| 摘要 |
PROBLEM TO BE SOLVED: To prevent deterioration in echo cancel quantity by means of a slip phenomenon owing to a transmission speed difference between a reception side input signal and a transmission side input signal. SOLUTION: When a slipping signal is inputted to an echo canceler 10, Rin signal time and Sin signal time are shifted. Thus, the echo cancel quantity largely deteriorates. Counter circuits 27 and 28 are installed in Rin and Sin, which are the signal inputs of the echo canceler. The number of data of the signal input is counted. When the count results of the counter circuits 27 and 28 differ, a slip is generated. For compensating it, a shift operation circuit 30 shifts an H register 13 by one frame and the shift of Sin signal time and Rin signal time is compensated. Then, the echo canceler is continuously operated without deteriorating echo cancel quantity at all.
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