CN207351543U - A kind of vector microphone with horn structure - Google Patents
A kind of vector microphone with horn structure Download PDFInfo
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- CN207351543U CN207351543U CN201721358634.XU CN201721358634U CN207351543U CN 207351543 U CN207351543 U CN 207351543U CN 201721358634 U CN201721358634 U CN 201721358634U CN 207351543 U CN207351543 U CN 207351543U
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Abstract
The utility model discloses a kind of vector microphone with horn structure.The utility model includes supporting rod, and acoustic pressure microphone is embedded with the upper end of the supporting rod, posted respectively in the adjacent both sides of supporting rod x to bell-mouthed sensing element and y to bell-mouthed sensing element, for measuring the vibration velocity information in each direction；The horn mouth is used for by increasing acoustic wave flow rate.The utility model improves the sensitivity of hot wire type's vector microphone with horn mouth sensitization structure.It is proposed the mirror image electric bridge pre-amplification circuit structure of the vector microphone sensing unit structure based on hot wire structure and application tandem, improve signal-to-noise ratio.
Description
Technical field
The utility model relates generally to new hot wire type's vector microphone, more particularly to a kind of to have horn mouth enhanced sensitivity knot
The vector microphone of structure.
Background technology
Acoustic measurement has extremely important effect in industry manufacture, environment measuring and national defense industry development.Acoustics
Measurement can be applied to measurement, material property measurement, auditory localization of noise and vibration etc..
Two fundamental physical quantities that sound field information is obtained in acoustic measurement are acoustic pressure and particle velocities.Sound wave is medium particle
The propagation of vibration, when the particle in fixed volume increases or decreases, can cause medium particle movement.Acoustic pressure can be regarded as wink
When one definite smaller size smaller endoplasm point quantity increase and decrease caused result.Acoustic pressure is scalar, only characterizes sound field
Dynamic pressure size at measured point, and particle vibration velocity is vector, movement velocity of the characterization particle under sound field reflecting, Yi Jiyun
The physical quantity in dynamic direction.That is, particle vibration velocity can characterize acoustic wave energy stream from what direction and towards what direction
Transmit.Acoustic pressure and particle velocity reflects the different qualities of sound field, and two parameter values can obtain complete sound field information.
Microphone used at present is generally moving-coil microphone and condenser microphone, and moving-coil microphone is to be based on
Electromagnetic induction principle, condenser microphone are to change the distance between two-plate, make capacitance that corresponding change occur.Both
Microphone all has the advantages that small, cheap etc., but both microphones are all scalar microphones, can only all be obtained
Scalar information, it is impossible to obtain Vector Message.The microphone that Vector Message can be obtained is currently pressure gradient microphone, it is to pass through
Spatially the acoustic pressure of 2 points or multiple spot is poor, i.e., produces response to acoustic pressure gradient.But indirect measurement method has certain office
It is sex-limited, two microphones to meet the consistent requirement of phase, this also allows for measurement range and is limited.In addition in indirect measurement method
Measurement frequency and the distance dependent of two microphones, the in larger distance of microphone are required in low frequency measurement, this also allows for surveying
Metering device size is difficult to realize minimize.Therefore the sensor that research can be used in directly measurement particle vibration velocity in air is very
It is necessary.Research of the domestic scholars to measuring particle vibration velocity technology in air is less, but vector microphone and vector hydrophone
There are many similarities, therefore can be with the vector sensor signal processing technology in several of water draw.
The content of the invention
It is above-mentioned to solve the purpose of this utility model is to provide a kind of vector microphone with horn mouth sensitization structure
The problem of being proposed in background.
To achieve the above object, the utility model provides following technical solution：
The utility model includes supporting rod, acoustic pressure microphone is embedded with the upper end of the supporting rod, in the phase of supporting rod
Adjacent both sides post respectively x to bell-mouthed sensing element and y to bell-mouthed sensing element, for measuring each direction
Vibration velocity information；The horn mouth is used to increase acoustic wave flow rate.
Furtherly, the circumferential direction of the supporting rod is equipped with protective cover, is to place circuit element below protective cover
Circuit board storehouse.
Furtherly, the sensing element uses two platinum filaments being arranged in parallel, the temperature difference reaction on two platinum filaments
Vibration velocity information.
Compared with background technology, the utility model has an advantageous effect in that：
The utility model improves the sensitivity of hot wire type's vector microphone with horn mouth sensitization structure.It is proposed based on heat
The vector microphone sensing unit structure of silk structure and the mirror image electric bridge pre-amplification circuit structure of application tandem, improve letter
Make an uproar ratio.
Brief description of the drawings
With reference to the accompanying drawings and examples to the utility model further instruction
Fig. 1 is the overall structure diagram of the utility model；
Fig. 2 is acoustic wave flow rate figure under 500HZ；
Fig. 3 is acoustic speed schematic diagram；
Fig. 4 is horn mouth sensitivity analogous diagram；
Fig. 5 is mirror image circuit figure；
X, Y-direction vibration velocity directivity pattern when Fig. 6 is 500HZ；
Fig. 7 is sensitivity curve figure；
In figure：1st, protective cover, 2, x to horn mouth sensing element, 3, supporting rod, 4, circuit board storehouse, 5, y it is sensitive to horn mouth
Element, 6, MEMS acoustic pressure microphone sensors.
Embodiment
The utility model is further described below in conjunction with drawings and examples
A kind of vector microphone with horn mouth sensitization structure, is to carry out vibration velocity by the temperature difference on two heated filaments
Measurement, pass through acoustic pressure microphone obtain sound pressure information.Pre-amplification circuit is designed, according to the characteristic of image current source circuit,
Realize that the resistance value for detecting two heated filaments is poor while loading same current to two heated filaments.In order to improve the sensitive of vector microphone
The accuracy of degree and measurement result, proposes to improve the sensitivity of vector microphone using horn mouth sensitization structure.
Selection designs suitable pre-amplification circuit form, on the one hand meets the temperature difference information conversion signal of heated filament,
The self noise of another aspect control circuit, meets the requirement of high s/n ratio.
Sensing unit direction vector position is put according to the angle of agreement and is sticked on supporting rod, acoustic pressure Mike's hearsay
Sensor is installed on one end of supporting rod, and amplifying circuit is placed on circuit board storehouse, is connected sensing element and circuit board using conducting wire
Connect.
Embodiment：As shown in Figure 1：The utility model includes a supporting rod 3, is embedded with the upper end of supporting rod
The MSM262S4737Z0A acoustic pressures microphone sensor 6 of MEMSensing companies production, is pasted respectively in the adjacent both sides of supporting rod
There is x to horn mouth sensing element 2 and y to horn mouth sensing element 5, be the protection with protective effect on the outside of supporting rod
1 is covered, is the circuit board storehouse 4 for placing circuit element below protective cover.
During measurement, when sound wave effect is in MEMS acoustic pressure microphone sensors, sound can directly be measured by being connected by circuit
Press information.When sound wave is applied on sensing element through horn mouth, horn mouth sensitization structure can increase through bell-mouthed sound wave
Flow velocity.Platinum filament is heated to certain temperature, and the space temperature field distribution where two platinum filaments at this time is in stable state, when sound wave is made
Used time can cause particle vibration, reduce the temperature on first heated filament of sound source, medium is obtained one by heat transfer
Point heat, the temperature on second heated filament can also reduce, but the temperature compared to first lacking of reducing.Temperature change on heated filament
So that the impedance of heated filament changes, particle vibration velocity information can be obtained by the impedance differences of two heated filaments.It is quick due to flowing through
The acoustic wave flow rate increase of sensing unit, so the sensitivity of vector microphone can be improved.Shaking for both direction can thus be measured
Fast information.
Below for the utility model is described in further detail：
1) structure design of vector microphone and making
Step 1) sensing unit key parameter design studies scheme
A kind of vector microphone with horn mouth sensitization structure, sound pressure information obtain and directly use MEMS acoustic pressure Mikes
Wind sensor measurement obtains.When measuring vibration velocity information, measuring principle is similar to airspeedometer and thermal flowmeter, transducing part by
Two parallel platinum wires are formed, and two silk threads are etched by processing technology and completed, and two ends are fixed on silicon chip electrode.Two platinum filaments were both
It is that heating unit is also sensor unit, platinum filament is heated to certain temperature, at this time the space temperature field where two platinum filaments
Distribution is in stable state, and particle vibration can be caused when sound wave effect, reduces the temperature on first heated filament of sound source, by
Heat transfer makes medium obtain a part of heat, and the temperature on second heated filament can also reduce, but the temperature compared to first reduces
Lack.Temperature change on heated filament causes the impedance of heated filament to change, and matter can be obtained by the impedance differences of two heated filaments
Point vibration velocity information.
In order to further improve sensitivity, a kind of sensing unit sensitization structure of bell-mouth structure of air, the institute of below figure 2 are designed
Show, its basic principle is the Particle Vibration Velocity near sound wave incident direction, increase sensing unit, at the beginning of finite element analysis software
Step emulation as a result, when frequency of sound wave be 500Hz, it is fast by the sound wave of heated filament when sound wave enters heated filament by horn mouth
Degree is to have just enter into horn mouth acoustic speed (about 14dB) more than 5 times, as shown in Figure 3.And analyzed, can obtained by software emulation
Gain effect at different frequencies, as shown in Figure 4, in frequency between 10Hz~10KHz, amplification factor 5.5 times with
On, it was demonstrated that gain effect is good.
Step 2) Pre-amplifier Circuit Design research approach., it is necessary to have specially after the design of hot wire type's sensing unit is completed
Particle vibration velocity information is converted to electric signal by the pre-amplification circuit of door, its purpose has at 2 points：First, heated filament is heated to necessarily
Temperature, second, the temperature difference of heated filament is converted to voltage signal, it is therefore desirable to selection designs suitable pre-amplification circuit form,
On the one hand meet that the self noise of another aspect control circuit, meets high noise by the temperature difference information conversion signal of multigroup heated filament
The requirement of ratio.The measurement of resistance difference can be usually realized plus exterior subtraction circuit using Wheatstone bridge, but due on bridge arm
The precision problem of resistance, it is difficult to ensure that flowing through one of the electric current on two heated filaments straightforward, and then introduces DC maladjustment error, in addition volume
Outer subtraction circuit is also readily incorporated noise.
The utility model designs pre-amplification circuit, realizes and two heated filaments are added according to the characteristic of image current source circuit
While carrying same current, the resistance value for detecting two heated filaments is poor.Principle is implemented as shown in figure 5, R1 and R2 is sensing in electric bridge
Two heated filaments of device, R3 and R4 are the effects for controlling electric current.Image current electric bridge is realized based on Widlar current mirror principles,
Powered by single supply and realize the measurement to resistance difference change.Electric bridge passes through two PNP transistors, two collector resistance realities
Existing.Because electric bridge is, it is necessary to heat heated filament while signal conversion is realized, by electric current heating heated filament, electric current is not
Can be excessive, therefore two resistance of emitter series connection play the role of current limliting.Assuming that when static, R=R1=R2, Δ R1=- Δs
R2, the both ends electric current of electric bridge is I, and electric bridge output AC voltage signal is
2) vector microphone performance evaluation
Step 1) directive property is tested.
According to national vector sensor calibrating standard, the directive property test of vector microphone is carried out.Test is saving metering section
Research institute's whole elimination room test is learned, vector microphone is directed at loudspeaker, by certain angle interval revolving-turret, carries out different frequencies
Directive property test under rate.As shown in fig. 6, test frequency scope is 50Hz~5kHz, frequency is given below as the finger under 500HZ
Tropism figure, it is known that, vibration velocity directive property is in ' 8 ' words, represents that directive property is good.
Step 2) sensitivity test.
According to national vector sensor calibrating standard, the sensitivity test of vector microphone is carried out.Test is saving metering section
Research institute's whole elimination room test is learned, Acoustic Wave Propagation direction is directed at the direction of vector directivity of microphone maximum, into line sensitivity
Test.As shown in fig. 7, test frequency scope is 50Hz~5kHz, sound pressure sensitivity curve is substantially steady, and sensitivity is good, two
The vibration velocity sensitivity in a direction is basically identical, and sensitivity is good.
Claims (3)
1. a kind of vector microphone with horn structure, including supporting rod, acoustic pressure wheat is embedded with the upper end of the supporting rod
Gram wind, it is characterised in that：Posted respectively in the adjacent both sides of supporting rod x to bell-mouthed sensing element and y to band horn mouth
Sensing element, for measuring the vibration velocity information in each direction；The horn mouth is used to increase acoustic wave flow rate.
A kind of 2. vector microphone with horn structure according to claim 1, it is characterised in that：The supporting rod
Circumferential direction protective cover is housed, be below protective cover place circuit element circuit board storehouse.
A kind of 3. vector microphone with horn structure according to claim 1, it is characterised in that：The sensitivity member
Part uses two platinum filaments being arranged in parallel, and the temperature difference on two platinum filaments has reacted vibration velocity information.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201721358634.XU CN207351543U (en) | 2017-10-20 | 2017-10-20 | A kind of vector microphone with horn structure |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201721358634.XU CN207351543U (en) | 2017-10-20 | 2017-10-20 | A kind of vector microphone with horn structure |
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| CN207351543U true CN207351543U (en) | 2018-05-11 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107687890A (en) * | 2017-10-20 | 2018-02-13 | 中国计量大学 | Vector microphone with horn structure |
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2017
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107687890A (en) * | 2017-10-20 | 2018-02-13 | 中国计量大学 | Vector microphone with horn structure |
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