| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a low-cost and efficient active noise control apparatus and an active noise control system which control a level of noises emitted outside a casing from a plurality of opening parts. SOLUTION: The active noise control apparatus is provided with a plurality of opening parts 4a, 4b, noise detection microphones 6a, 6b which detect a noise in the vicinity of the opening edges 3a, 3b of ducts 5a, 5b, noise detection microphones 7a, 7b which detect noise in aural nulls P1, P2, noise reduction processing circuits 8a, 8b for generating a secondary sound having the same amplitude as the noise and a phase opposite to the noise in the aural nulls P1, P2 on the basis of detected noise, loudspeakers 9a, 9b which emit the above secondary sound to the aural nulls P1 and P2, a central adaptive arithmetic circuit 12 which performs adaptive arithmetic processing so that the noise level detected by the error detection microphones 7a, 7b become the minimum, and an error signal supervisory circuit 11 which monitors outputs from the error detection microphones 7a, 7b, and controls adaptive arithmetic processing about a calculation parameter used for noise reduction processing.</p> |
