ECHO PREVENTING CIRCUIT, DIGITAL SIGNAL PROCESSING CIRCUIT, MEHTOD FOR SETTING FILTER COEFFICIENTS OF ECHO PREVENTING CIRCUIT, MEHTOD FOR SETTING FILTER COEFFICIENTS OF DIGITAL SIGNAL PROCESSING CIRCUIT, PROGRAM FOR SETTING FILTER COEFFICIENTS OF ECHO PREVENTING CIRCUIT, PROGRAM FOR SETTING FILTER COEFFICIENTS OF DIGITAL SIGNAL PROCESSING CIRCUIT

摘要

An object of the present invention is to effectively prevent an echo. And the input terminal, the first and second FIR, and the output signal of the first FIR is the first input signal from the input terminal the input output, or the output of the output signal is reflective type or, or the second input signal is and input and output terminals to be input, and a first subtraction circuit for subtracting the output signal of the second FIR from the first combined output signal and a second input signal of the FIR signal, the adaptive digital filter is the output signal of the first FIR is input, the output signal from the second subtraction circuit and a second and an output terminal to which the output signal is the output of the subtraction circuit, the adaptive digital filter, the output terminal for subtracting the output signal of the adaptive digital filter from the output signal of the first subtraction circuit It characterized in that the filter has a coefficient to be a signal other than the second input signal from the output signal of the first subtraction circuit to remove or attenuate a signal. ; Input terminal, the FIR filter, a subtraction circuit, a digital filter, the input and output terminals, the impulse response, converter DA, AD converter, DSP, earphone microphone