OMAR ACGAAOA
`
`US 20050041824A1
`
`as) United States
`a2) Patent Application Publication (10) Pub. No.: US 2005/0041824 Al
`
` Arndtet al. (43) Pub. Date: Feb. 24, 2005
`
`
`(54) HEARING AID HAVING AN ADJUSTABLE
`DIRECTIONAL CHARACTERISTIC, AND
`METHOD FOR ADJUSTMENT THEREOF
`
`(76)
`
`Inventors: FeErin una, ObermicheDED
`(DE);
`Harald
`Klemenz,Furth (DE);
`Hartmut Ritter, Neunkirchen am
`Brand (DE)
`
`Correspondence Address:
`SCHIFF HARDIN, LLP
`PATENT DEPARTMENT
`6600 SEARS TOWER
`CHICAGO,IL 60606-6473 (US)
`
`(21) Appl. No.:
`
`10/893,649
`
`(22)
`
`Filed:
`
`Jul. 16, 2004
`
`(30)
`
`Foreign Application Priority Data
`
`Jul. 16, 2003
`
`(DE). eceeecteeseeseeenees 103 31 956.5
`
`Publication Classification
`
`SL) Ute C7 annoninononnnninnnn HO4R 25/00
`(52) US. Ch cccssssssnsnnne 381/313; 381/312; 381/321
`
`(57)
`
`ABSTRACT
`
`In a hearing aid, as well as in a method for the operation of
`a hearing aid having a microphone system in which different
`directional characteristics can be set,
`the tonal quality is
`improved, particularly in a quiet hearing environment, by
`the signal delay for at least one microphone signal being
`increased so as to increase the transfer function in the
`frequency response of the microphone system, thus also
`improving the signal-to-noise ratio, by decreasing the pro-
`portion of the microphone noise in the microphone output
`signal.
`
`Level Measure ment
`& Control Device
`
`13
`
` Processing
`
`Swit chiha
`& Filter
`Uwit
`
`Uwit
`
`Exhibit 1011 Samsung Exhibit 1011
`
`Samsung v. Jawbone
`IPR2022-00213
`
`Page 01 of 08
`
`Samsung Exhibit 1011
`Page 01 of 08
`
`

`

`Patent Application Publication Feb. 24, 2005 Sheet 1 of 2
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`Samsung Exhibit 1011
`Page 02 of 08
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`Samsung Exhibit 1011
`Page 02 of 08
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`

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`Patent Application Publication Feb. 24, 2005 Sheet 2 of 2
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`Samsung Exhibit 1011
`Page 03 of 08
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`Samsung Exhibit 1011
`Page 03 of 08
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`

`

`US 2005/0041824 Al
`
`Feb. 24, 2005
`
`phones, whose output signals can be connected to one
`another via delay devices and the signal processing device,
`with different weightings, in order to produce an individual
`directional microphonecharacteristic. The preferred recep-
`tion direction (main direction) for the directional micro-
`phone system can be set individually to match an existing
`hearing situation.
`
`[0008] U.S. Pat. No. 5,524,056 discloses a hearing aid
`having an omnidirectional microphone and havinga first or
`higher order directional microphone. The low signal fre-
`quency range in the microphonesignal from the directional
`microphoneis amplified, and is matched to the microphone
`signal
`from the omnidirectional microphone. Both the
`microphone signal from the omnidirectional microphone
`and the microphonesignal from the directional microphone
`are supplied to a switching unit. When the switching unit is
`in a first switch position, the omnidirectional microphoneis
`connected to a hearing aid amplifier, and when the switching
`unit is in a second switch position, the directional micro-
`phoneis connected to a hearing aid amplifier. The switching
`unit can switch automatically as a function of the signal level
`of a microphonesignal.
`
`[0009] The known hearing aids with a directional micro-
`phone system have the disadvantagethat, in certain hearing
`situations, either the directionality of the microphone system
`is not optimally used, or a high degree of directionality leads
`to a clearly audible degradation in the tonal quality. In
`particular, when the level of the acoustic input signal is low,
`the signal-to-noise ratio becomes worse, and a hearing aid
`wearer perceives this in the form of disturbing microphone
`noise in a quiet environment.
`
`SUMMARYOF THE INVENTION
`
`[0010] An object of the present invention is to improve the
`tonal quality of a hearing aid having a directional micro-
`phone system.
`
`[0011] This object is achieved by a hearing aid according
`to the invention having a microphone system with at least
`two microphones, in order to make it possible to produce
`zero and first order directional characteristics. However,
`more than two microphonesare preferably used,so thatit is
`also possible to produce second and higher order directional
`characteristics. Furthermore, the hearing aid has a signal-
`processing unit for processing and frequency-dependent
`amplification of the microphone signal that is produced by
`the microphone system. The signals are normally emitted in
`the form of an acoustic output signal by means of an
`earpiece. However, other output transducers are also known,
`for example output transducers that produce vibration.
`
`[0012] For the purposes of the invention, a zero order
`directional characteristic is an omnidirectional directional
`
`HEARING AID HAVING AN ADJUSTABLE
`DIRECTIONAL CHARACTERISTIC, AND
`METHOD FOR ADJUSTMENT THEREOF
`
`BACKGROUND OF THE INVENTION
`
`[0001]
`
`1. Field of the Invention
`
`[0002] The present invention relates to hearing aids as
`well as methods for the operation of hearing aids of the type
`having a microphone system for picking up an acoustic input
`signal and for emission of a microphone output signal, a
`signal processing unit, and an output transducer for emission
`of an output signal.
`
`[0003]
`
`2. Description of the Prior Art
`
`[0004] Modern hearing aids use devices for classification
`of hearing situations. The transmission parameters of the
`hearing aid are automatically varied depending on the hear-
`ing situation. In this case, the classification may, inter alia,
`influence the method of operation of the interference noise
`suppression algorithms, and of the microphone system.
`Thus, for example, depending on the identified hearing
`situation, a choice is made (by discrete switching or by
`continuous overlaying) between an omnidirectional charac-
`teristic (zero directional characteristic) and significant direc-
`tionality of the microphone system (first or higher order
`directional characteristic). The directional characteristic is
`produced by using gradient microphonesor by electrically
`connecting a numberof omnidirectional microphonesto one
`another. Microphone systems such as these have a fre-
`quency-dependent transmission response, which is charac-
`terized by a considerable fall at low frequencies. The noise
`behavior of the microphones, on the other hand,
`is not
`dependent on the frequency, and is slightly amplified in
`comparison to an omnidirectional microphone. In order to
`achieve a natural tonal impression, the high-pass frequency
`response of the microphone system must be compensated for
`by amplification of the low frequencies. In the process, the
`noise that is present in the low frequency rangeis likewise
`amplified and,
`in some circumstances,
`is significantly
`audible in a disturbing manner, while quiet sounds are
`masked by the noise.
`
`[0005] German OS 101 14 101 discloses a method for
`processing an input signal in a signal-processing unit in a
`hearing aid. One embodimentof the known hearing aid has
`two microphones, with a delay element being connected to
`one microphone, the delay of which is set as a function of
`the result of a modulation analysis, in order to improve the
`signal processing and to reduce the interference noise.
`
`[0007] European Application 0 942 627 discloses a hear-
`ing aid having a directional microphone system with a signal
`processing device, an earpiece and a number of micro-
`
`Samsung Exhibit 1011
`Page 04 of 08
`
`[0006] PCT Application 00/76268 discloses a hearing aid
`having a signal processing unit and at least two micro-
`phones, which can be connected to one another in order to
`form directional microphone systems of different order, in
`characteristic that originates, for example, from a single
`which case the directional microphone systems may them-
`omnidirectional microphone, which is not connected to any
`selves be connected to one another with a weighting which
`other microphones. A microphone unit havingafirst order
`is dependent on the frequency of the microphonesignals
`directional characteristic (first order directional microphone)
`emitted from the microphones. The cut-off
`frequency
`may, for example, be produced by meansof a single gradient
`between adjacent frequency bands in which a different
`microphone, or by electrically connecting two omnidirec-
`weighting is provided for the microphonesignals can be set
`tional microphones.First order directional microphones can
`as a function of the result of a signal analysis.
`be used to achieve a theoretically achievable maximum
`directivity index (DI) value of 6 dB (hyperkidney).
`In
`practice, DI values of 4-4.5 dB are obtained on the KEMAR
`(a standard research dummy) with the microphones posi-
`
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`US 2005/0041824 Al
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`Feb. 24, 2005
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`tioned optimally and with the best matching of the signals
`that are produced by the microphones. Second and higher
`order directional microphones have DI values of 10 dB or
`more, and are advantageous, for example, for better speech
`comprehension. If a hearing aid contains a microphone
`system with, for example,
`three omnidirectional micro-
`phones, then, on this basis, it is possible to simultaneously
`produce microphone units with zero to second order direc-
`tional characteristics by suitable connection of the micro-
`phones.
`
`[0013] A single omnidirectional microphoneintrinsically
`represents a zero order microphoneunit. If, in the case of
`two omnidirectional microphones,
`the microphone signal
`from one microphoneis delayed and is subtracted from the
`microphone signal from the other microphone,
`then this
`results in a first order microphone unit. If, once again in the
`case of twofirst order microphone units, the microphone
`signal from one microphoneunit is delayed and is subtracted
`from the microphone signal from the second first order
`microphone unit, this results in a microphone unit with a
`second order directional characteristic. Microphone units of
`any desired order can be producedin this way, depending on
`the number of omnidirectional microphones.
`
`If a microphone system has microphone units of
`[0014]
`differentorder, then it is possible to switch between different
`directional characteristics, for example by connecting or
`disconnecting one or more microphones. Furthermore, any
`desired mixed forms between the directional characteristics
`
`of different order can also be produced by suitable electrical
`connection of the microphone units. For this purpose, the
`microphonesignals from the microphoneunits are weighted
`differently and are added, before they are further processed
`and amplified in the signal-processing unit in the hearing
`aid. It
`is thus possible to achieve a continuous, smooth
`transition between different directional characteristics, thus
`making it possible to avoid disturbing switching artifacts.
`
`In the case of two omnidirectional microphones,
`[0015]
`which are connected to form a microphone unit with a first
`order directional characteristic, the microphone signal delay
`for one of the microphone signals which originate from the
`microphones is normally set so as to compensate for the
`delay time of an acoustic input signal between the sound
`inlet openings of the microphones. The delay normally is
`chosento be less than or equal to this delay time. If the delay
`is less than the external delay time between the soundinlet
`openings of the microphones (referred to as an “endfire
`array”), then a directivity index which has been weighted
`with the articulation index (AI-DI) of up to 6.5 dB can be
`achieved on the KEMAR (a standardized artificial head), for
`example with a mixed form of first and second order.If this
`ratio between the internal delay and the external delay time
`is increased to considerably more than 1, then this AI-DI
`valuefirst falls rapidly and then becomesconstant at values
`of 4.5 to 5 dB, in a manner whichis very robust with regard
`to componenttolerances of the microphones and any further
`increase in the delay time. As the delay is increased, how-
`ever, the signal transmission response of the relevant micro-
`phone unit changes with respect to the sound signals that
`arrive at the microphone unit from the main direction. In this
`case, the main direction in general at least approximately
`matches the straight-ahead viewing direction of the hearing
`aid wearer, when the hearing aid is being worn. The fre-
`
`Samsung Exhibit 1011
`Page 05 of 08
`
`quency response of the microphone unit with respect to such
`acoustic input signals can be described, approximately, by
`the function:
`
`Heal —eie@estPin?
`
`Ifthe sum D,,,+D,,, of the external delay time and
`[0016]
`of the internal delay is doubled,this results in an increase in
`the microphoneoutput signal of about 6 dB, in the range of
`low signal frequencies, for example for a first order direc-
`tional microphone, and in an increase of about 12 dB for a
`second order directional microphone. In this case, the micro-
`phone noise produced by the microphones remains approxi-
`mately the same. The signal-to-noise ratio during directional
`microphone operation can thus be controlled with the aid of
`the internal, variable delay time. If this matching process is
`controlled adaptively as a function of the signal level of the
`acoustic input signal, then a high signal-to-noise ratio with
`AI-DI values of 4.5 to 5 dB, which are sufficient for these
`levels, can be achieved in a quiet environment. When the
`signal
`level of the acoustic input signal rises, a lower
`signal-to-noise ratio can be accepted, since the higher micro-
`phone noise associated with this is masked by the acoustic
`input signal. A variable AI-DI value is thus possible by
`adjusting the delay as a function of the situation,
`thus
`allowing better suppression of an interference signal from
`the side or from the rear when the acoustic input signal is
`loud.
`
`[0017] The frequency response of a multiple microphone
`system according to the invention generally has a direction-
`ality operation behavior such that high frequencies are more
`strongly emphasized when the acoustic input signal level is
`low, while the gain for high frequencies is automatically
`reduced whenthe environmentis loud,as in the case of AGC
`(automatic gain control). As an example, this applies to a
`conventional mixed form of first and second order direc-
`tionalities. If required, an equalization filter can also be
`provided for a hearing aid according to the invention, which
`can be used to compensate for the AGC effect caused by the
`invention.
`
`[0018] The matching of the internal delay time, or of the
`internal delay times, as a function ofat least one microphone
`signal according to the invention may be carried out in
`discrete steps. However, the matching processis preferably
`carried out continuously with smooth transitions, so that the
`control process does not cause any switching artifacts.
`
`In an embodiment of the invention setting of the
`[0019]
`delay of the microphonesignal is not controlled directly by
`the signal level of the acoustic input signal, but by the signal
`level of the microphone output signal. For example, in an
`environmentalsituation in which there is no useful signal, or
`virtually no useful signal, from the direction in which the
`hearing aid wearer is looking, but the interference noise
`from the side or from the rear is relatively loud, then, in the
`case of a hearing aid according to the invention, exclusive
`consideration of the acoustic input signal picked up by an
`omnidirectional microphone would leadto relatively strong
`directionality being set, with increased microphone noise
`associated with this. Since, in the described situation, the
`interference signal
`is virtually masked out by the high
`directionality, the hearing aid wearer can be supplied with
`greater microphone noise, which is found to be disturbing.
`If the microphone signal that is actually emitted from the
`microphone system is taken into account, it would then be
`
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`Feb. 24, 2005
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`possible to reduce the directionality according to the inven-
`tion to such an extent that the microphone noiseis at least
`partially masked by the acoustic interference signal, which
`is then not suppressed to such an extent.
`
`then this results in the microphones 1, 2 and 3 forming a
`microphone system 1, 2, 3 with a second order directional
`characteristic, whose microphone signal R2 is produced at
`the output of the adder 9.
`
`[0020] The invention offers the advantage that this adap-
`tive control of the internal delay of a microphone signal
`allows the signal-to-noise ratio of the higher order multiple
`microphone system (n > 1) to be controlled as a function of
`the signal level of the acoustic input signal and, possibly,
`also as a function of the incidence direction of the acoustic
`input signal. Particularly when the input signal levels are
`quiet,
`this makes it possible to avoid a high level of
`microphonenoise, which is found to be disturbing.
`
`[0021] The invention can be used for all known hearing
`aid types with an adjustable directional microphone, for
`example for hearing aids which can be worn behindtheear,
`hearing aids which can be worn in the ear,
`implantable
`hearing aids or pocket hearing aids. Furthermore, the hear-
`ing aid according to the invention may also be part of a
`hearing aid system which comprises a numberof appliances
`for supplying someone with hearing problems, for example
`part of a hearing aid system with two hearing aids which are
`worn on the head, for binaural supply, or part of a hearing
`aid system comprising one appliance which can be worn on
`the head, and a processor unit which can be worn on the
`body.
`
`DESCRIPTION OF THE DRAWINGS
`
`[0025] The three microphone signals RO, R1 and R2 are
`supplied to a switching and filter unit 10,
`in which it is
`possible to switch between the different microphonesignals
`RO, R1 and R2, or in which the microphone signals RO, R1
`and R2 are differently weighted and added. The resultant
`microphone output signal RA whichis emitted at the output
`of the switching and filter unit 10 is, finally, supplied to a
`signal processing unit 11, in which the further processing
`and frequency-dependent amplification of the microphone
`output signal RA are carried out in order to compensate for
`the individual hearing loss of a hearing aid wearer. Finally,
`the processed microphonesignal is converted to an acoustic
`signal, for emission through an earpiece 12 into the auditory
`channel of the hearing aid wearer.
`
`[0026] The hearing aid according to the exemplary
`embodiment also has a level measurement and control
`device 13,
`to which the microphone signal RO from the
`omnidirectional microphone 1 is supplied. This microphone
`signal is used to detect the signal level of the acoustic input
`signal that is currently arriving at the microphone 1. The
`level measurement and control device 13 uses this signal
`level to produce parameters for adjustment of the delay in
`the delay units 4A, 4B and 7, thus making it possible to
`influence the directionality, and if necessary to reduce the
`microphonenoise, according to the invention.
`
`[0022] FIG. 1 is a block diagram of a hearing aid with
`three omnidirectional microphones in accordance with the
`invention.
`
`[0023] FIG. 2 showsthe signal transmission response of
`a directional microphone system according to the invention,
`for two different delay times.
`
`DESCRIPTION OF THE PREFERRED
`EMBODIMENTS
`
`In order to assess whether and to what extent a
`[0027]
`hearing aid wearer perceives microphonenoisein a specific
`environmental situation, current hearing aid settings are
`preferably also taken into account, in addition to audiomet-
`ric data relating to the hearing aid wearer (rest hearing
`threshold, masking threshold). These settings also relate in
`particular to the microphone system. For example, in the
`environmentalsituation with a high interference sound com-
`ponent, the evaluation of the microphone signal RO at the
`[0024] FIG.1isa circuit diagram of the basic components
`input of the microphonesystem results in the finding that the
`of a hearing aid with a directional microphone system
`signal level of the acoustic input signal is high. However,it
`according to the invention. The microphone system com-
`is possible in this environmental situation to largely suppress
`prises three omnidirectional microphones 1, 2 and 3. The
`the interference signal by setting the microphone system to
`microphonesignal that originates from the microphone2 is
`have high directionality, so that only a relatively quiet output
`delayed in a delay unit 4A,is inverted by an inverter 5A, and
`signal is supplied to the hearing aid wearer. The microphone
`is added in an adder 6A to the microphone signal RO which
`noise in this output signal can then possibly assumea clearly
`originates from the microphone1. Overall, the inversion and
`perceptible proportion of this output signal. For this reason,
`addition results in the microphone signal that originates
`the delay time settings according to the invention preferably
`from the microphone 2 being subtracted from the micro-
`also take account of the microphone signals that originate
`phonesignal that originates from the microphone 1. The two
`from a directional microphone unit.
`In the exemplary
`omnidirectional microphones 1 and 2 thus form a micro-
`embodiment, these are the microphone signals R1 and R2.
`phone unit 1, 2 with a first order directional characteristic,
`Furthermore, it is also possible to evaluate the microphone
`from which the microphone signal R1 originates. In the
`output signal RA that
`is produced at
`the output of the
`same way, the microphone signal which originates from the
`switching and filter unit 10 and is supplied to the signal-
`microphone 3 is delayed in a delay unit 4B, is inverted by
`processing unit 11 for further processing. Taking account of
`an inverter 5B andis addedin an adder6B to the microphone
`the hearing aid characteristics and settings,it is then possible
`signal which originates from the microphone 2. The micro-
`to use this signal to directly determine what signal level is
`phones 2 and 3 also thus form a microphone umit 2, 3 with
`actually being supplied to the hearing aid wearer in response
`a first order directional characteristic, the microphonesignal
`to the current acoustic input signal, and the proportionofthis
`of which is produced at the output of the adder 6B. If the
`that is represented by the microphonenoise.
`microphone signal which originates from the microphone
`unit 2, 3 is in turn delayed in a delay unit 7 and is inverted
`in an inverter 8 and is added in an adder 9 to the microphone
`signal R1 which originates from the microphone unit 1, 2,
`
`Samsung Exhibit 1011
`Page 06 of 08
`
`[0028] The instantaneous environmental situation can be
`identified well by evaluation of both a microphone signal
`that is produced by an omnidirectional microphone and the
`
`Samsung Exhibit 1011
`Page 06 of 08
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`Feb. 24, 2005
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`microphone signals from microphone units with a direc-
`tional characteristic.
`In particular,
`it
`is also possible to
`estimate whether the proportion of the microphone noise in
`the microphone signal which is provided for further pro-
`cessing in the signal processing unit 11 can be perceived by
`the hearing aid wearer with the hearing aid settings at that
`time. An excessively high proportion of microphonenoise in
`the microphone output signal leads to the level measurement
`and control device 13 for at least one of the delay units 4A,
`4B or 7 increasing the delay setting until the proportion of
`the microphone noise in the microphone output signal
`reaches a value which is considered to be acceptable.
`
`[0029] Conversely, if the microphone output signalis at a
`high signal level, and the microphone noise makes up only
`a small proportion of this, then relatively short delay times
`may be set for all three delay units 4A, 4B and 7, thus
`increasing the directionality and suppressing the interfer-
`ence sound component
`in the acoustic input signal.
`In
`particular, the low frequencies also are reduced, and the high
`frequencies increased, during this transition. In order to
`avoid this effect, the level measurement and control device
`13 also acts on the switching andfilter unit 10, so that the
`last-mentioned effects are largely compensated for by suit-
`able filter settings.
`
`[0030] Thus, overall, the invention provides the capability
`to change the setting of the directional microphone system
`in a quiet hearing environment, so as to prevent clearly
`audible and disturbing microphonenoise. On the other hand,
`however, the advantages of a higher order directional micro-
`phone system are fully exploited in a loud hearing environ-
`ment.
`
`[0031] Another advantageous feature of the hearing aid
`according to the exemplary embodimentis that there is an
`electrical connection between the level measurement and
`control device 13 and the signal-processing unit 11. The
`evaluation of the microphone signal or microphonesignals
`in the level measurementand control device 13 can thus also
`be used for automatic situation identification, and thus for
`adaptive control of the signal processing in the signal
`processing unit 11. Furthermore, it may also be possible to
`manually set hearing programs for different hearing envi-
`ronments in the signal processing unit 11, with some of these
`hearing programsinfluencing the delay times according to
`the invention, while others do not. Provision is thus also
`made for signals to be transmitted from the signal-process-
`ing unit 11 to the level measurement and control unit 13.
`
`[0032] The signal processing in the hearing aid according
`to the exemplary embodiment may be carried out using
`analog,digital or combined circuit technology. Furthermore,
`the signal processing mayalso be carried out in parallel, in
`adjacent frequency bands (channels). The directional char-
`acteristic of the microphone system preferably also is set in
`frequency bands.
`
`[0033] FIG. 2 shows the effects of adaptive directional
`microphonesetting according to the invention,illustrated in
`the form of a graph. A first characteristic A showsthe signal
`transmission response of a directional microphone system
`for one specific setting of the signal delay in the delay units
`in the directional microphone system.
`In this case,
`the
`internal delay is shorter than the external delay time of an
`acoustic signal that arrives at the microphone system from
`the front (viewing direction), with the microphones (and
`
`Samsung Exhibit 1011
`Page 07 of 08
`
`their sound inlet openings) being arranged one behind the
`other in the viewing direction. In a mixed form offirst and
`second order microphone units, whose microphonesignals
`are processed further jointly, it is thus possible to achieve a
`directionality value, weighted with the articulation index
`AI-DI of up to 6.5.
`
`[0034] The frequency response of the microphone system
`is described by a function in the form:
`Heal —eieesti?
`
`In this case, the characteristic shows the typical
`[0035]
`high-pass behaviorof a higher order directional microphone
`system. According to the invention, the transmission char-
`acteristic A is selected in particular in a loud hearing
`environment.
`
`If the signal level of the acoustic input signal falls,
`[0036]
`or the proportion of the microphonenoise in the microphone
`output signal which is produced by the microphone system
`is dominant, then the signal delay for at least one micro-
`phone signal
`in the directional microphone system is
`increased, which, in the event of the internal delay being
`doubled in comparison to the external delay time, results, for
`example,
`in a transition from the signal
`transmission
`response of the directional microphone system from the
`characteristic A to the second illustrated characteristic B.
`
`This is higher by about 6 dB than the characteristic A. In
`contrast, the microphone noise remains approximately con-
`stant. Although the internal signal delay initially results in
`the AI-DI value decreasing,it then becomes constant, how-
`ever, at values of 4.5 5 dB, even if the internal delay is
`increased further,
`thus still resulting in relatively good
`directionality. Thus, overall, the signal-to-noise ratio in the
`directional microphone mode can be controlled with the aid
`of the internal delay times, which can besetelectrically.
`
`[0037] Although modifications and changes may be sug-
`gested by those skilled in the art, it is the intention of the
`inventors to embody within the patent warranted hereonall
`changes and modifications as reasonably and properly come
`within the scope of their contribution to the art.
`
`We claim as our invention:
`
`1. A hearing aid comprising:
`
`a first omnidirectional microphone producing a first
`microphone signal;
`
`a second omnidirectional microphone producing a second
`microphone signal;
`
`said first and second omnidirectional microphones being
`electrically connected to each other to form a micro-
`phone unit, said microphone unit comprising a delay
`element to which one of said first and second micro-
`
`phonesignals is supplied for delaying said one of said
`first and second microphone signals by a delay time
`with respect
`to the other of said first and second
`microphonesignals for giving a microphoneunit signal
`produced by said microphone unit a directional char-
`acteristic;
`
`for
`an adjustment unit connected to said delay unit
`adjusting said delay time dependenton a signal level of
`an acoustic input signal to at least one of said first and
`second omnidirectional microphones;
`
`Samsung Exhibit 1011
`Page 07 of 08
`
`

`

`US 2005/0041824 Al
`
`Feb. 24, 2005
`
`a signal processor for processing said microphone unit
`output signal to produce a processed signal; and
`
`an output transducer for converting said processed signal
`into an audio signal and for emitting said audio signal.
`2. A hearing aid comprising:
`
`a first omnidirectional microphone producing a first
`microphone signal;
`
`a second omnidirectional microphone producing a second
`microphone signal;
`
`a third omnidirectional microphone producing a third
`microphone signal;
`
`said first and second omnidirectional microphones being
`electrically connected to each other to form a micro-
`phoneunit producing a microphone unit signal having
`a directional characteristic;
`
`said microphone unit and said third omnidirectional
`microphonebeingelectrically connected to each other
`to form a microphone system, said microphone system
`including a delay unit for delaying one of said micro-
`phone unit signal and said third microphone signal by
`a delay time relative to the other of said microphone
`unit signal and said third microphonesignal for giving
`a microphone system signal produced by said micro-
`phone system a directional characteristic;
`
`for
`an adjustment unit connected to said delay unit
`adjusting said delay time dependenton a signal level of
`an acoustic input signal to at least one of said first,
`second or third omnidirectional microphones;
`
`a signal processor supplied with said microphone system
`signal for producing a processed signal therefrom; and
`
`an output transducer supplied with said processed signal
`for converting said processed signal into an output
`audio signal and for emitting said output audio signal.
`3. A method for adjusting a directional characteristic of a
`microphone unit in a hearing aid, said microphone unit
`comprising two omnidirectional microphones each produc-
`ing a microphonesignal, comprising the steps of:
`
`from a first of said
`delaying the microphone signal
`omnidirectional microphones by a delay time relative
`to the microphone signal from a second of said omni-
`directional microphones, to produce a delayed micro-
`phonesignal, and subtracting the delayed microphone
`signal from the microphonesignal from the second of
`said omnidirectional microphones to give a micro-
`phone unit signal produced by said microphone unit a
`directional characteristic; and
`
`setting said delay time dependenton a signal level of an
`acoustic input signal to at least one of said omnidirec-
`tional microphones.
`4. A method as claimed in claim 3 comprising setting said
`delay time dependent on a signal level of the microphone
`signal from one of said omnidirectional microphones.
`5. A method as claimed in claim 3 comprising increasing
`said delay time as said signal level decreases.
`6. A method as claimed in claim 3 comprising changing
`said delay time in steps as said signal level changes.
`
`7. Amethod as claimed in claim 3 comprising changing
`said delay time continuously as said signal level changes.
`8. A method as claimed in claim 3 wherein said micro-
`phoneunit signal is subject to an increase in signal level as
`said delay time is increased, and comprising the additional
`step of automatically compensating for said increase in said
`signal level of said microphone unit