Hearing aid and method for operating same

Abstract

The invention relates to a hearing aid (2) which has a control unit (26) that has a communication frontend (6), comprising a resonant circuit (8) and a transceiver (10), for a communication using electromagnetic induction, wherein the transceiver (10) can be switched between a first communication channel (22) with a first frequency (f1) and a second communication channel (24) with a second frequency (f2), and the control unit (26) is designed to switch the transceiver (10) between the first and second communication channel (22, 24) for a selective communication on one of the two communication channels (22, 24). The invention additionally relates to a corresponding method for operating such a hearing aid (2).

Description

[0001] Description

[0002] Hearing aid and method for its operation

[0003] The invention relates to a hearing aid and a method for its operation.

[0004] A hearing aid is used to provide hearing assistance to a hearing-impaired user and to compensate for the user's hearing loss. For this purpose, the hearing aid typically has a microphone, signal processing, and a receiver. The microphone generates an input signal, which is fed to the signal processing unit. The signal processing unit modifies the input signal and thereby generates an output signal. To compensate for a hearing loss, the input signal is amplified with a frequency-dependent gain factor, for example, based on the user's audiogram. The output signal is finally transmitted to the user via the receiver. In this way, sound signals from the environment are transmitted to the user in an appropriately modified form. The input signal and the output signal are both electrical signals. The sound signals from the environment and the sound signals emitted by the receiver, in contrast, are acoustic signals.

[0005] A hearing aid is also a mobile device, i.e. it is regularly worn by the user for long periods of time and is small in size, in the case of a hearing aid the dimensions are a few centimeters at most. As a mobile device, the hearing aid generally benefits from communication with other devices, e.g. a smartphone, tablet, television or computer. Communication within the hearing aid itself, especially between two individual devices of a binaural hearing aid, is also advantageous. Communication can be achieved in many different ways, two particularly advantageous communication technologies are NFMI (near field magnetic induction) in general, e.g. RFID (radio frequency identification), and NFC (near field communication). Communication using NFC in particular is defined by a corresponding standard.

[0006] In this case, several different communication options are to be integrated into a hearing aid. Combining several corresponding communication technologies in a single device is difficult in that each of these technologies requires corresponding components, which in turn require corresponding installation space, be it as an analog, electrical component or as a function digitally integrated into a digital chip. In hearing aids in particular, the available installation space for both analog components and digital functions is often very limited, typically more so than with smartphones or computers. This results from the smaller dimensions of a hearing aid, which is regularly worn in, on, or behind the ear and is generally intended to be as unobtrusive as possible. Additional components also regularly result in additional costs.

[0007] Against this background, the object of the invention is to integrate several different communication options into a hearing aid in the most space-saving and cost-effective manner possible. To this end, a correspondingly improved hearing aid and a suitable method for its operation are to be provided.

[0008] The object is achieved according to the invention by a hearing aid having the features of claim 1 and by a method having the features of claim 14. Advantageous embodiments, further developments and variants are the subject of the dependent claims. The statements in connection with the hearing aid also apply mutatis mutandis to the method and vice versa. If steps of the method are specified below, preferred embodiments for the hearing aid result from the fact that the hearing aid has a control unit (control circuit) which is designed to carry out one or more of these steps. The hearing aid has a communications front end (shortly "front end"). The communications front end has a resonance circuit and a transceiver for communication by means of electromagnetic induction. Communication is understood in particular to mean the sending and / or receiving of signals which contain data, in short a data exchange.Such signals sent and / or received by the hearing aid (or a single device) are electromagnetic signals.

[0009] The resonant circuit is connected to the transceiver and serves to transmit and receive corresponding signals during communication. The resonant circuit acts as an antenna. Suitably, the resonant circuit is an oscillating circuit with an inductance and a capacitance that define a resonant frequency of the resonant circuit. During communication via electromagnetic induction, the inductance then serves as an antenna. The resonant frequency is, in particular, a carrier frequency of the signals during communication. The resonant circuit is, in particular, not part of the transceiver but is formed separately from it.

[0010] The transceiver has in particular a transmitter and a receiver.

[0011] The transmitter converts a digital signal generated by the hearing aid and containing data to be transmitted into a transmission signal, which is then emitted by the resonant circuit. The receiver converts a reception signal, which is received by the hearing aid via the resonant circuit and contains data to be received, into a digital signal, which is then further processed or can be further processed by the hearing aid. The digital signal is present, in particular, in a baseband. The transmission signal and the reception signal are present in analog form at a reception frequency and a transmission frequency, respectively, which are preferably identical.

[0012] In the hearing aid described here, the transceiver, or more precisely its receiver and / or transmitter, and optionally also the resonant circuit, is switchable between a first communication channel at a first frequency and a second communication channel at a second frequency. In other words, regardless of whether the resonant circuit is switchable, at least the transceiver is switchable. The first and second frequencies are, in particular, carrier frequencies of the two communication channels and thus also define the transmit frequency and the receive frequency. Preferably, one or both communication channels are defined by a standard, in the latter case, in particular by different standards.

[0013] As already indicated, the hearing aid additionally has a control unit, which is preferably part of a digital chip of the hearing aid. The control unit is in particular connected to the communication front end or part thereof. The control unit is designed to switch the transceiver between the first and the second communication channel, for selective communication on one of the two communication channels, i.e. at one of the two frequencies. This advantageously enables the hearing aid to at least receive and preferably also send corresponding signals and thus data on two different communication channels by means of the same communication front end and specifically by means of the same transceiver. However, simultaneous communication on both communication channels is in particular not possible but is excluded by principle.

[0014] The hearing aid suitably additionally has an input transducer, a signal processing unit, and an output transducer. The input transducer is preferably a microphone, the output transducer is preferably an earpiece. The hearing aid is in particular assigned to a single user and is used solely by that user. Preferably, the hearing aid serves to supply a hearing-impaired user and to compensate for the user's hearing loss. For this purpose, the input transducer generates an input signal, which is fed to the signal processing unit. The signal processing unit is in particular part of the digital chip. The signal processing unit modifies the input signal and thereby generates an output signal, which is thus a modified input signal. To compensate for the hearing loss, the input signal is amplified with a frequency-dependent gain factor, for example, according to an audiogram of the user.The output signal is finally output to the user via the output converter.

[0015] Preferably, the first communication channel is an NFC channel and the second communication channel is a different NFMI channel. Thus, the transceiver is a combined NFC and NFMI transceiver.

[0016] In principle, NFC can also be considered an NFMI technology. However, in the configuration described here, with an NFC channel on the one hand and a different NFMI channel on the other, the term NFMI channel refers to a proprietary NFMI technology that does not conform to the NFC standard and differs primarily in the frequency used and optionally, for example, also in a different modulation or coding method. The NFMI channel referred to here therefore does not conform to the NFC standard and is therefore not simply an alternative NFC channel.

[0017] Suitably, the first frequency is 13.56 MHz and the second frequency is 10.6 MHz. In this embodiment, the first frequency is particularly suitable for communication according to the NFC standard, and the second frequency is suitable for a different, deviating NFMI communication, in particular according to a manufacturer's own or proprietary specification. However, one or both of the frequencies can also have other values.

[0018] In the following, it is assumed, without loss of generality, that the first communication channel is an NFC channel at a first frequency of 13.56 MHz and that the second communication channel is an NFMI channel at a second frequency of 10.6 MHz.

[0019] The two communication channels are preferably, but not necessarily, used for communication between different devices, i.e. one communication channel is not merely a substitute for the other communication channel, but expediently enables a different connection. In a particularly preferred embodiment, the hearing aid is a binaural hearing aid with two individual devices that are used by the same user. In particular, when used as intended, one of the individual devices is worn by the user on the left side of the head and the other individual device on the opposite, right side of the head. One of the two communication channels, preferably the NFMI channel, is designed for unidirectional or bidirectional communication between the two individual devices.The other of the two communication channels, preferably the NFC channel, is then not used for communication between the individual devices, but preferably for communication with an additional device separate from the hearing aid. Communication with the additional device occurs either from both individual devices or only from one of the individual devices. It is also fundamentally possible for one individual device to serve as a relay for the other individual device when communicating with the additional device (with a corresponding time offset due to the dual use of the transceiver, e.g., in a time-division multiplexing process). The additional device is, for example, a smartphone, tablet, television, computer, or the like. In other words, one of the two communication channels is preferably used exclusively for internal communication, i.e.for communication between the individual devices and thus within the hearing aid, and the other of the two communication channels is preferably used exclusively for external communication, i.e., for communication between the hearing aid and an additional device, i.e., another device that is, in particular, independent of the hearing aid. "Independent" is understood in particular to mean that the additional device is independent, i.e., can also be used without the hearing aid, has its own power supply, and / or is mechanically decoupled from the hearing aid.

[0020] In this case, it was recognized that the communication front end of a hearing aid with an NFMI channel, in particular for communication between the two individual devices, can also be used for NFC communication in a particularly simple way, so that corresponding components do not have to be additionally integrated into the hearing aid. Rather, the existing communication front end is only slightly modified in order to implement communication via an NFC channel, in particular in accordance with the NFC standard, in addition to the existing NFMI channel (which is not an NFC channel). Accordingly, in addition to the general NFMI functionality (e.g. data exchange between the individual devices), the hearing aid then also has access to a specific NFC function, e.g. Bluetooth pairing, charger detection, localization, automatic configuration of the hearing aid, identification of additional devices to the hearing aid or vice versa.Accordingly, only a single communication frontend is used for communication on different communication channels.

[0021] The essential adaptation in this case is the described switchability of the transceiver (this is to be distinguished from an optional switchability of the separate resonant circuit). In other words: the transceiver is adjustable such that a signal is or can be received and / or transmitted either at the first frequency or at the second frequency. For this purpose, the receiver and / or the transmitter are controlled accordingly and, in particular, a receive frequency of the receiver or a transmit frequency of the transmitter is set such that reception and / or transmission takes place optionally on the first or the second frequency (the control unit is designed accordingly to carry this out). Suitably, the communications frontend has an adjustable clock generator for this purpose for specifying a clock (also: clock rate, clock frequency) for the transceiver.The clock generator is connected to the receiver and / or the transmitter in such a way that the clock is passed on to the receiver and / or the transmitter accordingly. The clock then determines the receive frequency and / or the transmit frequency accordingly. Preferably, the clock even corresponds to a carrier frequency, i.e. the receive frequency or the transmit frequency of the transmitter for communication on the respective communication channel. In other words: the clock generator directly specifies a carrier frequency for the transceiver; this carrier frequency (the clock) can then be set in order to switch between different communication channels. The clock generator is also referred to as a local oscillator (LO) or "clock circuit". The control unit is then designed to set the clock of the clock generator in order to switch the transceiver, namely to switch the clock between two different clocks.By switching the clock, the first or second communication channel is used depending on the setting (at least unidirectional, preferably bidirectional).

[0022] In a suitable embodiment, the clock is switchable between the first frequency and the second frequency, i.e., in particular, between two different carrier frequencies for the transceiver. Thus, the receiver uses the clock to downconvert the received signal from its carrier frequency, in particular to the baseband. Conversely, the transmitter uses the clock to upconvert the transmitted signal, in particular from the baseband to the carrier frequency. However, the details of the respective conversion are not relevant here.

[0023] Alternatively, a suitable configuration is one in which the frequency (in particular the carrier frequency) of one of the communication channels is not precisely matched, but rather in which the clock is switchable between one of the two frequencies and a third frequency that is so close to the other of the two frequencies (in particular the carrier frequencies) that a sideband to this other frequency lies within a carrier frequency band, in particular the receive frequency band, of the transceiver. This is based on the consideration that the data may be located in a sideband to the carrier frequency, and it is therefore sufficient to receive only a corresponding frequency range on one side of the carrier frequency.This is also referred to as "single sideband recovery" and is especially possible with an NFC channel, since the NFC standard defines data transmission through modulation, which leads to sidebands to the left and right of the carrier frequency in the corresponding signal. Accordingly, it is sufficient to set the clock and thus the reception frequency of the receiver such that it lies on one side of the carrier frequency and the reception frequency band, which lies around the reception frequency, then only covers one of the two sidebands. The reception frequency and the reception frequency band are particularly dependent on a subcarrier frequency (e.g., 848 kHz according to the NFC standard). The reception frequency is then the sum or difference of the carrier frequency (i.e., the first or second frequency) and the subcarrier frequency. The reception frequency band then extends, for example,above or below the carrier frequency (alternatively, the carrier frequency is included) across the corresponding sideband and is arranged, for example, symmetrically (alternatively, asymmetrically) to the receive frequency. A suitable bandwidth for the receive frequency band is, for example, 1.5 MHz to 2 MHz.

[0024] Since both communication channels cannot be used simultaneously, in a suitable configuration, one of the two communication channels is a standard channel (preferably the NFMI channel) and the other of the two communication channels is a demand channel (preferably the NFC channel). The standard channel is set and used by default, while the demand channel is only used on an as-needed basis, when a specific signal needs to be sent or received on this communication channel.

[0025] Preferably, the communications frontend has a power detector for measuring power at the frequency of the demand channel, and the control unit is designed to switch the transceiver from the standard channel to the demand channel if the power detector measures a power above a predetermined threshold at the frequency of the demand channel. The transceiver is therefore switched from the standard channel to the demand channel precisely when a signal is received on the demand channel. For this purpose, the power detector is specifically set to the frequency of the demand channel (e.g. 13.56 MHz for the NFC channel) and connected to the resonant circuit in order to receive the received signal from it and measure the power therein at the frequency of the demand channel. If this power exceeds the predetermined threshold, the transceiver is switched to the demand channel.

[0026] The control unit is suitably configured to switch the transceiver back from the demand channel to the standard channel after a predetermined time interval has elapsed (so-called "timeout") or after communication via the demand channel has been completed. Completion of communication is detected, in particular, by the control unit and indicated, for example, by corresponding data transmitted at the end of the signal.

[0027] The resonant circuit does not necessarily have to be adjusted, but if necessary supplies a correspondingly attenuated signal at at least one of the two frequencies, with which communication is still possible. Preferably, however, the resonant circuit has an adjustable resonant frequency and the control unit is designed to set the frequency of the currently used communication channel as the resonant frequency of the resonant circuit. Analogous to switching the transceiver depending on the currently used frequency, the resonant circuit is then also switched accordingly in order to achieve optimal transmission and reception performance at the frequency of the respective communication channel. This configuration is only optional in itself, but improves communication, because otherwise one of the two communication channels would only be received and / or transmitted in an attenuated manner.The resonant frequency is conveniently adjusted by adjusting the capacitance of the resonant circuit. The capacitance of the resonant circuit can be adjusted accordingly.

[0028] In a preferred embodiment, the resonant circuit is designed for load modulation by having an adjustable resistor. The resistor is, for example, an adjustable current source or an ohmic resistor. The load modulation is, for example, ASK load modulation according to the NFC standard.

[0029] Alternatively or additionally, the transmitter has an H-bridge and the control unit is designed to control the H-bridge in such a way that the resonant circuit is short-circuited in order to implement load modulation. The H-bridge is therefore essentially also an adjustable resistor, at least for the purpose of load modulation. The above statements initially apply to load modulation. One advantage over the use of a resistor in the resonant circuit is that the aforementioned H-bridge is usually already present and therefore no additional components need to be added to implement load modulation specifically for NFC communication. The load modulation is therefore implemented entirely with existing components. Only the control unit is additionally programmed accordingly. The H-bridge is in particular a part of the preferably analog transmitter.Energy is fed into the resonant circuit via the H-bridge, which then begins to oscillate at the transmit frequency. The resulting oscillation is then phase-modulated in the resonant circuit by controlling the H-bridge in phase.

[0030] The aforementioned digital chip of the hearing aid preferably implements digital signal processing. In contrast, the communication frontend described above is preferably purely analog. The digital chip processes the received and / or transmitted data and exchanges it with the communication frontend in baseband. The communication frontend then performs upconversion or downconversion to the currently selected carrier frequency, which is specified by the clock generator, as well as transmission or reception via the resonant circuit.

[0031] In summary, a few modifications to the existing architecture of a hearing aid can expand its functionality with regard to communication for data exchange. In particular, starting with a hearing aid with a communication frontend that is already configured for communication on an NFMI channel that is not an NFC channel, an additional option for communication via an NFC channel can be implemented using the same transceiver and the same resonant circuit. For this purpose, one or more of the following adjustments (described in detail above) are expediently made: • The clock generator for the transceiver is configured to be adjustable in order to switch the conversion between a baseband, on the one hand, and the transmit / receive frequency, on the other, between two different frequencies.

[0032] • the resonance frequency of the resonance circuit is adjustable,

[0033] • a power detector is used to determine when to switch between the two communication channels (at least in one direction),

[0034] • load modulation is realized, e.g. directly in the resonance circuit or in the transceiver,

[0035] • a control unit is designed to carry out one or more of the settings mentioned.

[0036] Any lower layers (e.g. “physical layer”) and / or upper layers (e.g. “protocol layer”) of the NFC channel are implemented in particular in the digital chip and are then combined with corresponding algorithms for the NFMI channel integrated therein in a single digital chip and are implemented either as hardware or as software.

[0037] The method is generally a method for operating a hearing aid as described above. Within the scope of the method, the control unit switches the transceiver between the first and second communication channels as described, for selective communication on one of the two communication channels.

[0038] In the following, exemplary embodiments of the invention are explained in more detail with reference to a drawing. In each case, the following schematically show:

[0039] Fig. 1 a hearing aid and an additional device,

[0040] Fig. 2 a communication frontend and a control unit of the hearing aid,

[0041] Fig. 3 shows a frequency spectrum of a received signal, Fig. 4 shows a control sequence during operation of the hearing aid.

[0042] Fig. 1 shows an embodiment of a hearing aid 2 according to the invention, also showing an additional device 4 (not to scale). The hearing aid 2 has a communications front end 6, an embodiment of which is shown in Fig. 2. The communications front end 6 has a resonant circuit 8 and a transceiver 10 for communication via electromagnetic induction. Communication here refers to the transmission and / or reception of electromagnetic signals containing data—in short, data exchange.

[0043] Resonant circuit 8 is connected to transceiver 10 and is used to transmit and receive corresponding signals during communication. In Fig. 2, resonant circuit 8 is an oscillating circuit with an inductance 12 and a capacitor 14, which define a resonant frequency of resonant circuit 8. In communication via electromagnetic induction, inductance 12 serves as an antenna, and the resonant frequency is a carrier frequency of the signals during communication.

[0044] The transceiver 10 has a transmitter 16 and a receiver 18. The transmitter 18 serves to convert a digital signal, which is generated by the hearing aid 2 and contains data to be transmitted, into a transmission signal, which is then output by the resonant circuit 8. Similarly, the receiver 18 serves to convert a reception signal, which is received by the hearing aid 2 via the resonant circuit 8 and contains data to be received, into a digital signal, which is then or can be further processed by the hearing aid 2. The digital signal is present here in a baseband 20. The transmission signal and the reception signal are present analogously at a reception frequency and transmission frequency, respectively, which are identical in this case.

[0045] In the hearing aid 2 described here, the transceiver 10 and optionally also the resonance circuit 8 are switchable between a first communication channel 22 at a first frequency f1 and a second communication channel 24 at a second frequency f2. The first and second frequencies f1, f2 are carrier frequencies of the two communication channels 22, 24 and thus also define the transmission frequency and the reception frequency.

[0046] The hearing aid 2 additionally has a control unit 26, which is part of a digital chip 28 of the hearing aid 2. In Fig. 2, the control unit 26 is part of the communication front end 6, or alternatively simply connected thereto. The control unit 26 is designed to switch the transceiver 10 between the first and the second communication channel 22, 24, for selective communication on one of the two communication channels 22, 24, i.e. at one of the two frequencies f1, f2. This enables the hearing aid 2 to at least receive and also send corresponding signals and thus data on two different communication channels 22, 24 by means of the same communication front end 6 and by means of the same transceiver 10. However, simultaneous communication on both communication channels 22, 24 is not possible in the present case.

[0047] In the embodiment shown here, the hearing aid 2 additionally has an input transducer 30 (here: microphone), a signal processor 32, and an output transducer 34 (here: receiver). The hearing aid 2 is assigned to a single user and is used solely by that user. The hearing aid 2 also serves to supply a hearing-impaired user and to compensate for the user's hearing loss. For this purpose, the input transducer 30 generates an input signal, which is fed to the signal processor 32. The signal processor 32 is part of the digital chip 28. The signal processor 32 modifies the input signal and thereby generates an output signal. To compensate for the hearing loss, the input signal is amplified with a frequency-dependent gain factor, for example, according to an audiogram of the user. The output signal is finally output to the user via the output transducer 34.In the embodiment shown here, the first communication channel 22 is an NFC channel and the second communication channel 24 is a different NFMI channel. In this way, the transceiver 10 is a combined NFC and NFMI transceiver. The NFMI channel referred to here does not correspond to the NFC standard, i.e., it is not simply an alternative NFC channel. In this case, the first frequency f1 is 13.56 MHz and the second frequency f2 is 10.6 MHz, so that the first frequency f1 is suitable for communication according to the NFC standard and the second frequency f2 for another, different NFMI communication, e.g., according to a manufacturer's own or proprietary specification. However, the frequencies f1 and f2 can also have other values.

[0048] The two communication channels 22, 24 are used here for communication between different devices, i.e. one communication channel 22 is not merely a substitute for the other communication channel 24, but enables a different connection. In the exemplary embodiment in Fig. 1, the hearing aid 2 is a binaural hearing aid with two individual devices 36 which are used by the same user. During intended use, one of the individual devices 36 is worn by the user on the left side of the head and the other individual device 36 on the opposite, right side of the head. One of the two communication channels 22, 24, here the NFMI channel 24, is designed for unidirectional or bidirectional communication between the two individual devices 36.The other of the two communication channels 22, 24, here the NFC channel 22, is then not used for communication between the individual devices 36, but for communication with the additional device 4 separately from the hearing aid 2. In this case, communication with the additional device 4 takes place either from both individual devices 36 or only from one of the individual devices 36. In Fig. 1, both individual devices 36 are equipped with a digital chip 28 and a communication frontend 6 as shown in Fig. 2 and are designed accordingly to communicate independently of one another with the additional device 4 via the communication channel 22. In principle, it is also conceivable that when communicating with the additional device 4, one individual device 36 serves as a relay for the other individual device 36. The additional device 4 is, for example, a smartphone, tablet, television, computer or the like. Thus, the communication channel 24 in Fig. 1 is used for internal communication, i.e.for communication between the individual devices 36, and the other communication channel 22 is used for external communication, ie for communication between the hearing aid 2 and the independent additional device 4.

[0049] The transceiver 10 is adjustable such that a signal is or can be received and / or transmitted either at the first frequency f1 or at the second frequency f2. For this purpose, the receiver 18 and the transmitter 16 are controlled accordingly, and a receive frequency of the receiver 18 or a transmit frequency of the transmitter 16 is set such that reception and / or transmission takes place optionally on the first or the second frequency f1, f2. For this purpose, the communications front end 6 in Fig. 2 has an adjustable clock generator 38 for specifying a clock T (also: clock rate, clock frequency) for the transceiver 10. The clock generator 38 is connected to the receiver 18 and the transmitter 16 such that the clock f is passed on to them accordingly. The clock f determines the receive frequency and the transmit frequency.The control unit 26 is then configured to adjust the clock rate f of the clock generator 38 to switch the transceiver 10, namely to switch the clock rate f between two different clock rates. By switching the clock generator 38, the first or second communication channel 22, 24 is used, depending on the setting.

[0050] In one possible embodiment, the clock f is switchable between the first frequency f1 and the second frequency f2. The receiver 18 thus uses the clock f to down-convert the received signal from its carrier frequency to the baseband 20. Conversely, the transmitter 16 uses the clock f to up-convert the transmitted signal from the baseband 20 to the carrier frequency. Alternatively, an embodiment is also possible in which, for one of the communication channels 22, 24, its frequency f1, f2 is not exactly matched, but in which the clock f is switchable between one of the two frequencies f1, f2 and a third frequency f3, which is so close to the other of the two frequencies f1, f2 that a sideband S to this other frequency f3 lies within a received frequency band B of the transceiver 10. This is shown in Fig.3, which shows, by way of example, the frequency spectrum of a signal (more precisely, the received signal at the hearing aid 2) during communication via the NFC channel 22. As can be seen, the data lies in the sideband S to the carrier frequency f1, and it is sufficient to receive only a corresponding frequency range on one side of the carrier frequency f1. During communication via the first communication channel 22, the sidebands S to the left and right of the carrier frequency f1 arise in the signal. Accordingly, it is sufficient to set the clock f and thus the receive frequency of the receiver 18 to a different frequency f3 such that this lies on one side of the carrier frequency f1, and the receive frequency band B, which lies around the receive frequency, then only covers one of the two sidebands S. The receive frequency and the receive frequency band B depend on a subcarrier frequency (e.g., 848 kHz according to the NFC standard).The reception frequency is the sum or difference of the carrier frequency (here the first frequency f1) and the subcarrier frequency. A possible second frequency f2 is also shown as an example in Fig. 3.

[0051] Since both communication channels 22, 24 cannot be used at the same time, in the embodiment shown here, one of the two communication channels 22, 24 is a standard channel, in this case the NFMI channel 24, and the other of the two communication channels 22, 24 is a demand channel, in this case the NFC channel 22. The standard channel is set and used by default, whereas the demand channel is only used when needed, when a signal is to be sent or received on this communication channel. This is shown as an example in Fig. 4, which indicates, as a function of time t, which communication channel 22, 24 is currently active and which frequency f1, f2 is currently set (In Fig. 3 it is assumed that switching takes place between the first and second frequencies f1, f2 and that no frequency f3 is used instead of one of the frequencies f1, f2). Fig.4 also shows an embodiment of the method according to the invention, in which the control unit 26 switches the transceiver 10 between the first and the second communication channel 22, 24, for selective communication on one of these two communication channels 22, 24.

[0052] In the embodiment shown here, the communications frontend 6 has a power detector 40 for measuring power at the frequency of the demand channel (here the first frequency f1), and the control unit 26 is designed to switch the transceiver 10 from the standard channel to the demand channel if the power detector 40 measures a power above a predetermined threshold at the frequency of the demand channel. The transceiver 10 is therefore switched from the standard channel to the demand channel precisely when a signal is received on the demand channel. For this purpose, the power detector 40 is specifically tuned to the frequency of the demand channel (here 13.56 MHz of the NFC channel 22) and connected to the resonant circuit 8 in order to receive the received signal from it and to measure the power at the frequency of the demand channel therein.If this power exceeds the specified threshold, the transceiver 10 is switched to the demand channel, as shown in Fig. 4.

[0053] As can also be seen in Fig. 4, in the present case the control unit 26 is also designed to switch the transceiver 10 back from the demand channel to the standard channel after a predetermined time interval has elapsed (so-called “timeout”) or - as shown here - after communication via the demand channel has been completed, which is detected by the control unit 26.

[0054] The resonant circuit 8 does not necessarily have to be adjusted, but if necessary supplies a correspondingly attenuated signal at at least one of the two frequencies f1, f2, with which communication is still possible. In the exemplary embodiment according to Fig. 2, however, the resonant circuit 8 has an adjustable resonant frequency and the control unit 26 is designed to set the frequency f1, f2 of the currently used communication channel 22, 24 as the resonant frequency of the resonant circuit 8. Analogous to the switching of the transceiver 10 depending on the currently used frequency, the resonant circuit 8 is then also switched accordingly in order to realize optimal transmission and reception power at the frequency f1, f2 of the respective communication channel 22, 24. In the embodiment shown here, the resonant frequency is set by adjusting the capacitance 14.

[0055] In the embodiment shown in Fig. 2, the resonant circuit 8 is configured for load modulation by having an adjustable resistor 42. The load modulation is, for example, an ASK load modulation according to the NFC standard. In an alternative embodiment not shown here, the transmitter 16 has an H-bridge, and the control unit 26 is configured to control this H-bridge such that the resonant circuit is short-circuited in order to implement the aforementioned load modulation.

[0056] Digital signal processing is implemented in the present case with the aforementioned digital chip 28 of the hearing aid 2. In contrast, the communication frontend 6 described here as an example is purely analog. However, other configurations are also possible. The digital chip 28 processes the received and / or transmitted data and exchanges it with the communication frontend 6 in the baseband 20. The communication frontend 6 then performs the upconversion or downconversion to the currently selected carrier frequency f1, f2, which is specified by the clock generator 38, as well as the transmission or reception via the resonant circuit 8.

[0057] List of reference symbols

[0058] 2 hearing aids

[0059] 4 Additional device

[0060] 6 Communication frontend

[0061] 8 Resonance circuit

[0062] 10 transceivers

[0063] 12 Inductance

[0064] 14 capacity

[0065] 16 transmitters

[0066] 18 receivers

[0067] 20 Baseband

[0068] 22 first communication channel (NFC channel)

[0069] 24 second communication channel (NFMI channel)

[0070] 26 Control unit

[0071] 28 digital chip

[0072] 30 input converters

[0073] 32 Signal processing

[0074] 34 output converters

[0075] 36 single devices

[0076] 38 clocks

[0077] 40 Power detector

[0078] 42 Resistance

[0079] B Receive frequency band f Clock f1 first frequency (carrier frequency) f2 second frequency (carrier frequency) f3 third frequency

[0080] 5 Sideband t Time

Claims

Hearing aid claims (2), - which has a control unit (26), - which has a communication front end (6) with a resonant circuit (8) and a transceiver (10) for communication by means of electromagnetic induction, - wherein the transceiver (10) is switchable between a first communication channel (22) at a first frequency (f1) and a second communication channel (24) at a second frequency (f2), - wherein the control unit (26) is designed to switch the transceiver (10) between the first and the second communication channel (22, 24) for selective communication on one of the two communication channels (22, 24). Hearing aid (2) according to claim 1, wherein the first communication channel (22) is an NFC channel and the second communication channel (24) is a different NFMI channel. Hearing aid (2) according to claim 1 or 2, wherein the first frequency (f1) is 13.56 MHz and the second frequency (f2) is 10.6 MHz. Hearing aid (2) according to one of claims 1 to 3, wherein it is a binaural hearing aid, with two individual devices (36), wherein one of the two communication channels (22, 24) is designed for communication between the two individual devices (36).Hearing aid (2) according to one of claims 1 to 4, wherein the communication front end (6) has an adjustable clock generator (38) for specifying a clock rate (f) for the transceiver (10), wherein the control unit (26) is designed to set the clock rate (f) of the clock generator (38) for switching the transceiver (10). Hearing aid (2) according to claim 5, wherein the clock (f) is switchable between the first frequency (f1) and the second frequency (f2). Hearing aid (2) according to claim 5, wherein the clock (f) is switchable between one of the two frequencies (f1, f2) and a third frequency (f3) which is so close to the other of the two frequencies (f1, f2) that a sideband (S) to this other frequency (f1, f2) lies within a reception frequency band (B) of the transceiver (10).Hearing aid (2) according to one of claims 1 to 7, wherein one of the two communication channels (22, 24) is a standard channel and the other of the two communication channels (22, 24) is a demand channel, wherein the communication front end (6) has a power detector (40) for measuring power at the frequency (f1, f2) of the demand channel, wherein the control unit (26) is designed to switch the transceiver (10) from the standard channel to the demand channel if a power above a predetermined threshold value is measured with the power detector (40) at the frequency (f1, f2) of the demand channel. Hearing aid (2) according to claim 8, wherein the control unit (26) is designed to switch the transceiver (10) back from the demand channel to the standard channel after a predetermined time interval has elapsed or after communication via the demand channel has been completed.Hearing aid (2) according to one of claims 1 to 9, wherein the resonance circuit (8) has an adjustable resonance frequency. wherein the control unit (26) is configured to set the frequency (f1, f2) of the currently used communication channel (22, 24) as the resonant frequency of the resonant circuit (8). Hearing aid (2) according to one of claims 1 to 10, wherein the resonant circuit (8) is configured for load modulation in that the resonant circuit (8) has an adjustable resistor (42). Hearing aid (2) according to one of claims 1 to 11, wherein the transceiver (10) has a transmitter (16) which has an H-bridge, wherein the control unit (26) is configured to control the H-bridge such that the resonant circuit (8) is short-circuited in order to realize load modulation. Hearing aid (2) according to one of claims 1 to 12, wherein the first frequency (f1) and the second frequency (f2) are carrier frequencies of the two communication channels (22, 24). Method for operating a hearing aid (2), - wherein the hearing aid (2) has a communication front end (6) with a resonance circuit (8) and a transceiver (10) for communication by means of electromagnetic induction, - wherein the transceiver (10) is switchable between a first communication channel (22) at a first frequency (f1) and a second communication channel (24) at a second frequency (f2), - wherein the hearing aid (2) has a control unit (26) which switches the transceiver (10) between the first and the second communication channel (22, 24) for selective communication on one of the two communication channels (22,

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