CN110267161A - A kind of direct sound distortion antidote and device - Google Patents
A kind of direct sound distortion antidote and device Download PDFInfo
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- CN110267161A CN110267161A CN201910521645.2A CN201910521645A CN110267161A CN 110267161 A CN110267161 A CN 110267161A CN 201910521645 A CN201910521645 A CN 201910521645A CN 110267161 A CN110267161 A CN 110267161A
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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
- H04R3/00—Circuits for transducers, loudspeakers or microphones
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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
- H04R2430/00—Signal processing covered by H04R, not provided for in its groups
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Abstract
The present invention proposes that a kind of direct sound is distorted antidote and device, comprising: building orientation sonification model；Calculate the distortion rate of the model output audio；According to the distortion rate, distortion the rectification function is set；Modification processing is carried out to the distortion the rectification function, obtains pretreatment relational expression；Audio signal is modulated according to the pretreatment relational expression, obtains correction audio signal；The audio distortion rate of ultrasonic directional loudspeaker can be effectively reduced in the present invention.
Description
Technical field
The present invention relates to direct sound process field more particularly to a kind of direct sound distortion antidotes and device.
Background technique
Ultrasonic directional sound techniques be mainly used for promoted acoustic environment quality, when sound propagated as light beam.Orientation
Acoustic beam is carried by means of high frequency, and in a noisy environment, sound is still clear and legible.Therefore the quality of direct sound how is improved
Also become the matter of utmost importance of direct sound technology.Directional sound beams are readily incorporated distortion, harmonic wave using the process of air from demodulation
Distortion is directly proportional to sound source pressure, and the distortion that the bigger input of amplitude generates is bigger.Conventional method is using square root algorithm pair
Envelope signal is pre-processed.However no line harmonics can be introduced it is necessary to have infiniband by introducing square root calculation to sound source pressure
Wide ultrasonic transducer reproduces no line harmonics.And this is clearly unpractical, actually ultrasonic transducer is typically below
The direct sound of the error of 6KHz, this method processing still has biggish distortion.
Summary of the invention
In view of the above problem of the existing technology, the present invention proposes that a kind of direct sound is distorted antidote and device,
Mainly solve the problems, such as that prior art processing direct sound distortion rate is high.
To achieve the goals above and other purposes, the technical solution adopted by the present invention are as follows.
A kind of direct sound distortion antidote, comprising:
Building orientation sonification model；
Calculate the distortion rate of the model output audio；
According to the distortion rate, distortion the rectification function is set；
Modification processing is carried out to the distortion the rectification function, obtains pretreatment relational expression；
Audio signal is modulated according to the pretreatment relational expression, obtains correction audio signal.
Optionally, the orientation sonification model includes:
Integrated processor, amplifier and ultrasonic transmitter construct initial model；
Input test audio signal, obtains test result；
The initial model is adjusted according to the test result, obtains orientation sonification model.
Optionally, voice modulation uses quadrature amplitude modulation, comprising:
Amplitude modulation is carried out to audio, obtains am signals；
The phase difference that the am signals and the distortion the rectification function are arranged is 90 degree, carries out quadrature amplitude tune
System.
Optionally, the acquisition pretreatment relational expression includes:
Construct the primary wave acoustic pressure relational expression of audio signal；
The acoustic pressure relational expression of secondary wave is constructed according to the acoustic pressure of the first harmonic；
Using the acoustic pressure relational expression of secondary wave described in the model solution of the far field Bai Keta, secondary wave acoustic pressure and distortion factor are obtained
Relational expression；
Taylor series expansion is carried out to the relational expression of the distortion factor, obtains the pretreatment relational expression.
Optionally, it is described audio signal is modulated after, to the audio signal carry out equilibrium treatment, comprising:
By the correction audio signal input equalizer；The balanced device is for filtering out the high pitch beyond given threshold, institute
Stating balanced device includes binary system finite impulse filters.
A kind of direct sound distortion calibration device, comprising:
Orient sonification model；
Computing module is corrected, for calculating the distortion rate of the model output audio, and is arranged according to the distortion rate and is lost
True the rectification function；
Preprocessing module obtains pretreatment relational expression for carrying out modification processing to the distortion the rectification function；
Modulation module obtains correction audio signal for being modulated according to the pretreatment relational expression to audio signal.
Optionally, the orientation sonification model includes: processor, amplifier and ultrasonic transmitter.
Optionally, the processor includes fixed DSP processor, float-point DSP processor or single-chip microcontroller.
Optionally, the preprocessing module includes:
Acoustic pressure relationship structural unit, for constructing the primary wave acoustic pressure relational expression of audio signal, and according to described primary humorous
The acoustic pressure relational expression of the acoustic pressure building secondary wave of wave；
It is distorted the rectification function structural unit, for the acoustic pressure relationship using secondary wave described in the model solution of the far field Bai Keta
Formula obtains the relational expression of secondary wave acoustic pressure and distortion factor；
Variant unit carries out Taylor series expansion for the relational expression to the distortion factor, obtains the pretreatment and closes
It is formula.
Optionally, described device further includes balanced device, and for filtering out the high pitch for exceeding given threshold, the balanced device includes
Binary system finite impulse filters.
As described above, a kind of direct sound of the present invention is distorted antidote, have the advantages that.
Audible sound sound quality, adjustment carrier signal and then less air are improved from demodulation distortion by pretreatment；By pre-
Processing avoids out the requirement that radical sign modulation scheme provides a loan to ultrasonic transmitter, solves what ultrasonic transmitter loan caused
Problem of dtmf distortion DTMF.
Detailed description of the invention
Fig. 1 is the flow chart of the direct sound distortion antidote in one embodiment of the invention.
Fig. 2 is the module map of the direct sound distortion apparatus for correcting in one embodiment of the invention.
Specific embodiment
Illustrate embodiments of the present invention below by way of specific specific example, those skilled in the art can be by this specification
Other advantages and efficacy of the present invention can be easily understood for disclosed content.The present invention can also pass through in addition different specific realities
The mode of applying is embodied or practiced, the various details in this specification can also based on different viewpoints and application, without departing from
Various modifications or alterations are carried out under spirit of the invention.It should be noted that in the absence of conflict, following embodiment and implementation
Feature in example can be combined with each other.
It should be noted that illustrating the basic structure that only the invention is illustrated in a schematic way provided in following embodiment
Think, only shown in schema then with related component in the present invention rather than component count, shape and size when according to actual implementation
Draw, when actual implementation kenel, quantity and the ratio of each component can arbitrarily change for one kind, and its assembly layout kenel
It is likely more complexity.
Direct sound is carried to low frequency audible sound on ultrasonic wave high frequency carrier, and the good direction of ultrasonic wave is utilized
Property, directionally send ultrasonic carrier signal in air, recycle air from demodulation ability, filter out radio-frequency component, also
Former audible sound.However, air can introduce distortion from demodulation, in order to solve problem of dtmf distortion DTMF, this programme proposes a kind of orientation sound
Sound is distorted antidote and device.
Fig. 1 is the flow chart that direct sound of the present invention is distorted antidote.
The direct sound distortion antidote includes step S01-S04:
In step S01, building orientation sonification model:
At ultrasonic directional sound speaker (Ultrasonic Directional Sound Speaker, abbreviation UDSS)
Middle integrated processor, amplifier and ultrasonic transmitter constitute orientation sonification model.Processor may include fixed DSP, floating-point
DSP and PC etc..Here by taking fixed DSP as an example, real time audio processing algorithm is realized on DSP.After input test audio is to integrating
Orientation sonification model carry out functional test, and the result that is collected into of test is used to adjust orientation sonification model, to improve
The stability of UDSS.
Since the dynamic range of UDSS is limited, when incoming level is too low or excessively high, UDSS, which will generate to be difficult to listen, distinguishes defeated
Out with serious distortion.In one embodiment, dynamic range control is set on a processor.By taking DSP as an example, when incoming level is big
When 3677, the realization gain match effect using the dynamic range control of simulation softward simulation is good；And between 0 to 3677
Signal level, especially for the 3D sound in 0 to 3677 ranges, DSP is provided with noise in this signal level
Threshold value can reduce the quality of 3D sound.Therefore the present embodiment eliminates the noise threshold on DSP when carrying out dynamic range control
Value eliminates the noise introduced by noise threshold.
In step S02, computation model exports the distortion rate of audio:
In order to reduce distortion, first have to carry out quantification treatment to distortion.It can be lost using total harmonic distortion (THD) and intermodulation
Very (IMD) two kinds of measurement methods carry out distortion measurement.Total harmonic distortion refers to output than inputting the harmonic having more.And intermodulation
Distortion refers to two or more frequency signals by generating beat after amplifier or loudspeaker or constituting new frequency component.For
THD measurement distortion, expression formula can be used in unifrequency ω 1 are as follows:
Wherein T1 and Ti is respectively i=2,3 ..., n, fundamental frequency omega 1 and its each harmonic.It, can for double frequency ω 1 and ω 2
It is measured and is distorted using second order IMD, expression formula are as follows:
Wherein, DωAnd VdRespectively m-Acetyl chlorophosphonazo component of the demodulated signal at frequency and amplitude.
In step S03, distortion the rectification function is arranged according to distortion rate:
According to the distortion the rectification function for the distortion data building orientation sonification model being calculated.It can be according to distortion data
Recurrence calculating is carried out, the relationship of distortion with input signal is obtained.
In step S04, modification processing is carried out to the distortion the rectification function, obtains pretreatment relational expression:
Construct the primary wave acoustic pressure relational expression of the modulated signal；
In order to make UDSS generate audio, usually modulated the audio signal on ultrasonic carrier by amplitude modulation, into width excessively
After degree modulation, acoustic pressure of the primary wave on axis at distance sources x are as follows:
Wherein P0For main wave-amplitude, m is modulation index, and g (t) is input signal, and α is absorption coefficient, ωcFor carrier frequency.
The acoustic pressure relational expression of secondary wave is constructed according to the acoustic pressure of the first harmonic.
Due to consideration that the audio that UDSS is issued is nonlinear.For nonlinear properties, the far field Bai Keta can be used
Model carries out the approximation of non-linear audio, the far-field array response of UDSS is predicted, to simplify nonlinear problem.It is remote according to Bai Keta
The pressure p for the demodulated signal that field model obtains2(t) or audible difference frequency is flat with amplitude modulation ultrasonic carrier envelope along axis direction is propagated
The second time derivative of side is directly proportional, expression formula are as follows:
Wherein, β is air nonlinearity coefficient, p in formula0For ultrasonic sound source pressure magnitude, a is sound source radius, ρ0It is close for environment
Degree, c0For the small signal velocity of sound, z is beam axis coordinate, α0For air absorption coefficient, τ is lag time t-z/c0, E (τ) is super
The amplitude of sound carrier modulation envelope function.
Using demodulated signal acoustic pressure relational expression described in the model solution of the far field Bai Keta, obtains demodulated signal acoustic pressure and distortion is
Several relational expressions；
Wherein g " (t) is that the second order of input signal is reciprocal.In general, can be carried out to envelope function E (τ) to eliminate distortion
Open radical sign operation.By opening the available unlimited subharmonic of radical sign operation, ideally, anti-mistake carried out by the unlimited subharmonic of factor
True strength element, can eliminate demodulated signal and be distorted in air.And in practical application, the bandwidth of ultrasonic transmitter is usually arrived 1
6Hz is unable to satisfy the requirement of unlimited subharmonic, it will causes serious distortion.
In one embodiment, in order to avoid opening radical sign operation, Taylor series expansion is carried out to distortion factor relational expression；By institute
Taylor series expansion is stated to be introduced into the modulated signal.Use gD(t) Taylor seriesTo replace gD(t):
Wherein q is indicatedTaylor series item number.With the items in Taylor expansionReplace gD
(t), then gT(t) become:
The wireless harmonic problem that Taylor expansion can be drawn because opening radical sign operation is carried out, so that ultrasonic transmitter is not required to
There is wireless bandwidth.Distortion can be effectively reduced.
In step S05, audio signal is modulated according to the pretreatment relational expression, obtains correction audio signal.
Since traditional amplitude modulation will generate the demodulated signal of enough sound pressure levels, very high modulation index is needed, and is adjusted
The increase of index processed will lead to the increase of total harmonic distortion.Therefore, the present embodiment introduces distortion school on the basis of amplitude is modulated
It just, will be on the amplitude of audible signal God knows ultrasonic carrier by the way of quadrature amplitude modulation.Referring to Fig. 2, setting
Am signals are gAM(t)=g1(t)sin(ω0T), then quadrature amplitude modulation signal gT(t) it may be expressed as:
Wherein, g1 (t) indicates the amplitude of am signals, and gD (t) indicates distortion the rectification function.
By the signal input equalizer Jing Guo quadrature amplitude modulation, equilibrium treatment is carried out.In one embodiment, balanced device can
To be designed based on binary system finite impulse filters, finite impulse filters belong to the mature prior art, no longer superfluous here
It states.Balanced device is mainly used for filtering out the high-frequency impulse in the signal through ovennodulation, prevents high-frequency impulse from causing treble distortion.
By being exported by amplifier to ultrasonic transmitter after overcorrection, sent directionally to by ultrasonic transmitter
In air.
Referring to Fig. 2, the present embodiment provides a kind of direct sounds to be distorted apparatus for correcting, comprising: orientation sonification model, correction
Computing module, modulation module and preprocessing module.Due to the technical principle of this system embodiment and the skill of preceding method embodiment
Art principle is similar, therefore no longer does repeatability to same technical detail and repeat.Orientation sonification model 10 is for executing aforementioned side
Step S01 in method embodiment, correction computing module 11 is used to execute the step S02 and S03 in preceding method embodiment, pre- to locate
Reason module 12 is used to execute the step S04 in preceding method embodiment, and modulation module 13 is for executing in preceding method embodiment
Step S05.
It will be appreciated by those skilled in the art that the division of the modules in Fig. 2 embodiment is only a kind of logic function
Division, can completely or partially be integrated on one or more physical entities in actual implementation.And these modules can be whole
It is realized, can also be all realized in the form of hardware by way of processing element calls with software, it can be logical with part of module
Crossing processing element calls the form of software to realize that part of module passes through formal implementation of hardware.Such as correction computing module can be with
For the processing element individually set up, it also can integrate and realized in some chip.
In conclusion a kind of direct sound distortion antidote of the present invention and device, introduce Taylor series, avoid ultrasonic wave
The distortion that the limitation of transmitter bandwidth causes；Balanced device is introduced, the high-frequency impulse in adjustment signal makes signal waveform become more flat
It is smooth, prevent high-frequency impulse from causing treble distortion.So the present invention effectively overcomes various shortcoming in the prior art and has height
Value of industrial utilization.
The above-described embodiments merely illustrate the principles and effects of the present invention, and is not intended to limit the present invention.It is any ripe
The personage for knowing this technology all without departing from the spirit and scope of the present invention, carries out modifications and changes to above-described embodiment.Cause
This, institute is complete without departing from the spirit and technical ideas disclosed in the present invention by those of ordinary skill in the art such as
At all equivalent modifications or change, should be covered by the claims of the present invention.
Claims (10)
1. a kind of direct sound is distorted antidote characterized by comprising
Building orientation sonification model；
Calculate the distortion rate of the model output audio；
According to the distortion rate, distortion the rectification function is set；
Modification processing is carried out to the distortion the rectification function, obtains pretreatment relational expression；
Audio signal is modulated according to the pretreatment relational expression, obtains correction audio signal.
2. direct sound according to claim 1 is distorted antidote, which is characterized in that the orientation sonification model packet
It includes:
Integrated processor, amplifier and ultrasonic transmitter construct initial model；
Input test audio signal, obtains test result；
The initial model is adjusted according to the test result, obtains orientation sonification model.
3. direct sound according to claim 1 is distorted antidote, which is characterized in that voice modulation uses quadrature amplitude
Modulation, comprising:
Amplitude modulation is carried out to audio, obtains am signals；
The phase difference that the am signals and the distortion the rectification function are arranged is 90 degree, carries out quadrature amplitude modulation.
4. direct sound according to claim 3 is distorted antidote, which is characterized in that the acquisition pre-processes relational expression
Include:
Construct the primary wave acoustic pressure relational expression of audio signal；
The acoustic pressure relational expression of secondary wave is constructed according to the acoustic pressure of the first harmonic；
Using the acoustic pressure relational expression of secondary wave described in the model solution of the far field Bai Keta, the pass of secondary wave acoustic pressure and distortion factor is obtained
It is formula；
Taylor series expansion is carried out to the relational expression of the distortion factor, obtains the pretreatment relational expression.
5. direct sound according to claim 1 is distorted antidote, which is characterized in that described to be adjusted to audio signal
After system, equilibrium treatment is carried out to the audio signal, comprising:
By the correction audio signal input equalizer；The balanced device is described equal for filtering out the high pitch beyond given threshold
Weighing apparatus includes binary system finite impulse filters.
6. a kind of direct sound distortion calibration device characterized by comprising
Orient sonification model；
Computing module is corrected, is rectified for calculating the distortion rate of the model output audio, and according to distortion rate setting distortion
Positive function；
Preprocessing module obtains pretreatment relational expression for carrying out modification processing to the distortion the rectification function；
Modulation module obtains correction audio signal for being modulated according to the pretreatment relational expression to audio signal.
7. direct sound according to claim 6 is distorted apparatus for correcting, which is characterized in that the orientation sonification model packet
It includes: processor, amplifier and ultrasonic transmitter.
8. direct sound according to claim 7 is distorted apparatus for correcting, which is characterized in that the processor includes fixed point
Dsp processor, float-point DSP processor or single-chip microcontroller.
9. direct sound apparatus for correcting according to claim 6, which is characterized in that the preprocessing module includes:
Acoustic pressure relationship structural unit, for constructing the primary wave acoustic pressure relational expression of audio signal, and according to the first harmonic
The acoustic pressure relational expression of acoustic pressure building secondary wave；
It is distorted the rectification function structural unit, for the acoustic pressure relational expression using secondary wave described in the model solution of the far field Bai Keta, is obtained
To the relational expression of secondary wave acoustic pressure and distortion factor；
Variant unit carries out Taylor series expansion for the relational expression to the distortion factor, obtains the pretreatment relational expression.
10. direct sound according to claim 6 is distorted antidote, which is characterized in that further include balanced device, for filtering
Except the high pitch for exceeding given threshold, the balanced device includes binary system finite impulse filters.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN110837791A (en) * | 2019-11-02 | 2020-02-25 | 山东科技大学 | Sound velocity profile inversion method based on over-complete dictionary |
| CN114360560A (en) * | 2022-01-17 | 2022-04-15 | 随锐科技集团股份有限公司 | Speech enhancement post-processing method and device based on harmonic structure prediction |
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