Question

In a receiver, noise is usually developed at ________

(a) Audio stage

(b) Receiving antenna

(c) RF stage

(d) IF stage

I got this question in an interview.

This key question is from Receiver topic in section Elements of Communication System of Analog Communications

Answer 1

Correct option is (c) RF stage

For explanation I would say: Ability of receiver to selected only wanted signal, and reject other frequencies, out of the various incoming signals, helps the receiver to operate more efficiently. However, at times, the RF amplifier allows a frequency lying close to the desired frequency, to pass to the next stage. This other frequency is undesired and later on is responsible for production of image frequency. Thus, noise is usually developed at RF stage.