CN106375908A - Method for synthesizing ultrasonic wave into audible sound and controlling range of audible space - Google Patents

Abstract

The invention discloses a method for synthesizing an ultrasonic wave into an audible sound and controlling a range of an audible space. According to the high directivity of the ultrasonic wave, audios emitted by a speaker can travel in a straight line like light from a flashlight; therefore, the invention adopts a carrier technology and a side band wave technology to change the principle of an original technology of multiplying a high frequency ultrasonic wave by a target audible sound into a principle of adding two beams of ultrasonic waves; through computer programming, specified audios are changed into two beams of ultrasonic waves, that is, a carrier wave and a side band wave, and the carrier wave and the side band wave are respectively emitted by two ultrasonic loudspeakers firstly, and then synthesized in air; separate carrier wave and side band wave are inaudible; therefore, eventually the effect that only a small part of the designated area of sound is audible can be achieved, and the effect that the sound can be listened by only one person in the case of placing the speaker at the outside, and other persons are not disturbed can be achieved.

Description

A kind of by ultrasound synthesis sub-audible sound and the method that controls audible spatial dimension

Technical field

The invention belongs to physical field, it is related to voice synthesis and in particular to one kind is by ultrasound synthesis sub-audible sound And the method controlling audible spatial dimension.

Background technology

(1) limitation of ventional loudspeakers

Common speaker, when putting outside, because the transmission of audible sound sound wave aerial spherical wave is so that in sound Sound decay to minimum before, can hear in whole space.This makes among space, whether specifying for speaker Hearer can hear the sound of speaker.Although having invented earphone to tackle this sound pollution problem, but still there is not side Just wear the situation of earphone.

(2) limitation of parametric loudspeaker (parametric loudspeaker)

The problem excessive for tackling the audible space of ventional loudspeakers, last century starts scientist and begins one's study and will spread sphere Ripple is reduced into focusing on the probability of sound column, has then derived a large amount of researchs for focusing sound.Wherein more famous and more It is successfully that the U.S. continues about the research of parametric array loudspeaker with Japan.Existing parametric array loudspeaker is generally adopted by high frequency The music of complicated wave form is added on high frequency carrier using multiplier by sound amplitude modulated technique, such as Fig. 1, as shown in Figure 2.

Based on the high directivity of ultrasound wave, parametric array loudspeaker can make audio frequency directional propagate.Reach audio frequency directional Effect, is therefore called directional sound again.But because ultrasound wave is easy to the feature reflecting so that current parametric array loudspeaker is narrow Little indoor reflection is serious, and audible space increases, and using the feature losing its direction propagation, parametric array loudspeaker is audible simultaneously Scope is one to start from speaker until sound attenuating is to non-audible unilateral infinitely long cylinder so that body in specified hearer Acoustic is remained to, as shown in Figure 3 after predecessor.The practical neck of audio frequency directional technology because such defect exists, is greatly reduced Domain.In addition to the military version audio frequency directional device using in open field, the audio frequency directional of the interior use on current market is raised More than sound device by the way of Vertical Launch, as shown in Figure 4；And the mode of Vertical Launch, it is not only due to the roundtrip shadow of sound Ring tone color, and the position that speaker is laid also has been restricted significantly.

Content of the invention

For the problems referred to above, the present invention propose a kind of by ultrasound synthesis sub-audible sound and control the side of audible spatial dimension Method, on the basis of common audio amplifier and parametric array loudspeaker, reduces the scope in audible space further, by the cylinder of endless Body is reduced into the spheroid of limited bulk, solves original parametric array loudspeaker and can exceed asking of expected value due to reflecting the range of audibility Topic.

A kind of by ultrasound synthesis sub-audible sound and the method that controls audible spatial dimension, realized by following step:

Step 1: install ultrasound wave ring energy device in shell, constitute speaker.

Step 2: speaker two in selecting step 1, it is symmetrical arranged, and so that the direction of the launch of two speakers is intersected.

Step 3: fixed frequency f is play by a speaker₁Sine wave, another speaker broadcasting frequency f simultaneously₂'s Ultrasound wave music, and f₂Frequency close to f₁Frequency；Thus in the intersecting region between two speakers, can collect Stable frequency f₃=| f₁-f₂| audible music.

It is an advantage of the current invention that:

1st, the present invention by ultrasound synthesis sub-audible sound and the method that controls audible spatial dimension, can control audible space model Enclose, sound just can be heard in the position only meeting certain condition with audio amplifier distance；

2nd, the present invention is by ultrasound synthesis sub-audible sound and the method that controls audible spatial dimension, by the big model of common audio amplifier Enclose audible space, and the audible space of cylinder of common directional sound, be reduced to audible (or one very little of title of one of space point Spherical spaces), be avoided that the noise jamming of unnecessary sound field, can be applicable to square dance, market advertising display etc.；

3rd, the present invention is by ultrasound synthesis sub-audible sound and the method that controls audible spatial dimension, with common audio amplifier or orientation Audio amplifier is different, and sound position the strongest is no longer apart from the nearest place in audio amplifier position, but the space point specified；Therefore, Can structural physical stereophonic field in space, put outside audio amplifier and can reach earphone general " seemingly someone speaks in one's ear on your left side " Effect.

Brief description

Fig. 1 is the multiplicative principle of parametric array loudspeaker；

Fig. 2 is the mlultiplying circuit figure of parametric array loudspeaker；

Fig. 3 is parametric array loudspeaker reflecting effect schematic diagram；

Fig. 4 puts limitation for parametric array loudspeaker

Fig. 5 is that the present invention by ultrasound synthesis sub-audible sound and controls the method schematic of audible spatial dimension；

Fig. 6 is ultrasonic transducer arrangement mode schematic diagram in the inventive method；

When Fig. 7 is for ultrasonic transducer transmitting 40khz ultrasound wave, acoustic wave energy characteristic schematic diagram.

Specific embodiment

Below in conjunction with the accompanying drawings the present invention is described in further detail.

The present invention a kind of by ultrasound synthesis sub-audible sound and the method that controls audible spatial dimension, as shown in figure 5, specifically Method is as follows:

Step 1: ultrasonic transducer is installed in arrangement；

As shown in fig. 6, ultrasonic transducer is arranged in close hexagon ultrasound transducer array, 5, every side, Gu Dingan County is loaded on the corresponding installation in the hole opening up on shell, constitutes speaker.In the present invention, ultrasonic transducer adopts tct40- 16r/t, its each parameter is respectively as follows:

Nominal frequency: 40khz；Acoustic pressure in transmission at10v (0db=0.02mpa): >=110db；Static capacity at1khz, < 1v (pf): 2000 ± 30%；Ultrasonic transducer profile is cylinder, and is provided with positive and negative polarities pin, as shown in fig. 7, ultrasonic During wave transducer transmitting 40khz ultrasound wave, within acoustic wave energy is concentrated mainly on positive and negative 30 degree of the direction of the launch, there is ultrasound wave collection Middle convergence, be difficult spread characteristic

Step 2: locus design；

Using the speaker obtaining in two steps 1, order is respectively speaker a and speaker b, and it is fixed to be supported by support Position, and so that speaker a is symmetrical arranged with speaker b, so that speaker a and the direction of the launch of speaker b is intersected, angle is preferred simultaneously For 90 °, as shown in Figure 5.Because the convergence of ultrasound wave is by force so that the ultrasonic transducer in speaker a and Yang Sheng device b is sent out The ultrasound wave penetrated produces an intersection region, is zone of audibility, can be recombined in this region sound.

Step 3: play music；

Fixed frequency f is synchronously play by each ultrasonic transducer in speaker a by speaker a₁Sine wave (carrier wave), Simultaneously by each ultrasonic transducer synchronization broadcasting frequency f in speaker b₂Ultrasound wave music (side band ripple), f₂For f₁Frequency nearby Rate value.Thus in the intersection region between two speakers, stable frequency f can be collected₃=| f₁-f₂| audible original Music.F is chosen in the present invention₁=40khz, f₂=f1 ± 10khz, may conform to the physical characteristics of current ultrasonic element, at this Under frequency, the performance of ultrasonic element is best.If the frequency range of ultrasonic element is very big or customizable, f₁Can be higher, f₁Higher Then the directivity of ultrasound wave is stronger, and audible spatial dimension just can be more accurate, is not a unmodifiable value.

The ultrasound wave music that in above-mentioned speaker b, each ultrasonic transducer is synchronously play, needs by former sound to be played Pleasure is converted to by following manner, as shown in figure 5, specific as follows:

1) the former music of normal frequency playing need, discrete disassembles the synthesis becoming the n different single-frequency sound of amplitude；Its In, n is positive integer, and span is 1～30, requires specifically to determine according to the different of quality.

2) add f by unified for the frequency of each single-frequency sound in step a₁.

3) each single-frequency sound increasing after frequency is recombined, form one section of multifrequency complexity ultrasound wave audio frequency, that is, walk The ultrasound wave music that in rapid 3, speaker b is play.

Claims (6)

1. a kind of by ultrasound synthesis sub-audible sound and control audible spatial dimension method it is characterised in that: by following steps Rapid realization:

Step 1: install ultrasound wave ring energy device in shell, constitute speaker；

Step 2: speaker two in selecting step 1, it is symmetrical arranged, and so that the direction of the launch of two speakers is intersected；

Step 3: fixed frequency f is play by a speaker₁Sine wave, another speaker broadcasting frequency f simultaneously₂Ultrasonic Boeing is found pleasure in, and f₂Frequency close to f₁Frequency；Thus in the intersecting region between two speakers, can collect stable Frequency f₃=| f₁-f₂| audible music.

2. as claimed in claim 1 a kind of by ultrasound synthesis sub-audible sound and the method that controls audible spatial dimension, its feature It is: in step 1, ultrasonic transducer is arranged in close hexagon ultrasound transducer array, is fixedly installed on shell The corresponding installation in the hole opening up.

3. as claimed in claim 1 a kind of by ultrasound synthesis sub-audible sound and the method that controls audible spatial dimension, its feature It is: ultrasonic transducer adopts tct40-16r/t, nominal frequency: 40khz；Acoustic pressure in transmission at10v (0db=0.02mpa): ≥110db；Static capacity at1khz, < 1v (pf): 2000 ± 30%.

4. as claimed in claim 1 a kind of by ultrasound synthesis sub-audible sound and the method that controls audible spatial dimension, its feature It is: in step 2, the direction of the launch angle of two speakers is 90 °.

5. as claimed in claim 1 a kind of by ultrasound synthesis sub-audible sound and the method that controls audible spatial dimension, its feature It is: in step 3, in the present invention, choose f₁=40khz, f₂=f₁±10khz.

6. as claimed in claim 1 a kind of by ultrasound synthesis sub-audible sound and the method that controls audible spatial dimension, its feature It is: the ultrasound wave music in step 3, it is converted to by following manner by former music to be played:

1) the former music of normal frequency playing need, discrete disassembles the synthesis becoming the different single-frequency sound of amplitude；

2) add f by unified for the frequency of each single-frequency sound in step a₁.

3) each single-frequency sound increasing after frequency is recombined, form ultrasound wave music.