EP1653768A2 - Procédé pour réduire la puissance perturbatrice dans un microphone directionnel et système électro-acoustique correspondant - Google Patents

Procédé pour réduire la puissance perturbatrice dans un microphone directionnel et système électro-acoustique correspondant Download PDF

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Publication number
EP1653768A2
EP1653768A2 EP05109462A EP05109462A EP1653768A2 EP 1653768 A2 EP1653768 A2 EP 1653768A2 EP 05109462 A EP05109462 A EP 05109462A EP 05109462 A EP05109462 A EP 05109462A EP 1653768 A2 EP1653768 A2 EP 1653768A2
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EP
European Patent Office
Prior art keywords
microphone
power
signal
directional microphone
directional
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.)
Withdrawn
Application number
EP05109462A
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German (de)
English (en)
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EP1653768A3 (fr
Inventor
Eghart Fischer
Henning Puder
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sivantos GmbH
Original Assignee
Siemens Audioligische Technik GmbH
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Publication date
Application filed by Siemens Audioligische Technik GmbH filed Critical Siemens Audioligische Technik GmbH
Publication of EP1653768A2 publication Critical patent/EP1653768A2/fr
Publication of EP1653768A3 publication Critical patent/EP1653768A3/fr
Withdrawn legal-status Critical Current

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R25/00—Deaf-aid sets, i.e. electro-acoustic or electro-mechanical hearing aids; Electric tinnitus maskers providing an auditory perception
    • H04R25/40—Arrangements for obtaining a desired directivity characteristic
    • H04R25/407—Circuits for combining signals of a plurality of transducers
    • 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

Definitions

  • the present invention relates to a method for reducing interference power in a directional microphone by providing at least two microphone signals and adaptive filtering of the at least two microphone signals to obtain a directivity, wherein at least one adaptation parameter can be optimized. Moreover, the present invention relates to a corresponding acoustic system with directional microphone.
  • Disturbances are defined on the one hand as the signals coming from undesired directions, in this case outside a certain angular range around the 0 ° direction, e.g. +/- 60 °, and on the other hand as microphone noise, which can be amplified when forming the directivity, especially in low-frequency ranges.
  • microphone noise increases when the directivity of a directional microphone is increased.
  • a method is also available for generating an omni-characteristic with low microphone noise by parameter selection. A suppression of interference is not provided here.
  • a disadvantage of the known solutions is thus that no uniform approach for the simultaneous optimization of the total power of microphone noise and signal sources that come from undesirable directions is available.
  • the object of the present invention is thus to propose a method for the reduction of interference power in a directional microphone, in which both the microphone noise and the signal powers of interference sources are taken into account.
  • a corresponding acoustic system should be specified.
  • this object is achieved according to claim 1 by a method for reducing interference power in a directional microphone by providing at least two microphone signals and adaptive filtering of the at least two microphone signals to achieve a directional effect, wherein at least one adaptation parameter can be optimized, and adjusting the directivity by changing the at least one adaptation parameter such that the sum of interference power is reduced.
  • the interference power is composed of microphone noise and the power of unwanted signal sources. Thus, noise and noise sources can be considered equally.
  • the directional microphone is in a given direction, in particular in the 0 ° direction and signal sources are considered undesirable if they are outside a specified angle around the given direction. By adjusting the adaptive filters, angular ranges can thus be defined in which sound sources are treated as sources of interference.
  • the at least one adaptation parameter of the filter device is modified such that the total output signal power is minimized, but the signal from the predetermined or 0 ° direction is not changed. With the reduction of the output signal power, the noise power is automatically reduced as a whole, and yet the gain in the main incident direction remains unaffected.
  • the invention provides a corresponding acoustic system according to claim 4.
  • the invention guarantees an uninfluenced signal from the 0 ° direction in combination with an adaptation method which causes a minimization of the sum of the interfering signals.
  • the filters of the filter device are preferably first-order or second-order adaptive finite impulse response (FIR) filters.
  • FIR finite impulse response
  • the reduction of interference power takes place in several subbands.
  • the reduction of interference power in different frequency ranges can take place selectively.
  • Two microphones M1 and M2 receive a time-dependent sound signal s (t).
  • a microphone noise signal n1 (t) or n2 (t) mixes with the ideal microphone signals.
  • the respective sum signals are digitized with an analog-to-digital converter so that the microphone signals x 1 (k) and x 2 (k) result.
  • a first-order differential microphone subtracts the two microphone signals x 1 (k) and x 2 (k) crosswise, as is known for directional microphones.
  • the signals are delayed in the corresponding paths with timers T and a difference signal is multiplied by an adaptation parameter a.
  • the equalization provides a mono output signal y (k).
  • the differential microphone DM1 can be realized by two FIR filters FIR1 and FIR2 with the transfer functions 1 + az -1 and -az -1 . This is shown schematically in FIG.
  • the filter coefficients can not be chosen freely, but depend on the parameter a. This dependence, which results from the conversion of the filters from the differential microphone DM1, ensures that the output signal after directional microphone processing contains the signal from the 0 ° direction (useful signal direction) unchanged, regardless of the choice of the parameter a. To optimize parameter a, it must be adapted to the respective acoustic situation.
  • the microphone noise also increases with increasing a.
  • the aim now is to keep the total interference power of a directional microphone as low as possible. Therefore, on the one hand to adjust the directivity of the directional microphone so that the sound of a source of interference is suppressed as much as possible and on the other hand, the microphone noise is as low as possible.
  • the power of the interference signal ST and the microphone noise are qualitatively plotted over the parameter a.
  • a sum signal SUM from the two signals ST and MR represents the total interference power for the directional microphone. The goal is to find the minimum of this curve and the corresponding Use parameter value a min for the adaptive filter.
  • the adaptation of the directional microphone to a specific interference source or the optimization of the parameter a can be carried out, for example, by a gradient method comparable to the LMS method (least mean squares). But there are also other embodiments conceivable. With the gradient method, the adaptation condition is very simple. It can simply be noted as a minimization of the average output power of the directional microphone.
  • the interference consists of two components: microphone noise and interference from signal sources that are incident from undesired directions.
  • An attenuation of direction-dependent signal sources can be achieved by selecting the parameter a> 0.
  • the adaptive method is also allowed to select the parameters smaller than 0, the directivity is reduced, but also the power of the microphone noise is reduced.
  • the method that measures the sum of the noise powers, i. of microphone noise and signal sources from undesired directions, in each frequency band is minimized.
  • the parameter a can be found by finding the minimum of the mean square error. This means that the expected value of the output signal should be minimal, ie e ⁇
  • 2 ⁇ ! min
  • a directional microphone of the second order has according to FIG. 6 in addition to the microphones M1 and M2 via a third microphone M3. Also, the output signal is disturbed by noise microphone n3 (t), and digitally converted the corresponding sum signal to a microphone output signal x 3 (k).
  • the differential microphone DM2 generates after the usual equalization EQO from the three microphone signals x 1 (k), x 2 (k) and x 3 (k) an output signal y (k). In this case, in a first stage, the microphone signals are subtracted crosswise after a corresponding time delay T and a signal weighting with the factor a takes place in two sub-branches, so that the two intermediate signals z 1 (k) and z 2 (k) result.
  • the output signal of the equalizer EQO is again denoted by y (k).
  • the differential microphone of the second order can be described analogously to the differential microphone of the first order by three FIR filters, as shown in FIG. 7 (see also FIG.
  • the first FIR filter FIR1 has the transfer function 1 + ( a + b ) z - 1 - a b z - 2
  • the second filter FIR2 has the transfer function - ( a + b ) - 2 ( a b + 1 ) z - 1 - ( a + b ) z - 2 and the third filter FIR3, the transfer function a b + ( a + b ) z - 1 + z - 2
  • the minimum of the mean square error of the output signal is to be calculated, ie e ⁇
  • 2 ⁇ ! min
  • the method has an increased robustness to mismatch of the microphones or mismatch by head influences, for example, of a hearing aid wearer or headset wearer.
  • the adaptive method will select the parameters to reduce the overall disturbance again.
  • the choice of parameters which can achieve spatial attenuation without mismatching is then automatically prevented in favor of reducing microphone noise. The reason is, that the spatial attenuation due to the mismatch anyway can not be formed.
  • mismatching could result in spatial attenuation (attenuation in one or more spatial directions), but in addition to this microphone noise is amplified.

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  • Health & Medical Sciences (AREA)
  • General Health & Medical Sciences (AREA)
  • Otolaryngology (AREA)
  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Neurosurgery (AREA)
  • Circuit For Audible Band Transducer (AREA)
EP05109462A 2004-11-02 2005-10-12 Procédé pour réduire la puissance perturbatrice dans un microphone directionnel et système électro-acoustique correspondant Withdrawn EP1653768A3 (fr)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE102004052912A DE102004052912A1 (de) 2004-11-02 2004-11-02 Verfahren zur Reduktion von Störleistungen bei einem Richtmikrophon und entsprechendes Akustiksystem

Publications (2)

Publication Number Publication Date
EP1653768A2 true EP1653768A2 (fr) 2006-05-03
EP1653768A3 EP1653768A3 (fr) 2010-06-02

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EP05109462A Withdrawn EP1653768A3 (fr) 2004-11-02 2005-10-12 Procédé pour réduire la puissance perturbatrice dans un microphone directionnel et système électro-acoustique correspondant

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US (1) US8135142B2 (fr)
EP (1) EP1653768A3 (fr)
DE (1) DE102004052912A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1945000A1 (fr) * 2007-01-11 2008-07-16 Siemens Audiologische Technik GmbH Procédé destiné à la réduction de puissances d'interférence et système acoustique correspondant
US8238593B2 (en) 2006-06-23 2012-08-07 Gn Resound A/S Hearing instrument with adaptive directional signal processing

Families Citing this family (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1994788B1 (fr) 2006-03-10 2014-05-07 MH Acoustics, LLC Reseau de microphones directionnels reducteur de bruit
DE102007010601A1 (de) 2007-03-05 2008-09-25 Siemens Audiologische Technik Gmbh Hörsystem mit verteilter Signalverarbeitung und entsprechendes Verfahren
WO2009143434A2 (fr) * 2008-05-23 2009-11-26 Analog Devices, Inc. Microphone à large gamme dynamique
DE102008055760A1 (de) 2008-11-04 2010-05-20 Siemens Medical Instruments Pte. Ltd. Adaptives Mikrofonsystem für ein Hörgerät und zugehöriges Verfahren zum Betrieb
DE102009014053B4 (de) * 2009-03-19 2012-11-22 Siemens Medical Instruments Pte. Ltd. Verfahren zum Einstellen einer Richtcharakteristik und Hörvorrichtungen
US9232310B2 (en) * 2012-10-15 2016-01-05 Nokia Technologies Oy Methods, apparatuses and computer program products for facilitating directional audio capture with multiple microphones
EP2848007B1 (fr) * 2012-10-15 2021-03-17 MH Acoustics, LLC Réduction du bruit dans un réseau de microphones directionnelle
WO2014103066A1 (fr) * 2012-12-28 2014-07-03 共栄エンジニアリング株式会社 Procédé, dispositif et programme de séparation de sources sonores
CN105051814A (zh) 2013-03-12 2015-11-11 希尔Ip有限公司 降噪方法及系统
CN116017635B (zh) * 2022-12-16 2023-09-05 广东保伦电子股份有限公司 一种用于数字u段无线话筒的频率扫描方法及服务器

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2001001731A1 (fr) 1999-06-24 2001-01-04 Widex A/S Procede de commande de la directionalite de la caracteristique de reception de son d'une aide auditive, et aide auditive dans laquelle est applique ledit procede
DE10327889B3 (de) 2003-06-20 2004-09-16 Siemens Audiologische Technik Gmbh Verfahren zum Betrieb eines Hörhilfegerätes sowie Hörhilfegerät mit einem Mikrofonsystem, bei dem unterschiedliche Richtcharakteristiken einstellbar sind und Programmiergerät dafür

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5224170A (en) * 1991-04-15 1993-06-29 Hewlett-Packard Company Time domain compensation for transducer mismatch
GB9813973D0 (en) * 1998-06-30 1998-08-26 Univ Stirling Interactive directional hearing aid
DE10024267A1 (de) * 2000-05-17 2001-11-29 Bosch Gmbh Robert Rundfunkempfänger für den Empfang von digitalen Rundfunksignalen und Verfahren zum Empfang von digitalen Rundfunksignalen
WO2001097558A2 (fr) * 2000-06-13 2001-12-20 Gn Resound Corporation Directionnalite adaptative basee sur un modele polaire fixe
CA2420989C (fr) * 2002-03-08 2006-12-05 Gennum Corporation Systeme de microphones directifs a faible bruit
US7577262B2 (en) * 2002-11-18 2009-08-18 Panasonic Corporation Microphone device and audio player

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2001001731A1 (fr) 1999-06-24 2001-01-04 Widex A/S Procede de commande de la directionalite de la caracteristique de reception de son d'une aide auditive, et aide auditive dans laquelle est applique ledit procede
DE10327889B3 (de) 2003-06-20 2004-09-16 Siemens Audiologische Technik Gmbh Verfahren zum Betrieb eines Hörhilfegerätes sowie Hörhilfegerät mit einem Mikrofonsystem, bei dem unterschiedliche Richtcharakteristiken einstellbar sind und Programmiergerät dafür

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8238593B2 (en) 2006-06-23 2012-08-07 Gn Resound A/S Hearing instrument with adaptive directional signal processing
EP1945000A1 (fr) * 2007-01-11 2008-07-16 Siemens Audiologische Technik GmbH Procédé destiné à la réduction de puissances d'interférence et système acoustique correspondant
US8090128B2 (en) 2007-01-11 2012-01-03 Siemens Audiologische Technik Gmbh Method for reducing interference powers and corresponding acoustic system

Also Published As

Publication number Publication date
DE102004052912A1 (de) 2006-05-11
EP1653768A3 (fr) 2010-06-02
US20060104459A1 (en) 2006-05-18
US8135142B2 (en) 2012-03-13

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