| 摘要 |
PURPOSE:To cancel echo sufficiently from an incoming reception signal, and to apply the device to double talk, by providing the 1st and the 2nd correcting circuits generating a control signal correcting the tap coefficient of a filter through the reception of an error signal. CONSTITUTION:An error signal used for the 1st tap coefficient correction circuit 9 is a signal being a result of subtraction of a virtual echo signal En of the 1st transversal filter 10 and a predictive transmission signal B'n of an opposing MODEM outputted from the 2nd transversal filter 13 from an incoming reception signal B'n+En incoming to the 1st substractor 7. To obtain the signal B'n, an output signal Bb of an MODEM reception discriminating circuit 5 is inputted to the 2nd transversal filter 13. The tap coefficient of the 2nd transversal filter 13 is corrected adaptively with the 2nd control signal of the 2nd tap coefficient correction circuit 12, i.e., the MRE method using the output signal of the 2nd subtractor 8 as an error signal. |
