| 摘要 |
PURPOSE:To reduce noises generated by a noise source by updating the filter coefficient of an adaptive filter so that noises at an observation position are minimum. CONSTITUTION:Noise generation state detecting means detect the noise generation states of plural noise sources and their detected values are inputted as reference signals to adaptive filters which are arranged individually as many as control sound sources. The outputs of the adaptive filters are added in control sound source units by a control sound source driving means and supplied to the control sound sources, which therefore generate control sounds based on the driving commands. At this time, a filter coefficient update means the updates the filter coefficients of the adaptive filters according to the detected values of residual noises at the observation position by residual noise detecting means and the detected values of the noise generation state detecting means so that the noises at the observation position become minimum. Consequently, even when there are plural noise sources, the noises at the observation position can accurately be reduce by interferring with the control sounds. |
