| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a noise reduction device that can reduce the noise diffusing from a noise source in a wide range. <P>SOLUTION: The Noise emitted from the noise source is collected by a sensor microphone to generate acoustic signals, the acoustic signals are amplified by a microphone amplifier and reduction signals for reducing noise are generated by an inverse filter DSP. The reduction signals are inputted to each delay circuit and are delayed by each delay time set according to the arrangement order of a corresponding speaker 12, and the delayed signals are outputted to a speaker unit via a D/A converter and a power amplifier. Acoustic waves to be opposite phase waves to noise are emitted as control sound from respective speakers 12 of the speaker unit toward a control point, and the noise from the noise source is canceled in the wide range including the control point. <P>COPYRIGHT: (C)2012,JPO&INPIT</p> |
