| 摘要 |
PURPOSE:To eliminate a sound efficiently and expand the sound elimination range by reducing the limitations of hardware and removing crosstalk from other systems. CONSTITUTION:The signal of a microphone 1 which detects a noise from a noise source is processed by A-FIRs 11a and 11b and controlled by FIRs 3a and 3b as FIR filters. Speakers 6a and 6b output playback sounds with the outputs of the A-FIRs 11a and 11b. Subtracters 12a and 12b subtract the outputs of the FIRs 13a and 13b from the output of the microphone 4 which detects a noise at a listening point. Then LMSs 5a and 5b as coefficient update devices calculate control signals for updating the coefficients of the A-FIRs 11a and 11b with the outputs of the subtracters 12a and 12b and FIRs 3a and 3b. Adaptive control is performed with the control signals so as to cancel noises of the A-FIRs 11a and 11b, and playback sounds are outputted by the speakers 6a and 6b respectively. |
