Harmonic distortion residual echo suppression

A system for suppressing a portion of a microphone signal corresponding to a playback of the multiple channels of a speaker audio signal wherein each channel is played aloud via separate loudspeakers in a space having a microphone therein which picks-up said playback and generates a microphone signal, wherein a portion of the microphone signal that corresponds to each channel of the speaker audio signal playback comprises non-linear harmonic distortion caused by the speaker audio signals, said system comprising:

• a multi-channel acoustic echo canceller (AEC) module which suppresses a first part of the playback of the multiple channels of the speaker audio signal found in the microphone signal and which generates an AEC output signal;
• a first harmonic distortion residual echo suppression (HDRES) module which inputs the AEC output signal and a first one of the channels of the speaker audio signal, and suppresses at least a portion of a residual part of the speaker audio signal playback of the first input channel found in the microphone signal which was left unsuppressed by the AEC module, as well as at least a portion of the harmonic distortion exhibited in the AEC output signal caused by the first input channel of the speaker audio signal playback, to produce a first HDRES output signal;
• and
• one or more additional HDRES modules each of which inputs the signal output by the preceding HDRES module and an additional channel of the speaker signal not yet input by a HDRES module, and suppresses at least a portion of a residual part of the speaker audio signal playback of the additional input channel which was left unsuppressed by the AEC module and all preceding HDRES modules, as well as at least a portion of the harmonic distortion exhibited in the AEC output signal caused by the additional channel of the speaker audio signal playback which was left unsuppressed by the AEC module and all preceding HDRES modules, to produce an additional HDRES output signal, and wherein the last HDRES output signal output by the last HDRES module is designated as the final HDRES signal.

A system for suppressing a portion of a microphone signal corresponding to a playback of the right and left channels of a speaker stereo audio signal wherein each channel is played aloud via separate loudspeakers in a space having a microphone therein which picks-up said playback and generates the microphone signal, wherein a portion of the microphone signal that corresponds to each channel of the speaker audio signal playback comprises non-linear harmonic distortion caused by the playback, said system comprising:

• an stereo acoustic echo canceller (AEC) module which suppresses a first part of the playback of the left and right channels of the speaker signal found in the microphone signal and which generates an AEC output signal;
• a first harmonic distortion residual echo suppression (HDRES) module which inputs the AEC output signal and one of the (i) sum of the right and left channels of the speaker signal or (ii) the difference of the right and left channels of the speaker signal, and suppresses at least a portion of a residual part of the speaker signal playback of the input channel sum or difference found in the microphone signal which was left unsuppressed by the AEC module, as well as at least a portion of the harmonic distortion exhibited in the AEC output signal caused by the speaker audio signal playback channels, to produce a first HDRES output signal;
• and
• a second HDRES module which inputs the first HDRES output signal and either the sum or difference of the right and left channels of the speaker signal whichever was not input by the first HDRES module, and which suppresses at least a portion of a residual part of the speaker signal playback of the input channel sum or difference found in the microphone signal which was left unsuppressed by the AEC module and the first HDRES module, as well as at least a portion of the harmonic distortion exhibited in the AEC output signal caused by the speaker audio signal playback channels which was left unsuppressed by the AEC module and the first HDRES module, to produce a final HDRES output signal.