| 摘要 |
PCT No. PCT/FR96/00508 Sec. 371 Date Oct. 3, 1997 Sec. 102(e) Date Oct. 3, 1997 PCT Filed Apr. 3, 1996 PCT Pub. No. WO96/31872 PCT Pub. Date Oct. 10, 1996A selected electrical signal is first applied to the input of a source (30) to determine at least the impulse response (H), over a predetermined time, between the source output and the input of sensors (20). The values of the active cancellation control signal are determined in real time according to a predetermined law established in accordance with the previously determined impulse response (H), whereby the energy of the output signal from the sensors is minimised. The acoustic structure (2) is arranged so that the space (534) containing the sensors (20) and the source (30) is invariant at least during the determination of the active cancellation control signal and in the presence of a person, whereby the impulse response (H) between the output of the source (30) and the input of the sensors (20) may remain invariant. |
