Method for operating a hearing device and hearing device

Abstract

The hearing device (2) has: a digital signal processing unit (4); a first electrical component, in particular a loudspeaker (6); a first electrical component, in particular a microphone (12), the first electrical component being controlled by the signal processing unit (4) via two electrical strands, respectively referred to as interference lines (10A, 10B), and the second electrical component being connected to an electrical connection line, respectively referred to as a receiving line (12), the digital control signals (SA, SB) being transmitted during operation via each interference line (10A, 10B). In order to reduce or in particular avoid interference effects, the two control signals (SA, SB) fed by the signal processing unit (4) into the interference lines (10A, 10B) are modulated in such a way that a differential signal (D) of the two control signals (SA, SB) applied to the first electrical component is designed as a bipolar control signal, according to the invention, the bipolar control signals are alternated between exactly two voltage values, and furthermore, the common-mode signal (C) formed by the two control signals (SA, SB) is constant.

Description

Technical Field

[0001] The invention relates to a method for operating a hearing instrument and to a hearing instrument. Background Art

[0002] Hearing devices are, in particular, hearing aids which are intended to compensate for the hearing loss of hearing-impaired persons.

[0003] Such hearing aids and hearing devices usually have a digital signal processing unit with an amplifier component, via which a receiver is controlled in particular. The receiver is usually designed as an electrodynamic loudspeaker. The receiver is usually connected to the amplifier component of the signal processing unit via a two-wire connecting line, via which high-frequency digital and modulated control signals are transmitted during operation.

[0004] When the receiver is designed as an electrodynamic loudspeaker, two control signals are applied to the coil of the receiver. In particular for energy saving reasons, the control signals are modulated (pulse width modulation or pulse density modulation) so that three different voltage values ​​(-1, 0, +1) are present at the receiver.

[0005] Hearing instruments usually have an input transducer, in particular a microphone, which converts acoustic sound signals into electrical signals, which are further processed by a signal processing unit and transmitted to a receiver as conditioned output signals in the form of two control signals.

[0006] It is also known to design hearing devices with a microphone arranged in the pinna. This is also referred to as the pinna microphone below. It is used to produce the so-called pinna effect. The pinna microphone is arranged in the pinna and is oriented backwards when worn. Such microphones are usually analog microphones, which are connected to a signal processing unit via a single connecting line for transmitting an analog received signal.

[0007] In particular in the case of RIC (receiver in the ear canal) hearing devices, this single connecting line is laid together with a two-wire control line for the receiver, for example in a common tube.

[0008] Furthermore, in particular analog sensors may be provided, for example temperature sensors or pressure sensors.

[0009] Due to the compact design of hearing instruments, there is often the problem of interference signals being transmitted between the different lines due to coupling effects. In particular, the two control lines leading to the receiver act as interference sources. Signals transmitted via the connecting lines, for example to the auricle microphone, are very sensitive to interference. Various measures are known to avoid such signal interference, such as shielding, laying the various lines as far apart as possible in space and / or twisting the lines. Summary of the invention

[0010] The technical problem to be solved by the present invention is to avoid interference in signal transmission.

[0011] This object is achieved according to the invention by a method for operating a hearing instrument having the features of claim 1 and a hearing instrument having the features of claim 11 .

[0012] The advantages and preferred embodiments described for the method can also be transferred to the hearing instrument and vice versa.

[0013] The hearing device is especially a hearing aid. The hearing device usually has: a digital signal processing unit, a first electrical component, especially a receiver, especially an electric speaker, and a second electrical component, especially a microphone. The first electrical component is controlled by the signal processing unit through two wire strands of a double-strand control line, respectively called interference wires, and the second electrical component is connected to an electrical connection wire called a receiving wire. During operation, a digital control signal is transmitted through each interference wire respectively. Due to parasitic effects, especially parasitic capacitance, interference signals are coupled from each interference wire to the receiving wire. In order to keep the influence on the signal transmitted through the receiving wire small or avoid it, the signal processing unit is now designed to modulate the control signal fed into the two interference wires during operation, that is, the differential signal of the two control signals applied to the first electrical component, that is, especially the receiver, is constructed as a bipolar control signal, which alternates between exactly two voltage values, and in addition, the common mode signal formed by the two control signals is constant. The common mode signal is formed by the average voltage of the voltage values ​​of the two control signals. The applied control signal is especially formed for the first electrical component, especially the supply voltage for the receiver.

[0014] As already mentioned, for reasons of energy consumption, the control signal is modulated in such a way that the control signal of the two control signals present at the receiver (differential signal) varies between three voltage levels -1, 0, + 1. However, a disadvantage of this modulation is that crosstalk effects constitute a particular problem in the case of long, closely arranged control lines, in particular in the case of pinna microphones.

[0015] In order to avoid this problem, it is now provided that the differential signal changes only between two voltage values, in particular between +1 and -1. This design is based on the consideration that due to the typical capacitive coupling effect, the two control signals are coupled into the receiving line and added there. In addition, the design is based on the consideration that due to the special modulation of the control signal, the common mode signal is constant and therefore does not generate crosstalk. Crosstalk only occurs when the common mode signal changes, as is the case with conventional modulation of the control signal and control of the receiver.

[0016] The basis of the present design is that a symmetrical, bipolar control signal is intentionally applied to the receiver so that the common-mode signal is constant in order to at least reduce the interference effects caused by crosstalk. The invention intentionally takes higher energy consumption into account.

[0017] The receiving line is usually connected to a signal processing unit for further processing of the signal transmitted via the receiving line. The signal processing unit evaluates the signal transmitted via the receiving line. In addition, as mentioned above, the signal processing unit is also used to generate a rectified output signal, which is preferably fed into the interference line in the form of two control signals.

[0018] When a bipolar control signal applied to an electrical component (i.e. a bipolar differential signal of two control signals applied to a first electrical component) is mentioned here, it is understood that the bipolar control signal changes back and forth between exactly two voltage values, specifically in particular between positive and negative voltage values ​​(+1 and -1). The voltage values ​​are in particular positive and negative voltage values ​​of a power source, for example a battery. The voltage values ​​are usually in the range of several volts (e.g. 1 V to 5 V).

[0019] In order to generate a bipolar control signal applied to the electrical component, the two control signals are preferably phase-opposite, to be precise one control signal has a voltage value of +1 and the other control signal has a voltage value of 0. This ensures that the bipolar differential signal / control signal applied to the first component (receiver) only has the values ​​+1 and -1.

[0020] In particular, the receiving line is a so-called single-end line, in which the second component is connected only via a single signal strand for signal transmission. The receiving line is therefore - unlike the control line - not exactly a two-strand signal line.

[0021] In a preferred design, the second component is preferably an analog component which feeds an analog signal into the receiving line.

[0022] The second component is preferably a microphone, in particular a so-called pinna microphone.

[0023] The hearing device is therefore preferably a RIC hearing device (Receiver in Canal). The receiving cable is guided together with the two-wire control cable in the direction of the receiver, preferably in a common hose. The two-wire control cable and the (single-wire) receiving cable are thus guided closely side by side over a relatively long distance.

[0024] Alternatively or additionally, the second component is an, in particular, analog sensor, for example a temperature sensor or a pressure sensor.

[0025] The second component is preferably connected to an analog-digital converter via a receiving line, which converts the analog signal into a digital signal. The digital signal is then usually further processed by a digital signal processing unit.

[0026] The control signal is preferably generated by an amplifier component of the signal processing unit, which is in particular an H-bridge and / or a so-called class D amplifier. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The embodiments of the present invention are further described below with reference to the accompanying drawings. In the accompanying drawings:

[0028] FIG1 shows a highly simplified circuit diagram of a hearing device in a simplified block diagram;

[0029] FIG. 2 shows a combined graph of multiple signal curves, and

[0030] Figure 3 shows an H-bridge with a receiver connected. DETAILED DESCRIPTION

[0031] The hearing device 2 shown in simplified form in FIG. 1 is in particular a hearing aid which is configured to compensate for a user-specific hearing impairment. For this purpose, the hearing aid is configured and adjusted in a manner known per se so that in particular an amplification adapted to the user-specific hearing impairment, for example a frequency-dependent amplification, takes place. The hearing device 2 generally has a receiver / signal converter (not shown in the figure), for example a microphone, which generally converts the acoustic signal into a digital input signal and forwards it to a digital signal processing unit 4, in which the digital input signal is conditioned according to the user-specific settings, in particular amplified and sent on as a conditioned output signal to a receiver which is in particular designed as a loudspeaker 6.

[0032] The digital signal processing unit 4 comprises for this purpose, in particular, an amplifier component 8, which preferably has an H-bridge and / or is designed as a so-called class D amplifier. It is connected to the loudspeaker 6 via a two-wire control line 10, thus via two wires. These wires are referred to below as interference wires 10A, 10B.

[0033] The output signals processed by the control unit 4 are transmitted via the two-wire control line 10. For this purpose, the modulated (pulse width modulated or pulse density modulated) control signal S A , S B These control signals S A , S B The (modulated) pulse train thus respectively consists of a single positive voltage pulse with an amplitude of +1 (+1 denotes the voltage value of the applied supply voltage, for example a battery voltage).

[0034] Furthermore, the hearing instrument 2 has an auricle microphone 12 which is connected for voltage supply via a power supply line 14 on the one hand to a supply voltage 16 and via a ground line 18 on the other hand to a ground potential or ground potential 20 .

[0035] Furthermore, the pinna microphone 12 is connected to the signal processing unit 4, in particular to an analog-digital converter 24, via a reception line 22. In the exemplary embodiment, a filter 26, in particular a low-pass filter, is arranged upstream of the analog-digital converter 24.

[0036] The hearing device 2 is preferably a RIC hearing device. The hearing device has a main body with its own housing (not shown in detail here), wherein the main body is usually worn behind the ear. Several components of the hearing device 2, in particular the signal processing unit 4, are contained in the closed housing of the main body.

[0037] The double-stranded control line 10 and the receiving line 22 and usually also the power supply line 14 are guided together closely and especially in a common hose from the main body to the earpiece of the hearing device 2 remote from the main body, which earpiece is inserted into the ear, especially into the auricle or the ear canal of the user. In addition, usually the ground line 18 is also arranged together with the aforementioned lines and especially in a common hose (not shown). The earpiece has a loudspeaker 6. The line shown in dashed lines in FIG. 1 depicts the interface between the main body and the components arranged outside the main body.

[0038] During operation, acoustic signals are detected by the pinna microphone 12 and forwarded as analog (data) signals via the reception line 22 to the signal processing unit 4 .

[0039] The analog signal is particularly sensitive to interference signals due to the close proximity of the control line 10, which are caused by the control signal S on the two interference lines 10A, 10B. A , S B The coupling into the receiving line 22 is caused by parasitic effects.

[0040] To illustrate these parasitic effects, a parasitic capacitive coupling path 28 is shown in FIG1 . It is not a physical wired connection, but only a parasitic effect. For each control signal S A , S B , corresponding to the corresponding control signal S A , S B The interference signal is coupled into the receiving line 22 through these parasitic effects.

[0041] In order to reduce or avoid the interfering influence of these parasitic effects on the signal in the reception line 22, it is now provided that the control signal S is coupled by the signal processing unit 4, in particular by the amplifier component 8, to the two control lines 10A, 10B. A , S BThe total signal (control signal or voltage) applied to the loudspeaker 6 is modulated in this way, that is, it is designed to be a bipolar signal with only two voltage states +1 and -1, and the total signal is the two control signals S A , S B The differential signal D between them (see also Figure 2).

[0042] From the control signal S shown in FIG1 A , S B It can be seen from the pulse sequence that these control signals S A , S B have opposite phases. It should be understood here that when a control signal S B With a voltage value of 0, another control signal S A has a voltage value of +1 and vice versa.

[0043] At the same time, it is also achieved that the common mode signal C (see Figure 2) has a constant value, (S A +S B ) / 2=0.5. This is shown in Figure 1 by the total signal S sum express.

[0044] Due to the constant common mode signal C it is ensured that no interfering influences are coupled into the receive line 22 , since in the present configuration interfering influences on the (analog) data on the receive line only occur when the common mode signal changes.

[0045] Explanation of the different signal curves with reference to Figure 2:

[0046] First, in the first row, an analog signal A is shown, for example, as an oscillating wave. The analog signal A is represented by a digital signal. More specifically, the oscillating wave is formed by a control signal S A , S B Suitable pulse sequences are shown (rows 2 and 3).

[0047] These control signals S A , S B applied to the loudspeaker 6, thus defining its control signal or the voltage applied to it. It is determined by the differential voltage D = S A -S B is formed (row 4). It has voltage values ​​+1 and -1 alternately.

[0048] Furthermore, a common mode signal C having a constant signal level of a voltage value of 0.5 is shown in the fifth row of FIG. 2 .

[0049] 3 explains how to generate the control signal S by means of an H bridge as amplifier component 8 A , S BPulse sequence: It has a total of 4 switches S1-S4, which are connected to the supply voltage and the ground potential (GND) as shown in the figure. The supply voltage is especially the voltage of the battery of the hearing instrument 2. The supply voltage is represented by a plus sign (+) and the ground potential is represented by a minus sign (-). An interference line 10A is connected between the switch pair S1 and S2, and another interference line 10B is connected between the switch pair S3 and S4. Their ends are in turn connected to the loudspeaker 6, more precisely to its coil 30. The supply voltage is applied between the switches S1 and S3, and the switches S2 and S4 are each connected to the ground potential.

[0050] For the voltage state control signal S A =+1 and control signal S B =0, switches S1 and S4 are closed, while S2 and S3 are open (first switch position configuration). The differential signal D applied to the speaker 6, in particular to the coil 30, or the voltage applied to the coil is as follows:

[0051] D = S A -S B = 1–0 = +1

[0052] For the voltage state control signal S A = 0 and the control signal S B =+1, switches S2 and S3 are closed, while S1 and S4 are open (second switch position configuration). The differential signal D applied to the speaker 6, in particular to the coil 30, or the voltage applied to the coil is as follows:

[0053] D = S A -S B = 0–1 = -1

[0054] The pulse sequence shown in Figure 2 is obtained by appropriate control of switches S1-S4. The H-bridge is switched only between the two switch position configurations described above.

[0055] The specially designed control signal S A , S B The principle is not limited to the application example described here with the pinna microphone 12 and the RIC hearing device. As an alternative to the pinna microphone 12, the second component is, for example, an analog sensor, such as a temperature sensor or a pressure sensor. Instead of the RIC hearing device, other types of hearing devices are generally also possible, such as BTE (Behind The Ear) hearing devices.

[0056] Reference numerals list

[0057] 2 Hearing devices

[0058] 4Signal processing unit

[0059] 6 speakers

[0060] 8 Amplifier Parts

[0061] 10 Control Line

[0062] 10A, 10B interference line

[0063] 12 Ear Microphones

[0064] 14 Power cord

[0065] 16 Supply voltage

[0066] 18 ground wire

[0067] 20 Ground potential

[0068] 22 receiving lines

[0069] 24 analog-to-digital converters

[0070] 26 filters

[0071] 28 coupled lines

[0072] 30 coils

[0073] S A , S B Control Signal

[0074] S sum Total signal

[0075] AAnalog signal

[0076] D Differential Signaling

[0077] C common mode signal

Claims

1. A method for operating a hearing instrument (2), the hearing instrument having: a digital signal processing unit (4); a first electrical component, in particular a loudspeaker (6); and a second electrical component, in particular a microphone (12), wherein: The first electrical component is controlled by a signal processing unit (4) via two electrical lines, each referred to as an interference line (10A, 10B), and the second electrical component is connected to an electrical connection line, referred to as a receiving line (12), wherein during operation a digital control signal (S) is transmitted via each interference line (10A, 10B) A , S B ), characterized in that two control signals (S A , S B ) are modulated so that the two control signals (S A , S B ) is configured as a bipolar control signal, the bipolar control signal alternately switching between exactly two voltage values, and furthermore, the two control signals (S A , S B )The common-mode signal (C) formed is constant.

2. The method according to claim 1, wherein: The bipolar control signal switches between voltage values ​​of +1 and -1.

3. The method according to any one of the preceding claims, wherein: The control signal (S A , S B ) are in opposite phase, so that a control signal (S A ) has a voltage value of +1, and another control signal (S B ) has a voltage value of 0.

4. The method according to any one of the preceding claims, wherein: The receiving line (12) is a single-ended line.

5. The method according to any one of the preceding claims, wherein: The second component is an analog component that feeds an analog signal into a receiving line (12).

6. The method according to any one of the preceding claims, wherein: The second component is a microphone, in particular an auricle microphone (12).

7. The method according to any one of the preceding claims, wherein: The second component is the analog sensor.

8. The method according to any one of the preceding claims, wherein: The second component is connected to the analog-to-digital converter (24) of the signal processing unit (4) via a receiving line (12).

9. The method according to any one of the preceding claims, wherein: The control signal is generated by an amplifier component (8), in particular an H-bridge, of the signal processing unit (4).

10. The method according to any one of the preceding claims, wherein: The two wire strands are guided together with the receiving wire (12) and the hearing device (2) is in particular an RIC hearing device (2).

11. A hearing device (2), in particular a hearing aid device, comprising: - a digital signal processing unit (4), - a first electrical component, in particular a loudspeaker (6), - a second electrical component, in particular a microphone (12), -in, The first electrical component is connected to the signal processing unit (4) via two wire strands, respectively referred to as interference wires (10A, 10B), The signal processing unit (4) is designed to respectively transmit the control signal (S) via each interference line (10A, 10B) during operation. A ,S B ) is transmitted to the first component, - and among them, The second electrical component is connected to an electrical connection line, called a receiving line (12), characterized in that The signal processing unit (4) is designed to process the control signal (S) fed into the interference line (10A, 10B) during operation. A , S B ) are modulated so that the two control signals (S A , S B ) is configured as a bipolar control signal which alternates between exactly two voltage values ​​and is composed of two control signals (S A , S B )The common-mode signal formed is constant.

12. The hearing device (2) according to claim 11, wherein The signal processing unit (4) has an amplifier component (8), in particular an H-bridge, a control signal (S A , S B ) is generated by the H-bridge, - The signal processing unit (4) is designed so that the control signal (S A , S B ) are in opposite phases, so that one control signal has a voltage value of +1 and the other control signal has a voltage value of 0, - the signal processing unit (4) is designed so that the bipolar control signal changes between voltage values ​​+1 and -1, - the receiving line (12) is a single-ended line, The second component is an analog microphone, in particular an auricle microphone (12).

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