| 摘要 |
<P>PROBLEM TO BE SOLVED: To calculate tap coefficient parts acting for an actual echo elimination so as to select only the part to enable the part to function as an adaptive filter and to reduce the number of taps without deteriorating the performance for eliminating echo. <P>SOLUTION: In the echo canceller, an echo component elimination means eliminates an echo signal using a pseudo-echo signal from the adaptive filter, an average value of an amount of echo cancellation for a prescribed period is determined on the basis of an input signal and an output signal of an echo component elimination means, a convergence state of the adaptive filter is detected, a power ratio of the sum total of power of all tap coefficients held by the adaptive filter and a partial total of power of tap coefficients not to be assigned to taps among the tap coefficients of the adaptive filter at the convergence state of the adaptive filter is determined, the effective number of taps useful for eliminating an echo component is decided on the basis of the amount of echo cancellation in the convergence period and the power ratio, and the adaptive filter updates only the effective number of taps decided by the coefficient selector. <P>COPYRIGHT: (C)2011,JPO&INPIT |
