Receivers

Explanation of question 16

A transmitted signal being received by a receiver suddenly increases in strength. The automatic gain control (a.g.c.) of the receiver will

1. increase the background noise to maintain a constant signal-to-noise ratio
2. lower the amplification of the receiver
3. buffer the oscillator
4. slightly off-tune the receiver to reduce the signal strength

The answer is :- 2 The function of automatic gain control is to ensure the receiver output remains sensibly constant. The amplification in this particular case will be lowered, in order to maintain constant output level.