description
AGC was i mplemented in first radiosfor the reason of fading propagation (defined as slow variations in the amplitude of the received signals) which required continuing adjustments inthe receiver’s gain in order to maintain a relative constant output signal. Such situation led tothe design of circuits, which primary ideal function wasto maintain a constant signal level at the output, regardless of the signal’s variations atthe input of the system. Now AGC circuits can be found in any device or system where wide amplitude variations inthe output signal could leadto a lost of information orto an unacceptable performance of the system.