Adjustable filter for differential microphones
First Claim
1. A method for providing a differential microphone with a desired frequency response, the differential microphone coupled to a filter having a frequency response which is adjustable, the method comprising the steps of:
- receiving one or more output signals from the differential microphone;
determining a distance between the differential microphone and a source of sound based on the received one or more output signals;
determining a filter frequency response, based on the determined distance, to provide the differential microphone with the desired response; and
adjusting the filter to exhibit the determined response.
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Accused Products
Abstract
A method and apparatus for providing a differential microphone with a desired frequency response are disclosed. The desired frequency response is provided by operation of a filter, having an adjustable frequency response, coupled to the microphone. The frequency response of the filter is set by operation of a controller, also coupled to the microphone, based on signals received from the microphone. The desired frequency response may be determined based upon the distance between the microphone and a source of sound, and may comprise both a relative frequency response and absolute output level. The frequency response of the filter may comprise the substantial inverse of the frequency response of the microphone to provide a flat response. Furthermore, the filter may comprise a Butterworth filter.
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Citations
38 Claims
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1. A method for providing a differential microphone with a desired frequency response, the differential microphone coupled to a filter having a frequency response which is adjustable, the method comprising the steps of:
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receiving one or more output signals from the differential microphone; determining a distance between the differential microphone and a source of sound based on the received one or more output signals; determining a filter frequency response, based on the determined distance, to provide the differential microphone with the desired response; and adjusting the filter to exhibit the determined response. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. An apparatus for providing a cardioid microphone with a desired frequency response, the apparatus comprising:
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an adjustable low-pass filter, coupled to the cardioid microphone; and a controller, coupled to the cardioid microphone and the low-pass filter, for adjusting the low-pass filter to provide the cardioid microphone with the desired response based on one or more signals received from the cardioid microphone.
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13. An apparatus for providing a differential microphone with a desired frequency response, the apparatus comprising:
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an adjustable filter, coupled to the differential microphone; and a controller, coupled to the differential microphone and the filter for determining a distance between the differential microphone and a source of sound based on one or more output signals received from the microphone and for adjusting the filter to provide the differential microphone with the desired response. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 36)
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24. A microphone system comprising:
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a differential microphone for providing one or more output signals; a filter, coupled to the differential microphone and having a frequency response which is adjustable, for filtering the output signals; and a controller, coupled to the differential microphone and the filter, for determining a distance between the differential microphone and a source of sound based on the one or more output signals received from the differential microphone and for adjusting the frequency response of the filter based on the determined distance to provide a desired frequency response for the system. - View Dependent Claims (25, 37)
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26. A communication device comprising:
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a differential microphone for providing one or more output signals; a filter, coupled to the differential microphone and having a frequency response which is adjustable, for filtering the output signals; and a controller, coupled to the differential microphone and the filter, for determining a distance between the differential microphone and a source of sound based on the one or more output signals received from the differential microphone and for adjusting the frequency response of the filter based on the determined distance to provide a desired frequency response for the system. - View Dependent Claims (27, 38)
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28. A method for providing a differential microphone with a desired frequency response, the differential microphone coupled to a filter having a frequency response which is adjustable, the method comprising the steps of:
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receiving one or more output signals from the differential microphone; determining a filter frequency response based on the received one or more output signals to provide the differential microphone with the desired response, wherein the determined frequency response reflects a substantial inverse of the frequency response of the differential microphone; and adjusting the filter to exhibit the determined response.
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29. A method for providing a differential microphone with a desired frequency response, the differential microphone coupled to a Butterworth filter having a frequency response which is adjustable, the method comprising the steps of:
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receiving one or more output signals from the differential microphone; determining a Butterworth filter frequency response, based on the received one or more output signals, to provide the differential microphone with the desired response; and adjusting the Butterworth filter to exhibit the determined response.
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30. An apparatus for providing a differential microphone with a desired frequency response, the apparatus comprising:
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an adjustable filter, coupled to the differential microphone; and a controller, coupled to the differential microphone and the filter, for adjusting the filter to provide the differential microphone with the desired response based on one or more signals received from the differential microphone, the controller including a detector for determining average values of the one or more signals received from the differential microphone, and a divider for determining a ratio of average signal values.
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31. An apparatus for providing a differential microphone with a desired frequency response, the apparatus comprising:
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an adjustable filter, coupled to the microphone; and a controller, coupled to the microphone and the filter, for adjusting the filter to exhibit a frequency response based on one or more signals received from the differential microphone, which frequency response is a substantial inverse of the frequency response of the differential microphone, to provide the differential microphone with the desired response.
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32. An apparatus for providing a differential microphone with a desired frequency response, the apparatus comprising:
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an adjustable Butterworth filter, coupled to the microphone; and a controller, coupled to the microphone and the Butterworth filter, for adjusting the Butterworth filter to provide the differential microphone with the desired response based on one or more signals received from the differential microphone.
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33. An apparatus for providing a pressure differential microphone with a desired frequency response, the apparatus comprising:
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an adjustable low-pass filter, coupled to the pressure differential microphone; and a controller, coupled to the pressure differential microphone and the low-pass filter, for adjusting the low-pass filter to provide the pressure differential microphone with the desired response based on one or more signals received from the pressure differential microphone.
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34. An apparatus for providing a velocity differential microphone with a desired frequency response, the apparatus comprising:
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an adjustable high-pass filter, coupled to the velocity differential microphone; and a controller, coupled to the velocity differential microphone and the high-pass filter, for adjusting the frequency response of the high-pass filter to provide the velocity differential microphone with the desired response based on one or more signals received from the velocity differential microphone.
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35. An apparatus for providing a displacement differential microphone with a desired frequency response, the apparatus comprising:
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an adjustable high-pass filter, coupled to the displacement differential microphone; and a controller, coupled to the displacement differential microphone and the high-pass filter, for adjusting the frequency response of the high-pass filter to provide the displacement differential microphone with the desired response based on one or more signals received from the displacement differential microphone.
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Specification