FR2513839A1 - Ambient noise responsive volume control e.g. for car audio - uses discriminator to rectify microphone output for comparison with gain controlled signal to adjust circuit gain - Google Patents
Ambient noise responsive volume control e.g. for car audio - uses discriminator to rectify microphone output for comparison with gain controlled signal to adjust circuit gain Download PDFInfo
- Publication number
- FR2513839A1 FR2513839A1 FR8118193A FR8118193A FR2513839A1 FR 2513839 A1 FR2513839 A1 FR 2513839A1 FR 8118193 A FR8118193 A FR 8118193A FR 8118193 A FR8118193 A FR 8118193A FR 2513839 A1 FR2513839 A1 FR 2513839A1
- Authority
- FR
- France
- Prior art keywords
- gain
- agc
- voltage
- ambient noise
- ratio
- 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.)
- Pending
Links
- 239000003990 capacitor Substances 0.000 claims abstract 3
- 230000007423 decrease Effects 0.000 claims description 3
- 238000011144 upstream manufacturing Methods 0.000 claims 3
- 230000006835 compression Effects 0.000 abstract 1
- 238000007906 compression Methods 0.000 abstract 1
- 238000000034 method Methods 0.000 abstract 1
- 238000010586 diagram Methods 0.000 description 2
- 230000008447 perception Effects 0.000 description 2
- 230000003321 amplification Effects 0.000 description 1
- 239000013256 coordination polymer Substances 0.000 description 1
- 230000006870 function Effects 0.000 description 1
- 238000003199 nucleic acid amplification method Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
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
Landscapes
- Control Of Amplification And Gain Control (AREA)
Abstract
Description
La présente invention a pour objet un perfectionnement des dispositifs
insérés dans les amplificateurs audio qui permettent l'ajustage automati
que du niveau des sources sonores utiles dans les milieux à bruyance va
riable.The subject of the present invention is an improvement of the devices
inserted in audio amplifiers which allow automatic adjustment
that the level of useful sound sources in noisy environments goes
reliable.
Les nombreuses recherches effectuées dans ce domaine ont porté princi
palement sur les moyens proposés pour obtenir une tension proportionnelle
au bruit ambiant malgré la présence de signal utile dans la tension saisie
par le micro. Nous avons nous même proposé une solution qui a fait l'objet d'une demande de brevet publiée en France sous le NO 2 466 901 à laquelle
le lecteur peut se reporter s'il n'est pas familiarisé avec le sujet.The numerous researches carried out in this field have focused
understanding of the means proposed to obtain a proportional voltage
to ambient noise despite the presence of a useful signal in the input voltage
through the microphone. We ourselves have proposed a solution which was the subject of a patent application published in France under NO 2 466 901 to which
the reader can refer if he is not familiar with the subject.
Dans tous les dispositifs connus (y compris le notre) le gain du système d'amplification est proPortionnel au bruit ambiant. Or, l'utilisation pra
tique montre que ces dispositifs sont insuffisants à satisfaire l'utilisa
teur. En effet, lorsqu'on roule en voiture à vitesse constante élevée le bruit est constant mais il est impossible d'écouter la majorité des oeuvres
classiques sans retoucher plusieurs fois le bouton de puissance.Ainsi, même lorsque le bruit est constant le gain doit être rendu variable pour
tenir compte de la dynamique du signal.In all known devices (including ours) the gain of the amplification system is proportional to the ambient noise. However, the use pra
tick shows that these devices are insufficient to satisfy the user
tor. Indeed, when driving in a car at constant high speed the noise is constant but it is impossible to listen to the majority of works
without touching up the power button several times. So even when the noise is constant, the gain must be made variable to
take into account the dynamics of the signal.
D'autre part, dans une ambiance bruyante le confort d'écoute est jugé
optimal lorsque le niveau du signal utile est assez élevé pour être lisible mais pas trop car un signal trop fort est souvent considéré comme une gêne supplémentaire. Dès lors, il est superflu et même génant d'augmenter
le niveau du signal lorsque le bruit augmente si le niveau du signal est déja élevé par rapport au bruit.On the other hand, in a noisy atmosphere, listening comfort is judged
optimal when the level of the useful signal is high enough to be readable but not too much because too strong a signal is often considered as an additional annoyance. Therefore, it is superfluous and even annoying to increase
the signal level when the noise increases if the signal level is already high compared to the noise.
Ainsi, les systèmes connus ne fonctionnent pas de manière conforme à l'attente de l'auditeur. La figure 1 en représente schéma général. Ils
ne diffèrent que dans le mode d'optention de la tension de bruit que nous
avons schématisé par un discriminateur D à la sortie duquel on dispose
d'une tension redressée proportionnelle au bruit ambiant soit VB. Un micro MC recueille l'ambiance sonore composée de signal utile S et de bruit ambiant nuisible B. Le discriminateur D sépare les composantes de signal utile et de bruit ambiant. A la sortie du discriminateur, la tension VB est appliquée directement via un interrupteur chargé de mettre le système hors fonction, comme tension de commande VC de l'AGC. Ainsi, la source de signal SE appliquée à l'entée de l'AGC est amplifiée selon VC donc VB.Thus, the known systems do not operate in accordance with the expectation of the auditor. Figure 1 shows a general diagram. They
differ only in the mode of option of the noise voltage that we
have schematized by a discriminator D at the exit of which we have
of a rectified voltage proportional to the ambient noise, ie VB. A microphone MC collects the sound environment composed of useful signal S and harmful ambient noise B. The discriminator D separates the components of useful signal and ambient noise. At the output of the discriminator, the voltage VB is applied directly via a switch responsible for putting the system off, as the control voltage VC of the AGC. Thus, the signal source SE applied to the input of the AGC is amplified according to VC therefore VB.
Il est ensuite appliqué à un amplificateur de puissance AP puis à un haut parleur HP. Ainsi, de tels systèmes sont insuffisants à satisfaire l'auditeur. It is then applied to an AP power amplifier and then to an HP speaker. Thus, such systems are insufficient to satisfy the listener.
Le dispositif suivant l'invention permet d'élaborer à partir des niveaux de signal et de bruit une tension de commande VC plus apte à piloter l'AGC en permettant d'obtenir un résultat plus conforme à l'attente -de l'auditeur. The device according to the invention makes it possible to develop, from the signal and noise levels, a control voltage VC more suitable for controlling the AGC while making it possible to obtain a result more in accordance with the expectation of the listener.
Un exemple de réalisation est illustré figure 2. Un comparateur CP compare une tension de signal VS prélevée après ï'AGC et préalablement redressée et mise à niveau par P à une tension de bruit VB. Le rapport de comparaison RS/RB qui peut être variable est déterminé en fonction du rapport signal utile/ bruit ambiant désiré. Le rapport choisi peut être appelé niveau de perception claire. Tant que VS/VB est inférieur à RS/RB la sortie du comparateur est à l'état bas, le commutateur T (ici un transistor NPN) est ouvert eut VC tend vers VB avec la constante de temps (R1+R2)C. Dès que
VS/VB atteint RS/RB, la sortie du comparateur passe à l'état haut, T est passant, C se décharge dans R1, VC baisse, le gain de l'AGC diminue ainsi que VS.Dès que le rapport VS/VB descend au dessous de RS/RB le comparateur change d'état et le cycle de remontée reprend. En jouant sur les constantes de temps par R1 et R2 on peut obtenir soit une variation lente du gain soit un fonctionnement en compresseur de dynamique asservi au bruit.An exemplary embodiment is illustrated in FIG. 2. A comparator CP compares a signal voltage VS taken after the AGC and previously rectified and leveled by P with a noise voltage VB. The RS / RB comparison ratio which can be variable is determined as a function of the desired signal to ambient noise ratio desired. The ratio chosen can be called the level of clear perception. As long as VS / VB is less than RS / RB, the comparator output is low, the switch T (here an NPN transistor) is open, VC tends towards VB with the time constant (R1 + R2) C. As soon as
VS / VB reaches RS / RB, the comparator output goes high, T is passing, C discharges in R1, VC decreases, the gain of the AGC decreases as well as VS. As soon as the VS / VB ratio goes below RS / RB the comparator changes state and the ascent cycle resumes. By playing on the time constants by R1 and R2 you can obtain either a slow variation of the gain or an operation in dynamic compressor controlled by noise.
Dans une variante, la tension VS peut être comparée à une tension VM comprenant du signal et du bruit. Il suffit alors dans le calcul du rapport
RS/RB de prendre en compte que VM= VS + VB;. In a variant, the voltage VS can be compared to a voltage VM comprising signal and noise. It suffices then in the calculation of the ratio
RS / RB to take into account that VM = VS + VB ;.
Dans une autre variante compatible avec la précédente, on peut appliquer en R2 au lieu de VB une tension fixe VF apte à donner à l'AGC son gain maximum.On obtient alors un fonctionnement plus efficace sur le plan du rapport signal utile/ bruit ambiant mais une mise en avant des bruits de fond sur certaines modulationsrend l'écoute moins agréable. On choisira cette variante lorsque les modulations a traiter auront une dynamique importante et que la lisibilité du message sera plus importante que son esthétique. In another variant compatible with the previous one, it is possible to apply in R2 instead of VB a fixed voltage VF capable of giving the AGC its maximum gain. This then gives more efficient operation in terms of the useful signal / ambient noise ratio but highlighting background noise on certain modulations makes listening less pleasant. This variant will be chosen when the modulations to be treated will have a significant dynamic and the readability of the message will be more important than its aesthetics.
Le gain minimum de l'AGC est déterminé par le potentiel du point M. Si l'on désire que le système ne rentre en fonction que pour relever le niveau du signal lorsqu'il descend au dessous du seuil de perception clair on fixe le gain minimum de l'AGC à 1. Par contre si l'on désire limiter le niveau de VS quelque soit VE on fixe le gain minimum de l'AGC à 0. The minimum gain of the AGC is determined by the potential of the point M. If you want the system to come into operation only to raise the signal level when it drops below the clear perception threshold, you set the gain minimum of the AGC to 1. On the other hand if one wishes to limit the level of VS whatever is VE one fixes the minimum gain of the AGC to 0.
Ce dispositif ne prend pas en compte la manière dont est obtenue V3. This device does not take into account the way in which V3 is obtained.
Il est compatible avec tous les systèmes fonctionnant suivant le ghéma de la figure 1. It is compatible with all systems operating according to the diagram in Figure 1.
Claims (2)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR8118193A FR2513839A1 (en) | 1981-09-28 | 1981-09-28 | Ambient noise responsive volume control e.g. for car audio - uses discriminator to rectify microphone output for comparison with gain controlled signal to adjust circuit gain |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR8118193A FR2513839A1 (en) | 1981-09-28 | 1981-09-28 | Ambient noise responsive volume control e.g. for car audio - uses discriminator to rectify microphone output for comparison with gain controlled signal to adjust circuit gain |
Publications (1)
Publication Number | Publication Date |
---|---|
FR2513839A1 true FR2513839A1 (en) | 1983-04-01 |
Family
ID=9262512
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
FR8118193A Pending FR2513839A1 (en) | 1981-09-28 | 1981-09-28 | Ambient noise responsive volume control e.g. for car audio - uses discriminator to rectify microphone output for comparison with gain controlled signal to adjust circuit gain |
Country Status (1)
Country | Link |
---|---|
FR (1) | FR2513839A1 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2579842A1 (en) * | 1985-03-27 | 1986-10-03 | Carpentier Claude | Device for compensating the surrounding noise in an audio amplifier |
US4644292A (en) * | 1984-05-31 | 1987-02-17 | Pioneer Electronic Corporation | Automatic gain and frequency characteristic control unit in audio device |
WO1988001453A1 (en) * | 1986-08-13 | 1988-02-25 | Aranda Applied Research & Tech | Adaptive gain control amplifier |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2405609A1 (en) * | 1977-10-06 | 1979-05-04 | Gamelin Thierry | Volume control system for public address network - uses detected level of output sound to control amplification of broadcast |
FR2435879A1 (en) * | 1978-08-26 | 1980-04-04 | Viva Co | APPARATUS FOR AUTOMATIC SOUND VOLUME ADJUSTMENT BASED ON VARIATIONS IN THE LEVEL OF AMBIENT NOISE |
-
1981
- 1981-09-28 FR FR8118193A patent/FR2513839A1/en active Pending
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2405609A1 (en) * | 1977-10-06 | 1979-05-04 | Gamelin Thierry | Volume control system for public address network - uses detected level of output sound to control amplification of broadcast |
FR2435879A1 (en) * | 1978-08-26 | 1980-04-04 | Viva Co | APPARATUS FOR AUTOMATIC SOUND VOLUME ADJUSTMENT BASED ON VARIATIONS IN THE LEVEL OF AMBIENT NOISE |
Non-Patent Citations (1)
Title |
---|
RADIO FERNSEHEN ELEKTRONIK, volume 29, no. 8, 1980 (BERLIN, DE) "Störgeräusabhängige automatische Lautstärkesteuerung", page 539 * |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4644292A (en) * | 1984-05-31 | 1987-02-17 | Pioneer Electronic Corporation | Automatic gain and frequency characteristic control unit in audio device |
FR2579842A1 (en) * | 1985-03-27 | 1986-10-03 | Carpentier Claude | Device for compensating the surrounding noise in an audio amplifier |
WO1988001453A1 (en) * | 1986-08-13 | 1988-02-25 | Aranda Applied Research & Tech | Adaptive gain control amplifier |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
EP1629463B1 (en) | Method, apparatus and computer program for calculating and adjusting the perceived loudness of an audio signal | |
US4476571A (en) | Automatic sound volume control device | |
EP1923994B1 (en) | Audio compressor | |
JP5192544B2 (en) | Acoustic processing using auditory scene analysis and spectral distortion | |
US4395600A (en) | Auditory subliminal message system and method | |
US8812308B2 (en) | Apparatus and method for modifying an input audio signal | |
FR2478904A1 (en) | GAIN CONTROL CIRCUIT | |
EP0312569A1 (en) | Method and apparatus for improving voice intelligibility in high noise environments. | |
FR2719173A1 (en) | Communication apparatus with noise adjustment. | |
FR2513839A1 (en) | Ambient noise responsive volume control e.g. for car audio - uses discriminator to rectify microphone output for comparison with gain controlled signal to adjust circuit gain | |
EP0376866B1 (en) | Control device for a hands-free half duplex telephone set | |
FR2464167A1 (en) | VOLUME CONTROL SYSTEM FOR A VOICE WARNING SYSTEM FOR DIFFUSION OF INFORMATION IN A MOTOR VEHICLE | |
KR20200026896A (en) | Voice signal leveling | |
JP3131226B2 (en) | Hearing aid with improved percentile predictor | |
FR2635680A1 (en) | HEARING AID | |
FR2686757A1 (en) | CURRENT MODULATOR OF A TELEPHONE LINE. | |
JPS6257040B2 (en) | ||
EP0305301B1 (en) | Signal compressor circuit, in particular for telephone set | |
EP1835487B1 (en) | Method, apparatus and computer program for calculating and adjusting the perceived loudness of an audio signal | |
FR2561225A1 (en) | METHOD AND DEVICE FOR BRAKING A STAIRCASE | |
US2903515A (en) | Device for selective compression and automatic segmentation of a speech signal | |
FR2479615A1 (en) | RECEIVER APPARATUS SUCH AS A RADIO RECEIVER OR TRANSCEIVER | |
US3735275A (en) | Dynamic presence filter | |
EP0391469B1 (en) | Control circuit for amplified listening | |
FR2529727A1 (en) | Device for automatic adjustment of the sound level of a source of useful sound as a function of the ambient noise. |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
ST | Notification of lapse | ||
AR | Application made for restoration | ||
BR | Restoration of rights |