Patent ID: 9143862
Filing Date: 2015-09-22
Classification: H04M,H04R

Abstract:
1. A system for performing stereo audio echo cancellation (AEC), comprising: a stereo adaptive filter that receives a microphone signal and two channel speaker signals, where the two channel speaker signals have not yet had stereo AEC applied to them, the two channel speaker signals being received, respectively, from two separate speakers and where the stereo adaptive filter produces an echo removed microphone signal based on the microphone signal and the two channel speaker signals, where the stereo adaptive filter mitigates audio echo associated with the two channel speaker signals; a mono adaptive filter that receives the microphone signal and the two channel speaker signals and produces a second echo removed microphone signal based on a mixture of the two channel speaker signals, where the mono adaptive filter mitigates audio echo associated with the two channel speaker signals; a correlation detector that receives the two channel speaker signals and determines a level of correlation between the two channel speaker signals; an adaptive filter controller that selectively alters how the stereo adaptive filter adapts audio echo cancellation filtering based, at least in part, on the level of correlation between the two channel speaker signals, and that selectively alters how the mono adaptive filter adapts audio echo cancellation filtering based, at least in part, on the level of correlation between the two channel speaker signals, where the adaptive filter controller selectively adapts the rate at which the stereo adaptive filter adapts as a function of the level of correlation between the two channel speaker signals, and selectively adapts the rate at which the mono adaptive filter adapts as a function of the level of correlation between the two channel speaker signals; and a signal selector that inputs the echo removed microphone signal and determines a first value for an attribute of the echo removed microphone signal, inputs the second echo removed microphone signal and determines a second value for an attribute of the second echo removed microphone signal, and outputs the echo removed microphone signal or the second echo removed microphone signal based, at least in part, on a comparison of the first value and the second value, the first value being the power of the echo removed microphone signal, the second value being the power of the second echo removed microphone signal, and where the signal selector outputs the signal having the lower power.