CN202488715U - Detector of microphone high sound pressure-phase-shift characteristics - Google Patents
Detector of microphone high sound pressure-phase-shift characteristics Download PDFInfo
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- CN202488715U CN202488715U CN 201220063970 CN201220063970U CN202488715U CN 202488715 U CN202488715 U CN 202488715U CN 201220063970 CN201220063970 CN 201220063970 CN 201220063970 U CN201220063970 U CN 201220063970U CN 202488715 U CN202488715 U CN 202488715U
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Abstract
The utility model provides a detector of microphone high sound pressure-phase-shift characteristics. A variable cross-section confined space is formed by an equal-phase coupled cavity, a variable cross-section reflection end cover, a standing wave tube and a bottom reflection end cover; a speaker in the standing wave tube is connected with a power amplifier, the power amplifier is connected with a signal source, the signal source is connected with a computer; a reference microphone and a revised microphone are respectively arranged on two side walls of the equal-phase coupled cavity; and the reference microphone and the revised microphone are further connected with a signal amplifier which is connected with the computer. By means of the detector, feedback control of an acoustic pressure level in the equal-phase coupled cavity can be achieved, a sound pressure signal which is 160 decibels in an upper limit and 94 decibels in a lower limit can be produced, and a degree of distortion is less than 1 percent. In addition, a revising problem of non-linear phase-shift of sensitivity of a microphone under the circumstance of a high acoustic pressure level (more than 140 decibels) is solved.
Description
Technical field
The utility model relates to the acoustic metrology technical field, is specifically related to a kind of checkout gear of microphone high sound pressure-phase-shift characterisitc.
Background technology
Microphone is claimed " acoustic-electrical transducer " again, is transducer crucial in the acoustical testing, is the converting means that converts acoustical signal in the air into the signal of telecommunication, and its sensitivity has phase characteristic, is commonly called phse sensitivity.In recent years along with the modern acoustics measuring technology constantly develops; Acoustical holography analysis, sounding target localization, sounding accident analysis, the sound new technologies such as coupling analysis of shaking have appearred; These technology all need be used the phse sensitivity of microphone; Be mainly used in acoustical testing work such as noise source positioning analysis, remote acoustic target identification, engine noise failure diagnosis, rocket launching on-the-spot test; The sound pressure level of these test environments has covered the dynamic range to 165dB from 80dB, and the nonlinear phase offset characteristic can appear in microphone under high sound pressure level (more than the 140dB) environment, and the microphone phase error of introducing is the main source that influences the measurement result accuracy.
To the microphone phase error of introducing, existing collimation technique adopts pressure field coupling cavity relative phase calibration steps, can under the environment of 124dB sound pressure level, calibrate the microphone phse sensitivity, and the calibration structure principle is as shown in Figure 1.Signal source 3 output one fixed frequency (250Hz) normal signals; In active coupling cavity 2, produce the pressure field sound pressure signal of this frequency; The bulk of active coupling cavity 2 requires less than 1/20 of wavelength; The sound pressure level that produces is no more than 124dB, and proofing microphone 1 and standard microphone 4 are installed in active coupling cavity 2 two ends, makes these two microphones amplitude equiphase sound pressure signal such as experience; Be transformed to the signal of telecommunication through measuring amplifier 7; Data acquisition card 6 converts analog electrical signal A/D into digital data transmission and handles for computer 5, and the phase difference that computer 5 is calculated two path signal through the cross-spectrum analysis meter can calculate the phase difference of seized microphone relative standard microphone under this frequency.But, under high sound pressure level (more than the 140dB) environment, adopt this method again to phase alignment, can produce the difficult problem of microphone phse sensitivity nonlinear phase shift, can't realize the microphone phase alignment.
Summary of the invention
The utility model is for solving the calibration problem of microphone phse sensitivity nonlinear phase shift under high sound pressure level (more than the 140dB) environment; A kind of checkout gear of microphone high sound pressure-phase-shift characterisitc is proposed; It uses the standing-wave sound field principle to make sound source reach the high sound pressure of 160dB; And the distortion factor＜1% can be realized the phase-shift characterisitc calibration of microphone phse sensitivity under the high sound pressure environment by the equiphase coupling cavity.
Realize the technical scheme of the utility model purpose: a kind of checkout gear of microphone high sound pressure-phase-shift characterisitc, it comprises an equiphase coupling cavity that falls " U " shape, the equiphase coupling cavity center of being fixedly connected on has the variable cross-section reflection end side of covering of through hole; The internal diameter of equiphase coupling cavity equates that with the through hole internal diameter of variable cross-section reflection end cap the external diameter of equiphase coupling cavity is less than the external diameter of variable cross-section reflection end cap; The top of standing wave tube is fixedly connected on variable cross-section reflection end cap below, and the bottom of standing wave tube is fixedly connected on the bottom reflection end cap; The internal diameter of standing wave tube is greater than the through hole internal diameter of variable cross-section reflection end cap, and the external diameter of standing wave tube equals the external diameter of variable cross-section reflection end cap; Form a variable cross-section confined space through equiphase coupling cavity, variable cross-section reflection end cap, standing wave tube, bottom reflection end cap;
In standing wave tube, above the bottom reflection end cap, be provided with loud speaker; Loud speaker connects power amplifier through lead-out wire, and power amplifier also connects signal source, and signal source connects computer again; Wherein, connection power amplifier in computer control signal source drives loud speaker and sends the normal acoustic signals; The normal acoustic signals that loud speaker sends repeatedly reflects to form the high sound pressure stationary field in above-mentioned variable cross-section confined space;
The symmetric position place opens mouth in the two side of equiphase coupling cavity, is installed in passage port respectively with reference to microphone and proofing microphone; Also be connected signal amplifier through lead-out wire respectively with reference to microphone with proofing microphone, signal amplifier connects computer again; Wherein, the sound pressure amplitude with reference in the microphone monitoring equiphase coupling cavity passes to computer through signal amplifier with real-time sound pressure amplitude, again by the sound pressure amplitude in computer control signal source and then the control equiphase coupling cavity; Can obtain microphone high sound pressure-phase-shift characterisitc through the witness mark microphone with the phase difference of proofing microphone under different sound pressure levels.
The checkout gear of aforesaid a kind of microphone high sound pressure-phase-shift characterisitc, the external diameter of its described equiphase coupling cavity are 1/2～1/3 times of external diameter of variable cross-section reflection end cap; The internal diameter of described standing wave tube is 2～3 times of through hole internal diameter of variable cross-section reflection end cap.
The checkout gear of aforesaid a kind of microphone high sound pressure-phase-shift characterisitc; The normal acoustic signals that its described loud speaker sends repeatedly reflects to form the high sound pressure stationary field in the variable cross-section confined space; Sound pressure level can reach 94～160dB, the sound wave distortion factor＜1% in this stationary field.
The effect of the utility model is: the checkout gear of the described a kind of microphone high sound pressure-phase-shift characterisitc of the utility model; Can realize the FEEDBACK CONTROL of sound pressure level in the equiphase coupling cavity; Upper limit 160dB can take place, the sound pressure signal of lower limit 94dB, and the distortion factor＜1%; Can solve the calibration problem of sensitivity of microphone nonlinear phase shift under high sound pressure level (more than the 140dB) environment.
Description of drawings
Fig. 1 is for adopting pressure field coupling cavity relative phase calibration steps;
Fig. 2 is the checkout gear structural representation of the described a kind of microphone high sound pressure-phase-shift characterisitc of the utility model;
Among the figure: 1. proofing microphone; 2. active coupling cavity; 3. signal source; 4. standard microphone; 5. computer; 6. data acquisition card; 7. measuring amplifier; 8. with reference to microphone; 9. equiphase coupling cavity; 10. variable cross-section reflects end cap; 11. standing wave tube; 12. loud speaker; 13. bottom reflection end; 14. power amplifier; 15. signal amplifier.
Embodiment
Further describe below in conjunction with accompanying drawing and specific embodiment checkout gear the described a kind of microphone high sound pressure-phase-shift characterisitc of the utility model.
As shown in Figure 2, the checkout gear of the described a kind of microphone high sound pressure-phase-shift characterisitc of the utility model, it comprises an equiphase coupling cavity 9 that falls " U " shape, equiphase coupling cavity 9 centers of being fixedly connected on have variable cross-section reflection end cap 10 tops of through hole; The internal diameter of equiphase coupling cavity 9 equates that with the through hole internal diameter of variable cross-section reflection end cap 10 external diameter of equiphase coupling cavity 9 is 1/2～1/3 times of the external diameter (for example: 1/2 times or 1/3 times) of variable cross-section reflection end cap 10.The top of standing wave tube 11 is fixedly connected on variable cross-section reflection end cap 10 belows, and the bottom of standing wave tube 11 is fixedly connected on the bottom reflection end 13; The internal diameter of standing wave tube 11 is 2～3 times (for example: 2 times or 3 times) of the through hole internal diameter of variable cross-section reflection end cap 10, and the external diameter of standing wave tube 11 equals the external diameter of variable cross-section reflection end cap 10.Through equiphase coupling cavity 9, variable cross-section reflection end 10, standing wave tube 11, variable cross-section confined space of bottom reflection end 13 common compositions.
In standing wave tube 11, bottom reflection end 13 upper fixed have loud speaker 12.Loud speaker 12 connects power amplifier 14 through lead-out wire, and power amplifier 14 also connects signal source 3, and signal source 3 connects computer 5 again.Wherein, computer 5 control signal sources 3 connection power amplifiers 14 drive loud speakers 12 and send the normal acoustic signals; The normal acoustic signals that loud speaker 12 sends repeatedly reflects to form the high sound pressure stationary field in above-mentioned variable cross-section confined space, sound pressure level can reach 94～160dB (for example: 94dB, 140dB, 150dB or 160dB), the sound wave distortion factor＜1% in the stationary field
The symmetric position place opens mouth in the two side of equiphase coupling cavity 9, is installed in passage port respectively with reference to microphone 8 and proofing microphone 3.Also be connected signal amplifier 15 through lead-out wire respectively with reference to microphone 8 with proofing microphone 3, signal amplifier 15 connects computer 5 again.Wherein, With reference to the sound pressure amplitude in the microphone 8 monitoring equiphase coupling cavitys 9; Through signal amplifier 15 real-time sound pressure amplitude is passed to computer 5, by the sound pressure amplitude in computer 5 control signal sources 3 and then the control equiphase coupling cavity 9, form feedback control loop again.
In equiphase coupling cavity 9, have the characteristic that microphone symmetric position phase place equates, can obtain microphone high sound pressure-phase-shift characterisitc with the phase difference of proofing microphone 3 under different sound pressure levels through witness mark microphone 8.
Adopt the detection method of the checkout gear of above-mentioned microphone high sound pressure-phase-shift characterisitc, it comprises the steps:
(a) by the sinusoidal signal of computer 5 control signal sources 3 output setpoint frequency f, sound pressure amplitude P0, the loud speaker 12 that drives in the standing wave tube 11 through power amplifier 14 then sends acoustic signals; Setpoint frequency f is that 500～800Hz (for example: 500Hz, 600Hz, 700Hz or 800Hz), sound pressure amplitude P0 are 1～2000Pa (for example: 1Pa, 100Pa, 1000Pa or 2000Pa).
(b) loud speaker 12 in the step (a) sends acoustic signals repeatedly reflection in the variable cross-section confined space; Form the stable state stationary field; Sound pressure amplitude and the phase place experienced with reference to microphone 8 and proofing microphone 1 are all equated; And sound pressure level reaches 94～160dB (for example: 94dB, 140dB, 150dB or 160dB), the distortion factor＜1%;
(c) collect the sound pressure amplitude P0 in the equiphase coupling cavity 9 with reference to microphone 8; Convert real-time sound pressure signal into electrical signal transfer through signal amplifier 15 and give computer 5; These data of computer 5 real-time analysiss; And the output amplitude of adjustment signal source 3, make the stable set point P0 that remains on of sound pressure amplitude in the equiphase coupling cavity 9, form close loop control circuit;
(d) will carry out the cross-spectrum analysis with reference to the signal that microphone 8 and proofing microphone 1 collect obtains: the phase difference of proofing microphone 1 relative reference microphone 8 under frequency f, sound pressure amplitude P0 condition promptly obtains microphone high sound pressure-phase-shift characterisitc.
Claims (3)
1. the checkout gear of a microphone high sound pressure-phase-shift characterisitc is characterized in that: this device comprises an equiphase coupling cavity (9) that falls " U " shape, and equiphase coupling cavity (9) center of being fixedly connected on has variable cross-section reflection end cap (10) top of through hole; The internal diameter of equiphase coupling cavity (9) equates that with the through hole internal diameter of variable cross-section reflection end cap (10) external diameter of equiphase coupling cavity (9) reflects the external diameter of end cap (10) less than variable cross-section; The top of standing wave tube (11) is fixedly connected on variable cross-section reflection end cap (10) below, and the bottom of standing wave tube (11) is fixedly connected on the bottom reflection end cap (13); The internal diameter of standing wave tube (11) reflects the through hole internal diameter of end cap (10) greater than variable cross-section, and the external diameter of standing wave tube (11) equals the external diameter of variable cross-section reflection end cap (10); Form a variable cross-section confined space through equiphase coupling cavity (9), variable cross-section reflection end cap (10), standing wave tube (11), bottom reflection end cap (13);
In standing wave tube (11), bottom reflection end cap (13) top is provided with loud speaker (12); Loud speaker (12) connects power amplifier (14) through lead-out wire, and power amplifier (14) also connects signal source (3), and signal source (3) connects computer (5) again; Wherein, computer (5) control signal source (3) connection power amplifier (14) drives loud speaker (12) and sends the normal acoustic signals; The normal acoustic signals that loud speaker (12) sends repeatedly reflects to form the high sound pressure stationary field in above-mentioned variable cross-section confined space;
Symmetric position place, two side at equiphase coupling cavity (9) opens mouth, is installed in passage port respectively with reference to microphone (8) and proofing microphone (3); Also be connected signal amplifier (15) through lead-out wire respectively with reference to microphone (8) with proofing microphone (3), signal amplifier (15) connects computer (5) again; Wherein, With reference to the sound pressure amplitude in microphone (8) the monitoring equiphase coupling cavity (9); Through signal amplifier (15) real-time sound pressure amplitude is passed to computer (5), again by the sound pressure amplitude in computer (5) control signal source (3) and then the control equiphase coupling cavity (9); Can obtain microphone high sound pressure-phase-shift characterisitc through witness mark microphone (8) with the phase difference of proofing microphone (3) under different sound pressure levels.
2. the checkout gear of a kind of microphone high sound pressure-phase-shift characterisitc according to claim 1 is characterized in that: the external diameter of described equiphase coupling cavity (9) is 1/2～1/3 times of external diameter of variable cross-section reflection end cap (10); The internal diameter of described standing wave tube (11) is 2～3 times of through hole internal diameter of variable cross-section reflection end cap (10).
3. the checkout gear of a kind of microphone high sound pressure-phase-shift characterisitc according to claim 1 and 2; It is characterized in that: the normal acoustic signals that described loud speaker (12) sends repeatedly reflects to form the high sound pressure stationary field in the variable cross-section confined space; Sound pressure level can reach 94～160dB, the sound wave distortion factor＜1% in this stationary field.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220063970 CN202488715U (en) | 2012-02-23 | 2012-02-23 | Detector of microphone high sound pressure-phase-shift characteristics |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220063970 CN202488715U (en) | 2012-02-23 | 2012-02-23 | Detector of microphone high sound pressure-phase-shift characteristics |
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| CN202488715U true CN202488715U (en) | 2012-10-10 |
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| CN 201220063970 Withdrawn - After Issue CN202488715U (en) | 2012-02-23 | 2012-02-23 | Detector of microphone high sound pressure-phase-shift characteristics |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102655628A (en) * | 2012-02-23 | 2012-09-05 | 北京航天计量测试技术研究所 | Device and method for detecting high sound pressure-phase shifting characteristic of microphone |
-
2012
- 2012-02-23 CN CN 201220063970 patent/CN202488715U/en not_active Withdrawn - After Issue
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102655628A (en) * | 2012-02-23 | 2012-09-05 | 北京航天计量测试技术研究所 | Device and method for detecting high sound pressure-phase shifting characteristic of microphone |
| CN102655628B (en) * | 2012-02-23 | 2014-07-23 | 北京航天计量测试技术研究所 | Device and method for detecting high sound pressure-phase shifting characteristic of microphone |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| AV01 | Patent right actively abandoned |
Granted publication date: 20121010 Effective date of abandoning: 20140723 |
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| RGAV | Abandon patent right to avoid regrant |