CA1236607A - Microphone arrangement - Google Patents
Microphone arrangementInfo
- Publication number
- CA1236607A CA1236607A CA000491313A CA491313A CA1236607A CA 1236607 A CA1236607 A CA 1236607A CA 000491313 A CA000491313 A CA 000491313A CA 491313 A CA491313 A CA 491313A CA 1236607 A CA1236607 A CA 1236607A
- Authority
- CA
- Canada
- Prior art keywords
- microphone
- transducers
- arrangement
- telephone set
- signal
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R3/00—Circuits for transducers, loudspeakers or microphones
- H04R3/005—Circuits for transducers, loudspeakers or microphones for combining the signals of two or more microphones
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04M—TELEPHONIC COMMUNICATION
- H04M1/00—Substation equipment, e.g. for use by subscribers
- H04M1/02—Constructional features of telephone sets
- H04M1/19—Arrangements of transmitters, receivers, or complete sets to prevent eavesdropping, to attenuate local noise or to prevent undesired transmission; Mouthpieces or receivers specially adapted therefor
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R5/00—Stereophonic arrangements
- H04R5/027—Spatial or constructional arrangements of microphones, e.g. in dummy heads
Landscapes
- Engineering & Computer Science (AREA)
- Signal Processing (AREA)
- Physics & Mathematics (AREA)
- Acoustics & Sound (AREA)
- Health & Medical Sciences (AREA)
- General Health & Medical Sciences (AREA)
- Otolaryngology (AREA)
- Circuit For Audible Band Transducer (AREA)
Abstract
MICROPHONE ARRANGEMENT
Abstract of the Disclosure A microphone arrangement, suitable for a telephone handset, comprises an array of microphone transducers, conveniently pressure transducers arranged at the vertices of a cube. Signal processing circuitry derives from the transducer outputs signals representing the magnitude and direction of the pressure gradient of the sound field at the array. In response to these signals, the microphone transducer outputs are weighted so as to direct the directional sensitivity lobe of the microphone towards the source of the maximum sound detected thereby.
- i -
Abstract of the Disclosure A microphone arrangement, suitable for a telephone handset, comprises an array of microphone transducers, conveniently pressure transducers arranged at the vertices of a cube. Signal processing circuitry derives from the transducer outputs signals representing the magnitude and direction of the pressure gradient of the sound field at the array. In response to these signals, the microphone transducer outputs are weighted so as to direct the directional sensitivity lobe of the microphone towards the source of the maximum sound detected thereby.
- i -
Description
I
MICROPHONE ARRANGEMENT
The invention relates to microphone arrangements, especially, but not exclusively, for telephones.
There is increasing concern that, in telephony, the replacement of analog switches by digital switches and the replacement of non-linear carbon microphones by linear microphones have resulted in a degradation in service quality. This is believed to be due to the lack of background noise suppression by the , 10 recently-adopted linear microphones. This increased noise creates listening problems not only at the far end but also at the near end, where the side tone suppression is degraded by the poor impedance matching of digital switches.
It has been proposed to use a pressure gradient type of linear microphone to improve background noise suppression because it discriminates in favor of sounds originating close by. In particular its response is proportional to the inverse square of the distance of the source. However, such a microphone is not entirely satisfactory For d telephone handset because it is very directive. A
user would have to orient the handset carefully to avoid nulls or low sensitivity.
An object of the present invention is to mitigate this problem.
According to the present invention there is provided a telephone microphone comprising:-(i) an array of microphone transducers;
(ii) signal generating means responsive to the I*
:
I
respective outputs of said transducers for generating a signal representing the magnitude and direction of the pressure gradient of the sound field a-t the array; and (iii) weighting means responsive to said signal for weighting the outputs of said microphone transducers to adjust the orientation of the directional lobe or axis of maximum sensitivity of the microphone towards the direction of the maximum sound detected thereby.
The microphone may also comprise means responsive to the signal generating means for deriving the direction of the pressure gradient vector.
An embodiment of the invention will now be described by way o-F example only and with reference to the accompanying drawings, in which:-Figure 1 is a schematic representation of a part of a telephone handset and its associated circuitry;
Figure 2 illustrates a sectional end view of the mouthpiece; and Figure 3 is a more detailed circuit diagram of a direction estimator shown in Figure 1.
In Figures 1 and Z, the mouthpiece part of a telephone handset is shown at 10. Four sealer pressure microphones 12, I 16 and 18 are mounted inside the mouthpiece. The microphones 12, 14, 16 and 18 are arranged in a cube, each at a corresponding one of the cube vertices. Microphone 12 is in the base of the mouthpiece 10 and thus further away from the voice source than the plane through the other three microphones.
I
The outputs of microphones 14, 16 and 18 are applied to subtracters 20, 22 and 24, respectively (Figure 1), The output of microphone 12 is also applied to the subtracters 20, 22 and 24, where it is subtracted from the outputs of the other three microphones 14, 16 and 18. The outputs of the subtracters 20, 22 and 24 thus represent three orthogonal vectors x, y, z which completely describe the sound field gradient at the array. The outputs x, y, z from the subtracters 20, 22 and 24 are applied to equalizers 26, 28, 30, respectively, and equalized because the gradient microphone response is proportional to frequency and also to define the speech channel bandwidth.
The three signals From equalizers 26, 28 and 30 are applied to multipliers 38, 40 and 42 and also to direction estimator 44. In direction estimator 44 the magnitude of the pressure gradient is derived by taking the square root of the sum of the squares of the three constituent vectors x, y, z. The direction of the pressure gradient vector is then estimated using three-dimensional trigonometry. This is normally defined in terms of three direction cosines. Assuming that the telephone user's voice is the dominant part of the field, the direction cosines, averaged over a short time, for example 200 milliseconds, will relate to the location of that voice.
The outputs of the direction estimator 44 are applied to multipliers 38, 40 and 42 and multiplied by the corresponding ones of the constituent vectors x, y, z, effectively weighting them. The products at the outputs of the multipliers 38, 40 and 42 are then summed by summer 46 to give an output which simulates a single I
pressure gradient microphone pointing directly at the voice source.
The direction estimator is shown in more detail in Figure 3. The signals x, y, z are each rectified by a corresponding one of three full wave rectifiers 50, 52 and 54, following which they are filtered by low pass filters 56~ 58 and 60, respectively. The resulting signals x, y and z, which are all positive, are combined in magnitude estimation means 62 to give r = . Dividers 64, 66 and 68, connected to the outputs of the low pass filters 56, 58, 60, respectively, and the magnitude estimation means 62, then compute the magnitudes of the direction cosines 1, m, n as follows:-= _; m = Y; n a Or r r The signs of the direction cosines m and n with respect to 1 are derived using zero-crossing comparators 70, 72 and 74 to which are applied signal x, y and z, respectively. The output of zero-crossing comparator 70, to which is applied signal x, is applied to one input of each of a pair of exclusive -OR gates 76 and 78. The other inputs of gates 76 and 78 are connected to the outputs of zero-crossing comparators 72 and 74, respectively. The outputs of gates 76 and 78 are applied to low pass filters 80 and 829 respectively, which average over about 200 milliseconds so that rapid changes of states cannot occur. the outputs of low pass filters 80 and 82 are then applied to further comparators 84 and 86, the sign outputs of which are applied to multipliers 88 and 90, respectively.
These comparators, 84 and I compare against the mean of the maximum and minimum logic levels of the exclusive -OR gates.
Multipliers 88 and 90 multiply the magnitudes of direction cosines m and n by their signs to give the direction cosines m and n.
As mentioned previously, the original signals x, y and z are multiplied by the associated direction cosines l, m and n to give weighted signals X, Y and respectively. The three weighted signals are then summed to produce the final outputs.
Embodiments of the invention not only provide discrimination against distant sources but also against sources located on or near to the plane at right angles to the voice source direction. At the same time, they provide complete flexibility to the user regarding handset orientation, and maintain the high-fidelity of reproduction characteristic of the modern linear microphone.
Although the specific implementation described herein before uses pressure microphone transducers, the invention also comprehends the use of pressure gradient microphone transducers with suitable modification of the processing circuitry. Since pressure gradient microphone transducers are directional they would conveniently be mounted with their respective axes of sensitivity aligned with the edges of the cube. However, relative orientations other than mutually perpendicular are also viable.
Likewise, although the use of an orthogonal array and corresponding orthogonal vectors simplifies processing, the array could be non-orthogonal and the processing circuitry adapted either to produce an orthogonal set of vectors for weighting or to weight the non-orthogonal vectors themselves.
Signal processing or the microphone when the three transducers are non-orthogonal (but non-coplanar also) is adapted to . .
~3~6~
provide the signal set representing orthogonal vectors ''Ojll by linear combinations of the original transducer signals So, So and Al Coy ~11 So + Coy ~12 So + Coy ~13 So
MICROPHONE ARRANGEMENT
The invention relates to microphone arrangements, especially, but not exclusively, for telephones.
There is increasing concern that, in telephony, the replacement of analog switches by digital switches and the replacement of non-linear carbon microphones by linear microphones have resulted in a degradation in service quality. This is believed to be due to the lack of background noise suppression by the , 10 recently-adopted linear microphones. This increased noise creates listening problems not only at the far end but also at the near end, where the side tone suppression is degraded by the poor impedance matching of digital switches.
It has been proposed to use a pressure gradient type of linear microphone to improve background noise suppression because it discriminates in favor of sounds originating close by. In particular its response is proportional to the inverse square of the distance of the source. However, such a microphone is not entirely satisfactory For d telephone handset because it is very directive. A
user would have to orient the handset carefully to avoid nulls or low sensitivity.
An object of the present invention is to mitigate this problem.
According to the present invention there is provided a telephone microphone comprising:-(i) an array of microphone transducers;
(ii) signal generating means responsive to the I*
:
I
respective outputs of said transducers for generating a signal representing the magnitude and direction of the pressure gradient of the sound field a-t the array; and (iii) weighting means responsive to said signal for weighting the outputs of said microphone transducers to adjust the orientation of the directional lobe or axis of maximum sensitivity of the microphone towards the direction of the maximum sound detected thereby.
The microphone may also comprise means responsive to the signal generating means for deriving the direction of the pressure gradient vector.
An embodiment of the invention will now be described by way o-F example only and with reference to the accompanying drawings, in which:-Figure 1 is a schematic representation of a part of a telephone handset and its associated circuitry;
Figure 2 illustrates a sectional end view of the mouthpiece; and Figure 3 is a more detailed circuit diagram of a direction estimator shown in Figure 1.
In Figures 1 and Z, the mouthpiece part of a telephone handset is shown at 10. Four sealer pressure microphones 12, I 16 and 18 are mounted inside the mouthpiece. The microphones 12, 14, 16 and 18 are arranged in a cube, each at a corresponding one of the cube vertices. Microphone 12 is in the base of the mouthpiece 10 and thus further away from the voice source than the plane through the other three microphones.
I
The outputs of microphones 14, 16 and 18 are applied to subtracters 20, 22 and 24, respectively (Figure 1), The output of microphone 12 is also applied to the subtracters 20, 22 and 24, where it is subtracted from the outputs of the other three microphones 14, 16 and 18. The outputs of the subtracters 20, 22 and 24 thus represent three orthogonal vectors x, y, z which completely describe the sound field gradient at the array. The outputs x, y, z from the subtracters 20, 22 and 24 are applied to equalizers 26, 28, 30, respectively, and equalized because the gradient microphone response is proportional to frequency and also to define the speech channel bandwidth.
The three signals From equalizers 26, 28 and 30 are applied to multipliers 38, 40 and 42 and also to direction estimator 44. In direction estimator 44 the magnitude of the pressure gradient is derived by taking the square root of the sum of the squares of the three constituent vectors x, y, z. The direction of the pressure gradient vector is then estimated using three-dimensional trigonometry. This is normally defined in terms of three direction cosines. Assuming that the telephone user's voice is the dominant part of the field, the direction cosines, averaged over a short time, for example 200 milliseconds, will relate to the location of that voice.
The outputs of the direction estimator 44 are applied to multipliers 38, 40 and 42 and multiplied by the corresponding ones of the constituent vectors x, y, z, effectively weighting them. The products at the outputs of the multipliers 38, 40 and 42 are then summed by summer 46 to give an output which simulates a single I
pressure gradient microphone pointing directly at the voice source.
The direction estimator is shown in more detail in Figure 3. The signals x, y, z are each rectified by a corresponding one of three full wave rectifiers 50, 52 and 54, following which they are filtered by low pass filters 56~ 58 and 60, respectively. The resulting signals x, y and z, which are all positive, are combined in magnitude estimation means 62 to give r = . Dividers 64, 66 and 68, connected to the outputs of the low pass filters 56, 58, 60, respectively, and the magnitude estimation means 62, then compute the magnitudes of the direction cosines 1, m, n as follows:-= _; m = Y; n a Or r r The signs of the direction cosines m and n with respect to 1 are derived using zero-crossing comparators 70, 72 and 74 to which are applied signal x, y and z, respectively. The output of zero-crossing comparator 70, to which is applied signal x, is applied to one input of each of a pair of exclusive -OR gates 76 and 78. The other inputs of gates 76 and 78 are connected to the outputs of zero-crossing comparators 72 and 74, respectively. The outputs of gates 76 and 78 are applied to low pass filters 80 and 829 respectively, which average over about 200 milliseconds so that rapid changes of states cannot occur. the outputs of low pass filters 80 and 82 are then applied to further comparators 84 and 86, the sign outputs of which are applied to multipliers 88 and 90, respectively.
These comparators, 84 and I compare against the mean of the maximum and minimum logic levels of the exclusive -OR gates.
Multipliers 88 and 90 multiply the magnitudes of direction cosines m and n by their signs to give the direction cosines m and n.
As mentioned previously, the original signals x, y and z are multiplied by the associated direction cosines l, m and n to give weighted signals X, Y and respectively. The three weighted signals are then summed to produce the final outputs.
Embodiments of the invention not only provide discrimination against distant sources but also against sources located on or near to the plane at right angles to the voice source direction. At the same time, they provide complete flexibility to the user regarding handset orientation, and maintain the high-fidelity of reproduction characteristic of the modern linear microphone.
Although the specific implementation described herein before uses pressure microphone transducers, the invention also comprehends the use of pressure gradient microphone transducers with suitable modification of the processing circuitry. Since pressure gradient microphone transducers are directional they would conveniently be mounted with their respective axes of sensitivity aligned with the edges of the cube. However, relative orientations other than mutually perpendicular are also viable.
Likewise, although the use of an orthogonal array and corresponding orthogonal vectors simplifies processing, the array could be non-orthogonal and the processing circuitry adapted either to produce an orthogonal set of vectors for weighting or to weight the non-orthogonal vectors themselves.
Signal processing or the microphone when the three transducers are non-orthogonal (but non-coplanar also) is adapted to . .
~3~6~
provide the signal set representing orthogonal vectors ''Ojll by linear combinations of the original transducer signals So, So and Al Coy ~11 So + Coy ~12 So + Coy ~13 So
2= Coy ~21 So + Coy ~22 So + Coy 23 So 03= Coy ~31 So + Coy ~32 So + Coy ~33 So or, in shorthand, Ox = Jo Coy Jo So.
Here,~jj is the angle between orthogonal axis "i" and non-orthogonal axis "j". Where the orthogonal signal Ox is associated with axis "i" and the non-orthogonal axis "j" is associated with the signal So.
It should be noted that, in the described embodiment, where the signal sensors are set in orthogonal axes, the diagonal elements of the above become unity (i.e. Coy ~11 = Coy ~22 = Coy = 1) whilst all other terms become zero.
Although described with respect to telephone handset microphones, the invention could advantageously be applied to general purpose microphones, particularly for use in noisy environments, such 20 do outside broadcasts.
I'D' ~,~. . ..
, }
Here,~jj is the angle between orthogonal axis "i" and non-orthogonal axis "j". Where the orthogonal signal Ox is associated with axis "i" and the non-orthogonal axis "j" is associated with the signal So.
It should be noted that, in the described embodiment, where the signal sensors are set in orthogonal axes, the diagonal elements of the above become unity (i.e. Coy ~11 = Coy ~22 = Coy = 1) whilst all other terms become zero.
Although described with respect to telephone handset microphones, the invention could advantageously be applied to general purpose microphones, particularly for use in noisy environments, such 20 do outside broadcasts.
I'D' ~,~. . ..
, }
Claims (27)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A microphone arrangement comprising:-an array of microphone transducers;
means for deriving from the outputs of said microphone transducers a signal representing the magnitude and direction of a pressure gradient of a sound field at the array;
means responsive to said signal for weighting said outputs individually such that an axis of maximum sensitivity of the microphone is directed towards a source of maximum sound detected thereby.
means for deriving from the outputs of said microphone transducers a signal representing the magnitude and direction of a pressure gradient of a sound field at the array;
means responsive to said signal for weighting said outputs individually such that an axis of maximum sensitivity of the microphone is directed towards a source of maximum sound detected thereby.
2. A microphone arrangement as defined in claim 1, wherein said arrangement comprises three pressure gradient microphone transducers arranged such that their respective axes of maximum sensitivity are not coplanar.
3. A microphone arrangement as defined in claim 1, wherein said arrangement comprises four pressure microphone transducers arranged mutually spaced in a non-planar configuration, three spaced apart in mutually intersecting planes, the fourth positioned at the intersection of such planes.
4. A microphone arrangement as defined in claim 1, wherein the means for deriving comprises means responsive to said outputs for deriving the direction of said pressure gradient.
5. A microphone arrangement as defined in claim 4, wherein said means for deriving said signal serves to generate a set of orthogonal vectors.
6. A microphone arrangement as defined in claim 1, 2 or 3, wherein said microphone transducers are orthogonally spaced.
7. A microphone arrangement as defined in claim 1, 2, or 3, wherein said microphone transducers are non-orthogonal relative to each other.
8. A microphone arrangement as defined in claim 1, 2, or 3, wherein said microphone transducers are non-orthogonal relative to each other, and wherein said means for deriving further comprises means for generating from the non-orthogonal outputs of the transducers said signal so as to represent a set of orthogonal vectors.
9. A microphone arrangement as defined in claim 1, 2 or 3, wherein said signal comprises a set of non-orthogonal vectors and the means or weighting is responsive thereto.
10. A pressure gradient microphone arrangement comprising three microphone transducers each having an axis of maximum sensitivity, the three axes each extending in a respective one of three mutually intersecting planes, means for deriving from respective outputs of said microphone transducers a signal representing the magnitude and direction of a pressure gradient of a sound field at the arrangement, and means for weighting each of said outputs of said microphone transducers, in response to said signal, so as to maximize the sensitivity of the microphone arrangement in a direction towards a source of maximum sound detected thereby.
11. A telephone set comprising a pressure gradient microphone arrangement comprising three microphone transducers each having an axis of maximum sensitivity, the three axes each extending in a respective one of three mutually intersecting planes, means for deriving from respective outputs of said microphone transducers a signal representing the magnitude and direction of a pressure gradient of a sound field at the arrangement, and means for weighting each of said outputs of said microphone transducers, in response to said signal, so as to maximize the sensitivity of the microphone arrangement in a direction towards a source of maximum sound detected thereby.
12. A telephone set as defined in claim 11, wherein said arrangement comprises three pressure gradient microphone transducers arranged such that their respective axes of maximum sensitivity are not coplanar.
13. A telephone set as defined in claim 11, wherein said arrangement comprises four pressure microphone transducers arranged mutually spaced in a non-planar configuration, three spaced apart in mutually intersecting planes, the fourth positioned at the intersection of such planes.
14. A telephone set as defined in claim 11, wherein said means for deriving comprises means responsive to said outputs for deriving the direction of said pressure gradient.
15. A telephone set as defined in claim 14, wherein said means for deriving said signal serves to generate a set of orthogonal vectors.
16. A telephone set as defined in claim 11, 12 or 13, wherein said array of microphone transducers are orthogonally spaced.
17. A telephone set as defined in claim 11, wherein said array of microphone transducers are non-orthogonally spaced.
18. A telephone set as defined in claim 12, wherein said array of microphone transducers are non-orthogonally spaced.
19. A telephone set as defined in claim 13. wherein said array of microphone transducers are non-orthogonally spaced.
20. A telephone set as defined in claim 17, wherein said means for deriving further comprises means for generating from the non-orthogonal outputs of said microphone transducers said signal so as to represent a set of orthogonal vectors.
21. A telephone set as defined in claim 18, wherein said means for deriving further comprises means for generating from the non-orthogonal outputs of said microphone transducers said signal so as to represent a set of orthogonal vectors.
22. A telephone set as defined in claim 19, wherein said means for deriving further comprises means for generating from the non-orthogonal outputs of said microphone transducers said signal so as to represent a set of orthogonal vectors.
23. A telephone set as defined in claim 11, 12 or 13, wherein said signal comprises a non-orthogonal set of vectors and the means for weighting is responsive thereto.
24. A telephone set as defined in claim 11, 12, or 13, comprising a handset and a base member wherein said microphone transducers are mounted in said handset.
25. A telephone set as defined in claim 14 or 15, comprising a handset and a base member wherein said microphone transducers are mounted in said handset.
26. A telephone set as defined in claim 11, 12 or 13, comprising a handset and a base member wherein said microphone transducers are mounted in said handset and wherein said means for deriving and said means responsive to said signal are mounted in said base member.
27. A telephone set as defined in claim 14 or 15, comprising a handset and a base member wherein said microphone transducers are mounted in said handset and wherein said means for deriving and said means responsive to said signal are mounted in said base member.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US06/778,954 US4752961A (en) | 1985-09-23 | 1985-09-23 | Microphone arrangement |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1236607A true CA1236607A (en) | 1988-05-10 |
Family
ID=25114874
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000491313A Expired CA1236607A (en) | 1985-09-23 | 1985-09-23 | Microphone arrangement |
Country Status (2)
| Country | Link |
|---|---|
| US (1) | US4752961A (en) |
| CA (1) | CA1236607A (en) |
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|---|---|---|---|---|
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Families Citing this family (54)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5239578A (en) * | 1990-05-15 | 1993-08-24 | Plantronics, Inc. | Noise cancelling apparatus for a telephone handset |
| CA2069356C (en) * | 1991-07-17 | 1997-05-06 | Gary Wayne Elko | Adjustable filter for differential microphones |
| JP3232608B2 (en) * | 1991-11-25 | 2001-11-26 | ソニー株式会社 | Sound collecting device, reproducing device, sound collecting method and reproducing method, and sound signal processing device |
| US5265122A (en) * | 1992-03-19 | 1993-11-23 | Motorola, Inc. | Method and apparatus for estimating signal weighting parameters in a diversity receiver |
| US5732143A (en) * | 1992-10-29 | 1998-03-24 | Andrea Electronics Corp. | Noise cancellation apparatus |
| US5673325A (en) * | 1992-10-29 | 1997-09-30 | Andrea Electronics Corporation | Noise cancellation apparatus |
| US5381473A (en) * | 1992-10-29 | 1995-01-10 | Andrea Electronics Corporation | Noise cancellation apparatus |
| US5664021A (en) * | 1993-10-05 | 1997-09-02 | Picturetel Corporation | Microphone system for teleconferencing system |
| US5581620A (en) * | 1994-04-21 | 1996-12-03 | Brown University Research Foundation | Methods and apparatus for adaptive beamforming |
| DE69526666T2 (en) * | 1994-10-31 | 2002-08-29 | Mike Godfrey | GLOBAL SOUND MICROPHONE SYSTEM |
| US5884254A (en) * | 1995-08-02 | 1999-03-16 | Sensimetrics Corporation | Method and apparatus for restricting microphone acceptance angle |
| US6222927B1 (en) * | 1996-06-19 | 2001-04-24 | The University Of Illinois | Binaural signal processing system and method |
| US6978159B2 (en) * | 1996-06-19 | 2005-12-20 | Board Of Trustees Of The University Of Illinois | Binaural signal processing using multiple acoustic sensors and digital filtering |
| US6987856B1 (en) | 1996-06-19 | 2006-01-17 | Board Of Trustees Of The University Of Illinois | Binaural signal processing techniques |
| US6041127A (en) * | 1997-04-03 | 2000-03-21 | Lucent Technologies Inc. | Steerable and variable first-order differential microphone array |
| US6173059B1 (en) | 1998-04-24 | 2001-01-09 | Gentner Communications Corporation | Teleconferencing system with visual feedback |
| JP3863306B2 (en) * | 1998-10-28 | 2006-12-27 | 富士通株式会社 | Microphone array device |
| US6363345B1 (en) | 1999-02-18 | 2002-03-26 | Andrea Electronics Corporation | System, method and apparatus for cancelling noise |
| JP2002540696A (en) * | 1999-03-19 | 2002-11-26 | シーメンス アクチエンゲゼルシヤフト | Method for receiving and processing audio signals in a noisy environment |
| US6594367B1 (en) | 1999-10-25 | 2003-07-15 | Andrea Electronics Corporation | Super directional beamforming design and implementation |
| US6865275B1 (en) | 2000-03-31 | 2005-03-08 | Phonak Ag | Method to determine the transfer characteristic of a microphone system, and microphone system |
| AU2000234142B2 (en) * | 2000-03-31 | 2005-05-19 | Phonak Ag | Method for providing the transmission characteristics of a microphone arrangement and microphone arrangement |
| WO2001087011A2 (en) | 2000-05-10 | 2001-11-15 | The Board Of Trustees Of The University Of Illinois | Interference suppression techniques |
| DE10026078C1 (en) * | 2000-05-25 | 2001-11-08 | Siemens Ag | Directional microphone set has 5 microphones with figure 8 directional characteristic arranged to provide sine and cosine signals |
| US7130705B2 (en) * | 2001-01-08 | 2006-10-31 | International Business Machines Corporation | System and method for microphone gain adjust based on speaker orientation |
| ITMI20020566A1 (en) * | 2002-03-18 | 2003-09-18 | Daniele Ramenzoni | DEVICE TO CAPTURE EVEN SMALL MOVEMENTS IN THE AIR AND IN FLUIDS SUITABLE FOR CYBERNETIC AND LABORATORY APPLICATIONS AS TRANSDUCER |
| US7512448B2 (en) | 2003-01-10 | 2009-03-31 | Phonak Ag | Electrode placement for wireless intrabody communication between components of a hearing system |
| US7945064B2 (en) * | 2003-04-09 | 2011-05-17 | Board Of Trustees Of The University Of Illinois | Intrabody communication with ultrasound |
| US7076072B2 (en) * | 2003-04-09 | 2006-07-11 | Board Of Trustees For The University Of Illinois | Systems and methods for interference-suppression with directional sensing patterns |
| CA2522896A1 (en) * | 2003-04-23 | 2004-11-04 | Rh Lyon Corp | Method and apparatus for sound transduction with minimal interference from background noise and minimal local acoustic radiation |
| KR100856246B1 (en) * | 2007-02-07 | 2008-09-03 | 삼성전자주식회사 | Apparatus And Method For Beamforming Reflective Of Character Of Actual Noise Environment |
| US20080255840A1 (en) * | 2007-04-16 | 2008-10-16 | Microsoft Corporation | Video Nametags |
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| US8330787B2 (en) | 2007-06-29 | 2012-12-11 | Microsoft Corporation | Capture device movement compensation for speaker indexing |
| US8165416B2 (en) * | 2007-06-29 | 2012-04-24 | Microsoft Corporation | Automatic gain and exposure control using region of interest detection |
| EP2321978A4 (en) | 2008-08-29 | 2013-01-23 | Dev Audio Pty Ltd | A microphone array system and method for sound acquisition |
| WO2016164760A1 (en) | 2015-04-10 | 2016-10-13 | Dolby Laboratories Licensing Corporation | Action sound capture using subsurface microphones |
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| US10367948B2 (en) | 2017-01-13 | 2019-07-30 | Shure Acquisition Holdings, Inc. | Post-mixing acoustic echo cancellation systems and methods |
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Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4316058A (en) * | 1972-05-09 | 1982-02-16 | Rca Corporation | Sound field transmission system surrounding a listener |
| US4536887A (en) * | 1982-10-18 | 1985-08-20 | Nippon Telegraph & Telephone Public Corporation | Microphone-array apparatus and method for extracting desired signal |
| JPS59171297A (en) * | 1983-03-17 | 1984-09-27 | Matsushita Electric Ind Co Ltd | Microphone system |
| US4495643A (en) * | 1983-03-31 | 1985-01-22 | Orban Associates, Inc. | Audio peak limiter using Hilbert transforms |
| JPS6090499A (en) * | 1983-10-24 | 1985-05-21 | Nippon Telegr & Teleph Corp <Ntt> | Sound collector |
-
1985
- 1985-09-23 CA CA000491313A patent/CA1236607A/en not_active Expired
- 1985-09-23 US US06/778,954 patent/US4752961A/en not_active Expired - Lifetime
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103329567A (en) * | 2010-10-28 | 2013-09-25 | 弗兰霍菲尔运输应用研究公司 | Apparatus and method for deriving a directional information and computer program product |
| US20160080867A1 (en) * | 2013-04-29 | 2016-03-17 | University Of Surrey | Microphone array for acoustic source separation |
| US9774953B2 (en) * | 2013-04-29 | 2017-09-26 | University Of Surrey | Microphone array for acoustic source separation |
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| US4752961A (en) | 1988-06-21 |
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