AN ECHO CANCELLER FOR DECREASING A DETERIORATION FACTOR OF SPEECH QUALITY

摘要

The echo canceller of the present invention comprises a means for estimating an echo gain from a reception signal and a transmission signal; first level calculating means for calculating the power of the reception signal; second level calculating mean s For calculating the power of the transmission signal; echo gain estimating means for estimating an echo gain based on the power of the reception signal and the power of the transmission signal; and echo level estimating means for adding the estimated echo gain to the power of th e reception signal to obtain an estimated echo level, third level calculating means for calculating the power of a residual signal; and comparator means for comparing the estimated echo lev el with the power of the residual signal after the echo cancellation; wherein the echo o f the reception signal contained in the transmission signal is cancelled when said estimated echo level exceeds the value obtained by adding a margin to the power of the residual signal. T he various powers may be logarithmic values.