Communication Systems - Engineering

Q1:

Consider the following statements as regards communication receiver
  1. Variable sensitivity is used to eliminate selective fading
  2. A product demodulator can be used to receive Morse code
  3. The noise limiter cuts off receiver output during a noise pulse
  4. Double conversion is used to improve image rejection
Which of the above statements are correct?

A 1, 2, 3, 4

B 1, 2, 3

C 2, 3, 4

D 1, 3, 4

ANS:C - 2, 3, 4

Variable sensitivity is used to improve selectivity.