EP0103256B1 - Method and apparatus to eliminate both acoustical and mechanical vibrational effects - Google Patents
Method and apparatus to eliminate both acoustical and mechanical vibrational effects Download PDFInfo
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- EP0103256B1 EP0103256B1 EP83108765A EP83108765A EP0103256B1 EP 0103256 B1 EP0103256 B1 EP 0103256B1 EP 83108765 A EP83108765 A EP 83108765A EP 83108765 A EP83108765 A EP 83108765A EP 0103256 B1 EP0103256 B1 EP 0103256B1
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- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
- G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/175—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound
- G10K11/178—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound by electro-acoustically regenerating the original acoustic waves in anti-phase
- G10K11/1785—Methods, e.g. algorithms; Devices
- G10K11/17857—Geometric disposition, e.g. placement of microphones
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- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
- G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/175—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound
- G10K11/178—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound by electro-acoustically regenerating the original acoustic waves in anti-phase
- G10K11/1781—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound by electro-acoustically regenerating the original acoustic waves in anti-phase characterised by the analysis of input or output signals, e.g. frequency range, modes, transfer functions
- G10K11/17821—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound by electro-acoustically regenerating the original acoustic waves in anti-phase characterised by the analysis of input or output signals, e.g. frequency range, modes, transfer functions characterised by the analysis of the input signals only
- G10K11/17823—Reference signals, e.g. ambient acoustic environment
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- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
- G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/175—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound
- G10K11/178—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound by electro-acoustically regenerating the original acoustic waves in anti-phase
- G10K11/1785—Methods, e.g. algorithms; Devices
- G10K11/17853—Methods, e.g. algorithms; Devices of the filter
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- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
- G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/175—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound
- G10K11/178—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound by electro-acoustically regenerating the original acoustic waves in anti-phase
- G10K11/1787—General system configurations
- G10K11/17873—General system configurations using a reference signal without an error signal, e.g. pure feedforward
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- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
- G10K2210/00—Details of active noise control [ANC] covered by G10K11/178 but not provided for in any of its subgroups
- G10K2210/10—Applications
- G10K2210/129—Vibration, e.g. instead of, or in addition to, acoustic noise
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- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
- G10K2210/00—Details of active noise control [ANC] covered by G10K11/178 but not provided for in any of its subgroups
- G10K2210/30—Means
- G10K2210/301—Computational
- G10K2210/3018—Correlators, e.g. convolvers or coherence calculators
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- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
- G10K2210/00—Details of active noise control [ANC] covered by G10K11/178 but not provided for in any of its subgroups
- G10K2210/30—Means
- G10K2210/301—Computational
- G10K2210/3025—Determination of spectrum characteristics, e.g. FFT
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- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
- G10K2210/00—Details of active noise control [ANC] covered by G10K11/178 but not provided for in any of its subgroups
- G10K2210/30—Means
- G10K2210/301—Computational
- G10K2210/3028—Filtering, e.g. Kalman filters or special analogue or digital filters
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- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
- G10K2210/00—Details of active noise control [ANC] covered by G10K11/178 but not provided for in any of its subgroups
- G10K2210/30—Means
- G10K2210/301—Computational
- G10K2210/3042—Parallel processing
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- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
- G10K2210/00—Details of active noise control [ANC] covered by G10K11/178 but not provided for in any of its subgroups
- G10K2210/30—Means
- G10K2210/301—Computational
- G10K2210/3045—Multiple acoustic inputs, single acoustic output
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- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
- G10K2210/00—Details of active noise control [ANC] covered by G10K11/178 but not provided for in any of its subgroups
- G10K2210/30—Means
- G10K2210/321—Physical
- G10K2210/3216—Cancellation means disposed in the vicinity of the source
Definitions
- the subject of the present invention is a device for eliminating the effects of acoustic or mechanical vibrations, in particular with a view to creating a zone of silence with respect to one or more sources of noise or preventing the transmission of mechanical vibrations produced by one or more sources of undesirable mechanical vibrations.
- damping vibrations is often difficult to achieve insofar as it is possible to stifle a known pure frequency vibration emitted by a well-defined source, it is much more difficult to stifle a set of vibrations whose the characteristics are only known globally.
- the signal generation device comprises two inverse Fourier transform calculators and a control device which operates by comparing the same signal obtained from the single sensor at successive instants by memorizing this signal in two memories supplied in series.
- the information obtained under these conditions is necessarily quite poor and in particular includes only amplitude information without phase information, which only allows very average results to be obtained.
- the present invention relates to a device according to claim 1. Its characteristics and advantages are specified in the following description and in relation to the figures below referenced.
- FIG. 1 presents a diagram of a device for canceling the effects of acoustic or mechanical vibrations in connection with the sources causing them.
- FIG. 2 shows the diagram of a correlation module for a device according to the invention.
- FIG. 3 presents the diagram of the principle of cancellation according to the invention in digital form.
- the cancellation device is essentially intended to eliminate the effects of unwanted acoustic or mechanical vibrations, from the signals obtained from at least two sensors referenced 1 and 2 in FIG. 1 in the case of elimination of vibrations. acoustic and 1 'and 2' in the case of elimination of mechanical vibrations. It therefore aims to create a zone z protected from the noise created by an AP source in the first hypothesis and to avoid the transmission of mechanical vibrations from an AP 'apparatus to its environment via the EL links which connect it to the latter. , in particular its base or its support points, in the second hypothesis.
- a sensor 1 is placed upstream of a zone z which one wishes to protect in space Z where the source AP exhibits its annoying acoustic effects and a sensor 2 is placed against on or near from the AP source so as to capture the noise emissions.
- the sensors 1 and 2 are for example microphones, the sensor 1 is possibly a room microphone and the microphone 2 a directional microphone, or even an accelerometer if the noises are of mechanical origin.
- a sensor 1 ′ is placed on or against the connection (s) EL by which the mechanical vibrations created by the apparatus AP ′ are capable of being transmitted to its environment, not shown.
- a sensor 2 ' is placed against or on the apparatus AP', it being understood that at least one servo-controlled damper AM is inserted between each link EL and the apparatus AP 'to avoid transmissions of mechanical vibrations.
- the sensors 1 ′ and 2 ′ are then for example accelerometers
- the damper AM is for example a damper 11 controlled by electrical control and it is inserted for example between the frame of the apparatus AP ′ and the base serving as a support which then forms the EL bond.
- sensors 1 and 2 or l 'and 2' can vary according to the existing constraints, however insofar as the principle remains the same, a single sensor 1 and a single sensor 2, or a single sensor 1 'and a single sensor 2 ′ is taken into account in the following description.
- the invention uses the signals b '(t) generated by the sensor 2, or 2' as the case may be and the signals b (t) generated by the sensor 1, or possibly 1 ', to produce a signal in opposition to phase with signal b (t) so to inject it either into at least one loudspeaker HP placed downstream of the sensor 1 relative to the apparatus AP so as to create downstream of this loudspeaker the zone z protected from noise, or in the control circuit not shown of the AM shock absorber.
- the signal b '(t) of the duly amplified sensor 2 is applied to a plurality of narrow-band filters 3a to 3n, called line filters, which are individually centered on different frequencies distributed in the auditory disturbing spectrum.
- Each line filter 3 provides a reference b '(f) representing the energy spectral density of the noise received by the sensor 2 for the frequency considered as b' (fa) for the line filter 3a centered on the frequency fa.
- Each filter 3 is connected to an input of a correlation module 4 which is specific to it and which has a second input connected to the output of the sensor 1 from which it therefore receives the signal b (t).
- the correlation modules 4 are for example of the type described in French patent 2215005 of the Applicant and presented in FIG. 2.
- the application of the signal S (t) to the acoustic transducer HP causes the emission by the latter of signals in phase opposition with those coming from the noise source AP in the zone z where this transducer is effective.
- the application of the signal S (t) to the control circuit, not shown, of the controlled damper AM causes the creation in this damper of mechanical vibrations in phase opposition with the mechanical vibrations coming from the apparatus AP ', which are thus thus canceled at the level of the EL connection, for example at the level of the base carrying the apparatus.
- line filters 3 are necessarily limited as long as one does not use a signal conversion in digital form and it is therefore the filter adjustment possibilities which make it possible to select the lines intended to make the object of correction, since in the most general case, only the energy of certain lines is to be taken into account, the others being either negligible or nonexistent.
- An attenuation device applying the method according to the invention can advantageously be implemented after conversion of the signals produced by the sensors from an analog form to a digital form, taking advantage of the advantages brought by the Fourier transformations and more particularly the fast Fourier transformations (FFT).
- FFT fast Fourier transformations
- each sensor 1 or 2 is connected to an appropriate analog-digital converter 7 and each converter supplies the results of its conversions to a set 8 ′ constituted by a computer capable of calculating a fast double Fourier transform FFT1 , FFT2 from the signals received from each of the converters to deduce therefrom a signal summing the correlated corrections made by each line at the transform point.
- a set 8 ′ constituted by a computer capable of calculating a fast double Fourier transform FFT1 , FFT2 from the signals received from each of the converters to deduce therefrom a signal summing the correlated corrections made by each line at the transform point.
- This sum signal is then the subject of a fast inverse Fourier transformation, the result of which is applied to the loudspeaker HP or to the damper AM via a digital-analog converter (9) and of possible amplifiers in order to obtain the previously mentioned effects.
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- Engineering & Computer Science (AREA)
- Acoustics & Sound (AREA)
- Multimedia (AREA)
- Soundproofing, Sound Blocking, And Sound Damping (AREA)
- Measurement Of Mechanical Vibrations Or Ultrasonic Waves (AREA)
Description
La présente invention a pour objet un dispositif pour l'élimination des effets de vibrations acoustiques ou mécaniques, notamment en vue de créer une zone de silence vis-à-vis d'une ou de plusieurs sources de bruits ou d'empêcher la transmission de vibrations mécaniques produites par une ou plusieurs sources de vibrations mécaniques indésirables.The subject of the present invention is a device for eliminating the effects of acoustic or mechanical vibrations, in particular with a view to creating a zone of silence with respect to one or more sources of noise or preventing the transmission of mechanical vibrations produced by one or more sources of undesirable mechanical vibrations.
L'attenuation des vibrations acoustiques ou mécaniques indésirables s'effectue classiquement à l'aide de dispositifs amortisseurs sonores ou mécaniques qui sont insérés entre la ou les sources produisant ces vibrations et l'environnement que l'on veut protéger. Ces amortisseurs absorbent les vibrations et agissent donc comme des filtres coupe-bande pour la bande de fréquences où les vibrations que l'on veut éliminer se produisent.The attenuation of unwanted acoustic or mechanical vibrations is conventionally carried out using sound or mechanical damping devices which are inserted between the source or sources producing these vibrations and the environment which one wishes to protect. These dampers absorb vibrations and therefore act as notch filters for the frequency band where the vibrations to be eliminated occur.
En pratique, l'amortissement des vibrations est souvent difficile à réaliser dans la mesure où si l'on sait bien étouffer une vibration de fréquence pure connue émise par une source bien déterminée, il est beaucoup plus délicat d'étouffer un ensemble de vibrations dont les caractéristiques ne sont connues que globalement.In practice, damping vibrations is often difficult to achieve insofar as it is possible to stifle a known pure frequency vibration emitted by a well-defined source, it is much more difficult to stifle a set of vibrations whose the characteristics are only known globally.
Or, il existe de nombreux cas où l'on souhaite soit créer une zone de silence dans un environnement rendu bruyant par l'existence de sources plus où moins localisées ou connues, tel par exemple une salle rendue bruyante par des machines ou un poste de pilotage, soit encore éliminer les vibrations transmises par une machine à son environnement.However, there are many cases where one wishes either to create a zone of silence in an environment made noisy by the existence of more or less localized or known sources, such as for example a room made noisy by machines or a workstation. control, or even eliminate the vibrations transmitted by a machine to its environment.
Il est connu de la demande de brevet européen EP-A-0043.565 d'utiliser, pour réduire les bruits provenant d'un appareillage électrique, un dispositif dans lequel un senseur unique placé sur cet appareillage capte ces bruits qui sont ensuite numérisés puis appliqués à un dispositif générateur de signaux numériques adaptés pour réduire les bruits; ces signaux numériques sont convertis en signaux analogiques qui sont appliqués à un transducteur placé sur l'appareillage dont on vent réduire le bruit. Pour commander les convertisseurs analogique/numérique et numérique/ analogique nécessaires on peut utiliser soit un signal obtenu à partir du capteur de bruit, soit un signal obtenu à partir d'un second capteur qui ne sert qu'à délivrer ce signal de synchronisation. Le dispositif de génération des signaux comporte deux calculateurs de transformée de Fourier inverses l'un de l'autre et un dispositif de contrôle qui fonctionne en comparant le même signal obtenu à partir du capteur unique à des instants successifs en mémorisant ce signal dans deux mémoires alimentées en série. L'information obtenue dans ces conditions est nécessairement assez pauvre et ne comporte en particulier que des informations d'amplitude sans information de phase, ce ne qui permet d'obtenir que des résultats très moyens.It is known from European patent application EP-A-0043,565 to use, to reduce the noises coming from an electrical apparatus, a device in which a single sensor placed on this apparatus collects these noises which are then digitized and then applied to a digital signal generating device adapted to reduce noise; these digital signals are converted into analog signals which are applied to a transducer placed on the equipment, the noise of which can be reduced. To control the necessary analog / digital and digital / analog converters, it is possible to use either a signal obtained from the noise sensor, or a signal obtained from a second sensor which only serves to deliver this synchronization signal. The signal generation device comprises two inverse Fourier transform calculators and a control device which operates by comparing the same signal obtained from the single sensor at successive instants by memorizing this signal in two memories supplied in series. The information obtained under these conditions is necessarily quite poor and in particular includes only amplitude information without phase information, which only allows very average results to be obtained.
La présente l'invention a pour objet un dispositif selon la revendication 1. Ses caractéristiques et ses avantages sont précisés dans la suite de la description et en relation avec les figures ci-dessous référencées.The present invention relates to a device according to claim 1. Its characteristics and advantages are specified in the following description and in relation to the figures below referenced.
La figure 1 présente un schéma d'un dispositif d'annulation des effets de vibrations acoustiques ou mécaniques en liaison avec les sources les occasionnant.FIG. 1 presents a diagram of a device for canceling the effects of acoustic or mechanical vibrations in connection with the sources causing them.
La figure 2 présente le schéma d'un module de corrélation pour dispositif selon l'invention.FIG. 2 shows the diagram of a correlation module for a device according to the invention.
La figure 3 présente le schéma de principe d'annulation elon l'invention sous une forme numérique.FIG. 3 presents the diagram of the principle of cancellation according to the invention in digital form.
Le dispositif d'annulation selon l'invention est essentiellement destiné à éliminer les effets des vibrations acoustiques ou mécaniques indésirables, à partir des signaux obtenus d'au moins deux capteurs référencés 1 et 2 sur la figure 1 dans le cas d'élimination de vibrations acoustiques et 1' et 2' dans le cas d'élimination de vibrations mécaniques. Il vise donc a créer une zone z à l'abri du bruit créé par une source AP dans la première hypothèse et à éviter la transmission des vibrations mécaniques d'un appareillage AP' à son environnement via les liaisons EL qui le relient à ce dernier, en particulier son socle ou ses points d'appui, dans la seconde hypothèse.The cancellation device according to the invention is essentially intended to eliminate the effects of unwanted acoustic or mechanical vibrations, from the signals obtained from at least two sensors referenced 1 and 2 in FIG. 1 in the case of elimination of vibrations. acoustic and 1 'and 2' in the case of elimination of mechanical vibrations. It therefore aims to create a zone z protected from the noise created by an AP source in the first hypothesis and to avoid the transmission of mechanical vibrations from an AP 'apparatus to its environment via the EL links which connect it to the latter. , in particular its base or its support points, in the second hypothesis.
Dans le premier cas, un capteur 1, est placé en amont d'une zone z que l'on veut protéger dans l'espace Z où la source AP fait sentir ses effets acoutiques gênants et un capteur 2 est placé contre sur ou à proximité de la source AP de manière à en capter les émissions sonores.In the first case, a sensor 1 is placed upstream of a zone z which one wishes to protect in space Z where the source AP exhibits its annoying acoustic effects and a
Les capteurs 1 et 2 sont par exemple des microphones, le capteur 1 est éventuellement un microphone d'ambiance et le microphone 2 un microphone directif, ou encore un accéléromètre si les bruits sont d'origine mécaniques.The
Dans le second cas, un capteur 1' est placé sur ou contre la ou les liaisons EL par lequel les vibrations mécaniques créées par l'appareillage AP' sont susceptibles d'être transmises à son environnement non figuré. Un capteur 2' est placé contre ou sur l'appareillage AP', étant entendu qu'au moins un amortisseur asservi AM est inséré entre chaque liaison EL et l'appareillage AP' pour éviter les transmissions de vibrations mécaniques.In the second case, a sensor 1 ′ is placed on or against the connection (s) EL by which the mechanical vibrations created by the apparatus AP ′ are capable of being transmitted to its environment, not shown. A sensor 2 'is placed against or on the apparatus AP', it being understood that at least one servo-controlled damper AM is inserted between each link EL and the apparatus AP 'to avoid transmissions of mechanical vibrations.
Les capteurs 1' et 2' sont alors par exemple des accéléromètres, l'amortisseur AM est par exemple un amortisseur 11 asservi à commande électrique et il est inséré par exemple entre le bâti de l'appareillage AP' et le socle servant de support qui forme alors la liaison EL.The sensors 1 ′ and 2 ′ are then for example accelerometers, the damper AM is for example a damper 11 controlled by electrical control and it is inserted for example between the frame of the apparatus AP ′ and the base serving as a support which then forms the EL bond.
Bien entendu le nombre de capteurs 1 et 2 ou l' et 2' peut varier en fonction des contraintes existantes, toutefois dans la mesure où le principe reste le même un seul capteur 1 et un seul capteur 2, ou un seul capteur 1' et un seul capteur 2' sont pris en compte dans la suite de la description.Of course the number of
Selon l'invention ou exploite les signaux b'(t) générés par le capteur 2, ou 2' suivant le cas et les signaux b(t) générés par le capteur 1, ou éventuellement 1', pour produire un signal en opposition de phase avec le signal b(t) de manière à l'injecter soit dans au moins un haut-parleur HP placé en aval du capteur 1 par rapport à l'appareillage AP de manière à créer en aval de ce haut-parleur la zone z protégée du bruit, soit dans le circuit de commande non figuré de l'amortisseur AM.According to the invention or uses the signals b '(t) generated by the
En ce but, le signal b'(t) du capteur 2 dûment amplifié est appliqué à une pluralité de filtres à bande étroite 3a à 3n, dits de raie, qui sont individuellement centrés sur des fréquences différentes réparties dans le spectre auditivement gênant.For this purpose, the signal b '(t) of the duly amplified
Chaque filtre de raie 3 fournit une référence b'(f) représentant la densité spectrale energétique du bruit reçu par le capteur 2 pour la fréquence considérée tel b'(fa) pour le filtre de raie 3a centré sur la fréquence fa. Chaque filtre 3 est relié à une entrée d'un module de corrélation 4 qui lui est propre et qui a une seconde entrée reliée à la sortie du capteur 1 dont il reçoit donc le signal b(t).Each line filter 3 provides a reference b '(f) representing the energy spectral density of the noise received by the
Les modules de corrélation 4 sont par exemple du type décrit dans le brevet français 2215005 de la Demanderesse et présenté en figure 2.The correlation modules 4 are for example of the type described in French patent 2215005 of the Applicant and presented in FIG. 2.
Chaque module de corrélation 4, tel 4a, est alors composé:
- - d'un circuit de
normalisation 48 de type usuel assurant la normalisation en puissance du signal fourni par la sortie du filtre de raie 3 associé, - - d'un
déphaseur 40 relié à la sortie du circuit denormalisation 48 auquel il est associé et dont il reçoit un signal b' (fa), - - de deux multiplicateurs d'entrée 41, 42 dont l'un 41 a ses entrées respectivement reliées au capteur 1 et à la sortie du
filtre 3a, alors que l'autre a ses entrées respectivement reliées au capteur 1 et à la sortie dudéphaseur 40, - - de deux
intégrateurs 43 et 44 respectivement insérés en sortie des multiplicateurs d'entrée 41 et 42, - - de deux multiplicateurs de
sortie 45 et 46, dont l'un 45 a ses entrées respectivement reliées en sortie de l'intégrateur 43 et dufiltre 3a alors que l'autre 46 à ses entrées respectivement reliées en sortie du capteur 1 et en sortie dudéphaseur 40, - - un additionneur 47 relié par ses entrées aux sorties des multiplicateurs de
sortie 45 et 46 de manière à fournir un signal de sortie b(fa) qui correspond à la correction à apporter au signal b(t) pour éliminer la composante du bruit pour la fréquence fa sur laquelle est entrée le filtre deraie 3a considéré.
- a
normalization circuit 48 of the usual type ensuring the power normalization of the signal supplied by the output of the associated line filter 3, - a
phase shifter 40 connected to the output of thenormalization circuit 48 with which it is associated and from which it receives a signal b ′ (fa), - - two
input multipliers 41, 42 one of which has its inputs respectively connected to the sensor 1 and to the output of thefilter 3a, while the other has its inputs respectively connected to the sensor 1 and to the output of thephase shifter 40, - - two
integrators 43 and 44 respectively inserted at the output of theinput multipliers 41 and 42, - - two output multipliers 45 and 46, one of which 45 has its inputs respectively connected to the output of the
integrator 43 and of thefilter 3a while the other 46 to its inputs respectively connected at the output of the sensor 1 and at the output of thephase shifter 40, - - an adder 47 connected by its inputs to the outputs of the
45 and 46 so as to provide an output signal b (fa) which corresponds to the correction to be made to the signal b (t) to eliminate the noise component for the frequency fa on which theoutput multipliers line filter 3a considered is entered.
L'ensemble 8 constituant le dispositif d'atténuation selon l'invention qui comprend donc les filtres 3, les modules de corrélation 4 comporte de plus un additionneur 5 aux entrées duquel sont reliées les modules de corrélation 4 de manière à additionner les signaux de correction b (fa), b (fb), ...b(fn) obtenus de ces modules pour générer un signal S(t) à transmettre soit au transducteur HP ici symbolisé par un haut-parleur, soit à l'amortisseur AM.The
L'application du signal S(t) au transducteur acoustique HP entraîne l'émission par ce dernier de signaux en opposition de phase avec ceux issus de la source de bruits AP dans la zone z où ce transducteur est efficace.The application of the signal S (t) to the acoustic transducer HP causes the emission by the latter of signals in phase opposition with those coming from the noise source AP in the zone z where this transducer is effective.
L'application du signal S(t) au circuit de commande non figuré de l'amortisseur asservi AM entraîne la création dans cet amortisseur de vibrations mécaniques en opposition de phase avec les vibrations mécaniques issues de l'appareillage AP', qui sont donc ainsi annulées au niveau de la liaison EL, par exemple au niveau du socle portant l'appareillage.The application of the signal S (t) to the control circuit, not shown, of the controlled damper AM causes the creation in this damper of mechanical vibrations in phase opposition with the mechanical vibrations coming from the apparatus AP ', which are thus thus canceled at the level of the EL connection, for example at the level of the base carrying the apparatus.
Bien entendu dans la pratique le nombre de filtres de raie 3 est nécessairement limité tant que l'on n'utilise pas une conversion de signaux sous forme numérique et ce sont donc les possibilités de réglage des filtres qui permettent de sélectionner les raies destinées à faire l'objet de correction, puisque dans le cas le plus général, seule l'énergie de certaines raies est à prendre en compte, les autres étant soient négligeables soient inexistantes.Of course in practice the number of line filters 3 is necessarily limited as long as one does not use a signal conversion in digital form and it is therefore the filter adjustment possibilities which make it possible to select the lines intended to make the object of correction, since in the most general case, only the energy of certain lines is to be taken into account, the others being either negligible or nonexistent.
Un dispositif d'atténuation appliquant le procédé selon l'invention peut avantageusement être mis en oeuvre après conversion des signaux produits par les capteurs d'une forme analogique en une forme numérique, en profitant des avantages apportés par les transformations de Fourier et plus particulièrement les transformations de Fourier rapides (FFT).An attenuation device applying the method according to the invention can advantageously be implemented after conversion of the signals produced by the sensors from an analog form to a digital form, taking advantage of the advantages brought by the Fourier transformations and more particularly the fast Fourier transformations (FFT).
En effet, il est alors possible d'obtenir l'équivalent d'un nombre élevé de filtres de raie répartis dans la bande utile, par exemple l'équivalent de mille filtres de raie à l'aide d'une transformée de mille points, ce qui dans l'exemple numérique proposé plus haut permet de corriger l'ensemble des fréquences entières de la bande utile.Indeed, it is then possible to obtain the equivalent of a large number of line filters distributed in the useful band, for example the equivalent of a thousand line filters using a thousand point transform, which in the digital example proposed above makes it possible to correct all of the whole frequencies of the useful band.
Ainsi que le montre la figure 2 chaque capteur 1 ou 2 est relié à un convertisseur analogique- numérique 7 approprié et chaque convertisseur fournit les résultats de ses conversions à un ensemble 8'constitué par un calculateur apte à calculer une double transformée de Fourier rapide FFT1, FFT2 à partir des signaux reçus de chacun des convertisseurs pour en déduire un signal faisant la somme des corrections corrélées effectuées par chaque raie au point de transformée.As shown in FIG. 2, each
Ce signal somme est alors objet d'une transformation de Fourier rapide inverse dont le résultat est -appliqué au haut-parleur HP où à l'amortisseur AM via un convertisseur numérique-analogique (9) et d'éventuels amplificateurs afin d'obtenir les effets précédemment évoqués.This sum signal is then the subject of a fast inverse Fourier transformation, the result of which is applied to the loudspeaker HP or to the damper AM via a digital-analog converter (9) and of possible amplifiers in order to obtain the previously mentioned effects.
Claims (4)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR8215280A FR2533057B1 (en) | 1982-09-09 | 1982-09-09 | METHOD AND DEVICES FOR ELIMINATING ACOUSTIC OR MECHANICAL VIBRATION EFFECTS |
FR8215280 | 1982-09-09 |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0103256A1 EP0103256A1 (en) | 1984-03-21 |
EP0103256B1 true EP0103256B1 (en) | 1988-02-24 |
Family
ID=9277320
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP83108765A Expired EP0103256B1 (en) | 1982-09-09 | 1983-09-06 | Method and apparatus to eliminate both acoustical and mechanical vibrational effects |
Country Status (5)
Country | Link |
---|---|
EP (1) | EP0103256B1 (en) |
AU (1) | AU1874983A (en) |
CA (1) | CA1208351A (en) |
DE (1) | DE3375744D1 (en) |
FR (1) | FR2533057B1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE4432532A1 (en) * | 1994-09-13 | 1996-03-14 | Stn Atlas Elektronik Gmbh | Process for the elimination of structure-borne noise |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB9023458D0 (en) * | 1990-10-29 | 1990-12-12 | Noise Cancellation Tech | Active vibration control system with multiple inputs |
GB2271909B (en) * | 1992-10-21 | 1996-05-22 | Lotus Car | Adaptive control system |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2776020A (en) * | 1955-02-09 | 1957-01-01 | Gen Electric | Noise reducing system for transformers |
US4232381A (en) * | 1979-06-08 | 1980-11-04 | Northrop Corporation | Noise cancellation using tracking filter |
JPS5717027A (en) * | 1980-07-03 | 1982-01-28 | Hitachi Ltd | Vibration reducing device of electric machinery |
-
1982
- 1982-09-09 FR FR8215280A patent/FR2533057B1/en not_active Expired
-
1983
- 1983-09-06 DE DE8383108765T patent/DE3375744D1/en not_active Expired
- 1983-09-06 EP EP83108765A patent/EP0103256B1/en not_active Expired
- 1983-09-06 AU AU18749/83A patent/AU1874983A/en not_active Abandoned
- 1983-09-09 CA CA000436328A patent/CA1208351A/en not_active Expired
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE4432532A1 (en) * | 1994-09-13 | 1996-03-14 | Stn Atlas Elektronik Gmbh | Process for the elimination of structure-borne noise |
Also Published As
Publication number | Publication date |
---|---|
FR2533057B1 (en) | 1986-05-16 |
EP0103256A1 (en) | 1984-03-21 |
AU1874983A (en) | 1984-03-15 |
DE3375744D1 (en) | 1988-03-31 |
FR2533057A1 (en) | 1984-03-16 |
CA1208351A (en) | 1986-07-22 |
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