auto-gain control的意思|示意

Auto-gain control (AGC) refers to a method of setting the signal level of an audio-processing device, such as an amplifier, equalizer, preamp, or sound compressor, automatically to a predetermined value. The signal level is usually in decibels, relative to some reference level.

The purpose of AGC is to prevent the signal level from rising too high or falling too low. In many cases, it can be used to optimize the signal-to-noise ratio (SNR) at the input of a system, so that the signal is amplified, but the noise is attenuated. AGC can also be used to make sure the signal level is consistent, regardless of changes in the signal level of the source material.

The basic principle behind AGC is to measure the incoming signal level, and then adjust the gain of the audio processing device to keep the signal level at the desired level. This is done by measuring the signal level with a detector, and then using a control circuit to adjust the gain of the device.

There are several different types of AGC. The most common type is a feedback type, in which the gain is adjusted in response to a feedback signal from the detector. Another type of AGC is an adaptive type, which uses a preset level as a reference. The gain is adjusted accordingly, without any feedback from the detector.

AGC can be used in a wide range of applications, such as digital audio processing, broadcasting, and recording. It is also used in many consumer electronics, such as television sets, video players, and CD players.

In summary, auto-gain control (AGC) is a method used to ensure that the signal level is kept at a predetermined level, so that the signal-to-noise ratio is optimized, and the signal level is consistent, regardless of changes in the signal level of the source material. It is used in many different applications, including digital audio processing, broadcasting, and recording.