Patent ID: 7764783
Filing Date: 2010-07-27
Classification: H04M

Abstract:
1. An apparatus comprising: an analog-to-digital converter (ADC) operative to oversample an analog signal from a microphone and to provide a near-end signal having a wider bandwidth than bandwidth of a reference signal received via a communication channel; a subband filter operative to filter the near-end signal for a frequency band of interest and at least one other frequency band, to provide an in-band signal having spectral components in the frequency band of interest, and to provide an out-of-band signal having spectral components in the at least one other frequency band; an adaptive filter operative to receive the reference signal and the in-band signal, to derive an echo estimate signal with the reference signal, to cancel a portion of echo in the in-band signal with the echo estimate signal, and to provide an intermediate signal; and a double-talk detector operative to detect for double talk based on the out-of-band signal and the intermediate signal and to provide a control signal indicative of presence of double talk, and wherein the adaptive filter is updated based on the control signal, wherein the double-talk detector is operative to determine a power ratio based on the power of the out-of-band signal and the power of the intermediate signal and to detect for double talk based on the power ratio, and the double-talk detector is operative to determine the power ratio as: where P P k is a constant, and G(n) is the power ratio in time interval n.