Communication Systems - Engineering

Q1:

A superheterodyne receiver is to operate in the frequency range 550 kHz - 1650 kHz, with the intermediate frequency of 450 kHz. Let denote the required capacitance ratio of the local oscillator and I denote the image frequency (in kHz) of the incoming signal. If the receiver is tuned to 700 kHz, then

A R = 4.41 J =1600

B R = 2.10 J =1150

C R = 3.0 J =1600

D R = 9.0 J =1150

ANS:A - R = 4.41 J =1600

Image frequency = 700 + 2 x 450 1600 kHz fmax = 1650 + 450 2100 kHz fmin = 550 kHz + 450 1000 kHz R = 4.41, I = 1600 kHz.