Voice codec automatic gain control

摘要

An Automatic Gain Control System for voice codecs used in a digital wireless handset or in any other environment where there is a large amount of background noise. The invention utilizes the processing power available in Digital Signal Processor 111 to adaptively adjust the gain of amplifier 202 and filter 205 in the transmit channel to eliminate audio distortion in a "loud talker" environment. The gain correction information is transmitted by the DSP 111 to the digital filter and PCM I/O block 204 in the 3 unused bits of the 16 bit PCM data word thus eliminating any additional connections.