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VAD (Voice Activity Detection) algorithm analyses voice activity to detect silence intervals.
During silence period VAD sends background noise information to CNG (Comfort Noise Generator) module that generates comfort noise.
VAD and CNG algorithms can be effectively used with vocoders and echo cancellers as well as with other applications where it is important to reduce the transmitted bit rate.
The CNG algorithm runs at the receive side the link.
When speech is not present, the CNG algorithm generates a noise signal at the level sent from the transmit side.
The AGC algorithm adjusts the voice power level to a user specified target within user specified time constant.
The AGC is integrated with the Voice Activity Detection algorithm to ensure that background noise or echo does not get amplified up to the specified target level.
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