用于语音处理的变步长LMS自适应增益控制新方案

针对语音通信系统中由于干扰、音频源不稳定等因素导致的接收端语音突变或响度不一致的问题，提出一种变步长最小均方误差自适应增益控制（VSSLMS-AGC，variable step size least mean square-adaptive gain control）新方案。该方案首先利用指数加权移动平均记录历史梯度信息，以此来调节最小均方误差算法的步长，使算法收敛速度更快，稳态误差更小；然后将变步长思想运用到自动增益控制中，确保能够自适应地调节语音增益值，使原先幅值不一的音频信号输出范围恒定且不失原有的特性，降低语音落差，改善听觉感受。 

New variable step size LMS adaptive gain control method for speech processing

Aiming at the problem of sudden changes or inconsistent loudness at the receiving end caused by factors such as interference and unstable audio sources in the voice communication system.A new VSSLMS-AGC (variable step size least mean square-adaptive gain control) method is proposed. First the method uses exponentially weighted moving average to record historical gradient information.This can adjust the step size of the least mean square algorithm, to make the algorithm converge faster and stabilize the error smaller.Then the variable step size idea is applied to automatic gain control,to ensure that the voice gain value can be adjusted adaptively.so that the output range of the original audio signal with different amplitudes is constant without losing the substantial characteristics,The method can reduce the sound drop and improve the auditory experience.