Self calibrating multi-element dipole microphone
First Claim
1. A microphone comprising:
- a first acoustic sensor having a first output;
a second acoustic sensor separated by a distance from the first acoustic sensor and having a second output;
a sound source acoustically coupled to the first and second acoustic sensors, the sound source including an input;
enclosed sound conducting channels spanning continuously from the sound source to terminate at each of the first and second acoustic sensors, the enclosed sound conducting channels forming continuous acoustic transmission paths from the sound source to the first and second acoustic sensors;
a processor electrically coupled to the input, the first output, and the second output, the processor being configured to activate the sound source to produce an acoustic calibration signal, the acoustic transmission paths conveying a respective portion of the acoustic calibration signal to each of the first and second acoustic sensors, the processor further configured to receive a first output and a second output from the respective acoustic sensors in response to the respective portions acoustic calibration signal; and
the processor configured for determining one or more correction factors based on the received first and second outputs.
1 Assignment
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Accused Products
Abstract
A self calibrating dipole microphone formed from two omni-directional acoustic sensors. The microphone includes a sound source acoustically coupled to the acoustic sensors and a processor. The sound source is excited with a test signal, exposing the acoustic sensors to acoustic calibration signals. The responses of the acoustic sensors to the calibration signals are compared by the processor, and one or more correction factors determined. Digital filter coefficients are calculated based on the one or more correction factors, and applied to the output signals of the acoustic sensors to compensate for differences in the sensitivities of the acoustic sensors. The filtered signals provide acoustic sensor outputs having matching responses, which are subtractively combined to form the dipole microphone output.
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Citations
23 Claims
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1. A microphone comprising:
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a first acoustic sensor having a first output; a second acoustic sensor separated by a distance from the first acoustic sensor and having a second output; a sound source acoustically coupled to the first and second acoustic sensors, the sound source including an input; enclosed sound conducting channels spanning continuously from the sound source to terminate at each of the first and second acoustic sensors, the enclosed sound conducting channels forming continuous acoustic transmission paths from the sound source to the first and second acoustic sensors; a processor electrically coupled to the input, the first output, and the second output, the processor being configured to activate the sound source to produce an acoustic calibration signal, the acoustic transmission paths conveying a respective portion of the acoustic calibration signal to each of the first and second acoustic sensors, the processor further configured to receive a first output and a second output from the respective acoustic sensors in response to the respective portions acoustic calibration signal; and the processor configured for determining one or more correction factors based on the received first and second outputs. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A headset comprising:
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a first acoustic sensor having a first output; a second acoustic sensor separated by a distance from the first acoustic sensor and having a second output; a boom configured to hold the first acoustic sensor and the second acoustic sensor along an axis; a sound source acoustically coupled to the first and second acoustic sensors by enclosed sound conducting channels spanning continuously from the sound source to terminate at each of the first and second acoustic sensors, the enclosed sound conducting channels forming continuous acoustic transmission paths from the sound source to the first and second acoustic sensors, the sound source including an input; and a processor electrically coupled to the input, the first output, and the second output, the processor being configured to activate the sound source to produce an acoustic calibration signal that is conveyed by the acoustic transmission paths to the respective acoustic sensors, and further configured to receive a first output and a second output from the respective acoustic sensors in response to the acoustic calibration signal; and the processor configured for determining one or more correction factors based on the received first and second outputs. - View Dependent Claims (11, 12, 13, 14)
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15. A method of matching a pair of acoustic sensors forming a dipole microphone, the method comprising:
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generating an acoustic calibration signal with a sound source; transmitting the acoustic calibration signal to first and second acoustic sensors on continuous acoustic transmission paths formed by enclosed sound conducting channels spanning continuously from the sound source to terminate at each of the first acoustic sensor and the second acoustic sensor; measuring a response of the first acoustic sensor to the acoustic calibration signal; measuring a response of the second acoustic sensor to the acoustic calibration signal; determining one or more correction factors based on the responses of the first and second acoustic sensors to the acoustic calibration signal; and applying the one or more correction factors to signals produced by the first and second sensors so that the responses of the first and second sensors are matched. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23)
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Specification