METHOD AND HEARING DEVICE FOR TRANSMITTING AN AUDIO SIGNAL FROM A TRANSMITTER TO A RECEIVER

Abstract

A method transmits an audio signal from a transmitter to a receiver and a hearing device, particularly a hearing aid, contains a communication facility which is provided and configured for transmitting and/or receiving an audio signal according to the method. A hearing device system has two hearing devices and is provided and configured to transmit audio signals between the two hearing devices by their communication facilities according to the method.

Claims

1. A method for transmitting an audio signal from a transmitter to a receiver, which comprises the steps of: dividing an input signal corresponding to the audio signal into a number of frequency channels for a particular time window, at a transmitter end; allocating a current channel value to each frequency channel at the transmitter end; dividing current channel values into a first current data record and a second current data record, at the transmitter end; generating a first forecast for the first current data record by means of a channel value preceding in time at the transmitter end; determining a first deviation between the first forecast and the first current data record at the transmitter end; generating a second forecast for the second current data record by means of the first current data record, at the transmitter end; determining a second deviation between the second forecast and the second current data record at the transmitter end; transmitting a first transmission value corresponding to the first deviation from the transmitter to the receiver; transmitting a second transmission value corresponding to the second deviation from the transmitter to the receiver; generating a first reconstructed data record by means of a reconstructed output signal preceding in time and the first transmission value, at a receiver end; generating a second reconstructed data record by means of the first reconstructed data record and the second transmission value at the receiver end; and combining the first reconstructed data record and the second reconstructed data record to form a reconstructed output signal at the receiver end.

2. The method according to claim 1, which further comprises: generating, at the transmitter end, the second forecast by means of the channel value preceding in time; and generating, at the receiver end, the second reconstructed data record by means of the reconstructed output signal preceding in time.

3. The method according to claim 1, wherein for generating the first forecast and the first reconstructed data record, a linear prediction is utilized and/or that, for generating the second forecast and the second reconstructed data record, the linear prediction is utilized.

4. The method according to claim 1, which further comprises dividing the input signal into the frequency channels by means of band pass filters.

5. The method according to claim 1, which further comprises performing at least one of: generating the first transmission value by means of quantization of the first deviation; or generating the second transmission value by means of quantization of the second deviation.

6. The method according to claim 5, wherein at the transmitter end, by means of the first and second transmission values, respectively, and the first forecast and the second forecast, respectively, a third reconstructed data record is generated which is utilized as the channel value preceding in time during a transmission following in time.

7. The method according to claim 5, which further comprises utilizing a vector quantization for the quantization.

8. The method according to claim 5, which further comprises utilizing a spherical logarithmic quantization for the quantization.

9. The method according to claim 1, which further comprises generating the first reconstructed data record by the further steps of: generating, by means of the first transmission value, a first auxiliary data record which corresponds to the first deviation; generating, by means of the reconstructed output signal preceding in time, a first auxiliary forecast which corresponds to the first forecast; and adding the first auxiliary data record to the first auxiliary forecast.

10. The method according to claim 1, wherein the second reconstructed data record is generated by the further steps of: generating, by means of the second transmission value, a second auxiliary data record which corresponds to the second deviation; generating, by means of the first reconstructed data record, a second auxiliary forecast which corresponds to the second forecast; and adding the second auxiliary data record to the second auxiliary forecast.

11. The method according to claim 1, wherein the first and/or second deviation is generated in that a difference between each said current channel value of the first current data record and of the second current data record, respectively, and an allocated prognostic value of the first and second forecast is generated for forming a difference value and difference values form the first and second deviation, respectively.

12. The method according to claim 1, which further comprises dividing the current channel values in halves between the first current data record and the second current data record.

13. A hearing device, comprising: a communication facility provided and configured for transmitting and/or receiving an audio signal according to a method according to claim 1.

14. A hearing device system, comprising two hearing devices each having a communication facility provided and configured for transmitting and/or receiving an audio signal according to a method according to claim 1, said hearing devices configured to transmit audio signals between said two hearing devices by means of said communication facility.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

[0045] FIG. 1 is an illustration diagrammatically showing a hearing device system having two hearing devices;

[0046] FIG. 2 is a flow chart showing a method for transmitting an audio signal between the two hearing devices;

[0047] FIG. 3 is a graph showing an input signal corresponding to the audio signal; and

[0048] FIGS. 4-6 are illustrations which in each case show data records partially.

DETAILED DESCRIPTION OF THE INVENTION

[0049] Parts corresponding to one another are provided with the same reference symbols in all figures.

[0050] Referring now to the figures of the drawings in detail and first, particularly to FIG. 1 thereof, there is shown a hearing device system 2 having two constructionally identical hearing aids 4, which hearing aids 4 are provided and configured to be worn behind the ear of a user. In other words, they are in each case behind-the-ear hearing aids which have an acoustic tube, not shown, which is introduced into the ear. Each hearing aid 4 contains a housing 6 which is made of a plastic material. Inside the housing 6, a microphone 8 having two electromechanical sound transducers 10 is arranged. By the two electromechanical sound transducers 10, it is possible to change a directional characteristic of the microphone 8 by changing an offset in time between the acoustic signals detected by the respective electromechanical sound transducer 10. The two electromechanical sound transducers 10 are coupled to a signal processing unit 12, which contains an amplifier circuit, with respect to signals. The signal processing unit 12 is formed by circuit elements such as, for example, electrical and/or electronic components.

[0051] Furthermore, a loudspeaker 14 is coupled to the signal processing unit 12 with respect to signals, by which loudspeaker audio signal 16 recorded by the microphones 8 and/or processed by the signal processing unit 12 are output as sound signals. These sound signals are conducted into the ear of a user of the hearing device system 2 by an acoustic tube not shown in detail.

[0052] Each of the hearing aids 4 also has a transmitter 18 and a receiver 20 by which an exchange of data signals 22 takes place between the two hearing aids 4. The exchange takes place, for example, by radio or inductively. Here, the signal processing unit 12, the transmitter 18 and the receiver 20 together form in each case essentially a communication facility 24. Due to the exchange of data signals 22 it is made possible to convey a spatial hearing sensation to the wearer of the hearing device system 2. In summary, the hearing device system 2 is equipped binaurally.

[0053] In FIG. 2, a method 26 is shown according to which the audio signals 16 are transmitted between the two hearing devices 4 by their respective communication facility 24. In a first operating step 28, the audio signal 16 is received by the hearing aid 4. In a subsequent second operating step 30, an input signal 32 is generated from this which in consequence corresponds to the audio signal 16 and which is shown by way of example in FIG. 3. For this purpose, the audio signal 16 is filtered, for example. Furthermore, the input signal 32 is subdivided into time windows 34 which have the same length in time which, for example, is equal to one millisecond. As soon as the last time window 34 in time is ended, this time window 34 is divided into a number of frequency channels 36 as shown, for example, in FIG. 4. To divide the input signal 32 into the individual frequency channels 36, bandpass filters (frequency pass filters) 38 are utilized which are present within the signal processing unit 16. To each of the frequency channels 36, a particular current channel value 40 is allocated. In summary, the input signal 32 is divided into the individual frequency channels 36 in the second operating step 30, and discretized by means of the allocation of the current channel value 40.

[0054] Furthermore, after the first operating step 16 is carried out by the transmitter 18, a third operating step 42 is carried out in which channel values 44 preceding in time are filled. These have been determined, for example, during a preceding pass of the method 26 or, if the method 26 has not yet been carried out, a standard value is utilized for this purpose. As well, a fourth operating step 46 is carried out at the receiver 20 in which a reconstructed audio signal 48 preceding in time is determined. This corresponds to the channel values 44 preceding in time and is determined in the same way as the channel values 44 preceding in time.

[0055] Furthermore, a fifth operating step 50 is carried out in which the number of current channel values 40 is divided into a first current data record 52 and a second current data record 54. In this context, the current channel values 40, which are allocated to an odd frequency channel 36, are allocated to the first data record 52 and the remaining current channel values 40 are allocated to the second current data record 54 so that the two current data records 52, 54 have essentially the same number of current channel values 40.

[0056] In a sixth operating step 56, a first forecast 58 is generated for the first current data record 52 by use of the channel values 44 preceding in time. To generate the first forecast 58, a linear prediction is utilized. In other words, a number of prognostic values 60 is generated, each of the prognostic values 60 being allocated to one of the current channel values 40 of the first current data record 52. For example, only the channel values 44 preceding in time, which are allocated to the time window 34 directly preceding in time, are utilized. In this context, for example, only the channel values 44 preceding in time, which are allocated to adjacent frequency channels 36, are used for generating the respective prognostic value 60 (“predicted value”).

[0057] In a subsequent seventh operating step 61, a first deviation 60 between the first forecast 58 and the first current data record 52 is generated for which the difference between each of the current channel values 40 of the first current data record 52 and each of the prognostic values 60 of the first forecast 62 is subtracted for generating a difference value. The number of prognostic values 60 and the number of difference values correspond to the number of current channel values 40 of the first current data record 52.

[0058] In a subsequent eighth operating step 64, a first transmission value 66 which corresponds to the first deviation 62 is generated by a spherically logarithmic quantization. The first transmission value 66 is in this case unidimensional. In other words, the unidimensional first transmission value 66 is allocated to the multidimensional first deviation 62. This value is transmitted by one of the data signals 22 to the receiver 20 of the remaining hearing aid 4. By means of the communication facility 24 of the hearing aid 4 having the receiver 20, a ninth operating step 68 is carried out which, by means of carrying out the inverse function corresponding to quantization, a first auxiliary data record 70 is generated which, in consequence, corresponds to the first deviation 62. By utilizing the reconstructed output signal 48 preceding in time, a first auxiliary forecast 72 also is generated likewise with prognostic values, using the same linear prediction as for the generation of the first forecast 58. Since the reconstructed output signal 48 preceding in time corresponds to the channel values 44 preceding in time, the first auxiliary forecast 72 corresponds to the first forecast 58. Furthermore, the first auxiliary data record 70 is added value by value to the first auxiliary forecast 72. The resultant data record is a first reconstructed data record 74 which, with the exception of any noise/disturbances induced due to the use of the spherically logarithmic quantization, corresponds to the first data record 52 which is present at the transmitter 18.

[0059] At the transmitter 18, a second forecast 78 is generated with a number of prognostic values 80 (“predicted value”) corresponding to the number of current channel values 44 of the second current data record 54 on the basis of the channel values 44 preceding in time and by using the current channel values 40 of the first current data record 52 by a linear prediction in a tenth operating step 76, wherein, for example, the channel values 44 of adjacent frequency channels 36 of the first current data record 52 and the respective value, preceding in time, of the same frequency band 36 are utilized for generating the prognostic value 80. In consequence, the second forecast 78 is generated by the channel values 44 preceding in time and the first current data record 52. In this context, each of the prognostic values 80 corresponds to one of the current channel values 44 of the second current data record 54. In a subsequent eleventh operating step 82, a second deviation 84 between the second forecast 78 and the second current data record 54 is determined by generating the difference between each current channel value 40 of the second current data record 54 and the respective allocated prognostic value 80 of the second forecast 78 for forming a difference value. The number of the difference values forms in this context the second deviation 84.

[0060] In a subsequent twelfth operating step 86, a second transmission value 88 which, in consequence, corresponds to the second deviation 84, is generated on the basis of the second deviation 84 by means of spherically logarithmic quantization. The second transmission value 86 is in this context also unidimensional and, for example, essentially the same spherical logarithmic quantization is utilized which is also used for generating the first transmission value 66. The second transmission value 88 is transmitted from the transmitter 18 by the data signals 22 to the receiver 20 of the hearing aid 4 to which the first transmission value 66 has also been transmitted.

[0061] By means of its communication facility 24, a second reconstructed data record 92 is generated in a thirteenth operating step 90. In this context, a second auxiliary data record 94 is generated by the second transmission value 88, a function inverse to the spherically logarithmic quantization being carried out. In consequence, the second auxiliary data record 94, with the exception of any noise which has been introduced due to the quantization, corresponds to the second deviation 84. Furthermore, a second auxiliary forecast 96 is generated in the thirteenth operating step 90 by the first reconstructed data record 74 and by the reconstructed output signal 48 preceding in time and the first reconstructed data record 74, for which purpose a linear prediction is utilized. In this context, the same coefficients are used as for generating the second forecast 78. Due to the essentially equal values used for generating the forecast, the second auxiliary forecast 96, therefore, corresponds essentially to the second forecast 78. For generating the second reconstructed data record 92, the second auxiliary data record 94 is added value by value to the second auxiliary forecast 96. In summary, the second reconstructed data record 92 is generated at the receiver end by the reconstructed output signals 48 preceding in time and the first reconstructed data record 74.

[0062] In a subsequent fourteenth operating step 98, the first reconstructed data record 74 and the second reconstructed data record 92 are combined to form a reconstructed output signal 100 which, in consequence, essentially has the current channel values 40. Any difference exists in this context only due to any quantization effects. The output signal 100 is used as reconstructed output signal 48 preceding in time for repeated execution of the method 26 or at least added to the reconstructed output signal. In a subsequent fifteenth operating step 102, the reconstructed output signal 100 is transformed from the frequency domain into the time domain and, for example, output by the loudspeaker 14.

[0063] Furthermore, a sixteenth operating step 104 is carried out at the transmitter 18 in which, by the first and second transmission values 66, 88 and by utilizing the first and second forecasts 58, 78, a third reconstructed data record 106 is generated. In this context, the ninth operating step 68 and the thirteenth operating step 90 are carried out essentially at the transmitter 18, using the first forecast 58 instead of the first auxiliary forecast 72 and the second forecast 78 instead of the second auxiliary forecast 96. As well, the two reconstructed data records are added in order to form the third reconstructed data record 106. In consequence, the third reconstructed data record 106 corresponds to the output signal 100. In other words, the third reconstructed data record 106 also has some interfering noises due to the quantization used. With a repeated execution of the method 26, the third reconstructed data record 106 is utilized as channel values 44 preceding in time so that both at the transmitter 18 and at the receiver 20, the same input data are in each case used for generating the respective forecasts 58, 72, 78, 96.

[0064] In FIG. 5, a further embodiment of the generation of the first forecast 58 and the generation of the second forecast 78 and, in consequence, also the generation of the two reconstructed data records 74, 92 is shown. In this context, the first current data record 54 only has a single one of the current channel values 44 and, in consequence, the first forecast 58 only contains a single prognostic value 60. By means of the current channel value 40 allocated to this single prognostic value 60, one of the prognostic values 80 of the second forecast 78 is generated and is allocated to the directly adjacent frequency channel 36. The current channel value 40 allocated to this prognostic value 80 is, in turn, utilized in a further operating step for determining a further prognostic value 80 which is allocated to just this value in the directly adjacent frequency channel 36, etc. Alternatively, all prognostic values 80 are generated by the single current channel value 40 of the first current data record 54.

[0065] In FIG. 6, a further embodiment is shown. In this context, the first data record 52 essentially exhibits one fifth of all current channel values 40, these, for example, being allocated to frequency channels 36 which are spaced apart with respect to one another by means of in each case four of the frequency channels 36. To determine the prognostic values 80 of the second forecast 78 and, in consequence, also the second auxiliary forecast 96, these are utilized, the number of prognostic values 80 corresponding to the number of prognostic values 60. Subsequently to this, further prognostic values 80 which are allocated to the directly adjacent frequency band 36 are determined by means of the current channel values 40 allocated to these prognostic values 80 of the second forecast 78. For example, the current channel values 40 are distributed over a number of data records and a number of deviations is determined and a respective transmission value corresponding thereto is transmitted. In other words, the method 26 presented in FIG. 2 is carried out essentially in cascaded manner.

[0066] In summary, due to the use of values already reconstructed or actual values for generating the second forecast 78 and for generating the second auxiliary forecast 96, respectively, any correlation between the frequency channels 36 is taken into consideration so that the second deviation 84 is comparatively small.

[0067] The invention is not restricted to the exemplary embodiments described above. Instead, other variants of the invention can also be derived from said exemplary embodiments by the expert without departing from the subject matter of the invention. In particular, all individual features described in conjunction with the individual exemplary embodiments can also be combined with one another in a different way without departing from the subject matter of the invention.

[0068] The following is a summary list of reference numerals and the corresponding structure used in the above description of the invention: [0069] 2 Hearing device system [0070] 4 Hearing aid [0071] 6 Housing [0072] 8 Microphone [0073] 10 Sound transducer [0074] 12 Signal processing unit [0075] 14 Loudspeaker [0076] 16 Audio signal [0077] 18 Transmitter [0078] 20 Receiver [0079] 22 Data signal [0080] 24 Communication facility [0081] 26 Method [0082] 28 First operating step [0083] 30 Second operating step [0084] 32 Input signal [0085] 34 Time window [0086] 36 Frequency channel [0087] 38 Bandpass filter [0088] 40 Current channel value [0089] 42 Third operating step [0090] 44 Channel value preceding in time [0091] 46 Fourth operating step [0092] 48 Reconstructed output signal preceding in time [0093] 50 Fifth operating step [0094] 52 First current data record [0095] 54 Second current data record [0096] 56 Sixth operating step [0097] 58 First forecast [0098] 60 Prognostic value [0099] 61 Seventh operating step [0100] 62 First deviation [0101] 64 Eighth operating step [0102] 66 First transmission value [0103] 68 Ninth operating step [0104] 70 First auxiliary data record [0105] 72 First auxiliary forecast [0106] 74 First reconstructed data record [0107] 76 Tenth operating step [0108] 78 Second forecast [0109] 80 Prognostic value [0110] 82 Eleventh operating step [0111] 84 Second deviation [0112] 86 Twelfth operating step [0113] 88 Second transmission value [0114] 90 Thirteenth operating step [0115] 92 Second reconstructed data record [0116] 94 Second auxiliary data record [0117] 96 Second auxiliary forecast [0118] 98 Fourteenth operating step [0119] 100 Reconstructed output signal [0120] 102 Fifteenth operating step [0121] 104 Sixteenth operating step [0122] 106 Third reconstructed data record