| 摘要 |
PROBLEM TO BE SOLVED: To obtain an echo canceller in which, even if a filter coefficient of a memory for adaptation is substituted by a save value, the value does not have discontinuity at the moment of the substitution and no abnormal noise is generated. SOLUTION: The canceller is provided with a memory 10 for adaptation for storing a coefficient for adaptation updated from a transmission signal and a residual signal by using a algorithms, a save memory 13 for storing the filter coefficient of the memory for adaptation in parallel while the adaptation is judged to be appropriate, a coefficient substitution means 15 for controlling the suitability of updating the filter coefficient for adaptation of an adaptive filter based on the difference between the transmission signal level and the residual signal level, and an interpolation means 23 for comparing the values of the first and the second filter coefficients to interpolate them. When the means 15 controls so that the value of the first filter coefficient is substituted by the value of the second filter coefficient because the adaptation is not appropriate, the means 23 interpolates at the prescribed number of timings and update them so that the values of the first and second filter coefficients can have continuous values.
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