基于TMS320DM642实现的一种低复杂度回声抵消器

A Low Complexity Echo Canceller on TMS320DM642

以TMS320DM642定点DSP为平台,实现了一种低复杂度并适应双端会话情况的回声抵消器。在算法上,为提高双端会话的鲁棒性,采用了双回声路径模型(two echo path model,TEPM)作为基本框架;为降低计算的复杂度,采用了多延时分块频域自适应滤波器(multi-delay block frequency domain adaptive filter,MDF)估计回声路径的冲击响应。在实现上,针对DSP的并行执行能力和指令集的单指令多数据(SIMD)特性对主要运算进行了线性汇编级的优化。测试表明,这种回声抵消器可以在0.45%CPU占用率下处理128ms路径延时的组合声源信号(composite source signal,CSS)和实际声源信号的回声。

We developed a low complexity echo canceller suitable for double talk cases on DSP TMS320DM642. It uses the two echo path model （TEPM） as the basic structure to enhance robustness under double talk, and the multi-delay block frequency domain adaptive filter （MDF） as the echo path impulse response estimator to lower computational complexity. For implementation, the echo canceller takes the advantages of parallel processing power and single instruction multiple dala （SIMI）） capability of the DSP through linear assembly level optimization for main operations. It is shown that the echo canceller is able to process echoes with path delay up to 128 ms at 4.5% CPU load for composite source signals and real source signals.