WO1999005840A1 - Procede et appareil de reglage automatique des gains d'un haut-parleur et d'un microphone dans un telephone mobile - Google Patents

Procede et appareil de reglage automatique des gains d'un haut-parleur et d'un microphone dans un telephone mobile Download PDF

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Publication number
WO1999005840A1
WO1999005840A1 PCT/US1997/013003 US9713003W WO9905840A1 WO 1999005840 A1 WO1999005840 A1 WO 1999005840A1 US 9713003 W US9713003 W US 9713003W WO 9905840 A1 WO9905840 A1 WO 9905840A1
Authority
WO
WIPO (PCT)
Prior art keywords
gain
microphone
background noise
speaker
noise level
Prior art date
Application number
PCT/US1997/013003
Other languages
English (en)
Inventor
Andrew P. Dejaco
Michael T. Coad
Original Assignee
Qualcomm Incorporated
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Qualcomm Incorporated filed Critical Qualcomm Incorporated
Priority to PCT/US1997/013003 priority Critical patent/WO1999005840A1/fr
Priority to AU38124/97A priority patent/AU3812497A/en
Publication of WO1999005840A1 publication Critical patent/WO1999005840A1/fr

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Classifications

    • 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
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M1/00—Substation equipment, e.g. for use by subscribers
    • H04M1/60—Substation equipment, e.g. for use by subscribers including speech amplifiers
    • H04M1/6008—Substation equipment, e.g. for use by subscribers including speech amplifiers in the transmitter circuit
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M1/00—Substation equipment, e.g. for use by subscribers
    • H04M1/60—Substation equipment, e.g. for use by subscribers including speech amplifiers
    • H04M1/6016—Substation equipment, e.g. for use by subscribers including speech amplifiers in the receiver circuit

Definitions

  • the invention generally relates to mobile telephones and in particular to the audio microphone and speaker of a mobile telephone.
  • Cellular telephones and other mobile telephones are commonly employed within a wide range of differing noise environments.
  • a cellular telephone may be employed within a relatively quiet office or home environment or within a relatively noisy manufacturing or traffic environment.
  • a user tends to speak more loudly into the microphone of the cellular telephone than in relatively quiet environments. This is a natural tendency arising from the assumption by the user that he or she must speak more loudly to be heard over the noise. Yet, such is often not necessary and, indeed, may be counterproductive.
  • the microphone of the cellular telephone may be highly directional and therefore will not detect and amplify all of the noise that the user hears. Hence, it is unnecessary for the user to speak more loudly.
  • the cellular telephone may be capable of processing only a limited dynamic range of sound levels such that the voice of the user becomes clipped if the user speaks too loudly into the microphone. Such clipping can result in a decrease in the signal to noise ratio between the transmitted voice and the transmitted background noise level. Hence, by speaking loudly into the microphone, it may actually become more difficult for the listener to distinguish the voice of the user.
  • FIG. 1 illustrates a voice signal 10 and a background noise signal 12 input to a cellular telephone.
  • the background noise level increases beginning at time 14.
  • the user speaks more loudly resulting in an increase in the input voice signal level.
  • the noise level continues to rise, the user speaks even more loudly until reaching a point 16 where clipping begins.
  • the voice is clipped yielding a lower signal to noise ratio, as well as, a possibly distorted voice signal.
  • FIG. 2 illustrates the resulting changes in the signal to noise ratio. As can be seen, the signal to noise ratio decreases following time 16.
  • a user who tries to speak more loudly can actually reduce intelligibility. Even if clipping does not occur, the user speaking more loudly may cause annoyance to the listener, perhaps resulting in a need for the listener to decrease the volume of the speaker of his or her telephone. For many telephones, particularly non-mobile telephones, the volume of the speaker cannot be adjusted and hence the listener may not be able to achieve a comfortable volume level. Moreover, privacy may be jeopardized at the listener's end, if the voice of the user is too loud and the listener cannot decrease the speaker volume level.
  • a cellular telephone, or other mobile telephone with a means for adjusting the gain of a microphone of the telephone based upon the detected noise level in which the cellular telephone in operated.
  • the gain of the microphone is automatically decreased thereby compensating for the tendency of telephone users to speak more loudly in noisy environments.
  • any clipping that might otherwise occur as a result of the user speaking more loudly is avoided and the signal to noise ratio is thereby not decreased.
  • the microphone gain decreases, the volume level of the voice of the user as it is output from the telephone of the other party to the telephone call is not unduly loud. Hence, the other party need not manually decrease the speaker gain of his or her telephone.
  • automatic microphone gain adjustment is achieved by providing the cellular telephone with a means for detecting the background noise level of the environment in which the mobile telephone is operating and a means for setting the gain of a microphone of the mobile telephone based upon the detected background noise levels.
  • the means for setting the gain of the microphone operates to decrease the gain in response to an increase in background noise by an amount inversely proportional to the background noise level.
  • the microphone gain is reduced by half the value of the increase in background noise measured in decibels.
  • the mobile telephone further includes a means for automatically setting the gain of a speaker of the mobile telephone based upon the background noise level. More specifically, the means for setting the gain of the speaker operates to increase the gain in response to an increase in the background noise level. Hence, the user need not manually increase the speaker gain if the background noise level increases.
  • the invention is particularly well suited for use in cellular telephones employing digital signal processing (DSP) units.
  • DSP digital signal processing
  • Many such cellular telephones include hardware or software within the DSP for calculating the background noise level from the input signal for the purposes of performing noise reduction.
  • An exemplary embodiment for calculating the background noise level is described in detail in U.S. Patent No. 5,414,796, entitled "Variable Rate Vocoder", which is assigned to the assignee of the present invention and incorporated by reference herein.
  • the DSP is merely reconfigured or reprogrammed to apply the detected noise level to look-up tables relating various noise levels to appropriate speaker and microphone gain levels.
  • a wide variety of other implementations are also possible.
  • FIG. 1 is a graph illustrating background noise levels and corresponding input voice levels for a cellular telephone operating in a changing noise environment
  • FIG. 2 is a graph illustrating the signal to noise level for the input voice and noise signals of FIG. 1;
  • FIG. 3 is a block diagram of a cellular telephone configured in accordance with a preferred embodiment of the invention.
  • FIG. 4 is a block diagram of a microphone gain look-up table of the cellular telephone of FIG. 3;
  • FIG. 5 is a block diagram of a speaker gain look-up table of the cellular telephone of FIG. 3.
  • FIG. 3 illustrates a cellular telephone 100 having a microphone 102, a speaker 104 and an antenna 106.
  • Pertinent internal components of the telephone illustrated in FIG. 2 include a control unit 108, a Digital Signal Processor (DSP) 110, and a receiver/transmitter unit 112. Also, included is a microphone gain control unit 113 and a speaker gain control unit 115.
  • DSP Digital Signal Processor
  • a user of cellular telephone 100 speaks into microphone 102 and his or her voice and any detected background noise are routed by control unit 108 into DSP 110 for processing therein.
  • the processed voice signals are encoded, by units not separately shown, using the cellular transmission protocol of Code Division Multiple Access (CDMA) as described in detail in the Telecommunication Industry Association's TIA/EIA/IS-95-A Mobile Station-Base Station Capability Standard for Dual-Mode Wideband Spread Spectrum Cellular System.
  • CDMA Code Division Multiple Access
  • the encoded signals are routed to receiver /transmitter 112, then transmitted via antenna 106 to a local base station (not shown.)
  • the signals may be forwarded from there to a remote telephone which may be another cellular telephone, other mobile phone or a land-line connected to a Public Switched Telephone Network (PSTN) (not shown).
  • PSTN Public Switched Telephone Network
  • Voice signals transmitted to cellular phone 100 are received via antenna 106 and receiver/transmitter 112, processed by DSP 110 and output through the speaker all under the control of the control unit 108.
  • the DSP 110 may, depending upon the implementation, perform any of a variety of conventional digital processing functions on the voice signals. Additionally, DSP 110 determines the background noise level of the local environment from the signals detected by microphone 102 and sets the gain of microphone 102 to a level selected to compensate for the natural tendency of the user of cellular telephone 100 to speak more loudly in noisy environments. In the exemplary embodiment, the microphone gain is set to a level that is generally inversely proportional to the background noise level. In the exemplary embodiment, the microphone gain is decreased by half the increase in background noise measured in decibels.
  • DSP 110 includes background noise level detection unit 114, microphone gain look-up table 116 and speaker gain look-up table 118.
  • Background noise level detector 114 determines, in accordance with conventional techniques, the background noise level from signals received from microphone 102, yielding a digital value representative of the background noise level. The digital value may, for example, represent the background noise energy in decibels.
  • DSP 110 applies the digital value to microphone gain look-up table 116 to read out a microphone gain value for applying to microphone 102 via microphone gain control unit 113.
  • the background noise level B' is determined in the current frame based on the previous frame background noise level B and the current frame energy Ef.
  • the new background noise level B' for use during the next frame two values are computed.
  • the first value Vi is simply the current frame energy E f .
  • V 2 min (160000, max (K'B, B+l) ) (2)
  • FIG. 4 illustrates an exemplary microphone gain look-up table having entries 120 for various background noise levels and entries 122 for corresponding microphone gain values.
  • the microphone gain values may, for example, be digital representations of voltage or current levels for applying to an amplifier of microphone 102 (not shown).
  • Entries 120 may specify individual noise levels or ranges of noise levels. Every expected quantized input noise level is represented within the look-up table 116. If a noise level is detected that does not have a corresponding entry in the table, a default value is employed.
  • look-up table 116 may be implemented as a portion of read only memory (ROM). In other implementations, look up table 116 may be implemented using other appropriate techniques, such as a software algorithms.
  • the background noise level value read out from microphone gain look-up table 116 is applied to microphone 102 to adjust its gain.
  • the background noise levels may be calculated and corresponding gain levels read out and applied to microphone 102 either continuously or periodically.
  • the microphone gain is readjusted every two or three seconds, thereby accommodating for the typical delay between an increase in the background noise level and a corresponding increase in the loudness of the voice of the user.
  • the noise level is detected and the gain set only once per call or perhaps only at power-up of the cellular telephone.
  • the gain of speaker 104 is automatically adjusted manner similar to the microphone gain.
  • the background noise level value calculated by background noise level detection unit 114 is applied to speaker gain look-up table 118 to read out a speaker gain value appropriate for the background noise level.
  • An exemplary speaker gain look-up table is illustrated in FIG. 5.
  • Speaker gain look-up table 118 has entries 130 for background noise levels and entries 132 for corresponding speaker gain values.
  • the speaker gain values may represent voltage or current levels for controlling the gain of an amplifier (not separately shown) of the speaker.
  • a default value may be employed for any noise levels not having an entry in speaker gain look-up table 118.
  • the speaker gain look-up table 118 may be accessed continuously or periodically, or perhaps only once per call or only at power-up.
  • speaker gain look-up table 118 is preferably programmed with values selected to increase gain with increasing noise levels.
  • the speaker gain values may, for example, be set to increase gain by an amount substantially proportional to an increase in background noise levels.
  • the user need not adjust the speaker gain by a manual control unit (not shown). Rather, automatic adjustment is performed.
  • What has been described are exemplary embodiments of a cellular telephone configured to automatically decrease microphone gain and increase speaker gain in response to an increase in background noise levels of the environment of the cellular telephone.
  • the decrease in microphone gain and the increase in speaker gain are both proportional to an increase in background noise levels.
  • any desired relationship may be employed merely by pre-programming the look-up tables with appropriate values.
  • the values may, for example, be initially calculated based upon a mathematical relationship such as simple proportionality.
  • appropriate values may be determined empirically by measuring the extent to which actual telephone user increases his or her speaking volume in response to changes in background noise levels.

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  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Telephone Function (AREA)

Abstract

L'invention porte sur un téléphone cellulaire (100) capable de régler automatiquement le gain d'un microphone (102) en fonction du niveau de bruit détecté dans l'environnement dans lequel fonctionne le téléphone cellulaire (100). Lorsque le niveau de bruit augmente, le gain du microphone (102) décroît automatiquement, ce qui compense la tendance naturelle des utilisateurs du téléphone à parler plus fort dans des environnements bruyants. De même, lors de la réduction du gain du microphone, l'écrêtage, qui pourrait se produire lorsque la voix de l'utilisateur vient saturer le circuit micro, est évité, le rapport signal/bruit n'étant par conséquent pas réduit. De plus, du fait que le gain du microphone diminue, le volume de la voix de l'utilisateur généré dans le combiné téléphonique de l'autre partie n'est pas excessivement fort. L'autre partie n'a donc pas besoin de réduire manuellement le gain du haut-parleur de son téléphone. Selon une autre réalisation, le téléphone cellulaire (100) comprend un processeur de signaux numériques (110) configuré ou programmé pour appliquer le niveau de bruit détecté aux tables de consultation (116, 118) mettant en correspondance divers niveaux de bruit et les niveaux de gain appropriés du haut-parleur et du microphone. Selon encore une autre réalisation, le téléphone mobile comprend un haut-parleur (104) dont le gain est réglé de façon à augmenter en réaction à l'augmentation du niveau de bruit de fond.
PCT/US1997/013003 1997-07-24 1997-07-24 Procede et appareil de reglage automatique des gains d'un haut-parleur et d'un microphone dans un telephone mobile WO1999005840A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
PCT/US1997/013003 WO1999005840A1 (fr) 1997-07-24 1997-07-24 Procede et appareil de reglage automatique des gains d'un haut-parleur et d'un microphone dans un telephone mobile
AU38124/97A AU3812497A (en) 1997-07-24 1997-07-24 Method and apparatus for automatically adjusting speaker and microphone gains within a mobile telephone

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/US1997/013003 WO1999005840A1 (fr) 1997-07-24 1997-07-24 Procede et appareil de reglage automatique des gains d'un haut-parleur et d'un microphone dans un telephone mobile

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Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000059110A2 (fr) * 1999-03-30 2000-10-05 Qualcomm Incorporated Procede et appareil pour le reglage automatique de gains de microphone et de haut-parleur au sein d'un telephone mobile
WO2000060833A1 (fr) * 1999-04-07 2000-10-12 Siemens Aktiengesellschaft Terminal de communication
EP1065653A2 (fr) * 1999-07-01 2001-01-03 Matsushita Electric Industrial Co., Ltd. Dispositif pour l'estimation du niveau de bruit de fond et pour le contrôle du volume d'un appareil de communication
GB2351881A (en) * 1998-03-30 2001-01-10 Nec Corp Portable terminal device for controlling received voice level and transmitted voice level
WO2001089184A1 (fr) * 2000-05-18 2001-11-22 Ericsson Inc. Gain de signal de communication pouvant etre adapte au bruit
WO2003003572A1 (fr) * 2001-06-28 2003-01-09 Danacom A/S Commande de volume dans une unite d'interface de dispositif de communication
EP1385324A1 (fr) * 2002-07-22 2004-01-28 Siemens Aktiengesellschaft Procédé et dispositif pour la réduction du bruit de fond
US6744882B1 (en) 1996-07-23 2004-06-01 Qualcomm Inc. Method and apparatus for automatically adjusting speaker and microphone gains within a mobile telephone
US6760453B1 (en) 1998-03-30 2004-07-06 Nec Corporation Portable terminal device for controlling received voice level and transmitted voice level
KR100678194B1 (ko) * 2002-10-26 2007-02-01 삼성전자주식회사 수신 음성 자동 이득 제어 방법 및 장치
KR100742140B1 (ko) * 1999-03-30 2007-07-24 퀄컴 인코포레이티드 이동전화 스피커와 마이크로폰 이득을 자동으로 조정하는방법 및 장치
EP2381738A1 (fr) * 2009-01-19 2011-10-26 Huawei Device Co., Ltd. Terminal de communication et dispositif et procédé de réglage du volume adaptatif
CN109889665A (zh) * 2019-02-26 2019-06-14 努比亚技术有限公司 一种音量调节方法、移动终端及存储介质

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EP0495360A2 (fr) * 1991-01-15 1992-07-22 AEG MOBILE COMMUNICATION GmbH Disposition pour commande de volume deans une dispositif téléphonique mains libres
EP0507482A2 (fr) * 1991-04-04 1992-10-07 Nokia Mobile Phones Ltd. Générateur de sonnerie pour appareil téléphonique avec réglage automatique du niveau sonore en function du niveau du bruit ambiant

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US3889059A (en) * 1973-03-26 1975-06-10 Northern Electric Co Loudspeaking communication terminal apparatus and method of operation
DE3426815A1 (de) * 1984-02-28 1985-08-29 Siemens AG, 1000 Berlin und 8000 München Pegelregulierung fuer eine fernsprechstation mit freisprechen
WO1987001255A1 (fr) * 1985-08-20 1987-02-26 Motorola, Inc. Haut-parleur pour telephones par radio et par lignes terrestres
US4829565A (en) * 1987-10-20 1989-05-09 Goldberg Robert M Telephone with background volume control
EP0495360A2 (fr) * 1991-01-15 1992-07-22 AEG MOBILE COMMUNICATION GmbH Disposition pour commande de volume deans une dispositif téléphonique mains libres
EP0507482A2 (fr) * 1991-04-04 1992-10-07 Nokia Mobile Phones Ltd. Générateur de sonnerie pour appareil téléphonique avec réglage automatique du niveau sonore en function du niveau du bruit ambiant

Cited By (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6744882B1 (en) 1996-07-23 2004-06-01 Qualcomm Inc. Method and apparatus for automatically adjusting speaker and microphone gains within a mobile telephone
GB2351881B (en) * 1998-03-30 2001-06-13 Nec Corp Portable terminal device for controlling received voice level and transmitted voice level
US6760453B1 (en) 1998-03-30 2004-07-06 Nec Corporation Portable terminal device for controlling received voice level and transmitted voice level
GB2351881A (en) * 1998-03-30 2001-01-10 Nec Corp Portable terminal device for controlling received voice level and transmitted voice level
KR100742140B1 (ko) * 1999-03-30 2007-07-24 퀄컴 인코포레이티드 이동전화 스피커와 마이크로폰 이득을 자동으로 조정하는방법 및 장치
WO2000059110A3 (fr) * 1999-03-30 2002-04-04 Qualcomm Inc Procede et appareil pour le reglage automatique de gains de microphone et de haut-parleur au sein d'un telephone mobile
JP4824169B2 (ja) * 1999-03-30 2011-11-30 クゥアルコム・インコーポレイテッド 移動電話内のスピーカ利得およびマイクロフォン利得を自動的に調整するための方法および装置
JP2011130452A (ja) * 1999-03-30 2011-06-30 Qualcomm Inc 移動電話内のスピーカ利得およびマイクロフォン利得を自動的に調整するための方法および装置
EP1811660A1 (fr) 1999-03-30 2007-07-25 QUALCOMM Incorporated Procédé et dispositif pour contrôler automatiquement le gain d'un haut-parleur dans un téléphone mobile
WO2000059110A2 (fr) * 1999-03-30 2000-10-05 Qualcomm Incorporated Procede et appareil pour le reglage automatique de gains de microphone et de haut-parleur au sein d'un telephone mobile
US6959176B1 (en) 1999-04-07 2005-10-25 Siemens Aktiengesellschaft Communications terminal
WO2000060833A1 (fr) * 1999-04-07 2000-10-12 Siemens Aktiengesellschaft Terminal de communication
US7139393B1 (en) 1999-07-01 2006-11-21 Matsushita Electric Industrial Co., Ltd. Environmental noise level estimation apparatus, a communication apparatus, a data terminal apparatus, and a method of estimating an environmental noise level
EP1065653A2 (fr) * 1999-07-01 2001-01-03 Matsushita Electric Industrial Co., Ltd. Dispositif pour l'estimation du niveau de bruit de fond et pour le contrôle du volume d'un appareil de communication
EP1065653A3 (fr) * 1999-07-01 2003-03-19 Matsushita Electric Industrial Co., Ltd. Dispositif pour l'estimation du niveau de bruit de fond et pour le contrôle du volume d'un appareil de communication
WO2001089184A1 (fr) * 2000-05-18 2001-11-22 Ericsson Inc. Gain de signal de communication pouvant etre adapte au bruit
WO2003003572A1 (fr) * 2001-06-28 2003-01-09 Danacom A/S Commande de volume dans une unite d'interface de dispositif de communication
EP1385324A1 (fr) * 2002-07-22 2004-01-28 Siemens Aktiengesellschaft Procédé et dispositif pour la réduction du bruit de fond
KR100678194B1 (ko) * 2002-10-26 2007-02-01 삼성전자주식회사 수신 음성 자동 이득 제어 방법 및 장치
EP2381738A1 (fr) * 2009-01-19 2011-10-26 Huawei Device Co., Ltd. Terminal de communication et dispositif et procédé de réglage du volume adaptatif
EP2381738A4 (fr) * 2009-01-19 2012-08-01 Huawei Device Co Ltd Terminal de communication et dispositif et procédé de réglage du volume adaptatif
CN109889665A (zh) * 2019-02-26 2019-06-14 努比亚技术有限公司 一种音量调节方法、移动终端及存储介质

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