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US5473701A
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Adaptive microphone array
Assignee: Adaptive Sonics LLC
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Filing: 1993-11-05
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Granted: 1995-12-05
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Expires: 2013-11-05
Abstract
Abstract The present invention is directed to a method of apparatus of enhancing the signal-to-noise ratio of a microphone array. The array includes a plurality of microphones and has a directivity pattern which is adjustable based on one or more parameters. The parameters are evaluated so as to realize an angular orientation of a directivity pattern null. This angular orientation of the directivity pattern null reduces microphone array output signal level. Parameter evaluation is performed under a constraint that the null be located within a predetermined region of space. Advantageously, the predetermined region of space is a region from which undesired acoustic energy is expected to impinge upon the array, and the angular orientation of a directivity pattern null substantially aligns with the angular orientation of undesired acoustic energy. Output signals of the array microphones are modified based on one or more evaluated parameters. An array output signal is formed based on modified and unmodified microphone output signals. The evaluation of parameters, the modification of output signals, and the formation of an array output signal may be performed a plurality of times to obtain an adaptive army response. Embodiments of the invention include those having a plurality of directivity patterns corresponding to a plurality of frequency subbands. Illustratively, the array may comprise a plurality of cardioid sensors.
Inventors
- 👤 Juergen Cezanne
- 👤 Gary W. Elko
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 19:15
CPC Classifications
H; H04; H04R; H04R3/00; H04R3/005; H04R1/00; H04R1/20; H04R1/32; H04R1/40; H04R1/406; H04R2430/00; H04R2430/20; H04R2430/21
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
162 words
A method of enhancing the signal-to-noise ratio of a microphone array, the array including a plurality of microphones and having a directivity pattern, the directivity pattern of the array being adjustable based on one or more parameters, the method comprising the steps of: a. evaluating one or more parameters to realize an angular orientation of a directivity pattern null, which angular orientation reduces microphone array output signal level in accordance with a criterion, said evaluation performed under a constraint that the null be precluded from being located within a predetermined region of space which comprises a range of directions about the array, which range reflects a predetermined directional variability of the desired acoustic energy with respect to the array; b. modifying output signals of one or more microphones of the array based on the one or more evaluated parameters; and c. forming an array output signal based on one or more modified output signals and zero or more unmodified microphone output signals.
Claim 2
Independent Claim
162 words
A method of enhancing the signal-to-noise ratio of a microphone array, the array including a plurality of microphones and having a directivity pattern, the directivity pattern of the array being adjustable based on one or more parameters, the method comprising the steps of: a. evaluating one or more parameters to realize an angular orientation of a directivity pattern null, which angular orientation reduces microphone array output signal level in accordance with a criterion, said evaluation performed under a constraint that the null be precluded from being located within a predetermined region of space which comprises a range of directions about the array, which range reflects a predetermined directional variability of the desired acoustic energy with respect to the array; b. modifying output signals of one or more microphones of the array based on the one or more evaluated parameters; and c. forming an array output signal based on one or more modified output signals and zero or more unmodified microphone output signals.
Claim 3
Dependent Claim
23 words
The method of claim 1 wherein steps a, b, and c, are performed a plurality of times to obtain an adaptive array response.
Claim 4
Dependent Claim
23 words
The method of claim 1 wherein a region of space other than the predetermined region of space includes sources of undesired acoustic energy.
Claim 5
Dependent Claim
28 words
The method of claim 1 wherein undesired acoustic energy impinges on the array from a direction within a region of space other than the predetermined region of space.
Claim 6
Dependent Claim
33 words
The method of claim 1 wherein the array has a plurality of directivity patterns corresponding to a plurality of frequency subbands, one or more of the plurality of directivity patterns including a null.
Claim 7
Dependent Claim
51 words
The method of claim 5 further comprising the step of forming a plurality of subband microphone output signals based on an output signal of a microphone of the array, wherein the step of modifying output signals comprises modifying the subband microphone output signals based on the one or more evaluated parameters.
Claim 8
Dependent Claim
14 words
The method of claim 1 wherein the array comprises a plurality of cardioid sensors.
Claim 9
Dependent Claim
61 words
The method of claim 7 wherein the plurality of cardioid sensors comprises a foreground cardioid sensor and a background cardioid sensor and wherein the step of evaluating comprises determining a parameter reflecting a ratio of (i) a product of output signals of the foreground and background cardioid sensors to (ii) the square of the output signal of the background cardioid sensor.
Claim 10
Dependent Claim
41 words
The method of claim 7 wherein the plurality of cardioid sensors comprises a foreground cardioid sensor and a background cardioid sensor and wherein the step of evaluating comprises determining a scale factor for an output signal of the background cardioid sensor.
Claim 11
Dependent Claim
26 words
The method of claim 9 wherein the scale factor is determined based on an output signal of the background cardioid sensor and the array output signal.
Claim 12
Independent Claim
165 words
An apparatus for enhancing the signal-to-noise ratio of a microphone array, the array including a plurality of microphones and having a directivity pattern, the directivity pattern of the array being adjustable based on one or more parameters, the apparatus comprising: a. means for evaluating one or more parameters to realize an angular orientation of a directivity pattern null, which angular orientation reduces microphone array output signal level in accordance with a criterion, said evaluation performed under a constraint that the null be precluded from being located within a predetermined region of space which comprises a range of directions about the array which range reflects a predetermined directional variability of the desired acoustic energy with respect to the array; b. means for modifying output signals of one or more microphones of the array based on the one or more evaluated parameters; and c. means for forming an array output signal based on one or more modified output signals and zero or more unmodified microphone output signals.
Claim 13
Independent Claim
165 words
An apparatus for enhancing the signal-to-noise ratio of a microphone array, the array including a plurality of microphones and having a directivity pattern, the directivity pattern of the array being adjustable based on one or more parameters, the apparatus comprising: a. means for evaluating one or more parameters to realize an angular orientation of a directivity pattern null, which angular orientation reduces microphone array output signal level in accordance with a criterion, said evaluation performed under a constraint that the null be precluded from being located within a predetermined region of space which comprises a range of directions about the array which range reflects a predetermined directional variability of the desired acoustic energy with respect to the array; b. means for modifying output signals of one or more microphones of the array based on the one or more evaluated parameters; and c. means for forming an array output signal based on one or more modified output signals and zero or more unmodified microphone output signals.
Claim 14
Dependent Claim
23 words
The apparatus of claim 11 wherein a region of space other than the predetermined region of space includes sources of undesired acoustic energy.
Claim 15
Dependent Claim
28 words
The apparatus of claim 11 wherein undesired acoustic energy impinges on the array from a direction within a region of space other than the predetermined region of space.
Claim 16
Dependent Claim
33 words
The apparatus of claim 11 wherein the array has a plurality of directivity patterns corresponding to a plurality of frequency subbands, one or more of the plurality of directivity patterns including a null.
Claim 17
Dependent Claim
52 words
The apparatus of claim 14 further comprising means for forming a plurality of subband microphone output signals based on an output signal of a microphone of the array, wherein the means for modifying output signals comprises means for modifying the subband microphone output signals based on the one or more evaluated parameters.
Claim 18
Dependent Claim
14 words
The apparatus of claim 14 wherein the means for evaluating comprises a polyphase filterbank.
Claim 19
Dependent Claim
17 words
The apparatus of claim 11 wherein the means for modifying comprises a means for performing fast convolution.
Claim 20
Dependent Claim
14 words
The apparatus of claim 11 wherein the array comprises a plurality of cardioid sensors.
Claim 21
Dependent Claim
63 words
The apparatus of claim 18 wherein the plurality of cardioid sensors comprises a foreground cardioid sensor and a background cardioid sensor and wherein the means for evaluating comprises means for determining a parameter reflecting a ratio of a (i) product of output signals of the foreground and background cardioid sensors to (ii) the square of the output signal of the background cardioid sensor.
Claim 22
Dependent Claim
43 words
The apparatus of claim 18 wherein the plurality of cardioid sensors comprises a foreground cardioid sensor and a background cardioid sensor and wherein the means for evaluating comprises means for determining a scale factor for an output signal of the background cardioid sensor.
Claim 23
Dependent Claim
26 words
The apparatus of claim 18 wherein the scale factor is determined based on an output signal of the background cardioid sensor and the array output signal.
Claim 24
Dependent Claim
16 words
The apparatus of claim 11 wherein the array comprises a cardioid sensor and a dipole sensor.
Claim 25
Dependent Claim
16 words
The apparatus of claim 11 wherein the array comprises a omnidirectional sensor and a dipole sensor.
References Cited (Backward Citations)
US4536887A
Cited
US4485484A
Cited
US4653102A
Cited
US4802227A
Cited
US4956867A
Cited
US5267320A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1998-12-04 | 1999-06-05 | 1999-12-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-12-04 | 2003-06-05 | 2003-12-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-12-04 | 2007-06-05 | 2007-12-05 | $7700.00 | Window Closed / Lapsed |