Method and apparatus for performing noise cancelling and headphoning
First Claim
1. An open air composite transducer assembly for use in cancelling sound waves in an ear canal, comprising:
- a first input transducer for converting sound waves incident on a pickup surface of the first input transducer into corresponding input electrical signals, the pickup surface of the first input transducer facing in a first direction;
a second input transducer for converting sound waves incident on a pickup surface of the second input transducer into corresponding input electrical signals, the pickup surface of the second input transducer facing in a direction opposite said first direction;
an output transducer including a diaphragm for converting output electrical signals into corresponding sound waves which emanate from said diaphragm surface of the output transducer into said ear canal, the diaphragm surface facing in a direction opposite said first direction; and
a frame structure to which said first and second input transducers and said output transducer are fixed so that said pickup surfaces of said first and second input transducers and said diaphragm surface of said output transducer are in substantially the same plane.
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Accused Products
Abstract
A device for performing electroacoustic functions including noise cancellation, communication interface, and headphone functions. The device includes a composite transducer which is connected to a control unit. The composite transducer, which is adapted for use with the human ear, includes at least three transducers, oriented to be substantially coplanar to each other: two oppositely oriented input transducers for converting acoustic waves into electrical signals, and at least one output transducer oriented facing the ear for converting electrical signals into acoustic waves. The control unit includes circuitry for driving the output transducer based on electrical signals from the input transducers with an amplitude and phase to perform the noise cancellation, sound filtering, communication interface, and headphone functions. The input transducer which is oriented facing the ear picks up residual noise present in the ear canal which was not cancelled by the first input transducer to output transducer signal path due to non-ideal frequency and amplitude characteristics. The second input transducer supplies an electrical signal corresponding to the residual noise to the control circuitry to cancel the residual noise. Additionally, the path of acoustic energy from a noise source, through the composite transducer, and to the ear canal can be lengthened by the addition of a baffle around which the acoustic energy must travel.
68 Citations
20 Claims
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1. An open air composite transducer assembly for use in cancelling sound waves in an ear canal, comprising:
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a first input transducer for converting sound waves incident on a pickup surface of the first input transducer into corresponding input electrical signals, the pickup surface of the first input transducer facing in a first direction; a second input transducer for converting sound waves incident on a pickup surface of the second input transducer into corresponding input electrical signals, the pickup surface of the second input transducer facing in a direction opposite said first direction; an output transducer including a diaphragm for converting output electrical signals into corresponding sound waves which emanate from said diaphragm surface of the output transducer into said ear canal, the diaphragm surface facing in a direction opposite said first direction; and a frame structure to which said first and second input transducers and said output transducer are fixed so that said pickup surfaces of said first and second input transducers and said diaphragm surface of said output transducer are in substantially the same plane. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An electroacoustic device for cancelling sound waves in a ear canal, comprising:
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a first input transducer for converting sound waves incident on a pickup surface of the first input transducer into corresponding input electrical signals, the pickup surface of the first input transducer facing in a first direction; a second input transducer for converting residual sound waves from said ear canal which are incident on a pickup surface of the second input transducer into corresponding input electrical signals, the pickup surface of the second input transducer facing in a direction opposite said first direction; an output transducer including a diaphragm for converting output electrical signals into corresponding sound waves which emanate from said diaphragm surface of the output transducer into said ear canal, the diaphragm surface facing in a direction opposite said first direction; and a frame structure to which said first and second input transducers and said output transducer are fixed so that said pickup surfaces of said first and second input transducers and said diaphragm surface of said output transducer are in substantially the same plane; and a control means for receiving the electrical signals from the first input transducer and for generating a first component of the output electrical signals to the output transducer, the first component of the output electrical signals being substantially 180 degrees out of phase with respect to a frequency range of said sound waves incident on said pickup surface of said first input transducer, the control means also being for receiving the electrical signals from the second input transducer and for generating a second component of the output electrical signals to the output transducer, the second component of the output electrical signals being substantially 180 degrees out of phase with respect to said residual sound waves in the ear canal which are incident on said pickup surface of said second input transducer. - View Dependent Claims (9, 10, 11, 12, 13)
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14. A method for cancelling incoming noise entering an ear canal and for cancelling residual noise present in an ear canal, comprising the steps of:
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detecting the incoming noise with a first input transducer and generating an electrical signal indicative of the incoming noise; providing the electrical signal indicative of the incoming noise to an output transducer so that first acoustic waves are input into the ear canal that are phase shifted substantially 180 degrees with respect to the incoming noise, the first acoustic waves cancelling a component of said incoming noise which lies in a known frequency range within which said output transducer has a flat amplitude response; detecting said residual noise with a second input transducer and generating an electrical signal indicative of the residual noise; and providing the electrical signal indicative of the residual noise to said output transducer so that second acoustic waves are input into the ear canal that are phase shifted substantially 180 degrees with respect to the residual noise, the electrical signal indicative of the residual noise being filtered so that frequency components in said known frequency range are removed, the second acoustic waves cancelling a component of said incoming noise which lies outside said known frequency range. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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Specification