Patent ID: 7171003

Claim:
A cabin communication system for improving clarity of a voice spoken within an interior cabin having ambient noise, said cabin communication system comprising: an adaptive speech enhancement filter for receiving an audio signal that includes a first component indicative of the spoken voice, a second component indicative of a feedback echo of the spoken voice and a third component indicative of the ambient noise, said speech enhancement filter filtering the audio signal by removing the third component to provide a filtered audio signal, said speech enhancement filter adapting to the audio signal at a first adaptation rate; an adaptive acoustic echo cancellation system for receiving the filtered audio signal and removing the second component in the filtered audio signal to provide an echo-cancelled audio signal, said echo cancellation system adapting to the filtered audio signal at a second adaptation rate; and random noise adding means for adding random noise to the filtered audio signal, said echo cancellation system using the filtered audio signal with the random noise added thereto to identify the second component, wherein the random noise is a dither signal, and wherein the cabin is movable at a variable velocity and the dither signal is scaled to the velocity; wherein said first adaptation rate and said second adaptation rate are different from each other so that said speech enhancement filter does not adapt in response to operation of said echo-cancellation system and said echo-cancellation system does not adapt in response to operation of said speech enhancement filter.