CN112601155A - Method and system for digital parametric array loudspeaker - Google Patents
Method and system for digital parametric array loudspeaker Download PDFInfo
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- CN112601155A CN112601155A CN202011432180.2A CN202011432180A CN112601155A CN 112601155 A CN112601155 A CN 112601155A CN 202011432180 A CN202011432180 A CN 202011432180A CN 112601155 A CN112601155 A CN 112601155A
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- 238000000034 method Methods 0.000 title claims abstract description 23
- 238000006243 chemical reaction Methods 0.000 claims description 9
- 230000005236 sound signal Effects 0.000 claims description 9
- 238000012545 processing Methods 0.000 claims description 7
- 230000002146 bilateral effect Effects 0.000 claims description 4
- 239000002033 PVDF binder Substances 0.000 claims description 3
- 239000012528 membrane Substances 0.000 claims description 3
- 229920002981 polyvinylidene fluoride Polymers 0.000 claims description 3
- 230000007547 defect Effects 0.000 abstract description 4
- 238000010586 diagram Methods 0.000 description 8
- 238000004088 simulation Methods 0.000 description 5
- 238000012360 testing method Methods 0.000 description 3
- 238000007796 conventional method Methods 0.000 description 2
- 210000005069 ears Anatomy 0.000 description 2
- 230000009022 nonlinear effect Effects 0.000 description 2
- 230000004075 alteration Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
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Classifications
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R1/00—Details of transducers, loudspeakers or microphones
- H04R1/20—Arrangements for obtaining desired frequency or directional characteristics
- H04R1/32—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired directional characteristic only
- H04R1/323—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired directional characteristic only for loudspeakers
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R1/00—Details of transducers, loudspeakers or microphones
- H04R1/20—Arrangements for obtaining desired frequency or directional characteristics
- H04R1/32—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired directional characteristic only
- H04R1/40—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired directional characteristic only by combining a number of identical transducers
- H04R1/403—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired directional characteristic only by combining a number of identical transducers loud-speakers
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R2201/00—Details of transducers, loudspeakers or microphones covered by H04R1/00 but not provided for in any of its subgroups
- H04R2201/40—Details of arrangements for obtaining desired directional characteristic by combining a number of identical transducers covered by H04R1/40 but not provided for in any of its subgroups
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R2430/00—Signal processing covered by H04R, not provided for in its groups
- H04R2430/20—Processing of the output signals of the acoustic transducers of an array for obtaining a desired directivity characteristic
Abstract
The invention relates to a method and a system for a digital parametric array loudspeaker, wherein the method comprises the following steps: the diameter of the transducer is reduced, and the directivity is improved; optimizing the structural layout of the transducer, and matching with a digital driving mode; a multi-channel control transducer; collecting and coding an input analog signal to obtain a digital signal; the digital signal is bilaterally modulated onto a carrier wave to obtain a modulated wave signal; the modulated waves are decoded and sent to a multi-path transducer in a digital form; the method and the system of the digital parametric array loudspeaker effectively improve the directivity of the system by optimizing the size of the ultrasonic transducer, improving the layout of the parametric array loudspeaker and using a digital driving mode, and can achieve the maximum sound pressure difference of 60 degrees inside and outside of 20dB at present, so the method and the system effectively overcome the defects in the prior art and have high industrial utilization value.
Description
Technical Field
The invention relates to the technical field of parametric array loudspeakers, in particular to a method and a system of a digital parametric array loudspeaker.
Background
The parametric array loudspeaker can enable sound to spread like light beams, high-directivity audible sound is generated, different audio information is provided for different users, and personalized sound transmission is achieved. The principle is that when ultrasonic carrier waves propagate in air, due to the nonlinear effect of the ultrasonic waves, difference frequency signals are within the hearing range (20Hz-20kHz) of human ears and are heard by the human ears.
The parametric array loudspeaker utilizes ultrasonic waves to generate audible sound under the action of air self-demodulation, the conventional method is to amplify a power amplifier after analog signal modulation, and the amplified signal is directly sent to transducers connected in parallel. The parametric array loudspeaker is mainly characterized in that the directivity of the ultrasonic wave carrier emitted by the transducer is utilized to obtain the audio signal with strong directivity, and the directivity of the ultrasonic wave beam emitted by the transducer directly determines the directivity of the audio signal. The directivity of the parametric array speaker of the conventional method is not adjustable.
Disclosure of Invention
Aiming at the defects of the prior art, the invention provides the following technical scheme: a method and system for a digital parametric array loudspeaker, the method comprising the steps of: the method comprises the following steps of firstly, reducing the diameter of a transducer and improving the directivity;
step two, optimizing the structural layout of the transducer and matching with a digital driving mode;
step three, controlling the transducer in multiple paths;
acquiring and coding an input analog signal to obtain a digital signal;
step five, the digital signal is bilaterally modulated onto a carrier wave to obtain a modulated wave signal;
and step six, the modulated waves are decoded and sent to a multi-path transducer in a digital form.
Preferably, the system includes an amplifier, a parametric array speaker, an audio input, a processor, a conversion circuit, a memory, and an ultrasonic transducer.
Preferably, the processor comprises a DSP processor, an ARM processor, an FPGA or a single chip microcomputer.
Preferably, the ultrasonic transducer comprises a PZT transducer array and a PVDF membrane transducer.
Preferably, the amplifier is used for amplifying the carrier signal output by the processor to reach the driving voltage of the ultrasonic transmitter.
Preferably, the parametric array speaker is configured to directionally play a processed audio signal, the audio input is configured to collect an input audio, and may collect a digital audio or an analog audio, the processor is configured to load a program and execute a partial bilateral modulation algorithm, the conversion circuit is configured to load 8-bit signals output by the processor into the 8-way ultrasonic ring energy device, and the memory is configured to store the program or store a partial boot code.
Preferably, the memory comprises random access memory, or comprises non-volatile memory.
Preferably, the processor includes a central processing unit, a network processor, a digital signal processor, an application specific integrated circuit, a field programmable gate array or other programmable logic device, discrete gate or transistor logic, discrete hardware components.
Compared with the prior art, the invention has the following beneficial effects: by optimizing the size of the ultrasonic transducer, improving the layout of the parametric array loudspeaker and using a digital driving mode. The directivity of the system is effectively improved, and the maximum sound pressure difference inside and outside 60 degrees can be up to 20dB at present, so that the invention effectively overcomes the defects in the prior art and has high industrial utilization value.
Drawings
FIG. 1 is a schematic diagram of a parametric array loudspeaker of the present invention with improved structure of the transducer of the generating unit;
FIG. 2 is a layout diagram of the ultrasonic transducer according to the present invention and a corresponding digital distribution pattern;
fig. 3 is a directional simulation diagram of a 20 × 13 arrangement;
FIG. 4 is a block diagram of the system of the present invention;
in the figure: 1. an amplifier; 2. a parametric array speaker; 3. audio frequency input; 4. a processor; 5. a conversion circuit; 6. a memory.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Referring to fig. 1-4, a method of digital parametric array speaker, the method comprising the steps of: the method comprises the following steps of firstly, reducing the diameter of a transducer and improving the directivity;
step two, optimizing the structural layout of the transducer and matching with a digital driving mode;
step three, controlling the transducer in multiple paths;
acquiring and coding an input analog signal to obtain a digital signal;
step five, the digital signal is bilaterally modulated onto a carrier wave to obtain a modulated wave signal;
and step six, the modulated waves are decoded and sent to a multi-path transducer in a digital form.
The system comprises an amplifier 1, a parametric array loudspeaker 2, an audio input 3, a processor 4, a conversion circuit 5, a memory 6 and an ultrasonic transducer.
The processor 4 comprises a DSP processor, an ARM processor, an FPGA or a singlechip.
The ultrasonic transducer includes a PZT transducer array and a PVDF membrane transducer.
The amplifier 1 is used for amplifying the carrier signal output by the processor to reach the driving voltage of the ultrasonic transmitter.
The parametric array loudspeaker 2 is used for directionally playing processed audio signals, the audio input 3 is used for collecting input audio and collecting digital audio or analog audio, the processor 4 is used for loading programs and executing a part of bilateral modulation algorithm, the conversion circuit 5 is used for loading 8-bit signals output by the processor into 8-path ultrasonic ring energy devices respectively, and the memory 6 is used for storing programs or storing a part of starting codes.
The memory 6 comprises random access memory, or comprises non-volatile memory.
The processor 4 comprises a central processing unit, a network processor, a digital signal processor, an application specific integrated circuit, a field programmable gate array or other programmable logic device, discrete gate or transistor logic, discrete hardware components.
The parametric array speaker is a technique for modulating an audible sound signal onto an ultrasonic carrier and re-self-demodulating the audible sound signal from a modulated wave by utilizing a nonlinear action of air, and the modulated wave is an ultrasonic wave and has a good directivity, so that the self-demodulated audible sound signal also has a characteristic of directional propagation. However, the conventional simulation method can only achieve a sound pressure difference of 10dB within 60 degrees. Based on the defects of the existing scheme, the scheme provides a method and a system of a digital parametric array loudspeaker.
Fig. 1 is a schematic diagram of a parametric array loudspeaker of the present invention with improved structure of the transducer of the generation unit.
In the above formula, k is the wave number,
f is the ultrasonic carrier frequency, c is the sound velocity in the air; m and N correspond to the number of transducers in the X and Y axes, respectively, and d is the distance between the centers of adjacent ring transducers. Alpha is the included angle between the X axis and the X axis of the test point in the XY plane, and theta is the included angle between the Z axis and the test point in the Z axis. Wherein M is 20, and N is 13.
Through simulation and actual tests, the smaller the distance d is, the better the directivity of the parametric array loudspeaker is. The structure of the ultrasonic transducer is optimized, and fig. 1 is a schematic diagram of the optimized transducer. The diameter of the current transducer is 7.4mm, and the center distance of the adjacent ultrasonic transducers behind the actual plate distribution is 7.5 mm.
Fig. 2 is a layout diagram of the ultrasonic transducers and the corresponding digital distribution mode.
The digital expression is 8-bit deep, so the number of sensors is 20, 21, 22, 23, 24, 25, 26, 27, and the total number is 255 ultrasonic ring energy devices. The layout modes such as 8 × 32, 16 × 16 and 20 × 13 are adopted for analysis in sequence, and finally the best directional effect is achieved according to the layout mode of 20 × 13 in simulation and actual measurement. Fig. 3 is a directional simulation diagram of a 20 × 13 arrangement.
The digital parametric array loudspeaker is different from the analog parametric array in the following maximum differences: all the ultrasonic transducers of the analog parametric array are connected in parallel. And the transducer of the digital parametric speaker is in an 8-way parallel connection mode. That is, the ultrasonic ring transducers with the same serial number in fig. 2 are connected in parallel, and 8 channels in total correspond to the bit depth of 8 bits.
Those skilled in the art should understand that the division of the modules in the embodiment of fig. 4 is only a logical division, and the actual implementation can be fully or partially integrated into one or more physical entities. And the modules can be realized in a form that all software is called by the processing element, or in a form that all the modules are realized in a form that all the modules are called by the processing element, or in a form that part of the modules are called by the hardware. For example, the 1 amplifier module may be a single component or may be implemented by a chip. Other modules are implemented similarly. The processor described herein may be an integrated circuit having signal processing capabilities. In the implementation process, each step of the above method or each module above may be implemented by an integrated logic circuit of hardware in a processor or an instruction in the form of software.
Referring to fig. 4, the present embodiment provides a hardware platform, which includes an amplifier 1, a parametric array speaker 2, an audio input 3, a processor 4, a conversion circuit 5, and a memory 6.
The amplifier 1 is used for amplifying the carrier signal output by the processor so as to reach the driving voltage of the ultrasonic transmitter;
the parametric array loudspeaker 2 is used for directionally playing the processed audio signals;
the audio input 3 is used for collecting input audio, and can collect digital audio or analog audio;
the processor 4 is used for loading a program and executing a part of bilateral modulation algorithm;
the conversion circuit 5 is used for loading 8-bit signals output by the processor into the 8-path ultrasonic ring energy devices respectively;
the memory 6 is used for storing programs or storing part of the starting codes;
the Memory 6 may include a Random Access Memory (RAM), and may further include a non-volatile Memory (non-volatile Memory), such as at least one disk Memory.
The Processor 4 may be a general-purpose Processor, and includes a Central Processing Unit (CPU), a Network Processor (NP), and the like; the Integrated Circuit may also be a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other programmable logic device, discrete gate or transistor logic device, discrete hardware component.
In summary, the present invention provides a method and system for a digital parametric array speaker by optimizing the size of the ultrasonic transducer, improving the layout of the parametric array speaker and using a digital driving method. Effectively improves the directivity of the system, and can reach the maximum sound pressure difference of 20dB inside and outside 60 degrees at present. Therefore, the present invention effectively overcomes the disadvantages of the prior art and has a high industrial utility value.
Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.
Claims (8)
1. A method of digital parametric array loudspeakers, the method comprising the steps of:
the method comprises the following steps of firstly, reducing the diameter of a transducer and improving the directivity;
step two, optimizing the structural layout of the transducer and matching with a digital driving mode;
step three, controlling the transducer in multiple paths;
acquiring and coding an input analog signal to obtain a digital signal;
step five, the digital signal is bilaterally modulated onto a carrier wave to obtain a modulated wave signal;
and step six, the modulated waves are decoded and sent to a multi-path transducer in a digital form.
2. A system of digital parametric array loudspeakers in accordance with claim 1, wherein: the system comprises an amplifier (1), a parametric array loudspeaker (2), an audio input (3), a processor (4), a conversion circuit (5), a memory (6) and an ultrasonic transducer.
3. A system of digital parametric array loudspeakers in accordance with claim 2, wherein: the processor (4) comprises a DSP processor, an ARM processor, an FPGA or a singlechip.
4. A system of digital parametric array loudspeakers in accordance with claim 2, wherein: the ultrasonic transducer comprises a PZT transducer array and a PVDF membrane transducer.
5. A system of digital parametric array loudspeakers in accordance with claim 2, wherein: the amplifier (1) is used for amplifying the carrier signal output by the processor so as to reach the driving voltage of the ultrasonic transmitter.
6. A system of digital parametric array loudspeakers in accordance with claim 2, wherein: the parametric array loudspeaker (2) is used for directionally playing processed audio signals, the audio input (3) is used for collecting input audio and collecting digital audio or analog audio, the processor (4) is used for loading programs and executing a part of bilateral modulation algorithm, the conversion circuit (5) is used for loading 8-bit signals output by the processor into 8 paths of ultrasonic ring energy devices respectively, and the memory (6) is used for storing the programs or storing a part of start codes.
7. A system of digital parametric array loudspeakers in accordance with claim 2, wherein: the memory (6) comprises random access memory, or comprises non-volatile memory.
8. A system of digital parametric array loudspeakers in accordance with claim 2, wherein: the processor (4) comprises a central processing unit, a network processor, a digital signal processor, an application specific integrated circuit, a field programmable gate array or other programmable logic device, discrete gate or transistor logic, discrete hardware components.
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| CN202011432180.2A CN112601155A (en) | 2020-12-10 | 2020-12-10 | Method and system for digital parametric array loudspeaker |
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| CN202011432180.2A CN112601155A (en) | 2020-12-10 | 2020-12-10 | Method and system for digital parametric array loudspeaker |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115499738A (en) * | 2022-09-21 | 2022-12-20 | 电子科技大学 | Programmable parametric array speaker with safety device |
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