The echo canceller is based on the MDF algorithm described in: J. S. Soo, K. K. Pang Multidelay block frequency adaptive filter, IEEE Trans. Acoust. Speech Signal Process., Vol. ASSP-38, No. 2, February 1990. We use the Alternatively Updated MDF (AUMDF) variant. Robustness to double-talk is achieved using a variable learning rate as described in: Valin, J.-M., On Adjusting the Learning Rate in Frequency Domain Echo Cancellation With Double-Talk. IEEE Transactions on Audio, Speech and Language Processing, Vol. 15, No. 3, pp. 1030-1034, 2007. http://people.xiph.org/~jm/papers/valin_taslp2006.pdf There is no explicit double-talk detection, but a continuous variation in the learning rate based on residual echo, double-talk and background noise. About the fixed-point version: All the signals are represented with 16-bit words. The filter weights are represented with 32-bit words, but only the top 16 bits are used in most cases. The lower 16 bits are completely unreliable (due to the fact that the update is done only on the top bits), but help in the adaptation -- probably by removing a "threshold effect" due to quantization (rounding going to zero) when the gradient is small. Another kludge that seems to work good: when performing the weight update, we only move half the way toward the "goal" this seems to reduce the effect of quantization noise in the update phase. This can be seen as applying a gradient descent on a "soft constraint" instead of having a hard constraint.

ti 基于 定点dsp的 lms 回声消除算法，很有用的

音频回声消除算法

这个算法是NLMS的,里面不仅有算法还有解释,而且这个回声消除不止是回声消除,还有其他模块,比如双向通话检测模块,高通滤波模块.源代码在最后一点,需要自己复制出来,这个代码我已经编译过了,能够运行,但是在我的ARM板子上跑起来很慢.

本文档将现在国内外流行的关于会啊生消除放卖弄的算法进行了一个横向和纵向的比较，非常实用，简明。是一份不可多得的好资料。

回声消除算法文档资料，包含测试文件，源程序和一些文档。