
14081. d.) Using a router.
14082.
14083.
(ECE Board Problem, April 2002) __________ demodulates an FM signal.
14084.
14085. a.) Frequency Discriminator
14086.
b.) Frequency Multiplier
14087. c.) Diode Detector
14088. d.) IF Amplifier
14089.
14090.
(ECE Board Problem, April 2000) The effect of multi mode propagation caused
the rays leaving the fiber to interfere constructively and destructively as they leave the
end of the fiber, this effect is called ________.
14091.
14092. a.) multi mode Interference

14093.
b.) Modal Delay Spreading
14094. c.) multi mode Effect
14095. d.) Single Modal Effect
14096.
14097.
(ECE Board Problem, November 2000)What is the maximum number of lines for
any building other than a one or two story residential building to be required a service
entrance facility under ECE building code?
14098.
14099. a.) Two Lines
14100.
b.) Five Lines
14101. c.) Three Lines
14102. d.) Not Required
14103.
14104.
(ECE Board Problem, November 2000) Which of the following is not part of the
audio frequency section of the radio transmitter?
14105.
14106. a.) AF Voltage
14107.
b.) Microphone
14108. c.) Master Oscillator
14109. d.) AF power Amplifier
14110.
14111.
(ECE Board Problem, November 2000) Which of the following solution will you
prescribed to a telegraph transmitter power supply to avert a chirp?
14112.
14113. a.) Resonate power supply filters.
14114.
b.) Decrease the voltage of power supply.
14115. c.) Regulate the power supply voltage
14116. d.) Decrease current output.
14117.
14118.
(ECE Board Problem, April 2000) What is the term for the ratio of actual velocity
at which a signal travels through a line to the speed of light in a vacuum?
14119.
14120. a.) Surge Impedance
14121.
b.) Characteristics Impedance
14122. c.) Standing Wave Ratio
14123. d.) Velocity Factor
14124.
14125.
(ECE Board Problem, April 1999) Which part of the HF marine antenna safety
link is intended to be broken during the unusual movement of the ship?
14126.
14127. a.) Halkyard
14128.
b.) Weak Part
14129. c.) Mainmast
14130. d.) Foremast
14131.
14132.
(ECE Board Problem, November 2002) A PCM has a 30 kHz sampling frequency.

What is the maximum input frequency?
14133.
14134. a.) 15 kHz
14135.
b.) 60 kHz
14136. c.) 45 kHz
14137. d.) 30 kHz
14138.
14139.
(ECE Board Problem, April 1999) What is the capture effect?
14140.
14141. a.) The weak signal received is the only demodulated signal.
14142.
b.) All signals on a frequency are demodulated by an AM receiver.
14143. c.) All signals on a frequency are demodulated by an AM receiver.
14144. d.) The loudest signal received is the only demodulated signal.
14145.
14146.
(ECE Board Problem, April 2000) Which of the following microwave antenna is
normally used when obtaining an omni – directional radiation requirement?
14147.
14148. a.) Grid Type
14149.
b.) Whip
14150. c.) Bicone
14151. d.) Parabolic
14152.
14153.
(ECE Board Problem, April 1999) What is being measured in RADAR theory to
complete the determination of a distance to a target or an object, after a high radio
frequency signal is transmitted to a target?
14154.
14155. a.) Transmission time from the source to target.
14156.
b.) Transmission time from target back to source.
14157. c.) Echo time of the object to the source.
14158. d.) Complete signal transmission from source and back.
14159.
14160.
(ECE Board Problem, April 2000) What is the radio horizon distance between a
150 ft. transmitting station and a 70 ft. receiving station?
14161.
14162. a.) 82.46 mi
14163.
b.) 82.46 km
14164. c.) 29.15 km
14165. d.) 29.15 mi
14166.
14167.
(ECE Board Problem, November 2000) Telephone channel has a band-pass
characteristics occupying the frequency range of _____.
14168.
14169. a.) 300-2700 Hz
14170.
b.) 300-3400 Hz
14171. c.) 300-3000 Hz
14172. d.) 300-400 Hz

14173.
14174.
14175.
14176.
(ECE Board Problem, November 1999) This the Nordic analogue mobile radio
telephone system originally used in Scandinavia.
14177.
14178. a.) NMT
14179.
b.) GSM
14180. c.) PCN
14181. d.) PCS
14182.
14183.
(ECE Board Problem, April 2000) When a signal bandwidth of a TV broadcast
over the radio is lessen, using a technique that limits a picture frequency, this is referred
to as ________.
14184.
14185. a.) Video Control
14186.
b.) Interlaced Scanning
14187. c.) Demodulation
14188. d.) Line Scanninh
14189.
14190.
(ECE Board Problem, April 1999) These are bend of light wavelengths that are
too short to be seen by the human eye.
14191.
14192. a.) Visible
14193.
b.) Amber
14194. c.) Infrared
14195. d.) Ultraviolet
14196.
14197.
(ECE Board Problem, April 2000) How does the length of the director element of
a parasitic element beam antenna compare with that of the driven element?
14198.
14199. a.) It is about 5% longer.
14200.
b.) It is one-half as long.
14201. c.) It is twice as long.
14202. d.) It is about 5% shorter.
14203.
14204.
(ECE Board Problem, November 2001) Refers to the numeric ratio relating to the
radiated signal strength of an antenna to that of another antenna.
14205.
14206. a.) Antenna Loss
14207.
b.) Antenna Gain
14208. c.) Antenna Bandwidth
14209. d.) Antenna Efficiency
14210.
14211.
(ECE Board Problem, November 2001) What will happen if there is a great
mismatch between the load and the source?

14212.
14213. a.) High SWR
14214.
b.) Low SWR
14215. c.) Medium SWR
14216. d.) SWR of 1
14217.
14218.
(ECE Board Problem, November 2001) What is used to connect a computer if it is
far from the host?
14219.
14220. a.) Modem
14221.
b.) AVR
14222. c.) Waveguide
14223. d.) Transponder
14224.
14225.
(ECE Board Problem, November 2001) Range of frequency that an antenna will
perform well.
14226.
14227. a.) Antenna Bandwidth
14228.
b.) Antenna Beamwidth
14229. c.) Antenna Efficiency
14230. d.) Antenna Directivity
14231.
14232.
(ECE Board Problem, November 2001) What is the fastest memory of a
computer?
14233.
14234. a.) RAM
14235.
b.) Cache
14236. c.) Magnetic Disk
14237. d.) Magnetic Tape
14238.
14239.
(ECE Board Problem, November 2001) What composes the electromagnetic
waves?
14240.
14241. a.) Electric and Magnetic Field
14242.
b.) Acoustic and Water Wave
14243. c.) Current and Voltage
14244. d.) Pressure and Frequency
14245.
14246.
(ECE Board Problem, November 2001) One of the characteristics of an early
facsimile machine which electromechanical device.
14247.
14248. a.) Receive start/stop bits to synchronize.
14249.
b.) Using heat that would burn the image into heat.
14250. c.) Using tubes to amplify the signal.
14251. d.) Using fire to heat the thermal paper.
14252.

14253.
(ECE Board Problem, November 2001) What is the cable requirement for one or
two-storey building that has more than five telephone lines?
14254.
14255. a.) Service Entrance
14256.
b.) Service Cable
14257. c.) Building Cable
14258. d.) Residential Cable
14259.
14260.
(ECE Board Problem, November 2001) A transmission line consisting of center
conductor, a plastic insulation, a fine wire braid shield and outer plastic insulation as a
jacket.
14261.
14262. a.) coaxial cable
14263.
b.) twin cable
14264. c.) wave guide
14265. d.) twisted pair
14266.
14267.
(ECE Board Problem, November 2001) The executive branch of government incharge of policy making in telecommunication.
14268.
14269. a.) National Telecommunication Commission
14270.
b.) Telecommunication Control Bureau
14271. c.) Department of Transportation and Communication
14272. d.) Bureau of Communication
14273.
14274.
(ECE Board Problem, November 2001) What is the dBSPL of an auditorium with
contemporary music?
14275.
14276. a.) 95 – 100 dB
14277.
b.) 40 – 50 dB
14278. c.) 50 – 60 dB
14279. d.) 70 – 80 dB
14280.
14281.
(ECE Board Problem, November 2001) What is the symbol designated for a
frequency modulated carrier for a single telephony transmission?
14282.
14283. a.) F3E
14284.
b.) F3F
14285. c.) G3F
14286. d.) G3E
14287.
14288.
(ECE Board Problem, November 2001) The layer that is responsible for sky wave
propagation and the highest layer?
14289.
14290. a.) D
14291.
b.) F2

14292. c.) A
14293. d.) E
14294.
14295.
(ECE Board Problem, November 2001) Process of impressing lower intelligent
frequency to higher frequency.
14296.
14297. a.) modulation
14298.
b.) detection
14299. c.) multiplexing
14300. d.) scrambling
14301.
14302.
(ECE Board Problem, November 2001) Find the suitable ground plane for a
frequency of 220 MHz.
14303.
14304. a.) 0.5 m
14305.
b.) 0.24 m
14306. c.) 0.34 m
14307. d.) 1.2 m
14308.
14309.
(ECE Board Problem, November 2001) The term used for the mechanism
RADAR searchimg for an object.
14310.
14311. a.) scanning
14312.
b.) tracing
14313. c.) lobing
14314. d.) nodding
14315.
14316.
(ECE Board Problem, November 2001)
14317.
14318. a.) variable capacitance
14319.
b.) variable resistance
14320. c.) variable inductance
14321. d.) piezoelectric effect
14322.
14323.
(ECE Board Problem, November 2001) What do you call the telephone system
connecting residence and business establishments?
14324.
14325. a.) Public Telephone System
14326.
b.) Pay Phone System
14327. c.) Private Network System
14328. d.) Touch Tone System
14329.
14330.
(ECE Board Problem, April 2000) In Broadcasting, an area characterized to have
no interference but wit fading or intermittent variations in intensity is _______.
14331.
14332. a.) Primary Service Area

14333.
b.) Intermediate Service Area
14334. c.) Tertiary Service Area
14335. d.) Secondary Service Area
14336.
14337.
(ECE Board Problem, April 2002) Information capacity is proportional.
14338.
14339. a.) bandwidth
14340.
b.) noise
14341. c.) power
14342. d.) flux
14343.
14344.
(ECE Board Problem, April 2002) What is the number of lines per field in an
NTSC TV?
14345.
14346. a.) 525
14347.
b.) 262.5
14348. c.) 625
14349. d.) 312.5
14350.
14351.
(ECE Board Problem, April 2002) It refers to the time required for a signal to
complete one cycle.
14352.
14353. a.) Wavelength
14354.
b.) Frequency
14355. c.) Amplitude
14356. d.) Period
14357.
14358.
(ECE Board Problem, April 2002) What happens when the separation between
two conductors having the same diameter decreases?
14359.
14360. a.) The characteristic impedance decreases.
14361.
b.) The characteristic impedance increases,
14362. c.) The characteristic impedance does not change.
14363. d.) Cannot be determined
14364.
14365.
(ECE Board Problem, November 2001) The government entity that regulates the
cable television industry in the Philippines.
14366.
14367. a.) Executive Commission
14368.
b.) House of Representatives
14369. c.) NTC
14370. d.) DOTC
14371.
14372.
(ECE Board Problem, November 2001) A modulation which is amplitude
modulated that consist of recurrent pulses.
14373.

14374. a.) PAM
14375.
b.) PWM
14376. c.) PPM
14377. d.) AM
14378.
14379.
(ECE Board Problem, November 2001) Which of the following consist of twp of
the three primary colors in television signal? a.)red, b)violet,c)yellow, and d)blue.
14380.
14381. a.) a and b
14382.
b.) b and c
14383. c.) c and d
14384. d.) a and d
14385.
14386.
(ECE Board Problem, November 2001) Which of the navigational equipment
which utilizes the principle of RADAR but is use in underwater?
14387.
14388. a.) TACAN
14389.
b.) SONAR
14390. c.) TASI
14391. d.) RADAR
14392.
14393.
(ECE Board Problem, November 2001) How can cross – modulation in a receiver
be reduced?
14394.
14395. Adjust the pass band tuning.
14396.
b.) Increase RF amplifier gain and decrease AF amplifier gain
14397. c.) Installing a filter at the receiver
14398. d.) Using a better antenna
14399.
14400.
(ECE Board Problem, November 2001) The circuit that convert signal in order
that it can be fed to the medium suitable for transmission.
14401.
14402. a.) Modulator
14403. b.) Mixer
14404. c.) Receiver
14405. d.) Transmitter
14406.
14407.
(ECE Board Problem, November 2001) A type of Class C amplifier which has 1
to 10 times the gain of input used to generate frequency multiple of the fundamental
frequency.
14408.
14409. a.) Frequency Generator
b.) Frequency Multiplier
14410.
14411. c.) Frequency Amplifier
14412. d.) Frequency Divider
14413.

14414.
(ECE Board Problem, November 2001) The definition of modulation index:
14415.
14416. a.) The radio of deviation frequency and modulating
14417.
b.) The ratio of the maximum deviation frequency and maximum
modulating frequency
14418. c.) The ratio of actual deviation to the maximum deviation
14419. d.) The ratio of the maximum deviation to the actual deviation
14420.
14421.
(ECE Board Problem, November 2001) One of the following can be best attained
by a trap antenna in radio communication?
14422.
14423. a.) Increase transmitter gain
14424.
b.) Directionality
14425. c.) Effective filter to noise signal
14426. d.) Multi frequency band operation
14427.
14428.
(ECE Board Problem, November 2000)when we talk of the study of acoustics, a
sound is considered _____wave.
14429.
14430. a.) Circular
14431.
b.) Light
14432. c.) Laser
14433. d.) Longitudinal
14434.
14435.
(ECE Board Problem, November 1999) One of the major components required
under the global maritime distress and safety system.
14436.
14437. a.) Provision of Morse code
14438.
b.) Provision of radio telegraph operator
14439. c.) Provision of facsmile
14440. d.) Provision of radio personnel
14441.
14442.
(ECE Board Problem, November 1999) A resultant effect in launching a satellite
from the earth caused by both forward motion away from the earth that produces inertia
tending the satellite to travel in straight line upwards and the gravitational pull towards
the earth is referred to as _______.
14443.
14444. a.) Centripetal acceleration
14445.
b.) Gravity
14446. c.) Weight of satellite
14447. d.) Satellite Speed
14448.
14449.
(ECE Board Problem, April 2000) A RADAR set receiver has normally a
________ mixer stage.
14450.
14451. a.) Tunnel diode

14452.
b.) FET
14453. c.) Class A
14454. d.) Silicon Crystal
14455.
14456.
(ECE Board Problem, April 1999) Refers to a connector that normally connects
RG – 213 coaxial cable to an HF transceiver.
14457.
14458. a.) N-type Cable
14459.
b.) F-type Cable
14460. c.) PL-259
14461. d.) BNC
14462.
14463.
(ECE Board Problem, November 2000) Which of the following refers to the
bandwidth of optical fiber?
14464.
14465. a.) 1 Hz-30,000 Hz
14466.
b.) 1 kHz-300 kHz
14467. c.) 1MHz-300 MHz
14468. d.) 1MHz-500MHz
14469.
14470.
(ECE Board Problem, April 1999) How many commissioners does the National
Telecommunications Commission have?
14471.
14472. a.) 1
14473.
b.) 5
14474. c.) 3
14475. d.) 2
14476.
14477.
14478.
14479.
14480.
14481.
(ECE Board Problem, November 2000) Which one is referred to the reduction of
receiver gain caused by strong signal from nearby transmission of adjacent frequency?
14482.
14483. a.) Intermodulation
14484.
b.) Quieting
14485. c.) Fading
14486. d.) Desensitizing
14487.
14488.
(ECE Board Problem, April 2000) Transmission of information through a
communication modem is intended to transmit digital information over which of the
following type of communication medium?
14489.
14490. Digital
14491. Hybrid

14492. Radio
14493. Analog
14494.
14495.
(ECE Board Problem, April 1999) Determine from the following an advantage
using a trap antenna.
14496.
14497. It has directivity in the high frequency bands.
14498. Can be used for multiband operation.
14499. Minimizes harmonic radiation.
14500. Has high gain.
14501.
14502.
(ECE Board Problem, November 2002) What do you call a circuit in PCM
wherein the instantaneous sinusoidal wave is regular sample and converted to a discrete
amplitude levels?
14503.
14504. a.)analog to digital converter
14505. b.) sample and hold
14506. c.) modem
14507. d.) multiplexer
14508.
14509.
(ECE Board Problem, April 1999) Determine from the following, possible cause
for a slow drift of frequency in self-excited transmitter oscillator circuits resulting to poor
frequency stability.
14510.
14511. a.)Faulty capacitors, resistors, tubes or transistors.
14512. b.) Loose shielding.
14513. c.) Heating in the oscillator device causing a change in electrical
characteristics.
14514. d.) Loose connections in the oscillator, amplifier or antenna circuits.
14515.
14516.
(ECE Board Problem, November 2000) Which of the following penalty is
provided under the existing telecommunications law, should an international carrier
unable to comply with its obligation to provide local exchange service in un-served and
underserved areas within three years from grant of authority?
14517.
14518. a.)Financial penalty in accordance with existing schedules.
14519. b.)Cancellation of its authority.
14520. c.) Given one year to comply.
14521. d.) Given two years to comply.
14522.
14523.
(ECE Board Problem, April 2000) In basic transmitter such as CW transmission,
the rounding off of square wave emission will reduce________.
14524.
14525. Reach
14526. Voltage
14527. Bandwidth

14528. Transmitter power
14529.
14530.
(ECE Board Problem, November 1999) Refers to one possible cause for an abrupt
frequency variation in a self-excited transmitter oscillator circuits resulting to a poor
frequency stability to hold a constant oscillation.
14531.
14532. Poor soldered connections.
14533. Heating of capacitor in the oscillator.
14534. DC and RF ac heating of resistors, which cause change in values.
14535. Aging which cause change condition in parts characteristics.
14536.
14537.
14538.
(ECE Board Problem, November 2000)which of the following is referred to the
SYN character of ASCII code?
14539.
14540. a.)32H
14541. b.)16H
14542. c.)64H
14543. d.)8H
14544.
14545.
(ECE Board Problem, November 1999)In a basic radio transmitter, what is the
main disadvantage of a single-tube transmitter?
14546.
14547. a.)Frequency Instability
14548. b.)Non-portable
14549. c.)Heating Effect
14550. d.)Bulky
14551.
14552.
(ECE Board Problem, April 2000) One of the following is considered the largest
source of signal power loss in the use of fiber optic as a communication medium such as
due to misalignment.
14553.
14554. a.) Bending
14555. b.) Scattering
14556. c.) Connection
14557. d.) Absorption
14558.
14559.
(ECE Board Problem, November 2000) Statement, which best describe a mixing
process in radio communication.
14560.
14561. a.) Process of eliminating noise through phase differentiation.
14562. b.) Producing sum and difference of two frequencies from a combination of
two signals.
14563. c.) Processing of eliminating noise through phase comparison.
14564. d.) Combination of two signals to form three or more output signals.
14565.

14566.
(ECE Board Problem, November 2001)What is the input impedance equivalent of
an open-ended transmission line which is longer than a quarter wavelength?
14567.
14568. a.) Open equivalent
14569. b.) Equivalent to reactive circuit
14570. c.) As resistive equivalent
14571. d.) As pure inductor
14572.
14573.
(ECE Board Problem, November 2000) How would you isolate data
communications faults in a basic error determination technique?
14574.
14575. a.) Test each cards.
14576. b.) Simulate the loop.
14577. c.) Test each repeater.
14578. d.) Carry out loopback test.
14579.
14580.
(ECE Board Problem, April 2000) Which of the following describes its system
services control point, logical units and physical units as network addressable units in a
data network?
14581.
14582. a.) Digital Network Architecture
14583. b.) Internetworking
14584. c.) Interconnection Point
14585. d.) System Network Architecture
14586.
14587.
(ECE Board Problem, November 2000) A telecommunications law that
deregulates the paging services in the country.
14588.
14589. a.) E. O. 125
14590. b.) Act 3846
14591. c.) Act 3396
14592. d.) R.A. 7925
14593.
14594.
14595.
(ECE Board Problem, April 2000) What refers to breaking up the data into blocks
with some bounded size?
14596.
14597. a.) Framing
14598. b.) Segmentation
14599. c.) Encapsulation
14600. d.) Packing
14601.
14602.
(ECE Board Problem, November 2001) What is the apogee of a geosynchronous
satellite’s temporary orbit before be placed in the geosynchronous orbit?
14603.
14604. a.) 50,000 mi

14605. b.) 40,000 mi
14606. c.) 22,300 mi
14607. d.) 30,000 mi
14608.
14609.
(ECE Board Problem, November 2001) A device used in television broadcast that
prevents any FM signal from entering into the visual transmitter and vice versa.
14610.
14611. a.) Duplexer
14612. b.) Mixer
14613. c.) Diplexer
14614. d.) Synchronizer
14615.
14616.
(ECE Board Problem, November 1999) A sound intensity that could cause painful
sensation in the human ear.
14617.
14618. a.) Threshold of Sense
14619. b.) Threshold of Pain
14620. c.) Hearing Threshold
14621. d.) Sensation Intensity
14622.
14623.
(ECE Board Problem, April 1999) What is the first symbol of radio signal
emission having an amplitude modulated main carrier single sideband suppressed carrier?
14624.
14625. a.) C
14626. b.) A
14627. c.) J
14628. d.) H
14629.
14630.
(ECE Board Problem, November 1999) What us the baseband frequency of
standard FDM basic super group?
14631.
14632. 300 to 600 kHz
14633. 312 to 552 kHz
14634. 60 to 2540 kHz
14635. 60 to 180 kHz
14636.
14637.
(ECE Board Problem, November 1999) Very High (radio) Frequency in the
spectrum refers to _______ waves.
14638.
14639. Centimetric
14640. Hectometric
14641. Kilometric
14642. Metric
14643.
14644.
100. (ECE Board Problem, April 1999) What wave trap frequency is used in the
video amplifier?

14645.
14646.
39.75 MHz
14647.
41.25 MHz
14648.
4.5 MHz
14649.
47.25 MHz
14650.
14651.
101.(ECE Board Problem, November 2000) Which of the following best
described the primary source of errors in the transmission of data over telephone
networks?
14652.
14653.
Thermal Noise
14654.
Crosstalk
14655.
Impulse Noise
14656.
Intermodulation
14657.
14658.
14659. 102. (ECE Board Problem, April 1999) Which part of the HF marine antenna handles
the broken safety link, in case it results collision, grounding or storm?
14660.
14661. The lead-in.
14662. The foremast.
14663. The strong part.
14664. The halyard.
14665.
14666. 103. (ECE Board Problem, April 2000) A reduction in receiver sensitivity caused by
unwanted high-level adjacent channel signals.
14667.
14668.
Intermodulation
14669.
Overloading
14670.
Interference
14671.
Desensitizing
14672.
14673.
14674.
14675.
14676.
104. (ECE Board Problem, November 2000) Which of the following system uses
frequency band 870-890 MHz as a transmit band of its base station?
14677.
14678. Total Access Communication System (TACS)
14679. Nordic Mobile Telephone (NMT)
14680. Public Mobile System (PMS)
14681. Advance Mobile Phone Services (AMPS)
14682.
14683.
105. (ECE Board Problem, November 2000) Refers to a mobile earth station in
the mobile-satellite service located on board ship.
14684.

14685. Mobile Station
14686. Ship Station
14687. Ship Earth Station
14688. Mobile Satellite Station
14689.
14690.
106. (ECE Board Problem, November 2002) What is the electric field strength in
millivolts per meter if the transmitted power is 30kW, at a distance of 5km?
14691.
14692. 120 mV/m
14693. 190 mV/m
14694. 150 mV/m
14695. 30 mV/m
14696.
14697.
107. (ECE Board Problem, November 2000) Frequency band where Total Access
Communication System is allocated.
14698.
14699. 86-869 MHz; 821-824 MHz
14700. 870-890 MHz; 825-845 MHz
14701. 851-866 MHz; 806-821 MHz
14702. 935-960 MHz; 890-915 MHz
14703.
14704.
108. (ECE Board Problem, November 2000) Which of the following is used as a
standard channel spacing for AM broadcast in the Philippines?
14705.
14706. 25 kHz
14707. 12.5 kHz
14708. 40 kHz
14709. 9 kHz
14710.
14711.
109. (ECE Board Problem, November 2000) What is the frequency separation
between the aural carrier and the lower limits of the total channel band of a monochrome TV
broadcast?
14712.
14713. 1.25 MHz
14714. 4.5 MHz
14715. 3.0 MHz
14716. 5.75 MHz
14717.
14718.
110. (ECE Board Problem, November 2000) Which salellite transponder has the
most number of mixers?
14719.
14720.
Regenerative
14721.
Broadband
14722.
Double-Conversion
14723.
Channelized
14724.

14725.
111. (ECE Board Problem, November 2000) An advantage of fiber optic co-axial
cable as a result of coupling signals from one to the other due to changing magnetic field in
one or both.
14726.
14727. Feedback
14728. Crosstalk
14729. Electric Hazard
14730. Shielding
14731.
14732.
112. (ECE Board Problem, April 2001) How can even-order harmonics be
reduced or prevented in transmitter amplifier design?
14733.
14734. By using a push-push amplifier
14735. By using push-pull amplifier
14736. By operating Class C
14737. By operating Class AB
14738.
14739.
113. (ECE Board Problem, April 2002) With which emission type is the capture
effect most pronounced?
14740.
14741. FM
14742. SSB
14743. AM
14744. CW
14745.
14746.
114. (ECE Board Problem, April 2002)What is the term used to refer to the
reception blockage of one FM-phone signal by another FM-phone signal?
14747.
14748. Desensitization
14749. Cross-modulation Interference
14750. Capture Effect
14751. Frequency Discrimination
14752.
14753.
115. (ECE Board Problem, April 2002) What is the primary purpose of an RF
amplifier in a receiver?
14754.
14755. To provide most of the receiver gain.
14756. To develop the AGC voltage.
14757. To improve the receiver’s noise figure.
14758. To vary\ the receiver image rejection by utilizing the AGC.
14759.
14760.
116. (ECE Board Problem, April 2002)What is the product of the power fed to the
antenna and its power gain?
14761.
14762. Antenna Power
14763. ERP

14764. PEP
14765. Peak Power
14766.
14767.
117. (ECE Board Problem, April 1999) What is the reason why Hertz antenna is
not normally used to radio station or receiver or transmitter antenna that has frequency below
2MHz?
14768.
14769. The antenna receives more inter-modulation signal.
14770. The antenna receive side becomes non-receptive.
14771. The antenna will be physically very small.
14772. The antenna will be physically very large.
14773.
14774.
118. (ECE Board Problem, November 1999) In the study of transmission cable,
twin lead is also referred to as________.
14775.
14776. Twisted pair
14777. Double cable
14778. Ribbon cable
14779. Open pair
14780.
14781.
119. (ECE Board Problem, November 1999) In an open architecture concept of
data communication, one of the following is not a function of a control layer.
14782.
14783. Fault correction
14784. Congestion control
14785. Fault detection
14786. Integrity of data
14787.
14788.
120. (ECE Board Problem, November 1999)What are the two legislative function
of the International Telecommunications Union in its international conference issues on
orbital resources?
14789.
14790.
Assign frequencies and organizes conferences.
14791.
Allocates frequency bands for the services and determine the principle of
distribution of orbit/spectrum resources.
14792.
Determine the principles of spectrum distribution and assignment of frequencies.
14793.
Conduct conferences and allocation of orbital slot.
14794.
14795.
121. (ECE Board Problem, April 2002)What transmission medium is capable of
carrying up to 10Gbps capacity?
14796.
14797. Twisted pair
14798. Optical fiber
14799. Coax
14800. Microwave link
14801.

14802.
122. (ECE Board Problem, April 2002) What is the controlling node of a star
topology system?
14803.
14804. Modem
14805. Codec
14806. Hub
14807. ADC
14808.
14809.
123. (ECE Board Problem, April 2002) What is the most efficient topology used
by small business organization?
14810.
14811. Mesh
14812. Star
14813. Bus
14814. Ring
14815.
14816.
124. (ECE Board Problem, April 2002)Which of the following network topology
has the fastest speed?
14817.
14818. Star
14819. Ring
14820. Bus
14821. Mesh
14822.
14823.
125. (ECE Board Problem, April 2002) The latest and most advanced equipment
in data communications is a/an___________.
14824.
14825. Amplifier
14826. Simulator
14827. Protocol analyzer
14828. Spectrum analyzer
14829.
14830.
126. (ECE Board Problem, April 2002) Which has the highest priority in radio
telephone communication?
14831.
14832. Distress
14833. Safety
14834. Urgency
14835. Roger
14836.
14837.
127. (ECE Board Problem, April 2002) In satellite communications, what is the
frequency of the V-band?
14838.
14839. 27-40 GHz
14840. 4-8 GHz
14841. 8-12GHz

14842. 40-75 GHz
14843.
14844.
128. (ECE Board Problem, April 2002) What is meant by the term antenna gain?
14845.
14846. The numerical ratio relating the radiated signal strength of an antenna to
that of another antenna.
14847. The ratio of the signal in the forward direction to the signal in the back direction.
14848. The ratio of the amount of power to produce by the antenna compared to the
output power of the transmitter.
14849. The final amplifier gain minus the transmission line losses.
14850.
14851.
129. (ECE Board Problem, April 2002) What is an advantage using a trap
antenna?
14852.
14853. It has antenna gain
14854. It minimizes harmonic radiation
14855. It has high directivity in the high frequency bands
14856. It may be used for multiband operations
14857.
14858.
130. (ECE Board Problem, April 2002) What is the wavelength of a shorted stub
used to absorb even harmonics?
14859.
14860. 0.5 wavelength
14861. 1/3 wavelength
14862. 0.25 wavelength
14863. 1/8 wavelength
14864.
14865.
131. (ECE Board Problem, November 2002) Who coined the term fiber optics?
14866.
14867. Hansell
14868. Hopkins
14869. N.S. Kapany
14870. Van heel
14871.
14872.
132. (ECE Board Problem, April 2002) How does the length of the reflector
element of a parasitic beam antenna compare with that of a driven element?
14873.
14874. It is about 5% longer.
14875. It is about 5% shorter
14876. It is twice as long
14877. It is one-half as long
14878.
14879.
133. (ECE Board Problem, April 2001) In a half wave antenna, where are the
current nodes?
14880.
14881. At the ends

14882. At the center
14883. One-half of the way from the feed point toward the end.
14884. Three-quarters of the way from the feed point toward the end.
14885.
14886.
134. (ECE Board Problem, April 2002) Why is a loading coil often used with an
HF mobile antenna?
14887.
14888. To improve reception
14889. To lower the losses
14890. To lower the Q.
14891. To tune out the capacitive resistance.
14892.
14893.
135. (ECE Board Problem, April 2002) What is a frequency discriminator?
14894.
14895. A circuit for detecting FM signals
14896. A circuit for filtering two closely adjacent signals.
14897. An automatic band switching circuit.
14898. An FM generator.
14899.
14900.
136. (ECE Board Problem, April 2002) What is the period of a wave?
14901.
14902. The time required to complete one cycle.
14903. The number of degrees in one cycle.
14904. The number of zero crossing in one cycle.
14905. The amplitude of the wave.
14906.
14907.
137. (ECE Board Problem, April 2002) The implementing guidelines on
international satellite communications is___________.
14908.
14909. EO 467
14910. EO 846
14911. DO 11
14912. DO 88
14913.
14914.
138. (ECE Board Problem, April 2002) What was implemented in 1999 which has
the purpose of aiding the maritime navigation using satellite as well as advanced terrestrial
communication system?
14915.
14916. GMDSS
14917. AMPS
14918. GLONASS
14919. NAVSTAR
14920.
14921.
139. (ECE Board Problem, April 2002) Which of the following is not a DTE?
14922.
14923. Telephone set

14924. Computer
14925. Bridge
14926. Printer
14927.
14928.
140. (ECE Board Problem, April 2002)What is the transmission of data through a
different time slots?
14929.
14930. TDM
14931. FDM
14932. WDM
14933. CDM
14934.
14935.
141. (ECE Board Problem, April 2002) What is the parameter that affects the
computation of image frequency?
14936.
14937. Q
14938. fLO
14939. fIF
14940. D
14941.
14942.
142. (ECE Board Problem, April 2002) Which of the following could not be
observed in a microwave communications?
14943.
14944. LOS
14945. Wide BW
14946. Better Signal Penetration
14947. Directional Antenna
14948.
14949.
14950.
143. (ECE Board Problem, April 2002) The service area where the signal is
subject to fading with no objectionable interference.
14951.
14952. Primary service area
14953. Secondary service area
14954. Intermittent service area
14955. Quarternary service area
14956.
14957.
144. (ECE Board Problem, April 2002) By examining the following antenna type,
determine which is properly terminated?
14958.
14959. Non-resonant Type
14960. Half-wave Dipole
14961. Whip antenna Type
14962. Resonant Type
14963.
14964.
145. (ECE Board Problem, April 2001) What is the third letter symbol in the

emission designation for telemetry?
14965.
14966. F
14967. B
14968. D
14969. N
14970.
14971.
146. (ECE Board Problem, April 2002) What is the frequency tolerance of FM
broadcasting?
14972.
14973. 25 kHz
14974. 20 kHz
14975. 2 kHz
14976. 30 kHz
14977.
14978.
147. (ECE Board Problem, April 2001) Which of the following is commonly used
search engine?
14979.
14980. .edu
14981. www
14982. .org
14983. Excite
14984.
14985.
148. (ECE Board Problem, April 2001)When the electric field is perpendicular to
the surface of the earth, what is the polarization of the electromagnetic wave?
14986.
14987. Vertical
14988. Horizontal
14989. Circular
14990. Elliptical
14991.
14992.
149. (ECE Board Problem, April 2001) What is the deviation ratio of an FM
signal if the maximum allowable deviation is 12 kHz and the maximum intelligence
frequency is 4 kHz?
14993.
14994. 3
14995. 48
14996. 2/3
14997. 1/3
14998.
14999.
150. (ECE Board Problem, April 2002) What is the typical satellite
communications bandwidth?
15000.
15001. 20 MHz
15002. 30 MHz
15003. 40 MHz

15004. 500 MHz
15005.
15006.
151. (ECE Board Problem, April 2001) the following are not used in radio
communications, except________.
15007.
15008. Infrared
15009. Cosmic
15010. X-ray
15011. Gamma
15012.
15013.
152. (ECE Board Problem, April 2001) A modem which can be used to send data
and fax.
15014.
15015. Bell 212A
15016. ARQ
15017. Fax modem
15018. Data modem
15019.
15020.
153. (ECE Board Problem, April 2001) What is the output of a balanced
modulator.
15021.
15022. SSB
15023. DSB
15024. ISB
15025. VSB
15026.
15027.
154. (ECE Board Problem, April 2002) An emission technique where the total
current will be twice as much when the modulation index is doubled.
15028.
15029. J3E
15030. H3E
15031. A3E
15032. R3E
15033.
155. (ECE Board Problem, April 2001) Which of the following uses frequency
modulator circuit?
15034.
15035. A3E
15036. F3E
15037. H3E
15038. R3E
15039.
15040.
156. (ECE Board Problem, April 2002) What is used to display harmonics and
fundamental frequency?
15041.
15042. Oscilloscope
15043. Spectrum Analyzer

15044. Wattmeter
15045. Ohmmeter
15046.
15047.
157. (ECE Board Problem, November 2002) What is the free space loss, in dB, of
a microwave system when the frequency is 6 GHz at 40km apart?
15048.
15049. 170 dB
15050. 150 dB
15051. 160 dB
15052. 140 dB
15053.
15054.
158. (ECE Board Problem, April 2001) When the signal becomes weak, the base
will request the MTSO to find another site.
15055.
15056. Roaming
15057. Hand-off
15058. Frequency Re-use
15059. Cell splitting
15060.
15061.
159. (ECE Board Problem, April 2001) What is the interference between the
switching office and the mobile unit.
15062.
15063. Cell sites
15064. MTSO
15065. Microwave link
15066. Base station
15067.
15068.
160. (ECE Board Problem, April 2001) Which is not an omni-directional antenna?
15069.
15070. Vertical folded dipole
15071. Discone
15072. Rhombic
15073. Marconi
15074.
15075.
161. (ECE Board Problem, April 2001) Which satellite band is affected by VHF
signals?
15076.
15077. L
15078. C
15079. P
15080. Ku
15081.
15082.
162. (ECE Board Problem, April 2001) What is produced by over-modulation in
AM?
15083.
15084. Sidebands

15085. Jitter
15086. Glitch
15087. Spurious Signal
15088.
15089.
163. (ECE Board Problem, April 2001)_____ is the process of sending out the
information in all directions.
15090.
15091. Navigation
15092. Broadcasting
15093. Acoustics
15094. Telemetry
15095.
15096.
164. (ECE Board Problem, April 2001) How do you increase the electrical length
of an antenna?
15097.
15098. Add an inductor in parallel
15099. Add an inductor in series
15100. Add a capacitor in series
15101. Add a resistor in series.
15102.
15103.
165. (ECE Board Problem, April 2001) What is the usual electrical length of a
driven element in HF beam antenna?
15104.
15105. ¼ wavelength
15106. ½ wavelength
15107. ¾ wavelength
15108. 1 wavelength
15109.
15110.
166. (ECE Board Problem, April 2002) What is the point in the satellite as it
crosses the equator?
15111.
15112. Apogee
15113. Node
15114. Perigee
15115. Orbit
15116.
15117.
167. (ECE Board Problem, November 2001) Direct Distance Dialing is________.
15118.
15119. Private line
15120. Public line
15121. Lease line
15122. Dial-up
15123.
168. (ECE Board Problem, November 2001)A path wherein a satellite crosses in
the equator heading south.
15124.
15125. Ascending node

15126. Descending node
15127. Orbital
15128. Polar
15129.
15130.
169. (ECE Board Problem, November 2001) In what frequency band does 4-6
GHz fall in the satellite communications?
15131.
15132. C-Band
15133. L-Band
15134. X-band
15135. K-band
15136.
15137.
170. (ECE Board Problem, November 2001) A computer network found in the
same building.
15138.
15139. Local area network
15140. Wide area network
15141. Metropolitan area network
15142. PLL
15143.
15144.
171. (ECE Board Problem, April 2002) Which of the following antenna feedline
can easily be buried underground for a distance without adverse effects?
15145.
15146. Waveguide
15147. Twisted pair
15148. Coaxial cable
15149. Twin lead
15150.
15151.
172. (ECE Board Problem, April 1999) In the study of wave propagation, a
condition at which zero absorption of radio waves is describe as__________.
15152.
15153. Zero reflection medium
15154. Neutral medium
15155. Free space medium
15156. Non-active medium
15157.
15158.
173. (ECE Board Problem, November 1999) Which of the following in the radio
emission designation refers to the first symbol?
15159.
15160. Nature of signal modulating the main carrier
15161. Type of modulation of the main carrier
15162. Emission bandwidth
15163. Type of information
15164.
15165.
174. (ECE Board Problem, November 2000) The process of exchanging
predetermine codes and signals in telecommunications between two data terminals to

establish a connection is called.
15166.
15167. Hands-off
15168. Polling
15169. Handshake
15170. Demodulation
15171.
15172.
175. (ECE Board Problem, April 2000) It is an electronic instrument which can be
referred to as a miniature radio transmitter and can be made to generate signals at any desired
frequency, normally it is used for test purposes.
15173.
15174. Volt-ohm milliammeter
15175. Signal generator
15176. Oscilloscope
15177. Wavemeter
15178.
15179.
176. (ECE Board Problem, April 1999) A network interconnection facility which
is used to interconnect networks whose architectures are entirely different is called________.
15180.
15181. Bridge
15182. Router
15183. Gateway
15184. Repeater
15185.
15186.
177. (ECE Board Problem, November 1999) Type of multi-channel transmission
in the optic fiber communication that uses a twisted pair coupler to transmit two signals of
different wavelengths.
15187.
15188. Frequency-division multiplexing
15189. Forward-division multiplexing
15190. Pulse-code multiplexing
15191. Time-division multiplexing
15192.
15193.
15194.
15195.
15196.
178. (ECE Board Problem, April 2000) These are the rules in data
communications intended for establishing data links and message interpretation.
15197.
15198. Mode
15199. EIA Rules
15200. CCIR Rules
15201. Protocol
15202.
15203.
179. (ECE Board Problem, November 1999) A radio station in mobile service
intended to be used while in motion or during halts at unspecified points.

15204.
15205. Maritime radio station
15206. Land mobile station
15207. Mobile station
15208. Mobile earth station
15209.
15210.
180. (ECE Board Problem, April 1999) What is the advantage on the TV receiver
audio by employing FM audio and AM video on the television transmitter?
15211.
15212. FM receiver rejects static noise
15213. FM receiver is basically insensitive to amplitude modulation
15214. Fm receiver is basically insensitive to amplitude modulation
15215. FM receiver is clear over AM.
15216.
15217.
181. (ECE Board Problem, April 1999) What does the elastic store refereed to in
the time division multiplex system used in fiber optic?
15218.
15219. Amplifier
15220. Holding memory
15221. Reflector
15222. Timer
15223.
15224.
182. (ECE Board Problem, November 1999) What are the two general categories
of methods for generating emission F3E?
15225.
15226. The only way to produce an emission F3E signal is with a reactance
modulator on the oscillator.
15227. The only way to produce an emission F3E signal is with a balanced modulator on
the oscillator.
15228. The only way to produce an emission F3E signal is with a balanced modulator on
the audio amplifier.
15229. The only way to produce an emission F3E signal is with a reactance modulator on
the final amplifier.
15230.
15231.
15232.
15233.
183. (ECE Board Problem, November 2002) Pressure us measured in terms of
Pascal, microbar, or__________.
15234.
15235. Newtons
15236. Newtons per meter
15237. Newtons per meter squared
15238. Pascal per meter squared
15239.
15240.
184. (ECE Board Problem, April 1999) What is the function of the network layer
in the computer communications?

15241.
15242. Parity control
15243. Direction control
15244. Congestion control
15245. Error control
15246.
15247.
185. (ECE Board Problem, April 2000) Which of the following limits the top
speed of transmitting information in fiber optic?
15248.
15249. Noise
15250. Detector speed
15251. Time domain
15252. Refractor index
15253.
15254.
186. (ECE Board Problem, April 1999) A mobile telephone system which uses an
analogue cellular radio standard which was superseded by Advanced Mobile Phone System
in the U.S.
15255.
15256. TDMA
15257. IMTS
15258. CDMA
15259. D-AMPS
15260.
15261.
187. (ECE Board Problem, November 2000) Satellite that rotates around the earth
in a low altitude elliptical or circular pattern.
15262.
15263. Geosynchronous Satellite
15264. Prograde
15265. Nonsynchronous satellite
15266. Apogee
15267.
15268.
188. (ECE Board Problem, April 2000) One of the following processes or system
best describe an example of a pilot tone system normally use in commercial broadcast FM
stations.
15269.
15270. Time division
15271. Frequency division
15272. Stereo multiplex
15273. QSK
15274.
15275.
189. (ECE Board Problem, November 2000) What is the main reason why coaxial
cable is not used in microwave signal transmission?
15276.
15277. Wide bandwidth
15278. Number of repeaters
15279. Low impedance

15280. High attenuation
15281.
15282.
190. (ECE Board Problem, April 2000) Refers to a characteristic of a multimode
fiber optic.
15283.
15284. Cladding thickness is less than the radius of the core and diameter of the core
must be greater than the wavelength of the light to be carried.
15285. Cladding thickness is greater than the radius of the core and the diameter of the
core must be lesser than the wavelength of the light to be carried.
15286. Cladding thickness is less than the radius of the core and the diameter of the core
must be lesser than the wavelength of the light to be carried.
15287. Cladding thickness is greater than the radius of the core and the diameter of
the core must be much greater than the wavelength of the light to be carried.
15288.
191. (ECE Board Problem, April 2000) Two or more LAN linked together over
the wide geographical area.
15289.
15290. HAN
15291. WAN
15292. MAN
15293. RAN
15294.
15295.
192. (ECE Board Problem, April 2000) A process of sending data in computing
technology by asking each remote computer terminal one at a time if such computer terminal
has data to send.
15296.
15297. Selection
15298. Networking
15299. Polling
15300. Coding
15301.
15302.
193. (ECE Board Problem, November 1999) What is the primary purpose of an
RF amplifier in receiver?
15303.
15304. To vary the receiver image rejection by utilizing the AGC.
15305. To provide the most receiver gain.
15306. To develop the AGC voltage.
15307. To improve the receiver’s noise figure.
15308.
15309.
194. (ECE Board Problem, April 2000) Why are fiber optic cables considered less
expensive compared to coaxial cables in communication system?
15310.
15311. Coaxial is very expensive than fiber optic.
15312. Due to weight.
15313. Installation cost of coaxial.
15314. Use of less repeaters.
15315.

15316.
195. (ECE Board Problem, November 1999) Refers to as a linkage by wire, radio,
satellite or other means, of two or more telecommunications carrier or operators with one
another for the purpose of allowing or enabling the subscriber of one carrier or operator to
access or reach the subscribers of the other carrier or operator.
15317.
15318. Interconnection
15319. Toll patching
15320. Gateway
15321. Outside plant sharing
15322.
196. (ECE Board Problem, November 1999) In order to have an effective radio
antenna the design of its radiator must have a minimum length equivalent to________.
15323.
15324. Λ/10
15325. Λ/4
15326. Λ/14
15327. Λ/6
15328.
15329.
197. (ECE Board Problem, April 2000) Referred as the forward link channel of
the cellular duplex system.
15330.
15331. Cell to Cell
15332. Mobile to Mobile unit
15333. Mobile to Cell unit
15334. Cell to Mobile unit
15335.
15336.
198. (ECE Board Problem, November 2000) Method of a telecommunications
operation where transmission can be made simultaneously in both direction of a channel.
15337.
15338. Semi-duplex Operation
15339. Duplex Operation
15340. Half-duplex Operation
15341. Simplex Operation
15342.
15343.
15344.
199. (ECE Board Problem, April 2000) Which symbol in radio signal emission
designation is referred to type of modulation of the main carrier?
15345.
15346. Second
15347. Fourth
15348. Third
15349. First
15350.
15351.
200. (ECE Board Problem, November 2000) What type of emission is produced
when an amplitude-modulated transmitter is modulated by a facsimile signal?
A3F
F3

A3C
F3F
15352.
201. (ECE Board Problem, November 2000) A point in the satellite orbit known
to be the closest location to the surface of the earth.
Zenith
Perigee
Apogee
Azimuth
15353.
202. (ECE Board Problem, November 2000) Determine from the following the
common use of DSB in broadcast and telecommunication.
15354. Satellite Communication
15355. FM/TV Stereo
15356. Two-Way Communication
15357. Telephone System
15358.
203. (ECE Board Problem, November 2000) Determine the image frequency of a
broadcast band receiver using a 455 kHz IF tuned to 630kHz-DZMM.
15359. 1085 kHz
15360. 1530 kHz
15361. 1540 kHz
15362. 1715 kHz
15363.
15364.
15365.
15366.
204. (ECE Board Problem, November 2000) A phenomenon which causes the
speed of light rays propagation in the fiber material changes, as it passes through different
medium in the fiber.
15367. Bending
15368. Refraction
15369. Diffraction
15370. Reflection

15371.
205. (ECE Board Problem, November 1999) An electronic equipment used in the
radio communication to measure standing wave ratio.
15372. Radio meter
15373. Reflectometer
15374. Oscilloscope
15375. Wave Meter
15376.
15377.
206. (ECE Board Problem, November 2000) Referred as an effect of parasitic
elements in an antenna system.
Decrease its directivity
Makes the antenna omni directional
Makes the antenna isotropic
Increase its directivity
15378.
207. (ECE Board Problem, November 2000) Radio wave concentration in the
direction of the signal emitted by a directional antenna.
15379. Side lobe radiation
15380. Major lobe radiation
15381. Back lobe radiation
15382. Transmitted signal
15383.
15384.
208. (ECE Board Problem, November 2002) What is the main principle used by
ITU in determining the distribution of the orbit/ spectrum resources?
15385. Depending on the geographical boundary of a nation
15386. Efficient use and equitable access.
15387. Depending on a national sovereignty declaration
15388. Equal distribution
15389.

15390.
15391.
209. (ECE Board Problem, April 2000) What quarter-wave transformer will
match a 600Ω transmission line to an antenna whose value is 70 Ω?
15392. 205 Ω
15393. 502 Ω
15394. 600 Ω
15395. 75 Ω
15396.
210. (ECE Board Problem, November 1999) Let us consider a frequency range of
405.0125 MHz to 405.0875 MHz and a 25 kHz channeling plan, determine the center
frequency of the second channel from the lower limit.
15397. 405.050 MHz
15398. 405.0125 MHz
15399. 405.025 MHz
15400. 405.011 MHz
15401.
211. (ECE Board Problem, April 2000) What is the reason why 5/8-whip vertical
antenna is of advantage than quarter wave vertical whip antenna?
15402. Less interference
15403. Can handle high power signal
15404. More gain
15405. Flexible
15406.
212. (ECE Board Problem, April 1999) Why is it that almost all switching type
integrated data communication circuits are called digital?
15407. They are mostly on/off devices.
15408. They process digital information
15409. They are small type
15410. They are integrated circuits.
15411.
213. (ECE Board Problem, November 2000)Which of the following shall be
complied by an international ship pursuant to the global maritime distress and safety system

implemented last 1999?
15412. A facsimile
15413. A radio personnel
15414. A Morse code
15415. A radio telegraph operator
15416.
15417.
15418.
15419.
214. (ECE Board Problem, November 2000) Bit rate of a telecommunications
carrier T2.
15420. 7.312 Mb/s
15421. 7.318 Mb/s
15422. 6.511 Mb/s
15423. 6.312 Mb/s
15424.
215. (ECE Board Problem, November 2000) In propagation of radio signals
through an aerial at what angle does not magnetic field is positioned with reference to the
direction of propagation.
15425. 180
15426. 90
15427. 0
15428. 45
15429.
216. (ECE Board Problem, April 1999) What is the frequency separation between
the visual carrier and the upper limits of its total channel bandwidth of a monochrome TV
broadcast?
15430. 4.5 MHz
15431. 4.75 MHz
15432. 3.0 MHz

15433. 1.25 MHz
15434.
217. (ECE Board Problem, November 2000) In radio communications, the term
trap antenna is referred to in one of the following statements.
15435. Antenna with wide beam width
15436. Those antennas with high rejecting capability to interfering signals.
15437. Those antenna with long coverage in terms of distance
15438. Antenna which can be used on more than one band due to the use of parallel
LC networks.
15439.
218. (ECE Board Problem, April 1999) What is the range of an AM broadcast
frequency tolerance above or below its assigned frequency?
15440. 25kHz
15441. 20 Hz
15442. 60 kHz
15443. 120 kHz
15444.
219. (ECE Board Problem, April 2000) Which part of the housing system in ECE
code is a circular opening through the floor structure to allow the passage of cable and wire.
15445. Insert
15446. Sleeve
15447. Raceway
15448. Slot
15449.
220. (ECE Board Problem, April 2000) What is the length of a simple quarter
wave antenna using a VHF frequency of 150.55 MHz?
15450. 0.98 ft.
15451. 1.24 ft.
15452. 1.80 ft.
15453. 1.55 ft.
15454.
221. (ECE Board Problem, November 2000) In the study of acoustics, the
velocity of sound is dependent to one of the following.

15455. Temperature
15456. Loudness
15457. Source of sound
15458. Properties of the medium
15459.
222. (ECE Board Problem, April 1999) Which of the following is not considered
as one of the causes for the loss of signal power as light travels through a fiber optic?
15460. Scattering
15461. Intermodulation
15462. Fiber bending
15463. Absorption
15464.
223. (ECE Board Problem, November 1999) Referred to as a light source of fiber
optic, which supplies power level of 5 to 7 mW and having a narrow spectrum of emission.
15465. Injection laser diode
15466. Photodiode
15467. Light emitting diode
15468. Crystal diode
15469.
224. (ECE Board Problem, April 2000) A digital mobile telephone system, which
is called European derivative of Global System for Mobile Communication System operating
at a higher frequency band.
15470. E-TACS
15471. IMTS
15472. DCS-1800
15473. TACS
15474.
225. (ECE Board Problem, April 1999) Communication through the use of a
modem is transmission of__________ data information in ____________ medium.
15475. Analog, analog
15476. Analog, digital

15477. Digital, analog
15478. Digital, digital
15479.
226. (ECE Board Problem, November 1999) What type of emission is produced
when amplitude modulated transmitter is modulated by a television signal?
15480. A3F
15481. F3C
15482. F3F
15483. A3C
15484.
15485.
227. (ECE Board Problem, April 1999) A term, used in radio communication
defining the frequency band from the lowest to its highest limits, designed to be passed
through a component, system or a device with an acceptable attenuation.
15486. Allocated band
15487. Baseband
15488. Bandwidth
15489. Transmitted signal
15490.
228. (ECE Board Problem, April 2000) Which body in the present ITU structure
took the place of CCITT?
15491. ITU-R
15492. ITU-D
15493. ITU-T
15494. RAG
15495.
15496.
VLF?

229. (ECE Board Problem, November 2002) What is the frequency range of

15497. 10-10 kHz
15498. 30-300 kHz

15499. 300-3000 kHz
15500. 3-30 kHz
15501.

230. (ECE Board Problem, April 1999) What is a wave front?

15502. A voltage pulse in a conductor
15503. A current pulse in the conductor
15504. A voltage pulse across a resistor
15505. A fixed point in an electromagnetic wave
15506.
231. (ECE Board Problem, November 2000) How would you best describe an
example of a pilot tone system use in commercial frequency modulation broadcast radio
stations?
15507. Frequency simplex
15508. Time division
15509. Stereo multiplex
15510. QSK
15511.
15512.
232. (ECE Board Problem, April 1999) Kind of broadcasting system where
television programs are transmitted directly to home/user receivers via satellite, thus making
the reception cover not only individuals in their homes but other places as well.
15513. Pay TV
15514. Direct to Home TV
15515. Cable TV
15516. VHF TV
15517.
233. (ECE Board Problem, November 1999) In telecommunication, what do we
call the difference in the voltage level between a driver and a terminator?
15518. System gain
15519. Noise margin
15520. System loss

15521. Noise difference
15522.
234. (ECE Board Problem, April 2000) Why is parallel transfer method in data
transmission faster then serial?
15523. Wider channel bandwidth
15524. Bits are transferred simultaneously
15525. Bits are lighter in parallel
15526. Due to faster changes in symbol
15527.
235. (ECE Board Problem, November 2000) Radio frequency where waveguide is
not used extensively.
15528. 3,750 MHz
15529. 2,000 MHz
15530. 10,300 MHz
15531. 150 MHz
15532.
236. (ECE Board Problem, April 1999) One of the following central office
switching equipment resistance limit refers to the longest subscriber loop length.
15533. 1500Ω
15534. 300Ω
15535. 2000Ω
15536. 800Ω
15537.
237. (ECE Board Problem, November 1999) A particular area on the surface of
the earth where the boresight of a steerable satellite beam is intended to be pointed.
15538. Footprint area
15539. Contour boresight area
15540. Equivalent service area
15541. Effective boresight area
15542.
238. (ECE Board Problem, April 1999) Kind of information transfer in digital
communication where the bits comprising one character are sent in sequence one at a time.

15543. Parallel transmission
15544. Batch transmission
15545. Simplex transmission
15546. Serial transmission
15547.
239. (ECE Board Problem, November 1999) Which of the following antenna
where its beamwidth is determine by the dimension of its horn, lens or reflector?
15548. Whip antenna
15549. Aperiodic antenna
15550. Aperture antenna
15551. Long wire antenna
15552.
240. (ECE Board Problem, April 1999) In a transoceanic satellite conversation,
how much is the typical delay before a reply is heard?
15553. 200ms.
15554. 900ms.
15555. 50ms.
15556. 600ms.
15557.
241. (ECE Board Problem, November 2000)Position of the maritime ship main
antenna, when the radio watch is secured or when the ship is in electrical storm.
15558. AA
15559. Main Transmitter
15560. Grounded
15561. HF
15562.

242. (ECE Board Problem, April 1999) Best applies to an optical fiber core.

15563. The same refractive index with the cladding
15564. A higher refractive index than the cladding
15565. A lower refractive index than the cladding

15566. A lower refractive index than air
15567.
15568.
243. (ECE Board Problem, November 1999) What measure will help you adopt
on the antenna system of VHF or UHF mobile transceivers that has very low height antenna?
15569. Increase transmitter to antenna cable
15570. Use directional antenna
15571. Check grounding system
15572. Provide loading coil
15573.
244. (ECE Board Problem, April 1999)How do you account the effect of light
intensity on the refractive index of a fiber optic?
15574. Decrease
15575. Stable
15576. Increase
15577. Decrease by half
15578.
15579.
245. (ECE Board Problem, November 1999) Refers to major advantage in the
selection of a guided tube.
15580. Durability
15581. Low cost
15582. Accuracy
15583. High power
15584.
246. (ECE Board Problem, November 2000) This is the terminal where riser cable
pairs are terminated to serve a portion or an entire floor of a building.
15585. Floor terminal distribution area
15586. Raceway terminal
15587. Floor distribution terminal
15588. Riser terminal

15589.
247. (ECE Board Problem, November 1999) This referred to a condition in a
telephone network where the calling party cannot get connected to the party being called.
15590. Disconnection
15591. Open network
15592. Blocked call
15593. Loss call
15594.
248. (ECE Board Problem, April 2000) In data transmission technology, signals
such as voice or video are binary transmitted over a cable known as_________.
15595. Video signals
15596. Cable signals
15597. Baseband signals
15598. Audio signals
15599.
249. (ECE Board Problem, November 1999) In satellite communications where
satellite revolves in an orbit that forms a plane passing through the center of gravity of the
erath, this center is called___________.
15600. Geocenter
15601. Earth center
15602. Plane center
15603. Center of gravity
15604.
250. (ECE Board Problem, November 1999) In television, the color with the most
luminance is ________________.
15605. Blue
15606. Green
15607. Yellow
15608. Red
15609.
251. (ECE Board Problem, April 2000) What do you call the dissipated power
affecting the antenna efficiency caused by arching effect in high-powered transmitters?
15610. Dissipated power

15611. Antenna resistance
15612. Corona discharge
15613. Antenna loss
15614.
252. (ECE Board Problem, November 1999) What is the process in radio
communication where information or intelligence signal at a lower frequency is put unto
higher radio frequency for transmission to receiving station?
15615. Detection
15616. Mixing
15617. Modulation
15618. Demodulation
15619.
253. (ECE Board Problem, April 2000) An inductor that is inserted in an antenna
element or transmission line for the purpose of producing a resonant system at specific.
15620. Reflector
15621. Traps
15622. Loading coil
15623. Base loading
15624.
254. (ECE Board Problem, November 2000) Satellite orbit around the earth are
either, a) all are circular, b) all are elliptical, c) they are either circular or elliptical and d)
none of these three.
15625. D
15626. B
15627. C
15628. A
15629.
255. (ECE Board Problem, April 2002) What is the main reason why television
picture signal uses amplitude modulation, while voice is frequency modulated?
15630. Maintain the power signal at received end.
15631. Eliminate attenuation of both video and audio
15632. Maintain synchronized scanning between transmit and received video.

15633. To minimize interference between signals at received end
15634.
256. (ECE Board Problem, April 2002) Which of the following is referred to as a
disadvantage of using squelch circuit?
15635. Effect of AGC is reduced for strong signals.
15636. Receiver sensitivity is reduced for strong signals.
15637. Very weak signals might not be received.
15638. Receiver selectivity is reduced for strong signals.
15639.
257. (ECE Board Problem, November 2000) How does spatial isolation technique
in satellite communications avoid interference?
15640. Use of different polarity antennas.
15641. Use of different types of antenna.
15642. Employment of highly directional spot-beam
15643. Use of low gain antenna
15644.
258. (ECE Board Problem, November 2000) A parameter of light beam that do
not change quantity when it enters one medium from another.
15645. Intensity
15646. Penetration
15647. Frequency
15648. Wavelength
15649.
259. (ECE Board Problem, November 2000) How far is the visual carrier from the
aural in the monochrome television broadcast channel have?
15650. 1.5 MHz
15651. 3 MHz
15652. 4.5 MHz
15653. 1.25 MHz
15654.
260. (ECE Board Problem, November 2000) An order signed by former President
F. Ramos last March 1998 providing the national policy in the operation and use of
international satellite communication in the Philippines

15655. Executive Order 3846
15656. Executive Order 59
15657. Executive Order 456
15658. Executive Order 467
15659.
261. (ECE Board Problem, November 2000) Where does the Secretary General in
the organizational structure of present ITU report?
15660. WTSG
15661. TDAB
15662. WRC
15663. Council
15664.
262. (ECE Board Problem, November 2000) In wire communication system
using fiber optic, the packing fraction is related to one of the following statement when
referred to fiber optic bundle.
15665. Ratio of the total fiber radius, to the sum of the fiber optic bundle radius.
15666. Ratio of half of the total fiber radius, to the sum of the fiber optic bundle radius.
15667. Ratio of half-sectional area of the fiber optic bundle, to the cross-sectional area of
the core
15668. Ratio of the total cross-sectional area to the total cross-sectional area of the
fiber bundle
15669.
263. (ECE Board Problem, April 2000) Determine the local oscillator frequency
of a broadcast band receiver using a 455kHz IF and is tuned at 630kHz.
15670. 175 kHz
15671. 1085 kHz
15672. 280 kHz
15673. 1530 kHz
15674.
264. (ECE Board Problem, April 1999) One of the following is not a probable
cause of radiating spurious signal from basic transmitter.
15675. Harmonics

15676. Regulated supply
15677. Internal heating
15678. Parasitic
15679.
265. (ECE Board Problem, April 2000) What is the purpose of the two Yagi beam
antenna on a VHF TV receiver?
15680. Used to receiver VHF and UHF stations.
15681. For receiving low and high band stations.
15682. To increase selectivity
15683. To increase sensitivity on both hands.
15684.
15685.
266. (ECE Board Problem, November 2000) What is the noise that is develop in
the RF amplifier front end of a TV receiver, which is indicated by a white dot in the picture?
15686. Inter carrier
15687. Black
15688. Snow
15689. IF
15690.
occurs?

267. (ECE Board Problem, April 1999) Region in the atmosphere where ducting

15691. Ground region
15692. Stratosphere
15693. Ionosphere
15694. Troposphere
15695.
268. (ECE Board Problem, April 2000) Who issues an authority to install, operate,
and maintain a cable television or render a television service within a specified area in the
country?
15696. Department of Transportation and Communication.
15697. Board of Communication

15698. Congress of the Philippines
15699. National Telecommunications Communication
15700.
269. (ECE Board Problem, April 1999) What is the source of sidebands in
frequency modulation?
15701. Oscillator
15702. Baseband Frequency
15703. Mixer
15704. Carrier Harmonics
15705.
270. (ECE Board Problem, November 2000) Which of the very thin layers of the
tube’s front surface of the vidicon TV camera located at the middle layer and possess very
high resistance when dark, while it reduces greatly when struck by photons of light?
15706.

Transparent Conductive Film

15707.

Photoresistive Layer

15708.

Photo Inductive Lens

15709.

Photosensitive Layer

15710.
271. (ECE Board Problem, April 2000) One of the following refers to the standard
frequency band limits of AM broadcast band?
15711. 30-300 MHz
15712. 88-108 MHz
15713. 3-30 MHz
15714. 535-1605 kHz
15715.
272. (ECE Board Problem, November 2000)In a cable facilities for a building
communications service,________ is referred to as the physical cable within a building or
series of buildings which may include both main cable pairs and house cable pairs but not
station wiring cable?
15716. Entrance cable
15717. Floor distribution cable
15718. House cable

15719. Building cable
15720.
273. (ECE Board Problem, April 1999) What is the range of the lower sideband of
an amplitude modulated signal whose carrier is 1.5 MHz and the intelligence component is
50 Hz to 20 kHz?
15721. 1.550 MHz to 1.700 MHz
15722. 1,499.980 kHz to 2,520.00 kHz
15723. 1.48 MHz to 1.4995 MHz
15724. 1,500.980 kHz to 2,480.00 kHz
15725.
274. (ECE Board Problem, November 2000) A stage in cellular communications
where voice channel is assigned to link up a call connection after a mobile or network
originated a call.
15726. Call termination
15727. Call completion
15728. Call connection
15729. Call drops
15730.
275. (ECE Board Problem, April 1999) How many satellites does not the GPS
system consists?
15731. 12 satellites
15732. 3 satellites
15733. 24 satellites
15734. 60 satellites
15735.
276. (ECE Board Problem, April 2000) Ratio of radiation resistance to the total
resistance on an antenna?
15736. Antenna gain
15737. Antenna sensitivity
15738. Antenna efficiency
15739. Antenna ratio
15740.

277. (ECE Board Problem, November 2000) What is the frequency of an LED at

1.9eV?
15741.

645 GHz

15742.

459 GHz

15743.

458 THz

15744.

337 THz

15745.
278. (ECE Board Problem, April 1999) One of the characteristics of a fiber optic
used in order to carry light in several modes of propagation or to become a multimode fiber.
15746. Diameter of the core must be equal to the wavelength of the light to be carried.
15747. Diameter of the core must be very much greater than the wavelength of the
light to be carried.
15748. Diameter of the core must be very small compared to the wavelength of light to
be carried.
15749. Diameter of the core must be much half the wavelength of the light to be carried.
15750.
279. (ECE Board Problem, April 2000) One of the following is a communications
filter generally used in the transceiver of a single sideband generator.
15751. Low-pass filter
15752. Crystal filter
15753. Bandpass filter
15754. Mechanical filter
15755.
280. (ECE Board Problem, April 2000) In computer communications, the term
RS-232C is referred to as__________.
15756. Analog connection standard
15757. Serial interference standard
15758. Digital connection standard
15759. Parallel port standard
15760.
15761.

15762.
15763.
15764.
15765.
15766.
15767.
15768.
15769.
15770.
15771.
15772.
15773.
15774.
15775.
15776.
15777.
15778.

15779. MULTIPLE CHOICE QUESTIONS IN

15780. ELECTRONICS
SYSTEMS AND
TECHNOLOGIES
15781. By
15782. Melvin C. Arceo
15783.

15784.
15785.
15786.

15787.
ENCODED BY:
15788. ANDRADE, Caroline T.
15789. GARCIA, Virginia Nonna H.
15790. GIRAO, Edward Joseph D.
15791. LAQUI, Louise Ruelyn J.
15792. LORENZO, Luer Breech B.
15793. RIVERA, Billy Joe S.
15794. SAMONTE, Adrian A.
15795. SANTOLLO, Dan Alvin
15796.
15797.
15798.
15799.

15800. MULTIPLE CHOICE QUESTIONS IN

15801. BROADCAST
ENGINEERING
15802.

Electronics Systems and Technologies
15803. By
15804.

Melvin C. Arceo
15805.
15806.
15807.
15808.

15809.
15810.

15811. ENCODED BY:

15812. ANDRADE, Caroline T.
15813.
In stereophonic broadcast, the center frequency of each SCA subcarrier shall be
kept at all times within ____ Hz of the authorized frequency.
15814.
15815. 200
15816. 300
15817. 400
15818. 500
15819.
15820.
Sawtooth generator circuits produce the scanning raster, but the sync pulses are
needed for
15821.
15822. Linearity
15823. Timing
15824. Keystoning
15825. Line pairing
15826.
15827.
Which of the following camera tubes has minimum lag?
15828.
15829. Vidicon
15830. Plumbicon
15831. Saticon
15832. Iconoscope
15833.
15834.
The service area in standard AM broadcast is described as ____ if there is no
fading signal.
15835.
15836. Class A
15837. Secondary
15838. Class B
15839. Primary
15840.
15841.
The vertical field-scanning frequency is _____ Hz.
15842.
15843. 30
15844. 60
15845. 525
15846. 15,750
15847.
15848.
A 4.5-MHz signal which is equal to the difference between the picture and sound
RF carrier frequencies in a 6-MHz TV channel.
15849.
15850. Audio frequency
15851. Video frequency
15852. Intercarrier frequency
15853. Subcarrier frequency

15854.
15855.
A system where the modulated RF picture and sound carrier signals are
distributed in a cable network, instead of wireless system.
15856.
15857. CCTV
15858. MATV
15859. CATV
15860. SATV
15861.
15862.
A class A FM station is limited in antenna height of _____ feet above average
terrain.
15863.
15864. 1000
15865. 2000
15866. 4000
15867. 5000
15868.
15869.
What circuit in the TV receiver is used to develop the high voltage needed to
operate the picture tube?
15870.
15871. Low-voltage power supply
15872. Horizontal output
15873. Vertical output
15874. Sync separator
15875.
15876.
The modulated picture carrier wave includes the composite video signal as the
15877.
15878. Average carrier level
15879. Symmetric envelope of amplitude variations
15880. Lower sideband without the upper sideband
15881. Upper envelope without the lower envelope
15882.
15883.
With which emission type is the capture-effect more pronounced?
15884.
15885. CW
15886. FM
15887. SSB
15888. AM
15889.
15890.
The hue of color sync phase is
15891.
15892. Red
15893. Cyan
15894. Blue
15895. Yellow-green
15896.

15897.
How much is the equivalent internal resistance of the electron beam with a 1.2mA beam current at 25 kV?
15898.
15899. 48 nano ohms
15900. 30 ohms
15901. 20.8 mega ohms
15902. 15.6 kilo ohms
15903.
15904.
The difference between the picture and sound carrier frequencies for channel 3 is
____ MHz.
15905.
15906. 3.58
15907. 64.5
15908. 4.5
15909. 6.75
15910.
15911.
Refers to the deviation of the operating frequency of a crystal oscillator from its
nominal value due to temperature variations.
15912.
15913. Drift
15914. Flashover
15915. Frequency deviation
15916. Deviation ratio
15917.
15918.
It is the measure of how many picture elements can be reproduced
15919.
15920. Definition
15921. Resolution
15922. Detail
15923. Any of these
15924.
15925.
A 3.58-MHz subcarrier signal for color in television
15926.
15927. Hue signal
15928. Video signal
15929. Audio signal
15930. Chroma signal
15931.
15932.
A class D FM station shall have an authorized power not exceeding _____ watts.
15933.
15934. 20
15935. 15
15936. 10
15937. 5
15938.
15939.
Which of the following is not a benefit of cable TV?

15940.
15941. Lower-cost reception
15942. Greater stability
15943. Less noise, stronger signal
15944. Premium cable channels
15945.
15946.
The width of the vertical sync pulse in the Philippine TV system is
15947.
15948. 21H
15949. 3H
15950. H
15951. 0.5H
15952.
15953.
Term in communication which is referred, “ to send out in all direction “
15954.
15955. Announce
15956. Broadcast
15957. Transmit
15958. Media
15959.
15960.
The number of frames per second in the Philippine TV system is
15961.
15962. 60
15963. 262 ½
15964. 4.5
15965. 30
15966.
15967.
It means multiple outlines of edges to the right in the picture.
15968.
15969. Ghosting
15970. Ringing
15971. Fading
15972. Snowing
15973.
15974.
In the sawtooth waveform for linear scanning,
15975.
15976. The linear rise is for flyback
15977. The complete cycle includes trace and retrace
15978. The sharp reversal in amplitude produces trace
15979. The beam moves faster during trace and retrace
15980.
15981.
The purpose of pre-emphasis and de-emphasis in FM broadcasting is to :
15982.
15983. Increase the high frequency amplitude
15984. Improve the audio harmonic
15985. Decrease the low frequency amplitude

15986. Improve the S/N ratio
15987.
15988.
The part of the visible spectrum where camera pickup tubes have the greatest
output is
15989.
15990. Red
15991. Blue
15992. Yellow-green
15993. Infrared
15994.
15995.
The type of modulation of the sound carrier signal is ________.
15996.
15997. Pulse modulation
15998. Phase modulation
15999. Amplitude modulation
16000. Frequency modulation
16001.
16002.
A video or audio signal that can be used directly to reproduce the picture and
sound.
16003.
16004. Baseband signal
16005. Broadband signal
16006. Electromagnetic wave signal
16007. Modulated signal
16008.
16009.
Class B FM station should have an ERP not exceeding ____ kW.
16010.
16011. 50
16012. 40
16013. 30
16014. 20
16015.
16016.
What technique is used to permit hundreds of TV signals to share a common
cable?
16017.
16018. Frequency modulation
16019. Mixing
16020. Frequency division multiplexing
16021. Time division multiplexing
16022.
16023.
Another name for the horizontal retrace in a TV receiver is the
16024.
16025. Ringing
16026. Burst
16027. Damper
16028. Flyback

16029.
16030.
In the Philippine color television system, the intercarrier frequency, in MHz, is
16031.
16032. 3.58
16033. 3.579545
16034. 4.5
16035. 45.75
16036.
16037.
In channel 14 (470 to 476 MHz), the 3.58-MHz color signal is transmitted at
16038.
16039. 471.25 MHz
16040. 473.25 MHz
16041. 474.83 MHz
16042. 475.25 MHz
16043.
16044.
Interfaced scanning eliminates
16045.
16046. Snowing
16047. Flicker
16048. Distortion
16049. Fading
16050.
16051.
Beam alignment magnets for the camera tube are adjusted while rocking which
control?
16052.
16053. Optical focus
16054. Electrical focus
16055. Beam current
16056. Shading
16057.
16058.
What is the frequency discriminator?
16059.
16060. An FM generator
16061. A circuit for detecting FM
16062. A circuit for filtering two closely adjacent signals
16063. An automatic bandwidth circuit
16064.
16065.
A system used in television field operation to make on the spot video tape
recordings using portable TV cameras and VTRs.
16066.
16067. SNG
16068. ENG
16069. HAFC
16070. MATV
16071.
16072.
Class B FM station shall have an authorized transmitter power not exceeding

______ kW.
16073.
16074. 10
16075. 100
16076. 1000
16077. 10000
16078.
16079.
The total bandwidth of an NTSC TV signal is
16080.
16081. 3.58 MHz
16082. 4.5 MHz
16083. 6 MHz
16084. 10.7 MHz
16085.
16086.
Referred to the oscillator signal “leak through” from a property neutralized
amplifier such as a master oscillator power amplifier.
16087.
16088. Carrier
16089. Stray signal
16090. Back wave
16091. Loss wave
16092.
16093.
Interfacing is used in television to
16094.
16095. Produce the illusion of motion
16096. Ensure that all lines on the screen are scanned, not merely the alternate ones
16097. Simplify the vertical sync pulse train
16098. Avoid flicker
16099.
16100.
Coaxial cable for distribution system has an impedance of
16101.
16102. 50 ohms
16103. 75 ohms
16104. 150 ohms
16105. 300 ohms
16106.
16107.
The average voltage value of the 3.58-MHz modulated chrominance signal is
16108.
16109. Zero for most colors
16110. Close to black for yellow
16111. The brightness of the color
16112. The saturation of the color
16113.
16114.
When does broadcast station conduct an equipment test?
16115.
16116. During day time

16117. During night time
16118. During experimental period
16119. At any time
16120.
16121.
It causes the picture information to spread out or crowded at one end of the raster
compared to the opposite end.
16122.
16123. Linear scanning
16124. Interfaced scanning
16125. Non-linear scanning
16126. Retrace
16127.
16128.
If the camera cannot be placed far away enough to include everything in the
scene, change the lens to one with a
16129.
16130. Lower f rating
16131. Higher f rating
16132. Longer focal length
16133. Shorter focal length
16134.
16135.
Type of radio communication transmission utilizing frequency modulation
technique
16136.
16137. Television video
16138. Broadcasting in 535-1606 kHz
16139. Single sideband HF transmission
16140. Television audio
16141.
16142.
The amount of color in the picture or color intensity is the ______.
16143.
16144. Color level
16145. Chroma level
16146. Saturation
16147. Any of these
16148.
16149.
One of the early radio transmitters which produced keyed carrier generating purer
waveform than spark transmitter, used for high powered RF transmission and are limited
to radio frequency of about 500 kHz.
16150.
16151. Arc transmitter
16152. Hartley transmitter
16153. Spark transmitter
16154. Frequency transmitter
16155.
16156.
A technique where segments of videotape are joined by electronic erasing and
recording to create a single program.

16157.
16158. Masking
16159. Segmenting
16160. Editing
16161. Programming
16162.
16163.
A class C FM station has an authorized radiated power not exceeding ____watts
of ERP.
16164.
16165. 500
16166. 750
16167. 1000
16168. 2000
16169.
16170.
The assembly around the neck of a picture tube that produces the magnetic fields
that deflect and scan the electron beams is called the
16171.
16172. Shadow mask
16173. Phosphor
16174. Electron gun
16175. Yoke
16176.
16177.
An odd number of lines per frame forms part of every one of the world’s TV
systems. This is
16178.
16179. Done to assist interlace
16180. Purely an accident
16181. To ensure that line and frame frequencies can be obtained from the same original
source
16182. Done to minimize interference with the chroma subcarrier
16183.
16184.
The difference between the sound carrier and the color signal is
16185.
16186. 4.5 MHz
16187. 1.25 MHz
16188. 0.92 MHz
16189. 0.25 MHz
16190.
16191.
In color television, it is made for uniform color in the raster.
16192.
16193. Beam-landing adjustment
16194. Degaussing
16195. Internal blanking adjustment
16196. Background control
16197.
16198.
Which of the following camera tubes uses load oxide for the photoconductive

target plate?
16199.
16200. Vidicon
16201. Plumbicon
16202. Saticon
16203. Image orthicon
16204.
16205.
The number of fields is _____ per frame.
16206.
16207. 2
16208. 60
16209. 525
16210. 262 ½
16211.
16212.
An RF carrier wave that is frequency-modulated by the baseband audio signal in
TV broadcasting.
16213.
16214. Audio signal
16215. Video Signal
16216. Intercarrier signal
16217. Color signal
16218.
16219.
A class B FM station is limited in antenna height of _____ feet.
16220.
16221. 1000
16222. 500
16223. 250
16224. 100
16225.
16226.
The HV anode supply for the picture tube of a TV receiver is generated in the
16227.
16228. Mains transformer
16229. Vertical output stage
16230. Horizontal output stage
16231. Horizontal deflection oscillator
16232.
16233.
A tap for the subscriber drop line has a
16234.
16235. High insertion loss
16236. High tap loss
16237. Low tap loss
16238. 300-ohm
16239.
16240.
Which system can be used for both recording and playback?
16241.
16242. CED

16243. VHD
16244. Laser disk
16245. VHS
16246.
16247.
The hue 180 degrees out of phase with red is
16248.
16249. Cyan
16250. Yellow
16251. Green
16252. Blue
16253.
16254.
It is used around the phosphor dots to make a darker black which improves
contrast in the picture.
16255. Black masking
16256. Convergence adjustment
16257. Shadow masking
16258. Color purity adjustment
16259.
16260.
A lens lower f rating is ____ lens that allows more light input.
16261.
16262. Slower
16263. Wider
16264. Narrower
16265. Faster
16266.
16267.
Picture frames are repeated at the rate of ____ per second.
16268.
16269. 30
16270. 60
16271. 45
16272. 50
16273.
16274.
The effective radiated power of a class A FM station should not exceed _____
kW.
16275.
16276. 125
16277. 30
16278. 10
16279. 1
16280.
16281.
In television, 4:3 represents the
16282.
16283. Interface ratio
16284. Maximum horizontal deflection
16285. Aspect ratio
16286. Ratio of the two diagonals

16287.
16288.
Titling the video head gaps is necessary with the
16289.
16290. Color-under
16291. Zero guard bands
16292. FM luminance signal
16293. Long-play tapes
16294.
16295.
It is a special camera tube with a test pattern in the image plate.
16296.
16297. Vidicon
16298. Monoscope
16299. Oscilloscope
16300. Iconoscope
16301.
16302.
The number of lines scanned per frame in the raster on the picture tube screen is
16303.
16304. 525
16305. 262 ½
16306. 20
16307. 10
16308.
16309.
One of the following is a high powered RF ac basic transmitter that has two or
more stages, the oscillator stage which determines the frequency of operation and RF
amplifier stage or stages that develop the high power output. The purpose of which is to
develop a good frequency stability.
16310.
16311. MOPA
16312. Hartley
16313. Alexanderson
16314. Goldsmith
16315.
16316.
Camera signal output without sync is called ______.
16317.
16318. Black burst
16319. Generator lock video
16320. Composite video
16321. Non-composite video
16322.
16323.
The tint of the color is its
16324.
16325. Brightness
16326. Contrast
16327. Chroma
16328. Hue
16329.

16330.
Which frequency band is the standard AM radio broadcast?
16331.
16332. HF
16333. UHF
16334. MF
16335. VHF
16336.
16337.
The I and Q composite color signals are multiplexed onto the picture carrier by
modulating a 3.58 MHz subcarrier using
16338.
16339. FM
16340. PM
16341. DSB AM
16342. Vestigial sideband AM
16343.
16344.
The shadow mask in a color picture tube is used to
16345.
16346. Reduce X-ray emission
16347. Ensure that each beam hits only its own dots
16348. Increase screen brightness
16349. Provide degaussing for the screen
16350.
16351.
The video heads rotate at high velocity to increase the
16352.
16353. Tape speed
16354. Writing speed
16355. Reel rotation
16356. Tape tension
16357.
16358.
How ho you eliminate radio frequency variation of an oscillator transmitter
caused by its supply voltage?
16359.
16360. Use of regulated power supply
16361. Use of new power supply
16362. Use of high capacitor in the supply circuit
16363. Loosen power supply shielding
16364.
16365.
The composite video signal includes the camera signal with the following except
16366.
16367. Picture information
16368. Sync pulses
16369. Blanking pulses
16370. Camera signal
16371.
16372.
A lens has an 8-cm focal length and 4-cm diameter. Its f rating is
16373.

16374. 2
16375. 4
16376. 8
16377. 32
16378.
16379.
Which of the following is a possible cause for an abrupt frequency variation in a
self-excited transmitter oscillator circuits resulting a poor frequency stability to hold a
constant frequency oscillation?
16380.
16381. DC and RF AC heating of resistor which cause a change in values
16382. Heating and expansion of oscillator coil
16383. Heating of capacitor in the oscillator
16384. Power supply voltage changes
16385.
16386.
How long does it take to scan 2 picture elements when 400 are scanned in 50
microseconds?
16387.
16388. 25 microsec
16389. 0.25 microsec
16390. 2.5 microsec
16391. 0.5 microsec
16392.
16393.
Anode voltage for the picture tube, developed from the output of the horizontal
deflection circuit.
16394.
16395. Yoke voltage
16396. Flyback voltage
16397. Aquadag voltage
16398. Tube voltage
16399.
16400.
The channel spacing in the Philippine FM broadcast standards
16401.
16402. 400 kHz
16403. 800 kHz
16404. 600 kHz
16405. 200 kHz
16406.
16407.
What is the black-and-white or monochrome brightness signal in TV called?
16408.
16409. RGB
16410. Color subcarrier
16411. Q and I
16412. Luminance Y
16413.
16414.
Which of the following is a midband cable TV channel?
16415.

16416. 6
16417. 7
16418. 14
16419. 23
16420.
16421.
What is the primary purpose of an RF amplifier in a receiver?
16422.
16423. To vary the receiver image rejection by utilizing the AGC
16424. To provide most of the receiver gain
16425. To develop the AGC voltage
16426. To improve the receiver’s noise figure
16427.
16428.
The color with the most luminance is
16429.
16430. Red
16431. Yellow
16432. Green
16433. Blue
16434.
16435.
It is the light flux intercepted by one-foot-square surface that is one foot from
one-candlepower source.
16436.
16437. Candela
16438. Footcandle
16439. Lux
16440. Lumens
16441.
16442.
Refers to the possible cause for an abrupt frequency variations in a self-excited
transmitter oscillator circuit resulting to a poor frequency stability to hold a constant
oscillator.
16443.
16444. Poor soldered connections
16445. Heating of capacitor in the oscillator
16446. DC and AC heating of resistors which cause change in values
16447. Aging which cause change in condition in parts characteristics
16448.
16449.
It is the difference in intensity between the black parts and white parts of the
picture.
16450.
16451. Brightness
16452. Hue
16453. Contrast
16454. Illumination
16455.
16456.
The stereophonic subcarrier suppression level in the Philippines standards
16457.

16458. Less than 4% modulation of the main carrier
16459. Less than 3% modulation of the main carrier
16460. Less than 2% modulation of the main carrier
16461. Less than 1% modulation of the main carrier
16462.
16463.
The sound IF in a TV receiver is
16464.
16465. 4.5 MHz
16466. 10.7 MHz
16467. 41.25 MHz
16468. 45.75 MHz
16469.
16470.
The circuit separates sync pulse from the composite video waveform is
16471.
16472. The keyed AGC amplifier
16473. A clipper
16474. An integrator
16475. A differentiator
16476.
16477.
In the CED system, the disk capacitance varies with the
16478.
16479. Pit depth
16480. Disk size
16481. Speed of rotation
16482. Wavelength of the scanning light
16483.
16484.
The final power amplifier in an FM transmitter usually operates class _____
16485.
16486. AB
16487. C
16488. B
16489. A
16490.
16491.
In a picture tube, it is the total angle that the beam can be deflected without
touching the sides of the envelope.
16492.
16493. Screen angle
16494. Tube angle
16495. Picture angle
16496. Deflection angle
16497.
16498.
It is necessary to time the scanning with respect to picture information.
16499.
16500. Flyback
16501. Synchronization
16502. Blanking

16503. Scanning
16504.
16505.
The intermediate frequency used in for FM broadcasting Philippine standards.
16506.
16507. 455 kHz
16508. 10.7 MHz
16509. 11.4 MHz
16510. 12.5 MHz
16511.
16512.
What is the horizontal scanning time for 20 pixels?
16513.
16514. 2.5 microsec
16515. 0.25 microsec
16516. 1.25 microsec
16517. 125 microsec
16518.
16519.
In basic radio transmitter, the main advantage of a single-tube transmitter is
16520.
16521. Frequency instability
16522. Non-portable
16523. Heating effect
16524. Bulky
16525.
16526.
The carrier transmitted 1.25 MHz above the bottom frequency in a Philippine TV
channel is the
16527.
16528. Sound carrier
16529. Chroma carrier
16530. Intercarrier
16531. Picture carrier
16532.
16533.
In camera tubes, it means that the old image remains too long after the picture
information on the target plate has changed.
16534.
16535. Light lag
16536. Switch lag
16537. Image lag
16538. Camera lag
16539.
16540.
What is the maximum color TV bandwidth?
16541.
16542. 1.6 MHz
16543. 0.5 MHz
16544. 1.0 MHz
16545. 1.3 MHz
16546.

16547.
Class of FM station where its authorized power should not exceed 15 kW.
16548.
16549. Class A
16550. Class B
16551. Class C
16552. Class D
16553.
16554.
What is the name of the solid state imaging device used in TV cameras that
converts the light in a scene into an electrical signal?
16555.
16556. CCD
16557. Phototube matrix
16558. Vidicon
16559. MOSFET array
16560.
16561.
The signals sent by the transmitter to ensure correct scanning in the receiver is
called
16562.
16563. Sync
16564. Chroma
16565. Luminance
16566. Video
16567.
16568.
What signals are transmitted by a SSBSC transmitter when no modulating signal
is present?
16569.
16570. The upper sideband only
16571. Both the upper and lower sideband
16572. The lower sideband
16573. No signal transmitted
16574.
16575.
The second IF value for color in receivers, for any station, is
16576.
16577. 0.5 MHz
16578. 1.3 MHz
16579. 3.58 MHz
16580. 4.5 MHz
16581.
16582.
In the frame for which interfaced scanning is used, alternate lines are skipped
during vertical scanning because
16583.
16584. The trace is slower than retrace
16585. The vertical scanning frequency is doubled from 30 to 60 Hz
16586. The horizontal scanning is slower than vertical scanning
16587. The frame has a 4:3 aspect ratio
16588.

16589.
A typical value of vidicon dark current is
16590.
16591. 0.2 microampere
16592. About 200 microampere
16593. 8 milliampere
16594. 800 milliampere
16595.
16596.
The smallest are of light or shade in the image is a picture element called
16597.
16598. Chroma
16599. Hue
16600. Contrast
16601. Pixel
16602.
16603.
An entry of the time the station begins to supply power to the antenna and the
time it stops.
16604.
16605. Operating log entries
16606. Program log entries
16607. Operating schedule
16608. Any of these
16609.
16610.
What type of circuit is used to modulate and demodulate the color signals?
16611.
16612. Phase-locked loop
16613. Differential peak detector
16614. Quadrature detector
16615. Balanced modulator
16616.
16617.
This is referred to as a fixed radio station that broadcast program material from
audio to transmitter by radio link.
16618.
16619. Aural BC intercity relay
16620. Aural broadcast STL
16621. Short wave station
16622. Remove pick-up
16623.
16624.
Indicate which of the following frequencies will not be found in the output of a
normal TV receiver tuner.
16625.
16626. 4.5 MHz
16627. 41.25 MHz
16628. 45.75 MHz
16629. 42.17 MHz
16630.
16631.
In all standard television broadcast channels , the difference between the picture

and sound carrier frequencies is
16632.
16633. 0.25 MHz
16634. 1.25 MHz
16635. 4.5 MHz
16636. 6 MHz
16637.
16638.
It is caused by phase distortion for video frequencies of about 100 kHz and lower.
16639.
16640. Streaking
16641. Snowing
16642. Ringing
16643. Fading
16644.
16645.
Special effects and production switching are done by the
16646.
16647. CCU
16648. ENG camera
16649. SEG
16650. Sync generator
16651.
16652.
A picture has 400 horizontal and 300 vertical picture elements. What is the total
number of details in the picture?
16653.
16654. 120,000
16655. 700
16656. 0.75
16657. 100
16658.
16659.
After the IF stages have been aligned, the next stage to align in FM receiver is
16660.
16661. Local oscillator
16662. Limiter stage
16663. RF amplifier
16664. Mixer stage
16665.
16666.
What ensures proper color synchronization at the receiver?
16667.
16668. Sync pulses
16669. Quadrature modulation
16670. 4.5-MHz intercarrier sound
16671. 3.58-MHz color burst
16672.
16673.
The interfering beat frequency of 920 kHz is between the 3.58-MHz color
subcarrier and the
16674.

16675. 4.5-MHz intercarrier sound
16676. Picture carrier
16677. Lower adjacent sound
16678. Upper adjacent picture
16679.
16680.
Light is converted to video signal by the _____ tube.
16681.
16682. Camera tube
16683. Picture tube
16684. Anode tube
16685. Cathode tube
16686.
16687.
The frequency spectrum of the stereophonic FM signal.
16688.
16689. 67 kHz
16690. 59.5 to 74.5 kHz
16691. 19 to 38 kHz
16692. 30 to 53 kHz
16693.
16694.
Equalizing pulses in TV are sent during
16695.
16696. Horizontal blanking
16697. Vertical blanking
16698. The serrations
16699. The horizontal retrace
16700.
16701.
Which signal has color information for 1.3 MHz bandwidth?
16702.
16703. I
16704. Y
16705. R-Y
16706. B-Y
16707.
16708.
It is the distance from the center of the lens of the camera to the point at which
parallel rays from a distant object come to a common focal point.
16709.
16710. Focal length
16711. Latus rectum
16712. Major axis
16713. Minor axis
16714.
16715.
The method of generating FM used by broadcast station is
16716.
16717. Direct
16718. Indirect
16719. Insertion

16720. All of these
16721.
16722.
The picture and sound carrier frequencies in a TV receiver IF are respectively.
16723.
16724.
41.25 and 45.75 MHz
16725.
45.75 and 41.25 MHz
16726.
41.75 and 45.25 MHz
16727.
45.25 and 41.75 MHz
16728.
16729.
The channel width in the Philippine TV system, in MHz, is
16730.
16731. 41.25
16732. 6
16733. 4.5
16734. 3.58
16735.
16736.
The cable converter output or the TV receiver is usually on channel
16737.
16738. 3
16739. 6
16740. 7
16741. 9
16742.
16743.
One-half line spacing between the start positions for scanning even and odd fields
produces
16744.
16745. Linear scanning
16746. Line pairing
16747. Fishtailing
16748. Exact interlacing
16749.
16750.
Precise scanning size and linearity are most important in
16751.
16752. A black-and-white camera
16753. Plumbicon
16754. A single-tube color pickup
16755. A saticon
16756.
16757.
A signal in which the sum of all signals which frequency-modulates the main
carrier.
16758.
16759. Composite baseband signal
16760. FM baseband
16761. Main channel signal
16762. Stereophonic signal
16763.

16764.
What is the total number of interlaced scan lines in one complete frame of a
NTSC Philippine TV signal?
16765.
16766. 262 ½
16767. 525
16768. 480
16769. 625
16770.
16771.
The video voltage applied to the picture tube of a television receiver is fed in
16772.
16773. Between grid and ground
16774. To the yoke
16775. To the anode
16776. Between the grid and cathode
16777.
16778.
How many dBmV units correspond to a 1-mV signal level?
16779.
16780. 0
16781. 1
16782. 3
16783. 6
16784.
16785.
In color television, it is made to maintain neutral white from low to high levels of
brightness.
16786.
16787. Internal color adjustment
16788. Color-temperature adjustments
16789. Shadow masking
16790. Convergence adjustment
16791.
16792.
Average power of a radio transmitter supplied to the antenna transmission line by
a transmitter during one radio frequency cycle taken under the condition or no
modulation.
16793.
16794. Peak envelope power
16795. Rated power
16796. Carrier power
16797. Mean power
16798.
16799.
The number of scanning lines is ____ per second.
16800.
16801. 525
16802. 262 ½
16803. 15,750
16804. 30
16805.

16806.
The ratio of the actual frequency swing to the frequency swing defined as 100
percent modulation, expressed in percentage.
16807.
16808. Modulation index
16809. Deviation ration
16810. Maximum deviation
16811. Percentage modulation
16812.
16813.
In a TV receiver, the color killer
16814.
16815. Cuts off the chroma stages during monochrome reception
16816. Ensures that no color is transmitted to monochrome receivers
16817. Prevents color coding
16818. Make sure that the color burst is not mistaken for sync pulses, by cutting off
reception during the back porch.
16819.
16820.
How many TV fields are recorded on one slant track of tape?
16821.
16822. 1
16823. 2
16824. 4
16825. 60
16826.
16827.
A communication circuit using class C amplifier is considered a narrow band
amplifier if the bandwidth is less than _____ % of its resonant frequency.
16828.
16829. 15
16830. 13
16831. 10
16832. 20
16833.
16834.
The width of a vertical sync pulse with its serrations includes the time of
16835.
16836. Six half-lines, or three lines
16837. Five lines
16838. Three half-lines
16839. Five half-lines
16840.
16841.
A low-contrast picture in which white seems flat and lacking in detail suggests
16842.
16843. Low beam current
16844. High gain in the pre-amplifier
16845. Excessive gamma
16846. Insufficient scanning width
16847.
16848.
The product of the transmitter power multiplied by the antenna power gain of the

antenna field gain squared.
16849.
16850. Field intensity
16851. Field gain
16852. ERP
16853. Electric field strength
16854.
16855.
What keeps the scanning process at the receiver in step with the scanning in the
picture tube at the receiver?
16856.
16857. Nothing
16858. Sync pulses
16859. Color burst
16860. Deflection oscillators
16861.
16862.
The number of lines per second in the TV system is
16863.
16864. 31,500
16865. 15,700
16866. 262 ½
16867. 525
16868.
16869.
In a basic transmitter, ________is a kind of transmitter that develops type B
emission.
16870.
16871. Arc
16872. Spark
16873. Alexanderson
16874. High end
16875.
16876.
It is a number that indicates how contrast is expanded or compressed.
16877.
16878. Alpha
16879. Beta
16880. Gamma
16881. Sigma
16882.
16883.
Color picture tubes have ______ guns for its phosphors.
16884.
16885. 1
16886. 2
16887. 3
16888. 4
16889.
16890.
The FM broadcast band is divided into _____ channels are suggested by KBP.
16891.

16892. 200
16893. 100
16894. 50
16895. 25
16896.
16897.
The output of the vertical amplifier, applied to the yoke in a TV receiver, consists
of
16898.
16899. Direct current
16900. Amplified vertical sync pulse
16901. A sawtooth voltage
16902. A sawtooth current
16903.
16904.
The frequency spectrum of the stereophonic FM signal.
16905.
16906. 67 kHz
16907. 59.5 kHz to 74.5 kHz
16908. 19 kHz to 38 kHz
16909. 30 kHz to 53 kHz
16910.
16911.
What is the video frequency response corresponding to the horizontal resolution
of 200 lines?
16912.
16913. 4 MHz
16914. 1.5 MHz
16915. 4.5 MHz
16916. 2.5 MHz
16917.
16918.
The gamma of the picture tube is
16919.
16920. 0.4545
16921. 1.0
16922. 1.4
16923. 2.2
16924.
16925.
It is the instantaneous departure of the frequency of the emitted wave from the
center frequency resulting from modulation.
16926.
16927. Deviation
16928. Frequency swing
16929. Phase shift
16930. Deviation ratio
16931.
16932.
If a TV sound transmitter has a carrier frequency of 197.75 MHz, the picture
carrier is
16933.

16934. 191.75 MHz
16935. 193.25 MHz
16936. 202.25 MHz
16937. 203.75 MHz
16938.
16939.
The number of lines per field in the Philippine TV system is
16940.
16941. 262 ½
16942. 525
16943. 30
16944. 60
16945.
16946.
What is the best site of an AM broadcast transmitter?
16947.
16948. Marshy land
16949. Dry land
16950. Highly elevated
16951. Average terrain
16952.
16953.
What is the hue of a color 90 degrees leading sync burst phase?
16954.
16955. Yellow
16956. Cyan
16957. Blue
16958. Orange
16959.
16960.
The two black conductive coatings of picture tubes are made up of
16961.
16962. Phosphor
16963. Aquadag
16964. Cavity
16965. Nickel
16966.
16967.
The maximum power allocation of AM transmitter in Metro Manila in kW is
16968.
16969. 10 kW
16970. 20 kW
16971. 40 kW
16972. 30 kW
16973.
16974.
The function of the serrations in the composite video waveforms is to
16975.
16976. Equalize the change in the integrator before the start of vertical retrace
16977. Help vertical synchronization
16978. Help horizontal synchronization
16979. Simplify the generation of the vertical sync pulse

16980.
16981.
Which system uses a light beam for playback?
16982.
16983. CED
16984. VHD
16985. Betamax
16986. VLP
16987.
16988.
Weak emission from one cathode in a tricolor picture tube causes
16989.
16990. A weak picture
16991. A long warmup time
16992. A color imbalance in the raster and picture
16993. All of these
16994.
16995.
In AM broadcast, the current carrier shift at any percentage of modulation shall
not exceed
16996.
16997. 5%
16998. 15%
16999. 20%
17000. 2.5%
17001.
17002.
Indicate which voltages are not found in the output of a normal monochrome
receiver video detector.
17003.
17004. Sync
17005. Video
17006. Sweep
17007. Sound
17008.
17009.
The sawtooth waveform for deflection provides _______.
17010.
17011. Horizontal deflection
17012. Distortions
17013. Linear scanning
17014. Flicker
17015.
17016.
In AM broadcast, the transmitter must be capable of maintaining the operating
frequency within the limits of ______.
17017.
17018. +/- 10 Hz
17019. +/- 20 Hz
17020. +/- 25 Hz
17021. +/- 75 Hz
17022.

17023.
How much illumination in lux a 400-candlepower make that is 3 meters from the
surface?
17024.
17025. 133.3
17026. 1200
17027. 200
17028. 44.4
17029.
17030.
Brightness variations of the picture information are in which signal?
17031.
17032. I
17033. Q
17034. Y
17035. R-Y
17036.
17037.
How many octaves is the frequency range of 1 to 8 MHz?
17038.
17039. 1
17040. 2
17041. 3
17042. 8
17043.
17044.
For television, the maximum deviation of the FM sound signal in kHz.
17045.
17046. 10
17047. 25
17048. 75
17049. 100
17050.
17051.
Indicate which of the following signals is not transmitted in color TV
17052.
17053. Y
17054. Q
17055. R
17056. I
17057.
17058.
Emission outside of the assigned channel, as a result of the modulation process.
17059.
17060. Overmodulation
17061. Spurious emission
17062. Out-of-band emission
17063. In band emission
17064.
17065.
Determine which of the following is not part of RF section of a radio transmitter.
17066.
17067. Master oscillator

17068. Buffer amplifier
17069. AF voltage amplifier
17070. Frequency amplifier
17071.
17072.
The power of any conducted spurious emission shall be attenuated below the
maximum level of carrier frequency in accordance with the following formula:
17073.
17074. Attenuation (dB) = 43 + 20 log P
17075. Attenuation (dB) = 43 + log P
17076. Attenuation (dB) = 43 + 10 log P
17077. Attenuation (dB) = 43 + log P/10
17078.
17079.
In television, gamma affects _____
17080.
17081. Color
17082. Contrast
17083. Brightness
17084. Hue
17085.
17086.
In the IRE scale for the composite video signal, what is the number of IRE units
for sync?
17087.
17088. 7.5
17089. 92.5
17090. 40
17091. 10
17092.
17093.
As prescribed by the technical standards for Cable Television operation and in
order to be compatible for any value added services in the future, Trunk cable should
have a minimum diameter of _______.
17094.
17095. 0.25 inch
17096. 0.5 inch
17097. 0.75 inch
17098. 1.0 inch
17099.
17100.
Compared with 100 percent saturation, the desaturated color have
17101.
17102. More luminance for the Y signal
17103. Less luminance for the Y signal
17104. More chrominance for the C signal
17105. Less hue for the C signal
17106.
17107.
What is the practical baseband frequency for the color video signal?
17108.
17109. 1 MHz

17110. 2 MHz
17111. 0.2 MHz
17112. 0.5 MHz
17113.
17114.
What is the diagonal screen size for the 19CP4 picture tube?
17115.
17116. 21
17117. 23
17118. 4
17119. 19
17120.
17121.
What is the phase angle between B – Y and R – Y?
17122.
17123. 180 deg
17124. 45 deg
17125. 90 deg
17126. 270 deg
17127.
17128.
How many gray scale steps are in the EIA test pattern in television?
17129.
17130. 10
17131. 40
17132. 50
17133. 15
17134.
17135.
In TV, degaussing is done with _____.
17136.
17137. Direct current
17138. Pulsed current
17139. Alternating current
17140. Any of these
17141.
17142.
R, G and B video drive controls set for ________.
17143.
17144. Black
17145. Dark gray
17146. White
17147. Light gray
17148.
17149.
What is the phase difference between the color sync burst and the B – Y video?
17150.
17151. 180 deg
17152. 45 deg
17153. 90 deg
17154. 270 deg
17155.

17156.
What is the hue of the color sync burst?
17157.
17158. Yellow-green
17159. Red
17160. Blue
17161. Orange
17162.
17163.
What synchronizes the horizontal of the TV picture tube?
17164.
17165. HSC
17166. HAFC
17167. HFC
17168. HAC
17169.
17170.
What is the typical anode voltage for a 25-inch color picture tube?
17171.
17172. 3 kV
17173. 20 kV
17174. 10 kV
17175. 30 kV
17176.
17177.
In television, what is the phosphor number for monochrome picture tube?
17178.
17179. P4
17180. P21
17181. P22
17182. P3
17183.
17184.
In television picture tube, what is the color of the P1 phosphor?
17185.
17186. Red
17187. Green
17188. Yellow
17189. Blue
17190.
17191.
What video frequency corresponds to 240 lines of horizontal resolution?
17192.
17193. 1 MHz
17194. 3 MHz
17195. 2 MHz
17196. 4 MHz
17197.
17198.
The minimum FM broadcast transmitter power in metro manila and metro cebu is
17199.
17200. 25 kW
17201. 10 kW

17202. 1 kW
17203. 30 kW
17204.
17205.
The maximum power suggested by KBP on 919-1312 AM broadcast station in
Metro Manila.
17206.
17207. 10 kW
17208. 20 kW
17209. 15 kW
17210. 5 kW
17211.
17212.
What are the frequency limits of the standard AM broadcast band?
17213.
17214. 565 to 1605 kHz
17215. 535 to 1605 kHz
17216. 575 to 1615 kHz
17217. 535 to 1615 kHz
17218.
17219.
What is the width of an AM broadcast channel?
17220.
17221. 30 kHz
17222. 25 kHz
17223. 15 kHz
17224. 200 kHz
17225.
17226.
The following are designations of service areas of AM broadcast station, except:
17227.
17228. Primary
17229. Secondary
17230. Tertiary
17231. Intermittent
17232.
17233.
The following are parts of the AM broadcast day, except:
17234.
17235. Daytime
17236. Night time
17237. Mid-day
17238. Experimental period
17239.
17240.
Why is it desirable to have broadcast antennas on marshy land?
17241.
17242. For better reflection
17243. For ground wave radiation
17244. For greater absorption
17245. For sky wave propagation
17246.

17247.
What is another name for a console pot?
17248.
17249. Attenuator
17250. Gain control
17251. Fader
17252. Any of these
17253.
17254.
The highest peaks of modulation in AM should be held between what two
percentages?
17255.
17256. 85-100%
17257. 65-70%
17258. 50-75%
17259. 75-90%
17260.
17261.
What is the name of the second transmitter used when a station operates 24 hours
a day?
17262.
17263. Alternate
17264. Reserve
17265. Spare
17266. Diversity
17267.
17268.
What is a combo operator?
17269.
17270. Announcer
17271. Disk jockey
17272. Engineer
17273. All of these
17274.
17275.
What term is used to indicate intercom operation in a broadcast station?
17276.
17277. Communication
17278. Talk-back
17279. Respond
17280. Remote talk
17281.
17282.
What does a red light glowing in a studio indicate?
17283.
17284. Off the air
17285. Floating
17286. Experimental
17287. On the air
17288.
17289.
What is the attenuator which controls the the output of the program amplifier
called?

17290.
17291. Master gain control
17292. Auxiliary gain control
17293. Reserve frequency control
17294. Auxiliary frequency control
17295.
17296.
The following are important operational requirements during a broadcast, except:
17297.
17298. Timing
17299. Modulation
17300. Fidelity
17301. AF amplitude
17302.
What are the names of two unbalanced pads used in broadcasting?
17303.
17304. T and L
17305. K and P
17306. R and I
17307. H and L
17308.
17309.
What is the advantage of using balanced lines in audio systems?
17310.
17311. Receive balanced sound
17312. Improve fidelity
17313. Reduce noise pickup
17314. Improve carrier level
17315.
17316.
What is the advantage of using T-pad attenuators over potentiometers?
17317.
17318. Better energy conversion
17319. Better attenuation
17320. Match impedance better
17321. Any of these
17322.
17323.
What device is used to make up for the high-frequency losses in long AF lines?
17324.
17325. Signal booster
17326. Noise suppressor
17327. Line equalizer
17328. Compander
17329.
17330.
What is another term meaning “operating power”
17331.
17332. Licensed power
17333. Sideband power
17334. Audio power
17335. Harmonic power

17336.
17337.
What does maximum rated carrier power referred to?
17338.
17339. Buffer amplifier power rating
17340. Intermediate amplifier power rating
17341. Speech amplifier power rating
17342. Final-amplifier power rating
17343.
17344.
When are equipment tests made?
17345.
17346. Mid-day
17347. Daytime
17348. Night time
17349. Experimental period
17350.
17351.
What is the maximum allowable distortion at 80% modulation?
17352.
17353. 3%
17354. 4%
17355. 5%
17356. 6%
17357.
17358.
On what are proof-of-performance tests in broadcasting made?
17359.
17360. Omnidirectional antennas
17361. Directive antennas
17362. High gain antennas
17363. Any of these
17364.
17365.
Within what limits must the antenna current ratios of a directional antenna be
held?
17366.
17367. 3%
17368. 5%
17369. 4%
17370. 1%
17371.
17372.
What monitor is required at the operating position in a broadcast station?
17373.
17374. Frequency
17375. Modulation
17376. Fidelity
17377. Carrier
17378.
17379.
What monitor may also give an indication of carrier amplitude regulation?
17380.

17381. Modulation
17382. Carrier
17383. Fidelity
17384. Frequency
17385.
17386.
What device can give the most accurate instantaneous peak-of-modulation
indications?
17387.
17388. Spectrum analyzer
17389. Fourier analyzer
17390. CRT oscilloscope
17391. Frequency probe
17392.
17393.
The item required in program log?
17394.
17395. Identification
17396. Program description
17397. Sponsors and network name
17398. All of these
17399.
17400.
The item required in an operating log?
17401.
17402. Antenna power and programs on-off
17403. EBS tests
17404. Any of these
17405. Antenna lights and meter readings
17406.
17407.
The item required in a maintenance log?
17408.
17409. Any of these
17410. Antenna current checks
17411. Meter replacements
17412. Light inspection and experimental period operation
17413.
17414.
What is the minimum time broadcast station logs must be held?
17415.
17416. One year
17417. Two years
17418. Three years
17419. Five years
17420.
17421.
What class operator has no restrictions on technical work in a broadcast station?
17422.
17423. 1st phone
17424. 2nd phone
17425. 3rd phone

17426. 4th phone
17427.
17428.
What classes of operators are restricted on technical work in a broadcast station?
17429.
17430. 3rd phone
17431. 2nd phone
17432. 4th phone
17433. 2nd and 3rd phone
17434.
17435.
If improper transmitter indications are given at the remote-control point, what
should be done?
17436.
17437. First phone operator to transmitter
17438. Second phone operator to transmitter
17439. Third phone operator to transmitter
17440. Fourth phone to transmitter
17441.
17442.
How often must IDs be made in a broadcast station?
17443.
17444. Quarter of an hour
17445. Half an hour
17446. On the hour
17447. On the day
17448.
17449.
Where must station license be posted?
17450.
17451. Tower
17452. Modulators
17453. Transmitter
17454. Receiver
17455.
17456.
Where operator licenses must be posted?
17457.
17458. Operating desk
17459. Operating position
17460. Operating console
17461. Anywhere
17462.
17463.
What device is usually used today to measure the frequency of a broadcast
station?
17464.
17465. Multivibrators
17466. Counter
17467. Ripper
17468. Wave meter
17469.

17470.
What does EBS stand for?
17471.
17472. Electronic Broadcast System
17473. Emergency Broadcast System
17474. Electronic Base Station
17475. Emergency Base Station
17476.
17477.
How often must EBS tests be made?
17478.
17479. Weekly
17480. Daily
17481. Monthly
17482. Yearly
17483.
17484.
What must non-EBS station have?
17485.
17486. EBS signal monitor
17487. EAN signal monitor
17488. EAT signal monitor
17489. CPCS signal monitor
17490.
17491.
What stylus material is used in broadcast station?
17492.
17493. Ruby
17494. Gamet
17495. Emerald
17496. Diamond
17497.
17498.
What advantage is there to having heavy turntables?
17499.
17500. Constant speed
17501. Less vibration
17502. Rumble
17503. All of these
17504.
17505.
What is the width of recording tapes?
17506.
17507. 0.5 inch
17508. 0.75 inch
17509. 0.125 inch
17510. 1 inch
17511.
17512.
What frequency is used to erase tapes?
17513.
17514. Supersonic
17515. Subsonic

17516. Ultrasonic
17517. Infrasonic
17518.
17519.
What tape speed produces highest fidelity of audio?
17520.
17521. 20 in/sec
17522. 15 in/sec
17523. 10 in/sec
17524. 5 in /sec
17525.
17526.
What should be used to clean recording heads?
17527.
17528. Methanol
17529. Ethyl Alcohol
17530. Isopropyl alcohol
17531. Rubbing alcohol
17532.
17533.
What impedance is usually used with broadcast microphones?
17534.
17535. All of these
17536. 150 ohms
17537. 250 ohms
17538. 600 ohms
17539.
17540.
In what log is antenna-light information entered?
17541.
17542. Maintenance log
17543. Program log
17544. Operating log
17545. Logging log
17546.
17547.
What was the name of the first TV camera tube?
17548.
17549. Vidicon
17550. Iconoscope
17551. Image orthicon
17552. Kinescope
17553.
17554.
Which camera tube requires electron multipliers?
17555.
17556. Vidicon
17557. Iconoscope
17558. Image orthicon
17559. Kinescope
17560.
17561.
Which is used in closed-circuit TV?

17562.
17563. Vidicon
17564. Iconoscope
17565. Image orthicon
17566. Kinescope
17567.
17568.
What is the waveform of the sweep voltages?
17569.
17570. Trapezoidal
17571. Sawtooth
17572. Trigger
17573. Square
17574.
17575.
If the pulse peak is 100% modulation, what is the blanking level?
17576.
17577. 25%
17578. 50%
17579. 65%
17580. 75%
17581.
17582.
What device allows one camera to accept pictures from three or more projectors?
17583.
17584. Film multipliers
17585. Film demultiplexers
17586. Film multiplexers
17587. Film acceptor
17588.
17589.
What is the order of scanning four successive motion-picture frames for TV?
17590.
17591. 3,2,3,2
17592. 2,3,2,3
17593. 2,2,3,3
17594. 3,3,2,2
17595.
17596.
From the low-frequency end of a channel, what is the visual carrier frequency?
17597.
17598. 3.58 MHz
17599. 0.25 MHz
17600. 1.25 MHz
17601. 4.5 MHz
17602.
17603.
The circuits make up the front end of a TV receiver, except:
17604.
17605. RF
17606. Mixer
17607. IF

17608. Oscillator
17609.
17610.
What is the impedance at the antenna input terminals of a TV receiver?
17611.
17612. 300 ohms
17613. 150 ohms
17614. 50 ohms
17615. 100 ohms
17616.
17617.
Why are triodes and MOSFETs best for TV RF amplifiers?
17618.
17619. High power
17620. Efficiency
17621. Low noise
17622. High gain
17623.
17624.
In what circuit configuration are triodes and MOSFETs used?
17625.
17626. Cascade
17627. Darlington
17628. Cascade
17629. Shunt
17630.
17631.
The signal might a video amplifier amplify?
17632.
17633. Aural IF
17634. Video
17635. Blanking
17636. Any of these
17637.
17638.
When coupling from a sync separator, what is used to obtain the horizontal sync
pulses?
17639. Integrator
17640. Corrector
17641. Differentiator
17642. Separator
17643.
17644.
When coupling from a sync separator, what is used to obtain the vertical sync
pulses?
17645.
17646. Integrator
17647. Corrector
17648. Differentiator
17649. Separator
17650.
17651.
The type of active device used in horizontal output stages, except:?

17652.
17653. Vacuum tube
17654. FET
17655. BJT
17656. SCR
17657.
17658.
What should be produced by weak blue, weak green, and weak red signals on a
color CRT?
17659.
17660. White
17661. Shade
17662. Gray
17663. Off white
17664.
17665.
How many such mirrors are required in a color TV camera?
17666.
17667. One
17668. Two
17669. Three
17670. Four
17671.
17672.
What is the combining circuit called in TV?
17673.
17674. Combiner
17675. Multiplexer
17676. Integrator
17677. Mixer
17678.
17679.
What is the letter symbol for the luminance signal?
17680.
17681. R
17682. Q
17683. I
17684. Y
17685.
17686.
What is the total R + G + B for a Y signal?
17687.
17688. 0
17689. 1
17690. 2
17691. 1.5
17692.
17693.
If a white scene is picked up what is the Y value?
17694.
17695. 1
17696. 2

17697. 0
17698. 2.5
17699.
17700.
If a black scene is being picked up, what is the Y value?
17701.
17702. One
17703. 0.5
17704. Zero
17705. 1.5
17706.
17707.
What circuit does a color killer kill?
17708.
17709. Bandstop filter
17710. High-pass filter
17711. Low-pass filter
17712. Bandpass filter
17713.
17714.
If the blue dot is always at the bottom of a triad, what position must the blue gun
always have?
17715.
17716. Top
17717. Left side
17718. Right aside
17719. Center
17720.
17721.
How many cathodes in a shadow-mask picture tube?
17722.
17723. 1
17724. 2
17725. 3
17726. 4
17727.
17728.
How many guns in a shadow mask picture tube?
17729.
17730. 1
17731. 2
17732. 3
17733. 4
17734.
17735.
17736.
17737.
17738.
17739.
17740.
17741.

17742.
17743.
17744.
17745.
17746.
17747.
17748.
17749.
17750.
17751.
17752.
17753.
17754.
17755.
17756.
17757.
17758.
17759.
17760.
17761.
17762.
17763.
17764.
17765.
17766.
17767.
17768.
17769.

MULTIPLE CHOICE QUESTIONS IN

17770. TRANSMISSION
LINES
17771.

Electronics Systems and Technologies
17772. By
17773.

17774.
17775.
17776.
17777.
17778.
17779.

Melvin C. Arceo

17780.
17781.
17782.
17783.
17784.
17785.
17786.
17787.
17788.
17789.
17790.
17791.

17792. ENCODED BY:
ANDRADE, Caroline T.

17793.
17794.
Category of media with some form of conductor that provides a conduit in which
electromagnetic signals are contained.
17795.
17796. Guided
17797. Balanced
17798. Unguided
17799. Unbalanced
17800.
17801.
The conductive connections between elements which carry signals.
17802.
17803. Transmission Lines
17804. Antenna
17805. Frequency allocations
17806. Load
17807.
17808.
Calculate the characteristic impedance for a line that exhibits an inductance of 4
nH/m and 1.5pF/m
17809.
17810. 36.6 ohms
17811. 51.6 ohms
17812. 22 ohms
17813. 24.5 ohms
17814.
17815.
Category of media which are wireless
17816.
17817. Guided
17818. Balanced
17819. Unguided
17820. Unbalanced
17821.
17822.
It is a medium or any physical facility used to propagate electromagnetic signals
between two locations in a communications system.

17823.
17824. Transmission medium
17825. Channel allocation
17826. Frequency allocation
17827. Any of these
17828.
17829.
It is a metallic conductor system used to transfer electrical energy from one point
to another using electrical current flow.
17830. Transmitter
17831. Multiplexers
17832. Receiver
17833. Transmission line
17834.
17835.
A kind of wave where the displacement is in the direction of propagation.
17836.
17837. Transverse
17838. Longitudinal
17839. Reverse
17840. Perpendicular
17841.
17842.
Calculate the capacitance per meter of a 50-ohm load cable that has an inductance
of 55 nH/m.
17843.
17844. 13 pF
17845. 18 pF
17846. 20 pF
17847. 22 pF
17848.
17849.
The desirable SWR on a transmission line is
17850.
17851. 0
17852. 1
17853. 2
17854. Infinity
17855.
17856.
A kind of wave where the direction is displacement is perpendicular to the
direction of propagation.
17857.
17858. Transverse
17859. Longitudinal
17860. Reverse
17861. Perpendicular
17862.
17863.
A short-circuited half-wavelength line acts like a
17864.
17865. Parallel resonant circuit

17866. Series Resonant Circuit
17867. Oscillator
17868. LC circuit
17869.
17870.
Electromagnetic waves that travel along a transmission line from the source to the
load.
17871.
17872. Reverse waves
17873. Transverse waves
17874. Incident waves
17875. Longitudinal waves
17876.
17877.
Electromagnetic waves that travel from the load back toward the source.
17878.
17879. Incident waves
17880. Transverse waves
17881. Forward waves
17882. Reflected waves
17883.
17884.
Sound travels approximately
17885.
17886. 2200 feet per second
17887. 1100 feet per second
17888. 550 feet per second
17889. 600 feet per second
17890.
17891.
Determine the surge impedance for a parallel wire, air dielectric with a ratio of the
spacing between conductors and the diameter of 3
17892.
17893. 250 ohms
17894. 210 ohms
17895. 180 ohms
17896. 215 ohms
17897.
17898.
The rate at which the periodic wave repeats
17899.
17900. Wavelength
17901. Amplitude
17902. Period
17903. Frequency
17904.
17905.
The distance of one cycle occurring in space
17906.
17907. Wavelength
17908. Amplitudes
17909. Period

17910. Frequency
17911.
17912.
Classification of transmission line where both conductors carry current; one
conductor carries the signal, the other conductor is the return path
17913.
17914. Differential transmission lines
17915. Unbalanced lines
17916. Coaxial cables
17917. Balun
17918.
17919.
A shorted half-wave line at the operating frequency acts like
17920.
17921. Capacitor
17922. Inductor
17923. Series resonant circuit
17924. Parallel resonant circuit
17925.
17926.
What is the characteristic impedance of a coaxial line, air dielectric with a ratio of
the diameter of the outer and inner conductor equal to 1.5?
17927.
17928. 24.3 ohms
17929. 25.6 ohms
17930. 13.2 ohms
17931. 18 ohms
17932.
17933.
Currents that flow in opposite direction in a balanced wire pair is called
17934.
17935. Longitudinal currents
17936. Reverse circuit currents
17937. Transverse circuit currents
17938. Metallic circuit currents
17939.
17940.
Currents that flow in same direction in a balanced wire pair is called
17941.
17942. Longitudinal currents
17943. Reverse circuit currents
17944. Transverse circuit currents
17945. In-phase currents
17946.
17947.
A circuit device used to connect a balanced transmission line to an unbalanced
load
17948.
17949. Slotted lines
17950. Stub
17951. Balun
17952. Quarterwave lines

17953.
17954.
The most common type of balun used in relatively high frequency
17955.
17956. Narrowband
17957. Choke
17958. Sleeve
17959. All of these
17960.
17961.
A pattern of voltage and current variations along the transmission line not
terminated in its characteristic impedance is called
17962.
17963. An electric fluid
17964. Radio waves
17965. Standing waves
17966. A magnetic field
17967.
17968.
A type of parallel-conductor transmission lines consists of simply of two parallel
wires, closely-spaced and separated by air.
17969.
17970. Twisted pair
17971. Open-wire lines
17972. Coaxial cables
17973. Twin pair
17974.
17975.
A type of parallel-conductor transmission lines which is essentially the same as
open-wire transmission line except that the spacers between the conductors are replaced
with a continuous solid dielectric that ensures uniform spacing along the entire cable
17976.
17977. Twisted pair
17978. Open-wire lines
17979. Coaxial cables
17980. Twin lead
17981.
17982.
What is the range of size of wires of a twisted pair?
17983.
17984. AWG 16 to AWG 26
17985. AWG 14 to AWG 25
17986. AWG 10 to AWG 20
17987. AWG 12 to AWG 28
17988.
17989.
What is the characteristic impedance of a coaxial line, polyethylene dielectric
with the ratio of the diameter of the outer and the inner conductor of 2.5?
17990.
17991. 43.5 ohms
17992. 23.4 ohms
17993. 36.2 ohms

17994. 29.8 ohms
17995.
17996.
In AWG, the higher the wire gauge ______
17997.
17998. The higher the diameter and the lower the resistance
17999. The smaller the diameter and the higher the resistance
18000. The smaller the diameter and the higher the conductance
18001. The larger the diameter and the higher the resistance
18002.
Type of twisted pair wire cable that consists of two copper wires where each wire
is separately encapsulated in PVC insulation.
18003.
18004. Shielded twisted pair
18005. Twin lead
18006. Unshielded twisted pair
18007. Open wire frame
18008.
18009.
A shorted quarter-wave line at the operating frequency acts like
18010.
18011. Series resonant circuit
18012. Parallel resonant circuit
18013. Capacitor
18014. Inductor
18015.
18016.
The minimum number of twist for UTP is
18017.
18018. Two twist per foot
18019. Two twist per meter
18020. Three twist per foot
18021. Three twist per meter
18022.
18023.
A delay line using RG-8A/U cable is to exhibit a 5-ns delay. Calculate the
required length of the cable.
18024.
18025. 4.57 ft
18026. 1.23 ft
18027. 6.2 ft
18028. 3.4 ft
18029.
18030.
An open-circuited quarter-wavelength line acts like a
18031.
18032. Parallel resonant circuit
18033. Series resonant circuit
18034. Oscillator
18035. LC circuit
18036.
18037.
Level for category of UTP cable which is suitable only for voice grade telephone

signals and very low-speed data applications
18038.
18039. Level 1 or Cat 1
18040. Level 3 or Cat 3
18041. Level 2 or Cat 2
18042. Cat 4
18043.
18044.
An antenna is being fed by a properly terminated two-wire transmission line. The
current in the line at the input end is 3A. The surge impedance of the line is 500 ohms.
How much power is being supplied to the line?
18045.
18046. 3.1 kW
18047. 2.5 kW
18048. 1.6 kW
18049. 4.5 kW
18050.
18051.
Level or Category of UTP cable which was developed for IEEE 802.5 token ring
local area networks operating at a transmission rates of 4Mbps
18052.
18053. Level 1 or Cat 1
18054. Level 3 or Cat 3
18055. Level 2 or Cat 2
18056. Cat 4
18057.
18058.
If the period of one complete cycle of a radio wave is 0.000001 s, what is the
wavelength?
18059.
18060. 300 m
18061. 200 m
18062. 100 m
18063. 400 m
18064.
18065.
If the two towers of a 950-kHz antenna are separated by 120 electrical degrees,
what is the tower separation in feet?
18066.
18067. 231 ft
18068. 235 ft
18069. 176 ft
18070. 345 ft
18071.
18072.
Category of UTP used for virtually any voice or data transmission rate up to 16
Mbps, has a minimum of 3 turns per inch.
18073.
18074. Category 5e
18075. Category 4
18076. Category 5

18077. Category 3
18078.
18079.
The mismatch between the antenna and transmission line impedances cannot be
corrected for by
18080.
18081. Using an LC matching network
18082. Adjusting antenna length
18083. Using a balun
18084. Adjusting the length of transmission line
18085.
18086.
Category of UTP that was designed for data transmission rates up to 20 Mbps
18087.
18088. Category 5e
18089. Category 4
18090. Category 5
18091. Category 3
18092.
18093.
Variation of CAT5 cables that are intended for data transmission rates up to 250
Mbps
18094.
18095. Category 5e
18096. Category 2
18097. Category 6
18098. Category 3
18099.
18100.
A type of twisted-pair wherein its wires and dielectric are enclosed in a
conductive metal sleeve called a foil.
18101.
18102. STP
18103. Twin lead
18104. UTP
18105. Unshielded Twin lead
18106.
18107.
It is the name given to the area between the ceiling and the roof in a single-story
building or between the ceiling and the floor of the next higher level in a multistory
building.
18108.
18109. Attic
18110. Rooftop
18111. Plenum
18112. Ceiling
18113.
18114.
It consists of center conductor surrounded by dielectric material, then a concentric
shielding, and an environmental protection outer jacket.
18115.
18116. Twisted pair

18117. Coaxial cable
18118. Twin lead
18119. Open wire
18120.
18121.
In a transmission line, it refers to the woven stranded mesh or braid that surround
some types of coaxial cables
18122.
18123. Grounding
18124. Shielding
18125. Degaussing
18126. Any of these
18127.
18128.
A coaxial cable with one layer of foil insulation and one layer of braided
shielding.
18129.
18130. Backup shielding
18131. Temporary shielding
18132. Dual shielding
18133. Interference shielding
18134.
18135.
At very high frequencies, transmission lines are used as
18136.
18137. Tuned circuits
18138. Antennas
18139. Insulators
18140. Resistors
18141.
18142.
A coaxial cable with two layers of foil insulation and two layers of braided
shielding.
18143.
18144. Quad shielding
18145. Double shielding
18146. Triple shielding
18147. Shielding
18148.
18149.
A type of coaxial cable that has a tubular outer conductor surrounds the center
conductor coaxially and the insulating material is air
18150.
18151. Rigid air coaxial cable
18152. Gas-filled coaxial cable
18153. Solid coaxial cable
18154. Flexible cable
18155.
18156.
If the length of an open-circuited stub is less than quarter-wavelength but greater
than 0, the stub behaves as
18157.

18158. Inductor
18159. Capacitor
18160. Resistor
18161. Complex
18162.
18163.
Type of coaxial cable where the outer conductor is braided, flexible, and coaxial
to the center conductor.
18164.
18165. Gas-filled coaxial cable
18166. Rigid air coaxial cable
18167. Solid flexible coaxial cable
18168. Flexible cable
18169.
18170.
A 50-ohm coax is connected to a 73-ohm antenna. The SWR is
18171.
18172. 0.685
18173. 1
18174. 1.46
18175. 2.92
18176.
18177.
Defined as the impedance seen looking at an infinitely long line or the impedance
seen looking into a finite length of the line that is terminated in a purely resistive load
with the resistance equal to the characteristic impedance of the line.
18178.
18179. Input impedance
18180. Surge impedance
18181. Output impedance
18182. Circuit impedance
18183.
18184.
Determine the characteristic impedance for an air dielectric two-wire parallel
transmission line with a D/r ratio of 12.22
18185.
18186. 150 ohms
18187. 120 ohms
18188. 75 ohms
18189. 300 ohms
18190.
18191.
Determine the characteristic impedance for an RG-59A coaxial cable with the
following specifications: d=0.025 inches, D=0.15 inches, and dielectric constant of 2.23
18192.
18193. 120 ohms
18194. 72 ohms
18195. 150 ohms
18196. 75 ohms
18197.
18198.
Determine the characteristic impedance for an RG-59A coaxial cable with the

following specifications: L=0.118 uH/ft and C=21 pF/ft
18199.
18200. 150 ohms
18201. 72 ohms
18202. 75 ohms
18203. 100 ohms
18204.
18205.
It is used to express the attenuation or signal loss and the phase shift per unit
length of the transmission line.
18206.
18207. Propagation coefficient
18208. Propagation constant
18209. Propagation factor
18210. Any of these
18211.
18212.
For matched condition, what is the relationship of load and characteristic
impedance?
18213.
18214. Greater than
18215. Less than
18216. Equal
18217. Impossible to say
18218.
18219.
18220.
It is defined simply as the ratio of the actual velocity of propagation of an
electromagnetic wave through a given medium to the velocity of propagation through a
vacuum or free space.
18221.
18222. Velocity factor
18223. Velocity propagation
18224. Index of refraction
18225. Phase delay
18226.
18227.
It is simply the permittivity of the material
18228.
18229. Permittivity
18230. Insulation constant
18231. Dielectric constant
18232. Resistivity
18233.
18234.
For a given length of RG 8A/U coaxial cable with distributed capacitance of 96.6
pF/m, a distributed inductance of 241.56 nH/m, and a relative dielectric constant of 2.3,
determine the velocity of propagation
18235.
18236. 1.07 x 10^8 m/s
18237. 2.3 x 10^7 m/s

18238. 3.28 x 10^8 m/s
18239. 2.07 x 10^8 m/s
18240.
18241.
For a given length of RG 8A/U coaxial cable with distributed capacitance of 96.6
pF/m, a distributed inductance of 241.56 nH/m, and a relative dielectric constant of 2.3,
determine the velocity factor
18242.
18243. 1.2
18244. 0.66
18245. 0.7
18246. 0.5
18247.
18248.
If the length of an open-circuited stub is greater than quarter-wavelength but less
than half-wavelength, the stub behaves as
18249.
18250. Inductor
18251. Capacitor
18252. Resistor
18253. Complex
18254.
18255.
Delay line is a function of what two parameters?
18256.
18257. Resistance and capacitance
18258. Resistance and susceptance
18259. Inductance and resistance
18260. Inductance and capacitance
18261.
18262.
How is the time delay calculated in a coaxial cables with a dielectric constant of
0.66?
18263.
18264. 0.56 sec
18265. 0.67 sec
18266. 0.45 sec
18267. 1.2 sec
18268.
18269.
Three feet is one wavelength at a frequency of
18270.
18271. 100 MHz
18272. 164 MHz
18273. 300 MHz
18274. 328 MHz
18275.
18276.
When current flows through a conductor, the loss introduced as a function of
resistance and current is called _______
18277.
18278. Inductance loss

18279. Conductor loss
18280. Voltage loss
18281. Skin effect
18282.
18283.
For maximum absorption of power at the antenna, the relationship between the
characteristic impedance of the line Zo and the load impedance ZL should be
18284.
18285. Zo = ZL
18286. Zo > ZL
18287. Zo < ZL
18288. Zo = 0
18289.
18290.
The ratio of the AC resistance and the DC resistance
18291.
18292. Impedance ratio
18293. Susceptance ratio
18294. Resistance ratio
18295. Conductance ratio
18296.
18297.
The difference in potential between two conductors of a metallic transmission line
causes ______.
18298.
18299. Conductor loss
18300. Dielectric heating
18301. Radiation loss
18302. Corona
18303.
18304.
If the length of a short-circuited stub is greater than quarter-wavelength but less
than half-wavelength, the stub behaves as
18305.
18306. Inductor
18307. Capacitor
18308. Resistor
18309. Complex
18310.
18311.
If the separation between the conductors in a metallic transmission line is an
appreciable fraction of a wavelength, the electrostatic and electromagnetic fields that
surround the conductor cause the line to act as if it were an antenna and transfer energy to
any nearby material. This energy radiated is called ______.
18312.
18313. Radiation loss
18314. Power loss
18315. Coupling loss
18316. Corona
18317.
18318.
The minimum voltage along a transmission line is 260 V, while the maximum is

390 V. The SWR is
18319.
18320. 0.67
18321. 1.0
18322. 1.2
18323. 1.5
18324.
18325.
It occurs whenever a connection is made to or from a transmission line or when
two sections of transmission line are connected together
18326.
18327. Power loss
18328. Coupling loss
18329. Radiation loss
18330. Resistance loss
18331.
18332.
Which of the following is not a common transmission line impedance?
18333.
18334. 50 ohms
18335. 75 ohms
18336. 120 ohms
18337. 300 ohms
18338.
18339.
It is a luminous discharge that occurs between the two conductors of a
transmission line when the difference in potential between them exceeds the breakdown
voltage of a dielectric insulator.
18340.
18341. Resistance loss
18342. Corona
18343. Radiation loss
18344. Power loss
18345.
18346.
Voltage that propagates down the load
18347.
18348. Reflected voltage
18349. Standing wave ratio
18350. Incident voltage
18351. Reflection voltage
18352.
18353.
Voltage that propagates from the load towards the source
18354.
18355. Reflected voltage
18356. Standing wave ratio
18357. Reflection coefficient
18358. Incident voltage
18359.
18360.
A transmission line with no reflected power

18361.
18362. Flat
18363. Resistive
18364. Non resonant line
18365. Any of these
18366.
18367.
It is a vector quantity that represents the ratio of reflected voltage to incident
voltage or the reflected current and the incident current
18368.
18369. Reflection coefficient
18370. Reactive load diagram
18371. Standing wave ratio
18372. Traveling waves
18373.
18374.
With a mismatched line, two electromagnetic waves traveling in opposite
direction, present on the line on the same time.
18375.
18376. Standing wave ratio
18377. Reflection coefficient
18378. Standing waves
18379. Traveling waves
18380.
18381.
The two traveling waves sets up an interference pattern called _______.
18382.
18383. Standing wave ratio
18384. Reflection coefficient
18385. Standing waves
18386. Traveling waves
18387.
18388.
It is defined as the ratio of the maximum voltage to the minimum voltage or the
maximum current to the minimum current of a standing wave in a transmission line.
18389.
18390. Standing wave ratio
18391. Normalized impedance
18392. Reflection coefficient
18393. Any of these
18394.
18395.
For a transmission line with an incident voltage of 5V and a reflected voltage of
3V, determine the reflection coefficient.
18396.
18397. 0.4
18398. 0.6
18399. 0.5
18400. 0.7
18401.
18402.
A ratio expressing the percentage of incident voltage reflected on a transmission

line is known as the
18403.
18404. Velocity factor
18405. Standing wave ratio
18406. Reflection coefficient
18407. Line efficiency
18408.
18409.
There is an impedance inversion in every ______.
18410.
18411. Half wavelength
18412. Quarter wavelength
18413. Full wavelength
18414. Three-eights of a wavelength
18415.
18416.
The characteristic impedance of a transmission line does not depend upon its
18417.
18418. Length
18419. Conductor diameter
18420. Conductor spacing
18421. None of these
18422.
18423.
______ are used to match transmission lines to purely resistive loads whose
resistance is not equal to the characteristic impedance of the line.
18424.
18425. Stub
18426. Slotted lines
18427. Quarter-wavelength transformer
18428. Short circuited lines
18429.
18430.
To match a transmission line with a reactive load _______
18431.
18432. Use stub matching
18433. Use a slotted line
18434. Used a Q-section
18435. Use an open circuited lines
18436.
18437.
A technique that can be used to locate an impairment in metallic cable
18438.
18439. TDR
18440. Wattmeter
18441. Voltmeter
18442. SWR meter
18443.
18444.
A pulse is transmitted down a cable that has a velocity of propagation of 0.8c. The
reflected signal is received 1us later. How far down the cable is the impairment?
18445.

18446. 240 m
18447. 15 m
18448. 60 m
18449. 120 m
18450.
18451.
Using TDR, a transmission line impairment is located 3000m from the source. For
a velocity propagation of 0.9c, determine the time elapsed from the beginning of the
pulse to the reception of the echo
18452.
18453. 11.11 us
18454. 10.12 us
18455. 22.22 us
18456. 21.14 us
18457.
18458.
A flat conductor separated from a ground plane by an insulating dielectric
material
18459.
18460. Stripline
18461. Waveguide
18462. Microstrip
18463. Coaxial cable
18464.
18465.
A flat conductor sandwich between two ground planes.
18466.
18467. Stripline
18468. Waveguide
18469. Microstrip
18470. Coaxial cable
18471.
18472.
Indicate the false statement. The SWR on a transmission line is infinity; the line is
terminated in
18473.
18474. A short circuit
18475. A complex impedance
18476. An open circuit
18477. A pure reactance
18478.
18479.
The most commonly used transmission line is a
18480.
18481. Two-wire balance line
18482. Singe wire
18483. Three-wire line
18484. Coax
18485.
18486.
A short-circuited half-wavelength line acts like a
18487.

18488. Parallel resonant circuit
18489. Series resonant circuit
18490. Oscillator
18491. LC circuit
18492.
18493.
A (75-j50)-ohm is connected to a coaxial transmission line of Zo = 75 ohms, at 10
GHz. The best method of matching consists of connecting
18494.
18495. A short-circuited stub at the load
18496. An inductive at the load
18497. A capacitance at some specific distance from the load
18498. A short-circuited stub at some specific distance from the load
18499.
18500.
The velocity factor of a transmission line
18501.
18502. Depends on the dielectric constant of the material used
18503. Increases in velocity along the transmission line
18504. Is governed by the skin effect
18505. Is higher for a solid dielectric than for air.
18506.
18507. Impedance inversion may be obtained with
18508.
18509. A short-circuited stub
18510. An open-circuited stub
18511. A quarter-wave line
18512. A half-wave line
18513.
18514. The most desirable reflection coefficient is
18515.
18516. 0
18517. 0.5
18518. 1
18519. Infinity
18520.
18521. Short circuited stubs are preferred to open-circuited stub because the latter are
18522.
18523. More difficult to make and connect
18524. Made of a transmission line with different characteristic impedance
18525. Liable to radiate
18526. Incapable of giving a full range of reactance
18527.
18528. For transmission-line load matching over a range of frequencies, it is best to use a
18529.
18530. Balun
18531. Broadband directional coupler
18532. Double stub

18533. Single stub of adjustable position
18534.
18535. The main disadvantage of the two-hole directional coupler is
18536.
18537. Low directional coupling
18538. Poor directivity
18539. High SWR
18540. Narrow bandwidth
18541.
18542. To couple a coaxial line to a parallel-wire line, it is best to use a
18543.
18544. Slotted line
18545. Balun
18546. Directional coupler
18547. Quarter-wave transformer
18548.
18549. A short-circuited quarter-wavelength line acts like a
18550.
18551. Parallel resonant circuit
18552. Series resonant circuit
18553. Oscillator
18554. LC circuit
18555.
18556. If the length of a short-circuited stub is less than a quarter-wavelength but greater
than 0, the stub behaves as
18557.
18558. Inductor
18559. Capacitor
18560. Resistor
18561. Complex
18562.
18563. The depth of penetration of current density resulting from skin effect
18564.
18565. Skin depth
18566. Wire depth
18567. Line depth
18568. Medium depth
18569.
18570. Transmission line must be matched to the load to
18571.
18572. Transfer maximum voltage to the load
18573. Transfer maximum current to the load
18574. Reduce the load current
18575. Transfer maximum power to the load
18576.
18577. Referred to the dielectric constant of a transmission line material

18578.
18579. Inductance and capacitance
18580. Velocity factor
18581. Characteristic impedance
18582. Propagation velocity
18583.
18584. A transmission line containing of two conductors that have equal resistance per unit
length
18585.
18586. Unbalanced line
18587. Open-wire line
18588. Balanced line
18589. Coaxial cable
18590.
18591. Which of the following determines the characteristics of a transmission line?
18592.
18593. Inductance
18594. Capacitance
18595. Physical dimension
18596. Length
18597.
18598. Category of UTP that was designed for data transmission rates up to 20 Mbps
18599.
18600. Category 5e
18601. Category 4
18602. Category 5
18603. Category 3
18604.
18605. Level 2 or category 2 UTP cables comply with IBM’s _______ specification.
18606.
18607. Type 1
18608. Type 3
18609. Type 2
18610. Type 4
18611.
18612. Level 3 or Category 3 UTP cables should have at least ____ twist per inch.
18613.
18614. 1
18615. 2
18616. 3
18617. 4
18618.
18619. Which of the following is NOT a color code for Category 5 UTP?
18620.
18621. Blue/white stripe and blue
18622. Orange/white stripe and orange

18623. Red/white stripe and red
18624. Brown/white stripe and brown
18625.
18626. Shielded-screen twisted-pair cable or SSTP is also known as ________.
18627.
18628. Cat 5e
18629. Cat 7
18630. Cat 6
18631. Cat 8
18632.
18633. An open-circuited transmission line quarter wavelength long is equivalent to
18634.
18635. Parallel resonant circuit
18636. Series resonant circuit
18637. Inductive
18638. Capacitive
18639.
18640. A short-circuited transmission line more than quarter-wavelength long but shorter
than half wavelength is equivalent to _______.
18641.
18642. Series resonant circuit
18643. Inductive
18644. Capacitive
18645. Parallel resonant circuit
18646.
18647. A short-circuited transmission line less than quarter-wavelength long.
18648.
18649. Inductive
18650. Capacitive
18651. Parallel resonant circuit
18652. Series resonant circuit
18653.
18654. The quarter-wavelength transformer line acts as a transformer with a 1:1 turns ratio
when the load resistance is with what relationship with the characteristic impedance of
the quarter-wavelength transformer?
18655.
18656. Equal
18657. Less than
18658. Greater than
18659. None of these
18660.
18661. The characteristic impedance of a microstrip is equal to _____ ohms.
18662.
18663. 50 to 200
18664. 25 to 50
18665. 100 to 200

18666. 50 to 75
18667.
18668. The quarter-wavelength transformer line acts as a step down transformer when the
load resistance is with what relationship with the characteristic impedance of the quarterwavelength transformer?
18669.
18670. Equal
18671. Less than
18672. Greater than
18673. None of these
18674.
18675.
18676. The typical value of the velocity factor of an open-wire transmission line is
18677.
18678. 0.8
18679. 0.7
18680. 0.6
18681. 0.9
18682.
18683. If a transmission line is not terminated in its characteristic impedance, _______ will
develop along the line.
18684.
18685. Traveling waves
18686. Standing waves
18687. Surge impedance
18688. Infinite impedance
18689.
18690. If a load and a line have mismatched impedances, power not absorbed by the load
will be _____.
18691.
18692. Absorbed
18693. Rejected
18694. Reflected
18695. Removed
18696.
18697.
18698.
18699.
18700.
18701.
18702.
18703.
18704.

18705.
18706.
18707.
18708.
18709.
18710.
18711.
18712.
18713.

18714. MULTIPLE CHOICE QUESTIONS IN

18715. INTRODUCTION
TO COMMUNICATIONS
18716.

Electronics Systems and Technologies
18717. By
18718.

Melvin C. Arceo
18719.
18720.
18721.

18722.
18723.
18724.
18725.

18726. ENCODED BY:
GARCIA, Virginia Nonna H.

18727.
18728.
It is the transmission, reception, and processing of information between two or
more locations using electronic circuits.
18729. Electronic communications
18730. Electronic transfer
18731. Electronic mode
18732. Electronic codes
18733.
18734.
The noise produced by a resistor is to be amplified by a noiseless amplifier having
a voltage gain of 75 and a bandwidth of 100 kHz. A sensitive meter at the output reads

240 microvolts rms. Assuming operation of 37 degrees, calculate the resistor’s resistance.
18735. 4 kilo ohms
18736. 5 kilo ohms
18737. 6 kilo ohms
18738. 7 kilo ohms
18739.
18740.
The first electronic communications system was develop in what century?
18741. 17th
18742. 19th
18743. 18th
18744. 20th
18745.
18746.
Who was the first to successfully transmit wireless radio signals through Earth’s
atmosphere?
18747. Samuel Morse
18748. Howard Armstrong
18749. Lee DeForest
18750. Guglielmo Marconi
18751.
18752.
Who invented frequency modulation?
18753. Guglielmo Marconi
18754. Thomas Watson
18755. Alexander Graham Bell
18756. Howard Armstrong
18757.
18758.
A component of the electronic communication system that provides a means of
transporting signals from a transmitter to a receiver.
18759. Information
18760. modulator
18761. medium
18762. transmitter
18763.
18764.
Calculate the noise power outputs of a 1 kilo ohm resistor at 27 degrees C over a
100-kHz bandwidth.
18765. 4.14 fW
18766. 0.414 fW
18767. 14.1 fW
18768. 141 fW
18769.
18770.
_________ is a collection of electronic devices and circuits that accepts the
transmitted signals from the transmission medium and converts them back to their
original form.
18771. channel
18772. receiver
18773. transmitter
18774. antenna

18775.
18776.
A signal that carries the information through the system.
18777. information
18778. modulating signal
18779. intelligence
18780. carrier
18781.
18782.
A signal that modulates a high-frequency signal or carrier in order to transfer
information from one location to another
18783. intelligence
18784. modulated signal
18785. carrier
18786. intelligence or modulated signal
18787.
18788.
Fourier series shows that a sawtooth wave consists of the following except
18789. fundamental and subharmonic sine waves
18790. a fundamental sine wave and an infinite number of harmonics
18791. fundamental and harmonic sine waves whose amplitude decreases with the
harmonic number
18792. sinusoidal voltages, some of which are small enough to ignore in practice
18793.
18794.
Determine the noise current for a diode with a forward bias of 1mA over a 1 MHz
bandwidth.
18795. 19.8 nA
18796. 17.9 nA
18797. 12.3 nA
18798. 15 nA
18799.
18800.
The process of changing one or more properties of the carrier in proportion with
the information signal?
18801. demodulation
18802. transmission
18803. modulation
18804. reception
18805.
18806.
A system where digital pulses are transferred between two points in a
communication system.
18807. digital transmission
18808. analog transmission
18809. digital radio
18810. analog communications system
18811.
18812.
It is the transmittal of digitally modulated analog carriers between two or more
points in a communication system.
18813. analog transmission
18814. digital radio

18815. digital communications
18816. digital reception
18817.
18818.
Type of modulation where the carrier amplitude is varied proportional to the
information signal.
18819. AM
18820. PM
18821. FM
18822. Pulse modulation
18823.
18824.
In FM, the _________ is varied proportional to the information signal.
18825. phase
18826. time
18827. amplitude
18828. frequency
18829.
18830.
A circuit that performs modulation
18831. demodulator
18832. synthesizer
18833. modulator
18834. limiter
18835.
18836.
Calculate the signal to noise ratio for a receiver output of 4V signal and 0.48V
noise in dB
18837. 18.5 dB
18838. 69 dB
18839. 25.4 dB
18840. 9.25 dB
18841.
18842.
Modulation used is to the following except
18843. reduce the bandwidth used
18844. separate differing transmission
18845. ensure that intelligence may be transmitted over long distance
18846. allow the use of practicable antennas
18847.
18848.
It performs the reverse process of modulation and converts the modulated carrier
back to the original information.
18849. oscillator
18850. demodulator
18851. synthesizer
18852. mixer
18853.
18854.
Indicate the false statement. The reasons why modulation is necessary in
electronic communications is because:
18855. It is extremely difficult to radiate low-frequency signals from antenna in the form
of electromagnetic energy.

18856. Information signals often occupy the same frequency band and, if signals from
two or more sources at the same time, they would interfere with each other.
18857. To reduce the size of the capacitors and inductors of the tuned circuit.
18858. To increase the size of the transmitting and receiving antenna.
18859.
18860.
The process of converting a frequency or band of frequencies to another location
in the total frequency spectrum is called:
18861. translation
18862. demodulation
18863. modulation
18864. oscillation
18865.
18866.
An intricate part of electronic communication system because of its up-and-downconversion functions as they are transported through a channel.
18867. oscillation
18868. modulation
18869. demodulation
18870. translation
18871.
18872.
_________ is simply the number of times a periodic motion occurs in a given unit
of time
18873. frequency
18874. time
18875. period
18876. phase
18877.
18878.
The difference between the highest and the lowest frequencies contained in the
information.
18879. noise
18880. bandwidth
18881. interference
18882. frequency
18883.
18884.
It is a highly theoretical study of the efficient use of bandwidth to propagate
information through electronic communications systems.
18885. information capacity
18886. information bandwidth
18887. information theory
18888. information entropy
18889.
It is the measure of how much information can be transferred through a
communications system in a given period of time.
18890. information bandwidth
18891. information capacity
18892. information density
18893. information theory
18894.

18895.
The law that states that the wider the bandwidth and the longer the time of
transmission, the more information that can be conveyed through the system.
18896. Information theory
18897. Information density law
18898. Hartley’s law
18899. Information entropy law
18900.
18901.
A circuit configuration that involves one wire for the signal and one for the
reference or ground.
18902. 2-wire
18903. 4-wire
18904. 3-wire
18905. 1-wire
18906.
18907.
A circuit configuration that involves two for signal and two for reference or
ground.
18908. 2-wire
18909. 4-wire
18910. 3-wire
18911. 1-wire
18912.
18913.
It is used to match impedances and provide isolation between the two directions
of signal flow.
18914. 2-wire
18915. hybrid set
18916. 4-wire transmission
18917. suppressors
18918.
18919.
An interface circuit that is used when a two-wire circuit is connected to a fourwire circuit, as in long-distance telephone call.
18920. suppressors
18921. echo limiter
18922. codec
18923. terminating set
18924.
18925.
An amplifier with a noise figure of 6dB has an input signal-to-noise ratio of 25dB.
Calculate the output signal-to-noise ratio in dB.
18926. 31 dB
18927. 19 dB
18928. 20 dB
18929. 25 dB
18930.
18931.
It is the process of combining two or more signals and is an essential process in
electronic communications.
18932. oscillation
18933. mixing

18934. damping
18935. modulation
18936.
18937.
_________ occurs when two or more signals combine in a linear device, such as a
passive network or a small-signal amplifier.
18938. non-linear mixing
18939. linear-phase filtering
18940. linear summing
18941. bandlimiting
18942.
18943.
One of the following is not a useful quantity for comparing the noise performance
of receivers:
18944. input noise voltage
18945. equivalent noise resistance
18946. noise temperature
18947. noise figure
18948.
18949.
A single-stage amplifier has a 200-kHz bandwidth and a voltage gain of 100 at
room temperature. Assume that the external noise is negligible and that a 1-mV signal is
applied to the amplifier’s input. Calculate the output noise voltage if the amplifier has a
5-dB NF and the input noise is generated by a 2-kilo ohm resistor.
18950. 56.58 nV
18951. 458 uV
18952. 595.6 nV
18953. 356 uV
18954.
18955.
In a communication system, which of the following reduces the information
capacity of the system.
18956. linear-phase filtering
18957. mixing
18958. bandlimiting
18959. modulation
18960.
18961.
_________ occurs when two or more signals are combined in a non-linear device
such as a diode or large-signal amplifier.
18962. modulation
18963. non-linear summing
18964. oscillation
18965. non-linear filtering
18966.
Measuring physical condition of some remote location and transmitting this data
for analysis is the process of
18967. Telemetry
18968. Instrumentation
18969. Modulation
18970. Multiplexing
18971.

18972.
It is defined as any undesirable electrical energy that falls within the passband of
the signal.
18973. interference
18974. noise
18975. splatter
18976. out-of-band signalling
18977.
18978.
_________ noise that is present regardless of whether there is a signal present or
not.
18979. atmospheric noise
18980. correlated
18981. uncorrelated
18982. internal
18983.
18984.
A three stage amplifier has an input stage with noise ratio of 5 and power gain of
50. Stages 2 and 3 have a noise ratio of 10 and power gain of 1000. Calculate the noise
figure for the overall system.
18985. 4.55 dB
18986. 7.14 dB
18987. 6 dB
18988. 5.18 dB
18989.
18990.
In communication system, noise is most likely to affect the signal
18991. at the transmitter
18992. in the channel
18993. in the information source
18994. at the information
18995.
18996.
Which of the following is not true?
18997. HF mixers are generally noisier than HF amplifiers
18998. Impulse noise voltage is independent of bandwidth
18999. Thermal noise is independent of the frequency at which it is measured.
19000. Industrial noise is usually of the impulse type
19001.
19002.
It is a type of noise that is generated outside the device of circuit.
19003. shot noise
19004. noise voltage
19005. thermal noise
19006. external noise
19007.
_________ noise is a naturally occurring electrical disturbances which is
commonly called static electricity.
19008. Transit-time noise
19009. Extraterrestrial noise
19010. Solar noise
19011. Atmospheric noise
19012.

19013.
What is the noise whose source is in a category different from that of the other
three.
19014. solar noise
19015. cosmic noise
19016. atmospheric noise
19017. galactic noise
19018.
19019.
A microwave antenna with an equivalent noise temperature of 25 K is coupled
through a network with an equivalent noise temperature of 30 K to a microwave receiver
with an equivalent noise temperature of 60 K referred to its input. Calculate the noise
power at its input for a 2-MHz bandwidth.
19020. 3.15 fW
19021. 4.35 fW
19022. 2.12 fW
19023. 1.24 fW
19024.
19025.
Which of the following is not another name of thermal agitation noise?
19026. White noise
19027. Pink noise
19028. Johnson noise
19029. Brown noise
19030.
19031.
Any modification to a stream of carriers as they pass from the input to the output
of a device produces an irregular, random variation is called _________ noise.
19032. Transit-time noise
19033. Man-made noise
19034. Thermal noise
19035. Internal noise
19036.
19037.
One of the following types of noise becomes of great importance at high
frequencies. It is the
19038. shot noise
19039. random noise
19040. impulse noise
19041. transit-time noise
19042.
19043.
The noise that was first observed in the anode current of a vacuum tube amplifier
and was described mathematically by W. Schottky in 1918.
19044. Shot noise
19045. Transit-time noise
19046. External noise
19047. Thermal agitation noise
19048.
19049.
Also known as black-body noise
19050. cosmic noise
19051. extraterrestrial noise

19052. solar noise
19053. man made noise
19054.
19055.
Also known as deep-space noise
19056. solar noise
19057. cosmic noise
19058. extraterrestrial noise
19059. galactic noise
19060.
19061.
_________ noise is noise that is mutually related to the signal and cannot be
present in a circuit unless there is an input signal input.
19062. solar noise
19063. uncorrelated noise
19064. correlated noise
19065. noise voltage
19066.
19067.
The square of the thermal noise voltage generated by a resistor is proportional to
19068. its resistance
19069. its temperature
19070. Boltzmann’s constant
19071. The bandwidth over which it is measured
19072.
19073.
It is a type of distortion that when unwanted harmonics of a signal are produced
through a nonlinear amplification.
19074. intermodulation distortion
19075. buck-shot
19076. splatter
19077. harmonic distortion
19078.
19079.
Which of the following is not used for communications
19080. X-rays
19081. Millimeter waves
19082. Infrared
19083. Microwaves
19084.
19085.
_________ are integer multiples of the original input signal.
19086. interference
19087. harmonic
19088. fundamental
19089. distortion
19090.
A type of distortion that results from the generation of unwanted sum and
difference frequencies when two or more signals are amplified in a linear device, such as
a large-signal amplifier.
19091. harmonic distortion
19092. intermodulation distortion
19093. interference

19094. cross talk
19095.
19096.
A form of noise that is characterized by its capability to disturb or distract.
19097. impulse noise
19098. man-made noise
19099. solar noise
19100. interference
19101.
19102.
A type of noise that is characterized by high-amplitude peaks of short duration in
the total noise spectrum.
19103. transit-time noise
19104. solar noise
19105. thermal noise
19106. impulse noise
19107.
19108.
_________ is a figure of merit used to indicate how much the signal-to-noise ratio
deteriorates as a signal passes through a circuit or series of circuits.
19109. SINAD
19110. Q-factor
19111. Noise figure
19112. S/N ratio
19113.
19114.
The value of resistor creating thermal noise is doubled. The noise power
generated therefore
19115. halved
19116. quadrupled
19117. doubled
19118. unchanged
19119.
19120.
Electromagnetic waves produced primarily by heat are called
19121. Infrared
19122. Microwaves
19123. Shortwaves
19124. X-ray
19125.
19126.
Receiving electromagnetic emission from stars is called
19127. Astrology
19128. Optical astronomy
19129. Radio astronomy
19130. Space surveillance
19131.
It is a collection of electronic components and circuits designed to convert the
information into a signal suitable for transmission over a given communication medium.
19132. receiver
19133. medium
19134. transmitter
19135. mixer

19136.
19137.
It is where the electronic signal is sent from one place to another.
19138. receiver
19139. transmitter
19140. source
19141. channel
19142.
19143.
It is a broad general term applied to any form of wireless communication from
one point to another.
19144. radio
19145. frequency
19146. signal
19147. spectrum
19148.
19149.
Collection of electronic components and circuits that accept the transmitted
message from the channel and convert it back into a form understandable by humans.
19150. receiver
19151. medium
19152. transmitter
19153. converter
19154.
19155.
It is a random, undesirable, electric energy that enters a communications system
via the communicating medium and interferes with the transmitted message.
19156. interference
19157. noise
19158. distortion
19159. fluctuations
19160.
19161.
A system that transmits information about the physical status of the satellite
including the position and temperature.
19162. telecommand
19163. telemovement
19164. television
19165. telemetry
19166.
19167.
Regardless of whether information is analog or digital, these signals are referred
to as _________.
19168. broadband
19169. composite
19170. baseband
19171. any of these
19172.
19173.
Putting the original voice, video, or digital data directly into the medium is
referred to as _________.
19174. baseband transmission
19175. composite transmission

19176. broadband transmission
19177. data transmission
19178.
19179.
It is the process of having a baseband voice, video, or digital signal modify
another, higher-frequency signal.
19180. mixing
19181. summing
19182. heterodyning
19183. modulation
19184.
19185.
It is the process of transmitting two or more signals simultaneously over the same
channel.
19186. modulation
19187. multiplexing
19188. summing
19189. demodulation
19190.
19191.
The entire range of frequencies is referred to as _________.
19192. frequency spectrum
19193. signals spectrum
19194. electromagnetic spectrum
19195. radio spectrum
19196.
19197.
What is the wavelength in meters, if the frequency is 10 MHz?
19198. 30
19199. 0.3
19200. 3
19201. 300
19202.
19203.
Musical instruments makes sounds usually in what range?
19204. LF
19205. VLF
19206. VF
19207. HF
19208.
19209.
Range of electromagnetic spectrum used in navy to communicate submarines
19210. VLF
19211. LF
19212. HF
19213. UHF
19214.
Frequencies above 1 GHz range is called _________.
19215. milliwaves
19216. microwaves
19217. centiwaves
19218. hectowaves
19219.

19220.
The range of long infrared is
19221. 0.01 mm to 1000 nm
19222. 0.01 mm to 700 nm
19223. 1000nm to 700 nm
19224. 0.4 um to 0.8 um
19225.
19226.
A radiation that is generally associated with heat.
19227. ultraviolet
19228. visible light
19229. infrared
19230. EHF
19231.
19232.
Infrared occupies approximately
19233. 0.01 mm to 1000nm
19234. 0.01 mm to 700 nm
19235. 1000nm to 700 nm
19236. 0.4 um to 0.8 um
19237.
19238.
Light is a special type of electromagnetic radiation which has a wavelength range
of
19239. 0.01 mm to 1000nm
19240. 0.01 mm to 700 nm
19241. 1000nm to 700 nm
19242. 0.4 um to 0.8 um
19243.
19244.
The approximate frequency of a red
19245. 8000 Angstrom
19246. 800 Angstrom
19247. 4000 Angstrom
19248. 400 Angstrom
19249.
19250.
It is the portion of electromagnetic spectrum occupied by the signal.
19251. spectrum
19252. composite
19253. bandwidth
19254. multiplexed
19255.
19256.
It is the frequency range over which an information signal is transmitted or over
which a receiver or other electronic equipment operate.
19257. composite
19258. bandwidth
19259. summed frequency
19260. signals
19261.
19262.
The range of frequencies required to transmit the desired information.
19263. channel bandwidth

19264. information capacity
19265. information bandwidth
19266. channel capacity
19267.
19268.
The first complete system of wireless communications was provided by
19269. Samuel Morse
19270. Guglielmo Marconi
19271. James Maxwell
19272. Heinrich Hertz
19273.
19274.
Calculate the noise power at the input of a microwave receiver with an equivalent
noise temperature of 45 K. It is fed from an antenna with a 35 K equivalent noise
temperature and operates over a 5-MHz bandwidth.
19275. 3.56 fW
19276. 1.34 fW
19277. 2.98 fW
19278. 5.52 fW
19279.
19280.
It is the process of putting information onto a high-frequency carrier for
transmission.
19281. multiplexing
19282. modulation
19283. mixing
19284. heterodyning
19285.
19286.
It is generally a device that converts energy from one form to another.
19287. transformer
19288. motor
19289. transducer
19290. generator
19291.
19292.
Man-made noise occurs randomly at frequencies up to around
19293. 100 Hz
19294. 300 kHz
19295. 200 MHz
19296. 500 MHz
19297.
19298.
What is the seventh harmonic of 360 kHz?
19299. 2520 kHz
19300. 46.08 MHz
19301. 3.6 x 10^12 Hz
19302. 1980 kHz
19303.
Atmospheric noise is not a significant factor for frequencies exceeding about
_________.
19304. 30 MHz
19305. 50 MHz

19306. 10 MHz
19307. 25 MHz
19308.
19309.
Space noise contains less energy below
19310. 9 MHz
19311. 15 MHz
19312. 20 MHz
19313. 8 MHz
19314.
19315.
The process of converting a frequency or band of frequencies to another location
in the
19316.
total frequency spectrum
19317.
a. modulation
19318.
b. detection
19319.
c. frequency translation
19320.
d. amplification
19321.
19322.
101.What is frequency range of EHF?
19323.
a. 3 – 30 GHz
19324.
b.30 – 300 GHz
19325.
c. 30 – 300 MHz
19326.
d. 300 – 3000 MHz
19327.
19328.
Calculate the wavelength in free space corresponding to a frequency of AM radio
19329.
broadcast band of 1 MHz
19330.
a. 300 m
19331.
b. 7.5 m
19332.
c. 11.1 m
19333.
d. 3.25 m
19334.
19335.
When the input power is reduced in half at the output, the signal power is said to
be
19336.
reduced by:
19337.
a. 2 dB
19338.
b. 6 dB
19339.
c. 4 dB
19340.
d. 3 dB
19341.
19342.
104. A current change that is equal to twice its original value will
correspond to a change of
19343.
a. 3 dB
19344.
b. 9 dB
19345.
c. 10 dB
19346.
d. 6 dB
19347.
19348.
There are four networks in series. The first network has a gain of 15 dB, the

second has
19349.
a loss of 4 dB, the third gain of 35 dB, and the fourth a loss of 5 dB. The
input of the first network is +3dBm. What is the output to the last network in mW.
19350.
a. 15913.1
19351.
b. 19922.9
19352.
c. 25118.9
19353.
d. 29523.6
19354.
19355.
The PLL is often combined with _________ circuits to produce multiple
frequencies.
19356.
a. Local oscillator
19357.
b. Mixer
19358.
c. RF amplifier
19359.
d. AF amplifier
19360.
19361.
Flicker noise may be completely ignored above about _________.
19362.
a. 500 Hz
19363.
b. 350 Hz
19364.
c. 225 Hz
19365.
d. 300 Hz
19366.
19367.
Determine the noise figure for an equivalent noise temperature of 75 K.
19368.
a. 1 dB
19369.
b. 3 dB
19370.
c. 2 dB
19371.
d. 1.25 dB
19372.
19373.
What is the other name for HF?
19374.
a. microwaves
19375.
b. short waves
19376.
c. millimeter waves
19377.
d. audio waves
19378.
19379.
It is a resistive network that is used to introduce a fixed amount of attenuation
between the source and a load.
19380.
a. limiter
19381.
b. clipper
19382.
c. mixer
19383.
d. attenuator
19384.
19385.
A technique used in improving communication when a high peak-to-average
power ratio of atmospheric noise occurs, the receiver is disabled during the duration of
these burst.
19386.
a. quieting
19387.
b. noise blanking
19388.
c. limiting

19389.
d. mixing
19390.
19391.
It is the ratio of the signal power level to noise power level
19392.
a. noise figure
19393.
b. signal-to-noise ratio
19394.
c. SINAD
19395.
d. noise improvement factor
19396.
19397.
It is a figure of merit used to indicate how much the signal-to-noise ratio
deteriorates as a signal passes through a circuit or series of circuits.
19398.
a. Q-factor
19399.
b. signal-to-noise ratio
19400.
c. noise factor
19401.
d. numerical aperture
19402.
19403.
What is the major contributor of transistor noise?
19404.
a. thermal agitation noise
19405.
b. pink noise
19406.
c. flicker noise
19407.
d. shot noise
19408.
19409.
Which of the following is not known as excess noise?
19410.
a. pink noise
19411.b. 1/f noise
19412.
c. flicker noise
19413.
d. brown noise
19414.
19415.
It is the relative measure of the desired signal power to the noise power
19416.
a. noise factor
19417.
b. signal-to-noise ratio
19418.
c. noise figure
19419.
d. noise improvement factor
19420.
19421.
Which of the following is a desirable value of signal-to-noise ratio in dB?
19422.
a. 0
19423.
b. 100
19424.
c. 1
19425.
d. 50
19426.
19427.
It is the range of frequency in which the upper frequency is double the lower
frequency
19428.
a. decade
19429.
b. pentade
19430.
c. octave
19431.
d. none of these
19432.

19433.
Which of the following noise figure is more desirable?
19434.
a. 0 dB
19435.
b. 100 dB
19436.
c. 1 dB
19437.
d. infinity
19438.
19439.
The formula used to measure the total noise figure due to amplifiers in cascade is
called _________.
19440.
a. Johnson’s formula
19441.
b. Shannon’s formula
19442.
c. Hartley’s formula
19443.
d. Friss’ formula
19444.
19445.
It is defined as to fluctuate between two states or conditions.
19446.
a. oscillate
19447.
b. synchronization
19448.
c. amplify
19449.
d. signal generation
19450.
19451.
An oscillator is _________ when the changes in a waveform are continuous and
repetitive and occurs in a periodic rate.
19452.
a. locking
19453.
b. one-shot
19454.
c. triggered
19455.
d. self-sustaining
19456.
19457.
A free-running oscillator is also called _________.
19458.
a. one-shot
19459.
b. triggered
19460.
c. locking
19461.
d. self-sustaining
19462.
19463.
Oscillators that are not self-sustaining are called _________.
19464.
a. free-running
19465.
b. feedback
19466.
c. triggered
19467.
d. regenerative
19468.
19469.
An oscillator that is an amplifier with a feedback loop.
19470.
a. signal generator
19471.
b. feedback oscillator
19472.
c. frequency synthesizer
19473.
d. frequency synchronization circuit
19474.
19475.
For a feedback circuit to sustain oscillation, the net voltage gain around the
feedback loop must be unity or greater, and the net phase shift around the loop must be

positive integer multiply of 360 degrees.
19476.
a. Barkhausen criterion
19477.
b. Butterworth criterion
19478.
c. Flywheel effect
19479.
d. Feedback criterion
19480.
19481.
A circuit which comprises of a voltage amplifier with an open-loop voltage gain, a
frequency-determining regenerative feedback path with a feedback ratio and either a
summer or subtractor circuit.
19482.
a. amplifier
19483.
b. closed-loop
19484.
c. power source
19485.
d. open-loop
19486.
19487.
It is the overall voltage gain of the complete circuit with the feedback loop closed
and is always less than the open-loop voltage gain.
19488.
a. feedback ratio
19489.
b. closed-loop voltage gain
19490.
c. open-loop current gain
19491.
d. close-loop current gain
19492.
19493.
It is the transfer function of the feedback network.
19494.
a. feedback ratio
19495.
b. closed-loop current gain
19496.
c. open-loop voltage gain
19497.
d. open-loop current gain
19498.
19499.
It is an untuned RC shift oscillator that uses both positive and negative feedback.
19500.
a. LC tank circuit
19501.
b. Colpitts oscillators
19502.
c. Hartley oscillators
19503.
d. Wein-Bridge oscillators
19504.
19505.
Its operation involves an exchange of energy between kinetic and potential.
19506.
a. Wein-Bridge oscillators
19507.
b. LC tank circuit
19508.
c. Clapp oscillators
19509.
d. Hartley oscillators
19510.
19511.
It is the ability of an oscillator to remain at as fixed frequency and is of primary
importance in a communications system
19512.
a. oscillation
19513.
b. synchronization
19514.
c. frequency stability
19515.
d. filtering
19516.

19517.
It is a function of component aging and changes in the ambient temperature and
humidity.
19518.
a. short-term stability
19519.
b. damping
19520.
c. long-term stability
19521.
d. filtering
19522.
19523.
It is the study of the form, structure, properties and classifications of crystals
19524.
a. Crystallography
19525.
b. Stalactitomy
19526.
c. Crystallomagraphy
19527.
d. Stalagmitophy
19528.
19529.
It deals with lattices, bonding and behaviour of splices of crystal material that
have been cut at various angles with respect to the crystal’s axes.
19530.
a. Crystallography
19531.
b. Stalactitomy
19532.
c. Crystallomagraphy
19533.
d. Stalagmitophy
19534.
19535.
It occurs when oscillating mechanical stresses applied across a crystal lattice
structure generate electrical oscillations and vice-versa.
19536.
a. crystal effect
19537.
b. photoelectric effect
19538.
c. piezoelectric effect
19539.
d. solar effect
19540.
19541.
Which of the following crystals is commonly used in microphones?
19542.
a. Quartz
19543.
b. Rochelle salt
19544.
c. Tourmaline
19545.
d. ADP
19546.
19547.
Which of the following crystals is often used for frequency control in oscillators?
19548.
a. EDT
19549.
b. Synthetic quartz
19550.
c. Tourmaline
19551.
d. Rochelle salt
19552.
19553.
An increase in temperature causes an increase in frequency and a decrease in
temperature causes an increase in frequency.
19554.
a. negative temperature coefficient
19555.
b. positive temperature coefficient
19556.
c. constant temperature coefficient
19557.
d. temperature coefficient
19558.

19559.
It is a specially constructed diode whose internal capacitance is enhanced when
reverse biased, and by varying the reverse bias voltage, the capacitance of the diode can
be adjusted.
19560.
a. tunnel diode
19561.
b. SAW
19562.
c. backward diode
19563.
d. varactor
19564.
19565.
It is often used when describing varactor diode fabrication.
19566.
a. graded junction
19567.
b. reverse junction
19568.
c. barrier junction
19569.
d. capacitive junction
19570.
19571.
It is an oscillator circuit that generates well-defined, stable waveforms that can be
externally modulated or swept over a given frequency range.
19572.
a. swept generator
19573.
b. frequency synthesizer
19574.
c. wave generator
19575.
d. frequency synchronizer
19576.
19577.
It is a free-running oscillator with a stable frequency of oscillation that depends
on an external timing capacitance, timing resistance, and control voltage.
19578.
a. multiplier
19579.
b. monolithic controlled oscillator
19580.
c. voltage-controlled oscillator
19581.
d. phase-locked loop
19582.
19583.
It is defined as the range of frequencies in vicinity of the VCO’s natural frequency
over which the PLL can maintain lock with an input signal.
19584.
a. capture range
19585.
b. lock range
19586.
c. bandwidth
19587.
d. free-running frequency
19588.
19589.
The voltage-controlled oscillator operates at a set frequency called
19590.
a. free-running frequency
19591.
b. capture range
19592.
c. lock range
19593.
d. bandwidth
19594.
19595.
Free-running frequency is also known as _________.
19596.
a. capture range
19597.
b. lock range
19598.
c. tracking range
19599.
d. natural

19600.
19601.
147. Also known as lock range
19602.
a. capture range
19603.
b. free-running frequency
19604.
c. natural frequency
19605.
d. tracking range
19606.
19607.
148. It is defined as the band of frequencies in the vicinity of the natural
frequency where the
19608.
PLL can establish or acquire lock with an input signal.
19609.
a. tracking range
19610.
b. capture range
19611.c. lock range
19612.
d. hold-in range
19613.
19614.
149. It is an oscillator with stable frequency of oscillation that depends on
an external bias
19615.
voltage.
19616.
a. multiplier
19617.
b. monolithic controlled oscillator
19618.
c. voltage-controlled oscillator
19619.
d. phase-locked loop
19620.
19621.
150. Also known as phase comparator
19622.
a. phase detector
19623.
b. phase-lock loop
19624.
c. voltage controlled oscillator
19625.
d. frequency synthesizer
19626.
19627.
151. It means to form an entity by combining parts or elements.
19628.
a. oscillate
19629.
b. integrate
19630.
c. amplify
19631.
d. synthesize
19632.
19633.
152. It is used to generate many output frequencies through the addition,
subtraction,
19634.
multiplication, and division of a smaller number of fixed frequency
sources.
19635.
a. power amplifier
19636.
b. frequency synchronizer
19637.
c. oscillator
19638.
d. frequency synthesizer
19639.
19640.
153. A type of frequency synthesis in which multiple output frequencies
are generated by
mixing the outputs from two or more crystal-

controlled frequency sources or by dividing
19641.
or multiplying the output frequency form a single-crystal oscillator.
19642.
a. direct frequency synthesis
19643.
b. constant frequency synthesis
19644.
c. indirect frequency synthesis
19645.
d. multiple frequency synthesis
19646.
19647.
154. It is the minimum frequency separation between output frequencies
for the synthesizer.
19648.
a. dynamic range
19649.
b. resolution
19650.
c. octave
19651.
d. decade
19652.
19653.
155. Zero beat is also known as _________.
19654.
a. phase acquisition
19655.
b. loop acquisition
19656.
c. push-in acquisition
19657.
d. frequency acquisition
19658.
19659.
156. Capture range is also known as _________.
19660.
a. pull-in range
19661.
b. lock range
19662.
c. acquisition range
19663.
d. hold-in range
19664.
19665.
157. Half of the lock range is equal to _________.
19666.
a. capture range
19667.
b. hold-in range
19668.
c. pull-in range
19669.
d. free-running frequency
19670.
19671.
158. The _________ gain for a PLL is simply the product of the individual
gains or transfer
19672.
function for the loop.
19673.
a. loop
19674.
b. capture
19675.
c. lock
19676.
d. closed
19677.
19678.
159. Considered as the main source of an internal noise.
19679.
a. Flicker
19680.
b. Thermal agitation
19681.
c. Device imperfection
19682.
d. Temperature change
19683.

19684.
160. What is the first symbol of a radio signal emission having amplitude
modulated main
19685.
carrier?
19686.
a. C
19687.
b. B
19688.
c. H
19689.
d. A
19690.
19691.
161. The method of determining the bandwidth requirements for any
processing system is
19692.
referred to as:
19693.
a. frequency spectrum
19694.
b. frequency analysis
19695.
c. spectral analysis
19696.
d. bandwidth analysis
19697.
19698.
162. When two-equal frequencies are mixed together, the result is
19699.
a. zero-bias
19700.
b. zero-beat
19701.
c. zero-modulation
19702.
d. off-beat
19703.
19704.
163. Noise uniformly distributed over the voice frequency band is called
_________ noise.
19705.
a. impulse
19706.
b. quantizing
19707.
c. intermodulation
19708.
d. white
19709.
19710.
164. In psophometric noise weighting, one picowatt is equivalent to 800
Hz tone with a
19711.
power of
19712.
a. -90 dBm
19713.
b. -85 dBm
19714.
c. -65 dBm
19715.
d. none of the above
19716.
19717.
165. What is the reference tone level for dBa?
19718.
a. -90 dBm
19719.
b. -82 dBm
19720.
c. -67 dBm
19721.
d. -85 dBm
19722.
19723.
166. What is the reference tone level for dBm?
19724.
a. -90 dBm
19725.
b. -82 dBm

19726.
c. -67 dBm
19727.
d. -85 dBm
19728.
19729.
167. At what power level does a 1 kHz tone causes zero interference (144
weighted)?
19730.
a. 90 dB
19731.
b. 90 dBm
19732.
c. -90 dB
19733.
d. -90 dBm
19734.
19735.
168. A tone of _________ Hz causes more interference than do other
frequencies, in a voice
19736.
channel.
19737.
a. 300
19738.
b. 1000
19739.
c. 3400
19740.
d. 4000
19741.
169. A power of a standard test tone is normally _________.
19742.
a. 0 mW
19743.
b. 1 W
19744.
c. 1 dB
19745.
d. 1 mW
19746.
19747.
170. The standard test tone has a frequency of _________ Hz.
19748.
a. 1000
19749.
b. 10
19750.
c. 100
19751.
d. none of these
19752.
19753.
171. In an analog voice frequency channel, the unwanted change in phase
or frequency
19754.
caused by modulation of another signal is;
19755.
a. Intrinsic noise
19756.
b. white noise
19757.
c. intermodulation
19758.
d. phase-jitter
19759.
19760.
172. The kind of noise that is caused by mismatched lines;
19761.
a. echo noise
19762.
b. impulse noise
19763.
c. partition noise
19764.
d. intermodulation noise
19765.
19766.
173. What is the reference tone level for random noise measurement, F1A
weighted?
19767.
a. -90 dBm

19768.
b. -82 dBm
19769.
c. -67 dBm
19770.
d. -85 dBm
19771.
19772.
174. A ten times power change in a transmission system is equivalent to:
19773.
a. 10 dB
19774.
b. 100 dB
19775.
c. 20 dB
19776.
d. 10 dB
19777.
19778.
175. If the transmitter output power of 10 watts is doubled, the gain
derived is about:
19779.
a. 6 dB
19780.
b. 4 dB
19781.
c. 13 dB
19782.
d. noise of the above
19783.
19784.
176. When the power ratio of the input to output is 1/100, the loss of the
circuit, in dB, is
19785.
a. 20
19786.
b. -20
19787.
c. -10
19788.
d. 3
19789.
19790.
177. An antenna which has a power gain of 30 dB would mean it could
increase the output of
19791.
the transmitter by:
19792.
a. 10,000 times
19793.
b. 1,000 times
19794.
c. 100 times
19795.
d. 1 million times
19796.
19797.
178. In a double-tuned circuit, and peak output with _________ coupling.
19798.
a. under
19799.
b. over
19800.
c. optimum
19801.
d. medium
19802.
19803.
179. The frequency band used by cellular telephones and cellular
telephones and mobile
19804.
communication services is _________.
19805.
a. UHF
19806.
b. EHF
19807.
c. VHF
19808.
d. VLF
19809.

19810.
180. The radio wavelength known as _________ falls within the medium
frequency range.
19811.
a. centimetric
19812.
b. decametric
19813.
c. hectometric
19814.
d. myriametric
19815.
19816.
181. In a double-tuned circuit, maximum bandwidth with _________
coupling
19817.
a. under
19818.
b. over
19819.
c. optimum
19820.
d. critical
19821.
19822.
182. Decreasing the Q of a resonant circuit causes its bandwidth to
_________.
19823.
a. increase
19824.
b. decrease
19825.
c. become constant
19826.
d. become narrow
19827.
19828.
183. Most impedance-matching networks are _________ filters, so they
eliminate harmonics.
19829.
a. high-pass
19830.
b. low-pass
19831.
c. bandpass
19832.
d. bandstop
19833.
184. _________ are types of noise generated by equipments that produces
sparks.
19834.
a. equipment noise
19835.
b. atmospheric noise
19836.
c. space noise
19837.
d. internal noise
19838.
19839.
185. A high-frequency noise occurs when the time taken by change
carriers to cross a
19840.
junction is comparable to the period of the signal
19841.
a. pink noise
19842.
b. transit-time noise
19843.
c. white noise
19844.
d. flicker noise
19845.
19846.
186. The electromagnetic spectrum is managed worldwide by the
_________ organization.
19847.
a. FCC
19848.
b. SI

19849.
c. ANSI
19850.
d. ITU
19851.
19852.
187. Unwanted mixer output signals are eliminated by a _________.
19853.
a. filter
19854.
b. multiplexer
19855.
c. mixer
19856.
d. amplifier
19857.
19858.
188. The bandwidth of a double-tuned transformer depends upon the
degree of _________
19859.
between primary and secondary windings.
19860.
a. mutual inductance
19861.
b. coupling coefficient
19862.
c. limiting factor
19863.
d. filtering
19864.
19865.
189. In a double-tuned circuit, minimum bandwidth is obtained with
_________ coupling.
19866.
a. under
19867.
b. over
19868.
c. optimum
19869.
d. critical
19870.
19871.
190. A basic circuit of a frequency of a synthesizer is a _________.
19872.
a. PLL
19873.
b. LC oscillator
19874.
c. Crystal oscillator
19875.
d. RC oscillator
19876.
19877.
191. The output frequency of a synthesizer is changed by varying the
_________ of the
19878.
divider between the VCO and the phase detector.
19879.
a. Mixer output
19880.
b. IF output
19881.
c. Frequency division ratio
19882.
d. Voltage division ratio
19883.
19884.
192. The PLL is often combined with _________ circuits to produce
multiple frequencies.
19885.
a. Local oscillator
19886.
b. Mixer
19887.
c. RF amplifier
19888.
d. AF amplifier
19889.
19890.
193. A crystal oscillator has superior _________ over an LC oscillator.

19891.
a. amplitude stability
19892.
b. frequency stability
19893.
c. phase stability
19894.
d. voltage stability
19895.
19896.
194. If a parallel LC circuit is at resonance, increasing C will cause the
current to _________
19897.
the applied voltage.
19898.
a. lead
19899.
b. lag
19900.
c. lead-lag
19901.
d. lag-lead
19902.
19903.
195. Information sent in the form of coded dots and dashes is called
_________ transmission.
19904.
a. baudot
19905.
b. continuous-wave
19906.
c. digital
19907.
d. any of these
19908.
19909.
196. Fixed-frequency or channel operation of a transmitter is obtained by
using a _________.
19910.
a. LC oscillator
19911.
b. RC oscillator
19912.
c. crystal oscillator
19913.
d. synthesizers
19914.
19915.
197. Combining a feedback capacitor with the internal capacitance of the
transistor forms a
19916.
_________ circuit which is used to cancel the self-oscillation.
19917.
a. filter
19918.
b. tank
19919.
c. bridge
19920.
d. feedback
19921.
19922.
198. Untuned RF transformers permit _________ operation over a wide
frequency range.
19923.
a. narrowband
19924.
b. middleband
19925.
c. broadband
19926.
d. any of these
19927.
19928.
19929.
19930.
19931.

19932.
19933.
19934.
19935.
19936.
19937.
19938.
19939.
19940.
19941.
19942.
19943.
19944.
19945.
19946.
19947.
19948.
19949.
19950.
19951.
19952.
19953.
19954.
19955.
19956.
19957.
19958.
19959.
19960.

19961. MULTIPLE CHOICE QUESTIONS IN

19962. WAVE
PROPAGATION
19963.

Electronics Systems and Technologies
19964. By
19965.

Melvin C. Arceo

19966.
19967.
19968.
19969.
19970.
19971.
19972.
19973.

19974. ENCODED BY:
19975. GARCIA, Virginia Nonna H.
19976.
The cumulative sum of the direct, ground-reflected, and surface waves is reflected
to as _________.
19977. Space wave
19978. Ground wave
19979. Sky wave
19980. Direct waves
19981.
19982.
The D layer of the ionosphere reflects _________ waves.
19983. MF and HF
19984. VLF and MF
19985. MF and VHF
19986. VLF and LF
19987.
19988.
A diversity scheme wherein the same radio signal is repeated or transmitted more
than once.
19989. polarization diversity
19990. field component diversity
19991. time diversity
19992. frequency diversity
19993.
19994.
The disadvantage of ground wave propagation is
19995. Ground waves require a relatively high transmission power
19996. Ground waves are limited to very low, low and medium frequencies requiring
large antennas
19997. Ground losses very considerably with surface material
19998. Any of these
19999.
20000.
A range of microwave frequencies more easily passed by the atmosphere than the
others is called a
20001. window
20002. critical frequency
20003. gyro frequency range

20004. resonance in the atmosphere
20005.
20006.
It is simply the orientation of the electric field vector in respect to the surface of
the Earth
20007. Polarization
20008. Wavefront
20009. Rays
20010. Power density
20011.
20012.
For an isotropic antenna radiating 100W of power, what is power density 1000m
from the source?
20013. 1.99 uW/m^2
20014. 7.96 uW/m^2
20015. 3.22 uW/m^2
20016. 9.17 uW/m^2
20017.
20018.
The ground wave eventually disappears, as moves away from the transmitter,
because of
20019. interference from the sky wave
20020. loss of line-of-sight conditions
20021. maximum single hop distance limitations
20022. tilting
20023.
20024.
If the electric field is propagating parallel to the surface of the Earth, the
polarization is _________.
20025. Circular
20026. Vertical
20027. Horizontal
20028. Elliptical
20029.
20030.
A taxi company uses a central dispatcher, with an antenna at the top of a 15m
tower, to communicate with taxi cabs. The taxi antennas are on the roofs of the cars,
approximately 1.5m above the ground. What is the maximum communication distance
between the dispatcher and a taxi?
20031. 21 km
20032. 30 km
20033. 25 km
20034. 33 km
20035.
20036.
The E layer of the ionosphere aid _________ propagation and reflects _________
waves
20037. MF, HF
20038. HF, MF
20039. LF, MF
20040. MF, LF
20041.

20042.
When microwave signals follows the curvature of the earth, it is known as
20043. the Faraday effect
20044. ducting
20045. tropospheric scatter
20046. ionospheric scatter
20047.
If the polarization vector rotates 360 degrees as the wave moves one wavelength
through space and field strength is equal at all angles of polarization, the polarization is
_________.
20048. Vertically polarized
20049. Horizontally polarized
20050. Circularly polarized
20051. Elliptically polarized
20052.
20053.
_________ travels essentially in a straight line between the transmit and the
receive antennas
20054. Direct waves
20055. Sky waves
20056. Space waves
20057. Surface waves
20058.
20059.
Variations brought about the revolution of the earth around the sun
20060. weather variation
20061. cyclical variation
20062. diurnal variation
20063. seasonal variation
20064.
20065.
The dielectric strength of air is about 3MV/m. Arching is likely to take place at
field strengths greater than that. What is the maximum power density of an
electromagnetic wave in air?
20066. 40 GW/m^2
20067. 15.5 GW/m^2
20068. 23.9 GW/m^2
20069. 18.9 GW/m^2
20070.
20071.
It is a single location from which rays propagate equally in all directions
20072. point source
20073. omnidirectional source
20074. ideal polarization
20075. isotropic polarized
20076.
20077.
Diffraction of electromagnetic waves
20078. is caused by reflections from the ground
20079. arises only with spherical waveforms
20080. will occur when the waves pass through a large slot
20081. may occur around the edge of a sharp obstacle
20082.
The critical frequency at a particular time is 11.6MHz. What is the MUF for a

transmitting station if the required angle of incidence for propagation to a desired
destination is 70 degrees?
20083. 34 MHz
20084. 45 MHz
20085. 40 MHz
20086. 15.5 MHz
20087.
20088.
The rate at which energy passes through a given surface area in free space is
called _________.
20089. capture power
20090. capture area
20091. captured power density
20092. power density
20093.
20094.
A radio wave moves from air (relative permittivity is 1) to glass (relative
permittivity is 7.8). Its angle of incidence is 30 degrees. What is the angle of refraction?
20095. 10.3 degrees
20096. 11.2 degrees
20097. 20.4 degrees
20098. 0.179 degrees
20099.
20100.
It is the intensity of the electric and the magnetic fields of the electromagnetic
wave propagating in free space
20101. field intensity
20102. field density
20103. power intensity
20104. power intensity
20105.
20106.
Radio propagation was predicted mathematically by
20107. Heinrich R. Hertz
20108. Guglielmo Marconi
20109. James Clerk Maxwell
20110. Alexander Graham Bell
20111.
20112.
Tropospheric scatter is used with frequencies in the following range
20113. HF
20114. VHF
20115. UHF
20116. VLF
20117.
A point source that radiates power at a constant rate uniformly in all directions.
20118. isotropic source
20119. isotropic radiator
20120. point source
20121. any of these
20122.
20123.
The transmitting distance with direct waves is limited to short distances and

strictly a function of the _________ of the transmitting and receiving antenna.
20124. frequency
20125. phase
20126. power
20127. height
20128.
20129.
One nautical mile is equal to _________ statute miles.
20130. 2.12
20131. 1.15
20132. 2.54
20133. 1.90
20134.
20135.
It is the deflection or bending of electromagnetic waves such as radio waves, light
or even sound when the waves cross the boundary line between two mediums with
different characteristics.
20136. reflection
20137. diffraction
20138. refraction
20139. dispersion
20140.
20141.
The reduction of power density with distance is equivalent to a power loss.
20142. absorption
20143. attenuation
20144. distance loss
20145. power dissipation
20146.
20147.
The signal refracted back from the ionosphere strikes the earth and is reflected
back up to the ionosphere again to be bent and sent back to earth.
20148. skip transmission
20149. multi-hop transmission
20150. multi transmission
20151. hop transmission
20152.
20153.
Electromagnetic waves are refracted when they
20154. pass into a medium of different dielectric constant
20155. are polarized at right angles to the direction of propagation
20156. encounter a perfectly conducting surface
20157. pass through a small slot in a conducting plane
20158.
20159.
The reduction in power density due to nonfree-space propagation
20160. absorption
20161. attenuation
20162. power dissipation
20163. distance loss
20164.
20165.
_________ is the signal that is radiated by the antenna into the atmosphere where

it is bent or reflected back to earth.
20166. ground wave signal
20167. sky wave signal
20168. space wave signal
20169. direct waves signal
20170.
20171.
It is a type of fading having different effect different frequencies
20172. Selective fading
20173. Polarization fading
20174. Interference fading
20175. Absorption fading
20176.
20177.
It is defined as the modulation or redistribution of energy within a wave front as it
passes near the edge of an opaque object.
20178.
a. refraction
20179.
b. scattering
20180.
c. reflection
20181.
d. diffraction
20182.
20183.
What type of modulation is primarily used in ground wave propagation?
20184. Frequency modulation
20185. Amplitude modulation
20186. Phase modulation
20187. Pulse modulation
20188.
20189.
It states that every point on a given spherical wavefront can be considered as a
secondary point source of electromagnetic waves from which other secondary waves or
wavelets are radiated outward.
20190. Hertzian principle
20191. Maxwell’s principle
20192. Huygen’s principle
20193. Marconi’s principle
20194.
20195.
Calculate the electric field intensity, in volts per meter, 20 km from a 1-kW
source.
20196. 3.44 mW/m
20197. 7.65 mW/m
20198. 8.66 mW/m
20199. 1.45 mW/m
20200.
20201.
The absorption of radio waves by the atmosphere depends on
20202. their frequency
20203. their distance from the transmitter
20204. the polarization of waves
20205. is always vertical in an isotropic medium
20206.

20207.
Calculate the radio horizon for a 500-ft transmitting antenna and receiving
antenna of 20 ft.
20208. 23.1 mi
20209. 31.2 mi
20210. 14.8 mi
20211. 37.9 mi
20212.
20213.
Calculate the power received from a 20-W transmitter, 22,000 miles from earth, if
the receiving antenna has an effective area of 1600m^2
20214. 4.06 x 10^-12 W
20215. 2.03 x 10^-12 W
20216. 1.02 x 10^-12 W
20217. 0.91 x 10^-12 W
20218.
20219.
As electromagnetic waves travel in free space, only one of the following can
happen to them
20220. absorption
20221. attenuation
20222. refraction
20223. reflection
20224.
Electromagnetic waves travelling within Earth’s atmosphere is called
20225. Space wave
20226. Surface wave
20227. Terrestrial wave
20228. Sky-wave
20229.
20230.
Calculate the power density in watts per square meter (on earth) from a 10-W
satellite source that is 22,000 miles from earth.
20231. 3.17 x 10^ -16 W/m^2
20232. 6.35 x 10^ -16 W/m^2
20233. 2.31 x 10^ -16 W/m^2
20234. 1.21 x 10^ -16 W/m^2
20235.
20236.
It is termed used to describe variations in signal strength that occur at the receiver
during this time a signal is being received.
20237. skipping
20238. attenuation
20239. absorption
20240. fading
20241.
20242.
The constant temperature stratosphere is called _________.
20243. E-layer
20244. S-layer
20245. isothermal region
20246. ionosthermal region
20247.

20248.
It is the tendency of the sun to have grayish-black blemishes, seemingly at
random times and at random place, on its fiery surface.
20249. solar intensity
20250. sunspot
20251. solar flare
20252. solar flux
20253.
20254.
In electromagnetic waves, polarization
20255. is caused by reflection
20256. is due to the transverse nature of the waves
20257. results from the longitudinal nature of waves
20258. is always vertical in an isotropic medium
20259.
20260.
It is an earth-guided electromagnetic wave that travels over the surface of the
Earth
20261. Surface waves
20262. Sky waves
20263. Direct waves
20264. Space waves
20265.
20266.
Frequencies in the UHF range normally propagate by means of
20267. Ground waves
20268. Sky waves
20269. Surface waves
20270. Space waves
20271.
20272.
The curvature of the Earth presents a horizon to space wave propagation
commonly called _________.
20273. Optical horizon
20274. Radio horizon
20275. Horizontal horizon
20276. Vertical horizon
20277.
20278.
Electromagnetic waves that are directed above the horizon level is called
_________.
20279. direct waves
20280. sky waves
20281. space waves
20282. surface waves
20283.
20284.
The refracting and reflecting action of the ionosphere and the ground is called
20285. sliding
20286. skipping
20287. hopping
20288. boosting
20289.

20290.
An electrical energy that is escaped in free space
20291. Electrical signal
20292. Electromagnetic waves
20293. Magnetic waves
20294. Electromagnetism
20295.
20296.
The layer of the ionosphere which farthest from the sun
20297. D layer
20298. E layer
20299. F1 layer
20300. F2 layer
20301.
20302.
A condition which manifest itself in the form of double-image distortion
20303. running
20304. fading
20305. ghosting
20306. snowing
20307.
20308.
The D layer of the ionosphere absorbs _________ waves.
20309. LF and MF
20310. MF and HF
20311. HF and VHF
20312. VHF and UHF
20313.
20314.
The E layer of the ionosphere is sometimes called _________
20315. Kennely-Heavisides
20316. Sporadic-E layer
20317. E-densed layer
20318. Kennely layer
20319.
20320.
It is defined as the higher frequency that can be propagated directly upward and
still be returned to earth by the ionosphere
20321. critical angle
20322. maximum usable frequency
20323. critical frequency
20324. virtual height
20325.
20326.
The maximum vertical angle at which electromagnetic waves can be propagated
and still be reflected back by the ionosphere
20327. numerical aperture
20328. incident angle
20329. critical angle
20330. refracted angle
20331.
20332.
It is defined as the plane joining all points of equal phase
20333. rays

20334. electromagnetic wave
20335. wavefront
20336. isotropic source
20337.
20338.
It is the height above Earth’s surface from which a reflected wave appears to have
been reflected.
20339. virtual height
20340. maximum height
20341. vertical height
20342. horizontal height
20343.
20344.
It is the highest frequency that can be used for sky wave propagation between two
specific points on Earth’s surface
20345. optimum working frequency
20346. maximum usable frequency
20347. critical frequency
20348. maximum frequency
20349.
20350.
The polarization of electromagnetic waves can be determined by the direction of
the
20351. E field
20352. H field
20353. propagation
20354. both E and H field
20355.
20356.
85 percent of the maximum usable frequency (MUF) is called _________.
20357. maximum usable frequency
20358. optimum working frequency
20359. critical frequency
20360. maximum frequency
20361.
20362.
It is defined as the minimum distance from the transmit antenna that a sky wave at
a given frequency will be returned to earth.
20363. skip distance
20364. skip zone
20365. skip frequency distance
20366. skip zone frequency
20367.
20368.
At distance greater than the skip distance, two rays can take different paths and
still be returned to the same point on Earth. The two rays are called lower rays and
_________.
20369. Pedersen ray
20370. Light ray
20371. Huygen’s ray
20372. Miller’s ray
20373.

20374.
Undesired radiated energy from a radio transmitter or in another source.
20375. ESD
20376. EMI
20377. RFI
20378. ESI
20379.
20380.
The area between where the surface waves are completely dissipated and the point
where the first sky wave returns to earth is called _________.
20381. skip distance
20382. skip distance zone
20383. optical horizon
20384. quiet zone
20385.
20386.
The undesired radiated energy that may cause interference with other electronic
equipment in the vicinity.
20387. ESD
20388. EMI
20389. RFI
20390. ESI
20391.
20392.
It is defined as the loss incurred by an electromagnetic wave as it propagates in a
straight line through a vacuum with no absorption or reflection of energy from nearby
objects.
20393. free-space path loss
20394. free space loss
20395. path loss
20396. any of these
20397.
20398.
To increase the transmission distance of a UHF signal, which of the following
should be done?
20399. increase the antenna gain
20400. increase antenna height
20401. increase transmitter power
20402. increase receiver sensitivity
20403.
20404.
For a carrier frequency of 6 GHz and a distance of 50 km, determine the freespace path loss
20405. 132 dB
20406. 123 dB
20407. 142 dB
20408. 152 dB
20409.
A microwave-transmitting antenna is 550 ft high. The receiving antenna is 200 ft
high. The maximum transmission distance is
20410. 20 mi
20411. 33.2 mi
20412. 38.7 mi

20413. 53.2 mi
20414.
20415.
Indicate which one of the following term applies to troposcatter propagation
20416. SIDs
20417. Fading
20418. Atmospheric storms
20419. Faraday’s rotation
20420.
20421.
Line-of-sight communications is not a factor in which frequency range?
20422. VHF
20423. UHF
20424. HF
20425. Microwave
20426.
20427.
VLF waves are used for some types of services because
20428. of the low powers required
20429. the transmitting antenna are of convenient size
20430. they are very reliable
20431. affected by the solar cycle
20432.
20433.
Microwave signals propagate by way of the
20434. direct wave
20435. sky wave
20436. surface wave
20437. standing wave
20438.
20439.
Indicate which of the following frequencies cannot be used for reliable beyondthe-horizon terrestrial communications without repeaters:
20440. 20 kHz
20441. 15 MHz
20442. 900 MHz
20443. 12 GHz
20444.
20445.
The type of radio wave responsible for long-distance communications by multiple
skips is the
20446. ground wave
20447. direct wave
20448. surface waves
20449. sky wave
20450.
20451.
High-frequency waves are
20452. absorbed by the F2 layer
20453. reflected by the D layer
20454. capable of use for long-distance communications on the moon
20455. affected by the solar cycle
20456.

20457.
The ionosphere has its greatest effect on signals in what frequency range?
20458. 300 kHz to 3 MHz
20459. 3 to 30 MHz
20460. 30 to 300 MHz
20461. above 300 MHz
20462.
20463.
Distances near the skip distance should be used for sky-wave propagation
20464. to avoid tilting
20465. to prevent sky-wave and upper ray interference
20466. to avoid Faraday effect
20467. so as not to exceed the critical frequency
20468.
20469.
Ground-wave communications is most effective in what frequency range?
20470. 300 kHz to 3 MHz
20471. 3 to 30 MHz
20472. 30 to 300 MHz
20473. above 300 MHz
20474.
20475.
The ionosphere causes radio signals to be
20476. diffused
20477. absorbed
20478. refracted
20479. reflected
20480.
20481.
Helical antenna are often used for satellite tracking at VHF because of
20482. troposcatter
20483. superrefraction
20484. ionospheric refraction
20485. the Faraday effect
20486.
A ship-to-ship communication system is plagued by fading. The best solution
seem to use of
20487. a more directional antenna
20488. a broadband antenna
20489. frequency diversity
20490. space diversity
20491.
20492.
It is defined as the ratio of the electric field intensity of the reflected wave to that
of the incident wave
20493. refractive index
20494. numerical aperture
20495. reflection coefficient
20496. absorption coefficient
20497.
20498.
It is the measure of energy received per unit time, per unit area, per unit frequency
interval.
20499. solar intensity

20500. sunspot
20501. solar flare
20502. solar flux
20503.
20504.
A long period with lack of any solar activity
20505. El Niño
20506. La Niña
20507. Maunder period
20508. Sunspots
20509.
20510.
As a ground-wave signal moves away from the transmitter, the ground wave
eventually disappears due to the
20511. absorption
20512. tilting
20513. refraction
20514. diffraction
20515.
20516.
It is the lowest layer of the atmosphere where all weather disturbances takes place
20517. D layer
20518. Stratosphere
20519. Ionosphere
20520. Troposphere
20521.
20522.
It is the lower limit of the range of frequencies that provide useful communication
between two given points by the way of the ionosphere.
20523. MUF
20524. LUF
20525. OWF
20526. MMF
20527.
20528.
It is the area that lies between the outer limit of the ground-wave range and the
inner edge of energy return from the ionosphere
20529. skip distance
20530. skip zone
20531. virtual height
20532. optical horizon
20533.
20534.
Variations brought about by the rotation of the earth around its axis.
20535. cyclical rotation
20536. seasonal variation
20537. diurnal variation
20538. weather variation
20539.
20540.
Ionospheric irregularity caused by solar flares, which are gigantic emissions of
hydrogen from the sun.
20541. Sudden ionospheric disturbances

20542. Dillenger fadeouts
20543. Mogul-Delliger fadeouts
20544. Any of these
20545.
20546.
It is a type of fading caused by so-called Faraday effect or Faraday rotation
20547. interference fading
20548. absorption fading
20549. selective fading
20550. polarization fading
20551.
20552.
Radio horizon is _________ greater than the optical horizon.
20553. one-third
20554. four-third
20555. two-third
20556. twice
20557.
20558.
An increase in temperature with height which gives rise to superrefraction or
ducting is known as _________.
20559. height inversion
20560. depth inversion
20561. temperature inversion
20562. ionospheric inversion
20563.
20564.
A region in which superrefraction occurs which is formed in the troposphere when
the
20565.
layer of cool air becomes trapped underneath a layer of warmer air.
20566.
a. duct
20567.
b. dielectric area
20568.
c. gateway
20569.
d. window
20570. 101. A range of frequency little attenuated by the atmosphere is called
20571.
a. slide
20572.
b. door
20573.
c. window
20574.
d. frame
20575.
20576.
102. It is defined as either of two acute angles formed by the intersection of the
two portions
of the tropospheric scatter beam tangent to the earth’s surface.
20577.
a. critical angle
20578.
b. scatter angle
20579.
c. backscatter angle
20580.
d. sidescatter angle
20581.
20582. 103. It is a device that permits two different transmitters to operate with a single
antenna
20583.
a. duplexer

20584.
b. diplexer
20585.
c. isolator
20586.
d. circulator
20587.
20588. 104. It is a gradual shift in polarization of the signal in the medium.
20589.
a. fading
20590.
b. faraday effect
20591.
c. ghosting
20592.
d. multipath fading
20593.
20594. 105. A diversity scheme wherein the receiver receives two fading signals from two
different
20595.
directions
20596.
frequency diversity
20597.
time diversity
20598.
angle diversity
20599.
space diversity
20600. 106. The radio wavelength known as _________ falls within the medium frequency
range
20601.
a. centimetric wave
20602.
b. decametric wave
20603.
c. hectometric wave
20604.
d. myriametric wave
20605.
20606. 107. The most dense of all ionized layer of the ionosphere
20607.
a. E
20608.
b. F1
20609.
c. F2
20610.
d. D
20611.
20612. 108. The frequency band used as sub-carriers, or signals which carry the baseband
modulating information but in turn modulate another higher-frequency carrier is
_________.
20613. a. LF
20614. b. MF
20615. c. VLF
20616. d. VH
20617.
20618. 109. The range of frequency band termed as super high frequency (SHF) is within
_________.
20619. a. 30-300 GHz
20620. b. 30-300 MHz
20621. c. 3-30 GHz
20622. d. 300-3000 MHz
20623.
20624. 110. Electric field that lies in a plane perpendicular to the earth’s surface.

20625. a. circular polarization
20626. b. vertical polarization
20627. c. horizontal polarization
20628. d. elliptical polarization
20629.
20630. 111. The magnetic field of an antenna is perpendicular to the earth. The antenna’s
polarization
20631. a. is vertical
20632. b. is horizontal
20633. c. is circular
20634. d. cannot be determined from the information given
20635.
20636. 112. The surface wave is effective only at frequencies below about _________ MHz.
20637. a. 30
20638. b. 3
20639. c. 300
20640. d. 0.3
20641.
20642. 113. What wave propagation are attenuated within a few miles?
20643. a. space
20644. b. sky
20645. c. ground
20646. d. direct
20647.
20648. 114. What happens to wave velocity as it passes from air to ionosphere?
20649. a. increases
20650. b. decreases
20651. c. remain the same
20652. d. not a factor
20653.
20654. 115. What wavelength radiations tend to be transmitted entirely between ionosphere and
earth?
20655. a. long
20656. b. short
20657. c. medium
20658. d. millimeter
20659.
20660. 116. What effect do sunspots have on the ionosphere?
20661. a. makes more rare and regular
20662. b. makes more dense and irregular
20663. c. makes less dense and regular
20664. d. makes less dense and irregular
20665.
20666. 117. What is a double-hop signal?
20667. a. ground, ionosphere, ground and back to ionosphere
20668. b. ground, ground, ionosphere, and ionosphere

20669. c. ionosphere, ionosphere, ground and ground
20670. d. ionosphere, ground, ionosphere and back to ground
20671.
20672. 118. What is the major cause of fading?
20673. a. phase difference
20674. b. topographic variation
20675. c. climate
20676. d. ionosphere variation
20677.
20678. 119. Where is the skip zone?
20679. a. between the sky and the first reflected wave
20680. b. between end of ground and first reflected wave
20681. c. between end of ground and farthest reflected wave
20682. d. between the end of sky to the farthest reflected wave
20683.
20684.
120. What wave is the same day or night?
20685.
a. sky
20686.
b. space
20687.
c. direct
20688.
d. ground
20689.
20690.
121. Why do HF communications system shift frequencies at different
times of day?
20691.
a. to take advantage of best reflected signals
20692.
b. to conserve the energy used
20693.
c. to create diversity
20694.
d. to improve noise performance
20695.
20696.
122. Scatter transmission is used at what frequencies?
20697.
a. EHF and VLF
20698.
b. HF and VHF
20699.
c. VHF and UHF
20700.
d. ELF and VLF
20701.
20702.
123. Over what areas ducts often form?
20703.
a. desert
20704.
b. water
20705.
c. forest
20706.
d. mountain
20707.
20708.
124. Polarization named for _________ component of the wave?
20709.
a. static
20710.
b. magnetic
20711.
c. direction
20712.
d. propagation
20713.

20714.
20715.
20716.
20717.
20718.
20719.
20720.
20721.

125. What polarization is employed in an AM broadcasting?
a. horizontal
b. parallel
c. transverse
d. vertical

20722.
20723.
20724.
20725.
20726.
20727.
20728.
20729.
20730.
20731.

20732. MULTIPLE CHOICE QUESTIONS IN

20733. DIGITAL AND
DATA
COMMUNICATIONS
20734.

Electronics Systems and Technologies
20735. By
20736.

Melvin C. Arceo
20737.
20738.

20739.
20740.
20741.
20742.
20743.

20744. ENCODED BY:
20745. GIRAO, Edward Joseph D.

20746.

1. It is defined as knowledge or intelligence that is communicated between two or
more points.
20747. A. Carrier
20748.
B. Sideband
20749.
C. Information
20750.
D. Broadband
20751.
2. What is the category of data transmission if the binary pulse is maintained for
the entire bit time?
20752. A. Return to zero
20753.
B. Bipolar
20754.
C. Unipolar
20755.
D. Non return to zero
20756.
3. Which medium is most widely used in LANs?
20757. A. Twin lead
20758.
B. Fiber-optic cable
20759.
C. Twisted pair
20760.
D. Coax
20761.
4. These are used for transmission of PCM encoded time-division multiplexed
digital signal
20762. A. I carriers
20763.
B. E carriers
20764.
C. A carriers
20765.
D. T carriers
20766.
5. Which of the following is not a typical FDM application?
20767. A. telemetry
20768.
B. stereo broadcasting
20769.
C. telephone
20770.
D. secure communications
20771.
6. A LAN device that use to interconnect two networks that use different protocols
and formats
20772. A. Gateways
20773.
B. Routers
20774.
C. Bridges
20775.
D. Hubs
20776.
7. A pulse modulation technique as the width of a constant amplitude pulse is
varied proportional to the amplitude of the analog signal at the time the signal is sampled.
20777. A. Pulse Width Modulation
20778.
B. Pulse Length Modulation
20779.
C. Pulse Duration Modulation
20780.
D. All of these
20781.
8. The FDM telephone systems accommodate many channels by
20782. A. Increasing the multiplexer size
20783.
B. Using many final carriers
20784.
C. Narrowing the bandwidth of each
20785.
D. Using multiple levels of multiplexing
20786.
9. It is the transmittal of digitally modulated analog signals (carrier) between two

or more points in a communications system.
20787. A. Digital Modulation
20788.
B. Digital Transmission
20789.
C. Digital Communications
20790.
D. Pulse Modulation
20791.
10. Indicate which of the following systems is digital
20792. A. Pulse-position modulation
20793.
B. Pulse-code modulation
20794.
C. Pulse-width modulation
20795.
D. Pulse-frequency modulation
20796.
11. Classification of protocol that interprets a frame of data as a group of
successive bit combined into predetermined pattern of fixed length, usually 8 bits each.
20797. A. Character-oriented protocols
20798.
B. Byte-oriented protocols
20799.
C. Bit-oriented protocol
20800.
D. Character and Byte-oriented protocols
20801.
12. Dividing the data block by a constant produces a remainder that is used for
error detection. It is called the
20802. A. Vertical redundancy checking
20803.
B. Horizontal redundancy checking
20804.
C. Block check character
20805.
D. Cyclic redundancy check
20806.
13. Which of the following is not a benefit of spread spectrum?
20807. A. Jam-proof
20808.
B. Security
20809.
C. Immunity to fading
20810.
D. Noise proof
20811.
14. Converting analog signals to digital is done by sampling and _________.
20812. A. quantizing
20813.
B. companding
20814.
C. pre-emphasis
20815.
D. mixing
20816.
15. It is a process of converting an infinite number of possibilities to a finite
number of conditions
20817. A. Sampling
20818.
B. Coding
20819.
C. Quantization
20820.
D. Aliasing
20821.
16. In T1, it is equal to the reciprocal of the sample rate
20822. A. Slot time
20823.
B. Transmission time
20824.
C. Frame time
20825.
D. Bit rate
20826.
17. What is the final output of a multiplexer?
20827. A. Baseband
20828.
B. Composite baseband

20829.
C. Information
20830.
D. Composite carrier
20831.
18. The baud rate
20832. A. is always equal to the bit transfer rate
20833.
B. is equal to the twice the bandwidth of an ideal channel
20834.
C. is not equal to the signaling rate
20835.
D. is equal to one-half the bandwidth of an ideal channel
20836.
19. Bit errors in data transmission are usually caused by
20837. A. equipment failures
20838.
B. typing mistakes
20839.
C. noise
20840.
D. Poor S/N ratio at receiver
20841.
20. A digital modulation technique which is a form of constant-amplitude angle
modulation similar to standard frequency modulation except the modulating signal is
binary signal that varies between two discreet voltage levels.
20842. A. QAM
20843.
B. ASK
20844.
C. PSK
20845.
D. FSK
20846.
21. Start and stop bits, respectively, are
20847. A. Mark, space
20848.
B. Space, mark
20849.
C. Space, space
20850.
D. Mark, mark
20851.
22. It is the processing of analog signals using digital methods and includes
bandlimiting and signals with filters, amplitude equalization, and phase shifting
20852. A. Digital communications
20853.
B. Digital signal processing
20854.
C. Data communications
20855.
D. Carrier recovery method
20856.
23. It is a network access method used primarily with LANs configured in a ring
topology using either baseband or broadband transmission formats.
20857. A. Ethernet
20858.
B. Token passing
20859.
C. Token ring
20860.
D. Token bus
20861.
24. A small telephone switching system that can be used as a LAN is called
20862. A. Ring
20863.
B. WAN
20864.
C. UART
20865.
D. PBX
20866.
25. The most common method used for sampling voice signals in PCM systems.
20867. A. unnatural sampling
20868.
B. flat top smpling
20869.
C. natural sampling
20870.
D. free sampling

20871.
26. In PCM, it converts the PAM samples to parallel PCM codes
20872. A. Analog-to-digital Converter
20873.
B. Digital-to-analog Converter
20874.
C. Pre-emphasis circuit
20875.
D. Compander
20876.
27. The OSI layer that provides the control functions necessary to establish
manage, and terminate the connections as required to satisfy the user request.
20877. A. Application layer
20878.
B. Network layer
20879.
C. Session layer
20880.
D. Physical layer
20881.
28. In PAM demultiplexing, the receiver clock is derived from
20882. A. standard radio station WWW
20883.
B. a highly accurate internal oscillator
20884.
C. the PAM signal itself
20885.
D. the 60-Hz power line
20886.
29. It is also known as digital modulation
20887. A. digital transmission
20888.
B. digital sampling
20889.
C. digital radio
20890.
D. data transmission
20891.
30. Time-division multiplex
20892. A. can be used with PCM only
20893.
B. combines five groups into a supergroup
20894.
C. stacks 24 channels in adjacent frequency slots
20895.
D. interleaves pulses belonging to different transmissions
20896.
31. It is a numerical indication of how efficiently a PCM code is utilized
20897. A. Coding efficiency
20898.
B. Companding
20899.
C. Pre-emphasis
20900.
D. Dynamic Range
20901.
32. Type of PCM which is designed to take advantage of the sample-to sample
redundancies in the typical speech waveform
20902. A. Single-bit PCM code
20903.
B. Pulse code modulation
20904.
C. Differential PCM
20905.
D. Data modulation
20906.
33. The Basic Rate Interference (BRI) of ISDN has a total bit rate of ______
20907. A. 192 kbps
20908.
B. 148 kbps
20909.
C. 64 kbps
20910.
D. 1.544 Mbps
20911.
34. A form of angle-modulated, constant amplitude digital modulation similar to
conventional phase modulation except its input is binary digital signal and there are
limited number of output phase possible
20912. A. ASK

20913.
B. PSK
20914.
C. FSK
20915.
D. QAM
20916.
35. The main circuit in a PSN generator is
20917. A. XOR
20918.
B. Multiplexer
20919.
C. Shift register
20920.
D. Mixer
20921.
36. The circuit that performs demultiplexing in an FDM is _____
20922. A. Op-amp
20923.
B. Bandpass filter
20924.
C. Discriminator
20925.
D. Subcarrier oscillator
20926.
37. _____ defines how a user gets control of the channel so as to allow
transmission.
20927. A. channel access
20928.
B. collision detection
20929.
C. collision avoidance
20930.
D. carrier sense
20931.
38. The fastest LAN topology is
20932. A. ring
20933.
B. bus
20934.
C. star
20935.
D. square
20936.
39. It is a theoretical expectation of the bit error rate in the system
20937. A. probability of errors
20938.
B. error detection
20939.
C. error control
20940.
D. bit error rate
20941.
40. It is simply the data rate at which serial PCM bits are clocked out of the PCM
encoder onto the transmission line.
20942. A. line speed
20943.
B. baud rate
20944.
C. output rate
20945.
D. bit rate
20946.
41. A quantizing is _____
20947. A. Multiplexer
20948.
B. Demultiplexer
20949.
C. A/D converter
20950.
D. D/A converter
20951.
42. Refers to the rate of change of a signal on a transmission medium after
encoding and modulation have occurred
20952. A. baud rate
20953.
B. phase shift
20954.
C. bit rate
20955.
D. frequency deviation

20956.
43. The magnitude difference between adjacent steps in quantization is called
_____
20957. A. Quantum
20958.
B. Step size
20959.
C. Resolution
20960.
D. Any of these
20961.
44. It is a set of rules implementing and governing an orderly exchange of data
between layers of two devices, such as line control units and front-end processors.
20962. A. Data Link Protocol
20963.
B. Network Protocol
20964.
C. Pont to Point Protocol
20965.
D. File Transfer Protocol
20966.
45. A signaling system in which each letter of the alphabet is represented by a
different symbol is not used because
20967. A. it would be too difficult for an operator to memorize
20968.
B. it is redundant
20969.
C. noise would introduce too many errors
20970.
D. too many pulses per letter are required
20971.
46. A modulation process that involves conversion of a waveform from analog to
digital form by means of coding
20972. A. PDM
20973.
B. PCM
20974.
C. PLM
20975.
D. PAM
20976.
47. What is the bandwidth required to transmit at a rate of 10 Mbps in the
presence of a 28-Db S/N ratio?
20977. A. 1.075 MHz
20978.
B. 10 MHz
20979.
C. 5 MHz
20980.
D. 10.75 MHz
20981.
48. The slope of the analog signal is greater than the delta modulator can maintain
20982. A. overload distortion
20983.
B. granular noise
20984.
C. slope overload
20985.
D. peak limiting
20986.
49. A scheme in which several channels are interleaved and then transmitted
together is known as
20987. A. frequency division multiplex
20988.
B. time-division multiplex
20989.
C. a group
20990.
D. a supergroup
20991.
50. The best frequency demodulator is
20992. A. PLL discriminator
20993.
B. Pulse-averaging discriminator
20994.
C. Foster-Seeley discriminator
20995.
D. Ratio detector

20996.
51. What property distinguishes digital radio systems from conventional analog
communications system?
20997. A. the type of carrier used in transmission of data
20998.
B. the nature of the modulating signal
20999.
C. the type of modulation of data to be used
21000.
D. the nature of the transmitter and receiver to be used
21001.
52. The circuit switch is a _____ switch.
21002. A. See-through
21003.
B. Transparent
21004.
C. Vague
21005.
D. Opaque
21006.
53. A carrier recovery circuit is not needed with
21007. A. FSK
21008.
B. BPSK
21009.
C. DPSK
21010.
D. QAM
21011.
54. The Hartley-Shannon theorem sets a limit on the
21012. A. the highest frequency that may be sent over a given channel
21013.
B. maximum capacity of a channel with a given noise level
21014.
C. maximum number of coding levels in a channel with a given noise level
21015.
D. maximum number of quantizing levels in a channel of a given
bandwidth
21016.
55. The phase relationship between signaling elements for BPSK is the optimum
signaling format and occurs only when two binary signal levels are allowed and when
one signal is the exact negative of the other
21017. A. Antipodal signaling
21018.
B. Carrier recovery
21019.
C. Squaring loop
21020.
D. Phase referencing
21021.
56. Pulse-amplitude modulation signals are multiplexed by using
21022. A. Subcarrier
21023.
B. Bandpass filters
21024.
C. A/D Converters
21025.
D. FET switches
21026.
57. It is the ratio of the transmission bit rate to the minimum bandwidth required
for a particular modulation scheme.
21027. A. Bandwidth efficiency
21028.
B. All of these
21029.
C. Information density
21030.
D. Spectral efficiency
21031.
58. Ethernet is a baseband transmission system designed by _____
21032. A. Thomas Murray and Robert Metcalfe
21033.
B. David Boggs and Thomas Murray
21034.
C. Thomas Murray and Emile Baudot
21035.
D. Robert Metcalfe and David Boggs
21036.
59. It is a system where the digital signals are placed directly on the coaxial cable.

21037. A. Broadband
21038.
B. Baseband
21039.
C. CSMA/CD
21040.
D. Token ring
21041.
60. A basic group B
21042. A. occupies the frequency range from 60 to 108 kHz
21043.
B. consists of erect channels only
21044.
C. is formed at the group translating equipment
21045.
D. consists of five supergroups
21046.
61. Which of the following is not primarily a type of data communications?
21047. A. telephone
21048.
B. teletype
21049.
C. telegraph
21050.
D. CW
21051.
62. Packets which is self-contained and travels through the network independent
of other packets of the same message by whatever means available.
21052. A. Packet
21053.
B. Frame
21054.
C. Datagram
21055.
D. Data
21056.
63. Transmitting the data signal directly over the medium is referred to as
21057. A. baseband
21058.
B. broadband
21059.
C. ring
21060.
D. bus
21061.
64. The main reason that serial transmission is preferred to parallel transmission is
that?
21062. A. serial is faster
21063.
B. serial requires only a single channel
21064.
C. serial requires multiple channels
21065.
D. parallel is too expensive
21066.
65. Which of the following is not a LAN?
21067. A. PBX system
21068.
B. Hospital system
21069.
C. Office building system
21070.
D. Cable TV system
21071.
66. A modulation technique where data rates in excess of 56 kbps can be achieved
over telephone circuits
21072. A. ASK
21073.
B. Trellis code modulation
21074.
C. GSK
21075.
D. any of these
21076.
67. It is how the primary designates the secondary as a designation or recipient of
data.
21077. A. Line turnaround
21078.
B. Selection

21079.
C. Line control
21080.
D. Control protocol
21081.
68. It is the process of compressing and expanding and is a means of improving
the dynamic range of a communications system.
21082. A. Pre-emphasis
21083.
B. Filtering
21084.
C. De-emphasis
21085.
D. Companding
21086.
69. The supergroup pilot is
21087. A. applied at each multiplexing bay
21088.
B. used to regulate the gain of individual repeaters
21089.
C. applied at each adjustable equalizer
21090.
D. fed in at a GTE
21091.
70. The time it takes to transmit one TDM frame is called _____
21092. A. Slot time
21093.
B. Frame time
21094.
C. Transmission time
21095.
D. any of these
21096.
71. It is the thermal noise power normalized to 1-Hz bandwidth
21097. A. power density ratio
21098.
B. thermal noise
21099.
C. noise power density
21100.
D. ambient temperature noise
21101.
72. It is the procedure used to decide which device has the permission to transmit
at any given time.
21102. A. Flow control
21103.
B. Sequence control
21104.
C. Line control
21105.
D. Frame
21106.
73. Any rounded-off errors in the transmitted signal are reproduced when the code
is converted back to analog in the receiver
21107. A. Aperture error
21108.
B. Quantization error
21109.
C. Aperture distortion
21110.
D. Slope overload
21111.
74. The biggest disadvantage of PCM is
21112. A. its inability to handle analog signals
21113.
B. the high error rate which is quantizing noise introduces
21114.
C. its incompatibility with TDM
21115.
D. the large bandwidths that are required for it
21116.
75. T1 stands for
21117. A. Transmission one
21118.
B. Telecommunication one
21119.
C. Telex one
21120.
D. Transmission line one
21121.
76. Involves compression in the transmitter after the input pulse has been

converted to a linear PCM code and then expansion in the receiver prior to PCM coding
21122. A. analog companding
21123.
B. A-law companding
21124.
C. digital companding
21125.
D. u-law companding
21126.
77. Mark and space refer respectively to
21127. A. dot and dash
21128.
B. message and interval
21129.
C. binary 1 and binary 0
21130.
D. on and off
21131.
78. Variation of biphase that is used for encoding SMPTE (Society of Motion
Picture and Television Engineers) time code data and for recording on video tapes
21132. A. Biphase-M
21133.
B. B8Z
21134.
C. Manchester
21135.
D. UPNRZ
21136.
79. Pulse-width modulation may be generated
21137. A. by differentiating pulse-position modulation
21138.
B. with a monostable multivibrator
21139.
C. by integrating the signal
21140.
D. with a free-running multivibrator
21141.
80. The ISDN channel D designates _____ which contains control information.
21142. A. Data
21143.
B. Flow
21144.
C. Control
21145.
D. Bearer
21146.
81. A transmission of binary data which involves the transmission of two non-zero
voltage level
21147. A. Unipolar
21148.
B. Polar
21149.
C. Bipolar
21150.
D. Nonreturn to Zero
21151.
82. Switching systems
21152. A. improve the efficiency of data transfer
21153.
B. are not used in data systems
21154.
C. require additional lines
21155.
D. are limited to small data networks
21156.
83. It involves converting standard logic levels to a form more suitable to
telephone transmission lines
21157. A. Transmission line encoding
21158.
B. Physical line encoding
21159.
C. Digital line encoding
21160.
D. Multiplexing
21161.
84. The primary advantage of digital transmission
21162. A. economical
21163.
B. reliability

21164.
C. noise immunity
21165.
D. efficiency
21166.
85. Part of the PCM system that prevents aliasing or foldover distortion
21167. A. Bandpass filter
21168.
B. Anti-foldover distortion
21169.
C. Anti-aliasing
21170.
D. Any of these
21171.
86. It is defined as the process of transforming messages or signals in accordance
with a definite set of rules.
21172. A. Quantizing
21173.
B. Sampling
21174.
C. Coding
21175.
D. Decoding
21176.
87. The PCM code for each channel occupies a fixed time slot called
21177. A. Frame time
21178.
B. Baud
21179.
C. Transmission line
21180.
D. Epoch
21181.
88. The building block of a parity or BCC generator is _____.
21182. A. Shift register
21183.
B. XOR
21184.
C. 2-to-4 level converter
21185.
D. UART
21186.
89. An IC that contains A/D and D/A converters, companders, and parallel-toserial converters is called a
21187. A. Codec
21188.
B. Data converter
21189.
C. Multiplexer
21190.
D. Modem
21191.
90. Data Communications refers to the transmission of
21192. A. voice
21193.
B. video
21194.
C. computer data
21195.
D. all of above
21196.
91. The number of amplitude, frequency, or phase changes that take place per
second is known as the
21197. A. data rate in bits per second
21198.
B. frequency of operation
21199.
C. speed limit
21200.
D. baud rate
21201.
92. The basic modulator and demodulator circuits in PSK are
21202. A. PLLs
21203.
B. Balanced modulators
21204.
C. Shift registers
21205.
D. Linear summers
21206.
93. What is the result if the input of ADC is changing while performing

vonersion?
21207. A. Aperture error
21208.
B. Overload distortion
21209.
C. Aliasing
21210.
D. Aperture distortion
21211.
94. Information capacity is convenient to express as
21212. A. baud
21213.
B. bits
21214.
C. dot length
21215.
D. bits per second or bps
21216.
95. Which medium is the least susceptible to noise?
21217. A. twin lead
21218.
B. fiber-optic cable
21219.
C. twisted pair
21220.
D. coax
21221.
96. The RS-232 interface
21222. A. interconnects data sets and transmission circuits
21223.
B. uses several different connectors
21224.
C. permits custom wiring of signal lines to the connector pins as desired
21225.
D. all of the above
21226.
97. The ISDN channel B designates _____
21227. A. Bearer
21228.
B. Data
21229.
C. Control
21230.
D. Flow
21231.
98. Data transmission of the character at a time with start and stop bits is known
as what type of transmission?
21232. A. asynchronous
21233.
B. serial
21234.
C. synchronous
21235.
D. parallel
21236.
99. Sampling technique that when the tops of the sample pulses retain their
natural shape during the sample interval
21237. A. unnatural sampling
21238.
B. flat top sampling
21239.
C. natural sampling
21240.
D. free sampling
21241.
100. A modem converts
21242. A. Analog signals to digital
21243.
B. Digital signals to analog
21244.
C. Digital signals to analog and vice-versa
21245.
D. none of these
21246.
101. It is a large scale integration chip designed for use in telecommunication
industry for private branch exchanges, central office switches, digital handsets and digital
echo suppressors.
21247. A. Vocoder

21248.
B. Modem
21249.
C. Codec
21250.
D. Muldem
21251.
102. What is the type of mastergroup used for low-capacity microwave systems?
21252. A. A600
21253.
B. U600
21254.
C. L600
21255.
D. L400
21256.
103. An FDM hierarchy which is formed by frequency-division multiplexing five
groups containing 12 channels each for a combined bandwidth of 240 kHz
21257. A. Supergroup
21258.
B. Group
21259.
C. Mastergroup
21260.
D. Jumbogroup
21261.
104. The result whenever the sampling rate is less than the twice the highest audio
frequency
21262. A. peak limiting
21263.
B. overload distortion
21264.
C. alias
21265.
D. quantizing noise
21266.
105. The most critical and difficult part of receiving a direct-sequence spread
spectrum is
21267. A. Frequency synthesis
21268.
B. Synchronism
21269.
C. PSN code generation
21270.
D. Carrier recovery
21271.
106. An FDM hierarchy which is formed by frequency-division multiplexing 10
supergroups together for a combined capacity of 600 voice band message channels
21272. A. Supergroup
21273.
B. Group
21274.
C. Mastergroup
21275.
D. Jumbogroup
21276.
107. It is the transmittal of digital signals between two or more points in a
communications system.
21277. A. digital transmittal
21278.
B. digitals communications
21279.
C. digital radio
21280.
D. data communications
21281.
108. It is logically equivalent to making telephone call through the DDD network
except no direct end-to-end connection is made
21282. A. Normal call
21283.
B. Completed call
21284.
C. Logical call
21285.
D. Virtual call
21286.
109. It is a proposed network designed by major telephone companies in
conjunction with the ITU-T with the intent of providing worldwide telecommunications

support for voice, data, video, and facsimile information within the same network.
21287. A. ISDN
21288.
B. Broadband communications
21289.
C. ATM
21290.
D. Ethernet
21291.
110. Full duplex operation
21292. A. requires two pairs of cables
21293.
B. can transfer data in both directions at once
21294.
C. requires modem at both ends of the circuit
21295.
D. all of these
21296.
111. The most widely used data communications code is
21297. A. Morse
21298.
B. ASCII
21299.
C. Baudot
21300.
D. EBCDIC
21301.
112. Ten bit errors in two million transmitted. The bit error rate is
−5
21302. A. 2× 10
−5
21303. B. 5 ×10
−6
21304. C. 5 ×10
−6

21305. D. 2× 10

21306.
113. It is a type of FSK where the mark and space frequencies are synchronized
with the input binary rate
21307. A. QFSK
21308.
B. GFSK
21309.
C. CPFSK
21310.
D. GSK
21311.
114. A form of digital modulation similar to PSK except the digital information is
contained in both the amplitude and the phase of the transmitted carrier.
21312. A. ASK
21313.
B. FSK
21314.
C. QAM
21315.
D. PSK
21316.
115. For a 16-PSK and a transmission system with a 10 kHz bandwidth,
determine the maximum bit rate
21317. A. 40,000 bps
21318.
B. 80,000 bps
21319.
C. 20,000 bps
21320.
D. 16,000 bps
21321.
116. It is an empirical record of a system’s actual bit error performance.
21322. A. probability of error
21323.
B. error detection
21324.
C. error control
21325.
D. bit error rate

21326.
117. It is a function of the carrier-to-noise power ration and the number of
possible encoding conditions used
21327. A. probability of error
21328.
B. error detection
21329.
C. error control
21330.
D. bit error rate
21331.
118. It is used to compare two or more digital modulation systems that use
different transmission rates, modulation scheme or encoding techniques
21332. A. Energy per bit-to-noise power density ratio
21333.
B. Noise power density
21334.
C. power density ratio
21335.
D. carrier-to-noise ratio
21336.
119. Indicate which of the following is not a binary code.
21337. A. Morse
21338.
B. Baudot
21339.
C. CCITT-2
21340.
D. ARQ
21341.
120. To permit the selection of 1 out of 16 equiprobable events, the number of bits
required is
21342. A. 2
21343.
B. log 16 base 10
21344.
C. 8
21345.
D. 4
21346.
121. The type of modulation most often used with direct-sequence spread
spectrum is
21347. A. QAM
21348.
B. SSB
21349.
C. FSK
21350.
D. PSK
21351.
122. Indicate the false statement. In order to combat noise,
21352. A. the channel bandwidth may be increased
21353.
B. redundancy may be used
21354.
C. the transmitted power may be increased
21355.
D. the signaling rate may be reduced
21356.
123. Which of the following is not commonly used method of error detection?
21357. A. Parity
21358.
B. BCC
21359.
C. CRC
21360.
D. redundancy
21361.
124. Quantizing noise occurs in
21362. A. time-division multiplex
21363.
B. frequency-division multiplex
21364.
C. pulse-code modulation
21365.
D. pulse width modulation
21366.
125. In order to reduce quantizing noise, one must
21367. A. increase the number of standard amplitudes

21368.
B. send pulses whose sides are more nearly vertical
21369.
C. use an RF amplifier in the receiver
21370.
D. increase the number of samples per second
21371.
126. Companding is used
21372. A. to overcome quantizing noise in PCM
21373.
B. in PCM transmitters, to allow amplitude limiting in the receivers
21374.
C. to protect small signals in PCM from quantizing distortion
21375.
D. in PCM receivers, to overcome impulse noise
21376.
127. Transmitting data as serial binary words is called _____.
21377. A. digital communications
21378.
B. quantizing
21379.
C. PAM
21380.
D. PCM
21381.
128. Emphasizing low-level signals and compressing higher-level signals is called
21382. A. quantizing
21383.
B. companding
21384.
C. pre-emphasis
21385.
D. sampling
21386.
129. Which circuit is common to both frequency-hopping and direct-sequence
spread spectrum transmitters?
21387. A. Correlator
21388.
B. Frequency synthesizer
21389.
C. PSN code generator
21390.
D. Sweep generator
21391.
130. One of the most important aspect of any communication system because it’s
costly and limited
21392. A. bandwidth
21393.
B. equipments
21394.
C. time
21395.
D. personnel
21396.
131. It consist essentially of sampling analog information signals and then
converting those samples into discreet pulses of transporting the pulses from a source to
destination over a physical transmission medium
21397. A. pulse modulation
21398.
B. amplitude modulation
21399.
C. frequency modulation
21400.
D. digital modulation
21401.
132. He is credited with inventing PCM in 1937
21402. A. N.S. Kapany
21403.
B. A.H. Reeves
21404.
C. E.H. Alpine
21405.
D. A.C.S. Van Heel
21406.
133. Data communications uses
21407. A. analog methods
21408.
B. digital methods
21409.
C. either of these

21410.
D. neither of these
21411.
134. An integrated circuit that performs the PCM encoding and decoding
functions
21412. A. Codec
21413.
B. Modem
21414.
C. Muldem
21415.
D. Digital-to-analog converter
21416.
135. A synchronous transmission usually begins with which character?
21417. A. SYN
21418.
B. STX
21419.
C. SOH
21420.
D. ETB
21421.
136. A theorem that establishes the minimum sampling rate that can be used for a
given PCM systems
21422. A. Nyquist sampling theorem
21423.
B. Nyquist minimum bandwidth
21424.
C. Nyquist minimum bandwidth
21425.
D. Any of these
21426.
137. Sixteen different levels (symbols) are used to encode binary data. The
channel bandwidth is 36 MHz. the maximum channel capacity is
21427. A. 187 Mbps
21428.
B. 72 Mbps
21429.
C. 288 Mbps
21430.
D. 2.176 Gbps
21431.
138. Assigning PCM codes to absolute magnitudes
21432. A. Coding
21433.
B. Quantizing
21434.
C. Sampling
21435.
D. Any of these
21436.
139. A popular PC protocol is
21437. A. Parity
21438.
B. Xmodem
21439.
C. CRC
21440.
D. LRC
21441.
140. It is the ratio of the largest possible magnitude to the smallest possible
magnitude that can be decoded by the digital-to-analog converter in the receiver
21442. A. Coding efficiency
21443.
B. Companding
21444.
C. Pre-emphasis
21445.
D. Dynamic range
21446.
141. Devices used for digitizing speech signals only
21447. A. codec
21448.
B. muldem
21449.
C. vocoders
21450.
D. modem
21451.
142. What is the minimum bandwidth required to transmit 56 kbps binary signal

with no noise?
21452. A. 14 kHz
21453.
B. 56 kHz
21454.
C. 28 kHz
21455.
D. 112 kHz
21456.
143. Type of PCM that uses single-bit PCM code to achieve digital transmission
of analog signals
21457. A. Adaptive delta modulation
21458.
B. Pulse code modulation
21459.
C. Differential modulation
21460.
D. Delta modulation
21461.
144. It is a delta modulation system where the step size of the Digital-to-Analog
converter is automatically varied, depending on the analog input signal
21462. A. Adaptive delta modulation
21463.
B. Pulse code modulation
21464.
C. Differential modulation
21465.
D. Delta modulation
21466.
145. A QAM modulator does not use _____
21467. A. XNOR
21468.
B. Bit splitter
21469.
C. Balanced modulator
21470.
D. 2-to-4 level converter
21471.
146. It is a form of phase-division multiplexing where two data channels
modulate the same carrier frequency that is shifted 90 degrees in phase.
21472. A. PSK
21473.
B. FSK
21474.
C. QAM
21475.
D. ASK
21476.
147. One eight0bit PCM code is called ______
21477. A. FDM frame
21478.
B. TDM time slot
21479.
C. TDM frame
21480.
D. FDM time slot
21481.
148. It is a communication system that uses digital pulse rather than analog
signals to encode information
21482. A. Digital carrier system
21483.
B. Digital baseband system
21484.
C. Digital service system
21485.
D. Digital broadband system
21486.
149. A special device that upgrades signals from one level to a higher level of the
hierarchy in multiplexing
21487. A. Muldem
21488.
B. Vocoder
21489.
C. Modem
21490.
D. Codec
21491.
150. A transmission of binary data which involves the transmission of only a

single non-zero voltage level.
21492. A. Unipolar
21493.
B. Polar
21494.
C. Bipolar
21495.
D. Nonreturn to zero
21496.
151. If the active time of the binary pulse is less than 100% of the bit time
21497. A. Non return to zero
21498.
B. Bipolar
21499.
C. Unipolar
21500.
D. Return to zero
21501.
152. It is a popular type of line encoding that produces a strong timing component
for clock recovery and does not cause wandering
21502. A. Digital biphase
21503.
B. diphase
21504.
C. Manchester code
21505.
D. Any of these
21506.
153. Statistical TDMs are also called
21507. A. Intelligent TDMs
21508.
B. Asynchronous TDM
21509.
C. Stat mux
21510.
D. Any of these
21511.
154. A chip that combines the codec and filter functions in the same LSI chip
21512. A. Monolithic
21513.
B. Combo chip
21514.
C. Film IC
21515.
D. Hybrid chip
21516.
155. It is the basic building block of FDM hierarchy
21517. A. Character channel
21518.
B. Broadband channel
21519.
C. Message channel
21520.
D. Information capacity
21521.
156. It is the next higher level in the FDM hierarchy above the basic message
channel and consequently is the first multiplexing step for combining message channels
21522. A. Supergroup
21523.
B. Group
21524.
C. Mastergroup
21525.
D. Jumbogroup
21526.
157. It is the modulating signal in a communications system
21527. A. Broadband
21528.
B. Baseband
21529.
C. Carrier
21530.
D. Any of these
21531.
158. What type of mastergroup that can be further multiplexed and used for
higher-capacity microwave radio systems?
21532. A. A600
21533.
B. U600

21534.
C. L600
21535.
D. L400
21536.
159. It is essentially the same with FDM, where several signals are transmitted
using different carriers, occupying non-overlapping bands of frequency and wavelengths.
21537. A. Time division multiplexing
21538.
B. Wave division multiplexing
21539.
C. Space division multiplexing
21540.
D. Frequency division multiplexing
21541.
160. In order to separate channels in the TDM receiver, it is necessary to use
21542. A. AND gates
21543.
B. bandpass filters
21544.
C. differentiation
21545.
D. integration
21546.
161. To separate channels in an FDM receiver, it is necessary to use
21547. A. AND gates
21548.
B. bandpass filters
21549.
C. differentiation
21550.
D. integration
21551.
162. In FDM, multiple signals
21552. A. transmit at different times
21553.
B. share a common bandwidth
21554.
C. use multiple channels
21555.
D. modulate one another
21556.
163. Frequency modulation in FDM usually accomplished with a
21557. A. reactance modulator
21558.
B. varactor
21559.
C. VCO
21560.
D. PLL
21561.
164. Which of the following is not a common LAN medium?
21562. A. twin lead
21563.
B. twisted pair
21564.
C. fiber-optic cable
21565.
D. coax
21566.
165. A mainframe computer connected to multiple terminals and PCs usually uses
which configuration?
21567. A. bus
21568.
B. ring
21569.
C. star
21570.
D. tree
21571.
166. How many voice channels are there in supermaster group?
21572. A. 300
21573.
B. 900
21574.
C. 3600
21575.
D. 10800
21576.
167. In a PAM/TDM system, keeping the multiplexer and DEMUX channels step
with one another is done by a

21577. A. clock recovery circuit
21578.
B. sync pulse
21579.
C. sampling
21580.
D. sequencer
21581.
168. It is the process of volume compression before transmission and expansion
after detection.
21582. A. pre-emphasis
21583.
B. de-emphasis
21584.
C. coding
21585.
D. companding
21586.
169. Which of the following is correct?
21587. A. The bit rate may be greater than the baud rate
21588.
B. The baud rate may be greater than the bit rate
21589.
C. The bit and baud rate are always the same
21590.
D. The bit and baud rates are not related
21591.
170. Function of data link protocol that coordinates the rate at which data are
transported over a link and generally provides an acknowledgement mechanism that
ensures that data are received in the destination.
21592. A. Flow control
21593.
B. Line discipline
21594.
C. Polling
21595.
D. Selection
21596.
171. A classification of protocol, which is a discipline for a serial-by-bit
information transfer over data communications channel.
21597. A. Message oriented
21598.
B. Bit-oriented protocol
21599.
C. Clock oriented protocol
21600.
D. Asynchronous protocol
21601.
172. A LAN device that interconnects two or more device running identical
internetwork protocols.
21602. A. Bridges
21603.
B. Gateways
21604.
C. Switches
21605.
D. Routers
21606.
173. The magnitude of a quantum in quantization of PCM codes.
21607. A. Maximum decodable voltage
21608.
B. Dynamic range
21609.
C. Resolution
21610.
D. Coding level
21611.
174. It comprises of either a single L600 mastergroup or up to three U600
mastergroups
21612. A. Message channel
21613.
B. Radio channel
21614.
C. Baseband channel
21615.
D. Wide channel
21616.
175. It is a multiplexing system similar to conventional time-division

multiplexing except that it was developed to be used with optical fibers
21617. A. SONET
21618.
B. Frame relay
21619.
C. ATM
21620.
D. X.25
21621.
176. Higher order TDM levels are obtained by
21622. A. dividing pulse widths
21623.
B. using the a-law
21624.
C. using u-law
21625.
D. forming supermastergroups
21626.
177. Results when the sample exceeds the highest quantization interval
21627. A. Overload distortion
21628.
B. Quantization error
21629.
C. Quantization noise
21630.
D. Granular noise
21631.
178. The event which marked the start of the modern computer age was
21632. A. design of the ENIAC computer
21633.
B. development of Hollerith code
21634.
C. development of the transistor
21635.
D. development of disk drives for data storage
21636.
179. A forward error correcting code corrects errors by
21637. A. requiring partial transmission of the entire signal
21638.
B. requiring retransmission of the entire signal
21639.
C. requiring no part of the signal to be transmitted
21640.
D. using parity to correct the errors in all cases
21641.
180. The carrier used with a BPSK demodulator is
21642. A. Generated by an oscillator
21643.
B. The BPSK signal itself
21644.
C. Twice the frequency of the transmitted carrier
21645.
D. Recovered from the BPSK signal
21646.
181. Digital signals
21647. A. do not provide a continuous set of values
21648.
B. represent values as discrete steps
21649.
C. can utilize decimal or binary systems
21650.
D. all of these
21651.
182. Each signal in an FDM signal
21652. A. modulates the main carrier
21653.
B. modulates the final carrier
21654.
C. is mixed with all the others before modulation
21655.
D. serves as a subcarrier
21656.
183. In digital modulation, if the information signal is digital and the amplitude of
the carrier is varied proportional to the information signal.
21657. A. Quartenary Shift Keying (QAM)
21658.
B. Phase Shift Keying (PSK)
21659.
C. Frequency Shift Keying (FSK)
21660.
D. Amplitude Shift Keying (ASK)

21661.
184. Slow speed modems
21662. A. FSK
21663.
B. BPSK
21664.
C. QPSK
21665.
D. QAM
21666.
185. The data rate for IEEE 802.11b is _____.
21667. A. 10 Mbps
21668.
B. 1.544 Mbps
21669.
C. 2.048 Mbps
21670.
D. 11 Mbps
21671.
186. Type of analog companding used in the United States and Japan
21672. A. log-PCM companding
21673.
B. A-law companding
21674.
C. u-law companding
21675.
D. any of these
21676.
187. A rule of procedure that defines how data is to be transmitted is called
21677. A. handshake
21678.
B. error-detection
21679.
C. data specifications
21680.
D. protocol
21681.
188. A longitudinal redundancy check produces
21682. A. block check character
21683.
B. parity bit
21684.
C. CRC
21685.
D. error correction
21686.
189. Multiplexing is the process of
21687. A. Several signal sources transmitting simultaneously to a receiver on common
frequency
21688.
B. Sending the same signal over multiple channels to multiple destinations
21689.
C. Transmitting multiple signals over multiple channels
21690.
D. Sending multiple signals simultaneously over a single channel
21691.
190. What is the relationship of bit rate and baud in QPSK and 8-PSK?
21692. A. bit rate is greater than baud
21693.
B. bit rate is always less than the baud
21694.
C. bit rate is never greater than the baud
21695.
D. bit rate is slightly less than the baud
21696.
191. A common method of achieving carrier recovery for BPSK
21697. A. Trellis code
21698.
B. Bandwidth efficiency
21699.
C. Squaring loop
21700.
D. Carrier recovery
21701.
192. What is the relationship of bit rate and baud in FSK and PSK?
21702. A. greater than
21703.
B. slightly greater than
21704.
C. less than
21705.
D. equal

21706.
193. The modulation used in FDM telephone system is
21707. A. AM
21708.
B. FM
21709.
C. SSB
21710.
D. PSK
21711.
194. In digital modulation, a diagram which is similar to phasor diagram except
that the entire phasor is not drawn and only the peaks of the phasor are shown
21712. A. constellation diagram
21713.
B. Venn diagram
21714.
C. phasor diagram
21715.
D. schematic diagram
21716.
195. Digital signals may be transmitted over the telephone network if
21717. A. their speed is low enough
21718.
B. they are converted to analog first
21719.
C. they are ac instead of dc
21720.
D. they are digital only
21721.
196. Most FDM telemetry system use
21722. A. AM
21723.
B. FM
21724.
C. SSB
21725.
D. PSK
21726.
197. In TDM, multiple signals
21727. A. share a common bandwidth
21728.
B. modulate subcarriers
21729.
C. are sampled at high speeds
21730.
D. take turns transmitting
21731.
198. It is highly theoretical study of efficient use of bandwidth to propagate
information through electronic communications system
21732. A. information capacity
21733.
B. data communications
21734.
C. information theory
21735.
D. information technology
21736.
199. Another name for parity is
21737. A. Vertical redundancy check
21738.
B. Block check character
21739.
C. Longitudinal redundancy check
21740.
D. Cyclic redundancy check
21741.
200. It is the process of gathering data on some particular phenomenon without
the presesnce of human monitors
21742. A. Telemetry
21743.
B. Telecommand
21744.
C. Telecommunications
21745.
D. Remote control
21746.
201. A convenient technique for determining the effects of the degradations
introduced into the pulses as they travel to the regenerator.
21747. A. Standing wave ratio

21748.
B. Eye patterns
21749.
C. Reflection coefficient
21750.
D. Any of these
21751.
202. Spread spectrum stations sharing a band are identified by and distinguished
from one another
21752. A. PSN code
21753.
B. Frequency of operation
21754.
C. Clock rate
21755.
D. Modulation type
21756.
203. The ASCII code has
21757. A. 4 bits
21758.
B. 5 bits
21759.
C. 7 bits
21760.
D. 8 bits
21761.
204. The first file transfer protocol designed to facilitate transferring data between
two personal computers over the public switched telephone network
21762. A. X modem protocol
21763.
B. Y modem protocol
21764.
C. Z modem protocol
21765.
D. BLAST
21766.
205. For a single-channel PCM system with a sample rate of 6000 samples per
second and a seven-bit compressed PCM code, what is the line speed?
21767. A. 21,000 bps
21768.
B. 42,000 bps
21769.
C. 14,000 bps
21770.
D. 12,000 bps
21771.
206. It is often used to compare the performance of one digital modulation
technique to another
21772. A. Bandwidth efficiency
21773.
B. Spectral efficiency
21774.
C. Information density
21775.
D. All of these
21776.
207. It is the process of extracting a phase-coherent reference carrier from a
receiver signal
21777. A. Phase referencing
21778.
B. Trellis code
21779.
C. Squaring loop
21780.
D. any of these
21781.
208. It is the measure of how much information can be propagated through a
communication system and is a function of a bandwidth of the transmission line
21782. A. information theory
21783.
B. information capacity
21784.
C. information technology
21785.
D. digital communications
21786.
209. In delta modulation, the modulator is sometimes called _____.
21787. A. continuous ADC

21788.
B. tracking ADC
21789.
C. variable slope ADC
21790.
D. slope ADC
21791.
210. The code which provides for parity checks is
21792. A. Baudot
21793.
B. ASCII
21794.
C. CCITT-2
21795.
D. EBCDIC
21796.
211. Form of multiplexing that constitutes propagating signals from different
cables that sre contained within the same trench
21797. A. Wavelength division multiplexing
21798.
B. Wave division multiplexing
21799.
C. Space division multiplexing
21800.
D. Frequency division multiplexing
21801.
212. For an 8-PSK system, operating with an information bit rate of 24 kbps,
determine the bandwidth efficiency
21802. A. 8 bits/cycle
21803.
B. 2 bits/cycle
21804.
C. 3 bits/cycle
21805.
D. 4 bits/cycle
21806.
213. Element of a PCM system that periodically samples the analog input signal
and converts those samples to a multilevel PAM signal
21807. A. Bandpass filter
21808.
B. Sample-and-hold circuit
21809.
C. Analog-to-digital converter
21810.
D. Digital-to-analog converter
21811.
214. It is the ratio of the average carrier power to the thermal noise power
21812. A. Signal-to-noise ratio
21813.
B. Noise figure
21814.
C. Noise factor
21815.
D. Carrier-to-noise ratio
21816.
215. A form of switching which is hold and forward
21817. A. Packet switching
21818.
B. Message switching
21819.
C. Circuit switching
21820.
D. Digital switching
21821.
216. It can be used to categorize the type of transmission
21822. A. Duty cycle
21823.
B. Companding
21824.
C. Coding efficiency
21825.
D. Dynamic range
21826.
217. Type of multiplexing where multiple sources that originally occupied the
same frequency spectrum are each converted to a different frequency band and
transmitted simultaneously over a single transmission medium.
21827. A. FDM
21828.
B. ATM

21829.
C. TDM
21830.
D. Spread spectrum
21831.
218. It is a solicitation sent from the primary to a secondary to determine if the
secondary has data to transmit
21832. A. Selection
21833.
B. Polling
21834.
C. Error control
21835.
D. Master control
21836.
219. Function of data link control that specifies the means of detecting and
correcting transmission errors
21837. A. Error control
21838.
B. Selection
21839.
C. Protocol
21840.
D. Synchronization
21841.
220. The Hartley law states that
21842. A. the maximum rate of information transmission depends on the channel
bandwidth
21843.
B. the maximum rate of information depends on the depth of modulation
21844.
C. redundancy is essential
21845.
D. only binary codes may be used
21846.
221. It represents the number of independent symbols that can be carried through
a system in a given unit of time.
21847. A. information theory
21848.
B. information capacity
21849.
C. information technology
21850.
D. digital communications
21851.
222. The Shannon-Hartley law
21852. A. refers to distortion
21853.
B. defines the bandwidth
21854.
C. describes signaling rates
21855.
D. refers to noise
21856.
223. The most basic digital symbol used to represent information
21857. A. bit
21858.
B. baud
21859.
C. bits per second
21860.
D. any of these
21861.
224. Function of data link protocol that coordinates hop-to-hop data delivery
where a hop maybe a computer, a network controller or a network-connecting device
such as router.
21862. A. Flow control
21863.
B. Error control
21864.
C. Line discipline
21865.
D. Selection
21866.
225. Quadrature amplitude modulation is
21867. A. Amplitude modulation only
21868.
B. QPSK only

21869.
C. AM plus QPSK
21870.
D. AM plus FSK
21871.
226. The most common modulation system used for telegraphy is
21872. A. frequency-shift keying
21873.
B. two-tone modulation
21874.
C. pulse-code modulation
21875.
D. single-tone modulation
21876.
227. It is used to encode the minimum amount of speech information necessary to
reproduce a perceptible message with a fewer bits that those needed by a conventional
encoder/decoder
21877. A. codec
21878.
B. muldem
21879.
C. vocoders
21880.
D. modem
21881.
228. It is the transmission of information in any form from one source to one or
more destination
21882. A. Modulation
21883.
B. Multiplexing
21884.
C. Encoding
21885.
D. Decoding
21886.
229. A form of switching which is stored and forward
21887. A. Packet switching
21888.
B. Message switching
21889.
C. Circuit switching
21890.
D. Digital switching
21891.
230. In digital modulation, it is similar to standard amplitude modulation except
there is only two amplitudes possible
21892. A. frequency shift keying
21893.
B. quartenary amplitude modulation
21894.
C. amplitude shift keying
21895.
D. phase shift keying
21896.
231. The technique of using modulation and FDM to transmit multiple data
channels of a common medium is known as
21897. A. baseband
21898.
B. broadband
21899.
C. ring
21900.
D. bus
21901.
232. Which of the following is not a benefit of companding
21902. A. minimizes noise
21903.
B. minimizes number of bits
21904.
C. minimizes quantizing error
21905.
D. minimizes signal bandwidth
21906.
233. Transmissions from multiple sources occur in the same facility but not at the
same time
21907. A. Time Division Multiplexing
21908.
B. Frequency Division Multiplexing

21909.
C. Wave Division Multiplexing
21910.
D. Space Division Multiplexing
21911.
234. A 9600-baud rate signal can pass over the voice grade telephone line if which
kind of modulation is used?
21912. A. BPSK
21913.
B. QPSK
21914.
C. DPSK
21915.
D. QAM
21916.
235. Indicate which of the following pulse modulation systems is analog
21917. A. PCM
21918.
B. PWM
21919.
C. Differential PCM
21920.
D. Delta
21921.
236. The modulation system inherently most noise-resistant is
21922. A. SSB, suppressed carrier
21923.
B. frequency modulation
21924.
C. pulse-position modulation
21925.
D. pulse-code modulation
21926.
237. It is simply the number of bits transmitted during one second and expressed
in bits per second
21927. A. baud
21928.
B. bits
21929.
C. bit rate
21930.
D. pulse repetition rate
21931.
238. It is the most prevalent encoding technique used for TDM signals
21932. A. PAM
21933.
B. PLM
21934.
C. PPM
21935.
D. PCM
21936.
239. The characters making up the message in a synchronous transmission are
collectively referred to as the data
21937. A. set
21938.
B. sequence
21939.
C. block
21940.
D. collection
21941.
240. A virtual circuit which is logically equivalent to a two-point dedicated
private-line circuit except slower
21942. A. Switched Virtual Circuit
21943.
B. Permanent Virtual Circuit
21944.
C. Switched Leased Circuit
21945.
D. Permanent Leased Circuit
21946.
241. To a conventional narrowband receiver, a spread spectrum signal appears to
be like
21947. A. Noise
21948.
B. Fading
21949.
C. A jamming signal

21950.
D. An intermittent connection
21951.
242. It is a low-quality video transmission for use between non-dedicated
subscribers
21952. A. Digital phone
21953.
B. Picturephone
21954.
C. Cameraphone
21955.
D. Cellphone with camera
21956.
243. Pulse code modulation is preferred to PAM because of its
21957. A. resistance to quantizing errror
21958.
B. simplicity
21959.
C. lower cost
21960.
D. superior noise immunity
21961.
244. A CRC generator uses which component?
21962. A. balanced modulator
21963.
B. shift register
21964.
C. binary adder
21965.
D. multiplexer
21966.
245. A signaling element is sometimes called
21967. A. information
21968.
B. data
21969.
C. symbol
21970.
D. intelligence
21971.
246. Which of the following words has the correct parity bit? Assume odd parity.
The last bit is the parity bit.
21972. A. 1111111 1
21973.
B. 1100110 1
21974.
C. 0011010 1
21975.
D. 0000000 0
21976.
247. It is a digital interface that provides the physical connection to the digital
carrier network
21977. A. Modem
21978.
B. Codec
21979.
C. Muldem
21980.
D. DSU/CSU
21981.
248. It is the only digitally encoded modulation technique that is commonly used
for digital transmission
21982. A. PAM
21983.
B. PCM
21984.
C. PLM
21985.
D. PPM
21986.
249. The most common circuit used for demodulating binary FSK signals
21987. A. phase locked loop
21988.
B. Foster-Seeley discriminator
21989.
C. varactor
21990.
D. phase shift method
21991.
250. A digital modulation technique also known as “on-off” keying

21992. A. PSK
21993.
B. FSK
21994.
C. QUAM
21995.
D. OOK
21996.
21997.
21998.
21999.
22000.
22001.
22002.
22003.
22004.

22005. MULTIPLE CHOICE QUESTIONS IN

22006. MISCELLANEOUS
TOPICS
22007.

Electronics Systems and Technologies
22008. By
22009.

Melvin C. Arceo
22010.
22011.
22012.
22013.
22014.
22015.
22016.
22017.
22018.
22019.

22020. ENCODED BY:
22021. GIRAO, Edward Joseph D.
22022.

1. It is the provision of voice communication using Internet Protocol (IP)
technology, instead of traditional circuit switched technology
22023. A. VOIP
22024.
B. Bluetooth
22025.
C. WIFI
22026.
D. WIMAX
22027.
2. Bluetooth enabled electronic devices connect and communicate wirelessly
through short-range, ad hoc networks known as _____.
22028. A. nanonet

22029.
B. scatternet
22030.
C. piconet
22031.
D. netnet
22032.
3. Each device can simultaneously communicate with up to ______ other devices
with a single piconet.
22033. A. 8
22034.
B. 5
22035.
C. 10
22036.
D. 7
22037.
4. The core specification version of Bluetooth that uses Enhanced Data Rate
(EDR)
22038. A. Version 1.0
22039.
B. Version 2.0
22040.
C. Version 1.2
22041.
D. Version 2.1
22042.
5. Bluetooth technology operates in the _____ band.
22043. A. ISM
22044.
B. C band
22045.
C. MSI
22046.
D. Ku band
22047.
6. Bluetooth technology operates in the band
22048. A. 2.4 to 2.485 GHz
22049.
B. 2.42 to 2.44 GHz
22050.
C. 2.48 to 2.52 GHz
22051.
D. 2.3 to 2.45 GHz
22052.
7. The hopping rate of Bluetooth is
22053. A. 1000 hops/sec
22054.
B. 1600 hops/sec
22055.
C. 1500 hops/sec
22056.
D. 2500 hops/sec
22057.
8. Technology used by Bluetooth designed to reduce interference between
wireless technologies sharing the 2.4 GHz spectrum
22058. A. AFH
22059.
B. DSSS
22060.
C. OFDM
22061.
D. FHSS
22062.
9. The signal hops among ______ frequencies at 1 MHz intervals to give a high
degree of interference immunity
22063. A. 80
22064.
B. 78
22065.
C. 81
22066.
D. 79
22067.
10. Class 3 radios used for Bluetooth technology have a range of up to
22068. A. 1 ft
22069.
B. 2 ft
22070.
C. 3 ft

22071.
D. 4 ft
22072.
11. Class 2 radios used for Bluetooth most commonly found in mobile devices
have a range of ______.
22073. A. 10 ft
22074.
B. 20 ft
22075.
C. 15 ft
22076.
D. 30 ft
22077.
12. Class 1 radios used primarily in industrial use cases have a range of
22078. A. 100 meters
22079.
B. 25 meters
22080.
C. 10 meters
22081.
D. 50 meters
22082.
13. Bluetooth technology uses ______ of power.
22083. A. 2.6 mW
22084.
B. 2.5 mW
22085.
C. 2,8 mW
22086.
D. 2.7 mW
22087.
14. What is the data rate used by Bluetooth technology using version 1.2
specification?
22088. A. 1 Mbps
22089.
B. 2 Mbps
22090.
C. 3 Mbps
22091.
D. 4 Mbps
22092.
15. What is the data rate used by Bluetooth technology using version 2.0 + EDR
specification?
22093. A. 1 Mbps
22094.
B. 3 Mbps
22095.
C. 2 Mbps
22096.
D. 4 Mbps
22097.
16. Bluetooth technology has built-in security such as _____ bit encryption
22098. A. 64
22099.
B. 16
22100.
C. 32
22101.
D. 128
22102.
17. The symbol rate for Bluetooth is
22103. A. 1 Mega symbol per sec
22104. B. 3 Mega symbol per sec
22105. C. 2 Mega symbol per sec
22106. D. 4 Mega symbol per sec
22107.
18. In satellite communications, for an angle of inclination 0f 63.4 degrees, the
rotation of the line of apsides is ____ degrees
22108. A. 0
22109.
B. 5
22110.
C. 15
22111.
D. 3
22112.
19. An international agreement initially mandated that all satellites placed in the

Clarke or Geosynchronous orbit must be separated by at least
22113. A. 22,300 mi
22114.
B. 3400 mi
22115.
C. 1833 mi
22116.
D. 5544 mi
22117.
20. The radiation pattern of earth coverage antennas of satellites have a
beamwidth of approximately ______.
22118. A. 15 degrees
22119.
B. 17 degrees
22120.
C. 10 degrees
22121.
D. 11 degrees
22122.
21. ______ is a new nonvoice value added service that allows information to be
sent and received across a mobile telephone network.
22123. A. WiFi
22124.
B. Wimax
22125.
C. GPRS
22126.
D. HSCSD
22127.
22. Theoretical maximum speeds of up to _____ kbps are achievable with GPRS
using all _____ timeslots at the same time.
22128. A. 64, 8
22129.
B. 171.2, 8
22130.
C. 128, 7
22131.
D. 183.5, 7
22132.
23. It is the latest standard of MPEG under development that will support
download and execution of multimedia applications.
22133. A. MPEG-21
22134.
B. MPEG-A
22135.
C. MPEG-7
22136.
D. MPEG-E
22137.
24. A new standard line of MPEG standard called multimedia application format
is _____.
22138. A. MPEG-A
22139.
B. MPEG-C
22140.
C. MPEG-B
22141.
D. MPEG-D
22142.
25. MPEG standard on which such products as Digital Television set top boxes
and DVD are based
22143. A. MPEG-1
22144.
B. MPEG-4
22145.
C. MPEG-2
22146.
D. MPEG-7
22147.
26. MPEG standard on which such products as Video CD and MP3 are based
22148. A. MPEG-1
22149.
B. MPEG-7
22150.
C. MPEG-21
22151.
D. MPEG-3

22152.
27. MPEG standard for multimedia for the fixed and mobile web
22153. A. MPEG-1
22154.
B. MPEG-4
22155.
C. MPEG-2
22156.
D. MPEG-7
22157.
28. MPEG standard for description and search of audio and visual content.
22158. A. MPEG-1
22159.
B. MPEG-7
22160.
C. MPEG-21
22161.
D. MPEG-3
22162.
29. The MPEG standard for the Multimedia Framework
22163. A. M3W
22164.
B. MPEG-4
22165.
C. MPEG-7
22166.
D. MPEG-21
22167.
30. Coding of moving pictures and associated audio for digital storage media at
up to about 1.5 Mbps.
22168. A. MPEG-3
22169.
B. MPEG-2
22170.
C. MPEG-4
22171.
D. MPEG-1
22172.
31. Used in MPEG to remove spatial correlation.
22173. A. Discrete Shine Transform
22174.
B. Discreet Cosine Transform
22175.
C. Discreet Secant Transform
22176.
D. Discreet Cosecant Transform
22177.
32. MPEG-4 builds on the proven success on one of the following fields
22178. A. Digital television
22179.
B. Interactive multimedia
22180.
C. Interactive graphics applications
22181.
D. Any of these
22182.
33. The maximum effective power allowed for RFID is _____.
22183. A. 0.5 watt
22184.
B. 3 watts
22185.
C. 1 watt
22186.
D. 0.25 watt
22187.
34. The use and operation of RFIDs shall be allowed in the following frequency
bands except:
22188. A. 13.533-13.567 MHz
22189.
B. 2446-2454 MHz
22190.
C. 918-920 MHz
22191.
D. 254-365 MHz
22192.
35. _____ are radio systems based on local area networking solutions that require
higher data rates and consequently greater bandwidth for new multimedia applications
spectrum requirements
22193. A. WIFI

22194.
B. HiperLAN
22195.
C. WIMAX
22196.
D. VOIP
22197.
36. _____ refers to the determination of the position, velocity and/or other
characteristics of an object, or the obtaining of information relating to these parameters,
by means of the propagation properties of radio waves.
22198. A. position determination
22199.
B. radio determination
22200.
C. velocity determination
22201.
D. range determination
22202.
37. Radio microphones has power of _____ mW or less.
22203. A. 20
22204.
B. 40
22205.
C. 30
22206.
D. 50
22207.
38. _____ referred to as wireless microphones or cordless microphones, are small,
low power, unidirectional transmitters designed to be worn on the body, or hand held, for
the transmission of sound over short distances for personal use.
22208. A. directional microphone
22209.
B. parabolic microphone
22210.
C. radio microphone
22211.
D. spy microphone
22212.
39. _____ are intended to carry data in suitable transporters, generally known as
tags, and to retrieve data, by hand- or manine-readable means, at a suitable time and place
to satisfy particular application needs.
22213. A. RFID
22214.
B. HiperLan
22215.
C. transponder tags
22216.
D. bluetooth
22217.
40. _____ also referred to as dedicated short-range communications for transport
information and control systems are systems providing data communication between two
or more road vehicles and between road vehicles and the road infrastructure for various
information-based travel and transport applications, including automatic toll-collection,
route and parking guidance, collision avoidance and similar applications.
22218. A. RTTY
22219.
B. TICS
22220.
C. RTTT
22221.
D. RSSD
22222.
41. _____ for use with implanted medical devices, like pacemakers, implantable
defibrillators, nerve stimulators, and other types of implanted devices.
22223. A. MICS
22224.
B. TICS
22225.
C. AIDS
22226.
D. PACER
22227.
42. What is the frequency band for biomedical devices?
22228. A. 40.66-40.70 MHz

22229.
B. 13.90-14.40 MHz
22230.
C. 50.44-51.09 MHz
22231.
D. 32.10-33.89 MHz
22232.
43. The electric field intensity of biomedical devices?
22233. A. 1000 µV/m at 3m
22234.
B. 10 µV/m at 3m
22235.
C. 100 µV/m at 3m
22236.
D. 1 µV/m at 3m
22237.
44. _____ refers to the use of radio communication devices for the transmission of
signals to initiate, modify or terminate functions of equipment at a distance.
22238. A. telemetry
22239.
B. wireless application
22240.
C. telecommand
22241.
D. radio beacon
22242.
45. The data rate used by IEEE 802.11b
22243. A. 11 Mbps
22244.
B. 55 Mbps
22245.
C. 54 Mbps
22246.
D. 12 Mbps
22247.
46. The operating frequency of IEEE 802.11b
22248. A. 2.4 GHz
22249.
B. 5.5 GHz
22250.
C. 5 GHz
22251.
D. 2.5 GHz
22252.
47. The operating frequency of IEEE 802.11a
22253. A. 2.5 GHz
22254.
B. 5 GHz
22255.
C. 5.5 GHz
22256.
D. 2.1 GHz
22257.
48. The data rate of IEEE 802.11a
22258. A. 55 Mbps
22259. B. 53 Mbps
22260. C. 54 Mbps
22261.
D. 50 Mbps
22262.
49. _____ is a standards-based wireless technology that provides high-throughput
broadband connections over long distances.
22263. A. Wimax
22264.
B. Wibro
22265.
C. Wifi
22266.
D. Winar
22267.
50. _____ is a wireless broadband technology being developed by the Korean
telecoms industry.
22268. A. Wimax
22269.
B. Wibro
22270.
C. Wifi
22271.
D. Winar

22272.
51. What is the operating frequency of Wibro?
22273. A. 2.1 GHz
22274.
B. 2.3 GHz
22275.
C. 2.2 GHz
22276.
D. 2.4 GHz
22277.
52. What is the base station data throughout for Wibro?
22278. A. 30 to 50 Mbps
22279.
B. 40 to 60 Mbps
22280.
C. 50 to 70 Mbps
22281.
D. 60 to 80 Mbps
22282.
53. The maximum radius for Wibro is ____.
22283. A. 2 km
22284.
B. 3 km
22285.
C. 4 km
22286.
D. 5 km
22287.
54. _____ is a published specification set of high level communication protocols
designed to use small, low-power digital radios based on the IEEE 802.15.4 standard for
wireless personal area networks.
22288. A. bluetooth
22289.
B. wpan
22290.
C. zigbee
22291.
D. wlan
22292.
55. In a Zigbee network, a single device that controls the network is called _____.
22293. A. master
22294.
B. server
22295.
C. coordinator
22296.
D. pointer
22297.
56. Devices being controlled in a zigbee network are known as _____.
22298. A. end devices
22299.
B. clients
22300.
C. slaves
22301.
D. beggars
22302.
57. The modulation scheme used by IEEE 802.11b
22303. A. OFDM
22304.
B. CCK
22305.
C. QPSK
22306.
D. FDM
22307.
58. The modulation scheme used by IEEE 802.11a
22308. A. OFDM
22309.
B. CCK
22310.
C. QPSK
22311.
D. FDM
22312.
59. The World Wide Web or WWW was invented in the year _____.
22313. A. 1991
22314.
B. 1990
22315.
C. 1989

22316.
D. 1995
22317.
60. He invented the World Wide Web or WWW
22318. A. Karel Capek
22319.
B. Tim Berners-Lee
22320.
C. Jon Von Neumann
22321.
D. Bill Gates
22322.
61. The number of satellites used by GLONASS
22323. A. 30
22324.
B. 26
22325.
C. 24
22326.
D. 31
22327.
62. A 3G technology that delivers broadband-like data speeds to mobile devices.
22328. A. EDGE
22329.
B. HSCSD
22330.
C. VOIP
22331.
D. 3GSM
22332.
63. ADSL has maximum distance of _____.
22333. A. 16,000 feet
22334.
B. 8,000 feet
22335.
C. 18,000 feet
22336.
D. 12,000 feet
22337.
64. ______ is an implementation of ADSL that automatically adjusts the
connection speed to adjust for the quality of the telephone line.
22338. A. ADSL
22339.
B. SDSL
22340.
C. RADSL
22341.
D. HDSL
22342.
65. A type of DSL that was developed to support exceptionally high-bandwidth
applications such as High-Definition Television (HDTV).
22343. A. VDSL
22344.
B. SDSL
22345.
C. ADSL
22346.
D. XDSL
22347.
66. A method for moving data over regular phone lines which is much faster than
a regular phone connection and the wires coming into the subscriber’s premises are the
same copper wires used for regular phone service.
22348. A. VOIP
22349.
B. DSL
22350.
C. Cable Internet
22351.
D. POTS
22352.
67. What is the IEEE designation for Bluetooth?
22353. A. 802.15
22354.
B. 802.14
22355.
C. 802.10
22356.
D. 802.16
22357.
68. The IEEE designation for wireless LAN

22358. A. 802.12
22359.
B. 802.13
22360.
C. 802.5
22361.
D. 802.11
22362.
69. The IEEE designation for broadband wireless network
22363. A. 802.16
22364.
B. 802.15
22365.
C. 802.14
22366.
D. 802.13
22367.
70. The file extension for jpeg
22368. A. .jpg
22369.
B. .jpe
22370.
C. .jfif
22371.
D. any of these
22372.
71. In SMS, the number of characters being sent in the network is _____ when
Latin alphabet is used.
22373. A. 80
22374.
B. 160
22375.
C. 65
22376.
D. 100
22377.
72. In SMS, the number of characters being sent in the network is _____ when
non-Latin alphabet is used.
22378. A. 50
22379.
B. 60
22380.
C. 70
22381.
D. 80
22382.
73. It is an enhancement of data services of all current GSM networks, it allows
you to access nonvoice services at 3 times faster
22383. A. GPRS
22384.
B. HSCSD
22385.
C. VOIP
22386.
D. 3GSM
22387.
74. A language derived from HTML especially for wireless network
characteristics.
22388. A. Delphi
22389.
B. PHP
22390.
C. Pearl
22391.
D. WML
22392.
75. The founding father of the Internet
22393. A. Tim Burners-Lee
22394.
B. Vinton Gray Cerf
22395.
C. Jon Von Neumann
22396.
D. Carel Kapek
22397.
76. What term is used by in asynchronous transfer mode (ATM) system to
describe a byte?
22398. A. harmonic

22399.
B. octet
22400.
C. actave
22401.
D. bit
22402.
77. The relative permittivity of silicon is _____
22403. A. 11.7
22404.
B. 1.17
22405.
C. 1.18
22406.
D. 11.8
22407.
78. One of the following is NOT classified as a Customer Premises Equipment
(CPE) by the NTC.
22408. A. Automatic Teller Machine
22409.
B. Videophone Terminal Equipment
22410.
C. VSAT
22411.
D. ISDN Terminal Equipment
22412.
79. Zigbee network layer supports the following topologies except:
22413. A. tree
22414.
B. bus
22415.
C. star
22416.
D. mesh
22417.
80. An Internet Messaging service can be either _____.
22418. A. user-based or company based
22419.
B. sender-based or receiver based
22420.
C. network-based or device-based
22421.
D. feature-based or attachment-based
22422.
81. The level of ____ within an IM program brings up the issue of privacy.
22423. A. users signed up
22424.
B. advertising
22425.
C. technology
22426.
D. presence awareness
22427.
82. One reason behind the success of the Internet is the fact that it is built on
_____.
22428. A. open standard
22429.
B. user trust
22430.
C. safe architecture
22431.
D. solid ground
22432.
83. Which of the following is not an additional revenue opportunity offered by
advance messaging services?
22433. A. electronic commerce
22434.
B. advertising
22435.
C. targeted marketing
22436.
D. taxes
22437.
84. ADSL increases existing twisted-pair access capacity by _____.
22438. A. twofold
22439.
B. threefold
22440.
C. thirtyfold
22441.
D. fiftyfold

22442.
85. What appears to be the practical limit for analog modems over a standard
telephone?
22443. A. 33 kbps
22444.
B. 28.8 kbps
22445.
C. 24 kbps
22446.
D. 19.2 kbps
22447.
86. Which of the parameters will need to be incorporated into next generation
billing solutions to calculate new 3G charges?
22448. A. number of packets
22449.
B. location
22450.
C. quality of service
22451.
D. any of these
22452.
87. Which of the following is not considered as 3G service?
22453. A. streaming video
22454.
B. wireless voice
22455.
C. interactive shopping
22456.
D. on-line banking and stock trading
22457.
88. ATM timing requirements feature _____ elements.
22458. A. 3
22459.
B. 4
22460.
C. 32
22461.
D. 64
22462.
89. All are required for broadband media services delivery over IP except:
22463. A. high bandwidth
22464.
B. a broadband connection
22465.
C. a narrowband connection
22466.
D. DSL
22467.
90. All are network components for broadband media services except
22468. A. video server
22469.
B. catv box
22470.
C. set-top box
22471.
D. video encoder
22472.
91. A Cable Modem Termination System (CMTS) provides an Ethernet network
with a geographic reach of up to _____.
22473. A. 1 mile
22474.
B. 10 miles
22475.
C. 100 miles
22476.
D. any of these
22477.
92. The upstream data channel specification requirement for cable modem feature
which of the following?
22478. A. 64 and 256 QAM formats
22479.
B. data rates from 320 kbps to 10 Mbps
22480.
C. 6 MHz-occupied spectrum that coexists with other signals in the cable
plant
22481.
D. all of the above
22482.
93. DWDM enables different formats, such as ______, to be transmitted over the

optical layer.
22483. A. IP and ATM
22484.
B. ATM and SONET
22485.
C. SONET and SDH
22486.
D. all of the above
22487.
94. Future DWDM terminals will have the capacity to transmit _____ volumes of
an encyclopedia in one second.
22488. A. 90
22489.
B. 250
22490.
C. 1500
22491.
D. 90000
22492.
95. DWDM allows the transmission of _____ over the optical layer.
22493. A. voice and e-mail
22494.
B. multimedia and video
22495.
C. data
22496.
D. all of the above
22497.
96. Which of the following is expected to take the largest share of the three DSL
varieties?
22498. A. SDSL
22499.
B. HDSL
22500.
C. ADSL
22501.
D. IDSL
22502.
97. Which of the following standards defines procedures and message sequences
used for fax communications?
22503. A. T.10
22504.
B. T.30
22505.
C. T.37
22506.
D. T.38
22507.
98. The _____ is a particular set of standards that allows the internetworking of
products from different vendors. It usually embodies a fiber-optic ring that will permit
transmission in both directions.
22508. A. local-area network (LAN)
22509.
B. wide-area network (WAN)
22510.
C. synchronous optical network (SONET)
22511.
D. common channel signaling network
22512.
99. H.255 can be defined as _____.
22513. A. media stream control
22514.
B. control signaling
22515.
C. call signaling
22516.
D. media stream transport
22517.
100. H.245 can be defined as _____.
22518. A. media stream control
22519.
B. control signaling
22520.
C. media stream transport
22521.
D. registration and admission
22522.
101. H.323 can be defined as _____.

22523. A. multimedia services over B-ISDN
22524.
B. multimedia services over guaranteed QoS networks
22525.
C. multimedia services over packet networks
22526.
D. multimedia services over SCN
22527.
102. H.320 can be defined as _____.
22528. A. multimedia services over B-ISDN
22529.
B. multimedia services over guaranteed QoS networks
22530.
C. multimedia services over packet networks
22531.
D. multimedia services over ISDN
22532.
103. One of the major advances that result from implementing intelligent
networks is that _____.
22533. A. computers no longer have control over the network
22534.
B. wide-area service outages are much less likely
22535.
C. services can be adapted to user needs more efficiently
22536.
D. service providers are now limited to a single equipment provider
22537.
104. The development of the intelligent network places increased emphasis on a
consistent _____.
22538. A. switch model
22539.
B. network model
22540.
C. intelligence model
22541.
D. call model
22542.
105. How many layers are there to the PCS air resistance?
22543. A. 1
22544.
B. 2
22545.
C. 3
22546.
D. 4
22547.
106. What is the maximum possible number of characters in a PCS message?
22548. A. 64
22549.
B. 256
22550.
C. 1021
22551.
D. 239
22552.
107. Signaling units are broken up into units of how many bits?
22553. A. 8
22554.
B. 16
22555.
C. 32
22556.
D. 64
22557.
108. Two digital signals whose transitions occur at almost the same rate are
_____.
22558. A. asynchronous
22559.
B. synchronous
22560.
C. plesiochronous
22561.
D. none of these
22562.
109. Which of the following are not basic SONET network elements?
22563. A. switch interference
22564.
B. digital loop carrier
22565.
C. service control point

22566.
D. add/drop multiplexer
22567.
110. Higher-order SDH cross-connects route what entity?
22568. A. 1.5 Mbps
22569.
B. ATM cells
22570.
C. management data channels
22571.
D. payload within 155 Mbps
22572.
111. Scrambling is used in SDH for which reason?
22573. A. to randomize the bit sequence for better transmission performance
22574.
B. to reduce the power consumption of equipment
22575.
C. to allow for upgrade to higher bit rates
22576.
D. to prevent unauthorized access
22577.
112. FDMA allocated ____ users per channel.
22578. A. 1
22579.
B. 3
22580.
C. 6
22581.
D. 10
22582.
113. The G.723.1 specification for audio codecs, recommended by the VoIP
Forum, requires:
22583. A. 6.3 kbps
22584.
B. 7.9 kbps
22585.
C. 8.4 kbps
22586.
D. 10.4 kbps
22587.
114. ITU’s H.320 standard defines the protocols for transporting voice, data and
video over;
22588. A. PSTN
22589.
B. ISDN networks
22590.
C. the public internet
22591.
D. GSM network
22592.
115. Which of the following is not a layer in the WAP gateway stack?
22593. A. WDP
22594.
B. context manager
22595.
C. TCP
22596.
D. WSP
22597.
116. Queries to the HLR are performed to find the location of the serving MSC in
_____.
22598. A. TDMA
22599.
B. CDMA
22600.
C. GSM
22601.
D. all of the above
22602.
117. The SMSC delivers messages directly to the _____.
22603. A. HLR
22604.
B. VLR
22605.
C. MSC
22606.
D. BSC
22607.
118. Which of the following pairs of technologies use IS-41?
22608. A. GSM and TDMA

22609.
B. CDMA and GSM
22610.
C. TDMA and CDMA
22611.
D. all of the above
22612.
119. Which of the following technologies has significant advantages in mediumdensity and high-density population areas because it is capable of carrying higher levels
of traffic, provides better voice quality, and can transmit data at higher rates?
22613. A. GSM
22614.
B. PCS
22615.
C. CT-2
22616.
D. DECT
22617.
120. IS-41 is a standard currently being embraced by wireless providers because it
encourages _____.
22618. A. increased network capabilities
22619.
B. paging
22620.
C. roaming
22621.
D. all of the above
22622.
22623.
22624.
22625.
22626.
22627.
22628.
22629.
22630.
22631.
22632.
22633.
22634.
22635.
22636.
22637.
22638.
22639.
22640.
22641.
22642.

22643. MULTIPLE CHOICE QUESTIONS IN

22644. CELLULAR
TELEPHONY

22645.

Electronics Systems and Technologies
22646. By
22647.

Melvin C. Arceo
22648.
22649.
22650.
22651.
22652.
22653.
22654.
22655.
22656.
22657.

22658. ENCODED BY:
22659. LAQUI, Louise Ruelyn J.
22660.
Base station transmitter output power of Improved Mobile System (IMTS)
22661.
22662.
A.100-W to 200-W range
22663.
B. 200-W to 300-W range
22664.
C. 150-W to 400-W range
22665.
D. 300-W to 400-W range
22666.
22667.
The chipping rate of WCDMA (UMTS)
22668.
22669.
A. 3.84 Mcps
22670.
B. 3.6484 Mcps
22671.
C. 1.25 Mcps
22672.
D. 1.22 Mcps
22673.
22674.
A technique that divides the group of channels into smaller groupings or
segments of mutually exclusive frequencies; cell sites, which are within the reuse
distance is assigned their own segment of the channel group
22675.
sectoring
dualization
partitioning
segmentation
22676.
22677.
The actual voice channel where mobile users communicate directly with other
mobile or wireline subscriber through the base station
22678.
control channel
forward channel
reverse channel
voice channel

22679.
22680.
22681.

Supervisory Audio Tones(SAT) have the following frequencies except:
5940 Hz
5970 Hz
6000 Hz
6030 Hz

22682.
22683.
22684.

Each cell site contains a
Repeater
Control computer
Direct-link to a branch exchange
Touch-tone processor

22685.
22686.
22687.

A class II mobile phone using AMPS has an ERP of
-6dBW
-4dBW
2dBW
6dBW

22688.
22689.
of
22690.

The wideband designation in Wideband-CDMA (WCDMA) denotes a bandwidth
2.5 MHz
3 MHz
4.5 MHz
5MHz

22691.
22692.
An automobile travels at 60km/hr. Find the time between fades in the car uses a
PCS phone at 1900 MHz.
22693.
2.4 ms
3.4 ms
4.7 ms
5.1 ms
22694.
22695.
A cellular system is capable of coping with handoffs once every 2 minutes.
Suppose this system is in the city with maximum car speeds of 65km/hr. What is the
maximum cell radius for this urban system?
22696.
1.08 km
3 km
5 km
2 km

22697.
22698.
22699.

How wide is the spectrum bandwidth of a single GSM carrier?
16 kHz
200 kHz
100 kHz
50 kHz

22700.
22701.
Changing the time order of digital information before transmission to reduce the
effect of burst errors in the channel.
22702.
progression
interleaving
epoch
raking
22703.
22704.
The bandwidth of WCDMA is ___ times larger than GSM.
22705.
5
15
20
25
22706.
22707.
It is the process in which the same set of frequencies can be allocated to more
than one cell, provided that the cells are separated by a sufficient distance
22708.
frequency reuse
handoff
clustering
radio survey
22709.
22710.
A connection is momentarily broken during the cell-to-cell transfer is called
______.
22711.
hard handoff
soft handoff
medium handoff
light handoff
22712.
22713.
Transmission from mobile stations to the base stations is called
22714.
forward link
reverse link
control link
user link
22715.

22716.
It is a database in the PCS network that stores information about the user,
including home subscription information and what supplementary services the user is
subscribed to.
22717.
visitor location register
home location register
equipment identification register
authentication register
22718.
22719.
Determine the transmit power for a CDMA mobile unit that is receiving a signal
from the base station at 100 dBm
22720.
12 dBm
24 dBm
36 dBm
14 dBm
22721.
22722.
When transmitting digital information, voice transmission is inhibited, this is
called ______.
22723.
quieting
muting
blank-and-burst
any of these
22724.
22725.
A metropolitan area of 1000 square km is to be covered by cells with a radius of 2
km. How many cell sites would be required, assuming hexagonal cells?
22726.
72
73
74
75
22727.
22728.
Refers to a land station in a maritime mobile services
22729.
coast station
maritime station
coast earth station
ship earth station
22730.
22731.
Class of orthogonal spreading coded used in CDMA communication.
22732.
Color code
Walsh code
PCS code
CDMA

22733.
22734.
In a spread spectrum system, the tendency for a stronger signals to interfere with
the reception of weaker signals.
22735.
near-far field
near-far effect
direct-sequence
spread-spectrum
22736.
22737.
Macrocells have base stations transmit power between _____.
22738.
3W to 7W
1W to 6W
2W to 8W
0.1W to 5W
22739.
22740.
It is when the area of a cell, or independent component coverage areas of a
cellular system, is further divided, thus creating more cell areas.
22741.
cell splitting
cell clustering
cell partitioning
cell sectoring
22742.
22743.
It is when a mobile unit moves from one cell to another from one company's
service area to another company's service area.
22744.
roaming
handoff
handover
paging
22745.
22746.
It is a 34-bit binary code that represents the 10-digit telephone number
22747.
electronic serial number
system identification
digital color code
mobile identification number
22748.
22749.
The bandwidth of WCDMA is __ times larger than CDMAone.
22750.
4
5
6
7
22751.

22752.
22753.

Receive channel 22 is 870.66 MHz. Receive channel 23 is
870.36 MHz
870.63 MHz
870.96 MHz
870.69 MHz

22754.
22755.
22756.

In mobile wireless communication, the radio equipment and the propagation path
FSL
air interface
direct link
mobile interface

22757.
22758.
The signaling fone may be transmitted on the voice channel during a call in what
frequency?
22759.
25 kHz
20 kHz
15 kHz
10 kHz
22760.
22761.
Station in the mobile service not intended to be used while in motion.
22762.
base station
fixed station
coast station
land station
22763.
22764.
In the GSM system, a "smart card" containing all user information, which is
inserted into the phone before use.
22765.
IMSI
IMEI
IMTS
SIM
22766.
22767.
Determine the number of channels per cluster of a cellular telephone area
comprised of 10 clusters with seven cells in each cluster and 10 channels in each cell.
22768.
70 channels per cluster
700 channels per cluster
7000 channels per cluster
7 channels per cluster
22769.
22770.
Determine the channel capacity if 7 macrocells with 10 channels per cell is split

into 4 minicells
22771.
120 channels per area
360 channels per area
280 channels per area
460 channels per area
22772.
22773.
Technique of spread spectrum that breaks message into fixed-size blocks of data
with each block transmitted in sequence except on the different carrier frequency.
22774.
spread spectrum
time-division multiplexing
frequency-hopping
direct sequence
22775.
22776.
A base and mobile is separated by 5 km. What is the propagation time for a signal
traveling between them?
22777.
14.5 usec
18.9 usec
20.8 usec
16.7 usec
22778.
22779.
A digital identification associated with a cellular system
22780.
MIN
ESN
SAT
SIM
22781.
22782.
A new regulation issued by the National Telecommunications Commission
providing for the guideline for mobile personal communication having a global coverage
using satellite.
22783.
NMT
GMPCS
GSM
TACS
22784.
22785.
The following are the typical cluster size except
22786.
3
7
12
15
22787.

22788.
Provides a centralized administration and maintenance point for the entire
network end interfaces with the public telephone network through the telephone wireline
voice trunks and data links
22789.
PSTN
MTSO
central offices
MSC
22790.
22791.
It is a digital telephone exchange located in the MTSO that is the heart of a
telephone system
22792.
mobile switching center
electronic switching center
gateway switching center
electronic mobile switching center
22793.
22794.
A database in the PCS network that stores information pertaining to the
identification and type of equipment that exist in the mobile unit.
22795.
visitor location register
home location register
equipment identification register
authentication register
22796.
22797.
When a signal from a mobile cellular unit drops below a certain level, what action
occurs?
22798.
The unit is "handed off" to a closer cell.
The call is terminated.
The MTSO increases power level.
The cell site switches antenna.
22799.
22800.
A method of transmitting data on AMPS cellular telephone voice channels that are
temporary unused.
22801.
cellular digital packet data
digital color code
control mobile attenuation code
electronic serial code
22802.
22803.
A vehicle travels through a cellular system at 100 km per hour. Approximately
how often will handoffs occur if the cell radius is 10 km.
22804.
12 min
14 min

16 min
18 min
22805.
22806.
22807.

In the GSM system, a telephone number that is unique to a given user, worldwide.
IMTS
IMEI
IMSI
SIM

22808.
22809.
An area divided into hexagonal shapes that fit together to form a honeycomb
pattern is called ______.
22810.
cluster
transport area
cell
area of responsibility
22811.
22812.
Determine the channel capacity of a cellular telephone area comprised of twelve
macrocell with ten channels per cell
22813.
12 channels per area
120 channels per area
1200 channels per area
12000 channels per area
22814.
22815.
Transmission from base stations to mobile stations is called ____.
22816.
forward link
reverse link
control link
user link
22817.
22818.
The output power of a cellular radio is controlled by the
22819.
user or caller
cell site
called party
MTSO
22820.
22821.
EDGE channel size is about
22822.
250 kHz
200 kHz
150 kHz
100 kHz

22823.
22824.
A switching facility connecting cellular telephone base stations to each other and
to the public switched telephone network.
22825.
MTSO
MSC
VLR
AuC
22826.
22827.
A radio land station in the land mobile service
22828.
land station
ship earth station
base station
mobile station
22829.
22830.
Transmission of brief text messages, such as pages or e-mail, by cellular radio or
PCS.
22831.
SMS
MMS
paging
raking
22832.
22833.
The point when the cell reaches maximum capacity occurs when the number of
subscribers wishing to place a call at any given time equals the number of channels in the
cell
22834.
saturation
blocking traffic
maximum traffic load
any of these
22835.
22836.
In IS-41 standard, it is a process where the mobile unit notifies a serving MTSO
of its presence and location through a base station controller.
22837.
dependent registration
autonomous registration
air interface
BTS to BSC interface
22838.
22839.
Cellular telephones use which operation?
22840.
simplex
half-duplex
full-duplex

triplex
22841.
22842.
A receiver capable of receiving several versions of the same signal with different
arrival times and combining the received versions into a single signal with better quality
22843.
scanners
rake receivers
mobile subscriber unit
mobile stations
22844.
22845.
In CMTS, the most important database for GSM is ____.
22846.
VLR
HLR
BTS
AUC
22847.
22848.
In CMTS, the number of duplex voice channels for AMPS is ____.
22849.
676
285
395
790
22850.
22851.
A geographic cellular radio coverage area containing three of more group of cells
22852.
cluster
cell
radio channel
MSC/VLR area
22853.
22854.
A flawless cell-to-cell transfer is called ____.
22855.
hard handoff
soft handoff
heavy handoff
light handoff
22856.
22857.
The bit length of System Identification (SID)
22858.
32
15
10
8
22859.
22860.
The RF power output of a transmitter in a cellular mobile telephone system

authorized by NTC for use in the Philippines.
22861.
20.5 dBm
31.5 dBm
34.8 dBm
22.1 dBm
22862.
22863.
A class III mobile phone using AMPS has an ERP of
22864.
4W
1.6 W
600 mW
1.4 W
22865.
22866.
____ is measuring the propagated field strength over the projected service area.
22867.
radio monitoring
radio sounding
radio survey
none of these
22868.
22869.
Transmission of data in two directions on a channel by using different time slots
for each directions.
22870.
time-division multiplexing
time-division multiple access
time-division duplexing
time-division
22871.
22872.
When the cluster size is reduced with a constant cell size, what happens to the
total channel capacity?
22873.
decreases
increases
stays constant
depends on the number of cell cites
22874.
22875.
The transfer of a mobile unit from one base station's control to another base
station's control
22876.
handoff
paging
roaming
dualization
22877.
22878.
What is the frequency deviation of AMPS?

22879.
12 kHz
6 kHz
3 kHz
18 kHz
22880.
22881.
The bit length of Digital Color Code (DCC)
22882.
2
3
4
5
22883.
22884.
A transmit channel has a frequency of 837.6 MHz. The receive channel frequency
is
22885.
729.6 MHz
837.6 MHz
867.6 MHz
882.6 MHz
22886.
22887.
A frequency-hopping spread-spectrum system hops to each of 100 frequencies
every 10 seconds. How long does it spread on each frequency?
22888.
0.2 sec/hop
0.4 sec/hop
0.3 sec/hop
0.1 sec/hop
22889.
22890.
What is the transmission rate of a GSM cellular system?
22891.
128 kbps
240 kbps
64 kbps
270 kbps
22892.
22893.
A card with an embedded integrated circuit that can be used for functions such as
storing subscriber information for a PCS system.
22894.
smart card
SIM
Intelligent card
Credit card
22895.
22896.
It is a means of avoiding full-cell splitting where the entire area would otherwise
need to be segmented into smaller cells.

22897.
segmentations
dualization
sectoring
splitting
22898.
22899.
A channel used for transferring control and diagnostic information between
mobile users and a central cellular telephone switch through the base stations.
22900.
forward channel
voice channel
control channel
reverse channel
22901.
22902.
It is the provision of voice communication using internet protocol technology,
instead of traditional circuit switched technology.
22903.
WAP
GPRS
VOIP
WIFI
22904.
22905.
Determine the total number of channel capacity of a cellular telephone area
comprised of 10 clusters with seven cells in each cluster and 10 channels in each cell.
22906.
7 channels
70 channels
700 channels
7000 channels
22907.
22908.
Technique used in spread spectrum that adds a high-bit rate pseudorandom code
to a low bit rate information signal to generate a high-bit rate pseudorandom signal
closely resembling noise that contains both the original data signal and pseudorandom
noise.
22909.
direct-sequence
frequency-division multiplexing
frequency hopping
CDMA
22910.
22911.
Refers to the first generation of local loop system in telecommunication
technology
22912.
TACS
DECT
Analog cellular

GSM
22913.
22914.
An information sent by the base station in a cellular radio system set the power
level of the mobile transmitter.
22915.
cellular digital packet data
digital color code
control mobile attenuation code
electronic serial code
22916.
22917.
A 32-bit binary code permanently assigned to each of the mobile unit
22918.
supervisory audio tone
station class mark
electronic serial number
visitor location register
22919.
22920.
It serves as central control for all users within that cell
22921.
base stations
antennas
transceivers
mobile subscriber units
22922.
22923.
What modulation technique is used by Advanced Mobile Phone System (AMPS)
22924.
WBFM
VSB
NBFM
FSK
22925.
22926.
A database in the PCS network that stores information about subscribers in a
particular MTSO serving area
22927.
international mobile subscriber identification
visitor location register
home location register
authentication register
22928.
22929.
In cellular phone, a memory location that stores the telephone number(s) to be
used on the system.
22930.
EPROM
UVPROM
EEPROM
NAM

22931.
22932.
A province in the Philippines has an area 2000 sq. kms. It has to be covered by a
cellular mobile telephone service using cells with a radius of 3 kms. Assuming hexagonal
cells, find the number of cell sites needed.
22933.
100
500
166
145
22934.
22935.
The modulation technique used by GSM cellular system.
22936.
QAM
Phase Shift Keying
Gaussian Minimum Shift Keying
Frequency Shift Keying
22937.
22938.
Microcells have base stations transmit power between ____.
22939.
0.4W to 0.7W
1W to 6W
0.5W to 8W
0.1W to 1W
22940.
22941.
Determine the receive carrier frequencies for AMPS channel 3 and channel 991
22942.
870.09 MHz and 869.04 MHz
879.09 MHz and 859.04 MHz
869.09 MHz and 870.04 MHz
869.04 MHz and 870.09 MHz
22943.
22944.
Decreasing co-channel interference while increasing capacity by using directional
antenna is called ____.
22945.
clustering
splitting
partitioning
sectoring
22946.
22947.
Soft handoff normally takes ____ of time delay.
22948.
400 ms
300 ms
200 ms
100 ms
22949.

22950.
Component of a cellular telephone network that manages each of the radio
channels at each site.
22951.
base station controllers
base transceiver stations
mobile switching center
mobile telephone switching center
22952.
22953.
The bit length of Station Class Mark (SCM).
22954.
4
5
8
10
22955.
22956.
The master control center for a cellular telephone system is the
22957.
Cell site
MTSO
Central office
Branch office
22958.
22959.
The maximum frequency deviation of an FM cellular transmitter is
22960.
6 kHz
12 kHz
30 kHz
45 kHz
22961.
22962.
A receiver channel has a frequency is 872.4 MHz. to develop an 82.2 MHz IF, the
frequency synthesizer must apply an local oscillator signal of ____ (The local oscillator is
usually higher than the receive frequency)
22963.
790.2 MHz
827.4 MHz
954.6 MHz
967.4 MHz
22964.
22965.
A class I mobile phone using AMPS has an ERP of
22966.
6 dBW
2 dBW
-2 dBW
-6 dBW
22967.
22968.
A mobile telephone service using trunked channels but not cellular nature

22969.
IMTS
MTSO
IMSI
IMEI
22970.
22971.
The GSM cellular radio system uses GMSK in a 200-kHz, with a channel data
rate of 270.833 kbps. Calculate the frequency shift between mark and space in kHz?
22972.
135.4165
153.6514
315.4651
513.1654
22973.
22974.
A cellular system is capable of coping with a handoffs once every 2 minutes.
What is the maximum cell radius if the system must be capable of working with cars
traveling at highway speed of 120 km/hr?
22975.
3 km
1 km
4 km
6 km
22976.
22977.
Radio communication operation service between mobile and land stations or
between mobile stations.
22978.
land mobile
land mobile satellite service
mobile service
maritime mobile service
22979.
22980.
A multiple access technique used in GSM cellular system.
22981.
FDMA
CDMA
TDMA
TACS
22982.
22983.
This is the Nordic analog mobile radio telephone system originally used in
Scandinavia
22984.
NMT
GSM
PCN
PCS
22985.

22986.
The combination of the mobile cellular phone and the cell-site radio equipment is
known as
22987.
forward link
base transceiver station
air interface
base station controller
22988.
22989.
The duplex frequency of GSM
22990.
40 MHz
80 MHz
120 MHz
30 MHz
22991.
22992.
The channel separation of GSM channel
22993.
270 kHz
200 kHz
120 kHz
60 kHz
22994.
22995.
The number of control channels for AMPS
22996.
25
23
21
19
22997.
22998.
The modulation technique used audio signal for TACS
22999.
FM
FSK
TFSK
QAM
23000.
23001.
Speech coding rate for GSM
23002.
80 kbps
25 kbps
21 kbps
13 kbps
23003.
23004.
Number of channels for GSM
23005.
333

666
124
248
23006.
23007.
It is a database that contains information about the identity of mobile equipment
that prevents calls from stolen, unauthorized, or defective mobile stations.
23008.
Equipment Identity Register
Authentication Center
Home Location Register
Visitor Location Register
23009.
23010.
It provides all the control functions and physical links between the MSC and BTS
23011.
OSS
OMC
MSC
BSC
23012.
23013.
It is the functional entity from which the operator monitors and controls the
mobile communication system.
23014.
Operation and Maintenance System
Mobile Switching Center
Gateway Mobile Switching Center
Operation and Support System
23015.
23016.
A node in the switching system of GSM that provides integrated voice, fax and
data messaging.
23017.
Gateway Mobile Switching Center
Mobile Service Node
GSM Internetworking Unit
Message Center
23018.
23019.
It is a node in the switching system of GSM that handles mobile intelligent
network services.
23020.
Message Center
Gateway Mobile Switching Center
Mobile Service Unit
Mobile Switching Center
23021.
23022.
The modulation scheme used for NADC
23023.
NFSK

Quarterwavelength Shifted QPSK
GFSK
Trellis coding
23024.
23025.
23026.
23027.
23028.
23029.
23030.
23031.
23032.

23033. MULTIPLE CHOICE QUESTIONS IN

23034. SATELLITE
COMMUNICATIONS
23035.

Electronics Systems and Technologies
23036. By
23037.

Melvin C. Arceo
23038.
23039.
23040.
23041.
23042.
23043.
23044.
23045.
23046.

23047. ENCODED BY:
23048. LAQUI, Louise Ruelyn J.
23049.
It is a celestial body that orbits around a planet.
23050.
23051. Primary body
23052. Satellite
23053. Heavenly bodies
23054. Quasars
23055.
23056.
It is a position and timing service that is available to all GPS users on a
continuous, worldwide basis with no direct charge.

23057.
23058. PPI
23059. PPS
23060. SPS
23061. SSP
23062.
23063.
The geometric shape of a non-circular orbit of a satellite is ____.
23064.
23065. Ellipse
23066. Parabolic
23067. Hyperbolic
23068. Paraboloid
23069.
23070.
The circuit that provides channelization in a transponder is the
23071.
23072. Mixer
23073. Local oscillator
23074. Bandpass filter
23075. HPA
23076.
23077.
The three axes referred to the three-axis attitude stabilization are; except
23078.
23079. Pitch
23080. Yaw
23081. Roll
23082. Speed
23083.
23084.
A ground station is operating to a geostationary satellite at a 5 degrees angle of
elevation. Calculate the round-trip time between ground station to satellites in a
geostationary orbit.
23085.
23086. 456.45 ms
23087. 275.58 ms
23088. 137.79 ms
23089. 126.89 ms
23090.
23091.
The escape velocity of the earth is approximately
23092.
23093. 30,000 km/hr
23094. 25,000 mi/hr
23095. 35,000 m/s
23096. 25,000 km/hr
23097.
23098.
A satellite radio repeater is called ____.
23099.
23100. Repeater

23101. Transponder
23102. Satellite
23103. Mixer
23104.
23105.
Calculate the angle of declination for an antenna using a polar mount at a latitude
of 45 degrees.
23106.
23107. 3.2 degrees
23108. 1.3 degrees
23109. 4.2 degrees
23110. 6.81 degrees
23111.
23112.
The time transfer accuracy used with reference to the Universal Transmitter
Mercator Grid is ____.
23113.
23114. UTC
23115. UTMG
23116. GMT
23117. UTM
23118.
23119.
It is caused by the inertia of the satellite balanced by the earth’s gravitational pull.
23120.
23121. Centrifugal force
23122. Centripetal force
23123. Speed
23124. Earth’s rotation
23125.
23126.
In satellites, it includes control mechanism that support the payload operation.
23127.
23128. Bus
23129. Payload
23130. Ground segment
23131. Space segment
23132.
23133.
A satellite transmitter operates at a 4 GHz with a transmitter power of 7W and an
antenna gain of 40 dBi. The receiver has antenna gain of 30 dBi, and the path length is
40,000 km. calculate the signal strength at the receiver.
23134.
23135. -88 dBm
23136. -98 dBm
23137. -77 dBm
23138. -79.8 dBm
23139.
23140.
The satellite subsystem that monitors and controls the satellite is the
23141.
23142. Propulsion system

23143. Power subsystem
23144. Communications subsystem
23145. Telemetry, tracking, and command subsystems
23146.
23147.
Standard positioning service has time transfer accuracy to Universal Transfer
Mercator Grid within ____.
23148.
23149. 140 nanoseconds
23150. 340 nanoseconds
23151. 230 nanoseconds
23152. 530 nanoseconds
23153.
23154.
A satellite remains in orbit because the centrifugal force caused by its rotation
around the Earth is counterbalanced by Earth’s ____.
23155.
23156. Centripetal force
23157. Inertia
23158. Gravitational pull
23159. Speed
23160.
23161.
A TVRO installation for use with C-band satellite (download frequency at 4
GHz), has a diameter of about 3.5 meters and an efficiency of 60%. Calculate the gain.
23162.
23163. 41 dB
23164. 19 dB
23165. 29 dB
23166. 9 dB
23167.
23168.
Which of the following is not a typical output from the GPS receiver?
23169.
23170. Latitude
23171. Speed
23172. Altitude
23173. Longitude
23174.
23175.
The law that states that a satellite will orbit a primary body following an elliptical
path.
23176.
23177. 1st law of Kepler
23178. 2nd law of Kepler
23179. 3rd law of Kepler
23180. 4th law of Kepler
23181.
23182.
Telephone communication takes place between two earth stations via a satellite
that is 40,000 km from each station. Suppose Bill, at station 1, asks a question and
Sharon, at station 2, answers immediately, as soon as she hears the question. How much

time elapses between the end of Bill’s question and the beginning of Sharon’s reply, as
heard by Bill?
23183.
23184. 0.26 sec
23185. 3.2 sec
23186. 0.52 sec
23187. 1.6 sec
23188.
23189.
In GPS, it is accomplished by manipulating navigation message orbit data
(epsilon) and/or the satellite clock frequency (dither).
23190.
23191. Selective availability
23192. Reverse error notification
23193. Forward error notification
23194. Two dimensional reporting
23195.
23196.
The modulation normally used with digital data is
23197.
23198. AM
23199. FM
23200. SSB
23201. QPSK
23202.
23203.
Kepler’s 2nd law is known as
23204.
23205. Law of gravity
23206. Law of areas
23207. Newton’s law of motion
23208. Harmonic law
23209.
23210.
A receiving antenna with a gain of 40 dB looks at a sky with a noise temperature
of 15 K. the loss between the antenna and the LNA input, due to the feedhorn is 0.4 dB,
and the LNA has a noise temperature of 40K. Calculate the G/T?
23211.
23212. 13.4 dB
23213. 39 dB
23214. 20.6 dB
23215. 11.2 dB
23216.
23217.
The operational satellites of Navstar GPS are revolving around Earth in ____
orbital planes.
23218.
23219. 4
23220. 3
23221. 5
23222. 6

23223.
23224.
Kepler’s 3rd law is also known as
23225.
23226. Law of gravity
23227. Law of areas
23228. Newton’s law of motion
23229. Harmonic law
23230.
23231.
The basic technique used to stabilize a satellite is
23232.
23233. Gravity-forward motion balance
23234. Spin
23235. Thruster control
23236. Solar panel orientation
23237.
23238.
Calculate the length of the path to a geostationary satellite from an earth station
where the angle of elevation is 30 degrees.
23239.
23240. 55 x 10^3 km
23241. 13 x 10^3 km
23242. 23 x 10^3 km
23243. 39 x 10^3 km
23244.
23245.
Navstar GPS is a ____.
23246.
23247. LEO
23248. MEO
23249. HEO
23250. GEO
23251.
23252.
The satellite is orbiting in the same direction as the Earth’s rotation and at angular
velocity greater than that of the Earth.
23253.
23254. Retrograde
23255. Synchronous
23256. Posigrade
23257. Asynchronous
23258.
23259.
Find the orbital period of the satellite in a circular orbit 500 km above the Earth’s
surface
23260.
23261. 1.6 hrs
23262. 3.2 hrs
23263. 2.4 hrs
23264. 6.4 hrs
23265.

23266.
Satellite orbiting in the opposite direction as the Earth’s rotation and at angular
velocity less than that of the Earth
23267.
23268. Asynchronous
23269. Synchronous
23270. Posigrade
23271. Retrograde
23272.
23273.
A transponder that demodulates the baseband signals and then demodulates a
carrier is known as ____ transponder.
23274.
23275. Single-conversion
23276. Double-conversion
23277. Regenerative
23278. Degenerative
23279.
23280.
Low Earth Orbit (LEO) satellite orbits around the earth at a height of
approximately ____.
23281.
23282. 3000 miles
23283. 1000 miles
23284. 575 miles
23285. 370 miles
23286.
23287.
Power amplification in a transponder is usually provided by
23288.
23289. klystron
23290. TWT
23291. Transistor
23292. Magnetron
23293.
23294.
Which of the following clocks is developed for Galileo satellite?
23295.
23296. Cesium Atomic Frequency Standard
23297. Rubidium Atomic Frequency Standard
23298. Ruby Atomic Frequency Standard
23299. Hydrogen Frequency Standard
23300.
23301.
Master control station of GPS is located in ____.
23302.
23303. Colorado
23304. California
23305. Alaska
23306. New York
23307.
23308.
Medium Earth Orbit (MEO) satellite orbits around the earth at a height

approximately ____.
23309.
23310. 3,000 miles to 6,000 miles
23311. 4,000 miles to 8,000 miles
23312. 6,000 miles to 12,000 miles
23313. 8,000 miles to 10,000 miles
23314.
23315.
A satellite stays in orbit because the following two factors are balanced
23316.
23317. Satellite weight and speed
23318. Gravitational pull and inertia
23319. Centripetal force and speed
23320. Satellite weight and the pull of the moon and sun
23321.
23322.
A ____ circuit in the transponder performs the frequency conversion.
23323.
23324. HPA
23325. Mixer
23326. Local oscillator
23327. LPA
23328.
23329.
Geosynchronous satellites are high-altitude earth-orbit satellites with heights
about ____.
23330.
23331. 22,300 miles
23332. 21,000 miles
23333. 8,000 miles
23334. 10,400 miles
23335.
23336.
The input circuit to a transponder is the ____.
23337.
23338. BPF
23339. HPA
23340. LPA
23341. Any of these
23342.
23343.
The access scheme used by GPS
23344.
23345. FDMA
23346. OFDMA
23347. TDMA
23348. CDMA
23349.
23350.
The point in an orbit which is located farthest from earth
23351.
23352. Perigee

23353. Apogee
23354. Line of apsides
23355. Point of shoot
23356.
23357.
Using very narrow beamwidth antennas to isolate signals on the same frequency
is known as ____.
23358.
23359. Spatial isolation
23360. Footprint
23361. Frequency reuse
23362. Boresight
23363.
23364.
The point in an orbit which is located closest to Earth
23365.
23366. Point of shoot
23367. Apogee
23368. Line of apsides
23369. Perigee
23370.
23371.
The most popular satellite frequency range is 4 to 6 GHz and is called the ____
band.
23372.
23373. C
23374. L
23375. Ka
23376. Ku
23377.
23378.
All satellites rotate around the earth in an orbit that forms a plane that passes
through the center of gravity of earth called ____.
23379.
23380. Focus
23381. Geocenter
23382. Orbit
23383. Center
23384.
23385.
In satellite communications, the type of modulation used in voice and video
signals is
23386.
23387. AM
23388. FM
23389. SSB
23390. QPSK
23391.
23392.
In satellite communications, type of orbit which is virtually all orbits except those
travel directly above the equator or directly over the North or the South poles.
23393.

23394. Equatorial orbit
23395. Polar orbit
23396. Geosynchronous orbit
23397. Inclined orbit
23398.
23399.
A common up-converter and down-converter IF insatelite communications is
23400.
23401. 36 MHz
23402. 40 MHz
23403. 70 MHz
23404. 500 MHz
23405.
23406.
It is the angle between the earth’s equatorial plane and the orbital plane of the
satellite measured counterclockwise.
23407.
23408. Angle of elevation
23409. Angle of azimuth
23410. Angle of inclination
23411. Angle of tetrahedron
23412.
23413.
Which of the following types of HPA is not used in earth stations?
23414.
23415. TWT
23416. Klystron
23417. Transistors
23418. Magnetron
23419.
23420.
Galileo satellite’s mass is ____.
23421.
23422. 880 kg
23423. 675 kg
23424. 900 kg
23425. 540 kg
23426.
23427.
The point where a polar or inclined orbit crosses the equatorial plane traveling
from north to south
23428.
23429. Ascending node
23430. Line of nodes
23431. Descending node
23432. Diagonal nodes
23433.
23434.
The receive GCE system in an earth station performs what function/s
23435.
23436. Modulation and multiplexing
23437. Up conversion

23438. Demodulation and demultiplexing
23439. Down conversion
23440.
23441.
The term generally associated with the table showing the position of a heavenly
body on the number of dates in a regular sequence.
23442.
23443. Astronomical almanac
23444. Smith
23445. Ephemeris
23446. Space reporting
23447.
23448.
The point where a polar or inclined orbit crosses the equatorial plane traveling
from south to north.
23449.
23450. Ascending node
23451. Descending node
23452. Diagonal node
23453. Inclined node
23454.
23455.
The line joining the ascending and descending node is called ____.
23456.
23457. Line of apsides
23458. Line of nodes
23459. Line of shoot
23460. Any of these
23461.
23462.
When the satellite rotates in an orbit directly above the equator, usually in circular
pattern. This type of orbit is called ____.
23463.
23464. Polar orbit
23465. Synchronous orbit
23466. Geosynchronous satellite
23467. Equatorial orbit
23468.
23469.
The Navstar GPS satellite system was declared fully operational as of ____.
23470.
23471. April 17, 1995
23472. April 24, 1995
23473. April 27, 1995
23474. April 10, 1995
23475.
23476.
The HPAs in most satellites are
23477.
23478. TWTs
23479. Vacuum tubes
23480. Klystrons

23481. Magnetrons
23482.
23483.
The physical location of a satellite is determined by its
23484.
23485. Distance from the earth
23486. Latitude and longitude
23487. Reference to the stars
23488. Position relative to the sun
23489.
23490.
When the satellite rotates in a path that takes it over the north and south poles in
an orbit perpendicular to the equatorial plane. This type of orbit is called ____.
23491.
23492. Inclined orbit
23493. Polar orbit
23494. Geosynchronous orbit
23495. Diagonal orbit
23496.
23497.
The azimuth angles and the angle of elevation is collectively known as ____.
23498.
23499. Antennas look angles
23500. Antennas see angles
23501. Antennas keep angles
23502. Antennas satellite angles
23503.
23504.
The point on the surface of the Earth directly below the satellite.
23505.
23506. Satellite point
23507. Latitude
23508. Longitude
23509. Subsatellite point
23510.
23511.
It is the vertical angle formed between the direction of travel of an
electromagnetic wave radiated from an earth station antenna pointing directly toward a
satellite and the horizontal plane.
23512.
23513. Angle of depression
23514. Angle of inclination
23515. Angle of elevation
23516. Angle of azimuth
23517.
23518.
The unique number used to encrypt the signal from that of the GPS satellite.
23519.
23520. SV
23521. UV
23522. PRN
23523. ESN

23524.
23525.
The minimum acceptable angle of elevation
23526.
23527. 6 degrees
23528. 4 degrees
23529. 5 degrees
23530. 7 degrees
23531.
23532.
It is the horizontal angular distance from a reference direction either the southern
or northern most point of the horizon.
23533.
23534. Angle of elevation
23535. Latitude
23536. Longitude
23537. Azimuth
23538.
23539.
It is defined as the horizontal pointing angle of an earth station antenna.
23540.
23541. Angle of inclination
23542. Azimuth angle
23543. Latitude
23544. Longitude
23545.
23546.
Determines the farthest satellite away that can be seen looking east or west of the
earth station’s longitude
23547.
23548. Radio horizon
23549. Optical horizon
23550. Terrestrial limits
23551. Limits of visibility
23552.
23553.
The spatial separation of a satellite is between ____.
23554.
23555. 3 to 6 degrees
23556. 1 to 2 degrees
23557. 5 to 8 degrees
23558. 8 to 16 degrees
23559.
23560.
The geographical representation of a satellite antenna’s radiation pattern is called
a ____.
23561.
23562. Field intensity
23563. Footprint
23564. Radiation propagation
23565. Polarization
23566.

23567.
The GPS satellite identification which is assigned according to the order of the
vehicle’s launch.
23568.
23569. SV
23570. EV
23571. PRN
23572. ESN
23573.
23574.
The smallest beam of a satellite that concentrates their power to very small
geographical areas.
23575.
23576. Hemispherical beam
23577. Global beam
23578. Spot beam
23579. Any of these
23580.
23581.
Satellite’s radiation pattern that typically target up to 20% of the Earth’s surface.
23582.
23583. Hemispherical beam
23584. Global beam
23585. Spot beam
23586. Any of these
23587.
23588.
The key electronic component in a communications satellite is the
23589.
23590. Telemetry
23591. Command and Control system
23592. On-board computer
23593. Transponder
23594.
23595.
The radiation pattern that has a satellite’s antenna beamwidth of 17 degrees and
are capable of covering approximately 42% of the earth’s surface.
23596.
23597. Hemispherical beam
23598. Earth beam
23599. Spot beam
23600. Any of these
23601.
23602.
The first active satellite
23603.
23604. Moon
23605. Sputnik I
23606. Score
23607. Echo
23608.
23609.
Sputnik I transmitted telemetry information for

23610.
23611. 1 week
23612. 21 days
23613. 15 days
23614. 30 days
23615.
23616.
The US counterpart of Sputnik I
23617.
23618. Syncom
23619. Telstar
23620. Echo
23621. Explorer I
23622.
23623.
Explorer I lasted for ____.
23624.
23625. 5 months
23626. 6 months
23627. 12 months
23628. 2 months
23629.
23630.
Navstar GPS satellite grouping that can operate continuously for 180 days
between uploads from the ground.
23631.
23632. Block III
23633. Block IIa
23634. Block II
23635. Block IIR
23636.
23637.
It was the first artificial satellite used for relaying terrestrial communications
23638.
23639. Score
23640. Explorer I
23641. Sputnik I
23642. Syncom I
23643.
23644.
Which of the following satellite rebroadcast President Eisenhower’s 1958
Christmas message?
23645.
23646. Telstar I
23647. Telstar II
23648. Echo
23649. Score
23650.
23651.
The satellite or space segment of Navstar GPS is consist of ____ operational
satellites.
23652.

23653. 30
23654. 24
23655. 14
23656. 20
23657.
23658.
It was the first satellite to accomplish transatlantic transmission.
23659.
23660. Courier
23661. Echo
23662. Telstar
23663. Syncom
23664.
23665.
It is the first transponder-type satellite
23666.
23667. Telstar I
23668. Sputnik I
23669. Syncom
23670. Courier
23671.
23672.
The first active satellite to simultaneously receive and transmit radio signals.
23673.
23674. Telstar I
23675. Telstar II
23676. Intelsat
23677. Syncom
23678.
23679.
The satellite communications channel in a transponder are defined by the
23680.
23681. LNA
23682. Bandpass filter
23683. Mixer
23684. Input signals
23685.
23686.
The satellite that was damaged by radiation from a newly discovered Van Allen
Belts and consequently lasted for two weeks.
23687.
23688. Telstar I
23689. Telstar II
23690. Intelsat
23691. Syncom
23692.
23693.
As the height of a satellite orbit gets lower, the speed of the satellite
23694.
23695. Increases
23696. Decreases
23697. Remains the same

23698. None of the above
23699.
23700.
The satellite that was lost in space in its first attempt to place it in a
geosynchronous orbit.
23701.
23702. Syncom I
23703. Telstar I
23704. Telstar II
23705. Courier
23706.
23707.
Intelsat I which was the first commercial telecommunications satellite is called
____.
23708.
23709. Domsat
23710. Molniya
23711. Early bird
23712. Courier
23713.
23714.
Block II Navstar GPS satellites can operate for approximately ____ between the
receiving updates and corrections from the control segment of the system.
23715.
23716. 5.5 days
23717. 3.5 days
23718. 6 days
23719. 7 days
23720.
23721.
The angle of inclination of a satellite in polar orbit is nearly ____.
23722.
23723. 45 degrees
23724. 90 degrees
23725. 30 degrees
23726. 60 degrees
23727.
23728.
It is the time it takes earth to rotate back to the same constellation
23729.
23730. Revolution
23731. Rotation
23732. Sidereal period
23733. Year
23734.
23735.
Satellites with orbital pattern like Molniya are sometimes classified as
23736.
23737. LEO
23738. MEO
23739. GEO
23740. HEO

23741.
23742.
The process of maneuvering a satellite within a preassigned window is called
23743.
23744. Satellite keeping
23745. Station controlling
23746. Station keeping
23747. Satellite controlling
23748.
23749.
Navstar GPS satellite grouping capacble of detecting certain error conditions, then
automatically transmitting a coded message indicating that it is out of service.
23750.
23751. Block I
23752. Block IIa
23753. Block II
23754. Block IIR
23755.
23756.
Galileo Satellites has a lifespan of ____.
23757.
23758. > 12 years
23759. > 15 years
23760. > 20 years
23761. > 25 years
23762.
23763.
The height of a satellite in a synchronous equatorial orbit is
23764.
23765. 100 mi
23766. 6800 mi
23767. 22,300 mi
23768. 35,860 mi
23769.
23770.
An orbit that is 36,000 km away from the geocenter of the earth is called
23771.
23772. Geosynchronous orbit
23773. Clarke orbit
23774. Clarke belt
23775. Any of these
23776.
23777.
The main function of a communications satellite is as
23778.
23779. Repeater
23780. Reflector
23781. Beacon
23782. Observation platform
23783.
23784.
Navstar GPS grouping intended to be used only for self testing.
23785.

23786. Block I
23787. Block III
23788. Block II
23789. Block IIR
23790.
23791.
It is the direction of maximum gain of the earth station antenna
23792.
23793. Footprint
23794. Boresight
23795. Angle of elevation
23796. Angle of azimuth
23797.
23798.
A circular orbit around the equator with 24-h period is called
23799.
23800. Elliptical orbit
23801. Geostationary orbit
23802. Polar orbit
23803. Transfer orbit
23804.
23805.
A classification of satellite that uses the angular momentum of its spinning body
to provide roll and yaw stabilization.
23806.
23807. Roll stabilizer satellite
23808. Yaw stabilizer satellite
23809. Spinner stabilizer satellite
23810. Three-axis stabilizer satellite
23811.
23812.
Most satellites operate in which frequency band?
23813.
23814. 30 to 300 MHz
23815. 300 MHz to 3 GHz
23816. 3 to 30 GHz
23817. Above 300 GHz
23818.
23819.
The method of assigning adjacent channels different electromagnetic polarization
is called
23820.
23821. Frequency reuse
23822. Polarization
23823. Multi-accessing
23824. Interference
23825.
23826.
It implies that more than one user has an access to one or more radio channels
23827.
23828. Co-channel interference
23829. Satellite multi-accessing

23830. Frequency reuse
23831. Diversity
23832.
23833.
The main power sources for a satellite are
23834.
23835. Batteries
23836. Solar cells
23837. Fuel cells
23838. Thermoelectric generators
23839.
23840.
A type of satellite’s multiple-accessing method that allows all users continuous
and equal access of the entire transponder bandwidth by assigning carrier frequencies on
a temporary basis using statistical assignment process.
23841.
23842. TDMA
23843. FDMA
23844. DAMA
23845. CDMA
23846.
23847.
Batteries are used to power all satellite subsystems
23848.
23849. All the time
23850. Only during emergencies
23851. During eclipse periods
23852. To give the solar arrays a rest
23853.
23854.
The highly accurate timing clocks onboard the GPS satellite.
23855.
23856. Plutonium clocks
23857. Cesium atomic clocks
23858. Hydrogen clocks
23859. Fossil clocks
23860.
23861.
It is defined as the art or science of plotting, ascertaining, or directing the course
of movement.
23862.
23863. Ranging
23864. Detection
23865. Navigation
23866. Driving
23867.
23868.
Galileo satellite system is positioned in ____.
23869.
23870. 5 circular orbits
23871. 3 circular orbits
23872. 2 circular orbits

23873. 6 circular orbits
23874.
23875.
The maximum height of an elliptical orbit is called the
23876.
23877. Perigee
23878. Apex
23879. Zenith
23880. Apogee
23881.
23882.
The most ancient and rudimentary method of navigation is ____.
23883.
23884. Wandering
23885. Celestial navigation
23886. Piloting
23887. Radio navigation
23888.
23889.
The jet thrusters are usually fired to
23890.
23891. Main attitude
23892. Put the satellite into transfer orbit
23893. Inject the satellite into the geosynchronous orbit
23894. Bring the satellite back to earth
23895.
23896.
A method of navigation where direction and distance are determined from
precisely timed sightings of celestial bodies, including the stars and the moon.
23897.
23898. Electronic navigation
23899. Heavenly navigation
23900. Radio navigation
23901. Celestial navigation
23902.
23903.
Navstar satellite takes approximately ____ hours to orbit Earth.
23904.
23905. 20
23906. 6
23907. 12
23908. 18
23909.
23910.
A method of navigation where it fixes a position or direction with respect to
familiar, significant landmarks such as railroad tracks, water towers, barns, mountain
peaks and bodies or water.
23911.
23912. Dead reckoning
23913. Radio navigation
23914. Wandering
23915. Piloting

23916.
23917.
How can multiple earth stations share a satellite on the same frequencies?
23918.
23919. Frequency reuse
23920. Multiplexing
23921. Mixing
23922. They can’t
23923.
23924.
A navigation technique that determines position by extrapolating a series of
measured velocity increments.
23925.
23926. Piloting
23927. Wandering
23928. Radio navigation
23929. Dead reckoning
23930.
23931.
A geostationary satellite
23932.
23933. Is motionless in space (except for its gain)
23934. Is not really stationary at all, but orbits the Earth within a 24-hr period
23935. Appears stationary over the Earth’s magnetic pole
23936. Is located at a height of 35,800 km to ensure global coverage
23937.
23938.
The average elevation of Navstar GPS satellite is ____ statue miles above the
Earth.
23939.
23940. 6724
23941. 7689
23942. 5978
23943. 9476
23944.
23945.
Most commercial satellite activity occurs in which band(s)
23946.
23947. L
23948. C and Ku
23949. X
23950. S and P
23951.
23952.
Indicate the correct statement regarding satellite communications
23953.
23954. If two earth stations do not face a common satellite, they should communicate via
a double-satellite hop.
23955. Satellites are allocated so that it is impossible for two earth stations not to face the
same satellite.
23956. Collocated earth stations are used for frequency diversity.
23957. Satellite earth station must have as many receive chains as there are carriers

transmitted to it.
23958.
23959.
Satellite used for intercontinental communications are known as
23960.
23961. Comsat
23962. Domsat
23963. Marisat
23964. Intelsat
23965.
23966.
Identical telephone numbers in different parts of the country are distinguished by
their
23967.
23968. Language digits
23969. Access digits
23970. Area codes
23971. Central office codes
23972.
23973.
The GPS satellites has an angle of elevation at the ascending node of ____ with
respect to the equatorial plane.
23974.
23975. 30 degrees
23976. 55 degrees
23977. 50 degrees
23978. 45 degrees
23979.
23980.
Telephone traffic is measured
23981.
23982. With echo cancellers
23983. By the relative congestion
23984. In terms of the grade of service
23985. In erlangs
23986.
23987.
Indicate which of the following is not a submarine cable
23988.
23989. TAT-7
23990. INTELSAT V
23991. ATLANTIS
23992. CANTAT 2
23993.
23994.
The typical bandwidth of a satellite band is
23995.
23996. 36 MHz
23997. 40 MHz
23998. 70 MHz
23999. 500 MHz
24000.

24001.
The operational satellites of Navstar GPS are revolving around Earth in orbital
planes are approximately ____ degrees apart with ____ satellites in each plane.
24002.
24003. 60, 4
24004. 30, 5
24005. 50, 5
24006. 40, 3
24007.
24008.
Indicate which of the following is an American domsat system
24009.
24010. INTELSAT
24011. TELSTAR
24012. COMSAT
24013. INMARSAT
24014.
24015.
Which of the following is not usually a part of a transponder?
24016.
24017. LNA
24018. Mixer
24019. Modulator
24020. HPA
24021.
24022.
Who is the oldest man in space?
24023.
24024. John Glenn
24025. Neil Armstrong
24026. Yuri Gagarin
24027. Edwin Aldrin
24028.
24029.
It refers to the satellite orientation with respect to the earth.
24030.
24031. Satellite’s attitude
24032. Satellite position
24033. Satellite location
24034. Satellite orbit
24035.
24036.
Precise positioning service has time transfer accuracy to UTC within
24037.
24038. 100 nanoseconds
24039. 300 nanoseconds
24040. 200 nanoseconds
24041. 400 nanoseconds
24042.
24043.
The fully deployed Galileo satellite system consists of ____ satellites.
24044.
24045. 27 operational + 3 active spares

24046. 26 operational + 4 active spares
24047. 28 operational + 2 active spares
24048. 25 operational + 5 active spares
24049.
24050.
Galileo satellite is ____.
24051.
24052. Medium Earth Orbit (MEO)
24053. Low Earth Orbit (LEO)
24054. Geosynchronous Earth Orbit (GEO)
24055. Highly Elliptical Orbit (HEO)
24056.
24057.
Galileo satellites are at circular planes at ____ altitude above Earth.
24058.
24059. 23,500 mi
24060. 36,500 km
24061. 35,800 mi
24062. 23,222 km
24063.
24064.
Galileo satellites are inclined at the orbital planes of ____ with reference to the
equatorial plane.
24065.
24066. 64 degrees
24067. 17 degrees
24068. 56 degrees
24069. 34 degrees
24070.
24071.
24072.
24073.
24074.
24075.
24076.
24077.
24078.
24079.
24080.
24081.
24082.
24083.
24084.
24085.

24086.
24087.
24088.
24089.
24090.
24091.
24092.

24093. MULTIPLE CHOICE QUESTIONS IN

24094. ANTENNA
24095.

Electronics Systems and Technologies
24096. By
24097.

Melvin C. Arceo
24098.
24099.
24100.
24101.
24102.
24103.
24104.
24105.
24106.
24107.
24108.

24109. ENCODED BY:
24110. LORENZO, Luer Breech B.
24111. It is a metallic conductor system capable of radiating and capturing electromagnetic
energy.
transmission lines
antenna
waveguides
load
24112.
24113. A directional antenna with two or more elements is known as
folded dipole
ground plane
loop
array
24114.
24115. The ratio of the focal length to the diameter of the mouth of the parabola is called _____.
aperture

focal point
foci
major axis
24116.
24117. The impedance of a dipole is about
50-ohm
73-ohm
93-ohm
300-ohm
24118.
24119. A special type if transmission lint that consists of a conducting metallic tube through
which high-frequency electromagnetic energy is propagated.
medium
microstrip
stripline
waveguide
24120.
24121. Calculate the angle of declination for an antenna using a polar mount at a latitude of 45
degrees.
3.2 degrees
1.3 degrees
4.2 degrees
6.81 degrees
24122.
24123.
24124.
24125. The cone angle of the flare angle of a conical horn antenna is approximately
55 degrees
45 degrees
40 degrees
50 degrees
24126.
24127. Electrical energy that has escaped into free space in the form of transverse
electromagnetic waves
radio waves
frequency
signal
wavelength
24128.
24129. The length of the ground plane vertical at 146 MHz is
1.6 ft.
1.68 ft.
2.05 ft.
3.37 ft.
24130.
24131. Using a small reflector to beam waves to the larger parabolic reflector is known as

focal feed
horn feed
cassegrain feed
coax feed
24132.
24133. The plane parallel to the mutually perpendicular line in the electric and magnetic fields is
called _____
wavefront
point source
isotropic source
rays
24134.
24135. What is the beamwidth of a parabolic antenna with a diameter of 5 meters and an
operating frequency to 10 GHz?
0.5 degrees
0.675 degrees
0.348 degrees
3.48 degrees
24136.
24137.
24138. The horizontal radiation pattern of a dipole is a
circle
figure of eight
clover leaf
narrow beam
24139.
24140. The size of the antenna is inversely proportional to _____
frequency
power
radiation resistance
wavelength
24141.
24142. A popular half-wavelength antenna is the
ground plane
end-fire
collinear
dipole
24143.
24144. Calculate the gain of a parabolic antenna using a 2.5-m radius dish operating at 10 GHz.
166.673 dB
83.7 dB
52.2 dB
45.6 dB
24145.
24146. It is the ratio of the radiated to the reflected energy
radiation resistance

radiation efficiency
radiation constant
radiation antenna
24147.
24148. The feed mechanism in a parabolic antenna that radiates the electromagnetic energy
primary antenna
reflectors
secondary antenna
focal point
24149.
24150.
24151.
24152.
24153.
24154. It is a polar diagram representing field strengths or power densities at various angular
relative to an antenna
sidelobe
front lobe
radiation pattern
radiation constant
24155.
24156. For a transmit antenna with a radiation resistance of 72 ohms, an effective antenna
resistance of 8 ohms, a directivity gain of 20 and an input power of 100W, determine the
antenna gain.
12.55 dB
10.43 dB
11.21 dB
9.78 dB
24157.
24158. The radiation pattern plotted in terms of electric field strength or power density
absolute radiation pattern
relative radiation pattern
absolute front lobe pattern
absolute sidelobe pattern
24159.
24160. Calculate the characteristic impedance of a quarter-wavelength section used to connect a
300-ohm antenna to a 75-ohm line
150 ohms
120 ohms
130 ohms
110 ohms
24161.
24162. Plots of field strength or power density with respect to the value at a reference point
absolute frontlobe pattern
relative radiation pattern
relative frontlobe pattern

relative radiation pattern
24163.
24164. What must be the height nof a vertical radiator one-half wavelength high if the operating
frequency is 1100 kHz?
120 m
136 m
115 m
124 m
24165.
24166. Lobes adjacent to the front lobe
diagonal lobes
side lobes
front lobes
back lobes
24167.
24168. Lobes in a directional exactly opposite of the front lobe
side lobes
adjacent lobes
front lobes
back lobes
24169.
24170. Calculate the efficiency of an antenna that has a radiation resistance of 73 ohms and an
effective dissipation resistance of 5 ohms.
98.3 %
93.6 %
90.7 %
95.5 %
24171.
24172. The line bisecting the major lobe, or pointing from the center of the antenna in the
direction of maximum radiation is called _____.
line of shoot
diagonal shoot
bisecting shoot
antenna shoot
24173.
24174. The ammeter connected at the base of a Marconi antenna has a certain reading. If this
reading is increased 2.77 times, what is the increase in output power?
3.45
1.89
2.35
7.67
24175.
24176. Refers to a field pattern that is close to the antenna
induction field
far field
radiation

capture field
24177.
24178. A half-wave dipole is driven a 5-W signal at 225MHz. A receiving dipole 100 km.
Calculate the received power into a 73-ohm receiver.
23.5 pW
7.57 pW
5.64 pW
1.26 pW
24179.
24180. It is the resistance that, if it replaced the antenna, would dissipate exactly the same
amount of power that the antenna radiates.
directivity gain
antenna efficiency
radiation resistance
antenna resistance
24181.
24182. What is the effective radiated power of a television broadcast station if the output of the
transmitter is 1000W, antenna transmission line loss is 50W, and the antenna power gain is 3.
1250 W
2370 W
2130 W
2850 W
24183.
24184. It is the ratio of the power radiated by an antenna to the sum of the power radiated and
the power dissipated.
radiation resistance
coupling resistance
antenna efficiency
antenna beamwidth
24185.
24186. It is the ratio of the power radiated by the antenna to the total input power.
antenna efficiency
reflection coefficient
standing wave ratio
radiation resistance
24187.
24188.
24189.
24190.
24191.
24192. If a 500-kHz transmitter of a constant power produces field strength of 100 µV/m at a
distance of 100 mil from the transmitter, what would be the field strength at a distance of 200
mi from the transmitter?
45µV/m
100 µV/m
50 µV/m

35 µV/m
24193.
24194. An antenna that transmits or receives equally well in all directions is said to be ______.
omnidirectional
bi-directional
unidirectional
quadsidirectional
24195.
24196. It is the ratio of the power density radiated in a particular direction to the power density
radiated to the same point by a reference antenna, assuming both antennas are radiating the
same amount of power.
power gain
directive gain
total gain
system gain
24197.
24198. If the field intensity of 25 mV/m develops 2.7 V in a certain antenna, what is its effective
height?
110 m
100 m
98 m
108 m
24199.
24200. The magnetic field of an antenna is perpendicular to the earth. The antenna’s polarization
______.
is vertical
is horizontal
is circular
cannot be determined from the information given
24201.
24202.
24203.
24204.
24205. If the power of a 500-kHz transmitter is increased from 150W to 300W, what would be
the percentage change in field intensity at a given distance from the transmitter?
141 %
150 %
100 %
133 %
24206.
24207. It is the same with directive gain except that the total power fed to the antenna is used and
the antenna efficiency is taken into account.
system gain
power gain
directive gain
total gain

24208.
24209. A ship-radio telephone transmitter operates on 2738 kHz. At a certain point distant from
the transmitter, the 2738-kHz signal is measured field at 147 mV/m, the second harmonic
field at the same decibels, how much has the harmonic emission been attenuated below the
2738-kHz fundamental?
43.2 dB
51.2 dB
35.1 dB
25.1 dB
24210.
24211. It is the equivalent power that an isotropic antenna would have to radiate to achieve the
same power density in the chosen direction at a given point as another antenna.
EIRP
ERP
IRL
RSL
24212.
24213. When energy is applied to the antenna at a point of high-circulating current.
voltage-fed antenna
power-fed antenna
current-fed antenna
impedance-fed antenna
24214.
24215.
24216.
24217.
24218. For a transmitter antenna with a power gain of 10 and an input power of 100W, determine
the EIRP in watts.
30 dBW
40 dBW
50 dBW
20 dBW’
24219.
24220. If the energy is applied at the geometrical center of antenna, the antenna is said to be
________.
center-fed
end-fed
quarterwave-fed
halfwave-fed
24221.
24222. For a transmit antenna with a power gain of 10 and an input power of 100W, determine
the power density at a point 10 km from the transmit antenna
0.574 µW/m2
0.796 µW/m2
1.24 µW/m2
0.981 µW/m2

24223.
24224. For a transmit antenna with a radiation resistance of 72 ohms, an effective antenna
resistance of 8 ohms, a directive gain of 20 and an input power of 100W, determine the
antenna efficiency.
90 %
96 %
98 %
96 %
24225.
24226. The field surrounding the antenna do not collapse their energy back into the antenna but
rather radiate it out into space.
induction field
near field
radiation field
magnetic field
24227.
24228.
24229.
24230.
24231. For receive power density of 10µW/m2 and a receive antenna with a capture area of 0.2
m2, determine the captured power.
0.5 µW
2 µW
1 µW
1.5 µW
24232.
24233. The property of interchangeability for the transmitting and receiving operations is known
as _____.
efficiency
accuracy
reciprocity
polarization
24234.
24235. The length of a doublet at 27 MHz is _____.
8.67 ft.
17.3 ft.
18.2 ft.
34.67 ft.
24236.
24237. Refers to the orientation of the electric field radiated from an antenna.
efficiency
beamwidth
polarization
accuracy
24238.
24239. At frequencies below 2 MHz, what type of antenna is usually used?

Marconi antenna
Hertzian antenna
Herzt antenna
Elementary doublet
24240.
24241. The angular separation between two half-power points in the major lobe of the antenna’s
plane radiation pattern.
bandwidth
polarization
efficiency
beamwidth
24242.
24243.
24244. Hertz antenna are predominantly used with frequencies above
3 MHz
4 MHz
5 MHz
2 MHz
24245.
24246. Defined as the frequency range over which antenna operation is satisfactory.
beamwidth
channel
bandwidth
baseband
24247.
24248. One of the following is not a omnidirectional antenna.
half-wave dipole
log-periodic
discone
marconi
24249.
24250. The point on the antenna where the transmission line is connected is called _____.
center feed
end feed
feedpoint
voltage feed
24251.
24252. A popular vertical antenna is the _____.
collinear
dipole
ground plane
broadside
24253.
24254. The discone antenna is
a useful direction-finding antenna
used as a radar receiving antenna

circularly polarized like other circular antennas
useful as a UHF receiving antenna
24255.
24256.
24257.
24258.
24259.
24260. The feedpoint presents and ac load to the transmission line called
antenna output impedance
antenna input impedance
feedpoint impedance
center feed impedance
24261.
24262. A helical antenna is used for satellite tracking because of its
circular polarization
maneuverability
broad bandwidth
good front to back ratio
24263.
24264. The simplest type of antenna
elementary doublet
half-wave dipole
quarterwave dipole
5/8 wavelength dipole
24265.
24266. Zoning is used with a dielectric antenna in order to
reduce the bulk of the lens
increase the bandwidth of the lens
permit pin-point focusing
correct the curvature of the wavefront from a horn that is too short
24267.
24268. It is an electrically short dipole.
short dipole
quarterwave dipole
half-wave dipole
yagi antenna
24269.
24270. Cassegrain feed is used with parabolic reflector to
increase the gain of the system
increase the bandwidth of the system
reduce the size of the main reflector
allow the feed to be placed at a convenient point
24271.
24272.
24273.
24274.

24275.
24276. The half-wave dipole is generally referred to as ______.
Yagi antenna
Hertzian antenna
Marconi antenna
Hertz antenna
24277.
24278. Top loading is sometimes used with an antenna in order to increase its
effective height
bandwidth
beamwidth
input capacitance
24279.
24280. What is the directivity of a Hertz antenna?
1.64
2.18
2.15
1.75
24281.
24282. The standard reference antenna for the directive gain is the _____.
infinitesimal dipole
isotropic antenna
elementary doublet
half-wave dipole
24283.
24284. An antenna which is one-quarter wavelength long, mounted vertically with the lower end
either connected directly to ground or grounded through the antenna coupling network.
loop antenna
hertzian antenna
monopole antenna
turnstile antenna
24285.
24286. An antenna that is circularly polarized is the
helical
small circular loop
parabolic reflector
Yagi-Uda
24287.
24288.
24289.
24290.
24291. It is a wire structure placed below the antenna and erected above the ground.
ground plane
counterpoise
ground lines
top hat

24292.
24293. Which of the following terms does not apply to the Yagi-Uda array
good bandwidth
parasitic elements
folded dipole
high gain
24294.
24295. It effectively cancels out the capacitance component of the antenna input impedance.
ground plane
top hat
loading coil
shunt capacitance
24296.
24297. Indicate which of the following reasons for the use of an earth mat with antennas is false:
impossibility of a good ground conduction
provision of an earth for the antenna
protection of personnel working underneath
improvement of the radiation pattern of the antenna
24298.
24299. A metallic array that resembles a spoke wheel placed at the top of an antenna, it increases
the shunt capacitance to ground reducing the overall antenna capacitance.
loading coil
top loading
series capacitance
series inductors
24300.
24301. Indicate the antenna that is not wideband;
discone
folded dipole
helical
Marconi
24302.
24303.
24304.
24305.
24306. It is formed when two or more antenna elements are combined to form a single antenna.
antenna elements
antenna arrays
driven elements
parasitic elements
24307.
24308. One of the following is not a reason for the use of an antenna coupler:
to make the antenna look resistive
to provide the output amplifier with the correct load impedance
to discriminate against harmonics
to prevent reradiation of local oscillators

24309.
24310. It is an individual radiator, such as half or quarter-wave dipole
antenna element
antenna array
reflector
director
24311.
24312. Indicate which of the following reasons for using counterpoise with antennas is false:
impossibility of a good ground connection
protection of personnel working underneath
provision of an earth for the antenna
rockiness of the ground itself
24313.
24314. Type of antenna element that is directly connected to the transmission lines and receives
from or is driven by the source.
driven array
parasitic array
driven element
parasitic element
24315.
24316. Which of the following antennas is best excited from a waveguide?
biconical
horn
helical
discone
24317.
24318.
24319.
24320.
24321. Type of antenna element that is not connected to the transmission lines.
parasitic array
driven array
parasitic array
parasitic element
24322.
24323. One of the following is very useful as a multiband HF receiving antenna. This is the:
conical horn
folded dipole
log-periodic
square loop
24324.
24325. A parasitic element that is longer than the driven element from which it receives energy.
driven element
director
parasitic element
reflector

24326.
24327. One of the following consists of nonresonant antennas.
rhombic antenna
folded-dipole antenna
end-fire antenna
broadside antenna
24328.
24329. A parasitic element that is shorter than its associated driven element.
redirector
director
reflector
parasitic element
24330.
24331. An ungrounded antenna near the ground.
acts as a single antenna near the ground
is unlikely to need an earth mat
acts as an antenna array
must be horizontally polarized
24332.
24333.
24334.
24335.
24336. It is a non resonant antenna capable of operating satisfactory over a relatively wide
bandwidth, making it ideally suited for HF transmission.
turnstile antenna
loop antenna
rhombic antenna
discone antenna
24337.
24338. A wide-bandwidth multielement driven array is the _____.
end-fire
log-periodic
yagi
collinear
24339.
24340. It is a linear array antenna consisting of a dipole and two or more parasitic elements: one
reflector and one director.
broadside antenna
end-fire antenna
yagi-uda antenna
phased array antenna
24341.
24342. An antenna which is consists of a cone that is truncated in a piece of circular waveguide.
pyramidal horn antenna
circular horn antenna
rectangular horn antenna

conical horn antenna
24343.
24344. Which antenna has a unidirectional radiation pattern and gain?
dipole
ground plane
yagi
collinear
24345.
24346. An antenna formed by placing two dipoles at right angles to each other, 90 degrees out of
phase.
discone antenna
turnstile antenna
bicone antenna
5/8 wavelength shaped
24347.
24348.
24349. The radiation pattern of collinear and broadside antennas is _____.
omnidirectional
bi-directional
unidirectional
clover-leaf shaped
24350.
24351. What is the bandwidth ratio of log-periodic antenna?
10:1
5:1
20:1
1:10
24352.
24353. Which beam width represents the best antenna directivity
7 degrees
12 degrees
19 degrees
28 degrees
24354.
24355. It is a ration of the highest to the lowest frequency over which n antenna will satisfactoru
operate.
channel ratio
bandwidth ratio
reflection ratio
dynamic range
24356.
24357. An antenna has a power gain of 15. The power applied to the antenna is 32 W. The
effective radiated power is ______.
15 W
32 W
120 W

480 W
24358.
24359. It is simply a single-turn coil of wire that is significantly shorter than one wavelength and
carries RF current.
turnstile antenna
loop antenna
rhombic antenna
long-wire antenna
24360.
24361.
24362. A coax has an attenuation of 2.4 dB per 100 ft. The attenuation of 275 ft.
2.4 dB
3.3 dB
4.8 dB
6.6 dB
24363.
24364. It is a group of antennas or group of antenna arrays that when connected together,
function as a simple whose beamwidth and direction can be changed electronically withour
having to physically move any of the individual antennas or antenna elements within the
array.
end fire antenna
broadside antenna
phased array antenna
log-periodic antenna
24365.
24366. Conductors in multielement antennas that do not receive energy directly from the
transmission line are known as ______.
parasitic element
driven element
the boom
receptor
24367.
24368. It is a broad VHF or UHF antenna that is suited for applications for which radiating
circular rather than horizontal or vertical polarized electromagnetic waved are required
discone antenna
bicone antenna
log-periodic antenna
helical antenna
24369.
24370. Mode of propagation of helical antennas where electromagnetic radiation is in the
direction at right angles to the axis of the helix.
normal mode
axial mode
helix mode
helical mode
24371.

24372.
24373.
24374.
24375. Mode of propagation of helical antennas where radiation of the antenna in the axial
direction and produces a broadband relatively directional pattern
helical mode
normal mode
axial mode
helix mode
24376.
24377. In a Yagi antenna, maximum direction of radiation is toward the
director
driven element
reflector
sky
24378.
24379. It is defined as the ratio of the antenna maximum gain in the forward direction to its
maximum gain in its backward direction.
side-to-back ratio
front-to-side ratio
back-to-side ratio
front-to-back ratio
24380.
24381. The horizontal radiation pattern of a vertical dipole is a _____.
figure of eight
circle
narrow beam
clover leaf
24382.
24383. An antenna that provides extremely high gain and directivity and very popular for
microwave radio and satellite communications link
helical antenna
parabolic antenna
hyperbolic antenna
log-periodic antenna
24384.
24385. Part of a parabolic antenna that houses the primary antenna which radiates
electromagnetic waves toward the reflector.
feed mechanism
focal point
center feed
feed antenna
24386. It is a passive device that simply reflects the energy radiated by the feed mechanism into
a concentrated, highly directional emission in which the individual waved are all in phase
with each other.
director

parabolic segment
reflector
feed mechanism
24387.
24388. The energy near the edge of the parabolic dish that does not reflect but rather is diffracted
around the edge of the dish.
spillover
corona
dissipated power
copper loss
24389.
24390. Determines the angular aperture of the reflector, which indirectly determines how much
the primary radiation is reflected by the parabolic dish.
numerical aperture
V number
aperture number
aperture angle
24391.
24392. For a 2-m diameter parabolic reflector with 10W of power radiated by the feed
mechanism operating at 6 GHz with transmit antenna efficiency of 55 % and an aperture
efficiency of 55 % determine the beamwidth.
1.25 degrees
2.25 degrees
1.5 degrees
1.75 degrees
24393.
24394. Type of lead mechanism where the primary radiating source is located just behind a small
opening at the vertex of the paraboloid rather than at the focus.
cassegrain feed
center feed
horn feed
antenna feed
24395.
24396.
24397.
24398.
24399. Discone radiation pattern is
omnidirectional
unidirectional
figure of eight
bi-directional
24400.
24401. Which is properly terminated antenna?
dipole
marconi
hertz

rhombic
24402.
24403. An example of a Marconi antenna is _____.
quarter wave vertical tower
collinear
yagi
rhombic
24404.
24405. At the ends of a half-wave antenna, what values of current and voltage exist compared to
the remainder of the antenna?
minimum voltage and maximum current
minimum voltage and minimum current
equal voltage and current
maximum voltage and minimum current
24406.
24407. Radiation resistance is the ratio of ______.
radiated power to antenna center current
radiated power to the square of the antenna center current
voltage to any point of the antenna
square of voltage to thesquare of current at any point in the antenna
24408.
24409. Consists of basic antenna connected to a transmission line plus one or more additional
conductors
parasitic array
directors
driven array
reflectors
24410.
24411.
24412.
24413. Which of the following is not a driven array
yagi
broadside
collinear
end fire
24414.
24415. What is used to determine phase difference between two broadcast antennas?
a phase monitor
a frequency monitor
an amplitude monitor
a power monitor
24416.
24417. In antennas, which gives more forward gain?
reflector
driven element
parasitic element

director
24418.
24419. Which of the following is longer?
director
reflector
driven element
parasitic element
24420.
24421. Which is closer to the driven element?
parasitic element
driven element
director
reflector
24422.
24423. How much do they differ in length from a half-wavelength?
5%
10%
15%
20%
24424.
24425.
24426.
24427.
24428.
24429. How much move feed-point impedance does a folded-dipole have than normal dipole?
two times as much
three times as much
four times as much
five times as much
24430.
24431. How is it possible to produce 70-ohm twin lead?
by folding more parasitic element
by manufacturing
by increasing the radiation resistance
by increasing the length of the antenna
24432.
24433. With similar size parabolic, plane reflector, and corner-reflector beams, which has greates
gain?
plane reflector
parabolic
corner-reflector beam
V-beam
24434.
24435. With similar size, which has the narrowest lobes?
parabolic
V-beam

corner-reflector beam
plane reflector
24436.
24437. Why would the wires of V beam be closer together when used on higher frequencies?
main lobe lays further to wire
main lobe lays closer to wire
secondary lobes closer to wire
secondary lobes further to wire
24438.
24439. How is the V-beam made unidirectional?
impedance terminated
capacitive terminated
inductive terminated
resistor terminated
24440.
24441.
24442.
24443.
24444. Why might a rhombic be better than a V-beam?
it is resistor terminated
more acreage needed
less acreage needed
it is unidirectional
24445.
24446. Why is it usual rhombic nor frequency-sensitive?
unidirectional
terminated with its characteristic impedance
less acreage required
main lobe is greater than back lobe
24447.
24448. In what direction is the null of small diameter loop in relation to the plane of the loop?
45 degrees angle
180 degrees angle
360 degrees angle
90 degrees angle
24449.
24450. When is a loop unidirectional?
when horizontal
when vertical
when circular
when unidirectional
24451.
24452. Why are verticals sometimes top-loaded?
to resonate on high frequency
to decrease the electrical length
to resonate on low frequency

to look better
24453.
24454. Why is pi-network superior to direct coupling to an antenna?
reduce harmonic radiation
better frequency response
better radiation of energy
reduce power dissipation
24455.
24456.
24457.
24458.
24459.
24460. Why might L networks be used between an antenna and transmission line?
step impedance up
step impedance down
better radiation of energy
reduce power radiation
24461.
24462. Why are antenna ammeters often shorted out or disconnected from the antenna expect
when readings are desired?
to replace it with dummy
not to interfere with transmission
for proper reception of signals
to protect from lightning
24463.
24464. Device to split transmission line current to two or more antenna towers
splitter
coupler
isolator
phasor circuit
24465.
24466. What method can be used to determine the feed-point impedance of a vertical antenna?
resistance substitution
impedance matching
dissipated resistance measurement
grounding the antenna
24467.
24468. In what unit is field intensity measured/
volts
amperes
watts/m
mV/m
24469.
24470. How fast does low-frequency field strength attenuate?
directly proportional to distance
inversely proportional to distance

directly proportional to time
inversely proportional to time
24471.
24472.
24473.
24474. Under what condition might a harmonic of a transmission be heard at a distant point
when the fundamental cannot be?
when the carrier is weak
when fundamental is too weak
when harmonics are weak
when the harmonics are amplified
24475.
24476. Field gain can be measured in ______.
volts
dB
ohms
both volts and dB
24477.
24478. What is involved in the ERP of an antenna?
input power times field gain
input power squared times field gain
output power times field gain
output power squared times field gain
24479.
24480. Why do ground radials assure constant feed-point impedance?
virtual ground constant in any weather
ensure strength of signals
produce a signal image
creates good ground
24481.
24482. What feed requirements must be met to produce a circular radiation pattern when using
two crossed dipoles?
feed 180degrees apart electrically
feed 45 degrees apart electrically
feed 360 degrees apart electrically
feed 90 degrees apart electrically
24483.
24484. A section which would be a complete antenna by itself
bay
reflector
paraboloid
hyperboloid
24485.
24486.
24487. In what range of frequencies are most omnidirectional horizontally polarized antennas
used?

VHF and UHF
HF and VHF
UHF and HF
LF and MF
24488.
24489.
24490.
24491.
24492.
24493.
24494.
24495.
24496.
24497.
24498.
24499.
24500.
24501.
24502.
24503.
24504.
24505.
24506.
24507.
24508.
24509.

24510. MULTIPLE CHOICE QUESTIONS IN

24511. MICROWAVE
COMMUNICATIONS
24512.

Electronics Systems and Technologies
24513. By
24514.

24516.

Melvin C. Arceo
24515.

24517.
24518.
24519.
24520.
24521.
24522.
24523.

24524. ENCODED BY:
24525. LORENZO, Luer Breech B.
24526. IF repeaters are also called
heterodyne receiver
mixer/receiver
radio receiver
FM receiver
24527.
24528. It is the difference between the nominal output power of a transmitter and the minimum
input power required by a receiver
RSL
IRL
system gain
FSL
24529.
24530. A phenomenon whereby the frequency of a reflected of a reflected signal is shifted if
there is relative motion between the source and reflecting object.
Doppler effect
Hall effect
Marconi effect
Maxwell effect
24531.
24532. A ferrite is
a nonconductor with magnetic properties
an intermetallic compound with particularly good conductivity
an insulator which heavily attenuates magnetic fields
a microwave semiconductor invented by Faraday
24533.
24534. The primary purpose of the helix in a traveling-wave tube is to
prevent the electron beam from spreading in the long tube
reduce the axial velocity of the RF field
ensure the broadband operation
reduce the noise figure
24535.
24536. The attenuator is used in the travelling-wave tube to
help bunching
prevent oscillations
prevent saturation

increase the gain
24537.
24538.
24539.
24540. A magnetron is used only as
amplifier
oscillator
mixer
frequency multiplier
24541.
24542. A backward-wave oscillator is based on the
rising-sun magnetron
crossed-field amplifier
coaxial magnetron
traveling-wave tube
24543.
24544. Stripline and microstrip transmission lines are usually made with
coax
parallel lines
twisted pair
PCBs
24545.
24546. Which of the following is not a microwave tube?
Traveling-wave tube
Cathode-ray tube
Klystron
Magnetron
24547.
24548. Indicate which is not true. Compared with other types of radar, phased array radar has
the following advantages
very fast scanning
ability to track and scan simultaneously
circuit simplicity
ability to track many targets simultaneously
24549.
24550. Given the frequency and dimensions of 5 GHz and 7 cm by 9 cm respectively, the beam
of the pyramidal horn is about ______.
27 degrees
53 degrees
60 degrees
80 degrees
24551.
24552.
24553. The diameter of a parabolic reflector should be at least how many wavelengths at the
operating frequency?
1

2
5
10
24554.
24555. A type of microwave repeater where the received RF carrier is down-converted to an IF
frequency, amplified filtered and further demodulated to baseband.
RF repeater
IF repeater
baseband repeater
radio repeater
24556.
24557. In order to reduce cross-sectional dimensions, the waveguide to use is
circular
ridged
rectangular
flexible
24558.
24559. Indicate which one of the following applications or advantages of radar beacons is false:
target identification
navigation
very significant extension of the maximum range
more accurate tracking enemy targets
24560.
24561. Refers to more than one transmission path or method of transmission available between
transmitter and a receiver.
diversity
polarization
efficiency
accuracy
24562.
24563. A solution to the “blind speed” problem is to
change the Doppler frequency
vary the RF
use monopulse
use MTI
24564.
24565.
24566. A direct path that exist between the transmit and receive antennas
LOS
direct waves
space waves
terrestrial waves
24567.
24568. The function of the quartz delay line in an MTI radar is to
help in subtracting a complete scan from the previous scan
match the phase of the coho and the stalo

match the phase of the coho and the output oscillator
delay a sweep so that the next sweep can be subtracted from it
24569.
24570. Type of diversity where it modulates two different RF carrier frequencies with the same
IF intelligence, then transmitting both RF signals to a given destination.
polarization diversity
quad diversity
space diversity
frequency diversity
24571.
24572. The coho in MTI radar operates at the
intermediate frequency
transmitted frequency
received-frequency
pulse operation frequency
24573.
24574. Which type of diode does not ordinarily operate with reverse bias?
Varactor
IMPATT
Snapp-off
Tunnel
24575.
24576. What happens when a horn antenna is made longer?
gain increases
beam width decreases
bandwidth increases
bandwidth decreases
24577.
24578.
24579.
24580.
24581. A pyramidal horn used at 5 GHz has an aperture that is 7 cm by 9 cm. The gain is about
10.5 dB
11.1 dB
22.6 dB
35.8 dB
24582.
24583. Type of diversity where the output of the transmitter is fed to two or more antennas that
are physically separated by an appreciable wavelengths
quad diversity
wavelength diversity
space diversity
hybrid diversity
24584.
24585. The Doppler effect is used in (indicate the false statement)
moving-target plotting on the PPI

the MTI system
FM radar
CW radar
24586.
24587. A type of diversity where a single RF carrier is propagated with two different
electromagnetic polarization.
space diversity
wavelength diversity
polarization diversity
hybrid diversity
24588.
24589. The A scope displays
the target position and range
the target range, but not position
the target position, but not range
neither range nor position, but only velocity
24590.
24591. The glass tube of a TWT may be coated with aquadag to
help focusing
provide attenuation
improve bunching
increase gain
24592.
24593. Type of diversity which consists of a standard frequency diversity path where the two
transmitter/receiver pair at one end of the path are separated from each other and connected
to different antennas that are vertically separated as in space diversity
quad diversity
wavelength diversity
space diversity
hybrid diversity
24594.
24595. The biggest disadvantage of CW Doppler radar is that
it does not give the target velocity
it does not give the target range
a transponder is required at the target
it does not give the target position
24596.
24597. The combination of the frequency, space, polarization and receiver diversity into one
system
hybrid diversity
quad diversity
space diversity
wavelength diversity
24598.
24599. If the target cross section is changing, the best system for accurate tracking in
lobe switching

sequential lobing
conical switching
monopulse
24600.
24601. The multicavity klystron
is not good low-level amplifier because of noise
has a high repeller voltage to ensure a rapid transmit time
is not suitable for pulse operation
needs a long transmit time through the buncher cavity to ensure current modulation
24602.
24603. An arrangement that avoids a service interruption during periods of deep fades or
equipment failures.
service switching arrangement
protection switching arrangement
interruption switching arrangement
equipment switching arrangement
24604.
24605. A type of attenuator where attenuation is accomplished by insertion of a thin card of
resistive material through a slot in the top of a waveguide
flap attenuator
vane attenuator
slot attenuator
directional coupler
24606.
24607. After a target has been acquired, the best scanning system for tracking is
nodding
spiral
conical
helical
24608.
24609. A duplexer is used
to couple two different antennas to a transmitter without mutual interference
to allow the one antenna to be used for reception or transmission without mutual
interference
to prevent interference between two antennas when they are connected to a receiver
to increase the speed of pulses in pulsed radar
24610.
24611. Type of protection switching arrangement where each working radio channel has a
dedicated backup or spare channel
hot swap
hot backup
hot standby
hot diversity
24612.
24613. If a return echo arrives after the allocated pulse interval,
it will interfere with the operation of the transmitter

the receiver might be overloaded
it will not be received
the target will appear closer than it really is
24614.
24615. Points in the microwave system baseband signals either originate or terminate
terminator
terminal stations
terminating equipment
terminal equipment
24616.
24617. A half wavelength, closed section of a waveguide that acts as a parallel resonant circuit is
known as _____.
half-wave section
cavity resonator
LCR circuit
directional couple
24618.
24619. Decreasing the volume of a cavity causes its resonant frequency to
increase
decrease
remains the same
drop to zero
24620.
24621. The IF bandwidth of a radar receiver is inversely proportional to the
pulse width
pulse repetition frequency
pulse interval
the target will appear closer than it really is
24622.
24623. Which of the following devices are not being used in microwave power amplifier?
klystron tubes
traveling wave tubes
IMPATT
magnetron
24624.
24625. Which is not true? A high PRF will
make the returned echoes easier to distinguish from noise
make the target tracking easier with conical scanning
increase the maximum range
have no effect on the range resolution
24626.
24627. It is a unidirectional device often made up of ferrite material used in conjunction with a
channel-combining network to prevent the output from interfering with the output of another
transmitter
circulator
magic tee

isolator
rat race
24628.
24629. Which is not true about the following: Flat-topped rectangular pulses must be transmitted
in radar to
allow a good minimum range
make the returned echoes easier to distinguish from the noise
prevent frequency changes in the magnetron
allow accurate range measurements
24630.
24631. The power that leaks out of the back and sides of the transmit antenna interfering with the
signal entering with the signal entering the input of a nearby receive antenna.
ringaround
ringabout
roundabout
turnaround
24632.
24633. Which of the following is not true: The radar cross section of a target
depends on the frequency used
may be reduced by special coating of the target
depends on the aspect of a target, if this nonspherical
is equal to the actual cross-sectional area for small targets
24634.
24635. It is a general term applied to the reduction in signal strength at the input to a receiver
fading
attenuation
absorption
ghosting
24636.
24637. Indicate which of the following cannot be followed by the word “waveguide”
elliptical
flexible
coaxial
ridged
24638.
24639. If the ratio of the antenna diameter to the wavelength in a radar system is high, this will
result in (indicate the false statement)
large maximum range
good target discrimination
difficult target acquisition
increased capture area
24640.
24641.
24642. High-power TWTs are replacing what in microwave amplifiers?
MESFETs
Magnetrons

Klystrons
IMPATT diodes
24643.
24644. The most widely used microwave antenna is a
half-wave dipole
quarter-wave probe
single loop
horn
24645.
24646. Applies to propagation variables in the physical radio path which affect changes in path
loss between the transmitter at one station and its normal receiver at the other station.
ghosting
absorption
attenuation
fading
24647.
24648. If the antenna diameter in a radar system is increased by a factor of 4, the maximum
range will be increased by a factor of
square root of 2
2
4
8
24649.
24650. If the peak transmitted power in a radar system is increased by a factor of 15, the
maximum range will be increased by a factor of
2
4
8
16
24651.
24652. Varactor and step-recovery diodes are widely used in what type of circuit?
amplifier
oscillator
frequency multiplier
mixer
24653.
24654. It is defined as line loss incurred by an electromagnetic wave as it propagates in a straight
line through a vacuum with no absorption or reflection of energy from nearby objects.
IRL
FSL
RSL
Eb/No
24655.
24656. For proper operation, a magnetron must be accompanied by a
cavity resonator
strong electric field

permanent magnet
high dc voltage
24657.
24658. A police radar speed trap functions at a frequency of 1.024 GHz in direct line with your
car. The reflected energy from your car is shifted 275 Hz in frequency. Calculate the speed in
miles per hour?
60 mph
70 mph
80 mph
90 mph
24659.
24660. It is the ratio of the wideband carrier to the wideband noise power
carrier to noise ratio
signal to noise ratio
energy per bit per noise density ratio
noise figure
24661.
24662. What is the duty cycle of a radar pulse if the pulse width is 1µs, the pulse repetition rate
is 900, and the average power is 18 W?
0.09 %
0.99 %
0.90 %
1.00 %
24663.
24664. A microwave tube amplifier uses an axial magnetic field and a radial electric field. This is
the
reflex klystron
coaxial magnetron
traveling-wave magnetron
CFA
24665. Figure of merit used to indicate how much the signal-to-noise ratio deteriorates as a
signal passes through a circuit or series of circuits
noise factor
signal to noise ratio
carrier to noise ratio
dynamic range
24666.
24667. What is the peak power of a radar pulse if the pulse width is 1µs, the pulse repetition rate
is 900, and the average power is 18 W?
10 kW
15 kW
20 kW
30 kW
24668.
24669. The point where the antenna is mounted with respect to the parabolic reflector is called
the

focal point
center
locus
tangent
24670.
24671. The operating frequency of klystron and magnetrons is set by the
cavity resonators
DC supply voltage
inputsignal frequency
Number of cavities
24672.
24673. Using a small reflector to beam waves to the larger parabolic reflector is known as
focal feed
horn feed
cassegrain feed
coax feed
24674.
24675. If the noise figures and gains of each of the amplifiers in cascade is 3 dB and 10 dB
respectively. What is the total noise figure?
2.12 dB
3.24 dB
1.24 dB
4.23 dB
24676.
24677.
24678. One of the following is unlikely to be used as a pulsed device
multicavity klystron
BWO
CFA
TWT
24679.
24680. Calculate the maximum ambiguous range for a radar system with PRT equal to 400µs.
13.8 mi
43.5 mi
16.4 mi
32.8 mi
24681.
24682. When electromagnetic waves are propagated in a waveguide
they travel along the broader walls of the guide
they are reflected from the walls but do not travel along them
they travel through the dielectric without the walls
they travel along all four walls of the waveguide
24683.
24684. What is the distance in nautical miles to a target if it takes 123 µs for a radar pulse to
travel from the radar antenna to the target, back to the antenna, and be displayed on the PPI
scope?

10 nmi
5 nmi
20 nmi
15 nmi
24685.
24686. Waveguides are used mainly for microwave signals because
they depend on straight-line propagation which applies to microwaves only
losses would be too heavy at lower frequencies
there are no generators powerful enough to excite them at lower frequencies
they would be too bulky at lower frequencies
24687.
24688. Calculate the coupling of a directional coupler that has 70 mW into the main guide and
0.35 mW out the secondary guide.
13 dB
23 dB
33 dB
10 dB
24689.
24690.
24691.
24692. The wavelength of a wave in a waveguide
is greater than in free space
depends only on the waveguide dimensions and the free space wavelength
is inversely proportional to the phase velocity
is directly proportional to the group velocity
24693.
24694. A rectangular waveguide is 1 cm by 2 cm. Calculate the cutoff frequency
3.5 GHz
15 GHz
7.5 GHz
4 GHz
24695.
24696. The main difference between the operation of transmission liners and waveguides is that
the latter is not distributed, like transmission lines
the former can use stubs and quarter-wave transformers, unlike the latter
transmission lines use the principal mode of propagation, and therefore do not suffer
from low-frequency cut-off
terms such as impedance matching and standing-wave ratio cannot be applied to waveguides
24697.
24698. The useful power of the transmitter that is contained in the radiated pulses is termed as
______.
rms power
rated power
peak power
average power
24699.

24700. In radars, echoes that are produced when the reflected beam is strong enough to make a
second trip
double range echoes
double frequencies echoes
second return echoes
second time around echoes
24701.
24702. Indicate the false statement. Compared with equivalent transmission lines, 3 GHz
waveguides
are less lossy
can carry higher powers
are less bulky
have lower attenuation
24703. The range beyond which targets appear as second return echoes is called
maximum range
maximum unambiguous range
maximum usable range
any of these
24704.
24705. When a particular mode is excited in a waveguide, there appears an extra electric
component, in the direction of propagation. The resulting mode is
transverse electric
transverse magnetic
longitudinal
transverse-electromagnetic
24706.
24707. In radars, echoes that arrive after the transmission of the next pulse are called _____.
second return echoes
second time around echoes
multiple time around echoes
any of these
24708.
24709. When electromagnetic waves are reflected at an angle from a wall, their wavelength
along the wall is
the same as the free space
the same as the wavelength perpendicular to the wall
shortened because of the Doppler effect
greater than in the actual direction of propagation
24710.
24711. A radar mile is equivalent to
2000 mi
2000 m
2000 yd
2000 km
24712.
24713. As a result of reflections from a plane conducting wall, electromagnetic waves acquire an

apparent velocity of light in space
velocity of propagation
normal velocity
group velocity
phase velocity
24714.
24715.
24716. In radars, the time between pulses is called ______.
rest time
duration time
delay time
propagation time
24717.
24718. Indicate the false statement. When the free-space wavelength of a signal equals the cutoff
wavelength of the guide
the group velocity of the signal becomes zero
the phase velocity of the signal becomes infinite
the characteristic impedance of the guide becomes infinite
the wavelength within the waveguide becomes infinite
24719.
24720. In radars, the duration of the pulse is
duty cycle
pulse width
pulse amplitude
pulse cycle
24721.
24722. A signal propagated in a waveguide has a full wave electric intensity change between two
further walls, and no component of the electric field in the direction of propagation. The
mode is
TE11
TE10
TM22
TE20
24723.
24724. In radars, the number of the pulses transmitted per second is called
pulse repetition frequency
pulse repetition time
pulse repetition phase
pulse number of repetition
24725.
24726. Which of the following is incorrect? The dominant mode of propagation is preferred with
rectangular waveguides because
it leads to the smallest waveguide dimensions
the resulting impedance can be matched directly to coaxial lines
it is easier to excite than other modes
propagation of it without any spurious generation can be ensured

24727. It is a mean of employing radio waves to detect and locate objects such as aircraft, ships
and land masses.
detectors
radars
repeaters
beacons
24728.
24729. A choke flange may be used to couple two waveguides
to help the alignment of the waveguides
because it is simpler than any other join
to compensate for discontinuities at the join
to increase the bandwidth of the system
24730.
24731. The resonant frequency of a cavity may be varied by changing any of these parameters
except:
cavity volume
cavity inductance
cavity capacitance
cavity resistance
24732.
24733. In order to couple two generators to a waveguide system without coupling them to each
other, which could not be use?
rat-race
E-plane T
hybrid ring
magic T
24734.
24735. A type of tee so-named because of the side arms shunting the E field for the TE modes,
which is analogous to voltage in the transmission lines
magic tee
rat tee
series tee
shunt tee
24736.
24737. Which one of the following waveguide tuning components is not easily adjustable?
screw
stub
iris
plunger
24738.
24739. What type of waveguide is widely used?
circular
ridged
flexible
rectangular
24740.

24741. A piston attenuator is a
vane attenuator
waveguide below cutoff
mode filter
flap attenuator
24742.
24743. Waveguides act as _____.
low-pass filter
bandpass filter
high-pass filter
band-stop filter
24744.
24745. Cylindrical cavity resonators are not used with klystron because they have
a Q that is too low
a shape whose resonant frequency is too difficult to calculate
harmonically related resonant frequencies
too heavy losses
24746.
24747. In waveguides, if no component of the E field is in the direction of propagation the mode
is said to be
TE
TM
TEM
TME
24748.
24749. A directional coupler with three or more holes is sometimes used in preference to the
two-hole coupler
because it is more efficient
to increase coupling of the signal
to reduce spurious mode generation
to increase the bandwidth of the system
24750.
24751.
24752.
24753. The smallest free-space wavelength that is just unable to propagate in the waveguide
cutoff wavelength
cutoff frequency
cutoff waveguide length
cutoff phase
24754.
24755. It is the minimum frequency of waves that can propagate through the waveguide
cutoff frequency
cutoff wavelength
cutoff phase
cutoff waveguide length
24756.

24757. A common application of magnetrons is in
Radar
Satellites
Two-way radio
TV sets
24758.
24759. In waveguides, it is the velocity at which the wave changes phase
waveguide velocity
group velocity
phase velocity
total velocity
24760.
24761. The maximum power that may be handled by a ferrite component is limited by the
curie temperature
saturation magnetization
line width
gyromagnetic resonance
24762.
24763. In waveguides, it is the velocity at which the wave propagates
phase velocity
group velocity
total velocity
waveguide velocity
24764.
24765.
24766.
24767.
24768.
24769. A PIN diode is
a metal semiconductor point-contact diode
a microwave mixer diode
often used as a microwave detector
suitable for use as a microwave switch
24770.
24771. A common omnidirectional microwave antenna is the
horn
parabolic reflector
helical
bicone
24772.
24773. The output of a helical antenna is
vertically polarized
horizontally polarized
circularly polarized
linearly polarized
24774.

24775. For some applications, circular waveguides may be preferred to rectangular ones because
of
the smaller the cross section needed at any frequency
lower attenuation
freedom from spurious modes
rotation of polarization
24776.
24777. A helical antenna is made up of a coil and a
director
reflector
dipole
horn
24778.
24779. In a klystron amplifier, velocity modulation of the electron beam is produced by the
collector
catcher cavity
cathode
buncher cavity
24780.
24781.
24782.
24783.
24784. Increasing the diameter of a parabolic reflector causes which of the following:
decreased beamwidth
increased gain
none of the above
decreased beamwidth and increased gain
24785.
24786. For low attenuation, the best transmission medium is
flexible waveguide
ridged waveguide
rectangular waveguide
coaxial line
24787.
24788. Low-power Gunn diodes are replacing
Reflex klystron
TWTs
Magnetrons
Varactor diodes
24789.
24790. One of the reasons why vacuum tubes eventually fail at microwave frequencies is that
their
noise figure increases
transmit time becomes too short
shunt capacitive reactances becomes too large
series inductance reactances becomes too small

24791.
24792. A rectangular waveguide has a width of 1 inch and a height of 0.6 inch. Its cutoff
frequency is
2.54 GHz
3.0 GHz
5.9 GHz
11.8 GHz
24793.
24794. The TWT is sometimes preferred to the multicavity klystron amplifier, because the
former
is more efficient
has a greater bandwidth
has a higher number of modes
produces higher output power
24795.
24796. The most common cross section of a waveguide is a
square
circle
triangle
rectangle
24797.
24798. The cavity magnetron uses strapping to
prevent mode jumping
prevent cathode back-heating
ensure bunching
improve the phase-focusing effect
24799.
24800. Signal propagation in a waveguide is by
electrons
electric and magnetic fields
holes
air pressure
24801.
24802. The dominant mode in most waveguides is
TE 0,1
TE 1,2
TM 0,1
TM 1,1
24803.
24804. Periodic permanent-magnet focusing is used with TWTs to
allow pulsed operation
improve electron bunching
avoid the bulk of electromagnet
allow coupled-cavity operation at the highest frequencies
24805.
24806. A popular microwave mixer diode is the

Gunn
Varactor
Hot carrier
IMPATT
24807.
24808.
24809.
24810.
24811. A magnetron whose oscillating frequency is electronically adjustable over a wide range is
called a
coaxial magnetron
dither-tune magnetron
frequency-agile magnetron
VTM
24812.
24813. The main benefit of using microwave is
lower-cost equipment
sampler equipment
greater transmission distances
more spectrum space for signals
24814.
24815. Which diode is a popular microwave oscillator?
IMPATT
Gunn
Varactor
Schottly
24816.
24817. Which of the following is not a disadvantage of microwave?
higher cost equipment
line-of-sight transmission
conventional components are not usable
circuits are more difficult ro analyze
24818.
24819. Which of the following is a microwave frequency?
1.7 MHz
750 MHz
0.98 MHz
22 GHz
24820.
24821. In a TWT, the electron beam, is density-modulated by a
Permanent magnet
Modulation transformer
Helix
Cavity resonator
24822.
24823.

24824.
24825.
24826. Which of the following is not a common microwave application?
radar
mobile radio
telephone
spacecraft communications
24827.
24828. Indicate the false statement. Transit time in microwave tubes will be reduced if
the electrodes are brought closer together
a higher node current is used
multiple or coaxial loads are used
the anode voltage is made larger
24829.
24830. Coaxial cable is not widely used for long microwave transmission lines because of its
high loss
high lost
large size
excessive radiation
24831.
24832. The main advantage of the TWT over a klystron for microwave amplification is
lower cost
smaller size
higher power
wider bandwidth
24833.
24834. A magnetic field is used in the cavity magnetron to
prevent anode current in the absence of oscillations
ensure that the oscillations are pulsed
help in focusing the electron beam, thus preventing spreading
ensure that the electrons will orbit around the cathode
24835.
24836. A waveguide has a cutoff frequency of 17 GHz. Which of the signals will not be passed
by the waveguide?
15 GHz
18 GHz
22 GHz
25 GHz
24837.
24838.
24839.
24840. When the electric field in a waveguide is perpendicular to the direction of wave
propagation, the mode is said to be
vertical polarization
transverse electric
horizontal polarization

transverse magnetic
24841.
24842. The TWT is sometimes preferred to the magnetron as a radar transmitter output tube
because it is
capable of longer duty cycle
a more efficient amplifier
more broadband
less noisy
24843.
24844. A magnetic field is introduced into a waveguide by a
probe
dipole
stripline
capacitor
24845.
24846. A reflex klystron is used as a/n
amplifier
oscillator
mixer
frequency multiplier
24847.
24848. Indicate the false statement: Manganese ferrite may be used as a
circulator
isolator
garnet
phase shifter
24849.
24850. Indicate the false statement. Klystron amplifiers may use intermediate cavities to
prevent oscillations that occur in two-cavity klystron
increase the bandwidth of the device
improve the power gain
increase the efficiency of the klystron
24851.
24852.
24853. What are limits of microwaves?
1 – 25,000 GHz
1 – 50,000 GHz
1 – 75,000 GHz
1 – 100,000 GHz
24854.
24855. The following transmission lines are used for microwave frequencies, except:
waveguide
twin lead
coax
stripline
24856.

24857. How much must a waveguide be?
over a half-wave
over a quarterwave
over a wavelength
over three-fourths of a wavelength
24858.
24859. How high must a waveguide be?
over a wavelength
over a quarter wave
over a half wave
over two wavelengths
24860.
24861. What is the designation of the lowest-frequency microwave band?
V band
X band
Ku band
L band
24862.
24863. What is the designation of the highest-frequency microwave band?
R band
Ka band
V band
L band
24864.
24865.
24866.
24867.
24868.
24869. What is reduced by using choke flanges?
refraction
reflection
absorption
cancellation
24870.
24871. What is the name of the microwave transmission line that is used in printed circuits?
microstrip
coax
twin lead
twisted pair
24872.
24873. Where is the resistive load placed in a directional coupler?
front end of the primary
front end of the secondary
back end of the primary
back end of the secondary
24874.

24875. One of the following is a type of bolometer
calorimeter
thermocouple
barreter
carreter
24876.
24877. Why are bolometers not used to detect modulation?
thermal sluggishness
inefficiency
less accurate
less precise
24878.
24879. The advantage of a resonant cavity over a hairpin tank?
lesser Q
wider bandwidth
higher Q
efficiency
24880.
24881.
24882.
24883.
24884.
24885. What type of coupling is used between a waveguide and a waveguide wavemeter?
loop antenna
quarterwave antenna
hole
E probe
24886.
24887. Which microwave tube has a repeller?
TWT
Klystron
Magnetron
BWO
24888.
24889. Which microwave tube has a series of cavities?
magnetron
klystron
TWT
BWO
24890.
24891. Which microwave tube has a helix
klystron
magnetron
multicavity klystron
BWO
24892.

24893. Which microwave tube has a horseshoe magnet?
magnetron
klystron
TWT
BWA
24894.
24895. What is the advantage of a gridless klystron
power input
gain
attenuator
power output
24896.
24897.
24898.
24899.
24900.
24901. Which vacuum tube do you think oscillate at the highest frequency
Magnetron
Gunn
Klystron
BWO
24902.
24903. How would a balun be used to change 200 ohms to 50 ohms?
use a higher turns ratio
use a higher frequency
reverse it
use low frequency
24904.
24905. How could a balun change 100 ohms to 900 ohms
use 3:1 turns ratio
use 1:3 turns ratio
use 9:1 turns ratio
use 1:9 turns ratio
24906.
24907. How high a frequency can transistor generate?
above 10 GHz
above 5 GHz
above 2 GHz
above 7.8 GHz
24908.
24909. What is the microwave application of a varactor?
mixer
frequency multiplier
demodulator
demultiplexer
24910.

24911. What diode does better than varactor in microwave frequencies?
step recovery
tunnel
PIN
Gunn
24912.
24913.
24914.
24915.
24916.
24917. The following diodes can generate microwave AC except:
Tunnel
LSA
IMPATT
Magnetron
24918.
24919. For what are PIN diodes used in microwave?
mixers
modulators
oscillators
amplifier
24920.
24921. What is the other name for LSA diodes?
negative resistance
bulk-effect
tunneling effect
time-space
24922.
24923. What is the advantage of LSA over a Gunn Diode?
more efficient
higher power
less noise
higher frequency
24924.
24925. What is wrong with the term Gunn Diode?
not a gun
not a semiconductor
not a diode
should be spelled with single “n”
24926.
24927. What is important property do ferrites have which is used as a switch?
faraday rotation
resonance absorption
magnetic properties
high curie temperature
24928.

24929.
24930.
24931.
24932.
24933. Which is used in circulators?
resonance absorption
magnetic properties
ion resonance
faraday rotation
24934.
24935. What is the advantage of using a circulator with two transmitter and two receivers?
many antennas
less interference
easy coupling
one antenna only
24936.
24937. To what must the fourth port be connected in a tunnel diode amplifier?
resistor
inductor
capacitor
impedance
24938.
24939. To what must the third port be connected in a multiplexer circulator
reflecting short circuit
absorbing short circuit
reflecting open circuit
absorbing open circuit
24940.
24941. What does radar mean?
radio detection and range
radio direction and radiation
radio direction and range
range direction radiation
24942.
24943. In what distance unit are marine radars calibrated?
statute miles
kilometers
nautical miles
feet
24944.
24945.
24946.
24947.
24948.
24949. What time unit is the equivalent of a radar mile?
12.3 microseconds

6.8 microseconds
4.5 microseconds
7.1 microseconds
24950.
24951. In what frequency band does marine radar operate?
9.5 GHz S band
3 GHz X band
9.5 GHz Ku band
3 GHz S band
24952.
24953. To what two circuits would a radar timer circuit feed signals?
modulator and mixer
amplifier and circulator
modulator and circulator
amplifier and modulator
24954.
24955. What is the target display on a CRT called?
crosshair
blip
center spot
round
24956.
24957. What is the main bang on a PPI radar set?
blip
center spot
bearing
round
24958.
24959. What is the ability to separate adjacent equidistant targets called?
bearing resolution
narrow bandwidth
high frequency
shorter wavelength
24960.
24961.
24962.
24963.
24964.
24965. What is the approximate rotational rate of a radar antenna?
20 rpm
5 rpm
25 rpm
10 rpm
24966.
24967. How is radar CRTs differ from TV?
square

round
rectangular
trapezoidal
24968.
24969. What circuits make up the radar transmitter?
multivibrator
trapezoidal oscillator
sinewave generator
blocking oscillator
24970.
24971. What type of oscillator determines the PRR?
blocking
pulse
square
blocking or pulse
24972.
24973. What other circuit might be used as an oscillator that determines the PRR?
trapezoidal generator
unbalanced multivibrator
bistablemultivibrator
sinewave generator
24974.
24975. Why are hydrogen-gas thyratrons used in radar?
fast-ionize
cheaper
accurate
efficient
24976.
24977.
24978.
24979.
24980.
24981. What is the other name for a pulse-forming network in radars?
tuned circuit
oscillators
delay line
capacitive circuits
24982.
24983. What determines the PRR in odd-time radar sets?
tuned circuit frequency
oscillator frequency
spark gap speed
MOPA transmitter time
24984.
24985. What is used to carry RF energy from magnetron to antenna in a radar set?
helix

parallel wireline
coax
waveguide
24986.
24987. What is the method of illuminating a parabolic reflector with RF?
horn
cassegrain
helix
coax
24988.
24989. How would a radar reflector be parabolic-shaped
circularly
vertically
horizontally
none of these
24990.
24991. In what way are radar emissions similar to microwave ovens?
can transmit
can receive
can cook
can transceiver
24992.
24993.
24994.
24995.
24996.
24997. To what tube is a dc keep-alive voltage applied?
Oscillator
Transmit-Receive Mixer
Circulator
Isolator
24998.
24999. In radar, if the mixer diode burns out, what are replaced?
tube
mixer
antenna
diode
25000.
25001. What is the cavity between magnetron and mixer cavity called?
ATR
TR
Transmit
Receive
25002.
25003. Radar receivers use what Ifs
20 MHz and lower

10 MHz and higher
30 MHz or higher
10 MHz and lower
25004.
25005. What kind of local oscillators does a radar receiver use?
klystron
magnetron
LSA
TWT
25006.
25007. What solid-state types might be used as a radar receiver?
Gunn diode
Tunnel diode
Hot carrier diode
Step recovery diode
25008.
25009.
25010.
25011.
25012.
25013. What does an ATR tube aid?
transmitting
receiving
both transmitting and receiving
neither transmitting and receiving
25014.
25015. To what is the AFC voltage applied in a klystron?
cathode
grid
plate
any of these
25016.
25017. Sea return is the control that desentisizes a radar receiver for _____
5 – 10 microseconds
15 – 20 microseconds
10 – 15 microseconds
20 – 25 microseconds
25018.
25019. In radars, how is blooming prevented?
limit modulation
video signal
limit the carrier signal
limit the audio signal
25020.
25021. How is brilliance controlled in radars?
audio gain

IF gain
RF gain
video gain
25022.
25023. How is sensitivity limited in radars?
RF gain
video gain
audio gain
IF gain
25024.
25025.
25026.
25027.
25028.
25029. How much intensifying pulse is used in radars?
Just enough to produce light flicker on screen
should be high to produce light flicker on screen
should be low to produce light flicker on screen
any amount of intensifying pulse will do
25030.
25031. If echo signals are developed as negative pulses, to what part of the CRT would they be
fed in radar?
anode
grid
cathode
2nd grid
25032.
25033. What starts the range-marker circuit ringing in radars?
intensifying pulse
IF gain
AC signal
Carrier signal
25034.
25035. Why is a selsyn pair not too successful for radar antenna synchronization?
constant lead angle
variable lag angle
constant lag angle
variable lead angle
25036.
25037. What is fed to the rotor of a selsyn motor?
power-line AC
DC source
A pulsating DC
None
25038.
25039. What is fed to the rotor selsyn generator?

none
power-line AC
DC source
A pulsating DC
25040.
25041.
25042.
25043. What is fed to a control transformer rotor?
A pulsating DC
power-line AC
DC source
none
25044.
25045. What is used to indicate the bow of the ship on the CRT?
tail flash
body flash
heading flash
none
25046.
25047. When is an echo box used on ships?
testing only
direction finding
auto alarm
ship detection
25048.
25049. What qualification must a person have before he is eligible to make repairs to a radar set?
NTC endorsement
repair license
repair endorsement
radar endorsement
25050.
25051. What is the advantage of using Doppler radar?
shows only moving target
shows stationary target
shows both moving and stationary target
produce blips with stationary targets
25052.
25053. How would Doppler radar give speed indications?
adjust output burst
correct RF carrier output
switch amplitude detector
calibrate discriminator output
25054.
25055.
25056.
25057.

25058.
25059. What is another application of Doppler radar?
distance between radar and stationary target
ground speed indicator
ground missile indicator
enemy base station
25060.
25061. Why are signal nulls used in Radio Direction Finders work?
sharper than maximums
sharper than minimums
duller than maximums
duller than minimums
25062.
25063. How many are signal nulls in one loop rotation Radio Direction Finders?
3
4
5
2
25064.
25065. Under what conditions do the horizontal portions of a loop pick up difference currents in
RDF?
ground waves
sky waves
space waves
direct waves
25066.
25067. The method of balancing a loop used in RDF?
Capacitor to ground
Capacitor to sense antenna
Sense antenna to one side of loop
Any of these
25068.
25069. For what are unidirectional readings used in loops for RDF?
resolve a 180 degrees ambiguity
resolve a 90 degrees ambiguity
resolve a 360 degrees ambiguity
resolve a 270 degrees ambiguity
25070.
25071.
25072.
25073.
25074. What kind of antenna is a sense antenna used in RDF?
circular
vertical
horizontal
any of these

25075.
25076. In RDF, what happens to a radio wave path as it moves outward across a coastline as less
than 90 degrees?
bends away from the shore
travels along the shore
bends towards shore
travels across the shore
25077.
25078. What is the result of antenna effect in RDF?
rotated 90 degrees
nulls shift
decreases land effect
coastline refraction
25079.
25080. What is the result of re-radiation of signals in RDF?
great circle error
non-opposite minimums
polarization errors
nulls shifted
25081.
25082. What causes night effect in direction finding?
ground plus space wave
sky plus space wave
ground plus sky waves
ground wave alone
25083.
25084. At what time of the day is direction finder bearings least accurate
sunset
sunrise
mid-day
sunset and sunrise
25085.
25086.
25087.
25088.
25089. At what angles are quadrantal errors maximum in direction finding
45 degrees
90 degrees
180 degrees
270 degrees
25090.
25091. How are quadrantal errors corrected?
330 degrees
360 degrees
315 degrees
215 degrees

25092.
25093. How is it that none of the 120-550 kHz ADF circuits are tuned to the desired station?
narrowband amplifiers
broadband amplifiers
IF amplifiers
Mixers
25094.
25095. What is the only hand-tuned circuit in the ADF?
3125-kHz signal local oscillator
4125-kHz signal local oscillator
2182-kHz signal local oscillator
2230-kHz signal local oscillator
25096.
25097. What forms the error signal that actuates the ADF servo-motor?
75-Hz carrier
114-Hz carrier
114-Hz sideband
75-Hz sideband
25098.
25099. Which ADF antenna is used for manual operation?
parabolic antenna
loop antenna
half-wave dipole
helical antenna
25100.
25101.
25102.
25103.
25104.
25105. Which ADF antenna is used for simple receive operation?
loop antenna
sense antenna
quarterwave antenna
parabolic antenna
25106.
25107. What is heard by earphones in the ADF?
3 kHz beat
1 kHz beat
2 kHz beat
5 kHz beat
25108.
25109. If two bearing are determined from a radio beacon or station over a period of a few
minutes, what else must be known to determine the ship’s position?
speed
elapses time
ship’s course

any of these
25110.
25111. What important point regarding-loop RDF system maintenance?
insulation at top of loop
clean moving contacts
oil bearing of loop
any of these
25112.

25113.
25114.
25115.
25116.
25117.
25118.
25119.
25120.
25121.
25122.
25123.

25124. MULTIPLE CHOICE QUESTIONS IN

25125. TELEPHONY AND
FACSIMILE
25126.

Electronics Systems and Technologies
25127. By
25128.

Melvin C. Arceo

25129.
25130.
25131.
25132.
25133.
25134.
25135.
25136.

25137. ENCODED BY:

25138. RIVERA, Billy Joe S.

25139.

1. The simplest and most straightforward form of telephone service is

called
25140.
25141.
Public switch telephone network
25142.
Mobile telephone switching office
25143.
Plain and old telephone service
25144.
Central office service
25145.
25146.
2. _______ are local telephone switches equipped with SS7-compatible software
and terminating signal links
25147.
25148.
A. switching points
25149.
B. service points
25150.
C. point codes
25151.
D. service switching points
25152.
25153.
3. A PABX is normally connected to the central office via an interface device
called
25154.
25155.
A. branch exchange unit
25156.
B. subscriber loop unit
25157.
C. foreign exchange unit
25158.
D. local exchange unit
25159.
25160.
4. The most widely used fax standard is
25161.
25162.
A. group 1
25163.
B. group 2
25164.
C. group 3
25165.
D. group 4
25166.
25167.
5. The modern Touch-tone telephone is called
25168.
25169.
A. 600-type telephone set
25170.
B. 2500-type telephone set
25171.
C. 2800-type telephone set
25172.
D. 1500-type telephone set
25173.
25174.
6. Signals that provides call status information, such as busy or ringback signals
25175.
25176.
A. supervising
25177.
B. hybriding
25178.
C. controlling
25179.
D. ringing

25180.
25181.
7. A signal sent back to the calling party at the same time the ringing signal is sent
to the called party
25182.
25183.
A. busy signal
25184.
B. ringing signal
25185.
C. ringback signal
25186.
D. dial tone
25187.
25188.
8. It is comprised of two or more facilities, interconnected in tandem, to provide a
transmission path between a source and a destination
25189.
25190.
A. telephone line
25191.
B. telephone set
25192.
C. telephone circuit
25193.
D. telephone trunk
25194.
25195.
9. The drum diameter of a facsimile machine is 90.2 mm and the scanning pitch is
0.2 mm per scan. Find the index of cooperation according to CCITT
25196.
25197.
A. 451
25198.
B. 2.22 x 10^-3
25199.
C. 1417
25200.
D. 144
25201.
25202.
10. It is the ratio in dB of the power of a signal at that point to the power the same
signal would be 0-dBm at any point in the transmission system
25203.
25204.
A. data level
25205.
B. baseband level
25206.
C. voice level
25207.
D. transmission level
25208.
25209.
11. It is an indirect method of evaluating the phase delay characteristics of the
circuit
25210.
25211.
A. phase delay distortion
25212.
B. envelope delay distortion
25213.
C. non-linear distortion
25214.
D. linear distortion
25215.
25216.
12. It is characterized by high-amplitude peaks of short duration having an
approximately flat frequency response
25217.
25218.
A. crosstalk
25219.
B. interference

25220.
C. impulse noise
25221.
D. drop out
25222.
25223.
13. It is the presence of one or more continuous, unwanted tones within the
message channels, the tones are often caused by crosstalk or cross modulation between
adjacent channels in a transmission system due to system nonlinearities.
25224.
25225.
A. multiple-frequency interference
25226.
B. single-frequency interference
25227.
C. co-channel interference
25228.
D. desensitizing
25229.
25230.
14. That portion of the local loop that is strung between the poles
25231.
25232.
A. aerial
25233.
B. distribution cable
25234.
C. feeder cable
25235.
D. twisted-pair
25236.
25237.
15. It is the primary cause of attenuation and phase distortion on a telephone
circuit
25238.
25239.
A. local line
25240.
B. local loop
25241.
C. subscriber loop
25242.
D. any of these
25243.
25244.
16. It is simply the frequency response of a transmission medium referenced to a
1004-Hz test tone
25245.
25246.
A. attenuation distortion
25247.
B. differential gain
25248.
C. 1004-Hz deviation
25249.
D. any of these
25250.
25251.
17. The time delay measured in angular units, such as degrees or radians is called
__________
25252.
25253.
A. propagation time
25254.
B. phase delay
25255.
C. holding time
25256.
D. system delay time
25257.
25258.
18. It is a communications term that indicates the presence of a signal power
comparable to the power of an actual message transmission
25259.

25260.
A. dynamic range
25261.
B. loaded
25262.
C. node
25263.
D. reference
25264.
25265.
19. It is any device used to originate and terminate calls and to transmit and
receive signals into and out of the telephone network
25266.
25267.
A. instrument
25268.
B. station equipment
25269.
C. station
25270.
D. any of these
25271.
25272.
20. Exchanges connected directly to the local loops are called ______________
25273.
25274.
A. central office
25275.
B. local exchange
25276.
C. exchange offices
25277.
D. any of these
25278.
25279.
21. It provides functionality of communicating with the voice switch by creating
the packets or signal units necessary for transmission over the SS7 network
25280.
25281.
A. switching points
25282.
B. service points
25283.
C. point codes
25284.
D. service switching points
25285.
25286.
22. In a 4-wire telephone set connection, (used to connect telephone set to central
office switching) the green coded wire is used _______________
25287.
25288.
A. as ground wire
25289.
B. to transmit the signal
25290.
C. to receive the signal from the far end
25291.
D. as a spare or for special purpose applications
25292.
25293.
23. A technique where the called subscriber is served by any other central office,
the switching equipment will have to transfer the digit dialed to the called switching
equipment.
25294.
25295.
A. loop signaling
25296.
B. step-by-step switching
25297.
C. interoffice calling
25298.
D. duplex signaling
25299.

25300.
24. Electromagnetic coupling between two or more physically interconnected
transmission media is what type of crosstalk?
25301.
25302.
A. coupling crosstalk
25303.
B. transmission crosstalk
25304.
C. linear crosstalk
25305.
D. non-linear crosstalk
25306.
25. The number of dedicated lines used to interconnect 100 parties
25307.
25308.
A. 99 lines
25309.
B. 1250 lines
25310.
C. 4950 lines
25311.
D. 3450 lines
25312.
25313.
26. Class of switching office which is the local exchange where the subscriber
loops terminated and received dial tone.
25314.
25315.
A. Class 5
25316.
B. Class 4C
25317.
C. Class 3
25318.
D. Class 1
25319.
25320.
27. The maximum intelligibility of voice frequency is between
25321.
25322.
A. 2000 and 3000 Hz
25323.
B. 1000 and 3000 Hz
25324.
C. 2500 and 4000 Hz
25325.
D. 1000 and 2500 Hz
25326.
25327.
28. It is the state of the telephone when it is idle.
25328.
25329.
A. on-hook
25330.
B. off-hook
25331.
C. semi-hook
25332.
D. hook-in
25333.
25334.
29. Type of loop signaling which is widely used in new switching systems to
supervise trunks between two central offices.
25335.
25336.
A. battery and ground pulsing
25337.
B. reverse battery signaling
25338.
C. loop pulsing
25339.
D. duplex signaling
25340.
25341.
30. Printed documents to be transmitted by fax are converted into a baseband
electrical signal by the process of

25342.
25343.
A. reflection
25344.
B. scanning
25345.
C. modulation
25346.
D. light variations
25347.
25348.
31. The transmission speed of group 4 fax is
25349.
A. 4800 baud
25350.
B. 9600 baud
25351.
C. 56 kbps
25352.
D. 192 kbps
25353.
25354.
32. It is a distortion formed if SSB is used where the information bandwidth is
greater than half of the carrier frequency.
25355.
25356.
A. near-far effect
25357.
B. hauffman effect
25358.
C. kendall effect
25359.
D. herringbone effect
25360.
25361.
33. It is simply an unshielded twisted pair transmission line consisting of two
insulated conductors twisted together.
25362.
25363.
A. local loop
25364.
B. local line
25365.
C. subscriber loop
25366.
D. any of these
25367.
25368.
34. It is an audible signal comprised of two frequencies: 350 Hz and 440 Hz
25369.
25370.
A. dial tone
25371.
B. ringback signal
25372.
C. busy tone
25373.
D. call waiting tone
25374.
25375.
35. It enables the destination station of a telephone call to display the name of the
telephone number of the calling party before the telephone is answered.
25376.
25377.
A. conference call
25378.
B. call wait
25379.
C. call forwarding
25380.
D. caller id
25381.
25382.
36. The largest cable used in a local loop, usually 3600 pair of copper wires
placed underground or in conduit.
25383.

25384.
A. feeder cable
25385.
B. distribution cable
25386.
C. drop wire
25387.
D. drop-wire cross-connect cables
25388.
25389.
37. A weighting technique that assumes a perfect receiver only, therefore its
weighting curve corresponds to the frequency response of the ear only.
25390.
A. relative noise weighting
25391.
B. above relative noise weighting
25392.
C. C-message noise weighting
25393.
D. psophometric noise weighting
25394.
25395.
38. The difference between the absolute delays of all frequencies.
25396.
25397.
A. relative phase delay
25398.
B. phase delay distortion
25399.
C. absolute phase delay
25400.
D. phase distortion
25401.
25402.
39. A special type of line conditioning that sets the minimum requirements for
signal-to-noise ratio a nonlinear distortion.
25403.
25404.
A. A-type line conditioning
25405.
B. B-type line conditioning
25406.
C. C-type line conditioning
25407.
D. D-type line conditioning
25408.
25409.
40. It is a form of incidental phase modulation – a continuous uncontrolled
variations in the zero crossings of a signal.
25410.
25411.
A. crosstalk
25412.
B. co-channel interference
25413.
C. phase jitter
25414.
D. spikes
25415.
25416.
41. A type of crosstalk which is a direct result of nonlinear amplification in analog
communications system
25417.
25418.
A. linear crosstalk
25419.
B. transmittance crosstalk
25420.
C. nonlinear crosstalk
25421.
D. coupling crosstalk
25422.
25423.
42. The operator of the telephone instrument
25424.
25425.
A. subscriber

25426.
B. destination
25427.
C. source
25428.
D. terminal
25429.
25430.
43. It is a system of sensors, switches and other electronic and electrical devices
that allow subscriber to give instructions directly to the switch without having to go
through the operator.
25431.
25432.
A. manual switching system
25433.
B. automated switching system
25434.
C. common switching system
25435.
D. crossbar switching system
25436.
25437.
44. Toll offices are connected to other toll offices with _____________
25438.
25439.
A. intertoll trunks
25440.
B. intratoll trunks
25441.
C. interoffice trunks
25442.
D. intraoffice trunks
25443.
25444.
45. The highest ranking office in the DDD network in term of size of the
geographical area served and the trunk options available.
25445.
25446.
A. End office
25447.
B. Sectional center
25448.
C. Regional center
25449.
D. Toll center
25450.
25451.
46. He invented the automatic line selector, which led to the automatic telephone
system.
25452.
25453.
A. Alexander Bain
25454.
B. Alexander Graham Bell
25455.
C. Thomas Edison
25456.
D. Almon Strowger
25457.
25458.
47. It allows customers to change to a different service and still keep the same
phone number
25459.
25460.
A. changing
25461.
B. porting
25462.
C. transporting
25463.
D. portability
25464.
25465.
48. By definition, speech power is equal to v.u. reading minus ___________
25466.

25467.
A. 1.8 dB
25468.
B. 4 dB
25469.
C. 1.4 dB
25470.
D. 3 dB
25471.
25472.
49. When the telephone set is in the ____________ state, a direct current from the
central office (CO) flows through the transmitter and receiver of the handset.
25473.
25474.
A. on-hook
25475.
B. off-hook
25476.
C. semi-hook
25477.
D. hook-in
25478.
25479.
50. Type of loop signaling which involves opening and closing the loop to dial to
or through the central office.
25480.
25481.
A. ear and mouth
25482.
B. duplex
25483.
C. loop pulsing
25484.
D. interoffice calling
25485.
25486.
51. When the image at the receiving end of a facsimile transmission is elongated
vertically,
25487.
25488.
A. the transmitter IOC is less than the receiver IOC
25489.
B. the transmitter IOC is greater than the receiver IOC
25490.
C. the transmitter IOC is equal to the receiver IOC
25491.
D. the IOC is not a factor
25492.
25493.
52. In FM fax, the frequencies for black and white are
25494.
25495.
A. 1500 and 2300 Hz
25496.
B. 2200 and 1500 Hz
25497.
C. 1300 and 2400 Hz
25498.
D. 1070 and 1270 Hz
25499.
25500.
53. It is a measure of the faithful reproduction of scanned prints in a facsimile
communications.
25501.
25502.
A. fidelity
25503.
B. contrast
25504.
C. legibility
25505.
D. chroma
25506.
25507.
54. The feedback signals that help prevent the speaker from talking too loudly.
25508.

25509.
A. busy tone
25510.
B. ringback tone
25511.
C. dial tone
25512.
D. sidetone
25513.
25514.
55. It is the exchange of signaling messages between switching machines
25515.
25516.
A. loop signaling
25517.
B. station signaling
25518.
C. interoffice signaling
25519.
D. pulse signaling
25520.
25521.
56. A signal sent from the switching machine back to the calling station whenever
the system cannot complete call because of equipment unavailability.
25522.
25523.
A. busy tone
25524.
B. call waiting tone
25525.
C. fax tone
25526.
D. congestion tone
25527.
25528.
57. The final length of cable pair that terminates at the SNI
25529.
25530.
A. aerial
25531.
B. drop wire
25532.
C. distribution cable
25533.
D. cross-connect cables
25534.
25535.
58. It is the difference in circuit gain experienced at a particular frequency with
respect to the circuit gain of a reference frequency.
25536.
25537.
A. dynamic range
25538.
B. absorption distortion
25539.
C. attenuation distortion
25540.
D. selective fading
25541.
25542.
59. In telephone systems, a special type of line conditioning that pertains to line
impairments for which compensation can be made with filters and equalizers.
25543.
25544.
A. A-line conditioning
25545.
B. B-line conditioning
25546.
C. C-line conditioning
25547.
D. D-line conditioning
25548.
25549.
60. An envelope delay distortion test on a basic telephone channel indicated that
an 1800-Hz carrier experienced the minimum absolute delay of 400 us. The maximum

envelope delay for a basic telephone channel is 1750 us within the frequency range 800
Hz to 2600 Hz. What is the maximum envelope delay?
25550.
25551.
A. 2150 microsec
25552.
B. 2550 microsec
25553.
C. 3000 microsec
25554.
D. 3400 microsec
25555.
25556.
61. In SS7 signaling points, codes that are carried in signaling messages
exchanged between signaling points to identify the source and destination of each
message
25557.
25558.
A. signaling points
25559.
B. service points
25560.
C. switching points
25561.
D. point codes
25562.
25563.
62. Stage of the step-by-step switching system that is composed of switches to
complete the connection to the called subscriber.
25564.
25565.
A. line equipment
25566.
B. switch train
25567.
C. connectors
25568.
D. switching network
25569.
25570.
63. ____________ is the switching system that is a branch of the local central
office.
25571.
25572.
A. local exchange
25573.
B. branch exchange
25574.
C. subscriber loop
25575.
D. line
25576.
25577.
64. Most fax printers are of which type?
25578.
25579.
A. Impact
25580.
B. Thermal
25581.
C. Electrosensitive
25582.
D. Laser xerographic
25583.
25584.
65. Aside from tip and ring used in local loops the third wire when used is called
__________.
25585.
25586.
A. reserve
25587.
B. sleeve
25588.
C. ground

25589.
D. none of these
25590.
25591.
66. Acknowledgement and status signals that ensure the process necessary to set
up and terminate a telephone call are completed in an orderly and timely manner,
25592.
25593.
A. call progress tones and signals
25594.
B. call waiting tones and signals
25595.
C. incoming call tones and signals
25596.
D. call termination tones and signals
25597.
25598.
67. POCSAG stands for
25599.
25600.
A. Post Office Code Standardization Advisory Group
25601.
B. Post Office Code System Advisory Group
25602.
C. Paging Operation Code Standardization Advisory Group
25603.
D. Paging Operation Code System Advisory Group
25604.
68. The location where individual cable pairs within a distribution cable are
separated and extended to the subscriber’s location on a drop wire
25605.
25606.
A. feeder cable and distribution cable
25607.
B. drop wire and aerial cable
25608.
C. distribution cable and drop-wire cross-connect cables
25609.
D. distribution cable and aerial cable
25610.
25611.
69. In telephone systems, a special type of line conditioning that specifies the
maximum limit for attenuation distortion and envelope delay distortion.
25612.
25613.
A. A-line conditioning
25614.
B. B-line conditioning
25615.
C. C-line conditioning
25616.
D. D-line conditioning
25617.
25618.
70. A the receiver, the phase difference at the different carrier frequencies is
called _________.
25619.
25620.
A. envelope delay distortion
25621.
B. phase delay
25622.
C. envelope delay
25623.
D. propagation time
25624.
25625.
71. It is a sudden, random changes in the phase of the signal. They are classified
as temporary variations in the phase of the signal lasting longer than 4 ms.
25626.
25627.
A. phase hits
25628.
B. phase jitter
25629.
C. interference

25630.
D. distortion
25631.
25632.
72. Circuits that are designed and configured for their use only and often referred
to as private circuits or dedicated circuits.
25633.
25634.
A. switched circuits
25635.
B. leased circuits
25636.
C. virtual circuits
25637.
D. switched virtual circuits
25638.
25639.
73. It is a programmable matrix that allows circuits to be connected to one
another.
25640.
25641.
A. circuit switch
25642.
B. tap switch
25643.
C. equipment switch
25644.
D. cross switch
25645.
25646.
74. Interstate long distance telephone calls require a small telephone office called
_________.
25647.
25648.
A. sectional office
25649.
B. regional office
25650.
C. toll office
25651.
D. end office
25652.
25653.
75. A call that cannot be completed because the necessary trunk circuits or
switching paths are not available.
25654.
25655.
A. blocking
25656.
B. holding
25657.
C. storing
25658.
D. none of these
25659.
25660.
76. A mandate that requires all telephone companies to support the porting of
telephone number.
25661.
25662.
A. national number portability
25663.
B. regional number portability
25664.
C. local number portability
25665.
D. sectional number portability
25666.
25667.
77. The connection between the telephone and the central office’s switching
equipment.
25668.
25669.
A. subscriber loop

25670.
B. relay circuits
25671.
C. line sensors
25672.
D. supervisory relay
25673.
25674.
78. An exact reproduction of a document or picture provided at the receiving end.
25675.
25676.
A. television
25677.
B. telecommunication
25678.
C. facsimile transmission
25679.
D. mobile communication
25680.
25681.
79. What type of graphics are commonly transmitted by radio fax?
25682.
25683.
A. Newspaper text
25684.
B. Architectural drawings
25685.
C. Cable movies
25686.
D. Satellite weather photos
25687.
25688.
80. It is comprised of a transmitter, receiver, an electrical network for
equalization, associated circuitry to control sidetone levels and to regulate signal power
and necessary signaling circuitry.
25689.
25690.
A. telephone
25691.
B. television
25692.
C. facsimile
25693.
D. computer
25694.
25695.
81. Early paging system uses what modulation technique?
25696.
25697.
A. pulse modulation
25698.
B. amplitude modulation
25699.
C. phase modulation
25700.
D. frequency modulation
25701.
25702.
82. A device that serves as a demarcation point between local telephone company
responsibility and subscriber responsibility for telephone service.
25703.
25704.
A. standard network interface
25705.
B. subscriber line interface card
25706.
C. system network architecture
25707.
D. network interface card
25708.
25709.
83. It is the actual time required for a particular frequency to propagate from a
source to a destination through a communications channel.
25710.
25711.
A. relative phase delay

25712.
B. phase delay distortion
25713.
C. absolute phase delay
25714.
D. phase distortion
25715.
25716.
84. It is a sudden, random change in the gain of the circuit resulting in a
temporary change in the signal level.
25717.
25718.
A. spikes
25719.
B. gain hits
25720.
C. jitter
25721.
D. echo
25722.
25723.
85. A typical echo suppressor suppresses the returned echo by how much?
25724.
25725.
A. 10 dB
25726.
B. 30 dB
25727.
C. 45 dB
25728.
D. 60 dB
25729.
25730.
86. In telephony, functions that supply and interpret control and supervisory
signals needed to perform the operation
25731.
25732.
A. calling functions
25733.
B. maintenance functions
25734.
C. signaling functions
25735.
D. transmission functions
25736.
25737.
87. It is a central location where subscribers are interconnected, either temporarily
or on a permanent basis.
25738.
25739.
A. central offices
25740.
B. exchange offices
25741.
C. exchanges
25742.
D. any of these
25743.
25744.
88. It is simply a path between two subscribers and is comprised of one or more
switches, two local loops or possibly one or more trunk circuits.
25745.
25746.
A. way
25747.
B. route
25748.
C. path
25749.
D. mode
25750.
25751.
89. It defines the procedures and protocols necessary to exchange information
over the PSTN using a separate digital signaling network to provide wireless and wireline
telephone call setup, routing and control.

25752.
25753.
A. any of these
25754.
B. common channel signaling system no. 7
25755.
C. SS7
25756.
D. C7
25757.
90. In a 4-wire telephone set connection, (used to connect telephone set to central office
switching) the red coded wire is used __________.
25758.
25759.
A. as ground wire
25760.
B. to transmit the signal
25761.
C. to receive the signal from the far end
25762.
D. as a spare or for special purpose applications
25763.
25764.
91. The connection between two central offices
25765.
25766.
A. line
25767.
B. trunk
25768.
C. loop
25769.
D. signaling
25770.
25771.
92. In facsimile, the length of time required to transmit a document
25772.
A. propagation time
25773.
B. transmission rate
25774.
C. holding time
25775.
D. transmission time
25776.
25777.
93. It is a combination of passive components that are used to regulate the
amplitude and frequency response of the voice signals.
25778.
25779.
A. equalizer circuit
25780.
B. balanced transformer
25781.
C. balanced modulator
25782.
D. hybrid network
25783.
25784.
94. A signal that is sent from the switching machine back to the calling station
whenever the called telephone number is off-hook.
25785.
25786.
A. dial tone signal
25787.
B. ringback signal
25788.
C. busy signal
25789.
D. off-hook signal
25790.
25791.
95. A smaller version of the feeder cable containing less wire pairs.
25792.
25793.
A. aerial

25794.
B. drop wire
25795.
C. feeder cable
25796.
D. distribution cable
25797.
25798.
96. It is a parameter equivalent to TLP except that it is used as a reference for data
transmission.
25799.
25800.
A. transmission level point
25801.
B. data level point
25802.
C. voice level point
25803.
D. baseband transmission point
25804.
25805.
97. He developed the first instrument that transmitted music over a wire
25806.
25807.
A. Philipp Reis
25808.
B. Antonio Meucci
25809.
C. Thomas Edison
25810.
D. Almon Strowger
25811.
25812.
98. It is used to convert two-wire circuits to four-wire circuits which is similar to
hybrid coil found in standard telephone sets.
25813.
25814.
A. balanced transformer
25815.
B. hybrid circuits
25816.
C. balanced modulator
25817.
D. hybrid transformers
25818.
25819.
99. A switchboard with four digits can accommodate how many telephone
numbers?
25820.
25821.
A. 1,000
25822.
B. 10,000
25823.
C. 100,000
25824.
D. 9999
25825.
25826.
100. The trunk circuits that are terminated in tandem switches are called
25827.
25828.
A. tie trunks
25829.
B. tandem trunks
25830.
C. office trunks
25831.
D. exchange trunks
25832.
25833.
101. The class of switching office that provides service to small groups of class 4
offices within a small area of state.
25834.
25835.
A. Class 1

25836.
B. Class 4
25837.
C. Class 2
25838.
D. Class 3
25839.
25840.
102. A device used to measure speech volume
25841.
25842.
A. volume unit meter
25843.
B. volume milliammeter
25844.
C. volume pulse meter
25845.
D. volume intensity meter
25846.
25847.
103. The communications between two or three central offices is called
25848.
25849.
A. interoffice link
25850.
B. trunk
25851.
C. interoffice calling
25852.
D. loop
25853.
25854.
104. In telephony, the -48V dc voltage was used rather than ac voltages because
25855.
25856.
A. to prevent power supply hum
25857.
B. to allow service to continue in the event of power outage
25858.
C. because people are afraid of ac
25859.
D. all of these
25860.
105. Category of signaling message that indicates a request of service, such as
going off-hook or ringing in the destination telephone
25861.
25862.
A. dial tone
25863.
B. signaling
25864.
C. supervising
25865.
D. alerting
25866.
25867.
106. Occurs in coherent SSBSC systems, such as those using frequency division
multiplexing when the received carrier is not reinserted with the exact phase relationship
to the received signal as the transmit carrier possessed.
25868.
25869.
A. phase delay distortion
25870.
B. phase jitter distortion
25871.
C. phase intercept distortion
25872.
D. all of these
25873.
25874.
107. It is simply the dedicated cable facility used to connect an instrument at a
subscriber’s station to the closest telephone office.
25875.
25876.
A. subscriber lines
25877.
B. local loops

25878.
C. subscriber loops
25879.
D. any of these
25880.
25881.
108. A telephone call completed within a single local exchange is called
25882.
25883.
A. intraoffice call
25884.
B. intraexchange call
25885.
C. intraswitch call
25886.
D. any of these
25887.
25888.
109. Type of Class 4 toll center usually had only outward operator service or
perhaps no operator service at all.
25889.
25890.
A. Class 2
25891.
B. Class 4P
25892.
C. Class 1
25893.
D. Class 3
25894.
25895.
110. In a 4-wire telephone set connection, (used to connect telephone set to office
central switching) the yellow coded wire is used _______________.
25896.
25897.
A. as ground wire
25898.
B. to transmit the signal
25899.
C. to receive the signal from the far end
25900.
D. as a spare or for special purpose applications
25901.
25902.
111. When the image at the receiving end of a facsimile transmission us elongated
horizontally,
25903.
25904.
A. the transmitter IOC is less than the receiver IOC
25905.
B. the transmitter IOC is greater than the receiver IOC
25906.
C. the transmitter IOC is equal to the receiver IOC
25907.
D. the IOC is not a factor
25908.
25909.
112. It is a special balanced transformer used to convert a two-wire circuit into a
four-wire circuit and vice-versa.
25910.
25911.
A. equalizer circuit
25912.
B. balanced transformer
25913.
C. balanced modulator
25914.
D. hybrid network
25915.
25916.
113. It is a method originally used to transfer digits in the telephone set to the
local switch.
25917.
25918.
A. tone dialing

25919.
B. dial pulsing
25920.
C. battery and ground pulsing
25921.
D. reverse battery pulsing
25922.
25923.
114. It is the time required to propagate a change in an AM envelope through a
transmission medium
25924.
25925.
A. envelope delay distortion
25926.
B. phase delay
25927.
C. envelope delay
25928.
D. propagation time
25929.
25930.
115. It is the primary source of transmission errors in data circuits
25931.
25932.
A. impulse noise
25933.
B. crosstalk
25934.
C. gain hits
25935.
D. interference
25936.
25937.
116. It eliminates the echo by electrically subtracting it from the original signal
rather than disabling the amplifier in the return circuit.
25938.
25939.
A. echo suppressors
25940.
B. echo limiters
25941.
C. echo cancellers
25942.
D. any of these
25943.
117. In telephony, functions that involve the actual transmission of a subscriber’s
messages and any necessary control signals.
25944.
25945.
A. transmission functions
25946.
B. signaling functions
25947.
C. maintenance functions
25948.
D. calling functions
25949.
25950.
118. The first computer-controlled central office switching system used in PSTN
25951.
25952.
A. No.7 ESS
25953.
B. No.2 ESS
25954.
C. No.5 ESS
25955.
D. No. 1 ESS
25956.
25957.
119. It is an exchange without a local loops connected to it
25958.
25959.
A. double office
25960.
B. tandem office
25961.
C. exchange office

25962.
D. local office
25963.
25964.
120. The 5-class switching hierarchy is a __________ scheme that establishes an
end-to-end route mainly through trial and error.
25965.
25966.
A. interleaved switching
25967.
B. progressive switching
25968.
C. point-to-point switching
25969.
D. step-by-step switching
25970.
25971.
121. The frequency range of maximum voice energy is between
25972.
25973.
A. 150 and 300 Hz
25974.
B. 300 and 3400 Hz
25975.
C. 250 and 500 Hz
25976.
D. 100 and 300 Hz
25977.
25978.
122. The oldest of the automatic switching system
25979.
25980.
A. manual switching
25981.
B. step-by-step
25982.
C. common control
25983.
D. Electronic
25984.
25985.
123. Group 3 fax used which modulation?
25986.
25987.
A. QAM
25988.
B. FSK
25989.
C. Vestigial sideband AM
25990.
D. FM
25991.
25992.
124. Signals that provides information in the form of announcements, such as
number changed to another number, a number no longer in service, and so on
25993.
25994.
A. addressing
25995.
B. ringing
25996.
C. controlling
25997.
D. supervising
25998.
25999.
125. The switch closure in an off-hook condition causes a range of dc current to
flow on the loop, what is that range of current?
26000.
26001.
A. 23 mA to 50 mA
26002.
B. 15 mA to 30 mA
26003.
C. 10 mA to 20 mA
26004.
D. 20 mA to 80 mA

26005.
26006.
126. These are unused sections of cables that are connected in shunt working
cable pair, such as a local loop. They are used for party lines to connect to the same local
loop.
26007.
26008.
A. cross-connect loop
26009.
B. drop wire tap
26010.
C. bridge tap
26011.
D. wire tap
26012.
26013.
127. The time delay encountered by a signal as it propagates from a source to a
destination is called ____________.
26014.
26015.
A. propagation time
26016.
B. phase delay
26017.
C. holding time
26018.
D. system delay time
26019.
26020.
128. It is the decrease in gain of more than 12 dB lasting longer than 4 ms and is a
characteristics of temporary open circuit conditions and are generally caused by deep
fades in radio facilities or by switching delays.
26021.
26022.
A. echo
26023.
B. jitter
26024.
C. gain hits
26025.
D. dropouts
26026.
26027.
129. It is similar to the local loop except that it is used to interconnect two
telephone offices.
26028.
26029.
A. trunk lines
26030.
B. subscriber loop
26031.
C. local lines
26032.
D. subscriber lines
26033.
26034.
130. Calls that are placed between two stations that are connected to different
local exchanges.
26035.
26036.
A. interoffice calls
26037.
B. interswitch calls
26038.
C. interexchange calls
26039.
D. any of these
26040.
26041.
131. _________ is defined as a momentary on-hook condition that causes loop
making and breaking from the telephone set dialer toward the central office.
26042.

26043.
A. dial tone
26044.
B. dial pulsing
26045.
C. on-hook
26046.
D. off-hook
26047.
26048.
132. In facsimile technology, it is a number derived from the width-height ratio.
26049.
26050.
A. numerical aperture
26051.
B. scanning spot
26052.
C. index of cooperation
26053.
D. cut-off frequency
26054.
26055.
133. In RJ-11, the RJ stands for
26056.
26057.
A. Recommended Jack
26058.
B. Released Jack
26059.
C. Registered Jack
26060.
D. Radio Jack
26061.
26062.
134. A cross-connect point used to distribute the larger feeder cable into smaller
distribution cables
26063.
26064.
A. SLIC
26065.
B. serving area interface
26066.
C. LATA
26067.
D. cross-connect cabinet
26068.
26069.
135. The process used to improve a basic telephone channel is called
26070.
26071.
A. line turnaround
26072.
B. line conditioning
26073.
C. line sensing
26074.
D. line improvement
26075.
26076.
136. In telephony, functions that identify and connect subscribers to a suitable
transmission path
26077.
26078.
A. transmission functions
26079.
B. signaling functions
26080.
C. switching functions
26081.
D. calling functions
26082.
26083.
137. The telephone switching plan that allows a certain degree of route selection
when establishing a phone call.
26084.
26085.
A. NPA

26086.
B. switching hierarchy
26087.
C. toll hierarchy
26088.
D. interoffice hierarchy
26089.
26090.
138. It provides access to the SS7 network access to databases used by switches
inside and outside of the network, and transfer of SS7 messages to other signaling points
within the network.
26091.
26092.
A. point codes
26093.
B. signaling points
26094.
C. service points
26095.
D. switching points
26096.
26097.
139. The connection between the subscriber and his own particular central office.
26098.
26099.
A. trunk
26100.
B. line
26101.
C. signaling
26102.
D. pulsing
26103.
140. It is a measure of how well we can distinguish closely spaced objects or identify
small items on a print.
26104.
26105.
A. resolution
26106.
B. legibility
26107.
C. contrast
26108.
D. hue
26109.
26110.
141. It is the exchange of signaling messages over local loops between stations
and telephone company switching machines
26111.
A. loop signaling
26112.
B. station signaling
26113.
C. interoffice signaling
26114.
D. pulse signaling
26115.
26116.
142. Modern paging system uses what modulation technique?
26117.
26118.
A. FSK and QPSK
26119.
B. PSK and QAM
26120.
C. ASK and FSK
26121.
D. FSK and PSK
26122.
26123.
143. The talker hears a returned portion of the signal as an echo, what is the
round-trip time of delay for an echo to quite annoying?
26124.
26125.
A. 15 msec

26126.
B. 25 msec
26127.
C. 35 msec
26128.
D. 45 msec
26129.
26130.
144. When subscriber initiates a long distance calls, the local exchange connects
the caller to the toll office through a facility called ________.
26131.
26132.
A. interoffice toll trunk
26133.
B. intraoffice toll trunk
26134.
C. interoffice exchange trunk
26135.
D. intraoffice exchange trunk
26136.
26137.
145. Range of speech power
26138.
26139.
A. 100 – 1000 uW
26140.
B. 10 – 100 uW
26141.
C. 10 – 1000 uW
26142.
D. 1000 – 10000 uW
26143.
26144.
146. Which resolution produces the best quality fax?
26145.
26146.
A. 96 lpi
26147.
B. 150 lpi
26148.
C. 200 lpi
26149.
D. 400 lpi
26150.
26151.
147. Facsimile standards are set by the
26152.
26153.
A. FCC
26154.
B. DOD
26155.
C. CCITT
26156.
D. IEEE
26157.
26158.
148. Telephone set component placed directly across the tip and ring to alert the
designation party of an incoming call
26159.
26160.
A. transmitter
26161.
B. receiver
26162.
C. ringer
26163.
D. dialer
26164.
26165.
149. The reference frequency of a typical voice-band circuit is typically around
_________.
26166.
26167.
A. 1500 Hz
26168.
B. 1300 Hz

26169.
C. 1700 Hz
26170.
D. 1800 Hz
26171.
26172.
150. The most versatile and popular crossbar switch was __________.
26173.
26174.
A. #4YB
26175.
B. 5#YB
26176.
C. #5XB
26177.
D. #5ZB
26178.
26179.
151. A telephone service that uses a common 800 area code regardless of the
location of the destination.
26180.
26181.
A. wide area telephone service
26182.
B. local area telephone service
26183.
C. metropolitan area telephone service
26184.
D. personal area telephone service
26185.
26186.
152. A device that combines the transmitter and the receiver to operate over the
same wire pair.
26187.
26188.
A. balancing network
26189.
B. diaphragm
26190.
C. hybrid
26191.
D. relay
26192.
26193.
153. Group 2 fax that uses fax standard is
26194.
26195.
A. SSB
26196.
B. FSK
26197.
C. Vestigial sideband AM
26198.
D. PSK
26199.
154. A signal sent from the central office to a subscriber whenever there is an
incoming call
26200.
26201.
A. busy signal
26202.
B. ringing signal
26203.
C. ringback signal
26204.
D. dial tone
26205.
26206.
155. It is defined as the optimum level of a test tone on a channel at some point in
a communications system.
26207.
26208.
A. transmission level point
26209.
B. data level point
26210.
C. voice level point

26211.
D. baseband transmission point
26212.
26213.
156. A type of crosstalk which is caused by inadequate control of the frequency
response of the transmission system, poor filter design, or poor filter performance.
26214.
26215.
A. single-channel crosstalk
26216.
B. transmittance crosstalk
26217.
C. linear crosstalk
26218.
D. coupling crosstalk
26219.
26220.
157. Class of switching office that could provide service to geographical regions
varying in size from part of the state to all of several states, depending on population
density.
26221.
26222.
A. sectional center
26223.
B. end office
26224.
C. regional center
26225.
D. toll center
26226.
26227.
158. By definition, speech power is equal to v.u. reading minus 1.4 dB plus log of
N, where N is
26228.
26229.
A. The number of lines used
26230.
B. The number of transmitters used
26231.
C. The number of persons speaking
26232.
D. The number of listeners listening
26233.
26234.
159. The most commonly used light sensor in a modern fax machine is a
26235.
26236.
A. Phototube
26237.
B. Phototransistor
26238.
C. Liquid-crystal display
26239.
D. Charged coupled device
26240.
26241.
160. Systems that are simplex wireless communications systems designed to alert
subscribers of awaiting messages
26242.
26243.
A. paging
26244.
B. searching
26245.
C. texting
26246.
D. calling
26247.
26248.
161. It can be defined as any disturbance created in a communications channel by
signals in other communications channel.
26249.
26250.
A. crosstalk

26251.
B. interference
26252.
C. hits
26253.
D. jitter
26254.
26255.
162. Type of Class 4 toll center which provides human operators for both outward
and inward calling service.
26256.
26257.
A. Class 4P
26258.
B. Class 5
26259.
C. Class 4C
26260.
D. Class 1
26261.
26262.
163. A type of signaling was developed as an alternative to loop signaling.
26263.
26264.
A. ear and mouth
26265.
B. duplex
26266.
C. loop pulsing
26267.
D. interoffice calling
26268.
26269.
164. Signals that provide the routing information, such as calling and called
numbers.
26270.
26271.
A. routing
26272.
B. calling
26273.
C. controlling
26274.
D. addressing
26275.
26276.
165. Phase jitters occur at what frequency?
26277.
26278.
A. less than 300 Hz
26279.
B. more than 300 Hz
26280.
C. more than 400 Hz
26281.
D. more than 300 Hz but less than 400 Hz
26282.
26283.
166. 10 or more subscribers connected in a central office exchange using same
local loop
26284.
A. wire tapping
26285.
B. party lines
26286.
C. eaves dropping lines
26287.
D. monitor lines
26288.
26289.
167. He designed and built the first transmitter and receiver for a telephone set.
26290.
26291.
A. Alexander Graham Bell
26292.
B. Alexander Bain
26293.
C. Antonio Meucci

26294.
D. Philipp Reis
26295.
26296.
168. If a switching machine is set to accept pulses at a rate of 10 pulses per
second with a 60% break, find the make interval of the switch.
26297.
26298.
A. 60 ms
26299.
B. 100 ms
26300.
C. 40 ms
26301.
D. 25 ms
26302.
26303.
169. How many point-to-point links are required to connect 50 telephones
together?
26304.
26305.
A. 2255
26306.
B. 1225
26307.
C. 2250
26308.
D. 1552
26309.
26310.
170. The first commercial switchboard was installed in
26311.
26312.
A. Connecticut
26313.
B. Boston
26314.
C. Pennsylvania
26315.
D. Washington
26316.
26317.
171. Where is a fax scanner found?
26318.
26319.
A. at the end of fax signals
26320.
B. at origin of fax signals
26321.
C. at receive end of fax system
26322.
D. at the input of a fax transmitter
26323.
26324.
172. What is the standard scanning LPI rates?
26325.
26326.
A. 120
26327.
B. 25
26328.
C. 400
26329.
D. 195
26330.
26331.
173. What tone is used to start fax?
26332.
26333.
A. 400 Hz
26334.
B. 100 Hz
26335.
C. 300 Hz
26336.
D. 500 Hz
26337.

26338.
174. What tone is used to stop fax?
26339.
26340.
A. 450 Hz
26341.
B. 500 Hz
26342.
C. 150 Hz
26343.
D. 250 Hz
26344.
26345.
175. What tones carry map information using facsimile?
26346.
26347.
A. 1300 Hz and 2400 Hz
26348.
B. 2400 Hz and 2500 Hz
26349.
C. 1200 Hz and 2400 Hz
26350.
D. 1500 Hz and 2300 Hz
26351.
26352.
176. The following frequencies are developed using 1.8 kHz used for scanner in
facsimile, except:
26353.
26354.
A. 300 Hz
26355.
B. 100 Hz
26356.
C. 450 Hz
26357.
D. 60 Hz
26358.
26359.
177. To what is the output of a scanner fed in fax?
26360.
26361.
A. transmitter
26362.
B. receiver
26363.
C. mixer
26364.
D. oscillator
26365.
26366.
178. Basically, in facsimile, what is a scanner helix?
26367.
26368.
A. clear sided drum with one turn scratch
26369.
B. clear sided drum with two turn scratch
26370.
C. opaque sided drum with one turn scratch
26371.
D. opaque sided drum with two turn scratch
26372.
26373.
179. A recorder helix in facsimile?
26374.
A. insulated drum with one turn wire
26375.
B. opaque drum with one turn scratch
26376.
C. clear sided with one turn wire
26377.
D. insulated drum with one turn scratch
26378.
26379.
180. In fax, the following are scanner signals where the switcher switch in except:
26380.
26381.
A. 300 Hz
26382.
B. phasing signal

26383.
26384.
26385.
26386.
26387.
26388.
26389.
26390.
26391.
26392.
26393.
26394.
26395.
26396.
26397.
26398.
26399.
26400.
other?
26401.
26402.
26403.
26404.
26405.
26406.
26407.
26408.
26409.
26410.
26411.
26412.
26413.
26414.
Hz?
26415.
26416.
26417.
26418.
26419.
26420.
26421.
26422.
26423.
26424.
26425.
26426.

C. 90 Hz
D. map signals
181. With what type transmitter is fax transmitted on HF?
A. AM
B. FM
C. PM
D. SSB
182. With what type transmitter is fax transmitted on VHF?
A. FM
B. PM
C. SSB
D. AM
183. The helix wire forms one end of the circuit of facsimile; what forms the
A. insulated wire
B. drum
C. blade
D. transmit circuit
184. What emf is required across the circuit in facsimile to form a dark spot?
A. 40 V
B. 60 V
C. 25 V
D. 70 V
185. In a facsimile recorder what is used to make 1,500-Hz ac stronger than 2300
A. non-linear slope filter
B. linear slope filter
C. active slope filter
D. passive slope filter
186. In a recorder of facsimile, what is used to generate 60-Hz ac?
A. 3.0 kHz oscillator and logic gates
B. 2.4 kHz mixer and logic gates
C. 3.0 kHz oscillator and logic divider
D. 2.4 kHz oscillator and logic divider

26427.
187. If the tuning meter reads full scale, what would this indicate in facsimile?
26428.
26429.
A. 1300 signal
26430.
B. 2400 signal
26431.
C. 1400 signal
26432.
D. 1500 signal
26433.
26434.
188. If the tuning meter reads midscale, what would this indicate in facsimile?
26435.
26436.
A. average
26437.
B. mistuned
26438.
C. peak
26439.
D. minimum
26440.
26441.
189. If the tuning meter reads low-scale, what would this indicate in facsimile?
26442.
26443.
A. 1500 signal
26444.
B. 1700 signal
26445.
C. 2300 signal
26446.
D. 2400 signal
26447.
26448.
190. Why is the blade an endless loop in facsimile?
26449.
26450.
A. wears faster
26451.
B. wears slower
26452.
C. wears average speed
26453.
D. never wears
26454.
26455.
191. What should bring the left margin of the map to the left side of the paper in
the recorder of facsimile?
26456.
26457.
A. map signals
26458.
B. phasing signals
26459.
C. automatic switch
26460.
D. 90 Hz
26461.
26462.
26463.
26464.
26465.
26466.
26467.
26468.

26469. MULTIPLE CHOICE QUESTIONS IN

26470. FIBER OPTICS
26471.

Electronics Systems and Technologies
26472. By
26473.

Melvin C. Arceo
26474.
26475.
26476.
26477.
26478.
26479.
26480.

26481.
26482.
26483.

26484. ENCODED BY:
26485. RIVERA, Billy Joe S.
26486.

1. A device that was constructed from mirrors and selenium detectors that
transmitted sound waves over a beam of light.
26487.
26488.
A. lightphone
26489.
B. photophone
26490.
C. cameraphone
26491.
D. walletphone
26492.
26493.
2. Which fiber-optic system is better?
26494.
26495.
A. 3 repeaters
26496.
B. 8 repeaters
26497.
C. 11 repeaters
26498.
D. 20 repeaters
26499.
26500.
3. What is the frequency limit of a copper wire?
26501.
26502.
A. approximately 0.5 MHz
26503.
B. approximately 1.0 MHz
26504.
C. approximately 40 GHz
26505.
D. none of the above
26506.
26507.
4. They were granted patents for scanning and transmitting television images
through uncoated fiber cables.
26508.
26509.
A. Baird and Hansel

26510.
B. Bockham and Kao
26511.
C. Kapron and Keck
26512.
D. Maiman and Schawlow
26513.
26514.
5. The product of the bit rate and distance of a fiber-optic system is 2 Gbits-km/s.
What is the maximum rate at 5 km?
26515.
26516.
A. 100 Mbits/s
26517.
B. 200 Mbits/s
26518.
C. 400 Mbits/s
26519.
D. 1000 Gbits/s
26520.
26521.
6. Approximately what is the frequency limit of the optical fiber?
26522.
26523.
A. 20 MHz
26524.
B. 1 MHz
26525.
C. 100 MHz
26526.
D. 40 GHz
26527.
26528.
7. They experimented with light transmission cables through bundle of fibers and
lead to the development of flexible fiberscope.
26529.
26530.
A. Townes, Schawlow and Kao
26531.
B. Maiman, Kao and Bockham
26532.
C. Maurer, Kapron and Keck
26533.
D. Van Heel, Hopkins and Kapany
26534.
26535.
8. Photodiodes operate properly with
26536.
26537.
A. forward bias
26538.
B. reverse bias
26539.
C. neither forward nor reverse bias
26540.
D. either forward or reverse bias
26541.
26542.
9. He coined the term “fiber optics” in 1956.
26543.
26544.
A. Kapany
26545.
B. Kao
26546.
C. Bockham
26547.
D. Keck
26548.
26549.
10. They wrote a paper describing how it was possible to use stimulated emission
for amplifying light waves (laser) as well as microwaves (maser).
26550.
26551.
A. Theodore Maiman
26552.
B. KC Kao and GA Bockham

26553.
26554.
26555.
26556.
26557.
26558.
26559.
26560.
26561.
26562.
26563.
26564.
26565.
26566.
26567.
26568.
26569.
26570.
26571.
26572.
26573.
26574.
26575.
26576.
26577.
26578.
26579.
26580.
26581.
26582.
26583.
26584.
26585.
26586.
26587.
26588.
26589.
26590.
26591.
26592.
26593.
26594.
26595.
26596.
26597.
26598.

C. Charles Townes and Arthur Schawlow
D. Kapron, Keck and Maurer
11. The scientist who built the first optical maser
A. Charles Townes
B. GA Bockham
C. Theodore Maiman
D. ACS Van Heel
12. A single fiber can handle as many voice channels as
A. a pair of copper conductors
B. a 1500-pair cable
C. a 500-pair cable
D. a 1000-pair cable
13. They proposed a new communication medium using cladded fiber cables.
A. Kao and Bockham
B. Maiman, Kao and Bockham
C. Kapron, Keck and Maurer
D. Maiman and Schawlow
14. An incident ray can be defined as
A. a light ray reflected from a flat surface
B. a light directed toward a surface
C. a diffused light ray
D. a light ray that happens periodically
15. Developed an optical fiber with losses less that 2 dB/km
A. Kao and Bockham
B. Maiman, Kao and Bockham
C. Maiman and Schawlow
D. Kapron, Keck and Maurer
16. The band of light frequencies that are too high to be seen by the human eye.
A. Ultraviolet
B. Visible light
C. Infrared
D. Yellow
17. Which of the following is the fastest light sensor?

26599.
26600.
26601.
26602.
26603.
26604.
26605.
26606.
26607.
26608.
26609.
26610.
26611.
26612.
26613.
26614.
26615.
26616.
26617.
26618.
26619.
26620.
26621.
26622.
26623.
26624.
26625.
26626.
26627.
26628.
26629.
26630.
26631.
26632.
26633.
26634.
26635.
26636.
26637.
26638.
26639.
26640.
26641.
26642.
26643.
26644.

A. PIN photodiode
B. Photovoltaic diode
C. Photodiode
D. Avalanche photodiode
18. Range of infrared
A. 360 nm to 440 nm
B. 670 nm to 10^3 nm
C. 110 nm to 240 nm
D. 770 nm to 10^6 nm
19. The term dispersion describes the process of
A. separating light into its component frequencies
B. reflecting light from a smooth surface
C. the process by which light is absorbed by an uneven rough surface
D. light scattering
20. The band of light frequencies to which human eye will respond
A. Infrared
B. Visible light
C. Ultraviolet
D. Cosmic ray
21. Laser light is very bright because it is
A. pure
B. white
C. coherent
D. monochromatic
22. Which of the following is the fastest light sensor?
A. PIN photodiode
B. Photovoltaic diode
C. Photodiode
D. Avalanche photodiode
23. Range of wavelength of visible light
A. 670 nm to 10^3 nm
B. 440 nm to 540 nm
C. 110 nm to 240 nm
D. 390 nm to 770 nm

26645.
26646.
24. The band of light frequencies that are too low to be seen by the human eye
26647.
26648.
A. Infrared
26649.
B. X-rays
26650.
C. Visible
26651.
D. Ultraviolet
26652.
26653.
25. Which of the following terms best describes the reason that light is refracted at
different angles?
26654.
26655.
A. Photon energy changes with wavelength
26656.
B. Light is refracted as a function of surface smoothness
26657.
C. The angle is determined partly by a and b
26658.
D. The angle is determined by the index of the materials
26659.
26660.
26. Range of wavelengths of ultraviolet
26661.
26662.
A. 670 nm to 10^3 nm
26663.
B. 440 nm to 540 nm
26664.
C. 110 nm to 240 nm
26665.
D. 10 nm to 390 nm
26666.
26667.
27. Single frequency light is called
26668.
26669.
A. pure
26670.
B. intense
26671.
C. coherent
26672.
D. monochromatic
26673.
26674.
28. The coating in a fiber helps protect fiber from moisture, which reduces the
possibility of the occurrence of a detrimental phenomenon called
26675.
26676.
A. static fatigue
26677.
B. mechanical fatigue
26678.
C. stress fatigue
26679.
D. coating fatigue
26680.
26681.
29. The term critical angle describes
26682.
26683.
A. the point at which light is refracted
26684.
B. the point at which light becomes invisible
26685.
C. the point at which light has gone from the refractive mode to the reflective
mode
26686.
D. the point at which light has crossed the boundary layers from one index to
another

26687.
26688.
30. The ratio of the speed of light in air to the speed of light in another substance
is called
26689.
26690.
A. speed factor
26691.
B. index of reflection
26692.
C. index of refraction
26693.
D. speed gain
26694.
26695.
31. The three essential types of fiber commonly used today except:
26696.
26697.
A. Plastic core and cladding
26698.
B. Plastic core and glass cladding
26699.
C. Glass core and glass cladding (SCS)
26700.
D. Glass core and plastic cladding (PCS)
26701.
26702.
32. What phenomenon will result if the glass fiber is exposed to long periods of
high humidity?
26703.
26704.
A. stress fatigue
26705.
B. core corrosion
26706.
C. stress corrosion
26707.
D. cladding corrosion
26708.
33. The law that states “When visible light of high frequency electromagnetic
radiation illuminates a metallic surface, electrons are emitted” is known as
____________.
26709.
26710.
A. Einstein law of photon
26711.
B. Marconi’s law
26712.
C. Maxwell’s law
26713.
D. Plank’s law
26714.
26715.
34. Both LEDs and ILDs operate correctly with
26716.
26717.
A. forward bias
26718.
B. reverse bias
26719.
C. neither forward nor reverse bias
26720.
D. either forward or reverse bias
26721.
26722.
35. Any energy above the ground state is called ___________.
26723.
26724.
A. normal state
26725.
B. above-ground state
26726.
C. excited state
26727.
D. spontaneous state
26728.

26729.
36. The process of decaying from one energy level to another energy level is
called __________.
26730.
26731.
A. Spontaneous emission
26732.
B. Excited emission
26733.
C. Absorption
26734.
D. Any of these
26735.
26736.
37. The process of moving from one energy level to another is called
____________.
26737.
26738.
A. Spontaneous emission
26739.
B. Excited emission
26740.
C. Absorption
26741.
D. Spontaneous decay
26742.
26743.
38. Most fiber optic light sources emit light in which spectrum?
26744.
26745.
A. visible
26746.
B. infrared
26747.
C. ultraviolet
26748.
D. X-ray
26749.
26750.
39. A packet of energy which is equal to the difference between the two energy
levels.
26751.
26752.
A. Photons
26753.
B. Electronvolt
26754.
C. Quantum
26755.
D. Quanta
26756.
26757.
40. It is the science of measuring only light waves that are visible to the human
eye.
26758.
26759.
A. Radiometry
26760.
B. Photometry
26761.
C. Ophthalmology
26762.
D. Optometry
26763.
26764.
41. The refractive index number is
26765.
26766.
A. a number which compares the transparency of a material with that of air
26767.
B. a number of assigned by the manufacturer to the fiber in question
26768.
C. a number which determines the core diameter
26769.
D. a term describing core elasticity
26770.

26771.
42. It is a science of measuring light throughout the entire electromagnetic
spectrum
26772.
26773.
A. Radiometry
26774.
B. Photometry
26775.
C. Ophthalmology
26776.
D. Optometry
26777.
26778.
43. Which light emitter is preferred for high-speed data in a fiber-optic system?
26779.
26780.
A. incandescent
26781.
B. LED
26782.
C. neon
26783.
D. laser
26784.
26785.
44. Light intensity is generally described in terms of __________ and measured in
_________.
26786.
26787.
A. Luminous flux density; Lumens per unit area
26788.
B. Luminous flux intensity; Lumens per unit area
26789.
C. Luminous flux density; Lumens per unit volume
26790.
D. Luminous flux intensity; Lumens per unit volume
26791.
26792.
45. In radiometric terms, it measures the rate at which electromagnetic waves
transfer light energy
26793.
26794.
A. Optical radiation
26795.
B. Optical impedance
26796.
C. Optical illusion
26797.
D. Optical power
26798.
46. It is described as the flow of light energy past a given point in a specified time
26799.
26800.
A. Optical radiation
26801.
B. Optical impedance
26802.
C. Optical illusion
26803.
D. Optical power
26804.
26805.
47. The term single mode and multimode are best described as
26806.
26807.
A. a number of fibers placed into fiber-optic cable
26808.
B. the number of voice channels each fiber can support
26809.
C. the number of wavelengths each fiber can support
26810.
D. the index number
26811.
26812.
48. Optical power is sometimes called __________.
26813.

26814.
A. Radiant emission
26815.
B. Radiant power
26816.
C. Radiant flux
26817.
D. Radiant optics
26818.
26819.
49. In refraction that occurs in air/glass interfaces, among the visible light, which
is bent the most?
26820.
26821.
A. red
26822.
B. violet
26823.
C. yellow
26824.
D. green
26825.
26826.
50. Fiber-optic cables with attenuation of 1.8, 3.4, 5.9 and 18 dB are linked
together. The total loss is
26827.
26828.
A. 7.5 dB
26829.
B. 19.8 dB
26830.
C. 29.1 dB
26831.
D. 650 dB
26832.
26833.
51. In refraction that occurs in air/glass interfaces, among the visible light, which
is the bent the least?
26834.
26835.
A. violet
26836.
B. blue
26837.
C. red
26838.
D. orange
26839.
26840.
52. Ratio of the velocity of propagation of a light ray in free space to the velocity
of propagation of a light ray in free space in a given material.
26841.
26842.
A. refractive index
26843.
B. standing wave ratio
26844.
C. velocity factor
26845.
D. propagation velocity
26846.
26847.
53. It is the angle at which the propagating ray strikes the interface with respect to
the normal.
26848.
26849.
A. refracted angle
26850.
B. incident angle
26851.
C. reflected angle
26852.
D. critical angle
26853.

26854.
54. It is the angle formed between the propagating ray and the normal after the ray
has entered the second medium.
26855.
26856.
A. angle of incidence
26857.
B. angle of reflection
26858.
C. propagation angle
26859.
D. angle of refraction
26860.
26861.
55. Between silicon and gallium arsenide, which has the greatest index of
refraction?
26862.
26863.
A. Gallium arsenide
26864.
B. Neither of silicon nor gallium arsenide
26865.
C. Silicon
26866.
D. They are equal
26867.
26868.
56. A fiber-optic cable has a loss of 15dB/km. The attenuation in a cable 1000 ft
long is
26869.
26870.
A. 4.57 dB
26871.
B. 9.3 dB
26872.
C. 24 dB
26873.
D. 49.2 dB
26874.
26875.
57. Medium 1 is a glass (n1=1.5) and medium 2 is an ethyl alcohol (n2=1.36). For
an angle of incidence of 30 degrees, determine the angle of refraction.
26876.
26877.
A. 44.5 degrees
26878.
B. 14.56 degrees
26879.
C. 33.47 degrees
26880.
D. 75 degrees
26881.
26882.
58. The minimum angle of incidence at which the light ray may strike the
interface of two media and result in an angle of refraction of 90 degrees or greater.
26883.
26884.
A. optimum angle
26885.
B. angle of refraction
26886.
C. refracted angle
26887.
D. critical angle
26888.
26889.
59. The higher the index number
26890.
26891.
A. the higher the speed of light
26892.
B. the lower the speed of light
26893.
C. has no effect on the speed of light
26894.
D. the shorter the wavelength propagation

26895.
26896.
60. The maximum angle in which external light rays may strike the air/glass
interface and still propagate down the fiber.
26897.
26898.
A. Acceptance cone half-angle
26899.
B. Acceptance cone
26900.
C. Critical angle
26901.
D. Angle of incidence
26902.
26903.
61. It is the figure of merit used to measure the magnitude of the acceptance
angle.
26904.
26905.
A. acceptance angle
26906.
B. numerical aperture
26907.
C. index profile
26908.
D. refractive index
26909.
26910.
62. The effect of a large magnitude of the numerical aperture
26911.
26912.
A. The amount of external light the fiber will accept is greater.
26913.
B. The amount of external light the fiber will accept is less.
26914.
C. The amount of modal dispersion will be less.
26915.
D. The amount of chromatic dispersion will be greater.
26916.
26917.
63. Only one path for light rays to take down the fiber
26918.
26919.
A. Multimode
26920.
B. Step-index
26921.
C. Single mode
26922.
D. Graded index
26923.
26924.
64. More than one path for light rays to take down the fiber
26925.
26926.
A. Multimode
26927.
B. Step-index
26928.
C. Single mode
26929.
D. Graded index
26930.
26931.
65. The three major groups of the optical system are
26932.
26933.
A. the components, the data rate and the response time
26934.
B. the source, the link and the receiver
26935.
C. the transmitter, the cable and the receiver
26936.
D. the source, the link and the detector
26937.
26938.
66. Infrared light has a wavelength that is

26939.
26940.
A. less than 400 nm
26941.
B. more than 700 nm
26942.
C. less than 700 nm
26943.
D. a little over 400 nm
26944.
26945.
67. How many modes possible with a multimode step-index with a core diameter
of 50 um, a core refractive index of 1.6, a cladding refractive index of 1.584, and a
wavelength of 1300 nm.
26946.
26947.
A. 456
26948.
B. 213
26949.
C. 145
26950.
D. 372
26951.
26952.
68. It is a graphical representation of the magnitude of the refractive index across
the fiber.
26953.
26954.
A. mode
26955.
B. index profile
26956.
C. numerical aperture
26957.
D. refractive index
26958.
26959.
69. A type of index profile of an optical fiber that has a central core and outside
cladding with a uniform refractive index
26960.
26961.
A. multimode
26962.
B. graded index
26963.
C. step-index
26964.
D. single mode
26965.
26966.
70. A type of index of an optical fiber that has no cladding and whose central core
has a non-uniform refractive index.
26967.
26968.
A. graded index
26969.
B. multimode
26970.
C. single mode
26971.
D. step-index
26972.
26973.
71. Results in reduction in the power of light wave as it travels down the cable.
26974.
26975.
A. power loss
26976.
B. absorption loss
26977.
C. resistive loss
26978.
D. heat loss
26979.

26980.
72. Which of the following is not a factor in cable light loss?
26981.
26982.
A. reflection
26983.
B. absorption
26984.
C. scattering
26985.
D. dispersion
26986.
26987.
73. It is analogous to power dissipation to copper cables, impurities in the fiber
absorb the light and covert it to heat.
26988.
26989.
A. power loss
26990.
B. absorption loss
26991.
C. resistive loss
26992.
D. heat loss
26993.
26994.
74. It is caused by valence electrons in the silica material from which the fiber are
manufactured.
26995.
26996.
A. ion resonance absorption
26997.
B. infrared absorption
26998.
C. ultraviolet absorption
26999.
D. visible light absorption
27000.
27001.
75. It is a result of photons of light that are absorbed by the atoms of the glass
core molecule.
27002.
27003.
A. ion resonance absorption
27004.
B. infrared absorption
27005.
C. ultraviolet absorption
27006.
D. visible light absorption
27007.
27008.
76. It is caused by hydroxide ions in the material
27009.
27010.
A. visible light absorption
27011.
B. infrared absorption
27012.
C. ultraviolet absorption
27013.
D. ion resonance absorption
27014.
77. Which type of fiber-optic cable has the least modal dispersion?
27015.
27016.
A. single-mode step-index
27017.
B. multimode step-index
27018.
C. single-mode graded-index
27019.
D. multimode graded-index
27020.
27021.
78. For a single mode optical cable with 0.25dB/km loss, determine the optical
power 100km from a 0.1-mW light source.

27022.
27023.
A. -45 dBm
27024.
B. -15 dBm
27025.
C. -35 dBm
27026.
D. -25dBm
27027.
27028.
79. Light rays that are emitted simultaneously from an LED and propagated down
an optical fiber do not arrive at the far end of the fiber at the same time results to
27029.
27030.
A. intramodal dispersion
27031.
B. pulse length dispersion
27032.
C. modal dispersion
27033.
D. wavelength dispersion
27034.
27035.
80. Chromatic dispersion can be eliminated by __________.
27036.
27037.
A. using a monochromatic light source
27038.
B. using a very small numerical aperture fiber
27039.
C. using a graded-index fiber
27040.
D. using a very sensitive photodetector
27041.
27042.
81. Type of bend that occurs as a result of differences in thermal contraction rates
between the core and the cladding material.
27043.
27044.
A. Macrobending
27045.
B. Microbending
27046.
C. Quad bending
27047.
D. Constant-radius bending
27048.
27049.
82. These bends are caused by excessive pressure and tension and generally occur
while fiber are bent during handling or installation.
27050.
27051.
A. microbending
27052.
B. macrobending
27053.
C. constant-radius bending
27054.
D. kinks
27055.
27056.
83. As light is coupled in a multiport deflective device, the power is reduced by
27057.
27058.
A. 1.5 dB
27059.
B. 0.1 dB
27060.
C. 0.5 dB
27061.
D. 0.001 dB
27062.
27063.
84. It is caused by the difference in the propagation time of light rays that take
different paths down the fiber.

27064.
27065.
A. modal dispersion
27066.
B. microbending
27067.
C. Rayleigh scattering
27068.
D. chromatic dispersion
27069.
27070.
85. How can modal dispersion reduced entirely?
27071.
27072.
A. Use a graded index fiber
27073.
B. Use a single-mode fiber
27074.
C. Use a monochromatic light source
27075.
D. Use a very sensitive light detector
27076.
27077.
86. It indicates what signal frequencies can be propagated through a given
distance of fiber cable.
27078.
27079.
A. Bandwidth Distance Product
27080.
B. Pulse width dispersion
27081.
C. Rise time
27082.
D. Cutoff frequency
27083.
27084.
87. For a 300-m optical fiber cable with a bandwidth distance product of 600
MHz-km, determine the bandwidth.
27085.
27086.
A. 5 GHz
27087.
B. 1 GHz
27088.
C. 2 GHz
27089.
D. 3 GHz
27090.
27091.
88. For an optical fiber 10 km long with a pulse spreading constant of 5 ns/km,
determine the maximum digital transmission rates using Return to Zero (RZ) and
Nonreturn to Zero (NRZ).
27092.
27093.
A. 5 Mbps and 10 Mbps
27094.
B. 10 Mbps and 5 Mbps
27095.
C. 10 Mbps and 20 Mbps
27096.
D. 20 Mbps and 10 Mbps
27097.
27098.
89. What is the spectral width of a standard LED?
27099.
27100.
A. 20 to 40 nm
27101.
B. 30 to 50 nm
27102.
C. 10 to 30 nm
27103.
D. 40 to 60 nm
27104.
27105.
90. What is the spectral width of an ILD?

27106.
27107.
A. 0.1 nm to 1 nm
27108.
B. 2 nm to 5 nm
27109.
C. 1 nm to 3 nm
27110.
D. 3 nm to 4 nm
27111.
27112.
91. When connector losses, splice losses and coupler losses are added, what is the
limiting factor?
27113.
27114.
A. source power
27115.
B. fiber attenuation
27116.
C. connector and splice loss
27117.
D. detector sensitivity
27118.
27119.
92. A pn-junction diode emits light by spontaneous emission
27120.
27121.
A. LED
27122.
B. APD
27123.
C. PIN
27124.
D. Zener diode
27125.
27126.
93. Which type of fiber optic cable is best for very high speed data?
27127.
27128.
A. single-mode step-index
27129.
B. multimode step-index
27130.
C. single-mode graded-index
27131.
D. multimode graded-index
27132.
27133.
94. A measure of conversion efficiency of a photodetector.
27134.
27135.
A. Efficiency
27136.
B. Responsivity
27137.
C. Dark current
27138.
D. Spectral response
27139.
27140.
95. The leakage current that flows through a photodiode with no light input
27141.
27142.
A. dark voltage
27143.
B. dark impedance
27144.
C. dark power
27145.
D. dark current
27146.
27147.
96. The time it takes a light induced carrier travel across the depletion region of
the semiconductor.
27148.
27149.
A. dispersion

27150.
B. response time
27151.
C. irradiance
27152.
D. transit time
27153.
27154.
97. The range of wavelength values that a given photodiode will respond.
27155.
27156.
A. spectral response
27157.
B. permeance
27158.
C. dark current
27159.
D. reluctance
27160.
27161.
98. The term responsivity as it applies to a light detector is best described as
27162.
27163.
A. the time required for the signal to go from 10 to 90 percent of maximum
amplitude
27164.
B. the ratio of the diode output current to the input optical power
27165.
C. the ratio of the input power to output power
27166.
D. the ratio of output current to input current
27167.
27168.
99. The minimum optical power a light detector can receive and still produce a
usable electrical output signal.
27169.
27170.
A. light responsivity
27171.
B. light sensitivity
27172.
C. light collectivity
27173.
D. illumination
27174.
27175.
100. Type of lasers that uses a mixture of helium and neon enclosed in glass tube.
27176.
27177.
A. gas lasers
27178.
B. solid lasers
27179.
C. semiconductor lasers
27180.
D. liquid lasers
27181.
27182.
101. Type of lasers that use organic dyes enclosed in glass tube for an active
medium.
27183.
27184.
A. liquid lasers
27185.
B. plasma lasers
27186.
C. neon lasers
27187.
D. ruby lasers
27188.
27189.
102. A popular light wavelength fiber-optic cable is
27190.
27191.
A. 0.7 micrometer
27192.
B. 1.3 micrometer

27193.
C. 1.5 micrometer
27194.
D. 1.8 micrometer
27195.
27196.
103. Type of lasers that use solid, cylindrical crystals such as ruby
27197.
27198.
A. solid lasers
27199.
B. ILD
27200.
C. gas lasers
27201.
D. liquid lasers
27202.
27203.
104. Type of lasers that are made from semiconductor ph-junctions commonly
called ILDs
27204.
27205.
A. semiconductor lasers
27206.
B. liquid lasers
27207.
C. plasma lasers
27208.
D. gas lasers
27209.
27210.
105. Which of the following is not a common application of fiber-optic cable?
27211.
27212.
A. computer networks
27213.
B. long-distance telephone system
27214.
C. closed-circuit TV
27215.
D. consumer TV
27216.
27217.
106. Total internal reflection takes place if the light ray strikes the interface at an
angle with what relationship to the critical angle?
27218.
27219.
A. less than
27220.
B. greater than
27221.
C. equal to
27222.
D. zero
27223.
27224.
107. Loss comparisons between fusion splices an mechanical splices
27225.
27226.
A. 1:10
27227.
B. 10:1
27228.
C. 20:1
27229.
D. 1:20
27230.
27231.
108. The operation of a fiber-optic cable is based on the principle of
27232.
A. refraction
27233.
B. reflection
27234.
C. dispersion
27235.
D. absorption
27236.

27237.
27238.
27239.
27240.
27241.
27242.
27243.
27244.
27245.
27246.
27247.
27248.
27249.
27250.
27251.
27252.
27253.
27254.
27255.
27256.
27257.
27258.
27259.
27260.
27261.
27262.
27263.
27264.
27265.
by
27266.
27267.
27268.
27269.
27270.
27271.
27272.
27273.
27274.
27275.
27276.
27277.
27278.
27279.
27280.
27281.

109. Which of the following is not a common type of fiber-optic cable?
A. single-mode step-index
B. multimode graded-index
C. single-mode graded-index
D. multimode step-index
110. Cable attenuation is usually expressed in terms of
A. loss per foot
B. dB/km
C. intensity per mile
D. voltage drop per inch
111. Which cable length has the highest attenuation?
A. 1 km
B. 2 km
C. 95 ft
D. 500 ft
112. The mechanical splice is best suited for
A. quicker installation under ideal condition
B. minimum attenuation losses
C. field service conditions
D. situations in which cost of equipment is not a factor
113. The upper pulse rate and information-carrying capacity of a cable is limited
A. pulse shortening
B. attenuation
C. light leakage
D. modal dispersion
114. The core of a fiber-optic cable is made of
A. air
B. glass
C. diamond
D. quartz
115. The core of fiber-optic cable is surrounded by
A. wire braid shield
B. Keviar

27282.
C. cladding
27283.
D. plastic insulation
27284.
27285.
116. The speed of light in plastic compared to the speed of light in air is
27286.
27287.
A. less
27288.
B. more
27289.
C. the same
27290.
D. zero
27291.
27292.
117. Which of the following is not a major benefit of a fiber-optic cable?
27293.
27294.
A. immunity from interference
27295.
B. no electrical safety problems
27296.
C. excellent data security
27297.
D. lower cost
27298.
27299.
118. EMD is best described by which statement?
27300.
27301.
A. 70 percent of the core diameter and 70% of the fiber NA should be filled
with light.
27302.
B. 70 percent of the fiber diameter and 70% of the cone of acceptance should be
filled with light.
27303.
C. 70 percent of input light should be measured at the output.
27304.
D. 70 percent of the unwanted wavelengths should be attenuated by the fiber.
27305.
27306.
119. The main benefit of light wave communications over microwaves or any
other communications media are
27307.
27308.
A. lower cost
27309.
B. better security
27310.
C. wider bandwidth
27311.
D. freedom from interface
27312.
27313.
120. Which of the following is not a part of the optical spectrum?
27314.
27315.
A. infrared
27316.
B. ultraviolet
27317.
C. visible color
27318.
D. x-rays
27319.
27320.
121. The wavelength of a visible extends from
27321.
27322.
A. 0.8 to 1.6 um
27323.
B. 400 to 750 nm
27324.
C. 200 to 660 nm

27325.
27326.
27327.
27328.
27329.
27330.
27331.
27332.
27333.
27334.
27335.
27336.
27337.
27338.
27339.
27340.
27341.
27342.
27343.
27344.
27345.
27346.
27347.
27348.
27349.
27350.
27351.
27352.
27353.
27354.
27355.
27356.
27357.
27358.
27359.
27360.
27361.
27362.
27363.
27364.
27365.
27366.
27367.

D. 700 to 1200 nm
122. Single-mode step-index cable has a core diameter in the range of
A. 100 to 1000 micrometer
B. 50 to 100 micrometer
C. 2 to 15 micrometer
D. 5 to 20 micrometer
123. Refraction is the
A. bending of light
B. reflection of light waves
C. distortion of light waves
D. diffusion of light waves
124. Which of the following cables will have the highest launch power capability?
A. 50/125/0.2
B. 85/125/0.275
C. 62.5/125/0.275
D. 100/140/0.3
125. Which type of fiber-optic cable is the most widely used?
A. single-mode step-index
B. multimode step-index
C. single-mode graded index
D. multimode graded index
126. The term power budgeting refers to
A. the cost of cable, connectors, equipment and installation
B. the loss of power due to defective components
C. the total power available minus the attenuation losses
D. the comparative costs of fiber and copper installations
127. It refers to the abrupt of change in refractive index from core to clad
A. step index
B. graded index
C. semi-graded index
D. half step index
27368.
27369.

27370.
27371.

27372. MULTIPLE CHOICE QUESTIONS IN

27373. AMPLITUDE
MODULATION
27374.

Electronics Systems and Technologies
27375. By
27376.

Melvin C. Arceo
27377.
27378.

27379.
27380.
27381.
27382.
27383.
27384.

27385. ENCODED BY:
27386. SANTOLLO, Dan Alvin
27387.

1. The process of impressing a low frequency information signals onto a highfrequency carrier signal is called _____.
27388.
a. demodulation
27389.
b. oscillation
27390.
c. modulation
27391.
d. amplification
27392.
2. A silicon varactor diode exhibits a capacitance of 200pF at zero bias. If it is in
parallel with a 60-pF capacitor and a 200-uH inductor, calculate the range of resonant
frequency as the diode varies through a reverse bias of 3 to 15V.
27393.
a. 679kHz to 2.13MHz
27394.
b. 966kHz to 1.15MHz
27395.
c. 355kHz to 3.12MHz
27396.
d. 143 kHz to 4.53MHz
27397.
3. A process where the received signal is transformed into its original form.
27398.
a. demodulation
27399.
b. damping
27400.
c. amplification
27401.
d. oscillation
27402.
4. It is the process of changing the amplitude of a relative high frequency carrier
signal in proportion with the instantaneous value of the modulating signal.
27403.
a. frequency modulation

27404.
b. digital modulation
27405.
c. phase modulation
27406.
d. analog modulation
27407.
5. Most of the power in an AM signal is in the
27408.
a. carrier
27409.
b. upper sideband
27410.
c. lower sideband
27411.
d. modulating signal
27412.
6. Amplitude modulation is the same as
27413.
a. linear mixing
27414.
b. analog multiplexing
27415.
c. signal summation
27416.
d. multiplexing
27417.
7. The shape of the amplitude-modulated wave is called ______.
27418.
a. sidebands
27419.
b. modulating signal
27420.
c. envelope
27421.
d. carrier signal
27422.
8. In a diode modulator, the negative half of the AM wave is supplied by
27423.
a. tuned circuit
27424.
b. transformer
27425.
c. capacitor
27426.
d. inductor
27427.
9. It is a term used to describe the amount of amplitude change present in an AM
waveform.
27428.
a. coefficient of modulation
27429.
b. any of these
27430.
c. depth of modulation
27431.
d. modulation index
27432.
10. When the modulation index in an AM wave is greater than one it will cause
_______.
27433.
a. any of these
27434.
b. splatter
27435.
c. overmodulation
27436.
d. buck-shot
27437.
11. The ideal value of modulation index in AM.
27438.
a. 1
27439.
b. 0
27440.
c. 100
27441.
d. infinity
27442.
12. When the amplitude of the information in an AM modulator is equal to zero,
what is the value of the modulation index?
27443.
a. 1
27444.
b. 0
27445.
c. 100
27446.
d. infinity

27447.
13. Amplitude modulation can be produced by
27448.
a. having the carrier vary a resistance
27449.
b. having the modulating signal vary a capacitance
27450.
c. varying the carrier frequency
27451.
d. varying the gain of the amplifier
27452.
14. When the modulation index is equal to zero, the total transmitted power is
equal to ________.
27453.
a. one of the sidebands
27454.
b. carrier
27455.
c. double sidebands
27456.
d. an AM wave
27457.
15. When the modulation takes place prior to the output element of the final stage
of the transmitter, prior to the collector of the output transistor in a transistorized
transmitter, this is called ______.
27458.
a. high-level modulation
27459.
b. low-level modulation
27460.
c. zero-modulation
27461.
d. constant modulation
27462.
16. A circuit that monitors the received signal level and sends a signal back to the
RF and IF amplifiers to adjust their gain automatically.
27463.
a. automatic phase control
27464.
b. automatic gain control
27465.
c. automatic frequency control
27466.
d. automatic volume control
27467.
17. When the modulation takes place in the final element of the final stage where
the carrier signal is at its maximum amplitude, it is called _____.
27468.
a. constant modulation
27469.
b. zero-modulation
27470.
c. low-level modulation
27471.
d. high-level modulation
27472.
18. If a superheterodyne receiver is tuned to a desired signal at 1000kHz and its
conversion (local) oscillator is operating at 1300kHz, what would be the frequency of an
incoming signal that would possibly cause image reception?
27473.
a. 1600 kHz
27474.
b. 2300 kHz
27475.
c. 1250 kHz
27476.
d. 3420 kHz
27477.
19. When modulation requires a much higher amplitude modulating signal to
achieve a reasonable percent modulation, this is called
27478.
a. high-level modulation
27479.
b. low-level modulation
27480.
c. zero-modulation
27481.
d. constant modulation
27482.
20. Amplitude modulators that vary the carrier amplitude with the modulating
signal by passing it through an attenuator work on principle of
27483.
a. rectification

27484.
b. resonance
27485.
c. variable resistance
27486.
d. absorption
27487.
21. A circuit which function is to raise the amplitude of the source signal to a
usable level while producing minimum nonlinear distortion adding as little thermal noise
as possible.
27488.
a. power amplifier
27489.
b. non-linear amplifier
27490.
c. buffer amplifier
27491.
d. preamplifier
27492.
22. A circuit that has a low-gain, high-input impedance linear amplifier which is
used to isolate the oscillator from the high-power amplifiers.
27493.
a. power amplifier
27494.
b. bandpass filter
27495.
c. signal driver
27496.
d. buffer amplifier
27497.
23. With high-level transmitters, which of the following is not a primary function
of the modulator circuit?
27498.
a. it provides the capacity necessary for modulation to occur
27499.
b. it serves as a final amplifier
27500.
c. it serves as a frequency up-converter
27501.
d. it serves as a mixer
27502.
24. It is a form of amplitude distortion introduced when positive and negative
alternations in the AM modulated signal are not equal.
27503.
a. phase shift
27504.
b. carrier shift
27505.
c. amplitude variations
27506.
d. frequency shift
27507.
25. A carrier is simultaneously modulated by two sine waves with modulation
indices of 0.3 and 0.4, the total modulation index
27508.
a. is 1
27509.
b. cannot be calculated unless the phase relations are known
27510.
c. is 0.5
27511.
d. is 0.7
27512.
26. The component used to produce AM AT very high frequencies is a
27513.
a. varactor
27514.
b. thermistor
27515.
c. cavity resonator
27516.
d. PIN diode
27517.
27. It is also known as upward modulation
27518.
a. carrier shift
27519.
b. amplitude variations
27520.
c. frequency shift
27521.
d. phase shift
27522.
28. Also known as downward modulation
27523.
a. carrier shift

27524.
b. amplitude variations
27525.
c. frequency shift
27526.
d. phase shift
27527.
29. It is a form of amplitude modulation where signals from two separate
information sources modulate the same carrier frequency at the same time without
interfering with each other.
27528.
a. QPSK
27529.
b. QUAM
27530.
c. PSK
27531.
d. FSK
27532.
30. A receiver has a dynamic range of 81 dB. It has 0.55nW sensitivity. Determine
the maximum allowable input signal.
27533.
a. 59 mW
27534.
b. 69 mW
27535.
c. 79 mW
27536.
d. 88 mW
27537.
31. The information sources modulate the same carrier after it has been separated
into two carrier signals are at 90 degrees out of phase with each other.
27538.
a. QPSK
27539.
b. QUAM
27540.
c. PSK
27541.
d. FSK
27542.
32. Demodulating quadrature AM signal requires a carrier recovery circuit to
reproduce the original carrier frequency and phase and two balanced modulators to
actually demodulate the signals. This is called ________.
27543.
a. asynchronous detection
27544.
b. quadrature demodulation
27545.
c. synchronous detection
27546.
d. quadrature detection
27547.
33. Quadrature amplitude modulation is also known as ________.
27548.
a. phase division multiplexing
27549.
b. phase division modulation
27550.
c. phase amplitude multiplexing
27551.
d. phase angle modulation
27552.
34. Amplitude modulation generated at a very low voltage or power amplitude is
known as
27553.
a. high-level modulation
27554.
b. low-level modulation
27555.
c. collector modulation
27556.
d. minimum modulation
27557.
35. It is the first stage of the receiver and is therefore often called the receiver
front end.
27558.
a. mixer
27559.
b. RF section
27560.
c. local oscillator
27561.
d. IF stage

27562.
36. In an SSB transmitter, one is most likely to find a
27563.
a. class C audio amplifier
27564.
b. tuned modulator
27565.
c. class B RF amplifier
27566.
d. class A RF output amplifier
27567.
37. The section of the receiver than down-converts the received RF frequencies to
intermediate frequencies.
27568.
a. RF section
27569.
b. local oscillator
27570.
c. power amplifier
27571.
d. mixer
27572.
38. The circuit that demodulates the AM wave and converts it to the original
information signal.
27573.
a. power amplifier
27574.
b. local oscillator
27575.
c. detector
27576.
d. IF section
27577.
39. A collector modulator has a supply voltage of 48V. The peak-to-peak
amplitude of the modulating signal for 100 percent modulation is
27578.
a. 24V
27579.
b. 48V
27580.
c. 96V
27581.
d. 120V
27582.
41. The noise reduction ratio achieved by reducing the bandwidth is called
27583.
a. dynamic range
27584.
b. noise figure
27585.
c. bandwidth efficiency
27586.
d. bandwidth improvement
27587.
42. It is the minimum RF signal level that can be detected at the input to the
receiver and still produce a usable demodulated information signal.
27588.
a. selectivity
27589.
b. sensitivity
27590.
c. Q-factor
27591.
d. bandwidth
27592.
43. For ideal AM, which of the following is true
27593.
a. m = 0
27594.
b. m = 1
27595.
c. m < 1
27596.
d. m > 1
27597.
46. It is defined as the difference in decibels between the minimum input level
necessary to discern the signal and the input level that will overdrive the receiver and
produce distortion.
27598.
a. dynamic range
27599.
b. noise figure
27600.
c. bandwidth efficiency
27601.
d. bandwidth improvement

27602.
47. It is the input power range over which the receiver is useful.
27603.
a. dynamic range
27604.
b. noise figure
27605.
c. bandwidth efficiency
27606.
d. bandwidth improvement
27607.
48. It is defined as the output power when the RF amplifier response is 1-dB less
than the ideal linear gain response.
27608.
a. 1-dB compression point
27609.
b. 1-dB threshold point
27610.
c. 1-dB shoot-off point
27611.
d. 1-dB pinch-off point
27612.
49. It is the measure of the ability of a communications system to produce, at the
output of the receiver, an exact replica of the original source information.
27613.
a. sensitivity
27614.
b. threshold
27615.
c. selectivity
27616.
d. fidelity
27617.
50. A SSB signal generated around a 200-kHz carrier. Before filtering, the upper
and lower sidebands are separated by 200 Hz. Calculate the filter Q required to obtain 40dB suppression.
27618.
a. 1500
27619.
b. 1900
27620.
c. 2500
27621.
d. 2000
27622.
51. The predominant cause of phase distortion.
27623.
a. overmodulation
27624.
b. buffering
27625.
c. filtering
27626.
d. clipping
27627.
52. It is the total phase shift encountered by a signal and can generally be
tolerated as long as all frequencies undergo the same amount of phase delay.
27628.
a. differential phase shift
27629.
b. absolute phase shift
27630.
c. relative phase shift
27631.
d. integrated phase shift
27632.
53. ________ occurs when different frequencies undergo different phase shifts
and may have a detrimental effect on the complex waveform.
27633.
a. differential phase shift
27634.
b. absolute phase shift
27635.
c. relative phase shift
27636.
d. integrated phase shift
27637.
54. What is the minimum AM signal needed to transmit information
27638.
a. carrier plus sidebands
27639.
b. carrier only
27640.
c. one sideband
27641.
d. both sidebands

27642.
55. The circuit that recovers the original modulating information from an AM
signal is known as a
27643.
a. modulator
27644.
b. demodulator
27645.
c. mixer
27646.
d. crystal set
27647.
56. __________ occurs when the amplitude-versus-frequency characteristics of a
signal at the output of a receiver cover from those in the original information signal.
27648.
a. frequency distortion
27649.
b. digital distortion
27650.
c. phase distortion
27651.
d. amplitude distortion
27652.
57. The circuit used to produced modulations called
27653.
a. modulator
27654.
b. demodulator
27655.
c. variable gain amplifier
27656.
d. multiplexer
27657.
58. It is the result pf non-uniform gain in amplifiers and filters.
27658.
a. harmonic distortion
27659.
b. amplitude distortion
27660.
c. frequency distortion
27661.
d. phase distortion
27662.
59. It is a result of harmonic and intermodulation distortion and is caused by nonlinear amplification.
27663.
a. amplitude distortion
27664.
b. phase distortion
27665.
c. harmonic distortion
27666.
d. frequency distortion
27667.
60. The most commonly used amplitude demodulator is the
27668.
a. diode mixer
27669.
b. balanced modulator
27670.
c. envelope detector
27671.
d. crystal filter
27672.
61. It is a special case of intermodulation distortion and a predominant cause of
frequency distortion.
27673.
a. second-order intercept distortion
27674.
b. phase distortion
27675.
c. third-order intercept distortion
27676.
d. first-order intercept distortion
27677.
62. A display of signal amplitude versus frequency is called the
27678.
a. time domain
27679.
b. frequency spectrum
27680.
c. amplitude modulation
27681.
d. frequency domain
27682.
63. It is a parameter associated with frequencies that fall within the passband of
the filter.

27683.
a. coupling loss
27684.
b. diffusion loss
27685.
c. insertion loss
27686.
d. filter loss
27687.
64. A circuit that generates the upper and lower sidebands but no carrier is called
27688.
a. amplitude modulator
27689.
b. diode detector
27690.
c. class C amplifier
27691.
d. balanced modulator
27692.
65. Vestigial sideband modulation (C3F) is normally used for
27693.
a. HF point-to-point communications
27694.
b. monaural broadcasting
27695.
c. TV broadcasting
27696.
d. stereo broadcasting
27697.
66. It is generally defined as the ratio of the power transferred to a load with a
filter in the circuit to the power transferred to a load without a filter.
27698.
a. distortion loss
27699.
b. insertion loss
27700.
c. filter loss
27701.
d. harmonic loss
27702.
67. The modulation index of an AM wave is changed from 0 to 1. The transmitted
power is
27703.
a. unchanged
27704.
b. halved
27705.
c. doubled
27706.
d. increased by 50 percent
27707.
68. The inputs to a balanced modulator are 1MHz and a carrier of 1.5 MHz. The
outputs are
27708.
a. 500kHz and 1.5MHz
27709.
b. 2.5MHz and 1.5MHz
27710.
c. 1.5MHz and 500kHz
27711.
d. 500kHz and 2.5MHz
27712.
69. It is an indication of the reduction the signal-to-noise ration as a signal
propagates through the receiver.
27713.
a. noise figure
27714.
b. equivalent noise temperature
27715.
c. noise factor
27716.
d. signal-to-noise ratio
27717.
70. Types of receivers where the frequencies generated in the receiver and used
for demodulation are synchronized to oscillator frequencies generated in the transmitter.
27718.
a. coherent
27719.
b. asynchronous
27720.
c. non-coherent
27721.
d. none of these
27722.
71. Types of receiver where either no frequencies are generated in the receiver of
the frequencies used for demodulation are completely independent form the transmitter's

carrier frequency.
27723.
a. synchronous
27724.
b. coherent
27725.
c. asynchronous
27726.
d. any of these
27727.
72. A widely used balanced modulator is called the ________.
27728.
a. diode bridge circuit
27729.
b. full-wave bridge rectifier
27730.
c. lattice modulator
27731.
d. balanced bridge modulator
27732.
73. Non-coherent detection is also known as ________.
27733.
a. frequency detection
27734.
b. noise detection
27735.
c. phase detection
27736.
d. envelope detection
27737.
74. It is one of the earliest type of AM receiver
27738.
a. TRF
27739.
b. transistorized
27740.
c. superhet
27741.
d. Armstrong
27742.
75. Which of the following is not true about the disadvantages of tuned radio
frequency receiver?
27743.
a. their bandwidth is inconsistent and varies with center frequency when
tuned over a wide range of input frequencies
27744.
b. it is unstable due to the large number of RF amplifiers all tuned to the
same center frequency
27745.
c. their gains are not uniform over a very wide frequency range
27746.
d. it is very complex to construct
27747.
76. In a diode ring modulator, the diode acts like
27748.
a. variable resistors
27749.
b. switches
27750.
c. rectifiers
27751.
d. variable capacitors
27752.
77. It means to mix two frequencies together in a non-linear device or to translate
on frequency to another using non-linear mixing.
27753.
a. oscillation
27754.
b. heterodyne
27755.
c. modulation
27756.
d. amplification
27757.
78. An AM transmitter antenna current is measured with no modulation and found
to be 2.6 amperes. With modulation, the current rises to 2.9 amperes. The percentage
modulation is
27758.
a. 35%
27759.
b. 70%
27760.
c. 42%
27761.
d. 89%

27762.
79. Its primary purpose is to provide enough initial bandlimiting to prevent a
specific unwanted radio frequency from entering the receiver.
27763.
a. detector
27764.
b. predetector
27765.
c. preselector
27766.
d. mixer
27767.
80. It function is to reduce the noise bandwidth of the receiver and provides initial
step
27768.
toward reducing the overall receiver bandwidth to the minimum bandwidth
required to pass the information signals.
27769.
a. preselector
27770.
b. detector
27771.
c. mixer
27772.
d. predetector
27773.
81. The output of a balanced modulator is
27774.
a. AM
27775.
b. FM
27776.
c. SSB
27777.
d. DSB
27778.
82. What is the first active device encountered by the received signal in the
receiver?
27779.
a. mixer
27780.
b. RF amplifier
27781.
c. local oscillator
27782.
d. detector
27783.
83. The IF section is also known as
27784.
a. bandpass filters
27785.
b. IF strip
27786.
c. IF filter
27787.
d. intermediate filters
27788.
84. The detector in an AM receiver is known as
27789.
a. audio detector
27790.
b. power detector
27791.
c. first detector
27792.
d. amplitude limiter
27793.
85. A carrier of 880kHz is modulated by a 3.5 kHz sine wave. The LSB and USB
are, respectively
27794.
a. 873 and 887kHz
27795.
b. 876.5 and 883.5kHz
27796.
c. 883.5 and 876.5kHz
27797.
d. 887 and 873kHz
27798.
86. The most commonly used filter in SSB generators uses
27799.
a. LC networks
27800.
b. mechanical resonators
27801.
c. crystals
27802.
d. RC networks and op-amps

27803.
87. Its purpose of the detector section is to convert the IF signals back to the
original source information.
27804.
a. mixer
27805.
b. audio amplifier
27806.
c. converter
27807.
d. detector
27808.
88. It means that the two adjustments are mechanically tied together so that a
single adjustment will change the center frequency of the preselector, at the same time,
change the oscillator frequency.
27809.
a. high-side injecting
27810.
b. low-side injecting
27811.
c. gang tuning
27812.
d. local oscillator tracking
27813.
89. In a low-level AM system, amplifiers following the modulated stage must be
27814.
a. linear devices
27815.
b. harmonic devices
27816.
c. class C amplifiers
27817.
d. nonlinear devices
27818.
90. When the local oscillator is tuned above the radio frequency, it is called
27819.
a. local oscillator tracking
27820.
b. low-side injection
27821.
c. gang tuning
27822.
d. high-side injection
27823.
91. The equivalent circuit of a quartz us a
27824.
a. series resonant circuit
27825.
b. parallel resonant circuit
27826.
c. none of these
27827.
d. series and parallel resonant circuit
27828.
92. It is the ability of the local oscillator in a receiver to oscillate either above or
below the selected radio frequency carrier by an amount equal to the intermediate
frequency throughout the entire radio frequency brand.
27829.
a. tracking
27830.
b. mixing
27831.
c. heterodyning
27832.
d. tuning
27833.
93. The difference between the actual local oscillator frequency and the desired
frequency is called ________.
27834.
a. mixing error
27835.
b. gang error
27836.
c. tracking error
27837.
d. quantizing error
27838.
94. What technique is used to prevent tracking error?
27839.
a. using RLC circuit
27840.
b. using tuned circuit
27841.
c. using three-point tracking
27842.
d. using ganged capacitors

27843.
95. a crystal lattice filter has a crystal frequencies pf 27.5 and 27.502MHz. The
bandwidth is approximately
27844.
a. 2kHz
27845.
b. 3kHz
27846.
c. 27.501MHz
27847.
d. 55.502MHz
27848.
96. ___________ is any frequency other than selected radio frequency carrier
that, if allowed to enter a receiver and mix it with local oscillator, will produce a crossproduct frequency that is equal to the intermediate frequency
27849.
a. image frequency
27850.
b. intermediate frequency
27851.
c. aliasing frequency
27852.
d. ghost
27853.
97. It is a equivalent to a second radio frequency that will produce an IF that will
interfere with the IF from the desired radio frequency.
27854.
a. aliasing frequency
27855.
b. image frequency
27856.
c. interference
27857.
d. intermediate frequency
27858.
98. An SSB generator has a sideband filter centered at 3.0MHz. The modulating
signal is 3kHz. To produce both upper and lower sidebands, the following carrier
frequencies must be produced:
27859.
a. 2.7 and 3.3MHz
27860.
b. 3.3 and 3.6MHz
27861.
c. 2997 and 3003kHz
27862.
d. 3000 and 3003kHz
27863.
99. It is a numerical measure of the ability of the preselector to reject the image
frequency.
27864.
a. image frequency rejection ratio
27865.
b. noise figure
27866.
c. numerical aperture
27867.
d. signal-to-noise ratio
27868.
100. _________ occurs when a receiver picks up the same station at two nearby
points on the receiver tuning dial.
27869.
a. spurious pointing
27870.
b. under coupling
27871.
c. double spotting
27872.
d. optimal coupling
27873.
101. In the phasing method of SSB generation, one sideband is cancelled due out
to
27874.
a. phase shift
27875.
b. sharp selectivity
27876.
c. carrier suppression
27877.
d. phase inversion
27878.
102. It is caused by poor front-end selectivity or inadequate image frequency
rejection.

27879.
a. optimal coupling
27880.
b. double spotting
27881.
c. spurious pointing
27882.
d. under coupling
27883.
103. It is a high-gain, low noise, tuned amplifier that, when used is the first active
encountered by the receiver signal.
27884.
a. mixer
27885.
b. local oscillator
27886.
c. RF amplifier
27887.
d. detector
27888.
104. It is a high performance microwave receiver at the input stage. In the RF
section of optimize their noise figure.
27889.
a. high-power amplifier
27890.
b. low noise amplifier
27891.
c. buffer amplifier
27892.
d. local oscillator
27893.
105. A balanced modulator used to demodulates a SSB signal is called
27894.
a. transponder
27895.
b. product detector
27896.
c. converter
27897.
d. modulator
27898.
106. Which of the following is not the other name of a balanced modulator?
27899.
a. balanced mixer
27900.
b. product detector
27901.
c. product modulator
27902.
d. none of these
27903.
107. ________ amplifiers are relatively high gain tuned amplifiers that are very
similar to RF amplifiers, except that it operates over a relatively narrow, fixed frequency
band.
27904.
a. IF amplifiers
27905.
b. low-noise amplifiers
27906.
c. buffer amplifiers
27907.
d. high-power amplifier
27908.
108. Type of tuned circuit where both the primary and secondary sides of the
transformer are tuned tank circuits
27909.
a. RLC tuned circuit
27910.
b. double-tuned circuit
27911.
c. single-tuned circuit
27912.
d. LC tuned circuit
27913.
109. Frequency translation is done with a circuit called _______.
27914.
a. summer
27915.
b. multiplier
27916.
c. filter
27917.
d. mixer
27918.
110. Low noise RF amplifiers use what type biasing?
27919.
a. class A

27920.
b. class B
27921.
c. class AB
27922.
d. class C
27923.
111. Its purpose is to down-convert the incoming radio frequencies to
intermediated frequencies.
27924.
a. local oscillator
27925.
b. RF amplifier
27926.
c. detector
27927.
d. mixer
27928.
112. It is a non-linear amplifier similar to modulator, except that the output is
turned to different between the RF and local oscillator frequencies.
27929.
a. RF amplifier
27930.
b. local oscillator
27931.
c. mixer
27932.
d. detector
27933.
113. Mixing for frequency conversion is the same as
27934.
a. rectification
27935.
b. AM
27936.
c. linear summing
27937.
d. filtering
27938.
114. The most common technique used for coupling IF amplifiers
27939.
a. resistive coupling
27940.
b. inductive coupling
27941.
c. capacitive coupling
27942.
d. direct coupling
27943.
115. When the modulation index of an AM wave doubled, the antenna current is
also doubled. The AM system being used is
27944.
a. single-sideband, full carrier (H3E)
27945.
b. vestigial sideband (C3F)
c. single sideband, suppressed carrier (J3E)
27946.
d. double sideband, full carrier (A3E)
27947.
116. The ability of a coil to induce a voltage within its own windings is called
27948.
a. mutual inductance
27949.
b. coefficient coupling
27950.
c. self- inductance
27951.
d. inductance
27952.
117. If the carrier of a 100 percent modulated AM wave is suppressed the
precentage power saving will be
27953.
a. 50
27954.
b. 150
27955.
c. 100
27956.
d. 66.66
27957.
118. The ability of one coil to induce a voltage in another coil is called
_________.
27958.
a. coefficient coupling
27959.
b. mutual inductance

27960.
c. inductance
27961.
d. self-inductance
27962.
119. Which of the following cam be used as a mixer?
27963.
a. balanced modulator
27964.
b. FET
27965.
c. diode modulator
27966.
d. all of the above
27967.
120. It is the ratio of the secondary flux to primary flux
27968.
a. Q factor
27969.
b. coefficient coupling
27970.
c. self-inductance
27971.
d. coefficient of modulation
27972.
121. Type of coupling where the secondary voltage is relatively low and the
bandwidth is narrow.
27973.
a. tight coupling
27974.
b. optimum coupling
27975.
c. loose coupling
27976.
d. critical coupling
27977.
122. An AM signal, transmitted information is contained within the
27978.
a. carrier
27979.
b. modulating signal
27980.
c. sidebands
27981.
d. envelope
27982.
123. Typer of coupling which has high gain and a broad bandwidth
27983.
a. optimum coupling
27984.
b. tight coupling
27985.
c. double coupling
27986.
d. loose coupling
27987.
124. It is the point where the reflected resistance is equal to primary resistance
and the Q of the primary tank circuit is halved and the bandwidth doubled.
27988.
a. critical coupling
27989.
b. tight coupling
27990.
c. loose coupling
27991.
d. optimum coupling
27992.
125. The desired output from a mixer is usually selected with a
27993.
a. phase-shift circuit
27994.
b. crystal filter
27995.
c. resonant circuit
27996.
d. transformer
27997.
126. It is caused by the reactive element of the reflected impedance being
significant enough to change the resonant frequency of the primary tuned circuit.
27998.
a. optimum coupling
27999.
b. critical coupling
28000.
c. double peaking
28001.
d. flux linkage
28002.
127. IF transformers come as specially designed tuned circuits in groundable

metal packages called _______.
28003.
a. IF cans
28004.
b. IF container
28005.
c. IF strip
28006.
d. IF tetrapack
28007.
128. The AM detector is sometimes called _______.
28008.
a. first detector
28009.
b. third detector
28010.
c. second detector
28011.
d. fourth detector
28012.
129. The mixer is sometimes called _________.
28013.
a. first detector
28014.
b. third detector
28015.
c. second detector
28016.
d. fourth detector
28017.
130. The two inputs to a mixer are the signal to be translated and a signal from
28018.
a. modulator
28019.
b. filter
28020.
c. antenna
28021.
d. local oscillator
28022.
131. AM demodulator is commonly called _________.
28023.
a. phase detector
28024.
b. peak detector
28025.
c. frequency detector
28026.
d. transistor detector
28027.
132. A type of detector that detects the shape of the input envelope
28028.
a. peak detector
28029.
b. phase detector
28030.
c. diode detector
28031.
d. shape detector
28032.
133. The ratio of the peak modulating signal voltage to the peak carrier voltage is
referred to as
28033.
a. voltage ratio
28034.
b. decibels
28035.
c. modulation index
28036.
d. mix factor
28037.
134. A circuit that automatically increases the receiver gain for weak RF input
levels and automatically decreases the receiver gain when a strong RF signal is received.
28038.
a. automatic volume control
28039.
b. automatic frequency control
28040.
c. automatic gain control
28041.
d. automatic phase control
28042.
135. Which is not a type of AGC?
28043.
a. simple AGC
28044.
b. forward AGC
28045.
c. delayed AGC

28046.
d. complex AGC
28047.
136. The value Vmax and Vmin as read from AM wave on an oscilloscope are 3.0
and 2.8. The percentage of modulation is
28048.
a. 10 percent
28049.
b. 41.4 percent
28050.
c. 80.6 percent
28051.
d. 93.3 percent
28052.
137. Amplitude modulation is used for broadcasting because
28053.
a. it is more noise immune than other modulation systems
28054.
b. compared to other systems it requires less transmitting power
28055.
c. its use avoids receiver complexity
28056.
d. no other modulation system can provide the necessary bandwidth for
high fidelity
28057.
138. Type of AGC that prevents the AGC feedback voltage from reaching the RF
or IF amplifiers until the RF level exceeds a predetermined magnitude.
28058.
a. forward AGC
28059.
b. delayed AGC
28060.
c. complex AGC
28061.
d. simple AGC
28062.
139. A circuit with a purpose to quiet a receiver in the absence of a received
signal.
28063.
a. automatic gain control
28064.
b. automatic frequency control
28065.
c. squelch circuit
28066.
d. automatic volume control
28067.
140. A section of a audio stage of a receiver that removes sporadic, high
amplitude noise transients of short duration, such as impulse noise.
28068.
a. squelch circuit
28069.
b. clampers
28070.
c. clippers
28071.
d. peak detector
28072.
141. A circuit that detects the occurrence of a high-amplitude, short duration noise
spike then mutes the receiver by shutting off a portion of the receiver of the duration of
the pulse.
28073.
a. squelch circuit
28074.
b. limiter
28075.
c. clamper
28076.
d. blanking circuit
28077.
142. The opposite modulation is
28078.
a. reverse modulation
28079.
b. downward modulation
28080.
c. unmodulation
28081.
d. demodulation
28082.
143. For good imag-frequency rejection, what is the desired value of the
intermediate frequency?
28083.
a. relatively low IF

28084.
b. very low IF
28085.
c. relatively high IF
28086.
d. very high IF
28087.
144. With high-gain selective amplifiers that are stable and easily neutralized.
what is the desired value of intermediate frequency?
28088.
a. low IF
28089.
b. medium IF
28090.
c. high IF
28091.
d. very high IF
28092.
145. It is defined as the ratio of the demodulated signal level at the output receiver
to the RF signal level at the input to the receiver.
28093.
a. received signal level
28094.
b. figure of merit
28095.
c. effective radiated power
28096.
d. net receiver gain
28097.
146. It is the process of modifying the characteristic of one signal in accordance
with some characteristic of another signal.
28098.
a. multiplexing
28099.
b. mixing
28100.
c. modulation
28101.
d. summing
28102.
147. The imaginary line on the carrier waveform of the amplitude modulated
signal is called __________.
28103.
a. sidebands
28104.
b. envelope
28105.
c. spurious emission
28106.
d. information
28107.
148. Indicate the false statement regarding the advantages of the phase
cancellation method of obtaining SSB over the filter method is false:
28108.
a. more channel space available
28109.
b. transmitter circuits must be stable, giving better spectrum
28110.
c. the signal is more noise resistant
28111.
d. much less power is required for the same signal strength
28112.
149. Indicate which one of the following advantages of the phase cancellation
method of obtaining SSB over the filter method is false:
28113.
a. switching from one sideband to the other simpler
28114.
b. it is possible to generated SSB at any frequency
28115.
c. SSB with lower audio frequencies present can be generated.
28116.
d. There are more balanced modulators, therefore the carrier is
suppressed better
28117.
150. The most commonly used filters is SSB generation are
28118.
a. mechanical
28119.
b. RC
28120.
c. LC
28121.
d. low-pass
28122.
152.One of the following cannot be used to remove the unwanted sideband in

SSB. This is the
28123.
a. filter system
28124.
b. phase-shift method
28125.
c. third method
28126.
d. balanced modulator
28127.
153. R3E modulation is sometimes used to
28128.
a. allow the receiver to have a frequency synthesizer
28129.
b. simplify the frequency stability problem in reception
28130.
c. reduce the power that must be transmitted
28131.
d. reduce the bandwidth required for transmission
28132.
154. To provide two or more voice circuits with the same carrier, it is necessary to
use
28133.
a. ISB
28134.
b. carrier reinsertion
28135.
c. SSB with pilot carrier
28136.
d. Lincomplex
28137.
155. A type of AGC is similar to conventional AGC except that the receive signal
is monitored closer to the front end of the receiver and the correction voltage is fed
forward to the IF amplifiers
28138.
a. ISB
28139.
b. delayed AGC
28140.
c. complex AGC
28141.
d. simple AGC
28142.
156. Having an information signal change some characteristics of a carrier signal
is called
28143.
a. multiplexing
28144.
b. modulation
28145.
c. duplexing
28146.
d. linear mixing
28147.
157. A circuit that compensates for minor variations in the received RF signal
level
28148.
a. automatic volume control
28149.
b. automatic frequency control
28150.
c. automatic gain control
28151.
d. automatic phase control
28152.
158. Which of the following is not true about AM?
28153.
a. the carrier amplitude varies
28154.
b. the carrier frequency remains constant
28155.
c. the carrier frequency changes
28156.
d. the information signal amplitude changes the carrier amplitude
28157.
159. A modulator circuit performs what mathematical operation on its two inputs?
28158.
a. addition
28159.
b. multiplication
28160.
c. division
28161.
d. square root
28162.
160. If m is greater than 1, what happens?

28163.
a. normal operation
28164.
b. carrier drops to 0
28165.
c. information signal is distorted
28166.
161. The outline of the peaks of a carrier has the shape of modulating signal and is
called _______.
28167.
a. trace
28168.
b. wave shape
28169.
c. envelope
28170.
d. carrier variation
28171.
162. Overmodulation occurs when
28172.
a. Vm > Vc
28173.
b. Vm < Vc
28174.
c. Vm = Vc
28175.
d. Vm = Vc = 0
28176.
163. The new signal produced by modulation are called __________.
28177.
a. spurious emission
28178.
b. harmonics
28179.
c. intermodulation products
28180.
d. sidebands
28181.
164. An AM signal has a carrier power of 5W, the percentage of modulation is 80
pecent. The total power sideband is _________.
28182.
a. 0.8 W
28183.
b. 1.6 W
28184.
c. 2.5 W
28185.
d. 4.0 W
28186.
165. For 100 percent modulation, what percentage of power is in each sideband
28187.
a. 25 percent
28188.
b. 33.3 percent
28189.
c. 50 percent
28190.
`
d. 100 percent
28191.
166. An AM transmitter has a percentage of modulation of 88, the carrier power is
440 W. The power in one sideband is
28192.
a. 85 W
28193.
b. 110 W
28194.
c. 170 W
28195.
d. 610 W
28196.
167. An AM signal without the carrier is called ______.
28197.
a. SSB
28198.
b. vestigial sidebands
28199.
c. FM signal
28200.
d. DSB
28201.
168. It is a form of amplitude modulation in which the carrier is transmitted at full
power, but only one of the sidebands is transmitted.
28202.
a. SSBFC
28203.
b. SSBSC
28204.
c. SSBRC

28205.
d. ISB
28206.
169. With single-sideband full carrier, 100% modulation would mean a carrier
power of how many percent of the total transmitted power?
28207.
a. 80%
28208.
b. 20%
28209.
c. 50%
28210.
d. 40%
28211.
170. It is a form of amplitude modulation in which the carrier is suppressed and
one of the sidebands removed
28212.
a. SSBFC
28213.
b. ISB
28214.
c. vestigial sideband
28215.
d. SSBSC
28216.
171. It is a form of amplitude modulation in which one sideband is totally
removed and the carrier voltage is reduced to approximately 10% of its unmodulated
amplitude
28217.
a. inderpendent sideband
28218.
b. SSBFC
28219.
c. SSBRC
28220.
d. SSBSC
28221.
172. It is a form of amplitude modulation in which a single carrier frequency is
independently modulated by two different modulating signal.
28222.
a. vestigial sideband
28223.
b. DSBFC
28224.
c. independent sideband
28225.
d. SSBFC
28226.
173. It is a form of amplitude modulation in which the carrier and one complete
sideband are transmitted, but only part of the second sideband is transmitted.
28227.
a. independent sideband
28228.
b. vestigial sideband
28229.
c. DSBFC
28230.
d. SSBSC
28231.
174. It is the rms power developed at the crest of the modulation envelope of
SSBSC.
28232.
a. carrier power
28233.
b. total transmitted power
28234.
c. sideband power
28235.
d. peak envelope power
28236.
175. Which of the following is not true about single-sideband transmission?
28237.
a. power is conserved
28238.
b. selective fading is eliminated
28239.
c. bandwidth is conserved
28240.
d. tuning is easy
28241.
176.A circuit that produces a double sideband suppressed carrier signal is called
____________.
28242.
a. filter

28243.
b. mixer
28244.
c. demodulator
28245.
d. balanced modulator
28246.
177. A balanced modulator is sometimes called _________.
28247.
a. balanced ring modulator
28248.
b. balanced resistor modulator
28249.
c. balanced lattice modulator
28250.
d. any of these
28251.
178. A type of filter that receives electrical energy, converts it to mechanical
vibrations and then converts the vibrations back to electrical energy at its output.
28252.
a. crystal filter
28253.
b. mechanical filter
28254.
c. LC filter
28255.
d. SAW filter
28256.
179. A type of filter that uses acoustic energy rather than electromechanical
energy to provide excellent performance for precise bandpass filtering.
28257.
a. SAW filter
28258.
b. RC filter
28259.
c. mechanical filter
28260.
d. crystal filter
28261.
180. The difference between the IF and the BFO frequencies is called _________.
28262.
a. information signal
28263.
b. beat frequency
28264.
c. carrier signal
28265.
d. heterodyned signal
28266.
181. It is a circuit which is a narrowband PLL that tracks the pilot carrier in the
composite SSBRC receiver signal and uses the recovered carrier to regenerate coherent
local oscillator frequencies in the synthesizer.
28267.
a. beat frequency oscillator
28268.
b. mechanical filter
28269.
c. local oscillator
28270.
d. carrier recovery circuit
28271.
182. A system that provides narrowband voice communications for land mobile
services with nearly the quality achieved with FM systems and do it using less than onethird the bandwidth.
28272.
a. SSBSC
28273.
b. DSBFC
28274.
c. ACSSB
28275.
d. SSBAC
28276.
183. It is a process of combining transmissions from more than one source and
transmitting them over a common facility such as metallic or optical fiber cable or a
radio-frequency channel.
28277.
a. buffering
28278.
b. modulation
28279.
c. multiplexing
28280.
d. demultiplexing

28281.
184. It is an analog method of combining two or more analog sources that
originally occupied the same frequency band in such a manner that the channels do not
interfere with each other.
28282.
a. ATM
28283.
b. FDM
28284.
c. TDM
28285.
d. WDM
28286.
185. It is a multiplexing method that uses double-sideband suppressed-carrier
transmission to combine two information sources into a single composite waveform.
28287.
a. QM
28288.
b. WDM
28289.
c. TDM
28290.
d. FDM
28291.
186. Single-sideband transmitters are rated in _________.
28292.
a. rms power
28293.
b. dc power
28294.
c. average power
28295.
d. peak envelope power
28296.
187. In an SSB transmitter, one is most likely to find a __________.
28297.
a. class C audio amplifier
28298.
b. tuned modulator
28299.
c. class B RF amplifier
28300.
d. class A RF output amplifier
28301.
188. Indicate in which one of the following only one sideband is transmitted:
28302.
a. H3E
28303.
b. A3E
28304.
c. B8E
28305.
d. C3F
28306.
189. One of the following cannot be used to remove the unwanted sideband in
SSB. This is the
28307.
a. filter system
28308.
b. phase-shift method
28309.
c. third method
28310.
d. balanced modulator
28311.
190. R3E modulation is sometimes used to
28312.
a. allow the receiver to have a frequency synthesizer
28313.
b. simplify the frequency stability problem in reception
28314.
c. reduce the power that must be transmitted
28315.
d. reduce the bandwidth required for transmission
28316.
191. To provide two or more voice circuits with the same carrier, it is necessary to
use
28317.
a. ISB
28318.
b. carrier reinsertion
28319.
c. SSB with pilot carrier
28320.
d. Lincomplex
28321.
192. The main advantage of SSB over standard AM or DSB is

28322.
a. less spectrum is used
28323.
b. simpler equipment is used
28324.
c. less power is consumed
28325.
d. a higher modulation percentage
28326.
193. In SSB, which sideband is the best to use?
28327.
a. upper
28328.
b. lower
28329.
c. neither
28330.
d. depends upon the use
28331.
194. The output of an SSB transmitter with a 3.85 MHz carrier and a 1.5 kHz sine
wave modulating tone is
28332.
a. a 3.8485 MHz sine wave
28333.
b. a 3.85 MHz sine wave
28334.
c. 3.85, 3.8485 and 3.8515 MHz sine waves
28335.
d. 3848.5 and 3851.5 MHz sine waves
28336.
195. An SSB transmitter produces a 400 V peak to peak signal across a 52 ohm
antenna load. The PEP output is
28337.
a. 192.2 W
28338.
b. 384.5 W
28339.
c. 769.2 W
28340.
d. 3077 W
28341.
196. The output power of SSB transmitter is usually expressed is terms of
28342. a. average power
28343.
b. RMS power
28344.
c. peak to peak power
28345.
d. peak envelope power
28346.
197. An SSB transmitter has a PEP rating of 1 kilowatts. The average output
power is in the range of
28347.
a. 150 to 450 W
28348.
b. 100 to 300 W
28349.
c. 250 to 333 W
28350.
d. 3 to 4 kW
28351.
198. In amplitude modulation technique, the unmodulated carrier is referred to as
having___..
28352.
a. 100% modulation
28353.
b. 0% modulation
28354.
c. 50% modulation
28355.
d. overmodulated
28356.
199. What is the process in radio communication where the information or
intelligent signal is at lower frequency is put unto higher radio frequency for transmission
to receiving station?
28357.
a. detection
28358.
b. mixing
28359.
c. modulation
28360.
d. demodulation
28361.
200. Which of the following signals is suppressed by balanced modulator circuit?

28362.
28363.
28364.
28365.

a. 1st IF signal
b. carrier signal
c. harmonics
d. 2nd IF signal
28366.
28367.
28368.
28369.
28370.
28371.
28372.
28373.
28374.
28375.
28376.

28377. MULTIPLE CHOICE QUESTIONS IN

28378. ANGLE
MODULATION
28379.

Electronics Systems and Technologies
28380. By
28381.

Melvin C. Arceo
28382.
28383.
28384.
28385.
28386.
28387.

28388.
28389.
28390.
28391.

28392. ENCODED BY:
28393. SANTOLLO, Dan Alvin
28394.
28395.
28396.
28397.
28398.

1. He developed the first successful FM radio system
a. B.E.Alpine
b. N.S. Kapany
c. E.H. Armstrong
d. A.C.S. Van Heel

28399.
2. Results whenever the phase angle of sinusoidal wave is varied with respect to
time
28400.
a. angle modulation
28401.
b. digital modulation
28402.
c. amplitude modulation
28403.
d. pulse modulation
28404.
3. In the spectrum of a frequency -modulated wave
28405.
a. the carrier frequency disappears with a large modulation index
28406.
b. the amplitude of any sideband depends on the modulation index
28407.
c. the total number of sidebands depends on the modulation index
28408.
d. the carrier frequency cannot disappear
28409.
4.What is the frequency swing of an FM broadcast transmitter when modulated
60%
28410.
a. 60 kHz
28411.
b. 45 kHz
28412.
c. 30 kHz
28413.
d. 25 kHz
28414.
5. Varying the frequency of a constant -amplitude carrier directly proportional to
the amplitude to the modulating signal at a rate equal to the frequency of the modulating
signal
28415.
a. amplitude modulation
28416.
b. angle modulation
28417.
c. phase modulation
28418.
d. frequency modulation
28419.
6. The amount of frequency deviation from the carrier center frequency in an FM
transmitter is proportional to what characteristic of the frequency signal?
28420.
a. amplitude
28421.
b. frequency
28422.
c. phase
28423.
d. shape
28424.
7. It is a modulation where the angle of a wave carrier is varied from its reference
value
28425.
a. amplitude modulation
28426.
b. angle modulation
28427.
c. analog modulation
28428.
d. digital modulation
28429.
8. Both FM and PM are types of what kind of modulation?
28430.
a. amplitude
28431.
b. phase
28432.
c. angle
28433.
d. duty cycle
28434.
9. Varying the phase of a constant amplitude carrier displacement proportional to
the amplitude of the modulating signal at a rate equal to the frequency of the modulating
signal.
28435.
a. amplitude modulation
28436.
b. angle modulation

28437.
c. phase modulation
28438.
d. frequency modulation
28439.
10. The difference between phase and frequency modulation
28440.
a. is purely theoretical because they are the same in practice
28441.
b. is too great to make the two systems compatible
28442.
c. lies in the poorer audio responses of phase modulation
28443.
d. lies in the different definitions of the modulation index
28444.
11. The relative angular displacement of the carrier phase in radians with respect
to the reference phase is called __________.
28445.
a. phase deviation
28446.
b. carrier deviation
28447.
c. frequency deviation
28448.
d. information deviation
28449.
12. If the amplitude of the modulating signal decreases, the carrier deviation
28450.
a. increases
28451.
b. decreases
28452.
c. remains constant
28453.
d. goes to zero
28454.
13. On an FM signal, maximum deviation occurs at what point on the modulating
signal?
28455.
a. zero-crossing points
28456.
b. peak positive amplitudes
28457.
c. peak negative amplitude
28458.
d. both peak positive and negative amplitudes
28459.
14. The amount of oscillator frequency increase and decrease around the carrier
frequency is called _________.
28460.
a. frequency deviation
28461.
b. phase shift
28462.
c. intelligence frequency
28463.
d. baseband
28464.
15. The relative displacement of the carrier frequency in hertz in respect to its
unmodulated value is called _____________.
28465.
a. frequency deviation
28466.
b. phase deviation
28467.
c. information deviation
28468.
d. carrier deviation
28469.
16. A pre-emphasis circuit provides extra noise immunity by
28470.
a. boosting the bass frequencies
28471.
b. amplifying the higher audio frequencies
28472.
c. preamplfying the whole audio band
28473.
d. converting the phase modulation to FM
28474.
17. It is the instantaneous change in phase of the carrier at a given instant of time
and indicates how much phase of the carrier is changing with respect to its reference
phase.
28475.
a. instantaneous frequency
28476.
b. instantaneous frequency deviation

28477.
c. instantaneous phase
28478.
d. instantaneous phase deviation
28479.
18. Calculate the amount of frequency deviation caused by a limited noise spike
that still cause an undesired phase shift of 35 degrees when the input frequency is 5kHz.
28480.
a. 2.40kHz
28481.
b. 3.05kHz
28482.
c. 1.29kHz
28483.
d. 4.45kHz
28484.
19. Which of the following determines the rate of carrier deviation?
28485.
a. intelligence frequency
28486.
b. frequency deviation
28487.
c. carrier frequency
28488.
d. broadband frequency
28489.
20. It is the precise phase of the carrier at a given instant of time
28490.
a. instantaneous phase deviation
28491.
b. instantaneous phase
28492.
c. instantaneous frequency deviation
28493.
d. instantaneous frequency
28494.
21. In PM, a frequency shift occurs while what characteristic of the modulating
signal is changing?
28495.
a. shape
28496.
b. phase
28497.
c. frequency
28498.
d. amplitude
28499.
22. In FM, it is a device that in which amplitude variations are derived in response
to frequency or phase variations
28500.
a. detector
28501.
b. discriminator
28502.
c. demodulator
28503.
d. receiver
28504.
23. Maximum frequency deviation of a PM signal occurs at
28505.
a. zero-crossing points
28506.
b. peak positive amplitudes
28507.
c. peak negative amplitude
28508.
d. peak positive and negative amplitude
28509.
24. Since noise phase-modulates the FM wave, as the noise sideband frequency
approaches the carrier frequency, the noise amplitude
28510.
a. remains constant
28511.
b. is decreased
28512.
c. is increased
28513.
d. is equalized
28514.
25. It is the instantaneous change in frequency of the carrier and is defined as the
first time derivative of the phase deviation
28515.
a. instantaneous frequency
28516.
b. instantaneous frequency deviation
28517.
c. instantaneous phase

28518.
d. instantaneous phase deviation
28519.
26. Since noise phase- modulates the FM wave, as the noise sideband frequency
approaches the carrier frequency, the noise amplitude
28520.
a. remains constant
28521.
b. is decreased
28522.
c. is increased
28523.
d. is equalized
28524.
27. It is the precise frequency of the carrier at a given instant of time is defined as
the first time derivative of the instantaneous phase.
28525.
a. instantaneous frequency
28526.
b. instantaneous frequency deviation
28527.
c. instantaneous phase
28528.
d. instantaneous phase deviation
28529.
28. It is the output-versus-input transfer functions for modulators which give the
relationship between the output parameter changes in respect to specified changes in the
input signal.
28530.
a. frequency deviation
28531.
b. deviation sensitivity
28532.
c. transconductance curve
28533.
d. phase deviation
28534.
29. When the modulating frequency is doubled, the modulation index is halved,
and the modulating voltage remains constant. The modulation system is
28535.
a. amplitude modulation
28536.
b. phase modulation
28537.
c. frequency modulation
28538.
d. any of the above
28539.
30. In PM, carrier frequency deviation is not proportional to:
28540.
a. modulating signal amplitude
28541.
b. carrier amplitude and frequency
28542.
c. modulating signal frequency
28543.
d. modulator phase shift
28544.
31. To compensate for increases in carrier frequency deviation with an increase in
modulating signal frequency, what circuit is used between the modulating signal and
phase modulator?
28545.
a. low-pass filter
28546.
b. high-pass filter
28547.
c. phase shifter
28548.
d. bandpass filter
28549.
32. Indicate which one of the following is not an advantage of PM over AM:
28550. a. better noise immunity is provided
28551.
b. lower bandwidth is required
28552.
c. the transmitted power is more useful
28553.
d. less modulating power is required
28554.
33. With phase modulation, the maximum frequency deviation occurs during what
value of the modulating signal?
28555.
a. positve peak value

28556.
b. rms value
28557.
c. negative peak value
28558.
d. zero crossings
28559.
34. With frequency modulation, maximum frequency deviation occurs _____ of
the modulation signal.
28560.
a. positive peak value
28561.
b. both positive and negative peak value
28562.
c. negative peak value
28563.
d. zero crossings
28564.
36. With phase modulation, peak phase deviation is called _________.
28565.
a. modulation index
28566.
b. frequency deviation
28567.
c. phase deviation
28568.
d. instantaneous phase
28569.
37. The FM produced by PM is called
28570.
a. FM
28571.
b. PM
28572.
c. indirect FM
28573.
d. indirect PM
28574.
38. In a broadcast superheterodyne receiver, the
28575.
a. local oscillator operates below the signal frequency
28576.
b. mixer input must be tuned to the signal frequency
28577.
c. local oscillator frequency is normally double the OF
28578.
d. RF amplifier normally works at 455kHz above the carrier frequency
28579.
39. If the amplitude of the modulating signal applied to a phase modulator is
constant, the output signal will be
28580.
a. zero
28581.
b. the carrier frequency
28582.
c. above the carrier frequency
28583.
d. below the carrier frequency
28584.
40. To prevent overloading of the last IF amplifier in the receiver, one should use
the
28585.
a. squelch
28586.
b. variable sensitiivity
28587.
c. variable selectivity
28588.
d. double conversion
28589.
41. The peak-to-peak frequency deviation is sometimes called __________.
28590.
a. phase deviation
28591.
b. peak phase deviation
28592.
c. carrier swing
28593.
d. instantaneous frequency
28594.
42. A 100MHz carrier is deviated 50 kHz by 4kHz signal. The modulation index
is
28595.
a. 5
28596.
b. 8
28597.
c. 12.5

28598.
d. 20
28599.
43. With angle modulation, it is defined as the ratio of the frequency deviation
actually produced to the maximum frequency deviation allowed by law stated in percent
form.
28600.
a. modulation index
28601.
b. percent modulation
28602.
c. frequency deviation
28603.
d. phase deviation
28604.
44. In a broadcast FM system, the input S/N = 4. Calculate the worst case S/N at
the output if the receiver's internal noise effect is negligible.
28605.
a. 19.8:1
28606.
b. 21.6:1
28607.
c. 23:1
28608.
d. 15:1
28609.
45. It is a circuit in which the carrier is varied in such a way that its instantaneous
phase is proportional to the modulating signal.
28610.
a. frequency modulators
28611.
b. amplitude modulators
28612.
c. phase modulators
28613.
d. mixers
28614.
46. In a ratio detector
28615.
a. the linearity is worse than in a phase discriminator
28616.
b. stabilization against signal strength variations is provided
28617.
c. the output is twice that obtainable from the similar phase discriminator
28618.
d. the circuit is the same as in a discriminator, except that the diodes are
reversed
28619.
47. The maximum deviation of an FM carrier is 2kHz by a maximum modulating
signal of 400Hz. The deviation ratio is
28620.
a. 0.2
28621.
b. 5
28622.
c. 8
28623.
d. 40
28624.
48. The unmodulated carrier is a single-frequency sinusoid commonly called
_________.
28625.
a. unrest frequency
28626.
b. rest frequency
28627.
c. frequency-modulated frequency
28628.
d. carrier frequency
28629.
49. It is a circuit in which the carrier is varied in such a way that its instantaneous
phase is proportional to the integral of the modulating signal
28630.
a. phase modulator
28631.
b. phase deviator
28632.
c. amplitude deviator
28633.
d. frequency modulator
28634.
50. The typical squelch circuit
28635.
a. cuts off an audio amplifier when the carrier is absent

28636.
b. eliminates the RF interference when the signal is weak
28637.
c. cuts off an IF amplifier when the AGC is maximum
28638.
d. cuts off an IF amplifier when the AGC is minimum
28639.
51. Frequency modulators are also known as _________.
28640.
a. phase deviators
28641.
b. frequency deviators
28642.
c. phase modulators
28643.
d. amplitude deviators
28644.
52. A 70 kHz carrier has a frequency deviation of 4 kHz with a 1000Hz signal.
What is the bandwidth of the FM signal?
28645.
a. 4kHz
28646.
b. 7kHz
28647.
c. 10 kHz
28648.
d. 28 kHz
28649.
53. The controlled oscillator synthesizer is sometimes preferred to the direct one
because
28650.
a. it is simpler piece of equipment
28651.
b. its frequency stability is better
28652.
c. it does not require crystal oscillators
28653.
d. it is relatively free of spurious frequencies
28654.
54. A system with a differentiator followed by an FM modulator is called
28655.
a. PM modulator
28656.
b. FM modulator
28657.
c. PM demodulator
28658.
d. FM demodulator
28659.
55. The image frequency of a superheterodyne receiver
28660.
a. is created within the receiver itself
28661.
b. is due to insufficient adjacent channel rejection
28662.
c. is not rejected by the IF tuned circuits
28663.
d. is independent of the frequency to which the receiver is tuned
28664.
56. A system with FM demodulator followed by an integrator
28665.
a. PM modulator
28666.
b. PM demodulator
28667.
c. FM modulator
28668.
d. FM demodulator
28669.
57. A system with an integrator followed by a PM modulator
28670.
a. PM modulator
28671.
b. FM modulator
28672.
c. PM demodulator
28673.
d. FM demodulator
28674.
58. An FM transmitter has a maximum deviation of 12kHz and a maximum
modulating frequency of 12 kHz. The bandwidth by Carson's rule is
28675.
a. 24kHz
28676.
b. 33.6kHz
28677.
c. 38.8kHz
28678.
d. 48kHz

28679.
59. A system with PM demodulator followed by a differentiator
28680.
a. PM modulator
28681.
b. FM modulator
28682.
c. PM demodulator
28683.
d. FM demodulator
28684.
60. A receiver has poor IF selectivity. It will therefore also have poor
28685.
a. blocking
28686.
b. double-spotting
28687.
c. diversity reception
28688.
d. sensitivity
28689.
61. Three point tracking is achieved with
28690.
a. variable selectivity
28691.
b. the padder capacitor
28692.
c. double spotting
28693.
d. double conversion
28694.
62. He mathematically proved that for a given modulating signal frequency a
frequency-modulated wave cannot be accommodated in a narrower bandwidth than an
amplitude modulated wave.
28695.
a. R.C. Alpine
28696.
b. E.H. Armstrong
28697.
c. J.R. Carson
28698.
d. J.J. Thomson
28699.
63. The maximum allowed deviation of the FM sound signal in TV is 25 kHz. If
the actual deviation is 18kHz, the percent modulation is
28700.
a. 43 percent
28701.
b. 72 percent
28702.
c. 96 percent
28703.
d. 139 percent
28704.
64. The local oscillator of a broadcast receiver is tuned to a frequency higher than
the incoming frequency
28705.
a. to help the image frequency rejection
28706.
b. to permit easier tracking
28707.
c. because otherwise an intermediate frequency could not be produced
28708.
d. to allow adequate frequency coverage without switching
28709.
65. Which of the following is not a major benefit of FM over AM?
28710.
a. greater efficiency
28711.
b. noise immunity
28712.
c. capture effect
28713.
d. lower complexity and cost
28714.
66. Low-index FM systems are also known as __________.
28715.
a. wideband FM
28716.
b. narrowband FM
28717.
c. commercial FM
28718.
d. medium FM
28719.
67. For high-index signal, a method of determining the bandwidth is called
________ approach

28720.
a. quasi-stationary
28721.
b. quasi-movement
28722.
c. quasi-deviation
28723.
d. any of these
28724.
68. When a receiver has a good blocking performance, this means that
28725.
a. it does not suffer from double-spotting
28726.
b. its image frequency rejection is poor
28727.
c. it is unaffected by AGC derived from a nearby transmission
28728.
d. its detector suffers from burnout
28729.
69. He established a general rule to estimate the bandwidth for all anglemodulated system regardless of the modulation index.
28730.
a. R.C. Alpine
28731.
b. E.H. Armstrong
28732.
c. J.R. Carson
28733.
d. J.J. Thomson
28734.
70. An AM receiver uses a diode detector for demodulation. This enables it
satisfactority to receive
28735.
a. single-sideband, suppressed carrier
28736.
b. single-sideband, reduced carrier
28737.
c. independent sideband
28738.
d. single-sideband, full carrier
28739.
71. The primary disadvantage of FM is its
28740.
a. higher cost and complexity
28741.
b. excessive use of spectrum space
28742.
c. noise susceptibility
28743.
d. lower efficiency
28744.
72. A rule that approximates the bandwidth necessary to transmit an anglemodulated wave as twice the sum of the peak frequency deviation and the highest
modulating frequency.
28745.
a. Carson's rule
28746.
b. Shannon's rule
28747.
c. Hartley's law
28748.
d. Hartley-Shannon law
28749.
73. It is the worst case modulation index and is equal to the maximum peak
frequency deviation divided by the maximum modulating signal frequency
28750.
a. peak phase deviation
28751.
b. frequency deviation
28752.
c. deviation ratio
28753.
d. signal to noise ratio
28754.
74. The receiver circuit that rids FM noise is the
28755.
a. modulator
28756.
b. demodulator
28757.
c. limiter
28758.
d. low-pass filter
28759.
75. The phenomenon of a strong FM signal dominating a weaker signal on a
common frequency is referred to as the

28760.
a. capture effect
28761.
b. blot out
28762.
c. quieting factor
28763.
d. domination syndrome
28764.
76. The highest side frequencies form one channel are allowed to spill over into
adjacent channels producing an interference known as _________.
28765.
a. co-channel interference
28766.
b. adjacent channel interference
28767.
c. splatter
28768.
d. overmodulation
28769.
77. A pre-emphasis is usually a ________.
28770.
a. high-pass filter
28771.
b. band-stop filter
28772.
c. low-pass filter
28773.
d. bandpass filter
28774.
78. Frequency modulation transmitters are more efficient because their power is
increased by what type of amplifier?
28775.
a. class A
28776.
b. class B
28777.
c. class C
28778.
d. all of the above
28779.
79. Noise interferes mainly with modulating signals that are
28780.
a. sinusoidal
28781.
b. non-sinusoidal
28782.
c. low frequencies
28783.
d. high frequencies
28784.
80. A de-emphasis is usually a _________.
28785.
a. high pass filter
28786.
b. band-stop filter
28787.
c. low-pass filter
28788.
d. bandpass filter
28789.
81. A pre-emphasis is a __________.
28790.
a. integrator
28791.
b. differentiator
28792.
c. either integrator or differentiator
28793.
d. neither integrator or differentiator
28794.
82. A de-emphasis is a _____________.
28795.
a. integrator
28796.
b. differentiator
28797.
c. either integrator or differentiator
28798.
d. neither integrator or differentiator
28799.
83. Pre-emphasis circuit boost what modulating frequencies before modulation?
28800.
a. high frequencies
28801.
b. mid-range frequencies
28802.
c. low frequencies
28803.
d. all of the above

28804.
84. The primary disadvantage of direct PM
28805.
a. relatively unstable LC oscillators must be used to produce carrier
frequency which prohibits using crystal oscillators
28806.
b. relatively high frequency deviations and modulation indices are easily
obtained due to the fact that the oscillators are inherently unstable.
28807.
c. crystal oscillators are inhrently stable and therefore more difficult
for them to achieve high phase deviations and modulation indices
28808.
d. carrier oscillator is isolated form the actual modulator circuit and
therefore can be stable source.
28809.
85. It is an angle modulation in which the frequency of the carrier is deviated by
the modulating signal
28810.
a. direct PM
28811.
b. PM
28812.
c. indirect FM
28813.
d. any of these
28814.
86. One of the following is a method of performing frequency up conversion
28815.
a. heterodyning
28816.
b. amplification
28817.
c. modulation
28818.
d. none of these
28819.
87. A pre-emphasis circuit is a
28820.
a. low-pass filter
28821.
b. high-pass filter
28822.
c. phase shifter
28823.
d. bandpass filter
28824.
88. Pre emphasis is compensated for the receiver by a
28825.
a. phase inverter
28826.
b. bandpass filter
28827.
c. high-pass filter
28828.
d. low-pass filter
28829.
89. A circuit that compares the frequency of the noncrystal carrier oscillator to a
crystal reference oscillator and then produces a correction voltage proportional to the
difference between the two frequencies
28830.
a. AFC
28831.
b. squelch circuit
28832.
c. AGC
28833.
d. heterodyning circuit
28834.
90. A frequency selective device whose output voltage is proportional to the
difference between the input frequency and its resonant frequency
28835.
a. modulator
28836.
b. squelch circuit
28837.
c. frequency discriminator
28838.
d. FM transmitters
28839.
91. Allows FM receiver to differentiate between two signals received with the
same frequency but different amplitudes
28840.
a. flywheel effect

28841.
b. amplitude limiting
28842.
c. noise immunity
28843.
d. capture effect
28844.
92. If an FM transmitter employs one doubler, one tripler, and one quadrupler,
what is the carrier frequency swing when the oscillator frequency swing is 2kHz?
28845.
a. 24 kHz
28846.
b. 48 kHz
28847.
c. 14 kHz
28848.
d. 12 kHz
28849.
93. The cut-off frequency of pre-emphasis and de-emphasis circuits is
28850.
a. 1 kHz
28851.
b. 2.122 kHz
28852.
c. 5 kHz
28853.
d. 75 kHz
28854.
94. Which of the following is not a disadvantage of angle modulation?
28855.
a. wide bandwidth
28856.
b. complex
28857.
c. high cost
28858.
d. less noise
28859.
95. In FM receivers, which of the following rejects the image frequency?
28860.
a. preselector
28861.
b. detector
28862.
c. IF amplifier
28863.
d. mixer
28864.
96. In FM receivers, which of the following provides most gain and selectivity of
the receiver?
28865.
a. detector
28866.
b. RF amplifier
28867.
c. local oscillator
28868.
d. IF amplifier
28869.
97. Another name for Voltage Variable Capacitor is
28870.
a. PIN diode
28871.
b. varactor diode
28872.
c. snap diode
28873.
d. hot carrier diode
28874.
98. The depletion region in a junction diode forms what part of a capacitor?
28875.
a. plates
28876.
b. leads
28877.
c. package
28878.
d. dielectric
28879.
99. Which of the following removes the information from the modulated wave in
FM receivers?
28880.
a. amplifiers
28881.
b. mixer
28882.
c. speakers
28883.
d. discriminator

28884.
100. The final IF amplifier in FM receivers is sometimes called ___________.
28885.
a. tuned amplifier
28886.
b. limiter
28887.
c. passband filter
28888.
d. any of these
28889.
101. _________ are frequency-dependent circuits designed to produce an output
voltage that is proportional to the instantaneous frequency at its output
28890.
a. PM receivers
28891.
b. PM demodulators
28892.
c. FM demodulators
28893.
d. FM receivers
28894.
102. Increasing the reverse bias on a varactor diode will it cause its capacitance to
28895.
a. decrease
28896.
b. increase
28897.
c. remains the same
28898.
d. drop to zero
28899.
103. The capacitance of a varactor diode is in what general range?
28900.
a. pF
28901.
b. nF
28902.
c. uF
28903.
d. F
28904.
104. Which of the following is the simplest form of tuned-circuit frequency
discriminator?
28905.
a. Foster-Seeley discriminator
28906.
b. Ratio detector
28907.
c. slope detector
28908.
d. PLL detector
28909.
105. It is simply two single-ended slope detectors connected in parallel and fed
180 degrees out phase.
28910.
a. Foster-Seeley discriminator
28911.
b. quadrature detector
28912.
c. balanced slope generator
28913.
d. PLL detector
28914.
106. The frequency change in crystal oscillator produced by a varactor diode is
28915.
a. zero
28916.
b. small
28917.
c. medium
28918.
d. large
28919.
107. A phase modulator varies the phase shift of the
28920.
a. carrier
28921.
b. modulating signal
28922.
c. modulating voltage
28923.
d. sideband frequency
28924.
108. Which of the following tuned-circuit frequency discriminator is relatively
immune to amplitude variations in its input signal?
28925.
a. ratio detector

28926.
b. slope detector
28927.
c. balanced slope detector
28928.
d. quadrature detector
28929.
109. In FM demodulators, it is also called coincidence detector
28930.
a. quadrature demodulator
28931.
b. PLL demodulator
28932.
c. Foster-Seely discriminator
28933.
d. ratio detector
28934.
110. The widest phase variation is obtained with ________.
28935.
a. RC low-pass filter
28936.
b. RC high-pass filter
28937.
c. LR low-pass filter
28938.
d. LC resonant circuit
28939.
111. An FM receiver provides 100dB of voltage gain prior to the limiter. Calculate
the receiver's sensitivity if the limiter's quieting for an FM receiver is 300mV?
28940.
a. 4.5 uV
28941.
b. 3.0 uV
28942.
c. 2.1 uV
28943.
d. 1.3 uV
28944.
112. The small frequency change produced by a phase modulator can be increased
by using ___________.
28945.
a. amplifier
28946.
b. mixer
28947.
c. frequency multiplier
28948.
d. frequency divider
28949.
113. In FM receiver, limiters produce a constant-amplitude output of all signals
above a prescribed minimum input level called _________.
28950.
a. threshold voltage
28951.
b. capture level
28952.
c. quieting level
28953.
d. any of these
28954.
114. The inherent ability of FM to diminish the effects of interfering signals is
called _______.
28955.
a. capture effect
28956.
b. noise suppression
28957.
c. adjacent channel rejection
28958.
115. A crystal oscillator whose frequency can be changed by an input voltage is
called _______.
28959.
a. VCO
28960.
b. VXO
28961.
c. VFO
28962.
d. VHF
28963.
116. Which oscillators are preferred for carrier generators because of their good
frequency stability?
28964.
a. LC
28965.
b. RC

28966.
c. LR
28967.
d. crystal
28968.
117. Which of the following frequency demodulators requires an input limiter?
28969.
a. Foster-Seely discriminator
28970.
b. Pulse-averaging discriminator
28971.
c. quadrature detector
28972.
d. PLL
28973.
118. Provides a slight automatic control over the local oscillator circuit and
compensates for its drift that would otherwise cause a station to become detuned.
28974.
a. AGC
28975.
b. AFC
28976.
c. VVC
28977.
d. VCO
28978.
119. ________ of an FM receiver is the maximum dB difference signal strength
between two received signals necessary for the capture effect to suppress the weaker
signal.
28979.
a. capture effect
28980.
b. capture gain
28981.
c. capture ratio
28982.
d. capture loss
28983.
120. When two limiter stages are used, there is called ___________.
28984.
a. double limiting
28985.
b. two-time limiting
28986.
c. reserve limiting
28987.
d. ratio limiting
28988.
121. Which discriminator averages pulses in a low-pass filter?
28989.
a. ratio detector
28990.
b. PLL
28991.
c. quadrature detector
28992.
d. pulse-averaging discriminator
28993.
122. Which of the frequency demodulator is considered the best overall?
28994.
a. ratio detector
28995.
b. PLL
28996.
c. quadrature
28997.
d. pulse-averaging discriminator
28998.
123. One of the prominent advantage of FM over PM is
28999.
a. FM requires frequency multipliers to increase the modulation index and
frequency deviation to useful levels
29000.
b. the voltage controlled oscillators of FM can be directly modulated
and produce outputs with high frequency deviations and high modulation
29001.
c. the modulation index of FM is independent of the modulating signal
frequency
29002.
d. FM offers better signal-to-noise performance than PM
29003.
124. What special speaker is used for low frequency?
29004.
a. baffle
29005.
b. base

29006.
c. tweeter
29007.
d. woofer
29008.
125. Each speaker assembly at the receiver reproduces exactly the same
information
29009.
a. monophonic
29010.
b. multiphonic
29011.
c. stereophonic
29012.
d. any of these
29013.
126. In a pulse averaging discriminator, the pulse are produced by a(n)
29014.
a. astable multivibrator
29015.
b. zero-crossing detector
29016.
c. one-shot
29017.
d. low-pass filter
29018.
127. A reactance modulator looks like a capacitance of 35pF in parallel with the
oscillator-tuned circuit whose inductance is 50 uH and capacitance is 40 pF. What is the
center frequency of the oscillator prior to FM?
29019.
a. 1.43 MHz
29020.
b. 2.6 MHz
29021.
c. 3.56 MHz
29022.
d. 3.8 MHz
29023.
128. The frequency of an SCA channel subcarrier is _______.
29024.
a. 38 kHz
29025.
b. 15 kHz
29026.
c. 67 kHz
29027.
d. 53 kHz
29028.
129. The L-R stereo channel in FM broadcasting is between
29029.
a. 50 Hz to 15 kHz
29030.
b. 60 kHz to 74 kHz
29031.
c. 23 kHz to 53 kHz
29032.
d. 20 Hz to 20 kHz
29033.
130. An FM demodulator that uses a differential amplifier and tuned circuits to
convert frequency variations into voltage variations is the
29034.
a. quadrature detector
29035.
b. Foster-Seeley discriminator
29036.
c. differential peak detector
29037.
d. phase-locked loop
29038.
131. The output amplitude of the phase detector in a quadrature detector is
proportional to
29039.
a. pulse width
29040.
b. pulse frequency
29041.
c. input amplitude
29042.
d. the phase shift value at center
29043.
132. The output to a PLL is 2MHz. In order for the PLL to be locked. The VCO
output must be
29044.
a. 0 MHz
29045.
b. 1 MHz

29046.
c. 2 MHz
29047.
d. 4 MHz
29048.
133. With stereo transmission, the maximum frequency deviation is
29049.
a. 75 kHz
29050.
b. 15 kHz
29051.
c. 25 kHz
29052.
d. 3 kHz
29053.
134. The L + R stereo channel occupies _________.
29054.
a. 50 Hz to 15 kHz
29055.
b. 60 kHz to 74 kHz
29056.
c. 23 kHz to 53 kHz
29057.
d. 20 Hz to 20 kHz
29058.
135. The band of frequencies over which a PLL will acquire or recognize an input
signal is called the
29059.
a. circuit bandwidth
29060.
b. capture range
29061.
c. band of acceptance
29062.
d. lock range
29063.
136. The three primary frequency bands are allocated by FCC for two-way FM
radio communications except:
29064.
a. 132 MHz to 174 MHz
29065.
b. 450 MHz to 470 MHz
29066.
c. 806 MHz to 947 MHz
29067.
d. 1026 MHz to 1035 MHz
29068.
137. The maximum frequency deviation for two-way transmitters is typically
29069.
a. 25 kHz
29070.
b. 5 kHz
29071.
c. 75 kHz
29072.
d. 3 kHz
29073.
138. Decreasing the input frequency to be locked PLL will cause the VCO output
to
29074.
a. decrease
29075.
b. increase
29076.
c. remains constant
29077.
d. jump to the free-running frequency
29078.
139. The range of frequencies over which a PLL will track input signal variations
is known as the
29079.
a. circuit bandwidth
29080.
b. capture range
29081.
c. band of acceptance
29082.
d. lock range
29083.
140. The maximum modulating signal frequency for two-way transmitter is
typically
29084.
a. 3 kHz
29085.
b. 5 kHz
29086.
c. 15 kHz

29087.
d. 75 kHz
29088.
141. Over a narrow range of frequencies, the PLL acts like a
29089.
a. low-pass filter
29090.
b. bandpass filter
29091.
c. tunable oscillator
29092.
d. frequency modulator
29093.
142. The output of a PLL frequency demodulator is taken from the
29094.
a. low-pass filter
29095.
b. VCO
29096.
c. phase detector
29097.
d. none of these
29098.
143. The primary advantage of FM over AM
29099.
a. capture effect
29100.
b. noise immunity
29101.
c. FM can use class C amplifiers
29102.
d. FM is more efficient
29103.
144. The usual cutoff frequency of pre-emphasis and de-emphasis in broadcast
FM?
29104.
a. 50 Hz
29105.
b. 75 Hz
29106.
c. 2122 Hz
29107.
d. 3183 Hz
29108.
145. The maximum deviation for narrowband FM?
29109.
a. 2500
29110.
b. 5
29111.
c. 1.67
29112.
d. 75
29113.
146. Which of the following is best frequency demodulator in use?
29114.
a. Foster-Seeley discriminator
29115.
b. ratio detector
29116.
c. slope detector
29117.
d. PLL
29118.
147. The range of frequencies over which the PLL will capture an input signal is
known as ________.
29119.
a. lock range
29120.
b. capture range
29121.
c. bandwidth
29122.
d. sidebands
29123.
148. Type of FM demodulator that is widely used in TV audio demodulators
29124.
a. ratio detector
29125.
b. quadrature detector
29126.
c. PLL
29127.
d. pulse-averaging discriminator
29128.
149. A variation of Foster-Seeley discriminator widely used in oldr TV receiver
designs
29129.
a. ratio detector

29130.
b. PLL
29131.
c. quadrature detector
29132.
d. crosby modulator
29133.
150. The range of frequencies over which a PLL will track an input is called
29134.
a. lock range
29135.
b. capture range
29136.
c. track range
29137.
d. driving range
29138.
151. What is the maximum deviation for monoaural TV sound
29139.
a. 25 kHz
29140.
b. 75 kHz
29141.
c. 50 kHz
29142.
d. 125 kHz
29143.
152. What is the maximum deviation for stereo TV sound?
29144.
a. 25 kHz
29145.
b. 75 kHz
29146.
c. 50 kHz
29147.
d. 125 kHz
29148.
153. In FM stereo broadcasting, the L + R signal
29149.
a. double-sideband modulates a subcarrier
29150.
b. modulates the FM carrier
29151.
c. frequency modulates a subcarrier
29152.
d. is not transmitted
29153.
154. In FM stereo broadcasting, the L - R signal
29154.
a. double-sideband modulates a subcarrier
29155.
b. modulates the FM carrier
29156.
c. frequency modulates a subcarrier
29157.
155. The SCA signal if used in FM broadcasting is transmitted via
29158.
a. a 19 kHz subcarrier
29159.
b. a 38 kHz subcarrier
29160.
c. a 67 kHz subcarrier
29161.
d. the main FM carrier
29162.
156. Which of the following is considered as an indirect method of generating
FM?
29163.
a. reactance modulator
29164.
b. balanced modulator
29165.
c. varactor diode modulation
29166.
d. armstrong system
29167.
157. In an FM system, if the modulation index is doubled by halving the
modulating frequency, what will be the effect on the maximum deviation?
29168.
a. remains the same
29169.
b. doubles
29170.
c. decrease by 1/2
29171.
d. increase by 1/4
29172.
158. Determine from the following the common use of DSB in broadcast and
telecommunication.

29173.
a. satellite communications
29174.
b. FM/TV stereo
29175.
c. two-way communications
29176.
d. telephone systems
29177.
159. Phase modulation emission type
29178.
a. F3F
29179.
b. G3E
29180.
c. F3E
29181.
d. F3C
29182.
160. The range of frequencies over which a PLL will cause the input of the VCO
signals to remain synchronized is known as the _________ range.
29183.
a. capture
29184.
b. lock
29185.
c. acquisition
29186.
d. any of these
29187.
161. If the PLL input is zero, the VCO will operate at its ____________
frequency.
29188.
a. free-running
29189.
b. natural
29190.
c. operating
29191.
d. any of these
29192.
162. Since a PLL will only respond to signals over a narrow frequency range, it
acts likes a ________.
29193.
a. low-pass filter
29194.
b. high-pass filter
29195.
c. bandpass filter
29196.
d. bandstop filter
29197.
163. In a PLL demodulating an FM signal, the VCO output is an exact
reproduction of the ___________.
29198.
a. modulating signal
29199.
b. carrier signal
29200.
c. carrier amplitude
29201.
d. VCO output
29202.
164. In a PLL demodulating an FM signal, the VCO output is an exact
reproduction of the ________.
29203.
a. FM input
29204.
b. VCO input
29205.
c. modulating signal
29206.
d. error signal
29207.
165. After the IF stages have been aligned, the next state to align in FM receiver is
29208.
a. local oscillator
29209.
b. limiter stage
29210.
c. RF amplifier
29211.
d. mixer stage
29212.
166. The modulation system used for telegraphy is
29213.
a. frequency-shift keying

29214.
b. two-tone modulation
29215.
c. purse-code modulation
29216.
d. single-tone modulation
29217.
167. What is emission F3F?
29218.
a. Facsimile
29219.
b. RTTY
29220.
c. modulated CW
29221.
d. television
29222.
168. What is a frequency discriminator?
29223.
a. a circuit for filtering two closely adjacent signals
29224.
b. a circuit for detecting FM signals
29225.
c. an FM generator
29226.
d. an automatic bandswitching circuit
29227.
169. Type of radio communication transmission utilizing frequency modulation
technique
29228.
a. television video
29229.
b. broadcasting in 535-1606 kHz
29230.
c. single sideband HF transmission
29231.
d. television audio
29232.
170. Why was FM first developed?
29233.
a. to compete with AM
29234.
b. to overcome noise
29235.
c. to increase listeners
29236.
d. to supplement AM
29237.
171. To what feature of the modulating tone is FM deviation proportional?
29238.
a. amplitude
29239.
b. frequency
29240.
c. phase
29241.
d. phase shift
29242.
172. Which of the following is not a basic filed of FM?
29243.
a. broadcast
29244.
b. TV video
29245.
c. mobile communications
29246.
d. amateur radio
29247.
173. Under what condition would a 1 kHz AF signal produce a single pair of FM
sidebands?
29248.
a. wideband
29249.
b. broadcast FM
29250.
c. TV audio FM
29251.
d. narrowband FM
29252.
174. What deviation is considered 100% for FM broadcast stations?
29253.
a. 75 kHz
29254.
b. 220 kHz
29255.
c. 270 kHz
29256.
d. 75 kHz or 220 kHz
29257.
175. In FM broadcasting, what is the highest required modulating frequency?

29258.
a. 75 kHz
29259.
b. 50 kHz
29260.
c. 25 kHz
29261.
d. 15 kHz
29262.
176. In FM broadcasting, what is the lowest required modulating frequency?
29263.
a. 50 Hz
29264.
b. 30 Hz
29265.
c. 10 Hz
29266.
d. 5 Hz
29267.
177. What is the disadvantage of slope detection of FM>
29268.
a. no discrimination against noise
29269.
b. less AF distortion
29270.
c. less AF out
29271.
d. no filtering of carrier
29272.
178. What is the unction of the dc that comes out of the dc amplifier in a PLLtype FM detector?
29273.
a. carrier signal
29274.
b. filter signal
29275.
c. error signal
29276.
d. phase signal
29277.
179. What is the function of the dc that comes out of the dc amplifier in a PLLtype FM detector?
29278.
a. oscillators
29279.
b. AF signal
29280.
c. RF signal
29281.
d. carrier signal
29282.
180. Why should discriminators be tuned for a straight characteristic S-curve?
29283.
a. less AF distortion
29284.
b. greater AF out
29285.
c. less RF out
29286.
d. less RF distortion
29287.
181. What band for high-Q coils be more desirable for stagger-tuned-type
discriminator transformer?
29288.
a. wide
29289.
b. intermediate
29290.
c. interfacing
29291.
d. narrow
29292.
182. In a Foster-Seeley circuit, the AF output voltage is ________.
29293.
a. varying DC
29294.
b. varying AC
29295.
c. steady DC
29296.
d. steady AC
183. In a stagger-tuned discriminator, the AF output voltage is _________.
29297.
a. varying DC
29298.
b. varying AC
29299.
c. steady DC

29300.
d. steady AC
29301.
184. In a ratio detector, the AF output voltage is
29302.
a. steady AC
29303.
b. varying AC
29304.
c. steady DC
29305.
d. varying DC
29306.
185. In a gated-beam detector, the AF output voltage is _________.
29307.
a. steady DC
29308.
b. varying AC
29309.
c. varying DC
29310.
d. steady AC
29311.
186. Which of the following discriminator circuits require limiters ahead of them?
29312.
a. quadrature detector
29313.
b. foster-seeley discriminator
29314.
c. slope detector
29315.
d. stagger-tuned
29316.
187. Which of the following discriminator circuits provide an automatic gain
control voltage?
29317.
a. ratio detector
29318.
b. balanced slope detector
29319.
c. quadrature detector
29320.
d. stagger-tuned detector
29321.
188. Which of the following discriminator circuits has its diodes in series?
29322.
a. ratio
29323.
b. quadrature detector
29324.
c. round-travis detector
29325.
d. slope detector
29326.
189. To what frequency must the gated-beam quadrature circuit be tuned in a TV
receiver?
29327.
a. 10.7 MHz
29328.
b. 455 kHz
29329.
c. 70 MHz
29330.
d. 4.5 MHz
29331.
190. To what frequency must the gated-beam quadrature circuit be tuned in an FM
broadcast receiver?
29332.
a. 4.3 MHz
29333.
b. 10.7 MHz
29334.
c. 11 MHz
29335.
d. 4.8 MHz
29336.
192. With what FM detectors would AGC be an advantage?
29337.
a. foster-seeley detector
29338.
b. ratio detector
29339.
c. quadrature detector
29340.
d. phase-locked loop
29341.
193. What is the reason for using pre-emphasis?
29342.
a. increase amplitude

29343.
b. reduce carrier shift
29344.
c. amplify RF signal
29345.
d. reduce noise reception
29346.
194. What are the two types of stages in an FM receiver that differ from those in
an AM receiver?
29347.
a. limiting IF and detectors
29348.
b. oscillators and IF amplifiers
29349.
c. mixers and RF amplifiers
29350.
d. local oscillators and mixers
29351.
195. What special circuits are used in a squelch system that can follow changing
noise levels?
29352.
a. noise amplifiers
29353.
b. rectifier
29354.
c. dc amplifier
29355.
d. any of these
29356.
196. Why might FM be better than AM for mobile ________.
29357.
a. better coverage
29358.
b. not affected by solar cycles
29359.
c. reduce flutter
29360.
d. not absorbed by ionosphere
29361.
197. What is the order of circuit alignment in an FM receiver?
29362.
a. discriminator, limiters, IF, mixer and RF
29363.
b. RF, limiters, IF, mixer and discriminator
29364.
c. limiters, mixer, RF, discriminator and IF
29365.
d. RF, mixer, RF, IF, limiters and discriminator
29366.
198. What is the another name for the reactance-tube modualtor?
29367.
a. Crosby
29368.
b. Foster-Seeley
29369.
c. Round Travis
29370.
d. Messier
29371.
199. What effect would be produced if a small inductance were used in plasce of
the 50 pF capacitance in the reactance-tube modulator?
29372.
a. the circuit becomes resistive
29373.
b. reactance modulator looks like an inductive circuit
29374.
c. reactance modulator looks like Xc
29375.
d. any of these
29376.
200. The following are significant circuits in the AFC system except:
29377.
a. crystal
29378.
b. mixer
29379.
c. IF
29380.
d. filter
29381.
201. Besides the reactance-tube modulator, what is another method of producing
direct FM?
29382.
a. armstrong modulator
29383.
b. voltage variable capacitor
29384.
c. impeadance modulator

29385.
29386.
29387.
29388.
29389.
29390.
29391.
29392.
29393.
29394.
29395.
29396.
29397.
29398.
29399.
29400.
29401.
29402.
29403.
29404.
29405.
29406.
29407.
29408.
29409.
29410.
29411.

d. slug indicator
202. What is the advantage of PM?
a. can use crystal oscillator
b. uses more multistage
c. less selective fading
d. simplicity
203. What was the first broadcast FM system called?
a. Arc transmitter
b. MOPA
c. Armstrong
d. crystal
204. Why are limtiers used in FM transmitters?
a. any of these
b. clip noise peaks
c. prevent overdrive of discriminators
d. prevent overdeviation
205. Why are limiters used in FM receivers?
a. provide better noise performance
b. clip noise peaks
c. prevent overdrive of discriminators
d. any of these
206. What signals might feed into an FM broadcast station audio control console?
a. microphones
b. turntables
c. remote lines
d. any of these
29412.

29413.
29414.
29415.
29416.
29417.
29418.

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