Hearing equipment

Abstract

The present invention relates to a hearing device (2), particularly a hearing aid, having a transmitter circuit (24) for transmitting wireless signals, wherein the transmitter circuit (24) has an electrical oscillation circuit (28) having at least one controllable semiconductor switch (34, 34a, 34b) and at least one capacitor (32, 32a, 32b) and a transmitter coil (30), and wherein at least one semiconductor switch (34, 34a, 34b) is controlled by a pulse phase modulator (36).

Description

Technical Field

[0001] This invention relates to a hearing device, particularly a hearing aid, having a transmitter circuit for transmitting wireless signals. Furthermore, this invention relates to a method for operating such a hearing device. Background Technology

[0002] Hearing assistive devices are portable hearing aids (hearing devices) designed for individuals with hearing impairments or hearing loss. To meet diverse individual needs, hearing assistive devices are available in various structural forms, such as behind-the-ear (HdO) hearing aids. Hearing devices with an external earpiece (RIC: receiver in the canal) and in-the-ear hearing devices (IdO, For example, there are also external hearing aids. Or in-ear hearing devices (ITE: In-The-Ear, CIC: Completely-In-Channel, IIC: Invisible-In-The-Channel). These exemplary hearing devices are worn on the outer ear or in the ear canal of the user. However, bone conduction hearing aids, implantable or tactile hearing aids are also available on the market. In these cases, the damaged hearing is stimulated mechanically or electrically.

[0003] Such hearing devices typically consist of an input converter, an amplifier, and an output converter as basic components. The input converter is usually an electroacoustic converter, such as a microphone and / or an electromagnetic receiver, such as an induction coil or a (radio frequency, i.e., RF) antenna. The output converter is usually implemented as an electroacoustic converter, such as a miniature loudspeaker (earpiece), or as an electromechanical converter, such as a bone conduction earpiece. The amplifier is usually integrated into the signal processing unit. Power is typically supplied by a battery or a rechargeable battery.

[0004] In so-called binaural hearing aids, a user wears two such hearing devices, with a communication or signal connection between them, also known as ear-to-ear or ear-to-ear (e2e) communication. During operation, the hearing devices in the right and left ears exchange data, possibly large amounts of data and / or audio signals, wirelessly, for example. The exchanged data and information allow the hearing devices to adapt particularly effectively to the corresponding acoustic environment. This results in a particularly realistic surround sound experience for the user and improved speech understanding even in noisy environments. Furthermore, it enables features and functions such as narrow focus or CROS (Contralateral Routing of Signal) to be implemented.

[0005] Because hearing devices have limited power sources, e2e signal transmission needs to be performed in a way that conserves as much power as possible to achieve several days of battery life in active e2e communication. Typically, the e2e communication system is implemented as a magnetic induction connection, consisting of analog and digital transmitters, two coils serving as transmitting and receiving antennas, and analog and digital receivers. Here, the transmitter circuitry of the communication system is crucial in terms of battery consumption.

[0006] During signal transmission, a carrier wave is typically used to modulate the useful signal to be transmitted, enabling high-frequency transmission of a low-frequency useful signal. At the receiving end, demodulation is used to recover the useful signal, or data and information. As a modulation format, constant envelope phase modulation is commonly used in binaural hearing aids due to energy conservation. Other transmitter topologies, such as IQ modulators, are unsuitable for low-power hearing aids due to their high power consumption.

[0007] The challenge in this design lies in building a power-efficient transmitter or transmitter that generates a signal with constant envelope phase modulation. Due to the limited space in hearing devices, the transmitter needs to be implemented in a compact manner that can be integrated into a customer-specific ASIC. In particular, as few external components as possible should be used. Furthermore, the generated transmitted signal must comply with regulatory requirements (e.g., spectral masking).

[0008] Such a transmitter or transmitter circuit may have an oscillation circuit and an energy supply circuit (energy feed circuit).

[0009] Different phases of the transmitter (TX) are achieved by changing the transmission frequency by detuning the oscillator circuit for a specific duration until the desired phase is reached. At least three different frequencies are used: the nominal transmission frequency (f0), a frequency below the transmission frequency used for negative phase shift (fm), and a frequency above the transmission frequency used for positive phase shift (fp). The transmitted signal is a continuous signal with a constant envelope curve.

[0010] The energy feed circuit is implemented, for example, as an H-bridge circuit. The energy feed circuit compensates for losses and feeds energy into the oscillator circuit at precise timing to maintain oscillations with a constant amplitude and desired frequency. The (feed-in) timing is synchronized with the oscillation. Summary of the Invention

[0011] The technical problem this invention aims to solve is to provide a particularly suitable hearing device, specifically one that achieves highly energy-efficient and compact e2e communication. Another technical problem this invention aims to solve is to provide a particularly suitable method for operating such a hearing device.

[0012] According to the present invention, in terms of hearing devices, the aforementioned technical problems are solved using the features of the present invention; in terms of methods, the aforementioned technical problems are solved using the features of the present invention. Advantageous design solutions and extensions are the subject of the following description. The advantages and designs listed regarding hearing devices can also be applied to methods, and vice versa.

[0013] Hearing devices are specifically designed as hearing aids and are preferably intended for users with hearing impairments (hearing device users). Here, the hearing device is configured to record sound signals from the environment and output them to the user. For this purpose, the hearing device has at least one electroacoustic input converter, particularly a microphone, and at least one electroacoustic output converter, such as an earpiece. During operation, the input converter records sound signals from the environment (noise, sounds, speech, etc.) and converts them into electrical input signals (acoustic data). An electrical output signal is generated from the electrical input signal by modifying the input signal in a signal processing device. The signal processing device is, for example, part of the hearing device. The input converter, output converter, and possibly the signal processing device are particularly housed within the housing of the hearing device. The housing is configured so that it can be worn by the user on the head and near the ears, for example, in the ear, on the ear, or behind the ear. The hearing device is preferably configured as a BTE hearing device, an ITO hearing device, or a RIC hearing device.

[0014] The hearing device has a transmitter or transmitter with transmitter circuitry for wireless signal transmission, particularly for e2e communication. The transmitter circuitry includes an oscillation circuit with at least one controllable semiconductor switch, at least one capacitor, and a transmitter or transmitting coil. According to the invention, at least one semiconductor switch is controlled by a pulse phase modulator. In other words, the transmitter circuitry according to the invention is configured and suitable for, and designed for, pulse phase modulation of the envelope curve of the transmitted signal. This results in a particularly suitable hearing device.

[0015] In a suitable extension, the oscillating circuit has two capacitors and two controllable semiconductor switches, each associated with a capacitor, and the transmitter coil is connected between the capacitors. Thus, the transmitter coil can be symmetrically controlled by the capacitors and the semiconductor switches.

[0016] In an advantageous embodiment, the output side of the bridge circuit is connected to the transmitter coil. In other words, the transmitter coil is connected between the two bridge branches. Here, the bridge circuit serves as a feed circuit, configured to feed loss energy (due to parasitic losses or radiated power) into the oscillating circuit to ensure a constant amplitude of the signal in the oscillating circuit or the transmitted signal. The bridge circuit is preferably implemented as an H-bridge circuit.

[0017] In a suitable design, a common timer is used to control the pulse phase modulator and the bridge circuit. In other words, the operating state of the bridge circuit and the pulse phase modulator is derived from the common timer or clock generator. This allows for the appropriate switching of the pulse phase modulator and the bridge circuit, while the oscillation circuit operates resonantly at the desired transmission frequency without monitoring the regulating voltage in the capacitor or the current in the transmitter coil.

[0018] An additional or further aspect of the invention is that the hearing device is configured to be binaural and for this purpose has two individual devices, each having at least one input converter and at least one output converter, thereby configured to record ambient sound signals and output them to the user of the hearing device. Additionally, each individual device has a transmitter circuit as a wireless interface for data exchange between the two individual devices. Here, the individual devices are coupled or at least can be coupled to each other via the transmitter circuit using signal technology.

[0019] In the case of binaural hearing devices, the user wears two single devices on opposite sides of the head, with each single device associated with one ear. However, as an alternative to binaural hearing devices, monocular hearing devices with only one single device are also suitable. The description of monocular hearing devices can also be applied to binaural hearing devices, and vice versa.

[0020] The method according to the invention is configured and adapted for use and designed for operating the hearing device described above. For wireless signal transmission, the transmitter circuit generates a transmit signal (TX signal), wherein, according to the method, the transmitter coil is disconnected from the capacitor or each capacitor at a first time point, and wherein, when the desired phase of the oscillation circuit is reached, the transmitter coil is reconnected to the capacitor or each capacitor at a later second time point. In other words, according to the method, the oscillation circuit is stopped or halted at the first time point and restarted at the second time point, thereby causing a phase shift in the generated transmit signal. This allows the transmitter circuit to be switched between different phases (TX phases).

[0021] Therefore, the transmitter design according to the present invention modulates the phase of the transmitted signal by pausing the oscillation circuit for a period of time. This method has the advantage that the desired phase is reached almost immediately, but at least within one transmission cycle. In contrast, according to the prior art, phase shift is generated by frequency detuning of the oscillation circuit based on the desired phase step size and frequency (fm, fp), requiring multiple transmission cycles before reaching the desired TX phase.

[0022] Furthermore, this enables the realization of a pulse phase modulator with reduced complexity and particularly low cost, since only one frequency, the nominal transmit frequency (f0), is transmitted or sent. According to the invention, other transmit frequencies (fm, fp) are no longer required, thereby simplifying the transmitter circuitry. Moreover, there is no need to adjust these frequencies.

[0023] With regard to the method steps described below, an advantageous design for the hearing device is obtained in particular by configuring the hearing device for implementing one or more of these method steps. Specifically, the hearing device preferably has a controller (i.e., a control unit) coupled to the transmitter circuitry. Here, the controller may, for example, be part of the signal processing device of the hearing device.

[0024] Here, the controller is generally configured, through programming and / or circuitry, to perform the method according to the invention described above. Specifically, the controller is configured to control a pulse phase modulator and / or semiconductor switches, and, if necessary, a bridge circuit.

[0025] In a preferred design, the controller is formed at its core by a microcontroller having a processor and data storage, wherein the functions for performing the methods according to the invention are implemented in the form of operating software (firmware) via programming techniques, thereby automatically executing the methods (and interacting with the device user if necessary) within the microcontroller when the operating software is executed. Alternatively, within the scope of the invention, the controller may also be formed by non-programmable electronic components, such as application-specific integrated circuits (ASICs), wherein the functions for performing the methods according to the invention are implemented using circuitry techniques.

[0026] In a favorable extension scheme, the transmitter coil is disconnected from the capacitor or each capacitor when the capacitor or each capacitor is substantially fully charged. To achieve good power efficiency, especially when the current in the transmitter coil is zero and the charge in the capacitor reaches its maximum positive value, the oscillation circuit is stopped by disconnecting the transmitter coil from the capacitor.

[0027] Due to detuned oscillator circuitry or asymmetry in the transmitter circuitry, voltage spikes or unwanted artifacts may appear in the transmitted signal. To avoid or suppress such undesirable effects, a suitable implementation is configured to short-circuit the transmitter coil when it is disconnected from the capacitors or each capacitor. This short-circuits any remaining energy in the transmitter coil.

[0028] Using the method according to the invention, continuous transmission signals are not generated because the resonant circuit is stopped in the event of phase shift. This also leads to signal transmission outside the useful frequency band, which is typically higher than in continuous operation. To reduce these undesirable transmissions, in a preferred configuration of the method, the semiconductor switches, or each semiconductor switch, are controlled using a control signal from a pulse phase modulator, wherein the control signal has dithering noise. In other words, dithering is incorporated for controlling the semiconductor switches.

[0029] For example, the semiconductor switch is turned off when the associated capacitor reaches its maximum positive or negative voltage. Thus, during the sinusoidal transmitted signal (sine wave), two switching processes are implemented at 0° and 180°. Therefore, for a restart, for a given TX phase, a second time point can be selected, such that the TX phase begins with a positive half-wave, or the TX phase begins a half-wave earlier (i.e., a negative half-wave 180° earlier), or the TX phase begins a half-wave later (i.e., a negative half-wave 180° later). Here, it is preferable that the switching time of the semiconductor switch varies randomly (jitter) between these time points. This has the advantages of significantly reducing unwanted transmissions and equalizing the length of the transmitted TX phase.

[0030] During operation, the pulse phase modulator generates first-order sidelobes at f0 ± 1.5fs in the resulting transmitted signal, where f0 is the carrier frequency and fs is the modulation symbol rate. If the symbol rate is chosen to be very high to increase the data rate of the radio line, the sidelobes may no longer be within the permissible legal bandwidth limit, and therefore must be attenuated to the sidelobe level predetermined by the transmit mask.

[0031] For wireless signal transmission in hearing aids, it is desirable to minimize sidelobes as simply as possible to keep processing overhead and thus power consumption as low as possible. In a preferred design of the method, the symbol rate of the transmitted signal is switched between at least two symbol rate values. In other words, the symbol rate is not constant but varies between two or more symbol rates. Therefore, the transmitted signal is generated by the superposition of different symbol rates, thereby suppressing sidelobes. Here, for signal transmission or e2e communication, the sequence of symbol rate switching or changes is stored not only on the transmitter side but also on the receiver side. Attached Figure Description

[0032] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings. Wherein:

[0033] Figure 1 A schematic diagram of a binaural hearing device is provided.

[0034] Figure 2 A simplified oscillation circuit for the transmitter is shown in block diagram.

[0035] Figure 3 The transmitter circuit is shown in partial block diagram.

[0036] Figure 4 The pulse phase modulation of the transmitter circuit's transmitted signal is illustrated using time-coil current curves and five switching pulse curves.

[0037] Figure 5 The switch bounce is illustrated using two time-coil current plots.

[0038] Figure 6 The frequency-amplitude curve shows the spectrum of the transmitted signal.

[0039] Figure 7 The frequency-amplitude curves illustrate the spectra of two different symbol rates, and

[0040] Figure 8 The frequency-amplitude curve shows the spectrum of the transmitted signal generated by the two superimposed symbol rates.

[0041] Corresponding parts and parameters are always given the same reference numerals in all the figures. Detailed Implementation

[0042] Figure 1 The basic structure of the hearing device 2 according to the present invention is shown. In this embodiment, the hearing device 2 is implemented as a binaural hearing aid device having two hearing aids or single devices 4a, 4b coupled by signal technology. Here, the single devices 4a, 4b are exemplary designed as behind-the-ear hearing aids (HdO). The single devices 4a, 4b are coupled or can be coupled to each other by means of wireless signal connection or e2e communication 6.

[0043] The structure of single devices 4a and 4b will now be illustrated by way of example using single device 4a. Figure 1 As schematically shown, the single device 4a includes a device housing 8, and one or more microphones, also known as acoustic-to-electrical input converters 10, are mounted in the device housing 8. The input converter 10 records sound or acoustic signals from the surrounding environment of the hearing device 2 and converts them into electro-audio signals or acoustic data.

[0044] Acoustic data is transmitted to signal processing device 14 via line 12. Signal processing device 14, also arranged in device housing 10, processes the acoustic data. Signal processing device 14 generates an output signal based on the audio signal and guides the output signal to a speaker or earpiece 18 via line 16. Here, earpiece 18 is implemented as an electroacoustic output converter that converts the electrical output signal into an acoustic signal. In the HdO single device 4a, if necessary, the acoustic signal is transmitted to the eardrum of the hearing device user via a sound tube (not shown in detail) or an external earpiece, i.e., an earmold located in the ear canal. However, in the case of bone conduction earpieces, for example, an electromechanical output converter as earpiece 18 may also be conceivable.

[0045] The power supply for the single device 4a, especially the signal processing device 14, is provided by a battery 20 housed in the device housing 8.

[0046] Signal connection 6 is implemented, for example, as magnetic inductive coupling between single devices 4a and 4b. For this purpose, signal processing device 14 is directed to transmitter 22 via signal technology. Transmitter 22 is used to transmit wireless signals via signal connection 6.

[0047] The transmitter 22 has the following features: Figure 2 and 3 The transmitter circuit 24, described in detail, is used to generate a transmit signal 26 that is transmitted via signal connection 6.

[0048] exist Figure 2The diagram shows a schematically simplified illustration of the electrical oscillation circuit 28 of the transmitter circuit 24. The oscillation circuit 28 is implemented in particular as a parallel resonant circuit, and includes a transmitting or transmitting coil 30, a capacitor 32, and a semiconductor switch 34 implemented as a transistor, particularly a MOSFET (Metal-Oxid-Halble-Feldeffekt transistor). The semiconductor switch 34 is controlled here by a pulse phase modulator 36.

[0049] exist Figure 3 The transmitter circuit 24 is shown. Here, the oscillation circuit 28 has two capacitors 32a and 32b and two semiconductor switches 34a and 34b. The terminals of the transmitter coil 30 are contacted via capacitors 32a and 32b, respectively, with each capacitor associated with one of the semiconductor switches 34a and 34b. The semiconductor switches 34a and 34b are jointly controlled by a pulse phase modulator 36 and therefore switch substantially simultaneously. Furthermore, the terminals of the transmitter coil 30 are connected to a bridge circuit 38 connected in parallel with the oscillation circuit 28.

[0050] Bridge circuit 38 is implemented as an H-bridge circuit with two bridge branches 40, each having two semiconductor switches 42a, 42b, 42c, and 42d. Here, semiconductor switches 42a, 42b, 42c, and 42d are controlled by pulse width modulation. On one hand, bridge branches 40 are connected to the power supply voltage via potential connectors 44. On the other hand, bridge branches 40 are in contact with ground potential via a second potential connector 46. The corresponding coil ends of transmitter coil 30 can be connected to the power supply voltage or ground potential via semiconductor switches 42a, 42b, 42c, and 42d. For example, if semiconductor switch 42a is closed (conducted) and semiconductor switch 42b is open (not conducted), then the coil end coupled to capacitor 32a is connected to the potential of the power supply voltage. Correspondingly, when semiconductor switch 42b is open and semiconductor switch 42a is closed, transmitter coil 30 is in contact with ground potential.

[0051] Bridge circuit 38 is set up and configured to feed loss energy (due to parasitic loss or radiated power) into oscillator circuit 28 when transmitter 22 is running, so as to obtain a constant amplitude in oscillator circuit 28, and thus obtain a constant amplitude of transmitted signal 26.

[0052] The oscillation circuit 28 is started, stopped, or terminated using semiconductor switches 34a and 34b. The precise turn-off time of semiconductor switches 34a and 34b is crucial for the operation of the transmitter circuit 24. Semiconductor switches 34a and 34b are appropriately opened when all the energy of the oscillation circuit 28 is stored in capacitors 32a and 32b, and no residual energy remains in the transmitter coil 30. This ensures that the transmitter circuit 24 operates with maximum efficiency, as any remaining energy in the transmitter coil 30 is lost when semiconductor switches 34a and 34b are opened. This avoids voltage spikes (self-inductance) at the transmitter coil 30, which could lead to undesirable transmission or even damage to the transmitter circuit 24. However, these effects cannot be completely avoided due to possible asymmetry in the transmitter circuit 24 or detuning of the oscillation circuit 28. Therefore, when semiconductor switches 34a and 34b are opened, the transmitter coil 30 is short-circuited to short-circuit any remaining energy in the transmitter coil 30. When semiconductor switches 34a and 34b are open, a short circuit is made by means of individual switches or by means of corresponding control of bridge circuit 38, such as by means of activation of semiconductor switches 42b and 42d.

[0053] Preferably, the operating or switching states of the bridge circuit 38 and the pulse phase modulator 36 are derived from a common clock or time generator. This ensures the synchronous switching of semiconductor switches 34a, 34b, 42a, 42b, 42c, and 42d. This guarantees the correct switching timing, allowing the oscillation circuit 28 to operate resonantly at the desired transmission frequency f0 without needing to monitor the regulating voltage in capacitors 32a and 32b or the coil current Is in the transmitter coil 30. This eliminates the need for additional ammeters and / or voltmeters, thus ensuring a simple, low-cost, and compact structure for the transmitter circuit 24.

[0054] Figure 4 The graph includes three vertically overlapping sections: 48, 50, and 52.

[0055] A schematic time-coil current plot is shown in section 48, in which time t is plotted in the horizontal direction, i.e., along the horizontal axis (X-axis), and the coil current Is of the transmitter coil 30 is plotted along the vertical axis (Y-axis).

[0056] Section 50 illustrates the variation of the control signals for the pulse phase modulator 36 used for semiconductor switches 34a and 34b, while section 52 illustrates the control signals for semiconductor switches 42a, 42b, 42c, and 42d. A high signal level of the control signal closes the corresponding semiconductor switches 34a, 34b, 42a, 42b, 42c, and 42d, making them conduction-free; conversely, a low signal level of the control signal opens the corresponding semiconductor switches 34a, 34b, 42a, 42b, 42c, and 42d, making them non-conduction-free. Here, semiconductor switches 42a and 42c are opened, and semiconductor switches 42b and 42d are closed, while semiconductor switches 34a and 34b are opened to short-circuit the transmitter coil 30.

[0057] Section 48 schematically illustrates the modulation of the transmitted signal 26 according to the invention. Here, the transmitted signal 26 is shown as a sinusoidal signal. Section 48 shows five transmitter modes (TX samples) 54a, 54b, 54c, 54d, 54e for achieving different modulation phases. For example, here, each transmitter mode 54a, 54b, 54c, 54d, 54e is provided with five sine waves, wherein one sine wave is omitted in the case of a positive phase shift (counterclockwise rotation), which results in four sine waves in these cases.

[0058] In transmitter mode 54a, there is a 0° modulation phase, where the transmitted signal 26 has five sine waves. In transmitter mode 54b, there is a -90° phase shift, where the phase modulator 36 disconnects semiconductor switches 34a and 34b, causing the oscillation circuit 28 to briefly stop or pause until the desired phase of the sinusoidal signal is achieved. The subsequent transmitter mode 54c also has a -90° phase shift; however, only four sine waves with a pause corresponding to a +90° phase shift are provided to achieve a 0° phase or phase shift again in transmitter mode 54d (relative to transmitter mode 54a). During transmitter mode 54d, the oscillation circuit 28 is paused to achieve a +135° phase shift for transmitter mode 54e. Because a +135° phase is transmitted in transmitter mode 54e, a sinusoidal oscillation needs to be initiated before the actual symbol boundary to achieve the 135° phase. Here, the fourth transmitter mode 54d has only four sine waves (sine waves with a phase of 0°).

[0059] The pulse phase modulator 36 has the disadvantage that there is no continuous TX signal because it must be interrupted or stopped in the event of a phase shift. This also results in unwanted signal emissions outside the desired frequency band, which are typically higher than during continuous operation. To reduce these unwanted emissions, switching jitter is provided.

[0060] Next, using Figure 5 The switching jitter of the pulse phase modulator 36 is explained in more detail. By switching jitter, jitter noise is set for the control signals of semiconductor switches 34a and 34b.

[0061] Figure 5 The graph comprises two vertically overlapping sections 56 and 58. Sections 56 and 58 respectively show schematic time-coil current graphs, in which time t is plotted horizontally along the x-axis and the coil current Is of the transmitter coil 30 is plotted along the y-axis. Here, the time axis is divided into several phases.

[0062] Here, when capacitors 32a and 32b reach their maximum positive or negative voltage, semiconductor switches 34a and 34b are turned off. This corresponds to two switching processes during the sinusoidal wave at 0° and 180°. Here, in the differential structure of transmitter circuit 24, charge is exchanged between the two capacitors. Here and below, the switching position at 0° should be understood in particular as the state when capacitor 32a has its maximum voltage (fully charged) while the other capacitor 32b has no voltage. When capacitor 32b has its maximum voltage while capacitor 32a has no voltage, the other switching point at 180° is correspondingly reversed.

[0063] Therefore, in general, for a given TX phase, it is possible to have three different positions for restarting the oscillation circuit 28.

[0064] On one hand, the desired TX phase begins with a positive half-wave. This time point is... Figure 4 The figure is marked with reference numeral 60. In section 56, time point 60 corresponds to a TX phase of 135°, while in section 58, a TX phase of 337.5° is selected. The resulting signal change process is marked with reference numeral 62 in the figure.

[0065] As a second starting position, it can begin with a half-wave earlier than time point 60, that is, with a negative half-wave but 180° earlier in phase. This variation is shown in section 56, where the oscillation circuit 28 is activated at an even earlier time point 62, thereby generating signal change process 66. Starting from time point 60, signal change processes 62 and 66 have the same time-varying characteristics.

[0066] As a third starting position, it can begin with a half-wave later than time point 60, that is, with a negative half-wave but 180° later in phase. This variation is shown in section 58, where the oscillating circuit 28 is activated at a later time point 68, thus generating signal change process 70. From time point 68, signal change processes 62 and 66 have the same time change process. Appropriately, the turn-off time point is selected corresponding to the planned starting position. For starting with a positive half-wave at 0°, the oscillating circuit 28 needs to be stopped beforehand, so that all charge is stored in one of the capacitors 32a and 32b, for example, capacitor 32a. For starting with a negative half-wave at 180°, the oscillating circuit 28 needs to be stopped accordingly, so that charge is stored in the corresponding other capacitor, for example, capacitor 32b, so that the coil current Is can start with a negative half-wave.

[0067] It is preferable to randomly switch between these three start or switch positions, thereby significantly reducing unwanted transmissions and equalizing the length of the transmitted phases. This jittering or jitter noise can be achieved, for example, through the following pseudocode:

[0068]

[0069] Here, rand is a random number between zero (0) and one (1), where txPhase is the transceiver phase in the range between 0° and 360°. The switching position is denoted by startPosition, where the starting position with the positive half-wave without delay is called Default_pos, the starting position with the negative half-wave 180° earlier is called Dither_neg_early, and the starting position with the negative half-wave 180° later is called Dither_neg_late.

[0070] As an addition to or replacement for switching jitter, phase polarity jitter could also be considered. Here, the off-cycle is shortened by restarting the oscillation circuit 28 with a phase shift of 0° or 180°. Preferably, the oscillation circuit is started at 0° or 180° regardless of whether it was previously stopped at 0° or 180°. Therefore, the difference in polarity jitter compared to the previously described embodiment is that the previously described embodiment required a shutdown at 0° so that it could also be turned on again at 0°. With this improvement through the additional H-bridge, a shutdown at 180° is possible, but a re-enabling at 0° (and vice versa), thus shortening the off-cycle. Furthermore, spectral emission is reduced, and transmitted energy is increased. Here, the additional H-bridge connected between capacitors 32a, 32b and transmitter coil 30 allows the polarity of the coil current Is to be rotated or reversed, enabling the oscillation circuit 28 to restart with the opposite polarity, i.e., a phase shift of 180°. Thus, the maximum possible gap or pause of the stopped oscillation circuit 28 is reduced from a full sine wave to at most half a sine wave.

[0071] Another aspect of the proposed pulse phase modulator 36 is the possibility of achieving 1-bit amplitude control. Here, for example, the oscillation circuit 28 can be stopped not only until the desired TX phase is reached, but also for a longer period of time, allowing the "transmit" amplitude of the transmitted signal 26 to be zero. This can further improve the transmission spectrum. Furthermore, for example, by using a PSK transmitter (PSK: Phase Shift Keying), the performance of the entire communication system of the hearing device 2 is also improved.

[0072] Next, using Figures 6 to 8 This section explains in more detail how to reduce interference transmission of the transmitted signal 26 by superimposing multiple symbol rates.

[0073] Figures 6 to 8 The frequency-amplitude curves of the transmitted signal 26 after Fourier transform are shown. Here, the frequency f is plotted in megahertz (MHz) along the horizontal axis (X-axis), and the normalized amplitude A of the Fast Fourier Transform (FFT) is plotted in decibels (dB) along the vertical axis (Y-axis).

[0074] During operation, the pulse phase modulator 36 generates a relatively high first-order sidelobe 72 at f0 ± 1.5fs, where f0 is the carrier frequency or transmission frequency, and fs is the modulation symbol rate. If the symbol rate fs is chosen to be very high to increase the data rate of the radio line, the sidelobe 72 may no longer be within the permissible legal bandwidth limit, and therefore must be attenuated to the signal level predetermined by the transmit mask 74.

[0075] Figure 6 An example of a violation of transmit mask 74 according to European standard ETSI EN 300 330 V2.1.1 is shown. Here, the permissible modulation must be within a bandwidth of ±7.5% × f0, and the interference transmit levels to its left and right must be attenuated by approximately 15 dB.

[0076] To reduce these interference transmissions, the symbol rate fs of the transmitted signal 26 is configured to switch between at least two symbol rate values ​​fs1 and fs2. In other words, the symbol rate fs of the transmitted signal 26 is not constant, but varies back and forth between two or more symbol rates fs1 and fs2. This effectively generates two transmitted signals 26a and 26b. Figure 7 In this embodiment, the symbol rate fs1 is slightly lower than the symbol rate fs, and the symbol rate fs2 is slightly higher than the symbol rate fs. Preferably, the symbol rates fs1 and fs2 differ from the transmission frequency f0 by 20% or less. In this embodiment, the transmission frequency is approximately 3.28 MHz, where the symbol rate fs is approximately 281 kHz, the symbol rate fs1 is approximately 234 kHz, and the symbol rate fs2 is approximately 328 kHz. Therefore, the symbol rate fs1 is approximately 17% higher than fs, and the symbol rate fs2 is correspondingly approximately 17% lower than fs.

[0077] When the symbol rates fs1 and fs2 are frequently or rapidly switched, the transmit spectra 26a and 26b are smoothed out so that the combined spectrum 26' no longer violates the specified transmit mask 74. Figure 8 The resulting spectrum or transmitted signal 26' is shown, which is generated by superimposing different symbol rates fs1, fs2 or transmitted signals 26a, 26b. By superimposing different symbol rates fs1, fs2, sidelobes 72 are suppressed. Here, for signal connection 6 or e2e communication, the switching or changing sequence between symbol rates f1, f2 is stored not only on the transmitter side but also on the receiver side.

[0078] This invention is not limited to the embodiments described above. Rather, those skilled in the art can derive other variations of the invention without departing from its subject matter. Furthermore, in particular, all the individual features described in connection with the embodiments can be combined with each other in other ways without departing from the subject matter of the invention.

[0079] List of reference numerals

[0080] 2 Hearing equipment

[0081] 4a, 4b Single device

[0082] 6. Signal Connection

[0083] 8. Device housing

[0084] 10 Input Converter

[0085] Line 12

[0086] 14. Signal processing device

[0087] Line 16

[0088] 18. Handpiece

[0089] 20 batteries

[0090] 22 transmitters

[0091] 24. Transmitter Circuit

[0092] Signals are transmitted at 26, 26a, 26b, and 26'.

[0093] 28 Oscillating Circuit

[0094] 30 transmitter coils

[0095] 32, 32a, 32b capacitors

[0096] 34, 34a, 34b Semiconductor Switches

[0097] 36-Pulse Phase Modulator

[0098] 38-bridge circuit

[0099] 40 Bridge Branch Road

[0100] 42a, 42b, 42c, 42d Semiconductor Switches

[0101] 44, 46 Potential Connectors

[0102] Parts 48, 50, and 52

[0103] 54a, 54b, 54c, 54d, 54e transmitter modes

[0104] Parts 56 and 58

[0105] 60 time points

[0106] 62. Signal Change Process

[0107] 64 Time Points

[0108] 66. Signal Change Process

[0109] 68 Time Points

[0110] 70 Signal Change Process

[0111] 72 side lobes

[0112] 74 Launch Mask

[0113] f0 transmission frequency

[0114] Is coil current

[0115] t time

[0116] f frequency

[0117] symbol rates of fs, fs1, and fs2

Claims

1. A hearing device (2) having a transmitter circuit (24) for transmitting wireless signals, the transmitter circuit generating transmission signals (26, 26a, 26b, 26'). - wherein, The transmitter circuit (24) has an electrical oscillation circuit (28), a feed circuit for feeding lost energy into the oscillation circuit (28), and a pulse phase modulator (36) for pulse phase modulation of the transmitted signals (26, 26a, 26b, 26'). - The oscillation circuit (28) has at least one controllable semiconductor switch (34, 34a, 34b) and at least one capacitor (32, 32a, 32b) connected in series, and a transmitter coil (30), and - wherein the at least one semiconductor switch (34, 34a, 34b) is controlled by the pulse phase modulator (36).

2. The hearing device (2) according to claim 1. Its features are, The oscillation circuit (28) has two capacitors (32a, 32b) and two controllable semiconductor switches (34a, 34b), wherein the semiconductor switches (34a, 34b) are correspondingly associated with the capacitors (32a, 32b), and wherein the transmitter coil (30) is connected between the capacitors (32a, 32b).

3. The hearing device (2) according to claim 1. Its features are, The transmitter coil (30) is connected to the bridge circuit (38).

4. The hearing device (2) according to claim 3. Its features are, The pulse phase modulator (36) and the bridge circuit (38) are controlled by a common timer.

5. The hearing device (2) according to any one of claims 1 to 4, wherein, The hearing device (2) is configured to be binaural and for this purpose has two single devices (4a, 4b), each of which has a transmitter circuit (28), and wherein the single devices (4a, 4b) are coupled via the transmitter circuit (28) by signal technology.

6. A method for operating the hearing device (2) according to any one of claims 1 to 5, wherein, In order to transmit wireless signals, the transmitter circuit (28) generates transmit signals (26, 26a, 26b, 26'), wherein the transmitter coil (30) is disconnected from each capacitor (32, 32a, 32b) at a first time point, and wherein the transmitter coil (30) is reconnected to each capacitor (32, 32a, 32b) at a later second time point (60, 64, 68) when the desired phase of the oscillation circuit (28) is reached.

7. The method according to claim 6, Its features are, When each capacitor (32, 32a, 32b) is fully charged, the transmitter coil (30) is disconnected from each capacitor (32, 32a, 32b).

8. The method according to claim 6, Its features are, When the transmitter coil (30) is disconnected from each capacitor (32, 32a, 32b), the transmitter coil (30) is short-circuited.

9. The method according to any one of claims 6 to 8, Its features are, Each semiconductor switch (34, 34a, 34b) is controlled by a control signal from a pulse phase modulator (36), wherein the control signal has jitter noise.

10. The method according to any one of claims 6 to 8, Its features are, Switch the symbol rate (fs1, fs2) of the transmitted signal (26') between at least two symbol rate values.

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