`
`Europ4lsches
`Patentamt
`European
`Patent Office
`Serbrewer
`
`EUROPEAN PATENT SPECIFICATION
`
`(11)
`
`EP 1 575 250 B1
`
`Date of publication and mention
`of the grant of the patent:
`17.08.2011 Bulletin 2011/33
`
`(21)
`
`Application number: 05251339.7
`
`(22)
`
`Date offiling: 07.03.2005
`
`(51) Int CL:
`HO4M 1/60 (2996.01)
`
`HO4M 9/08 (2096.01)
`
`(54)
`
`Method and apparatus for optimizing speakerphone performance based on tilt angle
`
`Verfahren und Gerat zur Optimierung der Lautsprecherleistung auf der Basis des Neigungswinkels
`
`Procédé et appareil d’optimisation du rendement d’un haut-parleur en fonction d’un angle d’inclinaison
`
`Designated Contracting States:
`DE FR GB
`
`Priority: 10.03.2004 GB 0405341
`
`Date of publication of application:
`14.09.2005 Bulletin 2005/37
`
`¢ Moquin, Phillipe
`Ottawa,
`Ontario K2K 2H6 (CA)
`
`(74) Representative: Naismith, Robert Stewart etal
`Marks & Clerk LLP
`Aurora
`120 Bothwell Street
`
`Proprietor: Mitel Networks Corporation
`Ottawa, ON K2K 2W7(CA)
`
`Glasgow
`G2 7JS (GB)
`
`Inventors:
`Dedieu, Stephane
`Ottawa,
`Ontario K2B 6Y8 (CA)
`
`(56) Referencescited:
`EP-A- 0 796 026
`GB-A- 2 344 500
`US-A1- 2002 041679
`
`DE-A1- 3 149 061
`US-A- 4 885 773
`US-B1- 6411 828
`
`EP1575250B1
`
`
`
`Note: Within nine months of the publication of the mention of the grant of the European patent in the European Patent
`Bulletin, any person may give notice to the European Patent Office of opposition to that patent, in accordance with the
`Implementing Regulations. Notice of opposition shall not be deemed to have been filed until the opposition fee has been
`paid. (Art. 99(1) European Patent Convention).
`
`Printed by Jouve, 75001 PARIS (FR)
`
`Luxottica Ex. 1029
`IPR Petition USP 10,613,355
`
`

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`EP 1 575 250 B1
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`Description
`
`Field of the Invention
`
`[0001] The invention relates generally to speaker-
`phones, and more particularly to the use ofa tilt sensor
`for detecting tilt angle of a speakerphone and in response
`improve performance characteristics.
`
`Background ofthe Invention
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`[0002] Telephones are now commonly provided with
`an adjustable stand to permit the user to adjust thetilt
`angle to a preferred viewing angle for reading the phone
`display (e.g. LCD display) as disclosed in document US
`6,122,370. This is beneficial from a visual perspective,
`but does not take into account the audio performance of
`[0007] Various aspectsof the presentinvention are de-
`the speakerphone. Typically, acoustical designers have
`fined in the independentclaims. Somepreferred features
`relied on establishing an acceptable compromise be-
`are defined in the dependent claims.
`tween visual and audio considerations in selecting an
`[0008] Described herein a method is disclosed for ad-
`industrial design for a set, or have tried to use adaptive
`filters to address audio performanceissues. In the first
`justing the performance of a speakerphone based on the
`tilt angle of the set. Unlike the prior art, the actual loud-
`case, only acompromise can be achieved. In the second
`ness of the receive level is not significantly affected by
`case, adaptivefilters are not always capable of obtaining
`the tilt angle of the telephone However, other aspects of
`enough information to provide the ideal correction to the
`acoustical performance are adjusted to compensate for
`audio signal. Moreover, adaptive filters have only been
`tilt angle. For example, the frequency response may be
`applied to the transmit signal of the set thus leaving the
`affected bytilt angle since tilt results in more or fewer
`designer with only a compromise solution for optimizing
`reflections off of a desk, and the speaker grill can have
`the receive signal to the user.
`directional effects. In a speakerphone, the microphone
`[0003]
`Tilt sensors are known in the art of portable tel-
`ephones to determine in which mode to operate a tele-
`responseis generally also affected by the angle the set
`makes with the desk. In a full-duplex speakerphone an
`phone. Colonna et al, in US Patent 6,115,620, disclose
`adaptive filter is used to reduce the receive to transmit
`a mechanical switch that determines the position of the
`two parts of a portable telephone and basedon this in-
`signal, and this coupling path is strongly affected by the
`formation permits a louder level of receive operation of
`angle the set makes with the desk. Finally, when micro-
`the set. Lands and Banh, in US Patent 6,411,828, dis-
`phone or loudspeaker arrays are embedded in a tele-
`phone, the tilt angle greatly affects their behaviour since
`close the use of a gravitational sensor to perform the
`same function. Kielsnia, in US Patent 6,449,363, disclos-
`they are very sensitive to the diffraction effects afforded
`by the set.
`es a safety mechanism based ona tilt sensor that pre-
`40
`
`vents a portable telephone from entering the speaker- [0009]Atilt sensor may be used to determine the tilt
`phone mode (i.e. louder receive signal) when the setis
`angle and this information is used to optimize both the
`at an angle that would correspond to a user placing the
`receive and transmit signals for the chosen tilt angle. The
`set in handset mode. Martschink and Pai, in US Patent
`information can also be used to adjust performance of
`6,510,326, disclose a tilt sensor that permits selecting
`any beamformer(s) where the speakerphone incorpo-
`the operational mode of a portable telephone dependant
`rates a microphone array. Vibrational data may be pro-
`on its relation to an independent reference system (i.e.
`vided by the tilt sensor for enhancing the receive signal
`and acoustic echo cancellation.
`gravity). Martschink and Pai specifically set forth a tele-
`phone that switches between quiet and loud operation
`(i.e. substantially the same as handset and speaker-
`phone modes) where, in the quiet (i.e. handset) mode,
`only the user can understand the receive signal. All of
`foregoing prior art relates to handheld telephones where
`only the receive volumeis adjusted.
`[0004] An example of a speakerphone system is de-
`[0011] The choice of sensor depends on the amount
`scribed by US6411828, which describes a wireless user
`of information required and the specific implementation.
`terminal that operates in a mode that is selected based
`on an indication of the orientation of the wireless user
`Of the three sensors discussed above, the mostinforma-
`terminal. When the wireless user terminal is inafirst ori-
`tion is provided by the accelerometer. However,it is also
`
`entation, the wireless user terminal operates in a speak-
`erphone modeand when the wireless user terminal is in
`a second orientation, the wireless user terminal operates
`ina handset mode.
`
`[0005] GB2344500 describes a method of improving
`convergenceof an echo canceller in a full duplex speak-
`erphone, wherein the echo canceller includesa line echo
`canceller and an acoustic echo canceller.
`
`[0006] US2002/0041679 describes a far-end activity
`detector for a hands-free telephone that is configured to
`freeze operation of a steering functionality of a beam-
`former in the event that far-end acoustic energy exceeds
`near-end acoustic energy by more than said predeter-
`mined amount.
`
`Summary of the Invention
`
`Several tilt angle sensors are knownin the art
`[0010]
`and can be used. The simplest is a mechanical switch
`actuated by the telephone stand. Alternatively, a simple
`inclination meter can be used, such asthat disclosed by
`Ryan et al in US Patent 4,846,954. Or, a dual axis solid-
`state accelerometer may be used, such as the Analog
`Devices ADXL311.
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`the most expensive solution. As will be evident from the
`detailed description below,
`it may be advantageous to
`use the additional information provided by accelerome-
`ters to overcome non-linear effects due to vibrations in
`
`the adaptivefiltering used byfull-duplex audio algorithms
`and to linearise the loudspeaker response.
`[0012]
`Oncethe tilt sensor has been chosen and the
`tilt angle detected, the information may be used to adjust
`the frequency response of the handsfree receive and
`transmit signals. This information can also be used to
`select a previously stored set of coefficients for an adap-
`tive handsfree algorithm, as set forth by Popovic and
`McLeod in GB2344500. The information can further be
`
`used in a set that incorporates a conformal microphone
`and /or loudspeaker array to adjust the beamshape(i.e.
`beamformer coefficients) for the tilt angle of the set.
`
`Brief Description of the Drawings
`
`[0013] Embodiments of the present invention will now
`be described more fully with reference to the accompa-
`nying drawings, in which:
`
`is a schematic illustration of a telephone
`Figure 1
`incorporating a tilt sensor, according to a general
`aspect of the present invention;
`
`
`Detailed Description of the Preferred Embodiments
`
`[0014] Turning now to Figure 1, a loudspeaker tele-
`phone 10 is shown, commonly referred to as a "Speak-
`erphone". Loudspeaker telephone 10 includes a housing
`(not shown) with a cradle that accommodates a handset
`12 and an associated hookswitch 14 within the cradle. A
`
`display 16 and a keyboard 18 are provided on the hous-
`ing. At least one loudspeaker (an array of loudspeakers
`20 is shown), and at least one (an array of microphones
`22) are also provided in the housing to enable "hands-
`free" calls to be made.
`
`[0015] Disposed within the housing are the loudspeak-
`er telephone electronics generally indicated to by refer-
`ence number30. As can be seen, the loudspeaker tele-
`phone electronics 30 include a controller 32 coupled to
`a communications line 34 via an audio bus 36 and a line
`interface 38. The communications line 34 and the line
`
`interface 38 can either be analogue public switched tel-
`ephone network (PSTN), digital time-division multiplexed
`(TDM), wireless, packet switched (e.g. VoIP, ATM) or
`anyother voice carrier line interface. The controller 32 is
`also coupled to a computer (not shown) via a computer
`interface bus 3.
`
`[0016] A digital signal processor (DSP) 40 communi-
`cates with the controller 32 and with a number of coder/
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`decoders (CODECs) 42 and 44. CODEC 42is coupled
`to the handset 12 via amplifiers 50 and 52. CODEC(s)
`44 is coupled to the array of loudspeakers 20 and micro-
`phones 22 via amplifiers 54 and 56. The DSP 40 typically
`provides volume control 71, equalisation 70, beamform-
`ing 72, acoustic echo cancellation 73, hands-free func-
`tionality, tone generation, and other necessary function-
`ality for the operation of the loudspeaker telephone. The
`Figure 4 is a schematic cross-section view of a tel-
`controller 32, which communicates with the display 16
`ephoneasin Figure 1, where the tilt sensor compris-
`and keyboard 18, connects either one or both voice chan-
`nels of the loudspeaker telephone to the line interface 38.
`es a solid-state accelerometer to determine tilt angle
`
`via an analogue signal; [0017]Atilt sensor 19 provides an electrical signal to
`a conditioning circuit 58. The signal is processed by DSP
`40 to determine the state of the sensor. The output of
`DSP 40 is used either: to adjust the receive response or
`transmit response in the equalisation block 70; provide
`pre-recorded weights to an adaptive filter 73; adjust
`beamformer coefficients 72 for one or both of the micro-
`
`Figure 2 is a schematic cross-section view of a tel-
`ephoneasin Figure 1, wherethe tilt sensor compris-
`es mechanical switches;
`
`Figure 3 is a schematic illustration of a prior art in-
`clination meter using conductive fluid;
`
`Figure 5 is a schematic cross-section view of a tel-
`ephoneasin Figure 1, wherethe tilt sensor compris-
`es a solid-state accelerometer to determine tilt angle
`via a digitised signal;
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`Figure 6G is a block diagram of a speakerphone with
`direct control of receive and transmit signals using
`information from a tilt sensor, according to a first em-
`bodiment of the invention;
`
`Figure 7 is a block diagram illustrating the signal path
`fora prior art speakerphone using adaptivefilter; and
`
`phone and loudspeaker array. The tilt sensor signal is
`also processed to extract vibrational data that can be
`used to adjust adaptivefilter 73 (either separate from or
`integrated with the acoustic echo canceller). This vibra-
`tional data can also be used to ensurethat the loudspeak-
`er linearity is preserved by the use of active control.
`[0018] There are several possible embodiments and
`the following will describe the possible choices for the
`preferred embodiments from the simplest to the most
`Figure8is a block diagram illustrating the signal path
`a speakerphone with information from the tilt sensor
`complex. Finally, the preferred embodiment will be de-
`scribed in full detail.
`used to control operation of an adaptive filter, ac-
`cording to the preferred embodiment.
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`Firstly, three common methods of detecting tilt
`[0019]
`angle are described. One skilled in the art will be aware
`of these known methods, and their relative merits are
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`explained herein to afford a better understanding of the
`invention and its various embodiments.
`
`[0020] Turning to Figure 2, a telephone 201 is illustrat-
`ed with a stand 202 and switches 203 that are actuated
`
`tages mentioned having regard to Figure 4, but as the
`signal determination is implemented in the digital domain,
`moreflexibility is possible (e.g. the output can also be
`used for adaptive filtering of the speakerphone opera-
`as the stand is set to the desired angle. Selective activa-
`tion).
`tion of switches 203 controls a current applied to the
`[0024] Figure6illustrates a hardware-only implemen-
`
`switches via pull-up resistor 205 to generate a discrete
`tation of the invention, wherein discrete signals from the
`binary signal 204, which is used by the processor40 in
`tilt sensor 601 are used to adjust the frequency response
`Figure 1, to control performance characteristics of the
`of the transmit signal 602, receive signal 603, or both.
`speakerphone. The system of Figure 2 is easily imple-
`This is typically accomplished by varying the resistance
`mented asit is not complex and yields the reliability af-
`of an active filter and can be done either with an analogue
`forded by a mechanical system. However,it is limited by
`or digital signal. One skilled in the art will recognise that
`there is a plurality of solutions.
`the resolution afforded by the numberof switches imple-
`mented and maybe costly to implement, as it requires a
`[0025] According to the preferred embodimentof the
`plurality of mechanical devices.
`invention, acoustic performance adjustment is effected
`[0021] With reference to Figure 3, a tilt sensor 301 is
`using a digital signal processor. A general-purpose proc-
`illustrated similar to that disclosed by Ryan in US Patent
`essor may also be used but is less efficient. Figure 7
`4,846,954. The detection output may be implemented
`illustrates, generally, the signal path of a prior art speak-
`either as a binary output,asillustrated, or as a continuous
`erphone system. Becauseofits generality, Figure 7 omits
`analogue signal (not shown), to permit the resolution of
`the implementation details of the adaptivefilters, digital
`a plurality of angles. Placementofthe tilt sensor 301 re-
`beam formers, and frequency shaping filters, as they are
`quires precise positioning within the speakerphone. The
`not essential to understanding the invention. One skilled
`primary drawbackis that the sensor operates by encap-
`in the art will recognise that these are all controlled by a
`sulating a conductive fluid, which is not compatible with
`set of coefficients thatareinitially fixed and may be adap-
`contemporary high-speed electronic fabrication tech-
`tive. In Figure 7, the far end signal (receive) 725 is filtered
`niques.
`by a digital filter 731. This signal is then either directly
`sent to the output 722 or to the output via a beamformer
`[0022] Turning now to Figure 4, a micro-machinedin-
`tegrated circuit accelerometer 401 is mounted either on
`732. The signal is also fed to an adaptivefilter 734 that
`performs acoustic echo cancellation. The microphone
`the main circuit board 402 or on an auxiliary circuit board
`403 within a telephone set 404. Solid-state accelerome-
`signal(s) 723 are, if necessary, passed through a beam-
`former 733 before the output of the adaptivefilter 734 is
`ters are a preferred choice as they provide the required
`static acceleration, the technology is naturally compatible
`subtracted from the signal. It is then used as a feedback
`with electronic fabrication techniques, and they are more
`signal for the adaptivefilter 734 and alsofiltered 730 be-
`robust to handling and are less expensive than conven-
`fore being transmitted at the far end 724.
`tional piezo-electric accelerometers. In the preferred em-
`[0026] A person of skill
`in the art will appreciate that
`bodiment an Analog Devices ADXL311 accelerometer
`the signal components of Figure 7 may be part of a variety
`waschosen. The accelerometer 401 provides an output
`of telephonic devices and thatthe illustrated "four-wire”
`voltage from whicha reliable calculation of static accel-
`signals are appropriately processed to connectto a net-
`eration can be determined. The angle at which the device
`work. The filter coefficients for the receive frequency re-
`401 is placed is related to gravity by the simple relation-
`sponse 711 and the transmit frequency response 712,
`ship of sin’ (output/V,) where Vo is the voltage output
`as illustrated, may incorporate volume control. The
`corresponding to 1g of acceleration. In Figure 4, the out-
`beamforming coefficients for the loudspeakers 713 and
`put from the accelerometer 401 is filtered at 405 so as
`the microphones 715 may be dynamically allocated
`to pass only the D.C. component. Analogue circuitry 406
`based on user feedback or automatic speaker recogni-
`then detects the required resolution. A simple threshold
`tion as disclosed in US Patent Application 20020041679
`circuit can be used instead to yield a binary output. Gen-
`(Beaucoup). The adaptive filter for the echo canceller
`erally, more than two positions are required so the ana-
`may have coefficients 714 supplied to it in a manner as
`logue circuitry implements an inverse sine function and
`disclosed by Popovic and McLeod in GB2344500.
`is followed by multiple threshold detection yielding the
`[0027] Turning now to Figure 8, a signal diagram of
`required numberof positions for a particular application.
`the preferred embodiment is illustrated. In this embodi-
`[0023]
`Figure 5 is similar to Figure 4 in that a solid-
`ment, a solid-state accelerometer that has been digitised
`state accelerometer 501 is used. However, its output is
`as shownin Figure 5, is employed, but most of the func-
`digitised at 502 and a digital signal processor 503 is used
`tionality (except that requiring the vibrational data 822)
`to determine thetilt angle from the binary numerical out-
`can also be implemented using other techniques. Figure
`put. The conversion resolution, the signal processor ac-
`8 differs from Figure 7 in a number of important respects.
`curacy, and the accuracy of accelerometer 501 limit the
`Firstly, and additional input is provided, from the accel-
`precision, although all are typically within acceptable lim-
`erometer 820. The detecting block 850 usesthis digitised
`its. The configuration of Figure 5 has the same advan-
`signal 820 to create a control signal 821. In the preferred
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`embodiment, the detecting block 850 consists of a low
`passfilter to determine the DC component 802, an in-
`verse sine function 803 to calculated the tilt angle and
`finally a discrimination algorithm 804 that provides out-
`puts corresponding to the required increments set by the
`angular resolution 815. Thus, the output signal 821 is
`mapped, in a one to one ratio, to the tilt angles of interest
`in a specific implementation. This signal is then used to
`select one or moreofthe following: transmit equalisation
`and volume coefficients 810, receive equalisation and
`volume coefficients 811, microphone array beamformer
`coefficients 812, loudspeaker array beamformercoeffi-
`cients 813, acoustic echo canceller initial coefficients and
`operating parameters 814. The selection of these param-
`eters is accomplished by selecting a sub-array in this
`implementation (840,841 ,842,843,844).
`[0028] According to the preferred embodiment, the
`beamformers are fixed so the array of coefficients is cal-
`culated a priori. However, an adaptive beamformer may
`also be used wherein the coefficients are stored before
`
`changing from one tilt angle to the next. The information
`concerning the tilt angle is used to correct the coefficients
`due to the change in orientation of the set body relative
`to the tabletop.
`In co-pending U.K. Application No.
`0405790.7 filed March 15, 2004 by Dedieu et al., a uni-
`versal microphone array in a stand is disclosed with a
`mechanism to determine the set body attached to the
`stand and coefficients selected on that basis. This tilt
`
`angle detection mechanism adds another dimension to
`the coefficient array.
`[0029]
`One skilled in the art will appreciate that by in-
`corporating an appropriate detection block 850 any tilt
`angle detector may be used. The implementation of the
`selection of coefficients or parameters may also be ac-
`complished in a general-purpose processoror by the use
`of hardware and/or discrete circuitry.
`It will also be ap-
`preciated that cost considerations favour implementation
`of the digital signal processor in software.
`[0030] There are other significant differences between
`Figure & and Figure 7. Since an accelerometer is being
`used to detect the tilt angle, low frequency information
`can befiltered from the signal output 820 by the use of
`an appropriate filter 805, to correct for non-linearities in-
`troduced bythe vibration of the set. This is possible since
`the accelerometer is mounted either on the main printed
`circuit board of the set or on a daughter card. Non-line-
`arities in the loudspeaker operation can be corrected by
`the use of an appropriate adaptive filter that uses the
`vibrational information as input. Adding another canceller
`for vibrational effects enhances the acoustic echo can-
`
`celler 734 operation. Actual implementation will govern
`whether the additional canceller should be set before or
`
`after the main echo canceller. It may also be possible to
`incorporate this information in the main acoustic echo
`canceller block.
`
`[0031] Aperson of skill in the art may conceive of other
`embodiments that do not depart from the scope of the
`invention, which is defined by the claims appended here-
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`to.
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`Claims
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`1. Afixed telephone set (201, 404) resting on a surface
`provided with an adjustable stand (202) character-
`ised in that the fixed telephone set comprises a
`speakerphone (10), a sensor (19) for generating a
`signal
`indicative of the angle of tilt between said
`speakerphone (10) and said surface, a processor
`(40) for receiving said signal and in response adjust-
`ing at least one operational parameter affecting per-
`formance of said speakerphone (10), said at least
`one operational parameter comprising at least one
`of acoustic echo canceller initial coefficients, beam-
`forming coefficients for a microphone array, and
`beamforming coefficients for a loudspeaker array,
`and wherein said sensor (19) is selected from the
`group consisting of at least one mechanical switch,
`an inclination meter, and a dual axis solidstate ac-
`celerometer.
`
`2. The improvement of claim 1, wherein said at least
`one operational parameter further includes loud-
`speaker equalisation and volume adjustment.
`
`3. The improvement of claim 1, wherein said at least
`one operational parameter further includes micro-
`phone equalisation and volume adjustment.
`
`4. Amethod of optimizing speakerphone (10) perform-
`ance in a fixed telephone set (201, 404) resting on
`a surface provided with an adjustable stand (202),
`the method comprising the stepsof:
`
`detecting the angle oftilt between said speak-
`erphone (10) and said surface;
`adjusting at least one operational parameter in
`accordancewith said angle oftilt so as to affect
`performance of said speakerphone (10); and
`processinga tilt sensor (19) signal to extractvi-
`brational data and using said vibrational data to
`control at least one adaptive filter within said
`speakerphone (10) to either linearise the loud-
`speaker response or enhance the performance
`of an acoustic echo canceller within said speak-
`erphone (10);
`said atleast one operational parameter compris-
`ing at least one of acoustic echo canceller initial
`coefficients, beamforming coefficients for a mi-
`crophone array, and beamforming coefficients
`for a loudspeaker array.
`
`5. The method of claim 4, wherein said at least one
`operational parameter further includes loudspeaker
`equalisation and volume adjustment.
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`6.
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`The method of claim 4, wherein said at least one
`operational parameter further includes microphone
`equalisation and volume adjustment.
`
`Patentanspriiche
`
`1. Festnetz-Telefonapparat (201, 404), der auf einer
`Oberflache ruht, die mit einem verstellbaren Stander
`(202) ausgestattet ist, dadurch gekennzeichnet,
`dass der Festnetz-Telefonapparat Folgendes um-
`fasst: einen Sensor (19), zum Erzeugen eines Si-
`gnals, das indikativ ist fur den Neigungswinkel zwi-
`schen einem Lautfernsprecher (10) und der Ober-
`flache, einen Prozessor (40) zum Empfangen des
`Signals und, als Antwort darauf, zum Einstellen min-
`destens eines Betriebsparameters, der die Leistung
`des Lautfernsprechers (10) beeinflusst, wobei der
`mindestens eine Betriebsparameter mindestens ei-
`nes von Folgendem umfasst: erste Koeffizienten ei-
`nes akustischen Echounterdrtckers, strahlbildende
`Koeffizienten fir eine Mikrofonanordnung und
`strahlbildende Koeffizienten fur eine Lautsprecher-
`anordnung, und wobei der Sensor (19) ausgewahlt
`ist aus der Gruppe bestehend aus mindestens einem
`mechanischen Schalter, einem Neigungsmesser
`und einem zweiachsigen Festkérper-Beschleuni-
`gungsmesser.
`
`Verbesserung nach Anspruch 1, wobei der minde-
`stens eine Betriebsparameter ferner Lautsprecher-
`entzerrung und Lautstarkeregelung einschlieRt.
`
`Verbesserung nach Anspruch 1, wobei der minde-
`stens eine Betriebsparameter ferner Mikrofonent-
`zerrung und Lautstarkeregelung einschlieft.
`
`Verfahren zur Optimisierung der Leistung eines
`Lautfernsprechers (10) in einem Festnetz-Telefon-
`apparat (201, 204), der auf einer Oberflache ruht,
`die miteinem verstellbaren Stander (202) ausgestat-
`tet ist, wobei das Verfahren die folgenden Schritte
`umfasst:
`
`Erfassen des Neigungswinkels zwischen dem
`Lautfernsprecher (10) und der Oberflache;
`Einstellen mindestens eines Betriebsparame-
`ters entsprechend dem Neigungswinkel, damit
`die Leistung des Lautfernsprechers (10) beein-
`flusst wird; und
`Verarbeiten des Signals des Neigungssensors
`(19), um Vibrationsdaten zu extrahieren und Be-
`nutzen der Vibrationsdaten, um mindestens ein
`adaptives Filter
`innerhalb des Lautfernspre-
`chers (10) zu steuern, um die Lautsprecherant-
`wort entweder zulinearisieren oder die Leistung
`eines akustischen Echounterdruckersinnerhalb
`
`des Lautfernsprechers (10) zu steigern:
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`50
`
`55
`
`wobei der mindestens eine Betriebsparameter
`mindestens eines von Folgendem umfasst: er-
`ste Koeffizienten eines akustischen Echounter-
`
`drickers, strahlbildende Koeffizienten fur eine
`Mikrofonanordnung und strahlbildende Koeffizi-
`enten fir eine Lautsprecheranordnung.
`
`Verfahren nach Anspruch 4, wobei der mindestens
`eine Betriebsparameter ferner Lautsprecherentzer-
`rung und Lautstarkeregelung einschlieRt.
`
`Verfahren nach Anspruch 4, wobei der mindestens
`eine Betriebsparameter ferner Mikrofonentzerrung
`und Lautstarkeregelung einschlieft.
`
`Revendications
`
`Ensemble de téléphone fixe (201, 404) reposant sur
`une surface équipée d’un support ajustable (202),
`caractérisé en ce que l'ensemble de téléphone fixe
`comprend un poste a haut-parleur (10), un capteur
`(19) pour générer un signal indicateur de l’angle d’in-
`clinaison entre ledit poste a haut-parleur (10) et ladite
`surface, un processeur (40) pour recevoir ledit signal
`et ajuster en réponse au moins un paramétre opé-
`rationnel affectant la performance dudit poste a haut-
`parleur (10), ledit au moins un paramétre opération-
`nel comprenantdescoefficients initiaux d’annulateur
`d’écho acoustique et/ou des coefficients de forma-
`teur de faisceau pour un réseau de microphones
`et/ou des coefficients de formateur de faisceau pour
`un réseau de haut-parleurs, ledit capteur (19) étant
`sélectionné dans le groupe constitué d’au moins un
`interrupteur mécanique, un inclinométre, et un ac-
`célérométre a l'état solide a deux axes.
`
`Amélioration selon la revendication 1, dans laquelle
`ledit au moins un paramétre opérationnel comprend
`en outre une égalisation de haut-parleur et un ajus-
`tement de volume.
`
`Amélioration selon la revendication 1, dans laquelle
`le au moins un paramétre opérationnel comprend en
`outre une égalisation de microphone et un ajuste-
`ment de volume.
`
`Procédé d’optimisation d’une performance de poste
`a haut-parleur (10) dans un ensemble de téléphone
`fixe (201, 404) reposant sur une surface équipée
`d’un support ajustable (202), le procédé comprenant
`les étapes suivantes:
`
`détecter langle d’inclinaison entre ledit poste a
`haut-parleur (10) et ladite surface ;
`ajuster au moins un paramétre opérationnel
`conformément a l’angle d’inclinaison afin d’af-
`fecter la performance dudit poste a haut-parleur
`
`

`

`11
`
`EP 1 575 250 B1
`
`(10) ; et
`traiter un signal de capteur d’inclinaison (19)
`pour extraire les donnéesvibrationnelles et uti-
`liser lesdites données vibrationnelles pour con-
`tréler au moins un filtre adaptatifdansleditposte
`a haut-parleur (10) pour soit linéariser la répon-
`se du haut-parleur, soit améliorer la performan-
`ce d’un annulateur d’écho acoustique dans ledit
`poste a haut-parleur (10) ;
`ledit au moins un paramétre opérationnel com-=70
`prenant des coefficients initiaux d’annulateur
`d’écho acoustique et/ou des coefficients de for-
`mateur de faisceau pour un réseau de micro-
`phones et/ou des coefficients de formateur de
`faisceau pour un réseau de haut-parleurs.
`
`15
`
`5
`
`Procédé selon la revendication 4, dans lequel ledit
`au moins un paramétre opérationnel comprend en
`outre une égalisation de haut-parleur et un ajuste-
`ment de volume.
`
`Procédé selon la revendication 4, dans lequel ledit
`au moins un paramétre opérationnel comprend en
`outre une égalisation de microphone et un ajuste-
`ment de volume.
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`50
`
`55
`
`

`

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`REFERENCES CITED IN THE DESCRIPTION
`
`EP 1 575 250 B1
`
`This list of references cited by the applicant is for the reader's convenienceonly. It does not form part of the European
`patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be
`excluded and the EPO disclaimsall liability in this regard.
`
`Patent documentscited in the description
`
`*
`*
`+
`*
`«
`
`US 6122370 A [0002]
`US 6115620 A [0003]
`US 6411828 B [0003] [0004]
`US 6449363 B [0003]
`US 6510326 B [0003]
`
`*
`*
`+
`*
`
`GB 2344500 A [0005] [0012] [0026]
`US 20020041679 A [0006] [0026]
`US 4846954 A [0010] [0021]
`GB 0405790 A, Dedieu [0028]
`
`16
`
`