FILTER CIRCUIT FOR NOISE CANCELLATION, NOISE REDUCTION SIGNAL PRODUCTION METHOD, AND NOISE-CANCELLATION SYSTEM

摘要

PPROBLEM TO BE SOLVED: To suppress influence due to digital delay to allow proper noise reduction, while taking into consideration advantages of digitization, with respect to a filter circuit for use in a noise-cancellation system. PSOLUTION: An analog path is provided which is used in the noise cancellation system and is connected, in parallel with a digital section comprising an ADC 121, a DSP/CPU (digital filter section) 122, and a DAC 123 and processes a noise signal in an analog filter 124 and then outputs the noise signal or outputs the noise signal, as it is. An analog noise reduction signal, produced by a digital section and an analog signal from the analog path are combined to produce a noise reduction signal that is used for noise reduction. PCOPYRIGHT: (C)2008,JPO&INPIT