| 摘要 |
PURPOSE:To attain the estimate of an echo path characteristic with high accuracy and the production of a pseudo echo signal and to simplify the constitution of the device by deciding independently the timing between the cancelling processing of an echo signal and the fetch of a data required for the correction of a tap coefficient. CONSTITUTION:Convolutional integration between data Xj-1, Xj-2-Xj-n and tap coefficients h1, h2-hn is attained at multipliers 161, 162-16n and an adder 17 and the result of convolutional integration is obtained as a pseudo echo signal Y. On the other hand, components being a frequency fc or over are eliminated from an output signal at a receiving end of a hybrid circuit 3 via an LPF 18 and sampled and held at an SH19. Then, a residual signal obtained by a subtractor 21 is multiplied with a prescribed coefficient alpha via a coefficient device 22, and applied to multiliers 231, 232-23n and stored to a tap coefficient resistor 15 as new tap coefficients. |
