CN110677798A - Microphone with self-calibration function, calibration method thereof, sound transmission system and sound detection system - Google Patents

Abstract

The invention discloses a microphone with a self-calibration function, a calibration method thereof, a sound transmission system and a sound detection system. The microphone includes a microphone body and a self-calibration unit installed on the microphone body, and the self-calibration unit includes a second shell body and a self-calibration diaphragm installed on the casing, the self-calibration diaphragm and the sound transmission diaphragm of the microphone body are arranged in a gap to form a capacitor, and the second casing has a function for inputting AC excitation to the self-calibration diaphragm The excitation electrode input terminal of the voltage _; the sound transmission system and the sound detection system include the aforementioned microphones; the calibration method includes recording the effective value of the voltage U2 between the acoustic diaphragm and the back plate when the effective value _of the AC excitation power supply voltage is U1 as the microphone sensitivity. The invention does not require manual calibration of the microphone, is suitable for an acoustic online monitoring device, can greatly reduce the workload of noise detection personnel, improves the noise detection efficiency and accuracy, and has the advantages of convenient and quick calibration.

Description

Microphone with self-calibration function, calibration method, sound transmission system and sound detector measurement system

technical field

The invention relates to noise detection technology, in particular to a microphone with a self-calibration function, a calibration method thereof, a sound transmission system and a sound detection system.

Background technique

The microphone uses the sound-transmitting diaphragm to detect the air vibration caused by the sound wave, converts the sound wave signal into an electrical signal, and then calculates the noise value through the acquisition and weighting network. Since the temperature, humidity, and air pressure of the air may change at any time, which will affect the vibration response of the sound-transmitting diaphragm and change the sensitivity of the microphone, in order to ensure the accuracy of the noise measurement results, portable noise measurement equipment such as sound level meters and noise Prepolarized electret microphones used in online monitoring equipment require calibration during use. In the process of using the microphone, an acoustic calibrator is usually used to calibrate it, which has disadvantages such as manual operation, cumbersome process, low calibration efficiency, and increased noise detection workload. Especially for multi-channel online monitoring noise measurement devices, acoustic calibrators Calibration methods are basically impractical.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention: aiming at the above-mentioned problems of the prior art, a self-calibrating microphone and a calibration method thereof are provided that do not require manual calibration, have high calibration efficiency, and are convenient and quick. Self-calibration function of the microphone's sound transmission system and sound detection system.

In order to solve the above-mentioned technical problems, the technical scheme adopted in the present invention is:

First, the present invention provides a microphone with a self-calibration function, comprising a microphone body and a self-calibration unit mounted on the microphone body, the self-calibration unit comprising a second housing and a self-calibration membrane mounted on the housing The self-calibration diaphragm is arranged in a gap with the sound transmission diaphragm of the microphone body to form a capacitor, and the second housing has an excitation electrode input terminal for inputting an AC excitation voltage to the self-calibration diaphragm.

Optionally, the self-calibrating diaphragm is a porous metal plate with a stiffness greater than that of the sound-transmitting diaphragm.

Optionally, the self-calibrating diaphragm is fixed on the second casing by welding or sticking process and is kept insulated from the second casing.

Optionally, the second housing is screwed to the first housing of the microphone body.

Optionally, the microphone body is composed of a first shell, a sound-transmitting diaphragm and a back plate, the back plate and the sound-transmitting diaphragm constitute two substrates of a capacitor, and the sound-transmitting diaphragm is used for The air boost generated by the vibration sensing external sound source forms a current signal and outputs it through the output terminal on the first casing.

Optionally, a protective cover is further provided on the outer side of the self-calibrating diaphragm on the second housing, and the protective cover is provided with an opening for conducting sound.

Optionally, the protective cover and the second housing are screwed together.

In addition, the present invention also provides a sound transmission system with a self-calibration function, comprising an AC excitation voltage source and the microphone with a self-calibration function, an output end of the AC excitation voltage source and an excitation electrode input of the microphone terminals are connected.

In addition, the present invention also provides a sound detection system, comprising an AC excitation voltage source, the microphone with the self-calibration function, a central processing unit, an output end of the AC excitation voltage source and an excitation electrode input terminal of the microphone The control end of the AC excitation voltage source is connected to the output end of the central processing unit, and the output end of the microphone is connected to the input end of the central processing unit.

In addition, the present invention also provides a method for calibrating the aforementioned microphone with a self-calibration function, and the implementation steps include:

1) Input the AC excitation voltage to the self-calibrating diaphragm;

2) Record the effective value U ₂ of the voltage between the sound-transmitting diaphragm of the microphone body and its back plate when the effective value of the input AC excitation power supply voltage is U ₁ ;

3) Take the voltage effective value U ₂ as the sensitivity output of the microphone.

Compared with the prior art, the present invention has the following advantages: the microphone with self-calibration function of the present invention includes a microphone body and a self-calibration unit installed on the microphone body, and the self-calibration unit includes a second housing and is installed on the housing. The self-calibration diaphragm is arranged in the gap between the self-calibration diaphragm and the sound-transmitting diaphragm of the microphone body to form a capacitor, and the second housing has an excitation electrode input terminal for inputting an AC excitation voltage to the self-calibration diaphragm, wherein the self-calibration diaphragm is The calibration diaphragm is used to apply the AC excitation voltage from the AC excitation power supply, and it forms the two polar plates of the capacitor with the sound transmission diaphragm. Since the sound transmission diaphragm is grounded, the above voltage signal is used to make the self-calibration diaphragm and the sound transmission diaphragm. An alternating force is generated between the two, which causes the sound-transmitting diaphragm to produce the same deformation amount as that of the acoustic calibrator, which is equivalent to the acoustic calibration effect and achieves the purpose of calibrating the sensitivity of the microphone. The invention can use electrical signal calibration instead of acoustic signal calibration, integrate the calibrator and the microphone without changing the acoustic performance of the microphone, realize automatic calibration of the sensitivity of the microphone, without human intervention in the calibration process, reduce the workload of microphone calibration, and ensure noise measurement The accuracy of the results is especially suitable for multi-point, multi-channel, and maintenance-free online monitoring devices for noise signals.

The sound transmission system and sound detection system with self-calibration function of the present invention include the microphone with self-calibration function of the present invention, so it also has the aforementioned advantages of the microphone with self-calibration function of the present invention, so it is not repeated here.

Description of drawings

FIG. 1 is an external structural diagram of a microphone with a self-calibration function according to an embodiment of the present invention.

FIG. 2 is an internal structural diagram of a microphone with a self-calibration function according to an embodiment of the present invention.

FIG. 3 is a schematic diagram of a microphone calibration method with a self-calibration function according to an embodiment of the present invention.

Detailed ways

As shown in FIG. 1 and FIG. 2 , the microphone with self-calibration function in this embodiment includes a microphone body 1 and a self-calibration unit 2 mounted on the microphone body 1. The self-calibration unit 2 includes a second housing 21 and a self-calibration unit 2 mounted on the housing. The self-calibration diaphragm 22 on the 21, the self-calibration diaphragm 22 and the sound transmission diaphragm 11 of the microphone body 1 are arranged in a gap to form a capacitor, and the second housing 21 has an excitation for inputting the AC excitation voltage to the self-calibration diaphragm 22. Electrode input terminal. Among them, the self-calibration diaphragm 22 is used to apply the AC excitation voltage from the AC excitation power supply, and the two polar plates of the capacitor are formed with the acoustic diaphragm 11. Since the acoustic diaphragm 11 is grounded, the above-mentioned voltage signal is used to make the self-calibration diaphragm There is an alternating force between 22 and the sound-transmitting diaphragm 11, which causes the sound-transmitting diaphragm 11 to generate the same deformation amount as that of the acoustic calibrator, which is equivalent to the acoustic calibration effect and achieves the sensitivity of the calibrated microphone. the goal of.

In this embodiment, the self-calibration diaphragm 22 is a porous metal plate with a rigidity greater than that of the sound-transmitting diaphragm 11 . The rigidity of the porous metal plate is much greater than that of the sound-transmitting diaphragm 11, and it will not be deformed by air vibration. The size and number of the diaphragm openings on the self-calibrating diaphragm 22 are required to produce almost no measurement results for noise signals in the audible sound frequency range. influences.

In this embodiment, the self-calibration diaphragm 22 is fixed on the second casing 21 by welding or sticking process, and is kept insulated from the second casing 21, which is convenient for processing and production.

In this embodiment, the second casing 21 is screwed to the first casing 12 of the microphone body 1 , which is convenient and quick to assemble.

As shown in FIGS. 1 and 2 , in this embodiment, the microphone body 1 is composed of a first casing 12 , a sound-transmitting diaphragm 11 and a back plate 13 , and the back plate 13 and the sound-transmitting diaphragm 11 constitute two capacitors. The substrate, the sound-transmitting diaphragm 11 is used to sense the air boost generated by the external sound source based on the vibration to form a current signal and output it through the output terminal on the first housing 12 . The acoustic diaphragm 11 is used to sense the air sound pressure generated by the external sound source; the back plate 13 is used to inject permanent electric charges, and forms two polar plates of the capacitor with the acoustic diaphragm 11 . The first housing 12 is used to support the sound-transmitting diaphragm 11 . Undoubtedly, the present embodiment can also adopt other structures of microphones as required, regardless of its internal structure, as long as it has a separate sound-transmitting diaphragm 11 , it can be applied to the self-calibration unit 2 .

As shown in FIG. 1 and FIG. 2 , the second casing 21 is further provided with a protective cover 3 on the outer side of the self-calibration diaphragm 22 , and the protective cover 3 is provided with an opening 31 for conducting sound. In this embodiment, the protective cover 3 is a metal cover, which is used to protect the self-calibration diaphragm 22 from external damage. The openings 31 are used to allow sound waves to be received by the sound-transmitting diaphragm 11 through the protective cover 3 without affecting the acoustic performance of the microphone. Wherein, the size and quantity of the openings 31 have little influence on the measurement result of the noise signal in the audible sound frequency range.

In this embodiment, the protective cover 3 and the second housing 21 are connected by screw threads, which is convenient and quick to assemble.

In addition, this embodiment also provides a sound transmission system with a self-calibration function, including an AC excitation voltage source and the aforementioned microphone with a self-calibration function in this embodiment, an output end of the AC excitation voltage source and an excitation electrode input terminal of the microphone connected. The AC excitation power supply is used to generate a fixed frequency alternating voltage effective value U ₁ , and the distributed electromotive force generated by the alternating voltage effective value U ₁ to the sound-transmitting diaphragm 11 is used to simulate the effect of external changing sound pressure on the sound-transmitting diaphragm 11 , the effective value U2 of the voltage between the acoustic diaphragm 11 and the back plate 13 caused by the alternating voltage effective value U ₁ and the voltage between the acoustic diaphragm ₁₁ and the back plate 13 caused by the acoustic calibrator The value is the same, and the automatic calibration of the microphone is completed according to this principle.

In addition, this embodiment also provides a sound detection system, which includes an AC excitation voltage source, a microphone with a self-calibration function described in this embodiment, and a central processing unit. The output end of the AC excitation voltage source is connected to the excitation electrode input terminal of the microphone. , the control end of the AC excitation voltage source is connected with the output end of the central processing unit, and the output end of the microphone is connected with the input end of the central processing unit. The sound detection system is a typical application of the microphone with the self-calibration function mentioned in this embodiment, and the central processing unit may be the central processing unit of a sound level meter or an online monitoring device, and the sound level meter or the online monitoring device may be used. The central processing unit controls the operation of the AC excitation power supply and sets the calibration period.

In addition, as shown in FIG. 3 , this embodiment also provides a method for calibrating the aforementioned microphone with a self-calibration function, and the implementation steps include:

1) Input the AC excitation voltage to the self-calibration diaphragm 22;

2) Record the effective value U ₂ of the voltage between the sound-transmitting diaphragm 11 of the microphone body 1 and its back plate 13 when the effective value of the input AC excitation power supply voltage is U ₁ ;

3) Take the voltage effective value U ₂ as the sensitivity output of the microphone.

The above are only the preferred embodiments of the present invention, and the protection scope of the present invention is not limited to the above-mentioned embodiments, and all technical solutions under the idea of the present invention belong to the protection scope of the present invention. It should be pointed out that for those skilled in the art, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims (10)

1. Microphone with self-calibration function, comprising a microphone body (1), characterized in that: the microphone further comprises a self-calibration unit (2) mounted on the microphone body (1), the self-calibration unit (2) comprises a second housing (21) and a self-calibration diaphragm (22) mounted on the housing (21), the self-calibration diaphragm (22) and the microphone diaphragm (11) of the microphone body (1) are arranged in a clearance mode to form a capacitor, and the second housing (21) is provided with an excitation electrode input terminal used for inputting an alternating current excitation voltage to the self-calibration diaphragm (22).

2. Microphone with self-calibration function according to claim 1, characterized by the fact that: the self-calibration diaphragm (22) is a porous metal plate with rigidity greater than that of the acoustic diaphragm (11).

3. Microphone with self-calibration function according to claim 1, characterized by the fact that: the self-aligning membrane (22) is fixed on the second shell (21) through a welding or pasting process and is insulated from the second shell (21).

4. Microphone with self-calibration function according to claim 1, characterized by the fact that: the second shell (21) is in threaded connection with the first shell (12) of the microphone body (1).

5. Microphone with self-calibration function according to claim 4, characterized by the fact that: microphone body (1) comprises first casing (12), sound transmission diaphragm (11) and back plate (13), two base plates of electric capacity are constituteed to back plate (13) and sound transmission diaphragm (11), sound transmission diaphragm (11) are used for based on the air that vibration perception external sound source produced steps up and form current signal and export through the output terminal on first casing (12).

6. The microphone with the self-calibration function according to any one of claims 1 to 5, wherein: and a protective cover (3) is arranged on the second shell (21) and positioned on the outer side of the self-calibration membrane (22), and an opening (31) for conducting sound is formed in the protective cover (3).

7. Microphone with self-calibration function according to claim 6, characterized by the fact that: the protective cover (3) is in threaded connection with the second shell (21).

8. An acoustic system with self-calibration function, comprising an ac excitation voltage source and a microphone with self-calibration function according to any one of claims 1 to 7, wherein an output terminal of the ac excitation voltage source is connected to an excitation electrode input terminal of the microphone.

9. A sound detection system, characterized in that, it includes AC excitation voltage source, the microphone with self-calibration function of any claim 1-7, and central processing unit, the output terminal of the AC excitation voltage source is connected with the excitation electrode input terminal of the microphone, the control terminal of the AC excitation voltage source is connected with the output terminal of the central processing unit, the output terminal of the microphone is connected with the input terminal of the central processing unit.

10. A calibration method for a microphone with a self-calibration function according to any one of claims 1 to 7, characterized by comprising the steps of:

1) inputting an alternating current excitation voltage to the self-calibration diaphragm (22);

2) recording the effective value of the voltage of the input AC excitation power supplyU ₁Effective value of voltage between the sound transmission diaphragm (11) of the microphone body (1) and the back plate (13) thereofU ₂；

3) Effective value of voltageU ₂As the sensitivity output of the microphone.

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