Patent ID: 6330336
Filing Date: 2001-12-11
Classification: G10K

Abstract:
An active silencer comprising noise input means for obtaining a noise signal from noise generated by a noise source, signal processing means for converting the noise signal obtained by said noise input means into the signal waveform having the same amplitude as that of the noise waveform and inverse phase thereto propagated from said noise source, and a secondary sound source speaker for radiating the signal converted by said signal processing means as the sound wave in order to cause the noise from the noise source and the sound wave radiated from said secondary sound source speaker to be interfered with each other at a preset silencing point, wherein said signal processing means further comprising:pseudo space transmitting signal processing means for converting the noise signal obtained by said noise input means into the signal having the same amplitude characteristic as the frequency response characteristic of the sound wave up to said silencing point from said noise source and the phase characteristic delayed by a first predetermined amount (td-tp) for said frequency response characteristic; andpseudo inverse filter signal processing means for converting the signal converted by said pseudo space transmitting signal processing means into the signal having the amplitude characteristic which is the inverse of the frequency response characteristic of the sound wave up to the silencing point through said noise input means, said secondary sound source speaker, and the space from said secondary sound source speaker to said silencing point and also having the phase characteristic delayed by a second predetermined amount (tp) from the positively or negatively inverted phase for the frequency response characteristic of the sound wave.