EP0240798A1 - Hearing aid noise suppression system - Google Patents
Hearing aid noise suppression system Download PDFInfo
- Publication number
- EP0240798A1 EP0240798A1 EP87104004A EP87104004A EP0240798A1 EP 0240798 A1 EP0240798 A1 EP 0240798A1 EP 87104004 A EP87104004 A EP 87104004A EP 87104004 A EP87104004 A EP 87104004A EP 0240798 A1 EP0240798 A1 EP 0240798A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- hearing aid
- circuit
- capacitor
- filter
- attack
- 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- Withdrawn
Links
- 230000001629 suppression Effects 0.000 title description 2
- 239000003990 capacitor Substances 0.000 claims description 32
- 230000003247 decreasing effect Effects 0.000 claims description 2
- 230000006870 function Effects 0.000 claims description 2
- 230000003321 amplification Effects 0.000 claims 3
- 238000003199 nucleic acid amplification method Methods 0.000 claims 3
- 238000007599 discharging Methods 0.000 claims 2
- 230000000694 effects Effects 0.000 abstract description 6
- 230000007423 decrease Effects 0.000 description 8
- 230000010354 integration Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 1
- 230000002045 lasting effect Effects 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 238000009877 rendering Methods 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 230000002123 temporal effect Effects 0.000 description 1
Images
Classifications
-
- 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
- H04R25/50—Customised settings for obtaining desired overall acoustical characteristics
- H04R25/502—Customised settings for obtaining desired overall acoustical characteristics using analog signal processing
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03G—CONTROL OF AMPLIFICATION
- H03G3/00—Gain control in amplifiers or frequency changers
- H03G3/20—Automatic control
- H03G3/30—Automatic control in amplifiers having semiconductor devices
- H03G3/32—Automatic control in amplifiers having semiconductor devices the control being dependent upon ambient noise level or sound level
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03G—CONTROL OF AMPLIFICATION
- H03G5/00—Tone control or bandwidth control in amplifiers
- H03G5/16—Automatic control
- H03G5/18—Automatic control in untuned amplifiers
Definitions
- the invention relates to hearing aids, and more particularly relates to hearing aids of the type which respond to changes of noise levels in the user's sound environment.
- a hearing aid improves when its frequency response changes with the ambient noise level. This can be done, for example, by monitoring the sound environment for the presence of low-frequency sounds, which are present in noisy environments. In devices of this type, the frequency response of the hearing aid is changed so that the device becomes less responsive to low-frequency sounds as those sounds become louder, and vice versa. This blocks out the noise and improves intelligibility for the user.
- One object of the invention is to provide a hearing aid which has a variable frequency response to improve intelligibility in high noise environments which is nonetheless comfortable for use.
- Another object is, in general, to improve on known devices of this type.
- the frequency response of the hearing aid is varied in accordance with the presence and absence of low-frequency sounds in the user's sonic environment. Further in accordance with the invention, the hearing aid responds more quickly to increases in noise level and much more slowly to decreases in noise level. This gives a user's auditory system time to adapt to the changed frequency response of the hearing aid while still preserving intelligibility in the presence of high noise levels.
- the hearing aid has a filter capacitor through which the signal from the microphone passes before entering the amplifier.
- the filter capacitor is shunted by a resistive path of variable resistance; this path is preferably the collector-emitter path of a transistor whose conductive state is determined by the presence of low-frequency sounds present at the microphone.
- the base of the transistor is connected to a charging capacitor which charges more quickly with increased noise levels and which discharges only much more slowly when the noise levels decrease. This gives the system the desired faster attack time (to increase intelligibility in the presence of noise) and much slower release time (to give the user's auditory system the opportunity to adapt and therefore to increase comfort) when the noise level diminishes.
- a hearing aid contains a microphone 2, a power amplifier 4, and a receiver 6 which functions as a loudspeaker. Between the microphone 2 and the power amplifier 4 is an adjustable high-pass filter 8 made up of two series-connected capacitors 10 and 12.
- the frequency response of this system is determined by the characteristics of the filter 8. As will be explained below, the impedance of this filter 8, and therefore the frequency response of the whole system, is varied by shunting across the capacitor 12 with a variable resistance determined by the presence of noise at the microphone 2. The mechanics by which such variation is accomplished will now be discussed.
- a circuit 14 is used to carry this variation out.
- an active low frequency bandpass filter 16 which identifies noise (here, low-frequency sounds from 500 Hz down to 150 Hz) at the microphone 2.
- the bandpass filter 16 in this example is made up of an operational amplifier 16A whose output and inverting input are bridged by a parallel RC network which includes capacitor 16B and resistor 16C.
- the input of the operational amplifier 16A, and therefore of the bandpass filter 16 is connected to the microphone 2 through a series circuit which includes a potentiometer 18, a capacitor 20, and a resistor 22.
- the potentiometer 18 is used to set the level of the circuit 14.
- Audio sounds within the frequency band passed by the bandpass filter 16 are then routed to the input of an operational amplifier 28 through a series RC circuit which includes a resistor 24 and capacitor 26.
- the operational amplifier 28 is connected as a conventional driver amplifier with a resistance 30 between its output and inverting intput.
- the operational amplifier 28 appropriately biases the base-emitter circuit of an NPN transistor 32, whose collector is connected to the voltage source.
- the transistor 32 is biased in such a way that it rectifies the signal at the output of the operational amplifier 28. (Rectification is necessary so as not to discharge the capacitor 36 described below).
- the circuit 14 responds to low-frequency noise at the microphone 2 by keeping the high-pass filter 8 in its highest-pass state. This is because a large quantity of noise at the microphone 2 will tend to keep the capacitor 36 charged up, rendering the transistor 34 entirely non-conductive and placing an open resistive circuit across the capacitor 12.
- the current flow through the transistor 32 decreases, the charge across the capacitor 36 decreases, the transistor 34 becomes more conductive, and the effect of the capacitor 12 becomes less and less important to the high-pass filter 8.
- the frequency response of the system is adapted to the noise in the user's environment; the system becomes less responsive to low frequencies as the low frequencies become more predominant.
- the resistance of resistor 38 is much less than the resistance of the resistor 42. This has the effect that increased noise levels at the microphone 2 cause the capacitor 36 to charge up more rapidly than it can discharge when the noise level at the microphone 2 decreases.
- the effect of this electrical characteristic is that when noise at the microphone 2 rises, the system soon becomes less responsive to noise so that intelligibility is maintained.
- the ambient noise level drops, the increased low-frequency response of the system is phased in over a much longer period of time, to permit the user's hearing system to adjust.
- This type of response is known to persons skilled in the art as a faster attack time and a much slower release time.
- the attack time is approximately ten times as long as the release time. It should be noted that the attack time, while fast in comparison to the release time, is not fast in the absolute sense. This is so that the hearing aid does not respond to short, momentary noise lasting less than perhaps 50 ms.
- Fig. 2 The response of the bandpass filter 16 in this example is illustrated in Fig. 2. This indicates that "noise” is defined as sounds having frequencies in the band between 500 Hz and 150 Hz. While this particular response is desired, it is not necessary for the practice of the invention and the width, shape and actual location of the band which is passed by the bandpass filter 16 can be changed.
- Fig. 3 illustrates the response of the invention to changes in the amount of 250 Hz noise at the input of the circuit 14.
- the quantity of noise is abruptly reduced. This shows that the gain of the system is cut down but then slowly rises once again until the high-pass filter 8 has reached its least high-pass state.
- the attack time constant of approximately 70 msec gives the circuit the same loundness integration behavior as the human auditory system.
- the ear has a temporal integration time constant in the range of 50 to 100 msec.
- Fig. 4 shows the overall response of the invention to a 250 Hz signal. This indicates that the response of the system begins to drop at approximately 40db below lV and only begins rising at about 47db. This curve can be shifted up and down by adjusting the potentiometer 18.
Landscapes
- Health & Medical Sciences (AREA)
- General Health & Medical Sciences (AREA)
- Neurosurgery (AREA)
- Otolaryngology (AREA)
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Acoustics & Sound (AREA)
- Signal Processing (AREA)
- Soundproofing, Sound Blocking, And Sound Damping (AREA)
- Control Of Amplification And Gain Control (AREA)
- Tone Control, Compression And Expansion, Limiting Amplitude (AREA)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US06/846,662 US4750207A (en) | 1986-03-31 | 1986-03-31 | Hearing aid noise suppression system |
US846662 | 1986-03-31 |
Publications (1)
Publication Number | Publication Date |
---|---|
EP0240798A1 true EP0240798A1 (en) | 1987-10-14 |
Family
ID=25298583
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP87104004A Withdrawn EP0240798A1 (en) | 1986-03-31 | 1987-03-18 | Hearing aid noise suppression system |
Country Status (5)
Country | Link |
---|---|
US (1) | US4750207A (da) |
EP (1) | EP0240798A1 (da) |
JP (1) | JPS62242500A (da) |
CA (1) | CA1273097A (da) |
DK (1) | DK150587A (da) |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2635680A1 (fr) * | 1988-08-30 | 1990-03-02 | Belone Electronics Corp | Prothese auditive |
US5170434A (en) * | 1988-08-30 | 1992-12-08 | Beltone Electronics Corporation | Hearing aid with improved noise discrimination |
AU637722B2 (en) * | 1990-10-30 | 1993-06-03 | Ascom Audiosys Ag | A method of supressing noise in hearing aids |
EP0635937A1 (en) * | 1993-07-22 | 1995-01-25 | Eastman Kodak Company | Circuit for controlling the overall upper cutoff frequency of an amplifier stage |
EP0746959A1 (en) * | 1993-09-20 | 1996-12-11 | Noise Cancellation Technologies, Inc. | Digitally controlled analog cancellation system |
Families Citing this family (32)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE3834316C1 (en) * | 1988-10-08 | 1989-10-26 | Eurion Ag, Rapperswil, Ch | Hearing aid |
US5235637A (en) * | 1989-01-26 | 1993-08-10 | Plantronics, Inc. | Voice communication link interface |
US5303306A (en) * | 1989-06-06 | 1994-04-12 | Audioscience, Inc. | Hearing aid with programmable remote and method of deriving settings for configuring the hearing aid |
EP0419127A3 (en) * | 1989-09-20 | 1991-10-09 | Gennum Corporation | Noise suppression system |
US5131046A (en) * | 1989-11-03 | 1992-07-14 | Etymotic Research Inc. | High fidelity hearing aid amplifier |
NO169689C (no) * | 1989-11-30 | 1992-07-22 | Nha As | Programmerbart hybrid hoereapparat med digital signalbehandling samt fremgangsmaate ved deteksjon og signalbehandlingi samme. |
US5550925A (en) * | 1991-01-07 | 1996-08-27 | Canon Kabushiki Kaisha | Sound processing device |
US5285502A (en) * | 1992-03-31 | 1994-02-08 | Auditory System Technologies, Inc. | Aid to hearing speech in a noisy environment |
US5406633A (en) * | 1992-11-03 | 1995-04-11 | Auditory System Technologies, Inc. | Hearing aid with permanently adjusted frequency response |
US6072885A (en) * | 1994-07-08 | 2000-06-06 | Sonic Innovations, Inc. | Hearing aid device incorporating signal processing techniques |
US8085959B2 (en) * | 1994-07-08 | 2011-12-27 | Brigham Young University | Hearing compensation system incorporating signal processing techniques |
US5550923A (en) * | 1994-09-02 | 1996-08-27 | Minnesota Mining And Manufacturing Company | Directional ear device with adaptive bandwidth and gain control |
US5825898A (en) * | 1996-06-27 | 1998-10-20 | Lamar Signal Processing Ltd. | System and method for adaptive interference cancelling |
FR2756086A1 (fr) * | 1996-11-19 | 1998-05-22 | Philips Electronics Nv | Appareil de signalisation routiere comprenant des organes eclairants situes au sol |
US6359992B1 (en) * | 1997-02-06 | 2002-03-19 | Micro Ear Technology | Acoustics conditioner |
US6178248B1 (en) | 1997-04-14 | 2001-01-23 | Andrea Electronics Corporation | Dual-processing interference cancelling system and method |
US6363345B1 (en) | 1999-02-18 | 2002-03-26 | Andrea Electronics Corporation | System, method and apparatus for cancelling noise |
US6408318B1 (en) | 1999-04-05 | 2002-06-18 | Xiaoling Fang | Multiple stage decimation filter |
US6594367B1 (en) | 1999-10-25 | 2003-07-15 | Andrea Electronics Corporation | Super directional beamforming design and implementation |
US6937738B2 (en) * | 2001-04-12 | 2005-08-30 | Gennum Corporation | Digital hearing aid system |
US6633202B2 (en) | 2001-04-12 | 2003-10-14 | Gennum Corporation | Precision low jitter oscillator circuit |
DE60223869D1 (de) * | 2001-04-18 | 2008-01-17 | Gennum Corp | Digitaler Quasi-Mittelwertdetektor |
EP1251715B2 (en) * | 2001-04-18 | 2010-12-01 | Sound Design Technologies Ltd. | Multi-channel hearing instrument with inter-channel communication |
US20020191800A1 (en) * | 2001-04-19 | 2002-12-19 | Armstrong Stephen W. | In-situ transducer modeling in a digital hearing instrument |
US7274794B1 (en) | 2001-08-10 | 2007-09-25 | Sonic Innovations, Inc. | Sound processing system including forward filter that exhibits arbitrary directivity and gradient response in single wave sound environment |
US7113589B2 (en) * | 2001-08-15 | 2006-09-26 | Gennum Corporation | Low-power reconfigurable hearing instrument |
KR20030096847A (ko) * | 2002-06-18 | 2003-12-31 | 세기스타 주식회사 | 포켓형 보청기 회로 |
US7171010B2 (en) * | 2003-09-11 | 2007-01-30 | Boston Acoustics, Inc. | Dynamic bass boost apparatus and method |
US7529378B2 (en) * | 2004-11-12 | 2009-05-05 | Phonak Ag | Filter for interfering signals in hearing devices |
US20060140416A1 (en) * | 2004-12-23 | 2006-06-29 | Phonak Ag | Active hearing protection system and method |
JP5688547B2 (ja) * | 2010-11-22 | 2015-03-25 | パナソニックIpマネジメント株式会社 | 音声処理装置、収音装置及び撮像装置 |
US8693716B1 (en) | 2012-11-30 | 2014-04-08 | Gn Resound A/S | Hearing device with analog filtering and associated method |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3927279A (en) * | 1972-10-16 | 1975-12-16 | Rion Co | Hearing aid |
DE3139088A1 (de) * | 1981-10-01 | 1983-04-14 | Robert Bosch Gmbh, 7000 Stuttgart | "hoergeraet" |
DE3237988A1 (de) * | 1981-10-13 | 1983-05-19 | Rion K.K., Kokubunji, Tokyo | Hoergeraet |
US4506381A (en) * | 1981-12-29 | 1985-03-19 | Mitsubishi Denki Kabushiki Kaisha | Aural transmitter device |
Family Cites Families (14)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3611145A (en) * | 1968-08-05 | 1971-10-05 | Lummus Co | Method and apparatus for the suppression of noise in process control systems |
US3678416A (en) * | 1971-07-26 | 1972-07-18 | Richard S Burwen | Dynamic noise filter having means for varying cutoff point |
AT324460B (de) * | 1973-11-21 | 1975-09-10 | Viennatome Hoergerate Produkti | Hörgerateschaltung |
US4061875A (en) * | 1977-02-22 | 1977-12-06 | Stephen Freifeld | Audio processor for use in high noise environments |
JPS5527742A (en) * | 1978-08-18 | 1980-02-28 | Seiko Epson Corp | Hearing aid |
SU723791A1 (ru) * | 1978-10-02 | 1980-03-25 | Предприятие П/Я Р-6143 | Устройство дл звукоусилени |
JPS56122243A (en) * | 1980-02-29 | 1981-09-25 | Victor Co Of Japan Ltd | Noise reduction system |
US4419544A (en) * | 1982-04-26 | 1983-12-06 | Adelman Roger A | Signal processing apparatus |
US4405831A (en) * | 1980-12-22 | 1983-09-20 | The Regents Of The University Of California | Apparatus for selective noise suppression for hearing aids |
SE428167B (sv) * | 1981-04-16 | 1983-06-06 | Mangold Stephan | Programmerbar signalbehandlingsanordning, huvudsakligen avsedd for personer med nedsatt horsel |
AU559786B2 (en) * | 1981-10-20 | 1987-03-19 | Craigwell Industries Ltd. | Hearing aid |
JPS598500A (ja) * | 1982-07-06 | 1984-01-17 | Minolta Camera Co Ltd | 補聴器 |
CA1214112A (en) * | 1983-10-12 | 1986-11-18 | William A. Cole | Noise reduction system |
US4630302A (en) * | 1985-08-02 | 1986-12-16 | Acousis Company | Hearing aid method and apparatus |
-
1986
- 1986-03-31 US US06/846,662 patent/US4750207A/en not_active Expired - Lifetime
-
1987
- 1987-03-18 EP EP87104004A patent/EP0240798A1/en not_active Withdrawn
- 1987-03-25 DK DK150587A patent/DK150587A/da not_active IP Right Cessation
- 1987-03-25 JP JP62072959A patent/JPS62242500A/ja active Pending
- 1987-03-27 CA CA000533200A patent/CA1273097A/en not_active Expired - Fee Related
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3927279A (en) * | 1972-10-16 | 1975-12-16 | Rion Co | Hearing aid |
DE3139088A1 (de) * | 1981-10-01 | 1983-04-14 | Robert Bosch Gmbh, 7000 Stuttgart | "hoergeraet" |
DE3237988A1 (de) * | 1981-10-13 | 1983-05-19 | Rion K.K., Kokubunji, Tokyo | Hoergeraet |
US4506381A (en) * | 1981-12-29 | 1985-03-19 | Mitsubishi Denki Kabushiki Kaisha | Aural transmitter device |
Non-Patent Citations (3)
Title |
---|
HEARING INSTRUMENTS, vol. 37, no. 2, February 1986, pages 19-20,22, Cleveland, US; J.M. KATES: "Signal processing for hearing aids" * |
PATENT ABSTRACTS OF JAPAN, vol. 4, no. 56 (E-8)[538], 25th April 1980; & JP-A-55 27 742 (SUWA SEIKOSHA K.K.) 28-02-1980 * |
PATENT ABSTRACTS OF JAPAN, vol. 8, no. 88 (E-240)[125], 21st April 1984; & JP-A-59 008 500 (MINOLTA CAMERA K.K.) 17-01-1984 * |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2635680A1 (fr) * | 1988-08-30 | 1990-03-02 | Belone Electronics Corp | Prothese auditive |
US5170434A (en) * | 1988-08-30 | 1992-12-08 | Beltone Electronics Corporation | Hearing aid with improved noise discrimination |
AU637722B2 (en) * | 1990-10-30 | 1993-06-03 | Ascom Audiosys Ag | A method of supressing noise in hearing aids |
EP0635937A1 (en) * | 1993-07-22 | 1995-01-25 | Eastman Kodak Company | Circuit for controlling the overall upper cutoff frequency of an amplifier stage |
EP0746959A1 (en) * | 1993-09-20 | 1996-12-11 | Noise Cancellation Technologies, Inc. | Digitally controlled analog cancellation system |
EP0746959A4 (en) * | 1993-09-20 | 2001-10-17 | Noise Cancellation Tech | DIGITAL CONTROL ANALOGUE CANCELLATION SYSTEM |
Also Published As
Publication number | Publication date |
---|---|
JPS62242500A (ja) | 1987-10-23 |
CA1273097A (en) | 1990-08-21 |
DK150587A (da) | 1987-10-01 |
DK150587D0 (da) | 1987-03-25 |
US4750207A (en) | 1988-06-07 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): AT CH DE FR GB IT LI NL |
|
17P | Request for examination filed |
Effective date: 19871106 |
|
17Q | First examination report despatched |
Effective date: 19900129 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION HAS BEEN WITHDRAWN |
|
18W | Application withdrawn |
Withdrawal date: 19910204 |
|
R18W | Application withdrawn (corrected) |
Effective date: 19910204 |
|
RIN1 | Information on inventor provided before grant (corrected) |
Inventor name: GOKHIN, YURI Inventor name: GEBERT, ANTON M. |