阅读说明：本技术 具有自校准功能的传声器及其校准方法、传声系统和声音检测系统 (Microphone with self-calibration function, calibration method thereof, sound transmission system and sound detection system ) 是由 吴晓文 卢铃 曹浩 彭继文 吕建红 于 2019-09-09 设计创作，主要内容包括：本发明公开了一种具有自校准功能的传声器及其校准方法、传声系统和声音检测系统,传声器包括传声器本体及包括安装在传声器本体上的自校准单元,所述自校准单元包括第二壳体和安装在壳体上的自校准膜片,所述自校准膜片与传声器本体的传声膜片间隙布置构成电容,所述第二壳体上具有用于向自校准膜片输入交流激励电压的激励电极输入端子；传声系统和声音检测系统包括前述传声器；校准方法包括记录交流激励电源电压有效值为<I>U</I><Sub>1</Sub>时传声膜片与背极板之间的电压有效值<I>U</I><Sub>2</Sub>作为传声器灵敏度。本发明无需人为校准传声器,适用于声学在线监测装置,可大幅降低噪声检测人员的工作量,提高了噪声检测效率与精度,具有校准方便快捷的优点。(The invention discloses a microphone with a self-calibration function, a calibration method thereof, a sound transmission system and a sound detection system, wherein the microphone comprises a microphone body and a self-calibration unit arranged on the microphone body, the self-calibration unit comprises a second shell and a self-calibration diaphragm arranged on the shell, the self-calibration diaphragm and the sound transmission diaphragm of the microphone body are arranged in a gap manner to form a capacitor, and the second shell is provided with an excitation electrode input terminal used for inputting alternating-current excitation voltage to the self-calibration diaphragm; the sound transmission system and the sound detection system comprise the microphone; the calibration method comprises recording the effective value of AC excitation power supply voltage as U 1 Effective value of voltage between time-acoustic diaphragm and back plate U 2 As microphone sensitivity. The invention does not need to manually calibrate the microphone, is suitable for the acoustic online monitoring device, can greatly reduce the workload of noise detection personnel, improves the noise detection efficiency and precision, and has the advantage of convenient and rapid calibration.)

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.

Technical Field

The invention relates to a 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

The microphone detects air vibration caused by sound waves by using a sound transmission diaphragm, converts sound wave signals into electric signals, and calculates a noise value through acquisition, a weighting network and the like. Since the temperature, humidity, air pressure and the like of air may change at any time, thereby affecting the vibration response of the microphone and changing the sensitivity of the microphone, in order to ensure the accuracy of the noise measurement result, calibration is required during the use of portable noise measurement equipment such as a sound level meter and the like and a pre-polarized electret microphone used by noise on-line monitoring equipment. The microphone is usually calibrated by using an acoustic calibrator in the using process, the defects of manual operation, complex process, low calibration efficiency, increased noise detection workload and the like exist, and particularly for a multi-channel online monitoring noise measuring device, the calibration method of the acoustic calibrator basically has no practical feasibility.

Disclosure of Invention

The technical problems to be solved by the invention are as follows: aiming at the problems in the prior art, the invention provides a microphone with a self-calibration function, which is free from artificial calibration, high in calibration efficiency, convenient and quick, and a calibration method thereof.

In order to solve the technical problems, the invention adopts the technical scheme that:

the invention provides a microphone with a self-calibration function, which comprises a microphone body and a self-calibration unit arranged on the microphone body, wherein the self-calibration unit comprises a second shell and a self-calibration diaphragm arranged on the shell, the self-calibration diaphragm and a microphone diaphragm of the microphone body are arranged in a clearance mode to form a capacitor, and an excitation electrode input terminal used for inputting an alternating-current excitation voltage to the self-calibration diaphragm is arranged on the second shell.

Optionally, the self-calibrating diaphragm is a perforated metal plate having a stiffness greater than the acoustic diaphragm.

Optionally, the self-aligning diaphragm is fixed to the second housing by a welding or gluing process and is insulated from the second housing.

Optionally, the second housing is threadedly connected with the first housing of the microphone body.

Optionally, the microphone body comprises first casing, sound transmission diaphragm and back plate, back plate and sound transmission diaphragm constitute two base plates of electric capacity, the sound transmission diaphragm is used for based on the air that vibration perception external sound source produced steps up and forms current signal and export through the output terminal on the first casing.

Optionally, a protective cover is further disposed on the second housing outside the self-calibration diaphragm, and the protective cover is provided with an opening for transmitting sound.

Optionally, a threaded connection between the protective cover and the second housing.

In addition, the invention also provides a sound transmission system with a self-calibration function, which comprises an alternating current excitation voltage source and the microphone with the self-calibration function, wherein the output end of the alternating current excitation voltage source is connected with the excitation electrode input terminal of the microphone.

In addition, the invention also provides a sound detection system, which comprises an alternating current excitation voltage source, the microphone with the self-calibration function and a central processing unit, wherein the output end of the alternating current excitation voltage source is connected with the excitation electrode input terminal of the microphone, the control end of the alternating current 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.

In addition, the present invention further provides a calibration method for a microphone with a self-calibration function, which includes the following implementation steps:

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

2) recording the effective value of the voltage of the input AC excitation power supplyU ₁Effective voltage value between microphone diaphragm and back plate of microphoneU ₂；

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

Compared with the prior art, the invention has the following advantages: the microphone with the self-calibration function comprises a microphone body and a self-calibration unit arranged on the microphone body, wherein the self-calibration unit comprises a second shell and a self-calibration diaphragm arranged on the shell, the self-calibration diaphragm and a sound transmission diaphragm of the microphone body are arranged in a clearance way to form a capacitor, the second housing has an excitation electrode input terminal thereon for inputting an alternating excitation voltage to the self-calibrating diaphragm, wherein the self-calibration diaphragm is used for applying an alternating current excitation voltage from an alternating current excitation power supply and forms two polar plates of a capacitor with the acoustic diaphragm, because the acoustic diaphragm is grounded, the voltage signal is utilized to generate alternating acting force between the self-calibration diaphragm and the acoustic diaphragm, the acting force enables the sound transmission diaphragm to generate the deformation amount which is the same as that of the sound calibrator during calibration, so that the aim of calibrating the sensitivity of the microphone is fulfilled with the equivalent sound calibration effect. The invention can utilize the electric signal calibration to replace the acoustic signal calibration, integrates the calibrator and the microphone without changing the acoustic performance of the microphone, can realize the automatic calibration of the sensitivity of the microphone, does not need human intervention in the calibration process, reduces the calibration workload of the microphone, ensures the accuracy of the noise measurement result, and is particularly suitable for a multi-measuring-point, multi-channel and maintenance-free noise signal online monitoring device.

The sound transmission system and the sound detection system with the self-calibration function of the present invention include the microphone with the self-calibration function of the present invention, and therefore, the foregoing advantages of the microphone with the self-calibration function of the present invention are also provided, and thus, the details are not described herein again.

Drawings

Fig. 1 is an external structural view of a microphone having a self-calibration function according to an embodiment of the present invention.

Fig. 2 is an internal structural view of a microphone having 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 Description

As shown in fig. 1 and 2, the microphone with the self-calibration function of the present 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 case 21 and a self-calibration diaphragm 22 mounted on the case 21, the self-calibration diaphragm 22 is arranged in a gap with the acoustic diaphragm 11 of the microphone body 1 to form a capacitance, and the second case 21 has an excitation electrode input terminal for inputting an ac excitation voltage to the self-calibration diaphragm 22. The self-calibration diaphragm 22 is used for applying an alternating-current excitation voltage from an alternating-current excitation power supply, and forms two polar plates of a capacitor with the sound transmission diaphragm 11, because the sound transmission diaphragm 11 is grounded, the voltage signal is utilized to generate an alternating acting force between the self-calibration diaphragm 22 and the sound transmission diaphragm 11, and the acting force enables the sound transmission diaphragm 11 to generate the deformation quantity which is the same as that generated by the calibration of an acoustic calibrator, so that the aim of calibrating the sensitivity of the microphone is achieved.

In this embodiment, the self-aligning diaphragm 22 is a perforated metal plate having a rigidity greater than that of the acoustic diaphragm 11. The rigidity of the porous metal plate is far greater than that of the acoustic diaphragm 11, deformation does not occur due to air vibration, and the requirement on the size and the number of the diaphragm openings on the self-calibration diaphragm 22 hardly influences the measurement result of a noise signal in an audible frequency range.

In this embodiment, the self-calibration diaphragm 22 is fixed on the second housing 21 by a welding or pasting process and is insulated from the second housing 21, which facilitates the manufacturing process.

In this embodiment, the second housing 21 is screwed to the first housing 12 of the microphone body 1, so that the assembly is convenient and fast.

As shown in fig. 1 and 2, in the present embodiment, the microphone body 1 is composed of a first case 12, a sound transmission diaphragm 11 and a back plate 13, the back plate 13 and the sound transmission diaphragm 11 constitute two substrates of a capacitor, and the sound transmission diaphragm 11 is configured to sense an air pressure rise generated by an external sound source based on vibration to form a current signal and output the current signal through an output terminal on the first case 12. The acoustic diaphragm 11 is used for sensing air sound pressure generated by an external sound source; the back plate 13 is used for injecting permanent charges and forms two plates of a capacitor with the acoustic diaphragm 11. The first housing 12 is used to support the acoustic diaphragm 11. It goes without saying that the present embodiment can also adopt microphones of other structures as required, regardless of their internal structure, as long as they present a separate acoustic diaphragm 11, which can be adapted to the self-calibration unit 2.

As shown in fig. 1 and 2, a protective cover 3 is further provided on the second housing 21 outside the self-alignment diaphragm 22, and an opening 31 for transmitting sound is opened in the protective cover 3. In this embodiment, the protective cover 3 is a metal cover for protecting the self-calibration diaphragm 22 from external damage. The opening 31 serves 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. The size and number of the openings 31 are such that they have little effect on the measurement of noise signals in the audible frequency range.

In this embodiment, the protective cover 3 and the second housing 21 are connected by screw threads, and the assembly is convenient and fast.

In addition, the present embodiment further provides a sound transmission system with a self-calibration function, which includes an ac excitation voltage source and the microphone with the self-calibration function described above, where an output terminal of the ac excitation voltage source is connected to an excitation electrode input terminal of the microphone. AC excitation power supply for generating effective value of alternating voltage with fixed frequencyU ₁Using the effective value of the alternating voltageU ₁The distributed electromotive force generated by the acoustic diaphragm 11 simulates the action of the externally changed sound pressure on the acoustic diaphragm 11, and the effective value of the alternating voltageU ₁Resulting in an effective value of the voltage between the acoustic diaphragm 11 and the back plate 13U ₂The automatic calibration of the microphone is done according to this principle, as is the voltage value between the acoustic diaphragm 11 and the backplate 13 caused by the acoustic calibrator.

In addition, the present embodiment further provides a sound detection system, which includes an ac excitation voltage source, the microphone with the self-calibration function of the present embodiment, and a central processing unit, wherein an output terminal of the ac excitation voltage source is connected to an excitation electrode input terminal of the microphone, a control terminal of the ac excitation voltage source is connected to an output terminal of the central processing unit, and an output terminal of the microphone is connected to an input terminal of the central processing unit. The sound detection system is a typical application of the microphone with the self-calibration function in the embodiment, and the central processing unit may be a sound level meter or a central processing unit of an online monitoring device, and the sound level meter or the central processing unit of the online monitoring device may be used to control the operation mode of the ac excitation power supply, and set the calibration period.

In addition, as shown in fig. 3, the present embodiment further provides a calibration method for a microphone with a self-calibration function, which includes:

1) inputting an alternating 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.

The above description is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments, and all technical solutions belonging to the idea of the present invention belong to the protection scope of the present invention. It should be noted that modifications and embellishments within the scope of the invention may occur to those skilled in the art without departing from the principle of the invention, and are considered to be within the scope of the invention.