Automatic gain control circuit and method for controlling gain adjustment speed in AGC system

Abstract

The invention discloses an automatic gain control circuit and a method for controlling gain adjustment speed in an AGC system. The automatic gain control circuit comprises a pre-stage operational amplifier, an operational amplifier output monitoring module, a forward and reverse counter, a decoder, an oscillator and a clock signal transmitter; the operational amplifier output monitoring module comprises a first comparator and a second comparator, and the clock signal transmitter is used for receiving clock signals output by the oscillator and outputting control signals to the forward and reverse counter according to output results of the first comparator and the second comparator; the forward and reverse counter is used for generating a gain amplitude adjusting signal according to the control signal and sending to the decoder; and the decoder controls the magnitude of the feedback resistance of the pre-stage operational amplifier according to the gain amplitude adjusting signal. According to the method, the gain adjusting speed in the AGC system is determined according to the time length that the output waveform of the operational amplifier exceeds the detection threshold value.

Description

technical field [0001] The invention relates to an automatic gain control circuit and a method for controlling gain and adjusting speed in an AGC system. Background technique [0002] At present, the automatic gain control function has been adopted by most audio power amplifiers. The AGC system (automatic gain control (AGC)) detects that the input signal exceeds the rated threshold voltage, and the AGC system actively reduces the gain of the op amp; when the input signal decreases and falls below the set release threshold, The AGC system actively restores the gain of the operational amplifier to ensure that the output signal power is maintained near the rated value. [0003] In the prior art, the method of detecting the peak output voltage of the op amp and then adjusting the feedback resistance of the op amp to reduce the gain has the defects that the gain adjustment method is too "hard", the adjustment speed is consistent, and not soft. In the field of audio applications...

AI Technical Summary

Problems solved by technology

[0004] The technical problem to be solved by the present invention is to provide an automatic gain control circuit and an automatic gain control circuit and an AGC system to overcome the defects of the prior art that the gain adjustment method is relatively single, the adjustment speed cannot be changed, and the effect on the audio equipment will affect the music listening effect. Gain adjustment speed method

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