Active noise eliminating system
First Claim
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1. An active noise eliminating system, comprising:
- (a) means for detecting a residual noise signal;
(b) means for generating noise eliminating sound for interference with the residual noise;
(c) means for detecting a noise generating condition signal of a noise source;
(d) means for controlling a noise elimination signal applied to said noise eliminating sound generating means by calculating the noise elimination signal on the basis of the detected residual noise signal and the detected noise generating condition signal in accordance with a control algorithm including a transfer function between said noise eliminating sound generating means and said residual noise signal detecting means;
(e) divergence detecting means for directly detecting a divergence condition of said noise eliminating sound and generating a divergence indicating signal indicative thereof;
(f) test signal generating means, responsive to said divergence indicating signal generated by said divergence detecting means for generating a test signal for said noise eliminating sound generating means; and
(g) updating means responsive to said divergence indicating signal generated by said divergence detecting means for updating the transfer function between said noise eliminating sound generating means and said residual noise signal detecting means on the basis of the test signal whenever said sound divergence detecting means detects sound divergence, for prevention of noise divergence.
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Abstract
An active noise eliminating system comprises microphones for detecting residual noise, speakers for generating noise elimination sound for interference with the residual noise, a noise generating condition sensor for generating noise condition, a controller for generating noise elimination signals inputted to the speakers and determined by the detected residual noise signals and the detected noise condition signal in accordance with a control algorithm including transfer functions between the speakers and microphones respectively. The transfer functions are updated on the basis of a test signal generated when noise sound diverges.
131 Citations
17 Claims
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1. An active noise eliminating system, comprising:
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(a) means for detecting a residual noise signal; (b) means for generating noise eliminating sound for interference with the residual noise; (c) means for detecting a noise generating condition signal of a noise source; (d) means for controlling a noise elimination signal applied to said noise eliminating sound generating means by calculating the noise elimination signal on the basis of the detected residual noise signal and the detected noise generating condition signal in accordance with a control algorithm including a transfer function between said noise eliminating sound generating means and said residual noise signal detecting means; (e) divergence detecting means for directly detecting a divergence condition of said noise eliminating sound and generating a divergence indicating signal indicative thereof; (f) test signal generating means, responsive to said divergence indicating signal generated by said divergence detecting means for generating a test signal for said noise eliminating sound generating means; and (g) updating means responsive to said divergence indicating signal generated by said divergence detecting means for updating the transfer function between said noise eliminating sound generating means and said residual noise signal detecting means on the basis of the test signal whenever said sound divergence detecting means detects sound divergence, for prevention of noise divergence. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. An active noise eliminating system comprising
(a) means for detecting a residual noise signal; -
(b) means for generating noise eliminating sound for interference with the residual noise; (c) means for detecting a noise generating condition signal of a noise source; (d) means for controlling a noise elimination signal applied to said noise eliminating sound generating means by calculating the noise elimination signal on the basis of the detected residual noise signal and the detected noise generating condition signal in accordance with a control algorithm including a transfer function between said noise eliminating sound generating means and said residual noise signal detecting means; (e) divergence detecting means for detecting a divergence condition of said noise eliminating sound and generating a divergence indicating signal indicative thereof; (f) test signal generating means, responsive to said divergence indicating signal generated by said divergence detecting means for generating a test signal for said noise eliminating sound generating means; (g) updating means responsive to said divergence indicating signal generated by said divergence detecting means for updating the transfer function between said noise eliminating sound generating means and said residual noise signal detecting means on the basis of the test signal whenever said sound divergence detecting means detects sound divergence, for prevention of noise divergence, wherein said divergence detecting means comprises; (h) means disposed in the vicinity of said noise eliminating sound generating means, for detecting said noise eliminating sound outputted by said noise eliminating sound generating means; and (i) means for calculating a second transfer function, between a signal for activating said noise eliminating sound generating means and a signal outputted by said noise eliminating sound detecting means, and wherein said divergence detecting means operates for detecting a sound divergence on the basis of a change in phase of the calculated second transfer function.
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14. In an active noise eliminating system having a plurality of microphones for receiving residual noise, a plurality of speakers for generating noise eliminating sound for interference with the residual noise, noise generating condition sensor, a controller for generating noise elimination signals (ym) applied to the speaker and determined by adaptive controller coefficients (Wm |), residual noise signals (el) detected by the microphones, and a reference signal (X) detected by the noise generating condition sensor in accordance with a control algorithm including transfer functions (Clm) between the speakers and the microphones respectively, a method of updating the transfer functions (Clm), which comprises the steps of:
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(a) detecting whether the noise eliminating sound diverges or not; (b) generating a divergence detection signal when the noise eliminating sound diverges; (c) transmitting a test signal to the speakers in response to the divergence detection signal; (d) calculating the transfer functions (Clm)between the speakers and the microphones on the basis of the transmitted test signal; and (e) updating the transfer functions by the transfer functions calculated on the basis of the test signal. - View Dependent Claims (15, 16, 17)
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Specification