Improved method of automatic gain control in a superheterodyne receiver of radio signals and circuits for the implementation of this method.

摘要

P The method relates to the use of an intermediate frequency in a circuit for receiving and demodulating microwave signals, prior to their amplification. According to the invention, a clever choice of intermediate frequency allows the easy realization of this circuit. The proposed solution is to choose an intermediate frequency for the reception circuit which corresponds to a frequency commonly used in televisions and video recorders. This advantageous choice of intermediate frequency allows the use of a very common and therefore inexpensive component, a video delay line, to allow an open loop to act on the gain of the amplifier before the application of the signal to his entry. A system according to the invention therefore contains a video delay line at the chosen intermediate frequency which delays the signal before the input of an amplifier whose gain is controlled by an open loop. Application in telecommunications, particularly in TDMA. /P