Research And Implementation Of Acoustic Echo Cancellation Algorithm

With the rapid development of communication techniques, digital signal processing and VLSI techniques, people demand higher and higher speech quality in communication. So acoustic echo cancellation (AEC) technique has become a hotspot of competition in famous communicaton company all over the world.However, it is not always easy to implement acoustic equipments for communication system with satisfactory speech quality. The technology of echo cancellation has been a very active research field in recent years.This paper is focused on the AEC in communication system,e.g. tele-conference, video-conference.Acoustic echo cancellation is normally achieved by means of an acoustic echo canceller,which,in its simplest form,consists of an adaptive filter which mimics the transfer function of the echo path (or room acoustic ) to synthesize a replica of the echo,and then subtracts the estimation from the combined echo and near-end speech(or disturbance)signal to obtain the near-end signal alone. This paper is organized as follows:The background knowledge about echo canceller such as echo mechanism, basic principle of echo canceller and basic components of echo canceller is introduced in chapter 1In chapter 2 , many kinds of adaptive filter algorithms are dicussed,and their merit and demerit are analyzed .To solve the tradeoff between congverence and computational complexity, BEFAP is proposed in chapter 3,which is based on block-exact processing and affine projection algorithm.Chapter 4 offers hardware and software implementation of the acoustic echo canceller based on TMS320VC5409 DSP ,which can be applied to a terminal of the tele-conference or video-conference.Through simulation and test, Chapter 5 analyzes and evaluates the main performance of the proposed algorithm and gets the result as expected.