Filters
Content
Filters
Frequency selective device “Passband” “Stopband”
Four Main Filter Types: Low-pass High-pass Band-pass Notch (Band-stop)
Low-Pass Filter
Low-Pass Filter
Example
A simple RC circuit is to be used as LPF. It is desired that the O/P voltage be attenuated 3dB at 100 Hz. Calculate the required value of time constant T=RC. Solution20 log (Eo/Ei)= -3 Eo/Ei=0.707
Eo/Ei= 1/√(1+w²T²)=0.707 where w²=(2πf)²= [2π(100)]² T=1.59x10¯³ From T=RC C= 1µF ,R=1.59KΩ
High-Pass Filter
Frequency selective device “Passband” “Stopband”
Four Main Filter Types: Low-pass High-pass Band-pass Notch (Band-stop)
Low-Pass Filter
Low-Pass Filter
Example
A simple RC circuit is to be used as LPF. It is desired that the O/P voltage be attenuated 3dB at 100 Hz. Calculate the required value of time constant T=RC. Solution20 log (Eo/Ei)= -3 Eo/Ei=0.707
Eo/Ei= 1/√(1+w²T²)=0.707 where w²=(2πf)²= [2π(100)]² T=1.59x10¯³ From T=RC C= 1µF ,R=1.59KΩ
High-Pass Filter
