Subband domain echo masking for improved duplexity of spectral domain echo suppressors

摘要

A method and system for improving a perceived duplexity of handsfree telephone applications is disclosed. An echo suppression circuit for a device comprising loudspeaker and microphone is described. A circuit attenuates a subband of a transmit signal, wherein the transmit signal is captured by the microphone and wherein the transmit signal comprises an echo of a far-end signal rendered by the loudspeaker and a near-end signal. The attenuation circuit further determines a subband far-end indicator of a voice activity in the far-end signal; determines a subband near-end indicator of a voice activity of the near-end signal; determines a subband masking weight; determines a subband attenuation for the transmit signal in the subband; and attenuates the subband of the transmit signal using the determined subband attenuation.

主权项

1. An echo suppression circuit for an electronic device comprising a loudspeaker and a microphone; wherein an attenuation circuit is configured to attenuate a subband of a transmit signal; wherein the transmit signal is captured by the microphone; wherein the transmit signal comprises an echo of a far-end signal rendered by the loudspeaker and a near-end signal;
wherein the attenuation circuit is configured to determine a subband far-end indicator of a voice activity in the far-end signal based on the far-end signal in the subband; determine a subband near-end indicator of a voice activity of the near-end signal based on the far-end signal and based on the transmit signal in the subband; determine a subband masking weight, based on the subband far-end indicator and based on the subband near-end indicator; wherein the subband masking weight is indicative of a masking of the echo of the far-end signal by the near-end signal in the subband; determine a subband echo path filter coefficient based on a correlation between the transmit signal and the far-end signal in the subband; wherein the estimate of the level of the echo of the far-end signal in the subband corresponds to a level of the far-end signal in the subband multiplied by the subband echo path filter coefficient; determine a subband attenuation for the transmit signal in the subband based on an estimate of a level of the echo of the far-end signal in the subband and based on the subband masking weight, by weighting the subband echo path filter coefficient with the subband masking weight; and attenuate the subband of the transmit signal by subtracting the level of the far-end signal in the subband multiplied by the subband attenuation from a level of the transmit signal in the subband.