The multiple filter processes which do the low-pass filter treatment where each cutoff frequency differs

摘要

PROBLEM TO BE SOLVED: To simulate physical characteristics of a Cds coupler used for a compressor of an analog circuit, an audio signal effector of another analog circuit, etc in a digital circuit.;SOLUTION: Results obtained by filtering an input signal through a plurality of low-pass digital filters 110, 120, and 130 differing in cutoff frequency are synthesized to simulate input/output characteristics of the Cds coupler. An amplifier 111 and an adder 113 increase the gain of an amplifier 114 and increase the cutoff frequency of the low-pass filter 110 as the input signal has a higher level. Consequently, physical characteristics of the Cds coupler that quickly follow up a rise of the input signal and gradually decrease in output level when the input signal falls are faithfully simulated.;COPYRIGHT: (C)2005,JPO&NCIPI