Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04S—STEREOPHONIC SYSTEMS 
  • H04S7/00—Indicating arrangements; Control arrangements, e.g. balance control
  • H04S7/30—Control circuits for electronic adaptation of the sound field
  • H04S7/301—Automatic calibration of stereophonic sound system, e.g. with test microphone
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
  • H04R2499/00—Aspects covered by H04R or H04S not otherwise provided for in their subgroups
  • H04R2499/10—General applications
  • H04R2499/13—Acoustic transducers and sound field adaptation in vehicles

Definitions

• the invention relates to a method for operating a motor vehicle audio output device which is set up for outputting audio signals into a passenger compartment of a motor vehicle, the output of audio signals being carried out on the basis of a transfer function having an amplitude and a phase component.
• Corresponding methods for operating motor vehicle-side audio output devices which are set up for outputting audio signals into a passenger compartment of a motor vehicle, are basically known from the prior art in a large number of different embodiments.
• the output of audio signals as part of the implementation of corresponding methods is typically based on a motor vehicle-specific transfer function.
• the audio tuning is typically carried out. This is a measure to be carried out by a tuner, in particular manually, in which a corresponding audio output device or its operation is set to the specific acoustic properties of a passenger compartment of a specific motor vehicle.
• Audio tuning is a very complex and complex measure which requires specially trained or trained tuning personnel. Audio tunings therefore regularly end up with a compromise between the effort involved in audio tuning and the quality of the tuning result.
• the invention is based on the object of specifying an improved method for operating a motor vehicle-side audio output device, in particular with regard to a simpler possibility of corresponding audio tuning.
• the object is achieved by a method for operating a motor vehicle-side audio output device, which is set up to output audio signals into a passenger compartment of a motor vehicle, the output of audio signals being carried out on the basis of a transmission function having an amplitude and a phase component.
• the dependent claims relate to possible or expedient embodiments of the method.
• the method described here is used to operate a motor vehicle, ie. H. Audio output device to be installed or installed in a motor vehicle, which is set up for outputting audio signals into a passenger compartment of a motor vehicle.
• the method thus also serves to output audio signals in a passenger compartment of a motor vehicle.
• the operable or operated audio output device can, for. B. as a motor vehicle-side entertainment device and / or a motor vehicle-side multimedia device, which is set up to output entertainment content and / or multimedia content to at least one vehicle occupant located within the passenger compartment, be formed or form part of such a vehicle.
• An audio output device that can be operated or operated in accordance with the method comprises, in addition to a control device that controls its operation and is implemented in hardware and / or software, typically one or more audio output units, ie. H. typically loudspeaker units, in short loudspeakers, via which the actual output of audio signals into the passenger compartment of the motor vehicle equipped with the audio output device takes place.
• a control device that controls its operation and is implemented in hardware and / or software
• typically one or more audio output units ie. H. typically loudspeaker units, in short loudspeakers, via which the actual output of audio signals into the passenger compartment of the motor vehicle equipped with the audio output device takes place.
• An audio signal which can be output or output by means of the audio output device in a passenger compartment is typically a music signal and / or a voice signal.
• a corresponding music or speech signal can in principle be via any physical and / or non-physical signal source, ie for example via a sound carrier such as. B. a CD, a memory card, etc., an external terminal such. B. a cell phone, a smartphone, a tablet, a notebook, etc., or a local or global network, ie B. a radio wave network, the Internet, etc., are provided and the audio output device can be signaled.
• the term “audio signal” can also include a large number of acoustically identical or different audio signals.
• the output of audio signals which can be carried out or carried out by means of the audio output device takes place on the basis of a transfer function which has an amplitude and a phase component.
• the transfer function is defined in particular by the acoustic properties of the passenger compartment of the motor vehicle equipped with the audio output device.
• a transfer function is provided.
• the transfer function which generally describes the relationship between the input and output signal of a linear dynamic system in the frequency domain, is typically determined by the acoustic properties of the passenger compartment, i. H.
• the acoustic properties of the passenger cell not occupied by vehicle occupants, of the motor vehicle equipped with the audio output device operable or operated according to the method are defined or predefined.
• the first step of the method can therefore also be referred to or considered as specifying a transfer function.
• the transfer function has an amplitude and a phase component, in short an amplitude and a phase.
• the transfer function is therefore typically defined by an amplitude and a phase component, in short an amplitude and a phase.
• the amplitude and the phase component of the transfer function are typically determined by the acoustic properties of the passenger cell, that is to say in particular the acoustic properties of the passenger cell that is not occupied by vehicle occupants, and the one that can be operated by the method or operated audio output device equipped motor vehicle defined or specified.
• the amplitude component of the transfer function is essentially determined by the acoustic properties of the passenger compartment of the vehicle that can be operated or operated audio output device equipped motor vehicle defined or specified.
• a frequency-dependent group delay function of the phase component of the transfer function is determined. Extracting the phase component of the transfer function can precede the determination of the frequency-dependent group delay function of the phase component.
• the frequency-dependent group delay function of the phase component can in particular be determined by calculation.
• the determination of the frequency-dependent group delay function of the phase portion of the transfer function can specifically z. B. done by applying a first determination function or regulation to the transfer function.
• a first determination function or rule can then be applied to the transfer function, via which the phase portion of the transfer function can be determined.
• the application of the first determination function or regulation which can also be referred to or regarded as the first determination algorithm, can be carried out by a first determination device implemented in terms of hardware and / or software.
• a corresponding first determination device can form a functional component of a functionally higher-level control device of the audio output device.
• a target group delay function in particular frequency-independent
• the target group runtime function can e.g. B. user side, d. H. in particular by a tuner.
• the predefined target group delay function is, as indicated, in particular independent of frequency.
• the predetermined target group delay function differs from the previously determined frequency-dependent group delay function in at least one property; Since the specified target group delay function, as mentioned, is in particular frequency-independent, the specified target group delay function differs from the previously determined frequency-dependent group delay function in particular by its frequency independence.
• a partial difference function is determined, which is a difference between the group runtime function and the target group runtime function in a specific frequency interval, ie, for example, in one Frequency interval between 150 Hz and 1500 Hz, describes or represents a frequency band.
• the partial difference function can in particular be calculated by calculating a difference between the group runtime function and the target group runtime function.
• the partial difference function can be determined by applying a second determination function or rule to the group runtime function or the target group runtime function.
• a second determination function or rule can then be applied to the group runtime function or the target group runtime function, via which the difference between the group runtime function and the target group runtime function can be determined.
• the application of the second determination function or regulation which, analogously to the first determination function or regulation, can also be referred to or regarded as the second determination algorithm, can be carried out by a second determination device implemented in hardware and / or software.
• a corresponding second determination device can also form a functional component of the or a functionally higher-level control device of the audio output device.
• the partial difference function is modified by at least one modification measure while maintaining a modified partial difference function for the or in the specific frequency interval of the frequency band.
• the modification of the partial difference function for or in the specific frequency interval of the frequency band can be carried out by applying a modification measure.
• the modification measure can include at least one modification function or regulation.
• a modification function or regulation can then be used, by means of which the partial difference function can be modified for or in the specific frequency interval of the frequency band.
• the modification function or regulation which can also be referred to or viewed as a modification algorithm, can be applied by a modification device implemented in hardware and / or software.
• a corresponding modification device can also form a functional component of the or a functionally higher-level control device of the audio output device.
• the phase component of the is determined modified partial difference function, in particular by converting the modified partial difference function.
• the phase component of the modified partial difference function can be determined in particular by converting the modified partial difference function.
• the phase component of the modified partial difference function can in particular be calculated by calculating the phase component of the modified partial differential function from the modified partial differential function.
• the phase component of the modified partial difference function can be determined by applying a third determination function or rule to the modified partial difference function.
• the third determination function or regulation can be a conversion function or regulation for converting the modified partial difference function.
• a third determination function or rule can then be applied to the modified partial difference function, via which the phase component of the modified partial difference function can be determined.
• the application of the third determination function or regulation which, analogously to the first or second determination function or regulation, can also be referred to or regarded as the third determination algorithm, can be implemented by a third hardware and / or software-implemented determination device, which, for. B. designed as a conversion device or can include such.
• a corresponding third determination device can also form a functional component of the or a functionally higher-level control device of the audio output device.
• a correction function is generated for correcting the transfer function provided in the first step on the basis of the determined phase component of the modified partial difference function.
• the phase component of the modified partial difference function determined in the sixth step is then used to correct the transfer function provided.
• the correction function can be a correction function or regulation, which can also be referred to or viewed as a correction algorithm. As follows, the correction function serves in particular to obtain a group delay function approximated to the target group delay function.
• the correction function generated in the seventh step is applied to the one provided in the first step Transfer function while receiving a group runtime function approximated to the target group runtime function.
• the correction function can be applied to the transfer function in particular by calculation.
• the group delay function approximated to the target group delay function can then be obtained by applying a correction function or regulation to the transfer function.
• a third correction function or rule can be applied to the transfer function, via which a group delay function approximated to the target group delay function can be obtained.
• the correction function or regulation which can also be referred to or viewed as a correction algorithm, can be applied by a correction device implemented in hardware and / or software.
• a corresponding correction device can of course also form a functional component of the or a functionally higher-level control device of the audio output device.
• audio signals are output on the basis of the group delay function approximated to the target group delay function. Audio signals are therefore output on the basis of the group delay function approximated to the target group delay function. The audio signals are then output taking into account the group delay function approximated to the target group delay function.
• the group delay function approximated to the target group delay function used in the ninth step of the method differs from the transfer function provided in the first step of the method at least by the phase component.
• the principle according to the method provides an improved method for operating a motor vehicle-side audio output device, in particular with regard to a simpler possibility of corresponding audio tuning.
• the method described here can also be used as a method for tuning a motor vehicle-side audio output device which is set up for outputting audio signals into a passenger compartment of a motor vehicle, the output of audio signals based on a transmission function having an amplitude and a phase component, or according to the method on the basis of a to a target group runtime function approximated, in particular on the tuner side, predetermined group runtime function done, designated or considered.
• a partial difference function can be determined, which describes a difference between the group delay function and the target group delay function in a frequency interval from the or a frequency band determined by a lower and an upper limit frequency.
• the difference between the group delay function and the target group delay function can occur in a frequency interval between 150 Hz and 1500 Hz.
• a lower cut-off frequency can therefore, for. B. at 150 Hz, an upper limit frequency can z. B. are at 1500 Hz.
• an at least section-wise, possibly complete, smoothing can be carried out by applying at least one smoothing function or regulation.
• the smoothing function is applied to the partial difference function, whereby the modified partial difference function is obtained.
• the smoothing can be carried out in particular with regard to the method used to carry out the method, i. H.
• the computational effort required to generate the group delay function approximated to the target group delay function may be expedient.
• the smoothing function or regulation can be applied by a smoothing device implemented in hardware and / or software.
• a corresponding smoothing device can form a functional component of the audio output device or a functionally higher-level control device of the audio output device.
• a smoothing function or regulation generated on the basis of a psychoacoustic scale can expediently be used as the smoothing function or regulation.
• a smoothing function or regulation generated on the basis of a psychoacoustic scale namely a Bark scale
• the smoothing function or regulation produced delivers very good results with regard to the acoustic properties of the audio signal to be output according to the method.
• At least one modification measure can be used Sectional, possibly complete, compression of the partial difference function is carried out by applying at least one compression function or rule.
• the compression function or regulation can therefore be applied in particular to the partial difference function, which may be smoothed. Compression can also be expedient, in particular with regard to the computational outlay required to carry out the method, ie in particular the group runtime function approximated to generate the target group runtime function.
• the compression function or regulation can be applied by a compression device implemented in hardware and / or software.
• a corresponding compression device can form a functional component of the audio output device or a functionally higher-level control device of the audio output device.
• a compression function or regulation comprising an upper and a lower compression limit value can be used as the compression function or regulation.
• the compression can take place in clearly delimited or delimited areas, which typically leads to an improved compression result.
• an at least partial, possibly complete, saturation can take place by applying at least one saturation function or regulation.
• the partial difference function can be saturated.
• the saturation function or regulation is applied to the partial difference function, optionally smoothed and / or compressed. Saturation can be expedient in particular with regard to the acoustic properties of the audio signal that can be output or output according to the method.
• the saturation function or regulation can be applied by a saturation device implemented in hardware and / or software. A corresponding saturation device can form a functional component of the audio output device or a functionally higher-level control device of the audio output device.
• a saturation function or regulation comprising an upper and a lower saturation limit value can be used as the saturation function or regulation.
• the saturation can take place in clearly delimited or delimited areas, which typically leads to an improved saturation result.
• the correction function applied according to the method can be in a filter device, i. H. in particular in a FIR filter device, the audio output device.
• the correction function can be used as a basis for the operation of a corresponding filter device.
• the correction of the transfer function provided can then include filtering the transfer function provided.
• the invention also relates to an audio output device for a motor vehicle.
• the audio output device is set up for outputting audio signals into a passenger compartment of a motor vehicle equipped therewith, the output of audio signals basically on the basis of a transfer function having an amplitude and a phase component, or by means of the audio output device on the basis of a predetermined target, in particular on the tuner side -Group runtime function approximated group runtime function.
• the audio output device is in particular set up to carry out the method described herein.
• the audio output device is therefore in particular for determining a frequency-dependent group delay function of the phase component of a transfer function provided with the audio output device and having an amplitude and a phase component; Specifying a target group delay function, in particular frequency-independent; Determining a partial difference function, which describes a difference between the group delay function and the target group delay function in a specific frequency interval of a frequency band; Modifying the partial difference function by means of at least one modification measure while obtaining a modified partial difference function for the specific frequency interval of the frequency band - determining the phase component of the modified partial difference function, in particular by converting the modified partial difference function; Create one Correction function for correcting the transfer function provided on the basis of the determined phase component of the modified partial difference function; Applying the correction function to the provided transfer function while obtaining a group delay function approximated to the target group delay function; and - outputting audio signals on the basis of the group delay function approximated to the target group delay function.
• the invention relates to a motor vehicle which comprises at least one corresponding audio output device.
• the audio output device is set up for outputting audio signals into the passenger compartment of the motor vehicle.
• the motor vehicle is in particular a passenger car.
• FIG. 3 shows a basic illustration of a motor vehicle-side audio output device according to an exemplary embodiment.
• FIG. 1 shows a basic illustration of a flowchart to illustrate a method according to a first exemplary embodiment. The method is used in particular for the operation of a motor vehicle, ie. H. Audio output device 1 (cf. FIG. 3) to be installed or installed in a motor vehicle 2, which is set up for outputting audio signals 3 into a passenger compartment 4 of a motor vehicle 2.
• a motor vehicle ie. H. Audio output device 1 (cf. FIG. 3)
• a motor vehicle 2 ie. H. Audio output device 1 (cf. FIG. 3) to be installed or installed in a motor vehicle 2, which is set up for outputting audio signals 3 into a passenger compartment 4 of a motor vehicle 2.
• the audio output device 1 can be a motor vehicle-side entertainment device and / or a motor vehicle-side multimedia device which is used to output entertainment content and / or multimedia content to at least one inside the passenger compartment 4 of the motor vehicle 2 equipped with the audio output device 1 vehicle occupants is set up, be trained or form part of such.
• the audio output device 1 comprises one or more audio output unit (s) 5, ie. H. typically loudspeaker unit (s), briefly loudspeaker, via which the actual output of audio signals into the passenger compartment 4 of the motor vehicle 2 equipped with the audio output device 1 takes place.
• audio output unit (s) 5 ie. H. typically loudspeaker unit (s), briefly loudspeaker, via which the actual output of audio signals into the passenger compartment 4 of the motor vehicle 2 equipped with the audio output device 1 takes place.
• An audio signal 3 that can be output or output by means of the audio output device 1 into the passenger compartment 4 is typically a music signal and / or a voice signal.
• the method comprises the steps described in more detail below:
• a transfer function is provided in a first step S1 of the method.
• the transmission function is defined or predefined by the acoustic properties of the passenger cell 4 of the motor vehicle 2 equipped with the audio output device 1 and not occupied by vehicle occupants.
• the first step S1 of the method can therefore also be referred to or considered as specifying a transfer function.
• the transfer function has an amplitude and a phase component, in short an amplitude and a phase.
• the transfer function is thus defined by an amplitude and a phase component, in short an amplitude and a phase.
• the amplitude and phase component of the transmission function are also defined or predefined by the acoustic properties of the passenger cell 4 of the motor vehicle 2 equipped with the audio output device 1 and not occupied by vehicle occupants.
• the amplitude component of the transfer function is defined or predetermined by the acoustic properties of the passenger compartment of the motor vehicle equipped with an audio output device that can be operated or operated according to the method.
• a frequency-dependent group delay function of the phase component of the transfer function is determined. Extracting the phase component of the transfer function can precede the determination of the frequency-dependent group delay function of the phase component.
• the frequency-dependent group delay function of the phase component of the transfer function is determined by applying a first determination function or rule to the transfer function.
• a first determination function or regulation is then applied to the transfer function, via which the phase portion of the transfer function can be determined.
• the application of the first determination function or regulation which can also be referred to or viewed as the first determination algorithm, is carried out by a first determination device 7 implemented in terms of hardware and / or software.
• the first determination device 7 forms a functional component of the functionally higher-level control device 6 of the Audio output device 1 (see FIG. 3).
• a target group runtime function is specified.
• the target group runtime function can e.g. B. user side, d. H. in particular by a tuner.
• the specified target group delay function is typically frequency-independent.
• the predetermined target group delay function differs from the previously determined frequency-dependent group delay function in at least one property; since the specified target group delay function is, as mentioned, typically frequency-independent, the specified target group delay function differs from the previously determined frequency-dependent group delay function in particular by its frequency independence.
• a partial difference function is determined, which describes or describes a difference between the group delay function and the target group delay function in a specific frequency interval, ie, in a frequency interval between 150 Hz and 1500 Hz, of a frequency band. represents.
• the partial difference function can be determined by arithmetically forming a difference between the group runtime function and the target group runtime function.
• the partial difference function is determined by applying a second determination function or rule to the group runtime function or the target
• the application of the second determination function or regulation which can be referred to or regarded as the second determination algorithm analogously to the first determination function or regulation, is carried out by a second determination device 8 implemented in hardware and / or software.
• the second determination device 8 also forms a functional component of the functionally higher-level control device 6 of the audio output device 1 (cf. FIG. 3).
• the partial difference function is modified by at least one modification measure while maintaining a modified partial difference function for the or in the determined frequency interval of the frequency band.
• the modification of the partial difference function for or in the determined frequency interval of the frequency band can be carried out by using at least one
• the modification measure can include at least one modification function or regulation.
• a modification function or regulation can then be used, via which the partial difference function for the or in the specific frequency interval of the frequency band can be modified.
• the application of the modification function or regulation which can also be referred to or viewed as a modification algorithm, is carried out by a hardware and / or software implemented
• Modification device 9 also forms a functional component of the functionally higher-level control device 6 of the audio output device 1 (cf. FIG. 3).
• the phase component of the modified partial difference function is determined in a sixth step S6 of the method.
• the phase component of the modified partial difference function can be determined by converting the modified partial difference function.
• the phase component of the modified partial difference function is determined by applying a third determination function or rule to the target group delay function.
• the third determination function or regulation can be a conversion function for converting the modified partial difference function or regulation.
• a third determination function or rule is then applied to the target group runtime function, via which the phase component of the modified partial difference function can be determined.
• the application of the third determination function or regulation which, analogously to the first or second determination function or regulation, can also be referred to or regarded as the third determination algorithm, is carried out by a third hardware and / or software-implemented determination device 10, which, for. B. formed as a conversion device or may include such.
• the third determination device 10 also forms a functional component of the functionally superordinate control device 6 of the audio output device 1 (cf. FIG. 3).
• a correction function is generated for correcting the transfer function provided in the first step S1 on the basis of the determined phase component of the modified partial difference function.
• the phase component of the modified partial difference function determined in the sixth step S6 is then used to correct the transfer function provided.
• the correction function can be a correction function or regulation, which can also be referred to or viewed as a correction algorithm.
• the correction function is used in particular to obtain a group delay function approximated to the target group delay function.
• step S8 of the method the correction function generated in the seventh step S7 is applied to the one provided in the first step S1
• the correction function can be applied to the transfer function in particular by calculation.
• the group delay function approximated to the target group delay function can then be obtained by applying a correction function or regulation to the transfer function.
• a third correction function or rule is then applied to the transfer function, via which a Group runtime function maintains approximate group runtime function.
• the correction function or regulation which can also be referred to or viewed as a correction algorithm, is applied by a correction device 15 implemented in hardware and / or software.
• the correction device 15 can also form a functional component of the control device 6 of the audio output device 1.
• a ninth step S9 of the method audio signals 3 are output on the basis of the group delay function approximated to the target group delay function. Audio signals are therefore output on the basis of the group delay function approximated to the target group delay function. The audio signals are then output taking into account the group delay function approximated to the target group delay function.
• the group delay function approximated to the target group delay function in the ninth step S9 of the method differs from the transfer function provided in the first step S1 of the method at least by the phase component.
• a partial difference function can be determined, which describes a difference between the group delay function and the target group delay function in a frequency interval from the or a frequency band determined by a lower and an upper limit frequency.
• a lower cut-off frequency can e.g. B. at 150 Hz, an upper limit frequency z. B. are at 1500 Hz.
• the correction function can in a filter device 14, i. H. in particular in a FIR filter device, the audio output device 1 are stored. The correction function can then be used as the basis for the operation of a corresponding filter device 14.
• FIGS. 1 and 2 shows a basic illustration of a flowchart to illustrate a method according to a second exemplary embodiment.
• the exemplary embodiments shown in FIGS. 1 and 2 can be combined with one another as desired.
• the exemplary embodiment shown in FIG. 2 differs from the exemplary embodiment shown in FIG. 1 by the optional additional steps explained below:
• smoothing is carried out by applying at least one smoothing function or regulation, cf. Step S4 '.
• the smoothing function or regulation is applied to the partial difference function, whereby the modified partial difference function is obtained.
• the smoothing can be done by a hardware and / or software implemented smoothing device 11 (optional).
• the smoothing device 11 can form a functional component of the functionally higher-level control device 6 of the audio output device 1 (cf. FIG. 3).
• a smoothing function or regulation generated on the basis of a psychoacoustic scale can be used as the smoothing function or regulation.
• a smoothing function or regulation generated on the basis of a psychoacoustic scale, namely a Bark scale, can be used particularly expediently, the smoothing taking place in particular within a bandwidth of one Bark.
• the partial differential function can be compressed by applying at least one compression function or regulation, cf. Step S4 ".
• the compression function or regulation can in particular be applied to the partial difference function, which may be smoothed.
• the compression function or regulation is applied by a compression device 12 implemented as hardware and / or software (optional).
• the compression device 12 can form a functional component of the functionally higher-level control device 6 of the audio output device 1.
• a compression function or regulation comprising an upper and a lower compression limit value can be used as the compression function or regulation.
• saturation can take place by applying at least one saturation function or regulation to the partial difference function , see. step S4 '".
• the saturation function or regulation is applied in particular to the partial difference function, which may be smoothed and / or compressed.
• the saturation function or regulation is implemented by a saturation device 13 implemented in hardware and / or software.
• the saturation device 13 (optional ) can form a functional component of the functionally higher-level control device 6 of the audio output device 1.
• a saturation function or regulation comprising an upper and a lower saturation limit value can be used as the saturation function or regulation.
• the audio output device 1 for determining a frequency-dependent group delay function of the phase component of a transfer function provided to the audio output device and having an amplitude and a phase component; Specifying a target group delay function, in particular frequency-independent; Determining a partial difference function, which describes a difference between the group delay function and the target group delay function in a specific frequency interval of a frequency band; Modifying the partial difference function by means of at least one modification measure while obtaining a modified partial difference function for the specific frequency interval of the frequency band - determining the phase component of the modified partial difference function, in particular by converting the modified partial difference function; Generating a correction function for correcting the transfer function provided on the basis of the determined phase component of the modified partial difference function; Applying the correction function to the provided transfer function while obtaining a group delay function approximated to the target group delay function; and - outputting audio signals on the basis of the group delay function approximated to the target group delay function

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• Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• Acoustics & Sound (AREA)
• Signal Processing (AREA)
• Fittings On The Vehicle Exterior For Carrying Loads, And Devices For Holding Or Mounting Articles (AREA)
• Circuit For Audible Band Transducer (AREA)
• Stereophonic System (AREA)

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• 2018
  • 2018-09-12 WO PCT/EP2018/074672 patent/WO2020052756A1/de unknown
  • 2018-09-12 EP EP18769355.1A patent/EP3850870A1/de active Pending
  • 2018-09-12 CN CN201880097491.2A patent/CN112703749B/zh active Active

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