| 摘要 |
PROBLEM TO BE SOLVED: To make it possible to demonstrate a noise reduction effect without an influence by fluctuation of a noise characteristic and a loudspeaker transfer function in a feedback type active noise control device which offsets noise with control sound of an opposite phase to the noise. SOLUTION: This active noise control device is constituted of a noise detecting microphone, a loudspeaker reverse characteristic correction means, a high frequency component attenuation means, an invertible amplifier, and a loudspeaker for control sound, and is configured to operate, to variations of the noise characteristic, by automatically changing a cut-off frequency of the high frequency component attenuation means according to the variations of the noise characteristic detected by the noise detecting microphone or the like, and to operate, to variations of the loudspeaker transfer function, by automatically changing the loudspeaker reverse characteristic correction means so that an open loop transfer function characteristic does not differ from a designed characteristic. Thus, the noise reduction effect can be obtained continuously. COPYRIGHT: (C)2005,JPO&NCIPI |
