Degree of modulation detection method modulation degree detection circuit, and noise processing circuit,

摘要

PROBLEM TO BE SOLVED: To speedily detect variation from a low modulation factor to a high modulation factor and to make the quantity of variation in modulation factor after the variation to the high modulation factor is detected.;SOLUTION: A modulation factor detecting circuit includes an absolute value output circuit which outputs the absolute value of an audio signal, a modulation factor output circuit which outputs a larger value between the absolute value and a comparison value corresponding to a modulation factor which is output immediately before as a modulation factor, a delay circuit which delays the modulation factor output from the modulation factor output circuit by a specified time and outputs it as a second modulation factor, a comparing circuit which outputs a result of comparison between the first modulation factor as the modulation factor which is output from the modulation output circuit immediately before and the second modulation factor output from the delay circuit, and an output circuit which outputs, according to the comparison output from the comparing circuit, the first modulation factor as the comparison value to the modulation factor output circuit when the first modulation factor is larger than the second modulation factor and a value obtained by decreasing the first modulation factor as the comparison value to the modulation factor output circuit when the fist modulation factor is smaller than the second modulation factor.;COPYRIGHT: (C)2007,JPO&INPIT