In order to cancel the reflecting echo of telephone speech interactive system

the telephone channel and line echo were studied.The channel impulse response is firstly estimated

and the convolution of channel impulse response and suggestive speech is calculated

which will be used to counteract the echo.The time delay between echo and primary signal is estimated and canceled using de-convolution or Cross-power Spectrum Phase method before the channel impulse response is estimated.This algorithm can get better echo canceling and primal speech fidelity than LMS adaptive filter.After Echo Cancellation

the speech recognition correction rate and accuracy rate are improved by about 29% and 60% respectively.