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Vpp is Peak-to-Peak voltage, in other words, in AC voltage, the peak-to-peak vol tage is the potential difference between the lowest trough in the AC signal to t he highest. Assuming the reference to the voltage is zero, Vpp would be twice th e peak voltage (between zero and either the highest or lowest point in the AC wa veform). Vrms is the Root Mean Square voltage, think of it as sort of an average (it's no t quite that simple). For a sine wave, the RMS voltage can be calculated by y=a*sin(2ft) where f is the frequency of the signal, t is time, and a is the amplitude or pea k value.
Coherent Detection Coherent detection, also referred to as coherent demodulation, is a technique of phase locking to the carrier wave to improve detection. Knowledge of the carrie r phase improves demodulator performance. When an AM signal is received, the receiver must perform a converse process to g et the original signal ( Information Signal ) back . This process is known as detection or demodulation, the simplest process which i s used widely in AM radios is the Envelop Detector . Envelop Detector is an electronic circuit which is used to recover ( Demodulate ) the original signal in AM systems, its constructed from just one diode, one ca pacitor and one resistor .
Amplitude modulation - imposing a signal on the amplitude of a frequency - has t he effect of modifying the frequency a bit as well, and is much more susceptible to environmental noise such as lightning. Works well across much of the radio s pectrum. Frequency Modulation - imposing a signal by altering the frequency - it takes a very high frequency to modulate either audio or video signals - e.g. megahertz, so it eats up bandwidth. Phase modulation - by altering the phase with a desired signal - works when the bandwidth of the desired signal is very small - e.g. digital communications - bu t reflections of phase modulated signals can be easily corrupted. Radio frequenc y has a work to do in this field so an equipment is a must.
Coherent Detection Coherent detection, also referred to as coherent demodulation, is a technique of phase locking to the carrier wave to improve detection. Knowledge of the carrie r phase improves demodulator performance. When an AM signal is received, the receiver must perform a converse process to g et the original signal ( Information Signal ) back . This process is known as detection or demodulation, the simplest process which i s used widely in AM radios is the Envelop Detector . Envelop Detector is an electronic circuit which is used to recover ( Demodulate ) the original signal in AM systems, its constructed from just one diode, one ca pacitor and one resistor .
Amplitude modulation - imposing a signal on the amplitude of a frequency - has t he effect of modifying the frequency a bit as well, and is much more susceptible to environmental noise such as lightning. Works well across much of the radio s pectrum. Frequency Modulation - imposing a signal by altering the frequency - it takes a very high frequency to modulate either audio or video signals - e.g. megahertz, so it eats up bandwidth. Phase modulation - by altering the phase with a desired signal - works when the bandwidth of the desired signal is very small - e.g. digital communications - bu t reflections of phase modulated signals can be easily corrupted. Radio frequenc y has a work to do in this field so an equipment is a must.
