Echo eliminating system for microphone echo

Abstract

Present invention discloses a microphone echo elimination system. It contains speech-sounds detection module, two ends simultaneousness sounding detection module, track filtering module, nonlinear processing module, and control module. Said invention can make adaptive filter reaching effectively eliminating echo target.

Description

technical field [0001] The invention relates to an echo cancellation system, in particular to a microphone echo cancellation system. Background technique [0002] The echo is caused by the acoustic loop between the speaker and the microphone. The sound signal from the far end is sent out through the speaker at the near end, collected by the microphone and transmitted back to the far end. At this time, the speaker at the far end can hear his own echo. Thereby seriously affecting the call quality. [0003] Since the acoustic loop from the loudspeaker to the microphone is unknown and time-varying, adaptive filtering is widely used in current echo cancellation schemes. figure 1 It is a schematic diagram of the circuit structure of an ordinary echo cancellation system, such as figure 1 As shown, the adaptive filter W(n) aims to minimize the residual echo e by adaptively adjusting the filter coefficients to track the speaker-to-microphone acoustic loop g(n), yielding a predicti...

AI Technical Summary

Problems solved by technology

[0004] However, in this echo cancellation scheme, some special situations cannot be effectively handled, such as: silence at both ends, talking at both ends at the same time, strong background noise, speaker and microphone, and signal nonlinear distortion caused by other factors, etc.

In some programs, modules such as VAD (Voice Activity Detection, voice detection), DTD (Double Talk Detection, simultaneous sound detection at both ends), NLP (Non-Linear Processor, nonlinear processing) are also used, but due to the lack of accurate control, so it is also difficult to achieve the expected conceived effect

For example: when using DTD based on correlation analysis, it is difficult to deal with the situation where there is a lot of background noise. An ideal compromise between effectively suppressing echo and maintaining near-end speech quality

[0005] Therefore, in the existing method for echo cancellation using adaptive filtering, there is a lack of accurate control of adaptive filtering, so in some occasions, for example: when both ends are silent, both ends are talking at the same time, strong background noise, etc., Adaptive filtering cannot work stably and efficiently, and even the coefficients diverge

As a result, the echo cannot be effectively eliminated, and even the noise is artificially introduced

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