Automatic gain control system.

摘要

An automatic gain control system for controlling a gain of an A/D converter (2) automatically by controlling reference voltages of said A/D converter at the time of analog-to digital conversion of a signal which signal being clamped by a clamp circuit (1) to a clamp level which is set to a center level before entering said A/D converter, comprising a clamp level control circuit (3) for detecting the clamp level from an output of said A/D converter (2) to control the clamp level; a first D/A converter (4) for digital-to-analog converting an output of said clamp level control circuit (3); an automatic clamp level control system (5).