ECHO PREVENTION CIRCUIT, DIGITAL SIGNAL PROCESSING CIRCUIT, FILTER COEFFICIENT SETTING METHOD FOR ECHO PREVENTION CIRCUIT, FILTER COEFFICIENT SETTING METHOD FOR DIGITAL SIGNAL PROCESSING CIRCUIT, PROGRAM FOR SETTING FILTER COEFFICIENT OF ECHO PREVENTION CIRCUIT, AND PROGRAM FOR SETTING FILTER COEFFICIENT OF DIGITAL SIGNAL PROCESSING CIRCUIT

摘要

PROBLEM TO BE SOLVED: To provide an echo prevention circuit capable of effectively preventing echoes.;SOLUTION: The echo prevention circuit comprises: an input terminal to which a first input signal is given; a first FIR filter 4 and a second FIR filter 11 into which the first input signal is given; an input/output terminal to which an output signal of the first FIR filter is outputted or a second input signal is inputted; a subtracter circuit 9 that subtracts an output signal of the second FIR filter from a combined signal of the output signal of the first FIR filter and the second input signal; and an output terminal to which an output signal of the subtracter circuit is outputted. The first and the second FIR filters have such filter coefficients that the output signal through the output terminal has only the output signal from the first FIR filter removed or reduced.;COPYRIGHT: (C)2007,JPO&INPIT