ZHCSGM5A August 2017 – November 2017 TLV320AIC3109-Q1
PRODUCTION DATA.
If the input speech average value falls below the level determined by this threshold, the AGC considers the speech input to be silent and brings down the gain to 0 dB in steps of 0.5 dB every sample period and sets the noise threshold flag. The gain stays at 0 dB unless the input speech signal average rises above the noise threshold setting. This threshold ensures that noise is not gained up during times of silence. The noise threshold level in the AGC algorithm is programmable from –30 dB to –90 dB relative to full-scale. A disable noise gate feature is also available. This operation includes programmable debounce and hysteresis functionality to avoid the AGC gain from cycling between high gain and 0 dB when signals are near the noise threshold level. When the noise threshold flag is set, ignore the status of gain applied by the AGC and the saturation flag.