Voice call echo and background noise suppression method based on sliding mode variable structure control

Abstract

The invention discloses a voice call echo and background noise suppression method based on sliding mode variable structure control. The method comprises: S1, collecting original signals of echo and background noise in a call process by a near-end microphone, and establishes a sampling echo signal model; S2, setting an expected signal of the echo, establishing a sliding mode switching function foran error between an original signal of the echo and the expected signal, and discretizing the sliding mode switching function to obtain a discrete sliding mode function; S3, according to a sliding mode variable structure control algorithm, setting the sampling time, the sliding mode approaching speed and the high-frequency switching gain of the echo signal so as to determine a sliding mode band; S4, optimizing a sliding mode variable structure control algorithm by using a saturation function; S5, enabling the discrete sliding mode function to be equal to the sliding mode function of the optimized sliding mode variable structure control algorithm, and obtaining an expected signal expression of the echo in combination with the echo signal model; and S6, continuously predicting the echo signal of the next sampling point by using the expression, and subtracting the echo prediction signal of the same sampling point from the echo original signal to realize suppression of echo and call background noise.

Description

technical field [0001] The invention relates to the technical field of voice call signal processing of terminal equipment, in particular to a method for suppressing the echo generated by a mobile phone during a voice call and the floor noise of the call. Background technique [0002] Voice call echo, that is, when you make a call, what you say is transmitted back from the other party and heard by yourself. If the echo is large, it will seriously affect the communication of the caller. It is one of the important factors affecting the voice quality. Since the sound signal reaches the receiving device through different paths after being played by the playback device, the echo can be divided into line echo and acoustic echo at the receiving end. Line echo means that the sound signal played by the earpiece of the near-end mobile phone is directly received by the microphone of the mobile phone through various structural couplings and then transmitted back to the far end. Acoustic...

AI Technical Summary

Problems solved by technology

[0005] The main purpose of the present invention is to propose a voice call echo and floor noise suppression method based on sliding mode variable structure control, so as to solve the problem that the existing echo cancellation method has a high misjudgment rate and cannot accurately judge the change of the sounding state at the far and near ends. At the same time, the suppression of the background noise of the call is realized from the algorithm level

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