Capacitive anti-vibration infrasound sensor and signal processing method

Abstract

The invention discloses a capacitive anti-vibration infrasound sensor, which is characterized by comprising an X-direction pole head pair, a Y-direction pole head pair, a Z-direction pole head pair and a processing circuit, the X-direction pole head pair, the Y-direction pole head pair and the Z-direction pole head pair are arranged in three orthogonal directions of the capacitive vibration infrasonic sensor and are used for sensing infrasonic waves and vibration signals in the X direction, the Y direction and the Z direction, the X-direction pole head pair, the Y-direction pole head pair and the Z-direction pole head pair are respectively provided with three groups of symmetrical vibrating diaphragms; and the processing circuit comprises six paths of inputs and is used for converting capacitance signals of each path into voltage change after impedance conversion and carrying out vibration noise offset processing and infrasound pressure calculation by utilizing an adder carried in the processing circuit. By applying the sensor, the vibration component can be counteracted through an algorithm, so that the acceleration sensitivity of the sensor is reduced, and the anti-vibration capability is improved.

Description

Technical Field

[0001] The present application relates to the technical field of anti-vibration infrasound sensors, and in particular to a capacitive anti-vibration infrasound sensor and a signal processing method. Background Art

[0002] An infrasound sensor is a microphone that can receive infrasound wave signals in the air. Its lower frequency limit can reach 0.003 Hz. It can be used for infrasound detection of long-distance targets, monitoring of natural disasters such as earthquakes and mudslides, and infrasound noise measurement.

[0003] Existing infrasound sensor products can be divided into two categories according to their working principles: capacitive and dynamic.

[0004] For capacitive infrasound sensors, their acoustically sensitive structure is a variable capacitor composed of a circular fixed metal film (diaphragm) and a back plate. The diaphragm will undergo forced vibration under the action of infrasound waves, and the capacitance value will change accordingly, and then a voltage signal will be generated through an impedance conversion circuit.

[0005] For dynamic infrasound sensors, the main products are the French MB series, which has an operating frequency range of 0.01Hz-27Hz, a sensitivity of 20mV / Pa, and has online sensitivity detection and calibration functions. However, due to the transducer structure, dynamic infrasound sensors have a high acceleration sensitivity and are easily disturbed by vibration signals. They have a poor signal-to-noise ratio and are demanding on the use environment. Capacitive infrasound sensors have the advantages of high sensitivity, low background noise, flat frequency response curve, and vibration resistance. In recent years, they have gradually replaced dynamic products and have been widely used.

[0006] Although capacitive infrasound sensors have stronger vibration resistance than dynamic infrasound sensors, they still have a certain acceleration sensitivity (when the sound pressure sensitivity is 12.5mV / Pa, the acceleration sensitivity is 10mV / (ms-2)). Therefore, in a vibration environment (such as an engine test bench, a large wind tunnel, etc.), the noise caused by strong vibration (10grms) is numerically equal to a sound pressure signal of approximately 100Pa (134dB), resulting in a decrease in the test signal-to-noise ratio and affecting the sound pressure measurement range of the sensor.

[0007] In view of this, how to provide a capacitive vibration-resistant infrasound sensor to solve the problem of insufficient measurement range of existing capacitive infrasound sensors in vibration environments due to high acceleration sensitivity, thereby improving the sound pressure measurement capability of infrasound sensors in vibration environments, has become a technical problem that urgently needs to be solved. Summary of the invention

[0008] The embodiment of the present application provides a capacitive anti-vibration infrasound sensor, which is used to solve the problem of insufficient measurement range of current capacitive infrasound sensors in a vibration environment due to high acceleration sensitivity.

[0009] In a first aspect of an embodiment of the present application, there is provided a capacitive anti-vibration infrasound sensor, comprising: an X-direction pole head pair, a Y-direction pole head pair, a Z-direction pole head pair and a processing circuit;

[0010] The X-direction pole head pair, the Y-direction pole head pair, and the Z-direction pole head pair are arranged in three orthogonal directions of the capacitive vibration infrasound sensor, and are used to sense infrasound waves and vibration signals in the X-direction, Y-direction, and Z-direction directions, wherein three groups of symmetrical diaphragms are respectively arranged on the X-direction pole head pair, the Y-direction pole head pair, and the Z-direction pole head pair, and when the capacitive anti-vibration sensor is in a vibration environment, the displacement directions of the axisymmetric diaphragms caused by vibration are the same, and the displacement directions of the axisymmetric diaphragms caused by sound pressure are opposite;

[0011] The processing circuit includes six inputs, which are used to convert the capacitance signals of each channel into voltage changes after impedance transformation, and use the adder carried in the processing circuit to perform vibration noise cancellation processing and infrasound sound pressure calculation.

[0012] In a second aspect of the embodiments of the present application, a signal processing method using a capacitive anti-vibration infrasound sensor as described in the first aspect of the embodiments of the present application is provided, comprising:

[0013] When the vibration direction of the environment in which the capacitive anti-vibration infrasound sensor is located is upward, a first output signal value corresponding to a first pole head in the Z-direction pole head pair and a second output signal value corresponding to a second pole head are obtained, wherein, when the vibration direction is upward, a first diaphragm corresponding to the first pole head in the Z-direction pole head pair is convex, and a second diaphragm corresponding to the second pole head is concave;

[0014] Obtain a third output signal value corresponding to the first pole head in the X-direction pole head pair, and a fourth output signal value corresponding to the second pole head, wherein, when the vibration direction is upward, the upper half of the third diaphragm corresponding to the first pole head in the X-direction pole head pair is concave and the lower half is convex, and the upper half of the fourth diaphragm corresponding to the second pole head is convex and the lower half is concave;

[0015] Using an adder in a processing circuit, the first output signal value and the second output signal value are processed to cancel vibration noise and calculate sound pressure;

[0016] The third output signal value and the fourth output signal value are processed by an adder in the processing circuit to perform vibration noise cancellation and sound pressure calculation.

[0017] The present application provides a capacitive anti-vibration infrasound sensor, characterized in that it comprises: an X-direction pole head pair, a Y-direction pole head pair, a Z-direction pole head pair and a processing circuit; the X-direction pole head pair, the Y-direction pole head pair and the Z-direction pole head pair are arranged in three orthogonal directions of the capacitive vibration infrasound sensor, and are used to sense infrasound waves and vibration signals in the X-direction, Y-direction and Z-direction directions, wherein three groups of symmetrical diaphragms are respectively arranged on the X-direction pole head pair, the Y-direction pole head pair and the Z-direction pole head pair; the processing circuit comprises six inputs, which are used to convert the capacitance signals of each channel into voltage changes after impedance transformation, and use the adder carried in the processing circuit to perform vibration noise cancellation processing and infrasound sound pressure calculation.

[0018] The capacitive anti-vibration infrasound sensor provided by the embodiment of the present application adopts a regular hexahedron structure and designs three sets of symmetrical diaphragms in three orthogonal directions. When the sensor is in a vibrating environment, the displacement directions of the symmetrical diaphragms caused by the vibration are the same, and the displacement directions of the symmetrical diaphragms caused by the sound pressure are opposite, so the vibration component can be offset by an algorithm, thereby reducing the acceleration sensitivity of the sensor and improving the anti-vibration capability.

[0019] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, which can be implemented in accordance with the contents of the specification, and in order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present application. Also, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0021] Figure 1 A schematic diagram of the structure of a capacitive infrasound sensor provided in an embodiment of the present application;

[0022] Figure 2 A schematic diagram of the structure of a capacitive infrasound sensor provided in an embodiment of the present application that vibrates upward from a stationary state;

[0023] Figure 3 A schematic diagram of the structure of an anti-vibration infrasound sensor provided in an embodiment of the present application vibrating downward from the highest point;

[0024] Figure 4 A schematic diagram of the appearance structure of a capacitive anti-vibration infrasound sensor provided in an embodiment of the present application;

[0025] Figure 5 A schematic flow chart of a signal processing method using a capacitive anti-vibration infrasound sensor provided in an embodiment of the present application;

[0026] Figure 6 A schematic diagram of the structure of a capacitive anti-vibration infrasound sensor provided in an embodiment of the present application, wherein the vibration direction is upward;

[0027] Figure 7 A schematic flow chart of another signal processing method using a capacitive anti-vibration infrasound sensor provided in an embodiment of the present application;

[0028] Figure 8 A schematic diagram of the structure of a capacitive anti-vibration infrasound sensor without vibration and with increased sound pressure provided in an embodiment of the present application;

[0029] Among them, 1-front cavity, 2-support ring, 3-diaphragm, 4-back plate, 5-pressure equalizing hole, 6-back cavity, 7-frame, 8-support point, (9-1, 9-2)-X direction pole head pair, (11-1, 11-2)-Z direction pole head pair. DETAILED DESCRIPTION

[0030] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0031] Capacitive infrasound sensor such as Figure 1 As shown, it is mainly composed of a front cavity (1), a support ring (2), a diaphragm (3), a back plate (4), a pressure equalizing hole (5) and a rear cavity (6). The diaphragm (3) and the back plate (4) form a head capacitor. When a sound wave acts on the diaphragm (3), the diaphragm (3) will vibrate under pressure, causing the capacitance value to change. The sound wave is characterized by detecting the change in the capacitance value, thereby realizing the conversion of sound wave to electrical signal. In order to ensure that the diaphragm (3) is flat, the diaphragm (3) needs to be tightly stretched on the support ring (2) with a certain tension.

[0032] The frequency response lower limit of the infrasound sensor can reach 0.003 Hz. In order to achieve such a low frequency detection lower limit, the infrasound sensor has a nearly sealed back cavity (6). The back cavity (6) is made of rigid material (metal, organic plastic, etc.). When the sensor is in a vibrating environment, the back cavity will vibrate at the same frequency as the environment. However, due to the inertia of the gas in the cavity, the average displacement ΔL of the gas along the vibration direction will lag behind the displacement ΔS of the back cavity as a whole, which will cause the gas density on both sides of the diaphragm to change, thereby causing local air pressure changes and the diaphragm position to shift, which is equivalent to the change in the diaphragm position caused by the sound pressure effect, thereby introducing acceleration noise and affecting the measurement range.

[0033] The effect of vibration environment noise on infrasound sensors is specifically deduced as follows:

[0034] Since the pressure equalizing hole (5) is small enough, when the rear cavity (6) produces a small displacement under a vibration environment, the change in the gas molar amount of the rear cavity (6) caused by the gas flow through the pressure equalizing hole (5) in a short period of time is very small, and the overall density change of the gas in the rear cavity (6) can be ignored. At this time, depending on the vibration direction, the displacement change trend of the diaphragm (3) of the infrasound sensor is as follows:

[0035] (1) When the sensor starts to vibrate upward from a stationary state, the entire back cavity (6) of the infrasound sensor will produce a small upward displacement ΔS, and the average displacement of the gas in the cavity is ΔL. Since the displacement of the gas in the cavity lags behind the displacement of the shell in time, when the vibration just starts, ΔS>ΔL. At this time, the density of the gas in the cavity gradually decreases with the increase of height. Considering that the overall density of the gas in the cavity is consistent with the outside world, the gas density at the diaphragm (3) is relatively low at this time, which is less than the external air pressure, causing the diaphragm (3) to sag (such as Figure 2 As shown), it is equivalent to an increase in external sound pressure.

[0036] (2) When the sensor starts to vibrate downward from the highest point of vibration, the displacement ΔS of the rear cavity (6) is still greater than the average displacement of the gas, which is ΔL. Since the displacement of the gas in the cavity lags behind the displacement of the shell, as ΔS gradually decreases, ΔL first increases and then decreases. At this time, the density of the gas in the cavity gradually increases with the increase in height, and is highest at the diaphragm, which is greater than the external air pressure. This will cause the diaphragm (3) to bulge upward (such as Figure 3 ), which is equivalent to a reduction in external sound pressure.

[0037] (3) When the sensor starts to vibrate upward from the lowest point, the change trend of the diaphragm is opposite to that of process (2), which is equivalent to an increase in external air pressure.

[0038] Therefore, as the sensor vibrates, the diaphragm also vibrates periodically due to the change in gas density in the cavity, thereby introducing vibration noise. Therefore, in order to improve the vibration resistance of the infrasound sensor, the key is to reduce the acceleration sensitivity of the sensor and reduce the change in equivalent sound pressure caused by vibration.

[0039] The present invention designs an anti-vibration infrasound sensor, which adopts a regular hexahedron structure and designs three sets of symmetrical diaphragms in three orthogonal directions. When the sensor is in a vibrating environment, the displacement directions of the symmetrical diaphragms caused by the vibration are the same, and the displacement directions of the symmetrical diaphragms caused by the sound pressure are opposite, so the vibration component can be offset by an algorithm, thereby reducing the acceleration sensitivity of the sensor and improving the anti-vibration ability.

[0040] See also Figure 4 , Figure 4 A schematic diagram of the appearance and structure of a capacitive anti-vibration infrasound sensor provided in an embodiment of the present application.

[0041] like Figure 4 As shown, the capacitive anti-vibration infrasound sensor provided in the embodiment of the present application adopts a regular hexahedron structure, involves three groups of symmetrical pole heads in three orthogonal directions, and senses vibration signals in three directions. It is mainly composed of a frame (7), a support point (8), an X-direction pole head pair (9-1, 9-2), a Y-direction pole head pair, a Z-direction pole head pair (11-1, 11-2) and a back cavity (6). In addition, the capacitive anti-vibration infrasound sensor also includes: a bracket, an inner cavity, a back plate (4), a pressure equalizing hole (5), and a processing circuit.

[0042] Specifically, the X-direction pole head pair, the Y-direction pole head pair, and the Z-direction pole head pair are arranged in three orthogonal directions of the capacitive vibration infrasound sensor, and are used to sense infrasound waves and vibration signals in the X-direction, Y-direction, and Z-direction. Three groups of symmetrical diaphragms are respectively arranged on the X-direction pole head pair, the Y-direction pole head pair, and the Z-direction pole head pair. When the capacitive anti-vibration sensor is in a vibration environment, the displacement directions of the axisymmetric diaphragms caused by the vibration are the same, and the displacement directions of the axisymmetric diaphragms caused by the sound pressure are opposite.

[0043] The processing circuit includes six inputs, which are used to convert the capacitance signals of each channel into voltage changes after impedance transformation, and use the adder carried in the processing circuit to perform vibration noise cancellation processing and infrasound sound pressure calculation.

[0044] In the embodiment of the present application, the consistency requirements of each axisymmetric diaphragm are high to minimize the noise caused by asymmetry. The capacitance value formed by the diaphragm and the back plate is 150pf±1pf, and the resonance frequency of the diaphragm is 1kHz±10Hz.

[0045] See also Figure 5 , Figure 5 A flow chart of a signal processing method using a capacitive anti-vibration infrasound sensor provided in an embodiment of the present application is shown in FIG. Figure 5 As shown, the specific steps include the following steps.

[0046] Step S502: when the vibration direction of the environment in which the capacitive anti-vibration infrasound sensor is located is upward, obtaining a first output signal value corresponding to a first pole head in the Z-direction pole head pair and a second output signal value corresponding to a second pole head, wherein when the vibration direction is upward, a first diaphragm corresponding to the first pole head in the Z-direction pole head pair is convex, and a second diaphragm corresponding to the second pole head is concave;

[0047] Step S504: obtaining a third output signal value corresponding to the first pole head in the X-direction pole head pair, and a fourth output signal value corresponding to the second pole head, wherein, when the vibration direction is upward, the upper half of the third diaphragm corresponding to the first pole head in the X-direction pole head pair is concave and the lower half is convex, and the upper half of the fourth diaphragm corresponding to the second pole head is convex and the lower half is concave;

[0048] Step S506: using an adder in the processing circuit to process the first output signal value and the second output signal value to perform vibration noise cancellation and sound pressure calculation;

[0049] Step S508: using an adder in the processing circuit to process the third output signal value and the fourth output signal value to perform vibration noise cancellation and sound pressure calculation.

[0050] In practical applications, when the vibration direction of the sensor is upward, such as Figure 6 As shown in the figure, the responses of the Z-direction pole head and the pole head diaphragm to upward vibration are opposite, the first pole head diaphragm is convex and the second pole head diaphragm is concave, and the output signals of the two pole heads can be offset numerically by direct summation. For the pole heads in the X direction on both sides, when the sensor vibrates upward, since the density distribution of the gas in the cavity in the vertical direction has a certain gradient, the diaphragms corresponding to the first pole head and the second pole head will appear similar to the situation of the upper part being concave and the lower part being convex. Since the average distance change of the diaphragm to the rear plate is small, the change of the capacitance of the pole head in the X direction can be ignored when vibrating upward.

[0051] The sensor works in the infrasound frequency band, with an operating frequency band of 0.01Hz-20Hz. The size of the sensor is 10cm×10cm×10cm, which is much smaller than the wavelength of the sound wave in the operating frequency band (17m), so it can be simplified as a particle in acoustic analysis.

[0052] join Figure 7 , Figure 7A flow chart of another signal processing method using a capacitive anti-vibration infrasound sensor provided in an embodiment of the present application

[0053] Step S702: When the capacitive anti-vibration infrasound sensor is in a non-vibration condition, the output signal value corresponding to each of the pole heads in the X-direction pole head pair, the Y-direction pole head pair, and the Z-direction pole head pair is respectively obtained, wherein, when the external sound pressure changes in the non-vibration condition, the diaphragm corresponding to each of the pole heads in the X-direction pole head pair, the Y-direction pole head pair, and the Z-direction pole head pair is synchronously concave or convex;

[0054] Step S704: using the adder in the processing circuit to process each output signal value obtained, and perform vibration noise cancellation and sound pressure calculation.

[0055] like Figure 8 As shown in the figure, under vibration-free conditions, when the external sound pressure P changes, the vibration responses of the diaphragms of the three-axis poles of the sensor are similar, and each diaphragm is concave or convex synchronously, so the output signals of the poles can be numerically superimposed and processed.

[0056] The vibration-resistant infrasound sensor designed by the present invention utilizes the different response characteristics of three groups of symmetrical diaphragms to vibration and sound pressure, numerically sums the output signals of the diaphragms of each axis, and offsets the output signals caused by vibration, thereby reducing the acceleration sensitivity of the sensor and improving the vibration resistance. Using this vibration-resistant infrasound sensor, when the sound pressure sensitivity is 12.5mV / Pa, the acceleration sensitivity can be reduced from 10mV / (ms-2) to 2.5mV / (ms-2), meeting the infrasound measurement requirements in a vibration environment.

[0057] In an embodiment of the present application, the adder in the processing circuit is used to process the obtained output signal values ​​to cancel vibration noise and calculate sound pressure, including: performing impedance transformation on six channels and three groups of signals, and outputting voltage signals corresponding to each input respectively; summing the six groups of output voltage signals to determine the sound pressure value; and determining the real voltage signal based on the sound pressure value.

[0058] It should be noted that in the embodiment of the present application, the processing circuit includes six inputs, each of which has an impedance conversion function. The capacitance signals of each channel are converted into voltage changes after impedance conversion, and then the adder and subtractor in the circuit are used to achieve vibration noise cancellation and infrasound sound pressure calculation. The vibration signal cancellation and sound pressure calculation process is as follows: 1) impedance conversion is performed on six channels and three groups of signals, and voltage signals V1-V6 are output; 2) the six groups of signals are added to obtain 6 times the sound pressure value Vsum; 3) Vsum is divided by 6 to obtain the real sound pressure signal V.

[0059] The capacitive anti-vibration infrasound sensor provided by the embodiment of the present application adopts a regular hexahedron structure and designs three sets of symmetrical diaphragms in three orthogonal directions. When the sensor is in a vibrating environment, the displacement directions of the symmetrical diaphragms caused by the vibration are the same, and the displacement directions of the symmetrical diaphragms caused by the sound pressure are opposite, so the vibration component can be offset by an algorithm, thereby reducing the acceleration sensitivity of the sensor and improving the anti-vibration capability.

[0060] It should be noted that the above is a description of a specific embodiment of the present specification. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recorded in the claims can be performed in an order different from that in the embodiments and still achieve the desired results. In addition, the processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required by the embodiments of the present specification.

[0061] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0062] The preferred embodiments of this specification disclosed above are only used to help explain this specification. The optional embodiments do not describe all the details in detail, nor do they limit the invention to only the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of the embodiments of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the embodiments of this specification, so that technicians in the relevant technical field can well understand and use this specification. This specification is only limited by the claims and their full scope and equivalents.

Claims

1. A capacitive anti-vibration infrasound sensor, characterized in that: include: An X-direction pole head pair, a Y-direction pole head pair, a Z-direction pole head pair and a processing circuit; The X-direction pole head pair, the Y-direction pole head pair, and the Z-direction pole head pair are arranged in three orthogonal directions of the capacitive vibration infrasound sensor, and are used to sense infrasound waves and vibration signals in the X-direction, Y-direction, and Z-direction directions, wherein three groups of symmetrical diaphragms are respectively arranged on the X-direction pole head pair, the Y-direction pole head pair, and the Z-direction pole head pair, and when the capacitive anti-vibration sensor is in a vibration environment, the displacement directions of the symmetrical diaphragms caused by the vibration are the same, and the displacement directions of the symmetrical diaphragms caused by the sound pressure are opposite; The processing circuit includes six inputs, which are used to convert the capacitance signals of each channel into voltage changes after impedance transformation, and use the adder carried in the processing circuit to perform vibration noise cancellation processing and infrasound sound pressure calculation.

2. The capacitive anti-vibration infrasound sensor according to claim 1, characterized in that: The capacitive anti-vibration infrasound sensor adopts a regular hexahedron structure.

3. The capacitive anti-vibration infrasound sensor according to claim 1, characterized in that: The capacitive anti-vibration infrasound sensor also includes: a bracket, a back plate, a pressure equalizing hole, an inner cavity, a frame, a support point and a rear cavity; The capacitance values ​​of the axisymmetric diaphragm and the back plate are 150 pf±1 pf, and the resonance frequency of the diaphragm is 1 kHz±10 Hz.

4. A signal processing method using a capacitive anti-vibration infrasound sensor as claimed in claim 1, characterized in that: include: When the vibration direction of the environment in which the capacitive anti-vibration infrasound sensor is located is upward, a first output signal value corresponding to a first pole head in the Z-direction pole head pair and a second output signal value corresponding to a second pole head are obtained, wherein, when the vibration direction is upward, a first diaphragm corresponding to the first pole head in the Z-direction pole head pair is convex, and a second diaphragm corresponding to the second pole head is concave; Obtain a third output signal value corresponding to the first pole head in the X-direction pole head pair, and a fourth output signal value corresponding to the second pole head, wherein, when the vibration direction is upward, the upper half of the third diaphragm corresponding to the first pole head in the X-direction pole head pair is concave and the lower half is convex, and the upper half of the fourth diaphragm corresponding to the second pole head is convex and the lower half is concave; Using an adder in a processing circuit, the first output signal value and the second output signal value are processed to cancel vibration noise and calculate sound pressure; The third output signal value and the fourth output signal value are processed by an adder in the processing circuit to perform vibration noise cancellation and sound pressure calculation.

5. The method according to claim 4, characterized in that The method further comprises: When the capacitive anti-vibration infrasound sensor is in a non-vibration condition, the output signal value corresponding to each pole head in the X-direction pole head pair, the Y-direction pole head pair, and the Z-direction pole head pair is respectively obtained, wherein, when the external sound pressure changes in the non-vibration condition, the diaphragm corresponding to each pole head in the X-direction pole head pair, the Y-direction pole head pair, and the Z-direction pole head pair is synchronously concave or convex; The adder in the processing circuit is used to process the obtained output signal values ​​to cancel vibration noise and calculate sound pressure.

6. The method according to any one of claims 4 or 5, characterized in that: The method uses an adder in the processing circuit to process each output signal value to cancel vibration noise and calculate sound pressure, including: Perform impedance transformation on six channels and three groups of signals, and output voltage signals corresponding to each input respectively; Summing the six groups of output voltage signals to determine the sound pressure value; Based on the sound pressure value, a real voltage signal is determined.

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