Automatic Gain control system

摘要

A digital automatic gain control system for maintaining a constant output level through attenuating or amplifying an input signal is disclosed. The system includes a gain control providing an output signal by amplifying or attenuating an input signal in a step mode in response to digital data of a data bus, a comparator deciding with a digital output whether or not said output signal is within a window reference voltage range, a stage preventing a malfunction due to noise by means of performing a counting operation upon receiving said digital output, a clock generating a clock pulse and dividing the frequency of the clock pulse, whereby there is provided a divided clock in case of performing an up counting operation and to the contrary there is provided the non-divided clock pulse in case of performing a down counting operation, and generating a reset clock delayed by a specified time interval from said clock, a latch adapted to receive and thereby latch an output of preventing stage malfunction, and reset clock and up/down counting and logic performing the up or down counting operation by receiving said clock and a latch signal.