JPS6430371A - Noise reducer - Google Patents

Abstract

PURPOSE:To sufficiently eliminate noises even in case of treating a signal whose noise signal level is not determined uniquely by detecting the noise signal level in a signal automatically, and making thus obtained noise signal level into an amplitude suppression level for an amplitude suppressor. CONSTITUTION:In addition to the constitution of a conventional noise reducer, the following two are provided: an absolute value converter 16 that converts an output signal 22 from a high-pass filter 12 to an absolute value signal 23, and a maximum value detector 17 that compares the signal 23 from the converter 16 with a prescribed reference value (b) and detects the local maximum value in a prescribed period of an absolute-value-converter-output signal in a value less than the reference value (b). As a result, the noise level of an input signal can be detected, and in accordance with thus detected noise level, the amplitude suppression level of the amplitude suppressor 13 is varied, and accordingly, noise can be sufficiently eliminated even no matter whatever noise level signals are inputted, furthermore, the lacking of the edge of a signal can be suppressed to the minimum.