Patent ID: 6674865
Filing Date: 2004-01-06
Classification: H04M,H04R

Abstract:
An automatic gain control for a cabin communication system for improving clarity of a voice spoken within a movable interior cabin having ambient noise, said automatic gain control comprising:a microphone for receiving the spoken voice and the ambient noise and for converting the spoken voice and the ambient noise into a first audio signal having a first component corresponding to the spoken voice and a second component corresponding to the ambient noise; a filter for removing the second component from the first audio signal to provide a filtered audio signal; an acoustic echo canceller for receiving the filtered audio signal in accordance with a supplied dither signal and providing an echo-canceled audio signal; a control signal generating circuit for generating a first automatic gain control signal in response to a noise signal that corresponds to a current speed of the cabin, the first automatic gain control signal controlling a first gain of the dither signal supplied to said filter, said control signal generating circuit also for generating a second automatic gain control signal in response to the noise signal; and a loudspeaker for outputting a reproduced voice in response to the echo-canceled audio signal with a second gain controlled by the second automatic gain control signal.