Research On Echo Cancellation System Based On Microphone Array

Echo interference is common in speech communication system.The adaptive filtering technique of single microphone speech acquisition system can suppress echo to a certain extent.However,there are obvious drawbacks in signal processing in the field of sound field,for example,when echo interference is highly correlated with speech signal,the effect of echo suppression is not obvious.In view of the shortcomings mentioned above,this paper proposes an echo cancellation system based on microphone array.The coherent jamming zero filter is constructed by using sound source localization and beamforming technology.The speaker signal is filtered by the microphone array,and the signal to noise ratio of the speech signal is improved.The main work of this article is as follows:(1)the causes of echo generation are analyzed,and several commonly used echo cancellation methods are compared.The adaptive echo cancellation algorithm is emphatically analyzed.The results show that NLMS has small steady-state error,fast convergence speed and low algorithm complexity,and is very suitable for echo cancellation system with high real-time requirement.(2)the echo cancellation model of the master-slave filter is designed on the basis of the traditional dual end detection algorithm.In this model,the echo path estimation and echo cancellation division are carried out.In this model,the wideband speech signal is divided into multiple narrow band signals in the frequency domain,and the auxiliary filter is subband adaptive filtering.The system improves the efficiency and robustness of the system.(3)in order to solve the problem of coherent interference,the sound source localization and beamforming of uniform circular microphone array are explored,and the coherent interference null deepening algorithm based on enhanced principal singular vector modal analysis EPUMA is proposed.(4)the hardware test platform of echo cancellation system is built based on TMS320C6657 DSP,and the system is tested in the real meeting room.The internal system of 1.3s enters the stable working state.The test results show that the echo signal component of the echo cancellation system is distributed in-20~-18 dB after the echo cancellation,and the signal to noise ratio is improved by 6~7dB,which has met the practical performance.