Automatic calibrating apparatus and method for second-order gradient microphone
First Claim
1. An apparatus for calibrating a second-order gradient microphone including a pair of first-order gradient microphones disposed in a common housing along a common axis, the apparatus comprising:
- a transducer disposed in the housing equidistant acoustically from the first and the second one of the pair of first-order gradient microphones, the transducer arranged for generating a sound pressure for coupling through a port associated with the transducer to the first-order gradient microphones via a pair of ports, each one of the ports in the pair being respectively associated with one of the first-order gradient microphones.
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Accused Products
Abstract
An automatic calibration system for a second-order gradient microphone is provided to ensure optimum sensitivity balance between a pair of first-order gradient microphones mounted in a housing and forming the second-order gradient microphone. Automatic calibration is achieved through use of a transducer also mounted in the housing and located equidistant acoustically between the two first-order gradient microphones. Under the control of a computer, the transducer is directed to generated sound pressure which is used to calibrate the gain of amplifiers respectively associated with each one of the first-order gradient microphones for obtaining maximum directional sensitivity for a second-order directional response pattern. Such a system not only allows the use of inexpensive, non-matched microphones, but also obviates the need for factory calibration. Since the system is configurable to optimize itself automatically prior to use, calibration may be maintained regardless of aging, environmental stresses and parts replacement.
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Citations
22 Claims
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1. An apparatus for calibrating a second-order gradient microphone including a pair of first-order gradient microphones disposed in a common housing along a common axis, the apparatus comprising:
a transducer disposed in the housing equidistant acoustically from the first and the second one of the pair of first-order gradient microphones, the transducer arranged for generating a sound pressure for coupling through a port associated with the transducer to the first-order gradient microphones via a pair of ports, each one of the ports in the pair being respectively associated with one of the first-order gradient microphones. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An apparatus for calibrating a second-order gradient microphone including a plurality of first-order gradient microphones, each disposed in a common housing for receiving sound and for generating a respective output signal, the apparatus comprising:
a transducer disposed in the housing equidistant acoustically from the plurality of first-order gradient microphones, the transducer arranged for generating a sound pressure for coupling through a port associated with the transducer to the first-order gradient microphones via a plurality of ports, each one of the ports in the plurality being respectively associated with one of the first-order gradient microphones. - View Dependent Claims (10, 11, 12, 13)
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14. A method for calibrating a second-order gradient microphone including a pair of first-order gradient microphones disposed in a common housing along a common axis, the method comprising the steps of:
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generating a sound pressure by a transducer disposed in the housing equidistant acoustically from the first and the second one of the pair of first-order gradient microphones, the sound pressure being coupled through a port associated with the transducer to the first-order gradient microphones; and receiving the sound pressure from the transducer via a pair of ports, each one of the ports in the pair being respectively associated with one of the first-order gradient microphones. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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21. A microphone apparatus comprising:
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a housing; first and second first-order gradient microphones disposed in said housing along a common axis; and a transducer disposed in said housing, said housing having a transducer port and first and second microphone ports formed therein in such a way that sound pressure generated by said transducer is coupled through said transducer port to said first and second microphones via said first and second microphone ports, respectively, said transducer port being equidistant between said microphone ports. - View Dependent Claims (22)
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Specification