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Acoustic echo removing method

An acoustic echo cancellation and noise cancellation technology, applied in the field of acoustic echo cancellation in the echo cancellation technology, can solve the problems of intermittent echo or sound, slow convergence, easy divergence, etc., to reduce the divergence speed, improve the ability of echo cancellation, and solve the echo effect of the problem

Inactive Publication Date: 2007-05-02
SHANGHAI BEILING
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Problems solved by technology

The traditional least mean square converges slowly and is easy to diverge. It can only eliminate the remaining echo, so a nonlinear method has to be used to eliminate the remaining echo. Although this method is better than the gain adjustment method, it still has many shortcomings. Intermittent sound occurs

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Embodiment Construction

[0015] Referring to FIG. 2 , which is a schematic diagram of the acoustic echo cancellation method of the present invention.

[0016] The present invention is used for acoustic echo cancellation, and adopts unique adaptive step size nonlinear filtering technology, that is, adopts the standardized least mean square algorithm in adaptive step size sub-band, and adopts the beam forming nonlinear filtering technology to eliminate noise.

[0017] Assumptions: h(n) is the echo channel response, X(n) is the reference signal, C(n) is the adaptive filter coefficient, and E(n) is the signal at the receiver of the microphone.

[0018] E(n)=X(n)*h(n) (convolution)

[0019] E(n)=EL(n)(linear)+EN(n)(non-linear)

[0020] C(n+1)=C(n)+ΔC(n)

[0021] ΔC(n)=μX(n)e(n) / ‖x(n)‖ 2 (μ is the adaptive step size)

[0022] (n)=X(n)*C(n) (convolution)

[0023] e(n)=E(n)-(n)

[0024] In order to eliminate echoes, acoustic echo cancellation must have the function of dynamically learning the acoustic ...

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Abstract

This invention relates to a method for eliminating acoustic echo including the following steps: the minimum mean square algorithm of adaptive step wave band standardization, eliminating wave beams of noises to form non-linear filter to eliminate acoustic echoes. This invention applies an exclusive adaptive step non-linear filter technology to divide signals into multiple wave bands for process and alter steps adaptively according to the echo environment to eliminate echoes to increase convergence speed and reduce radiation speed to improve the ability for eliminating echo.

Description

technical field [0001] The present invention relates to an echo cancellation method, in particular to an acoustic echo cancellation method in the echo cancellation technology. Background technique [0002] Acoustic echo means that the sound played by the speaker is picked up by the microphone and sent back to the far end, which enables the far end talker to hear their own voice. Acoustic echo is divided into direct echo and indirect echo. Direct echo means that the sound played by the speaker enters the microphone directly without any reflection. This echo delay is the shortest, and it is related to the speech energy of the far-end speaker, the distance and angle between the speaker and the microphone, the playback volume of the speaker, and the pickup sensitivity of the microphone. Indirect echo refers to the set of echoes produced by the sound played by the loudspeaker after being reflected one or more times through different paths into the microphone. Because the chang...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04M9/08
Inventor 韩兴成叶波王祥莉
Owner SHANGHAI BEILING
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