What is Automatic Gain Control (AGC) and why is it important in receivers?

AGC automatically adjusts receiver gain to maintain constant output level despite varying input signal strength. Components include: signal level detector, reference comparator, and variable gain amplifier. AGC is important because: received signal can vary over 100dB range (near/far problem), prevents overload distortion with strong signals, maintains optimal SNR with weak signals, and keeps subsequent stages operating in linear range. AGC loop bandwidth trades off response speed versus noise immunity. Fast AGC handles rapid fading; slow AGC for stable channels.