Patent ID: 8280037

Claim:
An echo canceller including an adaptive filter (ADF) for utilizing a far-end input signal to generate a pseudo-echo signal, and an echo suppression circuit for using the pseudo-echo signal to suppress an echo component included in a near-end input signal, comprising: an ACANC (Amounts of echo CANCellation) calculator operative in response to the near-end input signal inputted to said echo suppression circuit and an output signal outputted from said echo suppression circuit for finding an average value of an amount of echo cancellation for a predetermined period to update the average value of the amount of echo cancellation accordingly, and detecting a convergence state of said adaptive filter to find the amount of echo cancellation for a convergence period in the convergence state of said adaptive filter; and a coefficient selector operative in response to a detection signal of the convergence state of said adaptive filter being received from said ACANC calculator for finding a power ratio of a sum total of power of all tap coefficients held by said adaptive filter and a partial total of power of tap coefficients not to be assigned to taps among the tap coefficients of said adaptive filter, and determining an effective number of taps useful for suppressing an echo component on a basis of the amount of echo cancellation for the convergence period and the power ratio, said adaptive filter updating the effective number of taps determined by said coefficient selector.