Adaptive Echo Cancellation Algorithm And Asic Implementation

Echo Canceller is function cell which cancells electrics echo or acoustics echo in communication systems . In systems such as MODEM, long distance telephone circuit , handfree telephone, telephone conference and so on echo cancellation theory has its important applications.This paper is to design a piece of integrated circuit?2 channel echo canceller.lt provides 32 independent and individually echo canceling to 32 channels, handling up to 64 ms of tail-end delay and 32 ms of additional programmable delay.The EC combines high performance,high flexibility,excellent maintenance capability, and low cost into a single package.On theory of echo cancel ing,this paper introduces a improved NLMS algorithm.Compared to IMS, it maintains complexity .improve speed convergence and induce error.According to EC's character of having good many operation, this paper put forword a high efficient hardware blue print.Operation of adaptive filter is handled by a specia module, all other operation by a custom-built DSP CORE. EC's micprocessor interface can provides much flexibility to user.The design follow advanced flow,use VerilogHDL and advanced EDA tool.According to ITU G.168, this EC get kinds of testing.All the testing achieve desire.