| 摘要 |
PURPOSE:To complete converging operation in a short period by continuing the converging operation as to a signal series fetched during a unidirectional talking section also for a non-sound section and a bidirectional talking section. CONSTITUTION:A power detecting comparator 1 compares a transmission side power and a receiving side power in a signal from an echo path 11 and divides the talking section into the non-sound section, the unidirectional talking section and the bidirectional talking section. An operating mode deciding circuit 4 designates the repetitive mode in case of the non-sound section and the bidirectional talking section and transfers a talking signal to a receiving signal register 2 and an echo signal register 3. The data in the register 2 is applied with convoluting integration 6 by an operating equation stored in an estimate impulse response circuit 7, the data in the register 3 is compared by an operating circuit 8, and the residual is fed to a tap coefficient correcting circuit 10 to correct the next coefficient and this operation is repeated. The converging operation is performed in the repetitive mode in succession to the converging operation of the normal mode of the unidirectional talking section, allowing to reduce the converging time. |
