Apparatus and method for matching the response of microphones in magnitude and phase
First Claim
1. A device for receiving an audible input comprising:
- a hearing aid housing;
a first microphone operably attached to the hearing aid housing and having an output responsive to the audible input;
a second microphone operably attached to the hearing aid housing and having an output responsive to the audible input;
a phase adjustment circuit responsive to the first microphone output and a rolloff control output for producing a compensated microphone output; and
a subtractor circuit responsive to the compensated microphone output and the second microphone output for generating the rolloff control output.
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Accused Products
Abstract
An apparatus is provided for matching the response of a pair of microphones. The two microphones provide a first and second output, respectively, in response to an audible input. The microphone outputs are subtract from each other to produce a gain control output for operably controlling the gain of the first microphone output, resulting in a gain compensated microphone output. A phase adjustment circuit also is provided responsive to the gain compensated microphone output and a rolloff control output for producing a matching output. The rolloff control output is generated by a phase difference subtractor circuit responsive to both the matching output and the second microphone output. Moreover, the output of at least one of the microphones has a resonance frequency that is shifted to a desired preselected frequency.
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Citations
10 Claims
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1. A device for receiving an audible input comprising:
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a hearing aid housing;
a first microphone operably attached to the hearing aid housing and having an output responsive to the audible input;
a second microphone operably attached to the hearing aid housing and having an output responsive to the audible input;
a phase adjustment circuit responsive to the first microphone output and a rolloff control output for producing a compensated microphone output; and
a subtractor circuit responsive to the compensated microphone output and the second microphone output for generating the rolloff control output. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A circuit for shifting the rolloff of a microphone comprising:
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an input terminal for receiving an output from the microphone;
an amplifier having an inverting input and an output;
a gain control circuit operably connected between the input terminal and the inverting input of the amplifier for adjusting the gain of the microphone output; and
a feedback circuit operably connected to the output of the amplifier and the inverting input, the feedback circuit including a feedback adjustment circuit responsive to a rolloff control output. - View Dependent Claims (10)
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Specification