| 摘要 |
PROBLEM TO BE SOLVED: To provide a passive sound attenuation controller and a method that perform control for speedily suppressing an error and microphone sound pressure stably without dispersion. SOLUTION: The passive sound attenuation controller is equipped with a means 103 of generating a reference signal based upon a sound to be reduced, a means 105 of detecting the level value of the reference signal and the quantity of variation in level value, a means 105 of comparing the level variation quantity with a certain threshold range, an adaptive filter 104 whose filter coefficient is variable, a means 108 of stopping update of the filter coefficient of the adaptive filter when the level variation quantity is not within the threshold range, a means 109 of storing the filter coefficient each time the filter coefficient is updated, a means 104 of filtering the reference signal by using the stored filter coefficient to generate a control signal, a control sound source 102 of generating a control sound based upon the control signal, an error microphone 110 which detects composite sound pressure of the control sound and the sound to be reduced, and a means 111 of setting the filter coefficient based upon an error signal corresponding to the composite sound pressure and the signal obtained by filtering the control signal by the adaptive filter. COPYRIGHT: (C)2007,JPO&INPIT
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