ACTIVE NOISE CONTROL APPARATUS
First Claim
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1. An active noise control apparatus comprising:
- a control unit for generating a control signal for canceling out a noise in a passenger compartment of a vehicle;
a sound output device for outputting a canceling sound for canceling out said noise based on said control signal, into said passenger compartment; and
a canceling error signal detector for outputting a canceling error signal representing a canceling error sound between said noise and said canceling sound to said control unit;
wherein said control unit comprises;
an A/D converter for converting said canceling error signal from an analog signal into a digital signal;
an echo canceler for correcting said control signal and thereby generating a digital echo canceling signal based on a corrective value corresponding to transfer characteristics between said sound output device and said canceling error signal detector;
a subtractor for generating a first basic signal by subtracting said digital echo canceling signal from the digital canceling error signal;
a delay filter for generating a second basic signal by delaying said first basic signal by a time corresponding to a ¼
period of a resonant frequency determined by resonant characteristics of said passenger compartment;
a first filter for correcting said first basic signal thereby generating a first corrective signal;
a second filter for correcting said second basic signal thereby generating a second corrective signal;
an adder for generating the control signal by combining said first corrective signal and said second corrective signal; and
a D/A converter for converting said control signal from a digital signal into an analog signal and outputting the analog control signal to said sound output device.
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Abstract
A subtractor subtracts an echo canceling signal (Ĉ·y1(n−1)) from a canceling error signal (e(n)) to estimate the resonant noise (d(n)) to be silenced at a position of a microphone, and outputs a first basic signal (x1(n)) representing the estimated resonant noise d(n) as an input signal supplied to a controller. In the controller, a delay filter generates a second basic signal (x′(n)) by delaying the first basic signal (x1(n)) by a time value (Z−n) The controller generates a control signal (x(n)) based on the first basic signal (x(n)) and the second basic signal (x′(n)).
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Citations
15 Claims
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1. An active noise control apparatus comprising:
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a control unit for generating a control signal for canceling out a noise in a passenger compartment of a vehicle; a sound output device for outputting a canceling sound for canceling out said noise based on said control signal, into said passenger compartment; and a canceling error signal detector for outputting a canceling error signal representing a canceling error sound between said noise and said canceling sound to said control unit; wherein said control unit comprises; an A/D converter for converting said canceling error signal from an analog signal into a digital signal; an echo canceler for correcting said control signal and thereby generating a digital echo canceling signal based on a corrective value corresponding to transfer characteristics between said sound output device and said canceling error signal detector; a subtractor for generating a first basic signal by subtracting said digital echo canceling signal from the digital canceling error signal; a delay filter for generating a second basic signal by delaying said first basic signal by a time corresponding to a ¼
period of a resonant frequency determined by resonant characteristics of said passenger compartment;a first filter for correcting said first basic signal thereby generating a first corrective signal; a second filter for correcting said second basic signal thereby generating a second corrective signal; an adder for generating the control signal by combining said first corrective signal and said second corrective signal; and a D/A converter for converting said control signal from a digital signal into an analog signal and outputting the analog control signal to said sound output device. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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2. An active noise control apparatus comprising:
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a control unit for generating a control signal for canceling out a noise in a passenger compartment of a vehicle; a sound output device for outputting a canceling sound for canceling out said noise based on said control signal, into said passenger compartment; and a canceling error signal detector for outputting a canceling error signal representing a canceling error sound between said noise and said canceling sound to said control unit, wherein said control unit comprises; an A/D converter for converting said canceling error signal from an analog signal into a digital signal; an echo canceler for correcting said control signal and thereby generating a digital echo canceling signal based on a corrective value corresponding to transfer characteristics between said sound output device and said canceling error signal detector; a subtractor for generating a first basic signal by subtracting said digital echo canceling signal from the digital canceling error signal; a delay filter for generating a second basic signal by delaying said first basic signal by a predetermined time based on a resonant frequency determined by resonant characteristics of said passenger compartment; an adder for combining said first basic signal and said second basic signal into a combined signal; an amplitude adjuster for adjusting an amplitude of said combined signal with a predetermined gain to a predetermined magnitude, thereby generating said control signal; and a D/A converter for converting said control signal from a digital signal into an analog signal and outputting the analog control signal to said sound output device.
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Specification