US 4,379,272 A · AGC Circuit with level-compensating input

Abstract

An automatic gain control (AGC) circuit arrangement is disclosed as including an AGC loop responsive to an input signal and operative to maintain an output signal at a desired mean level represented by a reference signal applied in the loop and also subjected to amplitude modulation by an AF signal. The circuit arrangement includes modulators outside the loop for changing the level of the input signal by amounts corresponding respectively to changes in level represented by changes in the AF signal and by changes in the reference signal. Therefore, the level of the input signal as received by the AGC loop is at least approximately at the right value and its gain is held substantially constant even when the level of the required output signal for a given input signal changes. Therefore, variations of bandwidth resulting from gain variations are avoided.

Claims3

Dependent claims

In an electrical circuit arrangement for automatic gain control including an AGC loop responsive to an input signal and operative to maintain an output signal at a desired mean level represented by a reference signal applied in the loop,

level changing means outside the loop and connected to change the level of the input signal by an amount corresponding to changes in level represented by changes in the reference signal, so that the level of the input signal as received by the AGC loop is at least approximately at the right value.

Dependencies are inferred from the claim text.

AGC Circuit with level-compensating input

Life of this patent

AGC Circuit with level-compensating input

Life of this patent

Abstract

Claims3