WO2019225773A1 - Improved ultrasound super-directional speaker system and frequency modulation processing method therefor - Google Patents

Abstract

The present invention relates to an improved ultrasound super-directional speaker system and a frequency modulation processing method therefor. Disclosed are an improved ultrasound super-directional speaker system and a frequency modulation processing method therefor, the improved ultrasound super-directional speaker system comprising: a processor including a general speaker function and software for performing ultrasound signal modulation generation; and an amplifier including a middle device, which receives a signal modulated by the processor so as to be capable of recreating the received signal in real time. According to the present invention, provided are: an improved ultrasound super-directional speaker system, which is less expensive and smaller than a conventional amplifier so as to have lower production costs and provide a variety of applications, is configured and processed in a frequency band that is more intuitive and facilitates access, and can implement an algorithm for improving processing speed through gain unification; and a frequency modulation processing method therefor.

Description

Improved Ultrasonic Superdirectional Speaker System and Frequency Modulation Processing Method Therefor

The present invention relates to an improved ultrasonic super-directional speaker system and a frequency modulation processing method therefor, and more particularly, to an improved ultrasonic super-directional speaker system for improving the compactness, low power, and user convenience. It is about a method.

The contents described in this section merely provide background information on the present embodiment and do not constitute a prior art.

The super directional speaker is a speaker that can be heard only in a specific area by aiming the sound like a light, and there is a wide range of applications such as an exhibition system, a bus station, and a guide system for the visually impaired. Super-directional speaker is a special speaker that modulates a sound signal and delivers it on an ultrasonic signal. The sound transmission distance is up to 300m, far more than the normal speaker.

Ultrasound is a type of acoustic vibration that refers to sound waves beyond the range a human can hear. Audible range varies from person to person, but the average human can hear from 20Hz to 20,000Hz. Thus, in ultrasonic technology, sound waves with frequencies above 20,000 Hz are called ultrasonic waves.

Ultrasound is not audible at all because it is a frequency region outside of the audible range a human can hear. However, when the ultrasonic beam passes through the space, the ultrasonic wave is distorted in a predictable direction due to the intrinsic property of the space (nonlinearity). This distortion can be transformed into audible frequency components, which can be used as super-directional speakers when accurately predicted and precisely adjusted.

An ultrasonic speaker is a device for reproducing an audio signal of an audio band from an ultrasonic wave above the audible band, and is an advanced acoustic device by combining ultrasonic waves and sound waves.

The linearity of ultrasonic waves and the flat frequency band characteristics of ultrasonic transducers and the conversion of acoustic energy are high efficiency, and there is no sound quality degradation due to harmonics. In addition, since there is no limitation of a low pass band due to mechanical resonance like a conventional speaker, and an enclosure is not necessary as a speaker system, it is possible to improve sound quality, improve band characteristics, and improve efficiency compared to a conventional speaker system. In addition, the advantages of easily generating the entire audible sound range and directing in a specific direction are very large, so it can be applied to various IT fields.

Ultrasonic superdirectional speakers according to the prior art, which combines these advantages, need to be equipped with an amplifier in addition to the functions of a general speaker as well as additional functions for digital modulation and amplification into the ultrasonic region. With the development of device technology and digital technology, low power driving and miniaturization of speakers and amplifiers are required. Speakers (elements) are capable of low-power operation and miniaturization due to advances in device technology, but a new hardware (H / W) architecture is required for amplifiers according to the prior art, and for this purpose, functions of existing amplifiers on hardware (H / W), digital modulation And reduction of amplification function is required.

On the other hand, the ultrasonic super-directional speaker must transmit a 48 kHz sound source modulated signal of the ultrasonic region (40 kHz carrier). For this, over 480kHz (48kHz x 10x, 40kHz x 8x) modulated signal should be sent out, so oversampling and modulation operation of sound source are needed, and operation in time domain for oversampling and modulation (Hilbert Transform) respectively. In addition to Convolution, the existing Recursive Digital Filter for Equalizer is intertwined.

However, in the time domain setting method according to the prior art, the characteristics of the sound quality may vary according to the settings of the Recursive Digital Filter parameter, the dynamic range control (DRC) gain factor, the number of convolution parameters, and the like. It is more difficult for the non-expert public to predict the impact, making tuning of the sound source quite difficult.

Accordingly, the present invention is to propose an improved ultrasonic super-directional speaker system and a frequency modulation processing method therefor that can solve the above technical limitations.

The present invention has been proposed to solve the above-mentioned problems of the prior art, and is an improved ultrasonic super-directional speaker system and frequency for the same, which can provide cost reduction and diversification (flexibility) due to being cheaper and smaller in size than existing amps. The main purpose is to provide a modulation processing method.

In addition, another object of the present invention is to improve the ultrasonic super-directional speaker system to implement an algorithm that improves the processing speed through the gain matrix unification, as well as setting and processing in a more intuitive and accessible frequency band And to provide a frequency modulation processing method for this.

The problem to be solved of the present invention is not limited to those mentioned above, and another problem to be solved which is not mentioned will be clearly understood by those skilled in the art from the following description.

One aspect of the present invention for achieving the above object is a processor including a function of the general speaker and the software for generating the ultrasonic signal modulation; And an amplifier comprising an intermediate apparatus capable of receiving a modulated signal and reproducing in real time in the processor.

Another aspect of the present invention, the step of representing the source signal in a diagonal matrix for adjusting the gain of a specific frequency by frequency analysis through a Discrete Fourier Transform (DFT) or Fast Fourier Transform (FFT) matrix; Representing the source signal in a Hilbert Fourier Transform (HFT) constant matrix according to components of a DFT constant matrix; Representing the equalizer and the filter in a diagonal matrix according to the frequency characteristic setting; And expressing the sum / difference / difference of the diagonal constant matrix for sine carrier and the diagonal constant matrix for cosine carrier for modulating the signal passed through the equalizer and the filter. A modulation processing method is provided.

Another aspect of the invention, the processor comprising a function of the general speaker and the software for generating the ultrasonic signal modulation; And an amplifier including an intermediate apparatus capable of receiving a modulated signal from the processor and reproducing the signal in real time, and calculating the modulated signal as one unified gain matrix through frequency analysis through a DFT and an IDFT. An improved ultrasonic superdirectional speaker system is provided.

According to the improved ultrasonic super-directional speaker system of the present invention and the frequency modulation processing method therefor, the improved ultrasonic super-directional speaker system which can provide cost reduction and diversification (flexibility) of the device is inexpensive and small in size, and There is an effect that it can provide a frequency modulation processing method for this.

In addition, the present invention provides an improved ultrasonic super-directional speaker system and a frequency modulation processing method therefor that can implement an algorithm for improving the processing speed through gain and unification, as well as setting and processing in a more intuitive and accessible frequency range. It can be effective.

The effects obtainable in the present invention are not limited to the above-mentioned effects, and other effects not mentioned will be clearly understood by those skilled in the art from the following description. .

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, included as part of the detailed description in order to provide a thorough understanding of the present invention, provide embodiments of the present invention and together with the description, describe the technical features of the present invention.

1 is a diagram illustrating a general speaker driver configuration using a conventional SoC and an analog input amplifier.

2 is a diagram illustrating a speaker driver configuration having an improvement of a digital speaker in a mobile phone according to the prior art.

3 is a diagram illustrating a speaker driver configuration using an external DAC according to the prior art.

4 is a diagram illustrating a configuration of a general ultrasonic superdirectional speaker.

5 is a diagram illustrating a configuration of an improved superdirectional speaker including an intermediate apparatus according to an embodiment of the present invention.

6 is a diagram illustrating a DRC function of a conventional speaker according to the prior art.

7 is a diagram illustrating a filter and an equalizer function of a conventional speaker according to the prior art.

8 is a diagram illustrating an oversampling convolution process for generating a 192 kHz signal for an ultrasonic superdirectional speaker using a conventional technology.

9 is a diagram illustrating a convolution process for Hilbert Transform for 40kHz modulation for an ultrasonic superdirectional speaker according to the prior art.

10 is a diagram illustrating a modulation processing method in a frequency domain of an ultrasonic superdirectional speaker system according to an embodiment of the present invention.

FIG. 11 is a diagram illustrating waveforms during modulation processing in a frequency domain of an ultrasonic superdirectional speaker system according to an embodiment of the present invention.

12 illustrates an improved super-directional speaker system including an intermediate device according to another embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. The detailed description, which will be given below with reference to the accompanying drawings, is intended to explain exemplary embodiments of the present invention and is not intended to represent the only embodiments in which the present invention may be practiced. The following detailed description includes specific details in order to provide a thorough understanding of the present invention. However, one of ordinary skill in the art appreciates that the present invention may be practiced without these specific details.

In some instances, well-known structures and devices may be omitted or shown in block diagram form centering on the core functions of the structures and devices in order to avoid obscuring the concepts of the present invention.

Throughout the specification, when a part is said to "comprising" (or including) a component, this means that it may further include other components, except to exclude other components unless specifically stated otherwise. do. In addition, the terms “… unit”, “… unit”, “module”, etc. described in the specification mean a unit that processes at least one function or operation, which may be implemented by hardware or software or a combination of hardware and software. have. Also, "a or an", "one", "the", and the like are used differently in the context of describing the present invention (particularly in the context of the following claims). Unless otherwise indicated or clearly contradicted by context, it may be used in the sense including both the singular and the plural.

In describing the embodiments of the present invention, if it is determined that a detailed description of a known function or configuration may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted. In addition, terms to be described below are terms defined in consideration of functions in the embodiments of the present invention, which may vary according to intentions or customs of users and operators. Therefore, the definition should be made based on the contents throughout the specification.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

1 is a diagram illustrating a general speaker driver configuration using a conventional SoC and an analog input amplifier.

In the case of a digital mobile phone speaker, the configuration generally has a digital-analog converter (DAC), which is capable of reproducing only an audio frequency range of 20 to 20 kHz, which is not suitable for application to an ultrasonic superdirectional speaker.

2 is a diagram illustrating a speaker driver configuration having an improvement of a digital speaker in a mobile phone according to the prior art.

For example, a digital cell phone can be found in a similar home appliance with a DAC in the processor and an ADC, DSP, and DAC in the speaker driver.

3 is a diagram illustrating a speaker driver configuration using an external DAC according to the prior art.

By using an external DAC, the processor does not require a DAC, and the speaker driver does not require an ADC.

4 is a diagram illustrating a configuration of a general ultrasonic superdirectional speaker.

 Ultrasonic directional speakers may also implement the system as shown in FIGS. 2 and 3. That is, as shown in FIG. 4, but as the speaker (element) is miniaturized, Amp (H / W, Speaker Driver) has a conventional general speaker function of BPF (Band-pass Filter), DRC (Dynamic Range Control), and EQ (Equalizer). ), As well as the MOD (Modulator) function, which is a modulation of the ultrasonic signal, is also implemented, so that the volume may be larger than that of a conventional speaker.

Speakers (devices) can be driven and miniaturized due to advances in device technology, but existing Amps require a new hardware (H / W) architecture. For this purpose, the functions of the existing amps on the hardware (H / W), digital modulation and amplification functions Reduction is required.

As a result, the main functions of Amp can be processed by software (S / W, DSP) so that it can be directly connected to the speaker (element) and can achieve miniaturization, convenience, flexibility and economy.

Ultrasonic speakers require modulation with signals above 40 kHz. For this purpose, DACs require a sampling frequency of at least 480 kHz, but in consumer electronics (laptops, mobiles, etc.), DAC (Digtal to Analog Converter) chips of 480 kHz or higher are not installed due to economical efficiency. not.

Therefore, in order to implement a modulation function for an ultrasonic signal and to downsize the existing Amp, a middleware & middle device for digital modulation and signal generation is required.

5 is a diagram illustrating a configuration of an improved superdirectional speaker including an intermediate apparatus according to an embodiment of the present invention.

The processor 100 processes software, digital signal processing (DSP), and provides a general core (General Core, 110) for processing general speaker functions and middleware (Middleware that can process ultrasonic signals and digital signal streams). Ultrasonic Core), 120).

In the amplifier 200, that is, the digital mobile phone, the speaker driver includes a middle device 210 that receives digital signal data and generates the pulse width modulation (PWM) in real time.

The speaker system according to the present invention implements an ultrasonic signal modulation generation part in software as well as a general speaker function in the processor 100, and the hardware 200 includes an intermediate device 210 capable of reproducing the hardware element. Because of their miniaturization and low cost, they are less expensive and smaller than conventional amplifiers, providing cost reduction and application flexibility.

On the other hand, if the middleware 120 changes the "modulation and demodulation" or the general sound source to digital signal data in the process of generating the ultrasonic signal modulation, it can be applied to the general speaker, and the left / right is divided into one general speaker, the other one It is possible to connect to the ultrasonic super-directional speakers for simultaneous playback.

6 is a diagram illustrating a DRC function of a conventional speaker according to the prior art.

7 is a diagram illustrating a filter and an equalizer function of a conventional speaker according to the prior art.

FIG. 6 illustrates a dynamic range control (DRC) as a function of an existing general speaker, and an equalizer and a filter function in FIG. 7. In the case of DRC, gain control is performed to recursive the power of the sound source amplitude of the previous state. In addition, the equalizer and filter are secondary digital systems that output 1 to 2 samples before the result, 1 to 2 samples before, and current output to the current input.

At least seven filters (BPF (1), EQ (5), LPF (1)) such as Band-pass Filter, Low-pass Filter, High-pass Filter, and EQ will be passed. There are approximately 14 samples of input and output signal data.

FIG. 8 is a diagram illustrating an Oversampling Convolution process for generating a 192 kHz signal for an ultrasonic superdirectional speaker using the conventional technique.

Ultrasonic superdirectional speakers must emit a 48 kHz sound source with a modulated signal in the ultrasonic region (40 kHz carrier). When the sine waveform is used as a reference, 8 ~ 10 samplings are required to maintain the sound source shape. Therefore, sampling corresponding to at least 8 to 10 times the maximum frequency of the sound source and carrier is required.

To do this, a modulated signal of more than 480 kHz (48 kHz x 10 times, 40 kHz x 8 times) must be transmitted, which requires oversampling and modulation operation of the sound source.

9 is a diagram illustrating a convolution process for a Hilbert Transform for 40kHz modulation for an ultrasonic superdirectional speaker according to the prior art.

The function for the ultrasonic super-directional speaker requires the oversampling convolution of FIG. 8 and the convolution processing for the modulation of FIG. 9, and as the number of operational sample data increases, the sound quality approaches a circle.

In the case of oversampling, distortion may exist as a concept of an average filter between points.

The oversampled sound source in the modulation convolution is obtained by the calculation product of the Cosine Carrier and the Sine Carrier product of the Hilbert Transform signal.

In the time-domain digital signal processing according to the prior art, as the final signal is generated only after passing through FIGS. 6, 7, 8, and 9, reverberation is left at the end as well as the initial delay.

In the conventional time domain calculation, the oversampling and modulation transformations (Hilbert Transform) and the conventional recursive digital filters for the equalizer are intertwined.

Sound quality characteristics may vary depending on the settings of the Recursive Digital Filter parameters, DRC (Dynamic Range Control) gain elements, and the number of convolutions.In addition, they are tangled with each other, making it more difficult for the general public to be able to predict the effects of parameters. it's difficult.

The technique according to the invention makes it easy for the general public to set up in terms of frequency and to monitor. In addition, it is possible to improve the processing speed by simplifying the processing algorithm into a single gain matrix finally integrated with each linear matrix gain based on the set intuitive parameter.

10 is a diagram illustrating a modulation processing method in a frequency domain of an ultrasonic superdirectional speaker system according to an embodiment of the present invention.

The frequency processing method shown in FIG. 10 is represented by a diagonal matrix for adjusting a gain of a specific frequency by performing frequency analysis on a source signal through a Discrete Fourier Transform (DFT) or a Fast Fourier Transform (FFT) matrix (constant), and an equalizer and a filter. The Hilbert Transform is shifted +/- 90 degrees according to the frequency characteristic setting, and is implemented as HFT (Hilbert Fourier Transform) constant matrix according to the components of the DFT constant matrix.

In the case of oversampling, it is possible to oversampling the frequency characteristics with a constant matrix defined by Fourier coefficients according to the number of oversampling rows of the Invert Discrete Fourier Transform (IDFT) matrix (10 times).

In case of modulation, the sum / difference can be obtained by the product of the diagonal constant matrix for sine carrier and the diagonal constant matrix for cosine carrier. As described above, if the frequency domain characteristics are intuitively set as constant matrices and diagonal matrices, the linear processing system can be expressed as one unified gain. Right) can be represented by each gain matrix.

As shown in FIG. 10, unlike the time domain method according to the conventional speaker processing, there is a DFT and IDFT processing unit. Accordingly, the recursive part of the time domain is changed to the concept of intuitive frequency control of the frequency domain.

FIG. 11 is a diagram illustrating waveforms during modulation processing in a frequency domain of an ultrasonic superdirectional speaker system according to an embodiment of the present invention.

As shown in the short-time fourier transform (STFT) of FIG. 11, monitoring is possible in terms of frequency, and intuitive frequency adjustment can be performed based on this.

Each frequency control part is set as a function parameter, and a Unified Gain matrix is derived based on the equation. This derived gain matrix can act as an open-loop system that can produce an output signal relative to the input.

On the other hand, through the parameterization of specific parameters, it is possible to extend the feedback system to define and minimize the specific cost function and to dynamically adjust the sound source of a specific frequency like the Adaptive Control system.

12 illustrates an improved super-directional speaker system including an intermediate device according to another embodiment of the present invention.

It is possible to simplify the system by applying the frequency-based algorithm of FIG. 10 to the system of FIG. 5 by implementing a general speaker processing function and an ultrasonic signal modulation function with a simplified unified gain as shown in FIG. By embedding this, the core can be shared with the Amp system (AUX → Amp) for the ultrasonic directional speaker.

Combinations of each block of the block diagrams and each step of the flowcharts attached herein may be performed by computer program instructions. These computer program instructions may be mounted on a processor of a general purpose computer, special purpose computer, or other programmable data processing equipment such that instructions executed through the processor of the computer or other programmable data processing equipment may be used in each block or flowchart of the block diagram. It will create means for performing the functions described in each step. These computer program instructions may be stored in a computer usable or computer readable memory that can be directed to a computer or other programmable data processing equipment to implement functionality in a particular manner, and thus the computer usable or computer readable memory. It is also possible for the instructions stored in to produce an article of manufacture containing instruction means for performing the functions described in each block or flow chart step of the block diagram. Computer program instructions may also be mounted on a computer or other programmable data processing equipment, such that a series of operating steps may be performed on the computer or other programmable data processing equipment to create a computer-implemented process to create a computer or other programmable data. Instructions that perform processing equipment may also provide steps for performing the functions described in each block of the block diagram and in each step of the flowchart.

In addition, each block or step may represent a portion of a module, segment or code that includes one or more executable instructions for executing a specified logical function (s). It should also be noted that in some alternative embodiments, the functions noted in the blocks or steps may occur out of order. For example, the two blocks or steps shown in succession may in fact be executed substantially concurrently or the blocks or steps may sometimes be performed in the reverse order, depending on the functionality involved.

The above description is merely illustrative of the technical idea of the present invention, and those skilled in the art to which the present invention pertains may make various modifications and changes without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention but to describe the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be interpreted by the following claims, and all technical ideas falling within the scope of the present invention should be construed as being included in the scope of the present invention.

According to the improved ultrasonic super-directional speaker system of the present invention and the frequency modulation processing method therefor, it is cheaper and smaller in size than a conventional Amp, thereby providing cost reduction and diversification of applications, and setting in a more intuitive and accessible frequency range. It can be used as a solution that provides an improved ultrasonic super-directional speaker system that can implement an algorithm that improves the processing speed through gain unification, and a frequency modulation processing method therefor. The invention is an industrially applicable invention because it is not only sufficient for the use of the related technology but also the possibility of marketing or sales of the applied device as well as practically obvious.

[Description of the code]

100: processor 110: general core 120: middleware

200: amplifier 210: intermediate device

Claims (11)

A processor including a function of a general speaker and software for generating an ultrasonic signal modulation; And And an amplifier comprising an intermediate device capable of receiving a modulated signal from said processor and reproducing it in real time. The method of claim 1, The processor, An advanced ultrasonic superdirectional speaker system characterized by a digital signal processor (DSP). The method of claim 2, The processor, An improved ultrasonic superdirectional speaker system comprising a general core for processing general speaker functions and middleware (Middleware, Ultrasonic Core) capable of processing ultrasonic signals and digital signal streams. The method of claim 2, In the middleware, in the process of generating the ultrasonic signal modulation, the general sound source is changed into digital signal data, and the left and right speakers are separated and one is connected to the general speaker and the other is connected to the ultrasonic super-directional speaker to generate a signal that is simultaneously reproduced. An improved ultrasonic super directional speaker system. The method of claim 1, The intermediate device, And receiving digital signal data from the processor to generate in real time with pulse width modulation (PWM). Displaying a source signal in a diagonal matrix for adjusting a gain of a specific frequency by performing frequency analysis through a Discrete Fourier Transform (DFT) or a Fast Fourier Transform (FFT) matrix; Representing the source signal in a Hilbert Fourier Transform (HFT) constant matrix according to the components of a DFT constant matrix; Representing the equalizer and the filter in a diagonal matrix according to the frequency characteristic setting; And Frequency modulating for the improved ultrasonic superdirectional speaker system, comprising: sum / difference / multiplying the diagonal constant matrix for sine carrier and the diagonal constant matrix for cosine carrier for modulating the signal passed through the equalizer and filter. Treatment method. The method of claim 6, In the case of oversampling, the method further comprises representing a constant matrix defined by Fourier coefficients according to the number of oversampling rows of an Invert Discrete Fourier Transform (IDFT) matrix. The method of claim 7, wherein One unified gain matrix is calculated through the constant matrix and the diagonal matrix, and the unified gain is represented by a gain matrix of left / right, such as ultrasonic and general purpose, as a linear processing system. And a frequency modulation processing method for an improved ultrasonic superdirectional speaker system. The method of claim 8, And said gain matrix acts as an open-loop system capable of producing an output signal relative to an input. The method of claim 7, wherein Through the parameterization of the specific parameters of the constant matrix and the diagonal matrix, as a feedback system for defining and minimizing the cost function of a specific performance, it is possible to dynamically adjust the sound source of a specific frequency for the improved ultrasonic super-directional speaker system for Frequency modulation processing method. A processor including a function of a general speaker and software for generating an ultrasonic signal modulation; And An amplifier including an intermediate apparatus capable of receiving a modulated signal from the processor and reproducing in real time; The ultrasonic super-directional speaker system of claim 1, wherein the modulated signal is calculated as one unified gain matrix through frequency analysis through DFT and IDFT.

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