Question

Superheterodyne principle provides selectivity at ________

(a) RF stage

(b) IF stage

(c) Demodulating Stage

(d) Audio Stage

The question was asked in exam.

I would like to ask this question from Receiver in portion Elements of Communication System of Analog Communications

Answer 1

Right choice is (b) IF stage

To explain: A superheterodyne receiver uses frequency mixing to convert the received high frequency signal to a fixed lower intermediate frequency (IF), which can be processed more conveniently than original received frequency. Thus, the principle of selectivity is applied at the IF stage as it consists of very efficient filters to only select a wanted signal and pass it to the Demodulating Stage.