| 摘要 |
PURPOSE:To cancel residual echo sufficiently at the point of time of the sampling of received data by supplying a residual signal at the point of time of sampling shown by a timing signal which is extracted from the sent signal of a subtracter to an adaptive filter which generates a pseudo echo signal and performing adaptive control over its response characteristics. CONSTITUTION:The adaptive filter 10 in an echo canceler 1 receives transmitted data and generates and sends the pseudo echo signal to the subtracter 11. The transmitted data, on the other hand, is sent from a hybrid circuit 20 to the opposite station, and sent to from the opposite station to the subtracter 11 together with the echo of the transmitted data from the transmitting station. The subtracter 11 subtracts the pseudo echo signal from the received signal and sends the signal of the subtraction result to a sample circuit 3 and an equalization decision part 5. The adaptive filter 10 correlates the transmitted data with the sent signal of the sample circuit 3 to correct a tap coefficient. Therefore, the amplitude of the residual echo contained in the sent signal of the subtracter 11 is suppressed sufficiently at the point of time of the sampling of the received data.
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