Noise suppression system
First Claim
Patent Images
1. A personal noise cancellation system to reduce undesired noise for an individual which system comprises:
- (a) an acoustic structure intended to provide a localized zone of noise cancellation for a single individual with the acoustic structure in the vicinity of the individual;
(b) an acoustic actuator having an output to emit an audio cancellation signal in a direction towards the individual to reduce said undesired noise in response to a received electrical cancellation signal which acoustic actuator is supported by said acoustic structure;
(c) audio input means to sense undesired noise receivable by said individual and produce an output for cancellation; and
(d) a noise cancellation controller to receive the output of the audio input means and generate said electrical cancellation signal for the acoustic actuator;
wherein said audio input means comprises;
(i) an elongated audio input mixing chamber extending transversely of the direction of output of the acoustic actuator to average a plurality of audio input signals received therein;
(ii) an array of audio input points to said elongated audio input chamber which audio input points are distributed in said transverse direction of output of the acoustic actuator and are designed to receive audio input signals from said direction;
(ii) at least one microphone acoustically coupled to said elongated chamber to receive a mixed and averaged audio input therefrom; and
wherein said audio input chamber is substantially enclosed to shield its volume from said cancellation signal, is disposed around the acoustic actuator output and is cooperative therewith to define a cancellation region at a location removed from said audio input means in the direction towards the individual.
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Abstract
A noise cancellation system, comprising a symmetrical assembly of microphone inputs is disclosed. A controller receives the output of the microphone assembly and generates an electrical cancellation signal having a polarity opposite the polarity of a portion of a noise to be cancelled and a magnitude equal to the magnitude of the portion of the noise to be cancelled. An actuator receives the electrical cancellation signal and outputs an audio cancellation signal.
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Citations
39 Claims
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1. A personal noise cancellation system to reduce undesired noise for an individual which system comprises:
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(a) an acoustic structure intended to provide a localized zone of noise cancellation for a single individual with the acoustic structure in the vicinity of the individual; (b) an acoustic actuator having an output to emit an audio cancellation signal in a direction towards the individual to reduce said undesired noise in response to a received electrical cancellation signal which acoustic actuator is supported by said acoustic structure; (c) audio input means to sense undesired noise receivable by said individual and produce an output for cancellation; and (d) a noise cancellation controller to receive the output of the audio input means and generate said electrical cancellation signal for the acoustic actuator; wherein said audio input means comprises; (i) an elongated audio input mixing chamber extending transversely of the direction of output of the acoustic actuator to average a plurality of audio input signals received therein; (ii) an array of audio input points to said elongated audio input chamber which audio input points are distributed in said transverse direction of output of the acoustic actuator and are designed to receive audio input signals from said direction; (ii) at least one microphone acoustically coupled to said elongated chamber to receive a mixed and averaged audio input therefrom; and wherein said audio input chamber is substantially enclosed to shield its volume from said cancellation signal, is disposed around the acoustic actuator output and is cooperative therewith to define a cancellation region at a location removed from said audio input means in the direction towards the individual. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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24. A personal noise cancellation system to reduce undesired noise for an individual in the vicinity of nuclear magnetic resonance apparatus which system comprises:
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(a) an acoustic structure intended to provide a localized zone of noise cancellation for a single individual with the acoustic structure in the vicinity of the individual; (b) a magnetic loudspeaker actuator having an output to emit an audio cancellation signal in a direction towards the individual to reduce said undesired noise in response to a received electrical cancellation signal which loudspeaker actuator is supported by said acoustic structure; (c) audio input means to sense undesired noise receivable by said individual and produce an output for cancellation; and (d) a noise cancellation controller to receive the output of the audio input means and generate said electrical cancellation signal for the loudspeaker actuator; wherein said audio input means comprises; (i) an elongated audio input mixing chamber extending transversely of the direction of output of the loudspeaker actuator to average a plurality of audio input signals received therein; (ii) an array of audio input points to said elongated audio input chamber which audio input points are distributed in said transverse direction of output of the loudspeaker actuator and are designed to receive audio input signals from said direction; (ii) at least one microphone acoustically coupled to said elongated chamber to receive a mixed and averaged audio input therefrom; and wherein said audio input chamber is substantially enclosed to shield its volume from said cancellation signal, is disposed around the loudspeaker actuator output and is cooperative therewith to define a cancellation region at a location removed from said audio input means in the direction towards the individual wherein the microphone is located remotely from the audio input means and the audio input means comprises an extended tubular waveguide by means of which the microphone is acoustically coupled to the audio input means whereby the loudspeaker actuator can be removed to a remote position free of interference with the nuclear magnetic resonance apparatus.
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25. A seat equipped with a personal noise cancellation system to reduce undesired noise for an individual which system comprises:
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(a) a pair of acoustic structures one for each ear of the individual which acoustic structures are intended to provide a localized zone of noise cancellation with the acoustic structure in the vicinity of the individual; (b) a pair of acoustic actuators one for each ear of the individual said acoustic actuators each having an output to emit an audio cancellation signal in a direction towards the individual to reduce said undesired noise in response to a received electrical cancellation signal which acoustic actuator is supported by said acoustic structure; (c) audio input means associated with each acoustic actuator to sense undesired noise receivable by said individual and produce an output for cancellation; and (d) a noise cancellation controller to receive the output of the audio input means and generate said electrical cancellation signal for each acoustic actuator; wherein said audio input means comprises; (i) an annular audio input mixing chamber extending transversely of the direction of output of the acoustic actuator to average a plurality of audio input signals received therein; (ii) an array of audio input points arranged symmetrically around said annular audio input chamber which audio input points are distributed in said transverse direction of output of the acoustic actuator and are designed to receive audio input signals from said direction; (ii) at least one microphone acoustically coupled to said elongated chamber to receive a mixed and averaged audio input therefrom; and wherein said audio input chamber is substantially enclosed to shield its volume from said cancellation signal, is disposed around its associated acoustic actuator output and is cooperative therewith to define a cancellation region at a location removed from said audio input means in the direction towards the individual. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32, 33)
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34. A noise cancellation system to reduce undesired noise in a cancellation volume subject to repetitive and random noise comprising:
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(a) an acoustic actuator for outputting a directed audio cancellation signal to the cancellation volume to reduce said undesired noise in response to a received electrical cancellation signal; (c) audio input means to sense said undesired noise and produce an output for cancellation; and (d) a noise cancellation controller to receive the output of the audio input means and generate said electrical cancellation signal for the acoustic actuator; wherein said audio input means comprises; (i) an elongated audio input mixing chamber extending transversely of the direction of output of the acoustic actuator to average a plurality of audio input signals received therein said elongated chamber being capable of integrating and smoothing said inputs; (ii) an array of audio input points to said elongated audio input chamber which audio input points are distributed in said transverse direction of output of the acoustic actuator to receive audio input signals; and (iii) at least one microphone acoustically coupled to said elongated chamber to receive a mixed and averaged audio input therefrom; said audio input chamber being substantially enclosed to separate its volume from surrounding volumes whereby the presence of random noise derived components in said cancellation signal can be reduced. - View Dependent Claims (35)
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36. A personal noise cancellation system to reduce undesired noise for an individual which system comprises:
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(a) an acoustic structure intended to provide a localized zone of noise cancellation for a single individual with the acoustic structure in the vicinity of the individual; (b) an acoustic actuator for outputting an audio cancellation signal towards the individual to reduce said undesired noise in response to a received electrical cancellation signal which acoustic actuator is supported by said acoustic structure; (c) audio input means to sense undesired noise receivable by said individual and produce an output for cancellation; and (d) a noise cancellation controller to receive the output of the audio input means and generate said electrical cancellation signal for the acoustic actuator; wherein said audio input means comprises a plurality of noise-sensing devices at a plurality of points disposed around the acoustic actuator output and cooperative therewith to define a cancellation region at a location removed from said audio input means in a direction towards the individual. - View Dependent Claims (37, 38, 39)
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Specification