The present invention relates a microphone array. More particularly, this invention relates to a system for providing unidirectional response.
For a more complete understanding of the disclosure, reference should be made to the following detailed description and accompanying drawings wherein:
While the present disclosure is susceptible to various modifications and alternative forms, certain embodiments are shown by way of example in the drawings and these embodiments will be described in detail herein. It will be understood, however, that this disclosure is not intended to limit the invention to the particular forms described, but to the contrary, the invention is intended to cover all modifications, alternatives, and equivalents falling within the spirit and scope of the invention defined by the appended claims.
The present invention is a system having a microphone array for providing a unidirectional response to an audio signal or sound wave. Referring to
In a third stage of the circuit 100, a bandpass filter 114 subtracts the signals from the front element 102 and the rear element 104, provides voltage gain, and also provides frequency filtering. In a fourth stage of the circuit 100, a converter 116 converts the output signal from the bandpass filter 114 to be compatible with a two-wire 12V connection. As, for example, would be typical for connection into an automotive system.
The front and rear microphone signals are switchable to allow reversal of the preferred direction for sound reproduction. A double-pole double-throw switch 105 controls which of the two microphone signals routes through the delay stage 112. The switch 105 may take many different forms. In a first embodiment, the switch 105 is in the form of a push-button type. In an example, the button may be pushed to alternate between receiving acoustic signals from a driver's side or passenger's side of a vehicle. In another embodiment, the switch 105 is voice-activated.
Prior art involving two-element first order unidirectional axial arrays required measures to compensate for amplitude and phase variability between microphone elements, such as, for example, electronic adjustments in gain and phase. Current MEMS microphones are typically well matched and do not require sorting or electronic measures to compensate for amplitude or phase variations between elements. Due to the restrictions of commercially available components, a switch of microphone inputs to achieve a reversed directional pattern in an array was not anticipated.
It is contemplated that other systems are possible according to the present invention, such as, for example, systems having “n” elements which are pointed in “n” directions. A switch may be provided for selecting between each of the “n” elements, or selecting between combinations of the elements. The present invention may allow, for example, switching of acoustic signal detection in a situation in which two passengers are sitting on opposite sides of an automobile (i.e., driver's side and passenger's side). A first passenger may be speaking into, for example, a cellular phone. A second passenger may speak directly into the array situated between the passengers, and via means of the switch, may prevent the acoustic signals generated from the first passenger to be detected to the extent that those signals interfere the second passenger's acoustic signals. Additional elements may improve signal to noise ratio; and allow for higher order arrays with tighter directional patterns.
It will be appreciated that numerous variations to the above-mentioned approaches are possible. Variations to the above approaches may, for example, include performing the above steps in a different order.
All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extend as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.
Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. It should be understood that the illustrated embodiments are exemplary only, and should not be taken as limiting the scope of the invention.
This patent claims benefit under 35 U.S.C. §119(e) to U.S. Provisional Application No. 61/250,693 entitled “Switchable Two-Element Directional Microphone System” filed Oct. 12, 2009 having Attorney Docket Number PO9016 the content of which is incorporated herein by reference in its entirety.
Number | Date | Country | |
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61250693 | Oct 2009 | US |