Apparatus for reducing noise in space applicable to vehicle compartment
First Claim
1. An apparatus for reducing noises in a space, comprising:
- a) control sound source for generating a control sound to be interfered with the noises so as to reduce the noises at an evaluation area of the space;
b) first means for detecting a residual noise at a predetermined position of the space after the interference with the noises;
c) second means for detecting signals related to noise generating conditions of a plurality of noise sources;
d) third means for selecting either of first and second signal components from detected signals related to the noise generating conditions of said second means as a signal component predominant over the other signal component in the generating noises in the space, the first signal component having a relatively high auto-correlated function characteristic and the second signal component having a random characteristic;
e) an adaptive digital filter for adaptively filter processing a selected signal component output from said third means by means of adaptively determined filter coefficients and outputting a drive signal to drive said control sound source; and
f) fourth means for updating the predetermined filter coefficients using a control algorithm on the basis of the output signal from said second means and the selected signal component of said third means so as to reduce the output signal from the third means.
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Abstract
In an apparatus for reducing noises in a space, signals related to noise generating conditions of a plurality of noise sources are detected, a signal component of the detected signals is selected on the basis of determination of which signal component is predominant over the other signal component in the noises in the space, and the selected signal component is filtered through adaptively determined filter coefficients to output drive signals to control sound source, the filter coefficients being updated through a control algorithm so as to reduce a residual noise of a residual noise detector such as microphones. The signal components to be selected include a signal component having a relatively high auto-correlated function characteristic and a signal component having a random characteristic.
54 Citations
17 Claims
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1. An apparatus for reducing noises in a space, comprising:
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a) control sound source for generating a control sound to be interfered with the noises so as to reduce the noises at an evaluation area of the space; b) first means for detecting a residual noise at a predetermined position of the space after the interference with the noises; c) second means for detecting signals related to noise generating conditions of a plurality of noise sources; d) third means for selecting either of first and second signal components from detected signals related to the noise generating conditions of said second means as a signal component predominant over the other signal component in the generating noises in the space, the first signal component having a relatively high auto-correlated function characteristic and the second signal component having a random characteristic; e) an adaptive digital filter for adaptively filter processing a selected signal component output from said third means by means of adaptively determined filter coefficients and outputting a drive signal to drive said control sound source; and f) fourth means for updating the predetermined filter coefficients using a control algorithm on the basis of the output signal from said second means and the selected signal component of said third means so as to reduce the output signal from the third means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. An apparatus for reducing noises in a space, comprising:
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a) control sound source means for generating a control sound to be interfered with the noises at an evaluation area of the space so as to reduce the noises at the evaluation area; b) residual noise detecting means for detecting a residual noise at a predetermined position of the space after the interference with the noise; c) a single noise generating condition sensor which is so constructed as to detect signals related to noise generating conditions of a plurality of noise sources; d) signal component separating means for separating the detected signals from the noise generating condition sensor into both first and second signal components, said first signal component having a relatively high auto-correlated function characteristic and said second signal component having a random characteristic; e) separated signal component selecting means for selecting either first or second signal component which is predominant in the noises in the space over the other signal component; f) an adaptive digital filter which is so constructed as to adaptively filter process the selected signal component from the separated signal component selecting means through adaptively determined filter coefficients and to output a drive signal to drive the control sound source means; and g) an adaptive controller which is so constructed as to update the adaptively determined filter coefficients through a predetermined control algorithm on the basis of the output signal of the residual noise detecting means and selected signal component from said separated signal component selecting means to reduce the detected residual noise.
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Specification