| 摘要 |
PURPOSE:To obtain at a low cost an echo canceller for showing good characteristics even at the time of a superposed call and at the time of a noise variation by setting automatically a quasi-optimum step gain based on the optimum identifying method using a low of causualty. CONSTITUTION:The contents of a receiving side input signal storage register 15, and the contents of a register 27 for storing an estimated value of an extended impulse response of an echo pulse are convoluted by using a convolutional operator 28, and a pseudo echo signal is generated. A transmitting side output signal is generated by subtracting this pseudo echo signal from a transmitting side input signal by using a subtractor 29. Subsequantly, in an extended impulse response correcting device 32, an estimated extended impulse response is corrected, based on the contents of a register 26, the contents of the register 27, the transmitting side output signal, a time average value of a power of the transmitting side output signal being an output of a time average device 31, and an estimated value of an identifying error being an output of an identifying error estimating device 30, and the contents of the register 27 are updated. |
