Question

The disadvantage of preset equalizer is that

(a) It doesnot requires initial training pulse

(b) Time varying channel degrades the performance of the system

(c) All of the mentioned

(d) None of the mentioned

This question was posed to me in an interview for internship.

This key question is from Equalization and Non Coherent Detection in division Baseband Demodulation and Detection of Digital Communications

Answer 1

Right choice is (b) Time varying channel degrades the performance of the system

For explanation I would say: The disadvantage of preset equalization is that it requires an initial training period that must be invoked at the start of any new transmission. Also time varying channel can degrade system performance due to ISI, since the tap weights are fixed.