PURPOSE: To silence only the noise to be silenced in the room, and to improve responsiveness without performing convolution arithmetic or transmission function estimation.
CONSTITUTION: This noise reduction device is provided with a sound detecting means (M1) to detect sounds generated by a noise source (engine 12) or signals corresponding to sounds, frequency band deciding means (PP, SCF 1) to decide a frequency band corresponding to noise among the sounds generated by the noise source or the signals corresponding to the sounds, first frequency selecting means (SCF 1) to extract only the set frequency band among the sounds or the signals detected by the sound detecting means, and reverse phase sound applying means (BBD 1, A1, SP, M2, SCF 11 and MPU) to generate the reverse phase sounds of the signals passed through the first frequency selecting means.
UMEBAYASHI KAZUYUKI
SATO KAZUO
SHINSANGYO KAIHATSU KK