与VoIP声码器结合的回声消除器  

An Acoustic Echo Canceller Combined with VoIP

作　　者：吴雅婷[1] 胡海军[1] 张志军[1] 李挥[1] 

机构地区：[1]北京大学深圳研究生院信息学院,广东深圳510855

出　　处：《电声技术》2006年第5期68-71,共4页Audio Engineering

摘　　要：NLMS算法是回声消除器中最常用的算法之一,然而语音信号的强相关性使NLMS(归一化最小均方)算法的收敛速度变慢。鉴于VoIP(网络电话)常用的低速率声码器大多基于LP(线性预测)编码,给出了一种与声码器结合的回声消除器,通过利用从解码端获得的LP系数和激励信号,省去了对去相关滤波器系数的计算,并且不再需要专门的前置滤波器为远端信号去相关,同时又改善了回声消除器性能。仿真结果表现出更高的收敛速度和回声抵消量。NLMS（normalized least mean square）algorithm is widely used in echo canceller. However, due to high correlation of speech signals, the performance of echo canceller based on NLMS is depressed. An echo canceller integrated with vocoder in voice over IP system is presented. The new echo canceller using LP parameters and excitation signals recieved from decoder leaves out the calculation of decorrelation filter coefficients and the prewhitening of the received signal separately. Simulating results show a significant improvement of the performance.

关 键 词：回声消除 VoIP(网络电话) NLMS 线性预测 声码器 

分 类 号：TN912[电子电信—通信与信息系统]