Patent ID: 8194852
Filing Date: 2012-06-05
Classification: H04M

Abstract:
1. A method for reducing echoes in an input signal containing an audio signal and an echo signal, the echo signal generated by a loudspeaker signal in a loudspeaker-room-microphone system, the method comprising: converting a portion of the input signal to microphone sub-band signals; down-sampling the microphone sub-band signals by a first down-sampling rate; converting the loudspeaker signal to echo sub-band signals; down-sampling the echo sub-band signals by a second down-sampling rate to generate down-sampled echo sub-band signals; folding the down-sampled echo sub-band signals with an estimated impulse response of the loudspeaker-room-microphone system to generate the folded down-sampled echo sub-band signals; down-sampling the folded down-sampled echo sub-band signals by a third down-sampling rate to generate estimated echo sub-band signals, where the first down-sampling rate is equal to the product of the second and third down-sampling rates subtracting for each sub-band, the estimated echo sub-band signal from the corresponding microphone sub-band signal to obtain error sub-band signals; and up-sampling and synthesizing the error sub-band signals to generate an echo compensated audio signal.