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Proportional self-adaption telephone echo cancellation method based on decorrelation

An echo cancellation and proportional technology, which is applied in the telephone structure, two-way sound reinforcement telephone system, side tone cancellation circuit, etc., can solve the problems of slow convergence speed, achieve fast convergence speed, improve tracking ability, and good effect Effect

Inactive Publication Date: 2014-11-12
SOUTHWEST JIAOTONG UNIV
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Problems solved by technology

However, the algorithm still exhibits the defect of slow convergence when dealing with related signals (such as speech signals)

Method used

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  • Proportional self-adaption telephone echo cancellation method based on decorrelation
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  • Proportional self-adaption telephone echo cancellation method based on decorrelation

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Embodiment

[0044] A proportional adaptive telephone echo cancellation method based on decorrelation, its steps are as follows:

[0045] A. Remote signal filtering

[0046] A1. Sampling the remote signal from the far end to obtain the remote signal discrete value x(n), where n is the current moment, and the remote signal discrete value x(n) is the difference between the current moment n and the previous L-1 moment The value constitutes the adaptive filter input vector X(n) at the current moment, X(n)=[x(n), x(n-1), ..., x(n-L+1)] T , where L=512 is the number of filter taps, and T represents the transpose operation;

[0047] A2, pass the filter input vector X(n) through the adaptive filter to obtain the output value y(n), that is, the estimated value y(n) of the echo, y(n)=w T (n)X(n); Wherein, w(n) is the tap weight vector of current moment adaptive filter, w(n)=[w 0 (n),w 1 (n),...,w L-1 (n)] T , whose length is L and whose initial value is a zero vector;

[0048] B. Decorrelatio...

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Abstract

A proportional self-adaption telephone echo cancellation method based on decorrelation mainly includes the steps that (A) far-end signal filtering is carried out to obtain an output value y (n) of an adaptive filter; (B) a decorrelation operation of an input vector X (n) is conducted to obtain an innovation vector Z (n) of a tap weight vector w (n) of the adaptive filter, namely Z (n)= X (n) - a (n) X (n-1); (C) echo cancellation is carried out, wherein the output value y (n) of the adaptive filter is subtracted from a near-end signal d (n) with an echo picked up by a near-end microphone, then the near-end signal d (n) with the echo is sent back to a far-end, and a loopback signal d (n) is a useful signal e (n) of an identification cancellation echo obtained by subtracting d (n) from y (n), namely e (n)= d (n) - y (n); (D) the tap weight vector of the filter is updated; (E) the equation that n= n+1 is made, and the steps from A to D are repeated until a call is ended. The method has high identification capacity for sparse systems like telephone communication, and is high in convergence rate, low in steady state error and good in echo cancellation effect.

Description

technical field [0001] The invention belongs to the technical field of adaptive echo cancellation for telephone communication. Background technique [0002] With the development of communication technology, various new services emerge in an endless stream, but the voice service is still the most important communication method. Acoustic echo is the most important factor affecting voice call quality, so echo cancellation is one of the key technologies to improve call quality. During the communication process, the voice of the far-end speaker is played through the near-end speaker, and is received by the near-end microphone directly (without any reflection) or indirectly (after one or more reflections from the house or objects in the house), and transmitted back to the far-end speaker. end, so that the far-end talker hears his own voice, which is the acoustic echo. The sound propagation path from the speaker to the microphone, also known as the echo channel, is represented by...

Claims

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Application Information

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IPC IPC(8): H04M9/08H04M1/20H04M1/58
Inventor 赵海全董银霞
Owner SOUTHWEST JIAOTONG UNIV
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