EP0405331A2 - Acoustic sensing device with noise cancellation - Google Patents
Acoustic sensing device with noise cancellation Download PDFInfo
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- EP0405331A2 EP0405331A2 EP90111750A EP90111750A EP0405331A2 EP 0405331 A2 EP0405331 A2 EP 0405331A2 EP 90111750 A EP90111750 A EP 90111750A EP 90111750 A EP90111750 A EP 90111750A EP 0405331 A2 EP0405331 A2 EP 0405331A2
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- noise
- sensor
- source
- control circuit
- sensor device
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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
- 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
- G10K11/1783—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 handling or detecting of non-standard events or conditions, e.g. changing operating modes under specific operating conditions
- G10K11/17837—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 handling or detecting of non-standard events or conditions, e.g. changing operating modes under specific operating conditions by retaining part of the ambient acoustic environment, e.g. speech or alarm signals that the user needs to hear
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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
- G10K2210/00—Details of active noise control [ANC] covered by G10K11/178 but not provided for in any of its subgroups
- G10K2210/10—Applications
- G10K2210/108—Communication systems, e.g. where useful sound is kept and noise is cancelled
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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
- G10K2210/3013—Analogue, i.e. using analogue computers or circuits
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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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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S367/00—Communications, electrical: acoustic wave systems and devices
- Y10S367/901—Noise or unwanted signal reduction in nonseismic receiving system
Definitions
- the invention relates to acoustic sensor devices with noise suppression for detecting the useful sound emitted by an object, and in particular to sensor devices which are arranged on a noise-generating unit.
- the detection range i. H. the range for acoustic detection and location of the sensor or sensors of the device for the object sound to be measured is limited.
- Control circuits have already been used to generate compensation vibrations or antisound signals, to which the signal picked up by a sensor has been fed and which set an antisound source on the basis of this signal.
- An example of this can be found in DE-PS 30 25 391.
- the control circuit is electro-acoustically supplied with a setpoint which represents the time-fluctuating useful signal and which is superimposed on the interference signal coming from outside via the airway.
- the resulting vibration which is recorded with a microphone, is weighted using a linear filter and continuously compared with the setpoint.
- this circuit does not work if, in addition to the interference signal, the useful signal is also radiated in by air.
- the proposed regulation of the difference signal after low-pass filtering only makes an effective contribution at certain interference frequencies, in that the voltage generated at the low-pass filter is fed back with the aid of a control circuit to the amplifier of the microphone, which mainly detects noise components, and the gain is readjusted until the low-pass filtering below has dropped a predetermined value.
- this measure is only suitable for exclusively low-frequency interference sound components and only higher-frequency useful sound components, it cannot be prevented that useful signal contributions inevitably drop out in both signals when a difference is formed. Even if the microphone amplifiers are set manually, this cannot be completely prevented.
- Such a manual setting is otherwise only suitable for personal soundproofing by means of ear cups and not for a sensor device for detecting and locating object sound.
- the invention is based on the object of specifying an acoustic sensor device for detecting useful signals of an emitting object which, although arranged on or in the vicinity of a noise-generating interference source, ensures extensive attenuation of the interference noise of the interference source, but the useful sound emitted by the object if possible, no weakening is experienced and can thus be understood with an improved range.
- the sensor device distinguishes by the intended dop pelsensor, whose individual sensors positioned between the interference source and the object to be detected are directed towards the interference source or the object, already during the sound measurement between useful sound, which essentially falls from the front, and disturbing sound, which essentially falls from behind. If only one of the two sensors is used for control, direction-dependent noise suppression is possible and complex frequency-selective measures for the subsequent differentiation between object noise and noise in signal processing can be omitted.
- the interference noise suppression in the control circuit only connected to the control loop sensor can take place effectively and in terms of circuit technology. Because of the directivity of the two sensors, the object sound component in the signal supplied by the sensor is only very little attenuated by this regulation, while the interference sound component is effectively weakened by the active reduction by means of anti-sound, so that the detection range of the entire sensor device is increased.
- the sensor device enables the detection of the useful signals with a large range by effective, direction-dependent interference noise suppression by completely separating the control loop sensor and the useful or object noise sensor for noise of all possible frequencies and noise of completely unknown origin without complex frequency-selective measures.
- two anti-parallel directional microphones preferably with cardioid directional characteristics, are used as the double sensor.
- the device according to the invention is particularly suitable for sensors arranged to generate interference noises, these sensors becoming considerably less sensitive to the interference level of their own carrier aggregate.
- the sensor device according to the invention also provides improved detection ranges compared to other sources of interference which radiate interference noise essentially from a rearward direction.
- the sensors can be tuned to the same or correspondingly different frequency ranges, both with knowledge of the interference and / or useful signals as well as with completely unknown sound objects and / or interference sources, whereby the damping distance between interference and object noise ultimately present in the useful signal can be further improved.
- the anti-noise unit consisting of the anti-noise source, the control circuit and the double sensor located in the irradiation area of the anti-noise source can be pivoted as a whole, so that the optimum alignment between the interference source and the object can be adjusted.
- the schematically shown in the figure, from two anti parallel directional microphones M1 and m2 existing double sensor is arranged on a noise-generating unit, not shown, for example any device or vehicle, in such a way that it receives the interference sound p S from this interference source S from behind and picks up the object sound, ie the useful sound p N from the front .
- the microphone M1 directed towards the interference source S is connected to a control circuit R, which in turn adjusts an anti-noise source A.
- the anti-noise source A is arranged between the interference source S and the double sensor in such a way that the latter is located in the irradiation area of the anti-noise source.
- the microphone M1 included in the anti-noise system receives the interference sound p S without attenuation and the object sound p N is attenuated in accordance with the directional characteristic in accordance with the forward-back ratio of the microphone.
- the detected by the microphone M1 sound substantially to the background noise p S, the control circuit R is supplied to the anti-sound source A adjusts by means of this sound signal, that these necessary for the compensation of p S antinoise p generated A.
- the control circuit R which regulates the noise signal supplied to it under control of the anti-noise source, consists of filter networks and amplifiers which are dimensioned such that the control circuit remains stable in the intended frequency range.
- the directed away for réelleméden object and away from the noise source S microphone 2 performs the actual sensor task and receives attenuated the object to be detected sound unattenuated N p and the interference noise S p e loom the directivity.
- the relationship (1) shows that due to the forward-back ratio r of the microphones, the control loop penetration to p N and p S is different, so that in the desired manner the object sound p N is reduced only slightly, while the background noise p S is greatly reduced.
- the advance detection range of the acoustic sensor device is thus increased by actively reducing the noise coming from behind by means of anti-noise.
- the acoustic sensor device is thus less sensitive to the interference level of its own carrier unit.
- the anti-parallel pair of directional microphones M1, M2 has microphones each with a cardioid directional characteristic.
- lobe-like directional characteristics are also possible, and different characteristics can also be selected for the two sensors in order to achieve an optimal alignment with the object sound field and the noise.
- the same also applies to the frequency ranges of the inward and outward-facing sensors, which can preferably be tuned in frequency independently of one another.
- the unit schematically shown in the figure consisting of a double sensor, control circuit and anti-noise source, is preferably pivotally installed overall in order to enable adjustment to different directions of incidence.
Abstract
Akustische Sensoreinrichtung mit Störschallunterdrückung insbesondere für auf einem geräuscherzeugenden Aggregat angeordnete Sensoren unter Verwendung eines Doppelsensors (M1,M2), der zwischen einer Störquelle (S) und einem den aufzufassenden Objektschall aussendenden Objekt angeordnet ist und dessen einer Sensor (M1) auf die Störquelle (S) gerichtet ist und einer Regelschaltung (R) ein Störschallsignal zuführt, welche eine Antischallquelle (A) so einstellt, daß diese einen Antischall pA zur Kompensation des Störschalls pS erzeugt, wobei der andere Sensor (M2) auf das aufzufassende Objekt gerichtet ist und ein Meßsignal liefert, in dem der Störschallanteil stark und der Objektschallanteil sehr wenig geschwächt sind, so daß durch diese Minderung der Schallanteile in Anhängigkeit von der Einfallsrichtung die Auffaßreichweite des Sensors (M2) vergrößert ist. <IMAGE>Acoustic sensor device with noise suppression, in particular for sensors arranged on a noise-generating unit, using a double sensor (M1, M2), which is arranged between an interference source (S) and an object that emits the object sound to be detected, and whose one sensor (M1) points to the interference source (S ) is directed and a control circuit (R) feeds a noise signal, which adjusts an anti-noise source (A) so that it generates an anti-noise pA to compensate for the noise pS, the other sensor (M2) being directed to the object to be detected and a measurement signal delivers, in which the noise component is strong and the object noise component is weakened very little, so that the detection range of the sensor (M2) is increased by this reduction in the sound components depending on the direction of incidence. <IMAGE>
Description
Die Erfindung betrifft akustische Sensoreinrichtungen mit Störschallunterdrückung zum Erfassen des von einem Objekt ausgesendeten Nutzschalls und insbesondere Sensoreinrichtungen, die auf einem geräuscherzeugenden Aggregat angeordnet sind. Infolge des vom Trägeraggregat der Sensoreinrichtung am Sensorort erzeugten Störpegels ist die Auffaßreichweite, d. h. die Reichweite zur akustischen Entdeckung und Ortung des oder der Sensoren der Einrichtung für den jeweils zu messenden Objektschall begrenzt.The invention relates to acoustic sensor devices with noise suppression for detecting the useful sound emitted by an object, and in particular to sensor devices which are arranged on a noise-generating unit. As a result of the interference level generated by the carrier unit of the sensor device at the sensor location, the detection range, i. H. the range for acoustic detection and location of the sensor or sensors of the device for the object sound to be measured is limited.
Passive Unterdrückungsmaßnahmen für den Störschall haben naturgemäß den Nachteil, daß neben dem Störschall auch der von einem Objekt kommende, aufzufassende Nutzschall geschwächt wird. Auch die in der Literatur beschriebenen aktiven Antischallsysteme, die zur Geräuschminderung in der Umgebung eines Aufpunktes das dort vorliegende Schallfeld, gleich welcher Herkunft, insgesamt durch Überlagerung eines gegenphasigen Schallfeldes schwächen oder sogar kompensieren, vermindern in nachteiliger Weise sowohl Störals auch Nutzschall, da Objektschall und Störquellenschall antischallmäßig gleich behandelt werden. Selbst wenn man entweder von der Störquelle oder vom den Nutzschall aussendenden Objekt über soviel Information verfügt, daß man durch frequenzselektive Maßnahmen, z.B. den Einsatz adaptiver Digitalfilter, oder Synchronisationsmaßnahmen zwischen Nutz- und Störschallsignalen unterscheiden kann, kann zwar eine gezieltere Schwächung des Störschalls gelingen, eine entsprechende Schwächung des Nutzsignals durch den Antischall läßt sich jedoch auch dann nicht verhindern.Passive suppression measures for background noise naturally have the disadvantage that, in addition to the background noise, the useful noise coming from an object is also weakened. The active anti-noise systems described in the literature, which, in order to reduce noise in the vicinity of a point of attack, weaken or even compensate the sound field there, regardless of its origin, by superimposing an anti-phase sound field, disadvantageously reduce both interference and useful noise, since object noise and interference source noise are treated equally in terms of antisound. Even if one has enough information either from the interference source or from the object emitting the useful sound that one can distinguish between useful and interference signals by frequency-selective measures, for example the use of adaptive digital filters, or synchronization measures A more targeted weakening of the noise is possible, but a corresponding weakening of the useful signal by the anti-noise cannot be prevented even then.
Bei der Erzeugung von Kompensationsschwingungen bzw. Antischallsignalen wurden bereits Regelschaltungen verwendet, denen das von einem Sensor aufgenommene Signal zugeführt wurde und die eine Antischallquelle aufgrund dieses Signals einstellten. Ein Beispiel hierfür findet sich in der DE-PS 30 25 391. In der dort beschriebenen Vorrichtung wird der Regelschaltung elektro-akustisch ein Sollwert zugeführt, der das zeitlich schwankende Nutzsignal darstellt und dem sich das über den Luftweg von außen kommende Störsignal überlagert. Die resultierende Schwingung, die mit einem Mikrofon aufgenommen wird, wird mittels eines linearen Filters gewichtet und fortlaufend mit dem Sollwert verglichen. Bei geeigneter Frequenzauslegung des Rückkopplungszweiges und der Nutzsignalübertragung gelingt eine Minderung der störenden Schwingung und eine mehr oder weniger befriedigende Erhaltung des Nutzsignals im resultierenden Signal. Diese Schaltung arbeitet aber nicht, wenn neben dem Störsignal auch das Nutzsignal auf dem Luftweg eingestrahlt wird.Control circuits have already been used to generate compensation vibrations or antisound signals, to which the signal picked up by a sensor has been fed and which set an antisound source on the basis of this signal. An example of this can be found in DE-PS 30 25 391. In the device described there, the control circuit is electro-acoustically supplied with a setpoint which represents the time-fluctuating useful signal and which is superimposed on the interference signal coming from outside via the airway. The resulting vibration, which is recorded with a microphone, is weighted using a linear filter and continuously compared with the setpoint. With a suitable frequency design of the feedback branch and the useful signal transmission, the disturbing oscillation is reduced and the useful signal is more or less satisfactorily preserved in the resulting signal. However, this circuit does not work if, in addition to the interference signal, the useful signal is also radiated in by air.
Auch die DE 31 33 107 A1 löst die obigen Probleme nicht. Im dort vorgeschlagenen Personenschallschutz sind zwei Mikrophone mit unterschiedlicher Richtcharakteristik zu einer Seite ausgerichtet. Wegen der unterschiedlichen Richtcharakteristik unterscheiden sich Stör- und Nutzsignalbeiträge in den von den Mikrophonen gelieferten elektrischen Signalen, wenn Stör- und Nutzschall aus unterschiedlichen Richtungen einfallen. Beide Signale werden auf einen Differenzverstärker gegeben, dessen Ausgangssignal einem Endverstärker zugeführt wird und das erfaßte und selektierte Nutzsignal darstellt, das in eine Ohrmuschel eingespeist wird. Eine wirksame Unterdrückung des Störschalls bei möglichst weitestge hender Erhaltung des Nutzsignalanteils ist letztlich nur mit Hilfe manueller unterschiedlicher Einstellung der beiden Mikrophonverstärker möglich.DE 31 33 107 A1 does not solve the above problems either. In the personal noise protection proposed there, two microphones with different directional characteristics are oriented to one side. Because of the different directional characteristics, interference and useful signal contributions differ in the electrical signals supplied by the microphones when interference and useful sound come from different directions. Both signals are fed to a differential amplifier, the output signal of which is fed to a power amplifier and represents the detected and selected useful signal which is fed into an ear cup. An effective suppression of noise at the greatest possible Maintaining the useful signal component is ultimately only possible with the help of different manual settings of the two microphone amplifiers.
Die vorgeschlagene Regelung des Differenzsignals nach Tiefpassfilterung liefert nur bei bestimmten Störfrequenzen einen wirkungsvollen Beitrag, indem die am Tiefpaßfilter entstehende Spannung mit Hilfe einer Regelschaltung zum Verstärker des Mikrophons zurückgeführt wird, das hauptsächlich Störschallanteile erfaßt, und die Verstärkung so lange nachgeregelt wird, bis die Tiefpaßfilterung unter einen vorbestimmten Wert abgesunken ist. Abgesehen davon, daß diese Maßnahme nur für ausschließlich tieffrequente Störschallanteile und ausschließlich höherfrequente Nutzschallanteile geeignet ist, kann nicht verhindert werden, daß bei Differenzbildung unvermeidlicherweise in beiden Signalen vorhandene Nutzsignalbeiträge herausfallen. Selbst wenn die Mikrofonverstärker manuell eingestellt werden, kann dies nicht völlig unterbunden werden.The proposed regulation of the difference signal after low-pass filtering only makes an effective contribution at certain interference frequencies, in that the voltage generated at the low-pass filter is fed back with the aid of a control circuit to the amplifier of the microphone, which mainly detects noise components, and the gain is readjusted until the low-pass filtering below has dropped a predetermined value. Apart from the fact that this measure is only suitable for exclusively low-frequency interference sound components and only higher-frequency useful sound components, it cannot be prevented that useful signal contributions inevitably drop out in both signals when a difference is formed. Even if the microphone amplifiers are set manually, this cannot be completely prevented.
Eine solche manuelle Einstellung eignet sich im übrigen nur für den persönlichen Schallschutz mittels Ohrmuscheln und nicht für eine Sensoreinrichtung zur Erfassung und Ortung von Objektschall.Such a manual setting is otherwise only suitable for personal soundproofing by means of ear cups and not for a sensor device for detecting and locating object sound.
Der Erfindung liegt die Aufgabe zugrunde, eine akustische Sensoreinrichtung zur Erfassung von Nutzsignalen eines aussendenden Objekts anzugeben, die, obwohl sie auf oder in der Nähe einer geräuscherzeugenden Störquelle angeordnet ist, eine weitgehende Schwachung des Störschalls der Störquelle gewährleistet, wobei der vom Objekt ausgesendete Nutzschall aber möglichst keine Schwächung erfährt und so mit verbesserter Reichweite aufgefaßt werden kann.The invention is based on the object of specifying an acoustic sensor device for detecting useful signals of an emitting object which, although arranged on or in the vicinity of a noise-generating interference source, ensures extensive attenuation of the interference noise of the interference source, but the useful sound emitted by the object if possible, no weakening is experienced and can thus be understood with an improved range.
Diese Aufgabe wird durch den Gegenstand des Patentanspruchs 1 gelöst.This object is achieved by the subject matter of patent claim 1.
Die erfindungsgemäße Sensoreinrichtung unterscheidet im Gegensatz zum Stand der Technik durch den vorgesehenen Dop pelsensor, dessen zwischen Störquelle und aufzufassendem Objekt positionierte Einzelsensoren auf die Störquelle bzw. das Objekt gerichtet sind, bereits bei der Schallmessung zwischen Nutzschall, der im wesentlichen von vorn einfällt, und Störschall, der im wesentlichen von hinten einfällt. Benutzt man nur einen der beiden Sensoren zur Regelung, ist eine richtungsabhängige Störschallunterdrückung möglich und aufwendige frequenzselektive Maßnahmen zur nachträglichen Differenzierung zwischen Objektschall und Störschall in der Signalverarbeitung können entfallen.In contrast to the prior art, the sensor device according to the invention distinguishes by the intended dop pelsensor, whose individual sensors positioned between the interference source and the object to be detected are directed towards the interference source or the object, already during the sound measurement between useful sound, which essentially falls from the front, and disturbing sound, which essentially falls from behind. If only one of the two sensors is used for control, direction-dependent noise suppression is possible and complex frequency-selective measures for the subsequent differentiation between object noise and noise in signal processing can be omitted.
Da die Aufgaben der Antischallregelung und der Nutzschallauffassung erfindungsgemäß auf einen Regelkreis- und einen Auffaßsensor aufgeteilt sind, kann die Störschallunterdrükkung in der nur mit dem Regelkreissensor verbundenen Regelschaltung effektiv und schaltungstechnisch einfach erfolgen. Wegen der Richtwirkung der beiden Sensoren wird durch diese Regelung der Objektschallanteil im vom Auffaßsensor gelieferten Signal nur äußerst wenig, der Störschallanteil dagegen durch die aktive Minderung mittels Antischall wirksam geschwächt, so daß die Auffaßreichweite der gesamten Sensoreinrichtung vergrößert ist.Since the tasks of the anti-noise control and the useful sound perception are divided according to the invention into a control loop sensor and a detection sensor, the interference noise suppression in the control circuit only connected to the control loop sensor can take place effectively and in terms of circuit technology. Because of the directivity of the two sensors, the object sound component in the signal supplied by the sensor is only very little attenuated by this regulation, while the interference sound component is effectively weakened by the active reduction by means of anti-sound, so that the detection range of the entire sensor device is increased.
Im Gegensatz zu den Entgegenhaltungen ermöglicht die erfindungsgemäße Sensoreinrichtung durch die völlige Trennung von Regelkreissensor und Nutz- bzw. Objektschallsensor für Störschall aller möglichen Frequenzen und Nutzschall auch gänzlich unbekannter Herkunft ohne aufwendige frequenzselektive Maßnahmen die Erfassung der Nutzsignale mit großer Reichweite durch eine effektive, richtungsabhängige Störschallunterdrückung.In contrast to the references, the sensor device according to the invention enables the detection of the useful signals with a large range by effective, direction-dependent interference noise suppression by completely separating the control loop sensor and the useful or object noise sensor for noise of all possible frequencies and noise of completely unknown origin without complex frequency-selective measures.
In der einfachsten Ausführung werden als Doppelsensor zwei antiparallele Richtmikrofone vorzugsweise mit nierenförmiger Richtcharakteristik benutzt. Es ist jedoch auch möglich, z.B. den Auffaßsensor nicht exakt nach vorn auszurichten und andere, speziell für das Schallfeld vom Objekt ausgelegte Richtcharakteristiken zu verwenden. Dies gilt auch für den die Störquelle erfassenden Regelkreissensor.In the simplest version, two anti-parallel directional microphones, preferably with cardioid directional characteristics, are used as the double sensor. However, it is also possible, for example, not to align the detection sensor exactly to the front and others, especially for the sound field from the object directional characteristics designed to use. This also applies to the control loop sensor that detects the source of the interference.
Die erfindungsgemäße Einrichtung eignet sich in besonderer Weise für auf Störgeräusche erzeugenden Trägeraggregaten angeordnete Sensoren, wobei diese erheblich unempfindlicher gegenüber dem Störpegel ihres eigenen Trägeraggregats werden. Jedoch erbringt die erfindungsgemäße Sensoreinrichtung auch verbesserte Auffaßreichweiten gegenüber anderen Störquellen, die Störschall im wesentlichen aus einer rückwärtigen Richtung einstrahlen.The device according to the invention is particularly suitable for sensors arranged to generate interference noises, these sensors becoming considerably less sensitive to the interference level of their own carrier aggregate. However, the sensor device according to the invention also provides improved detection ranges compared to other sources of interference which radiate interference noise essentially from a rearward direction.
Weiterhin können sowohl bei Kenntnis der Stör- und/oder Nutzsignale als auch bei völlig unbekannten Schallobjekten und/oder Störquellen die Sensoren auf gleiche oder entsprechend unterschiedliche Frequenzbereiche abstimmbar sein, wobei der letztlich im Nutzsignal vorhandene Dämpfungsabstand zwischen Stör- und Objektschall noch verbessert werden kann.Furthermore, the sensors can be tuned to the same or correspondingly different frequency ranges, both with knowledge of the interference and / or useful signals as well as with completely unknown sound objects and / or interference sources, whereby the damping distance between interference and object noise ultimately present in the useful signal can be further improved.
Ferner ist es von Vorteil, wenn die aus Antischallquelle, Regelschaltung und dem im Einstrahlbereich der Antischallquelle liegenden Doppelsensor bestehende Antischalleinheit insgesamt schwenkbar ist, so daß die jeweils optimale Ausrichtung zwischen Störquelle und Objekt einstellbar ist.Furthermore, it is advantageous if the anti-noise unit consisting of the anti-noise source, the control circuit and the double sensor located in the irradiation area of the anti-noise source can be pivoted as a whole, so that the optimum alignment between the interference source and the object can be adjusted.
Es können auch verschiedene richtungs- und in Bezug auf die Sensoren frequenzselektive derartige Einheiten kombiniert werden, die ein umfassendes Ergebnis verschiedenster aufzufassender Objekte und Störquellen liefern.It is also possible to combine different directional and frequency-selective units with respect to the sensors, which deliver a comprehensive result of the most varied objects and sources of interference to be understood.
Im folgenden wird die Erfindung anhand der Zeichnung näher erläutert, wobei diese ein Ausführungsbeispiel der erfindungsgemäßen akustischen Sensoreinrichtung zeigt.The invention is explained in more detail below with reference to the drawing, which shows an embodiment of the acoustic sensor device according to the invention.
Der in der Figur schematisch dargestellte, aus zwei anti parallelen Richtmikrofonen M1 und m2 bestehende Doppelsensor ist auf einem nicht näher dargestellten geräuscherzeugenden Aggregat, z.B. irgendeinem Gerät oder Fahrzeug, so angeordnet, daß er den Störschall pS von dieser Störquelle S von hinten empfängt und den Objektschall, d.h. den Nutzschall pN von vorn aufnimmt.The schematically shown in the figure, from two anti parallel directional microphones M1 and m2 existing double sensor is arranged on a noise-generating unit, not shown, for example any device or vehicle, in such a way that it receives the interference sound p S from this interference source S from behind and picks up the object sound, ie the useful sound p N from the front .
Das zur Störquelle S hin gerichtete Mikrofon M1 ist an eine Regelschaltung R angeschlossen, die wiederum eine Antischallquelle A einstellt. Die Antischallquelle A ist so zwischen der Störquelle S und dem Doppelsensor angeordnet, daß letzterer im Einstrahlbereich der Antischallquelle liegt.The microphone M1 directed towards the interference source S is connected to a control circuit R, which in turn adjusts an anti-noise source A. The anti-noise source A is arranged between the interference source S and the double sensor in such a way that the latter is located in the irradiation area of the anti-noise source.
Das in das Antischallsystem einbezogene Mikrofon M1 empfängt den Störschall pS ungeschwächt und den Objektschall pN infolge der Richtcharakteristik dem Vor-Rück-Verhältnis des Mikrofons entsprechend abgeschwächt. Der vom Mikrofon M1 festgestellte Schall, im wesentlichen der Störschall pS, wird der Regelschaltung R zugeführt, die mit Hilfe dieses Schallsignals die Antischallquelle A so einstellt, daß diese den zur Kompensation von pS notwendigen Antischall pA erzeugt.The microphone M1 included in the anti-noise system receives the interference sound p S without attenuation and the object sound p N is attenuated in accordance with the directional characteristic in accordance with the forward-back ratio of the microphone. The detected by the microphone M1 sound substantially to the background noise p S, the control circuit R is supplied to the anti-sound source A adjusts by means of this sound signal, that these necessary for the compensation of p S antinoise p generated A.
Die Regelschaltung R, die das ihr zugeführte Störschallsignal unter Ansteuerung der Antischallquelle auf Null regelt, besteht aus Filternetzwerken und Verstärkern, die so bemessen sind, daß der Regelkreis im vorgesehenen Frequenzbereich stabil bleibt.The control circuit R, which regulates the noise signal supplied to it under control of the anti-noise source, consists of filter networks and amplifiers which are dimensioned such that the control circuit remains stable in the intended frequency range.
Das zum aufzufassenden Objekt hin und von der Störquelle S weg gerichtete Mikrofon 2 übernimmt die eigentliche Sensoraufgabe und empfängt den zu erfassenden Objektschall pN ungeschwächt und den Störschall pS entsprechend der Richtwirkung abgeschwächt.The directed away for aufzufassenden object and away from the noise source S microphone 2 performs the actual sensor task and receives attenuated the object to be detected sound unattenuated N p and the interference noise S p e ntsprechend the directivity.
Die Analyse des Regelkreises aus dem Mikrofon M1, der Regelschaltung R und der Antischallquelle A liefert für das von M2 gemessene Sensorsignal U die folgende Beziehung:
U ∼ pN(1-H/r²) + pS(1-H)/r , (1)
in der H die Open-Loop-Verstärkung des Regelkreises ist und r das wie in der Antennentechnik definierte Vor-Rück-Verhältnis beider Richtmikrofone angibt.The analysis of the control loop from the microphone M1, the control circuit R and the anti-noise source A provides the following relationship for the sensor signal U measured by M2:
U ∼ p N (1-H / r²) + p S (1-H) / r, (1)
where H is the open loop gain of the control loop and r is the forward-back ratio of the two directional microphones as defined in antenna technology.
Die Beziehung (1) zeigt, daß aufgrund des Vor-Rück-Verhältnisses r der Mikrofone der Regelkreisdurchgriff auf pN und pS unterschiedlich ausfällt, so daß in gewünschter Weise der Objektschall pN nur wenig, der Störschall pS dagegen stark gemindert wird.The relationship (1) shows that due to the forward-back ratio r of the microphones, the control loop penetration to p N and p S is different, so that in the desired manner the object sound p N is reduced only slightly, while the background noise p S is greatly reduced.
Es erfolgt demnach die Minderung der Schallanteile am Aufpunkt in Abhängigkeit von deren Einfallsrichtung. Damit ist die Voraus-Auffaßreichweite der akustischen Sensoreinrichtung durch eine aktive Minderung des von hinten kommenden Störschalls mittels Antischall vergrößert. Die akustische Sensoreinrichtung wird somit unempfindlicher gegen den Störpegel ihres eigenen Trägeraggregats.Accordingly, the sound components at the point of impact are reduced depending on their direction of incidence. The advance detection range of the acoustic sensor device is thus increased by actively reducing the noise coming from behind by means of anti-noise. The acoustic sensor device is thus less sensitive to the interference level of its own carrier unit.
Das antiparallele Paar von Richtmikrofonen M1, M2 weist im Ausführungsbeispiel Mikrofone mit jeweils nierenförmiger Richtcharakteristik auf. Es sind jedoch auch keulenartige Richtcharakteristiken möglich, wobei auch unterschiedliche Charakteristiken für die beiden Sensoren gewählt werden können, um eine jeweils optimale Ausrichtung auf das Objektschallfeld und den Störschall zu erzielen. Das gleiche gilt auch für die Frequenzbereiche der einwärts und auswärts gerichteten Sensoren, die vorzugsweise unabhängig voneinander frequenzmäßig abstimmbar sind.In the exemplary embodiment, the anti-parallel pair of directional microphones M1, M2 has microphones each with a cardioid directional characteristic. However, lobe-like directional characteristics are also possible, and different characteristics can also be selected for the two sensors in order to achieve an optimal alignment with the object sound field and the noise. The same also applies to the frequency ranges of the inward and outward-facing sensors, which can preferably be tuned in frequency independently of one another.
Die in der Figur schematisch dargestellte Einheit aus Doppelsensor, Regelschaltung und Antischallquelle ist vorzugsweise insgesamt schwenkbar installiert, um die Einstellung auf verschiedene Einfallsrichtungen zu ermöglichen.The unit schematically shown in the figure, consisting of a double sensor, control circuit and anti-noise source, is preferably pivotally installed overall in order to enable adjustment to different directions of incidence.
Werden verschiedene richtungs- und/oder frequenzselektive Einrichtungen der beschriebenen Art miteinander kombiniert, so kann die universelle Verwendbarkeit der erfindungsgemäßen Sensoreinrichtung für die unterschiedlichsten Aufgaben und Schallbedingungen noch weiter verbessert werden.If different directional and / or frequency-selective devices of the type described are combined with one another, the universal usability of the sensor device according to the invention for the most varied of tasks and sound conditions can be further improved.
Claims (7)
dadurch gekennzeichnet,
daß der Doppelsensor als antiparalleles Paar von Richtmikrofonen (M1, M2) ausgebildet ist, von denen das eine (M2) auswärts auf das Objekt hin gerichtet ist und das andere, an die Regelschaltung (R) angeschlossene Mikrofon (M1) einwärts auf die Störquelle (S) und die davor angeordnete Antischallquelle (A) gerichtet ist.2. Acoustic sensor device according to claim 1,
characterized,
that the double sensor is designed as an anti-parallel pair of directional microphones (M1, M2), of which one (M2) is directed outwards towards the object and that Another microphone (M1) connected to the control circuit (R) is directed inwards towards the interference source (S) and the antisound source (A) arranged in front of it.
dadurch gekennzeichnet,
daß die Richtmikrofone eine nierenförmige Richtcharakteristik aufweisen.3. Acoustic sensor device according to claim 2.
characterized,
that the directional microphones have a cardioid polar pattern.
dadurch gekennzeichnet,
daß die beiden Sensoren des Doppelsensors wahlweise gleiche oder verschiedene Richtcharakteristiken aufweisen.4. Acoustic sensor device according to one of claims 1 and 2,
characterized,
that the two sensors of the double sensor optionally have the same or different directional characteristics.
dadurch gekennzeichnet,
daß die beiden Sensoren des Doppelsensors wahlweise auf gleiche oder verschiedene Frequenzbereiche abstimmbar sind.5. Acoustic sensor device according to one of the preceding claims,
characterized,
that the two sensors of the double sensor can optionally be tuned to the same or different frequency ranges.
dadurch gekennzeichnet,
daß die aus dem Doppelsensor (M1, M2), der Regelschaltung (R) und der Antischallquelle (A) bestehende Einrichtung als schwenkbare Einheit ausgebildet ist.6. Acoustic sensor device according to one of the preceding claims,
characterized,
that the device consisting of the double sensor (M1, M2), the control circuit (R) and the anti-noise source (A) is designed as a pivotable unit.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE3921307A DE3921307A1 (en) | 1989-06-29 | 1989-06-29 | ACOUSTIC SENSOR DEVICE WITH SOUND CANCELLATION |
| DE3921307 | 1989-06-29 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0405331A2 true EP0405331A2 (en) | 1991-01-02 |
| EP0405331A3 EP0405331A3 (en) | 1992-02-26 |
Family
ID=6383862
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP19900111750 Withdrawn EP0405331A3 (en) | 1989-06-29 | 1990-06-21 | Acoustic sensing device with noise cancellation |
Country Status (4)
| Country | Link |
|---|---|
| US (1) | US5040156A (en) |
| EP (1) | EP0405331A3 (en) |
| JP (1) | JPH0351782A (en) |
| DE (1) | DE3921307A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1994002935A1 (en) * | 1992-07-22 | 1994-02-03 | Sinvent A/S | Method and device for active noise reduction in a local area |
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| DE9409320U1 (en) * | 1994-06-08 | 1995-07-06 | Berlin Florence | Respirator and microphone holder for use therein |
| USRE39412E1 (en) * | 1995-02-15 | 2006-11-28 | Matsushita Electric Industrial Co., Ltd. | Optical information medium, and method and apparatus for fabricating the same |
| US5681634A (en) * | 1995-02-15 | 1997-10-28 | Matsushita Electric Industrial Co., Ltd. | Optical information medium, and method and apparatus for fabricating the same |
| FR2741182B1 (en) * | 1995-11-13 | 1998-01-02 | Technofirst | METHOD AND DEVICE FOR EXTRACTING A USEFUL ACOUSTIC SIGNAL FROM A COMPOSITE ACOUSTIC SIGNAL COMPRISING INTERFERRED COMPONENTS |
| US6987856B1 (en) | 1996-06-19 | 2006-01-17 | Board Of Trustees Of The University Of Illinois | Binaural signal processing techniques |
| US6978159B2 (en) * | 1996-06-19 | 2005-12-20 | Board Of Trustees Of The University Of Illinois | Binaural signal processing using multiple acoustic sensors and digital filtering |
| DK1312239T3 (en) * | 2000-05-10 | 2007-04-30 | Univ Illinois | Techniques for suppressing interference |
| US6492937B1 (en) | 2001-11-02 | 2002-12-10 | Itt Manufacturing Enterprises, Inc. | High precision range measurement technique |
| US7512448B2 (en) | 2003-01-10 | 2009-03-31 | Phonak Ag | Electrode placement for wireless intrabody communication between components of a hearing system |
| US7945064B2 (en) * | 2003-04-09 | 2011-05-17 | Board Of Trustees Of The University Of Illinois | Intrabody communication with ultrasound |
| US7076072B2 (en) * | 2003-04-09 | 2006-07-11 | Board Of Trustees For The University Of Illinois | Systems and methods for interference-suppression with directional sensing patterns |
| DE102006023735A1 (en) * | 2006-05-19 | 2007-12-06 | Siemens Audiologische Technik Gmbh | Measuring box for a hearing device and corresponding measuring method |
| DE202011052130U1 (en) * | 2011-11-28 | 2012-12-05 | Sato Schneidsysteme Anton Hubert E.K. | plasma torch |
| DE202014008783U1 (en) | 2014-11-05 | 2014-12-12 | Gunter Henkel | Sleep hood - Device for reducing or eliminating snoring and sleeping sounds |
| DE102014016397A1 (en) | 2014-11-05 | 2016-05-12 | Gunter Henkel | Sleep hood: Device for reducing or eliminating snoring and sleeping sounds |
| JP6811954B2 (en) * | 2016-07-20 | 2021-01-13 | 株式会社オーディオテクニカ | Microphone |
| JP2022077684A (en) | 2020-11-12 | 2022-05-24 | 株式会社東芝 | Acoustic inspection apparatus and acoustic inspection method |
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| DE3025391A1 (en) * | 1980-07-04 | 1982-01-28 | Battelle-Institut E.V., 6000 Frankfurt | Process control loop with suppression of acoustic vibration - uses compensation by comparing with reference valve and superimposing error in antiphase |
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- 1989-06-29 DE DE3921307A patent/DE3921307A1/en active Granted
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- 1990-06-21 EP EP19900111750 patent/EP0405331A3/en not_active Withdrawn
- 1990-06-29 JP JP2172553A patent/JPH0351782A/en active Pending
- 1990-06-29 US US07/545,531 patent/US5040156A/en not_active Expired - Fee Related
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| DE3133107A1 (en) * | 1981-08-21 | 1983-03-10 | Michael 5440 Mayen Hofmann | Personal sound protection |
| DE3821939A1 (en) * | 1987-06-30 | 1989-01-12 | Bridgestone Corp | Sound-deadening (sound-absorbing) device |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1994002935A1 (en) * | 1992-07-22 | 1994-02-03 | Sinvent A/S | Method and device for active noise reduction in a local area |
| US5559893A (en) * | 1992-07-22 | 1996-09-24 | Sinvent A/S | Method and device for active noise reduction in a local area |
Also Published As
| Publication number | Publication date |
|---|---|
| DE3921307A1 (en) | 1991-01-10 |
| DE3921307C2 (en) | 1992-02-13 |
| US5040156A (en) | 1991-08-13 |
| EP0405331A3 (en) | 1992-02-26 |
| JPH0351782A (en) | 1991-03-06 |
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