A rotary compact sound level meter automatic calibration device and method

Abstract

The present invention discloses a rotary compact sound level meter automatic calibration device and method, the device comprising: a sound level meter with a flexibly adjustable position; a sound pressure calibrator with a fixed position; an automatic position adjustment device for the sound level meter, used to support the sound level meter and automatically adjust the position of the sound level meter during calibration; a main control unit, used to coordinate and control the operation of the automatic position adjustment device of the sound level meter, realize the position adjustment of the sound level meter, and perform data collection and analysis of the sound level meter and the sound pressure calibrator, and then calibrate the sound level meter. The present invention only designs one set of position adjustment equipment, and through the improvement of the system structure, it greatly reduces the space occupied by the system, reduces the cost, reduces the requirements for the processing and assembly accuracy of the control system, and improves the overall stability of the system.

Description

Technical Field

[0001] The invention relates to the technical field of sound level meter calibration, and in particular to an automatic calibration device and method for a rotary compact sound level meter. Background Art

[0002] Sound level meters are common instruments used in environmental monitoring and occupational health testing. Since the readings of sound level meters will drift after being used for a period of time, users need to calibrate the sound level meters periodically to ensure the accuracy of their readings.

[0003] There are two common ways to use sound level meters: one is to use the instrument manually for short-term on-site monitoring, and the other is to use an online monitoring system to conduct long-term online monitoring of the monitoring environment.

[0004] In the first case, the user can calibrate the sound level meter with a sound level meter calibrator before each monitoring. In the second case, the monitoring instrument is usually installed in a monitoring box high above the ground, so it is difficult to perform manual calibration periodically, and auxiliary equipment such as ladders or lifts are usually required.

[0005] The applicant has disclosed a sound level meter automatic calibration system in a patent document with patent number 201911154091.3 and titled "An automatic calibration device and method for a sound level meter", which is used to periodically and automatically calibrate the sound level meter installed in a monitoring box higher than the ground, thereby avoiding the trouble of manual operation. The system drives the automatic position adjustment device of the sound level meter and the automatic position adjustment device of the sound pressure calibrator through the main control unit, and adjusts the positions of the sound level meter and the sound pressure calibrator respectively, so that during calibration, the sound pressure calibrator is directly placed on the microphone of the sound level meter to calibrate the sound level meter. After the calibration is completed, the sound level meter and the sound pressure calibrator return to their original positions.

[0006] However, the inventors of this application found that the above technology has at least the following technical problems in the process of implementing the technical solution of the invention in the embodiment of this application:

[0007] 1. Both the sound level meter microphone and the sound pressure calibrator need to be adjusted in position, so they are both moving parts. Two sets of position adjustment equipment are required. The equipment occupies a large space and the size of the overall system box is large.

[0008] 2. The movement of the sound level meter microphone and the sound pressure calibrator is controlled by using a servo motor plus a module, which is relatively expensive.

[0009] 3. Since both the sound level meter microphone and the sound pressure calibrator have motion trajectories, any deviation in either motion will affect the working results of the entire system, and the guarantee of motion accuracy is entirely dependent on the rotation of the motor and the processing and assembly accuracy of the system. Therefore, the processing and assembly requirements of the entire system are relatively high. Summary of the invention

[0010] The embodiment of the present application solves the technical problems in the prior art that the automatic calibration device of the sound level meter occupies a large space, has a high cost, and has high processing and assembly requirements by providing a rotary compact sound level meter automatic calibration device. Only one set of position adjustment equipment is designed, and through the improvement of the system structure, the space occupied by the system is greatly reduced, the cost is reduced, the requirements for the processing and assembly accuracy of the control system are reduced, and the overall stability of the system is improved.

[0011] The embodiment of the present application provides a rotary compact sound level meter automatic calibration device, comprising:

[0012] Sound level meter with flexible position adjustment;

[0013] A fixed-position sound pressure calibrator;

[0014] A sound level meter position automatic adjustment device, used for supporting the sound level meter and automatically adjusting the position of the sound level meter during calibration;

[0015] The main control unit is used to coordinate and control the operation of the automatic position adjustment device of the sound level meter, realize the position adjustment of the sound level meter, and collect and analyze the data of the sound level meter and the sound pressure calibrator, so as to calibrate the sound level meter.

[0016] Preferably, during calibration, the main control unit controls the sound level meter position automatic adjustment device to automatically adjust the position of the sound level meter, inserts the microphone of the sound level meter into the sound pressure calibrator for calibration, and resets the sound level meter after the calibration is completed.

[0017] Preferably, the device also includes a monitoring box, the sound pressure calibrator is fixedly embedded on the outer shell of the monitoring box, the sound pressure calibrator is partially exposed to the outside of the monitoring box, and the sound source hole of the sound pressure calibrator is located in the monitoring box; the sound level meter position automatic adjustment device is arranged inside the monitoring box, and is connected to the sound level meter through the monitoring box.

[0018] Preferably, the sound level meter position automatic adjustment device includes a sound level meter support shaft, one end of the sound level meter support shaft passes through the monitoring box and is connected to the sound level meter, the other end of the sound level meter support shaft is fixed on an eccentric base, the eccentric base is fixed on a tray through a rotating gear mechanism and is connected to a rotating motor; the tray is close to the end of the rack, and the rack is connected to the lifting motor through a lifting gear.

[0019] More preferably, the rotating gear mechanism comprises a first rotating gear and a second rotating gear meshing with each other, the eccentric base is fixedly connected to the first rotating gear, the first rotating gear is fixed on the tray, and the second rotating gear is connected to the rotating motor.

[0020] Furthermore, the rack is coaxially arranged in the lifting slot so as to be liftable.

[0021] Furthermore, a track groove for protecting and guiding the sound level meter to move along a set track is provided on the side of the sound level meter position automatic adjustment device.

[0022] Furthermore, a limiting mechanism is provided at the extreme position of the track groove.

[0023] The present invention also provides a sound level meter automatic calibration method, characterized in that the above-mentioned rotary compact sound level meter automatic calibration device is used, and the steps are as follows:

[0024] Adjust the sound level meter so that it is in calibration mode;

[0025] Turn on the sound pressure calibrator to generate a standard sound source;

[0026] Control the automatic position adjustment device of the sound level meter to work, insert the microphone of the sound level meter into the sound source hole of the sound pressure calibrator, and calibrate the sound level meter;

[0027] After calibration is complete, reset the sound level meter and switch to test mode to continue normal data monitoring.

[0028] Preferably, in one calibration cycle, the action process of the automatic position adjustment device of the sound level meter is as follows:

[0029] In the initial state, the sound level meter is in monitoring mode, and the microphone of the sound level meter is in the working position outside the monitoring box;

[0030] After calibration begins, the main control unit triggers the lifting motor to withdraw the microphone of the sound level meter into the monitoring box;

[0031] The main control unit triggers the rotary motor to rotate the eccentric base, bringing the microphone of the sound level meter under the sound source hole of the sound pressure calibrator;

[0032] The main control unit triggers the lifting motor to reverse, so that the microphone of the sound level meter is inserted into the sound source hole of the sound pressure calibrator to calibrate the sound level meter;

[0033] After the calibration is completed, the main control unit triggers the lifting motor to work, and withdraws the microphone of the sound level meter from the sound source hole of the sound pressure calibrator to below the sound source hole of the sound pressure calibrator;

[0034] The main control unit triggers the rotary motor to reverse, rotating the eccentric base back to its original position, so that the microphone of the sound level meter returns to the bottom of the working position;

[0035] Finally, the main control unit triggers the lifting motor to reverse, so that the microphone of the sound level meter returns to the working position.

[0036] One or more technical solutions provided in the embodiments of the present application have at least the following technical effects or advantages:

[0037] 1. The sound pressure calibrator is fixed in a fixed position so that it can be embedded outside the monitoring box, which can effectively save the internal space of the monitoring box and effectively reduce the lifting stroke of the sound level meter microphone, so the overall box size can be effectively reduced.

[0038] 2. The sound pressure calibrator adopts a fixed position and only uses one set of position adjustment equipment, so there is only one set of motion trajectory. Compared with the traditional two sets of motion trajectories, the control is simpler and more convenient.

[0039] 3. By improving the mechanical structure of the system, the traditional servo motor plus module method used to control the movement of the sound pressure calibrator and the sound level meter is replaced by an ordinary rotary motor drive, which can save costs and provide a wider range of motor choices.

[0040] 4. Setting mechanical limits during the rotation of the eccentric chassis and the up and down sliding of the sound level meter can reduce the requirements for the processing and assembly accuracy of the control system, and ensure the overall stability of the calibration system by relying on the high stability of the mechanical structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a structural schematic diagram of the automatic calibration device of a rotary compact sound level meter provided in an embodiment of the present application (initial state, monitoring position);

[0042] Figure 2 A schematic diagram of a control system for a rotary compact sound level meter automatic calibration device provided in an embodiment of the present application;

[0043] Figure 3 This is a schematic diagram of the microphone of the sound level meter in the embodiment of the present application being retracted into the monitoring box;

[0044] Figure 4 This is a schematic diagram of the microphone of the sound level meter in the embodiment of the present application being rotated to below the sound source hole of the sound pressure calibrator;

[0045] Figure 5 This is a schematic diagram of the microphone of the sound level meter in the embodiment of the present application being inserted into the sound source hole of the sound pressure calibrator;

[0046] Figure 6This is a schematic diagram of the microphone of the sound level meter in the embodiment of the present application being retracted to the lower part of the sound source hole of the sound pressure calibrator;

[0047] Figure 7 This is a schematic diagram of the microphone of the sound level meter rotating back to its original position in an embodiment of the present application;

[0048] Figure 8 This is a schematic diagram of the microphone of the sound level meter in an embodiment of the present application returning to the monitoring position. DETAILED DESCRIPTION

[0049] The embodiment of the present application solves the technical problems in the prior art that the automatic calibration device of the sound level meter occupies a large space, has a high cost, and has high processing and assembly requirements by providing a rotary compact sound level meter automatic calibration device. By improving the system structure, the space occupied by the system is greatly reduced, the cost is reduced, the requirements for the processing and assembly accuracy of the control system are reduced, and the overall stability of the system is improved.

[0050] The technical solution in the embodiment of the present application is to solve the above-mentioned crosstalk problem, and the overall idea is as follows:

[0051] The sound pressure calibrator adopts a fixed position, and only a set of position adjustment equipment is designed for the sound level meter microphone. During calibration, the microphone is retracted a short distance, rotated to the bottom of the sound pressure calibrator, and then inserted into the sound source hole of the sound pressure calibrator for calibration. After calibration, the microphone is withdrawn from the sound source hole of the sound pressure calibrator and rotated back to its original position.

[0052] Since the sound pressure calibrator is fixed in position, it can be embedded outside the main box, which effectively saves the internal space of the box. It can also effectively reduce the longitudinal travel of the microphone, so the overall box size can be effectively reduced.

[0053] By improving the mechanical structure and adopting a rotatable eccentric chassis and slide combination, the position adjustment device of the sound level meter microphone can be driven by an ordinary rotary motor without the need for a servo motor, which can save costs and provide a wider range of motor choices.

[0054] Since there is only one set of position adjustment equipment, there is only one set of motion trajectory. Furthermore, mechanical limits can be set in the rotation of the eccentric chassis and the up and down sliding of the sound level meter, which can reduce the requirements for the processing and assembly accuracy of the control system and ensure the overall stability of the calibration system by relying on the high stability of the mechanical structure.

[0055] In order to better understand the above technical solution, the following will be combined with the accompanying drawings and specific

[0056] Figure 1This is a structural schematic diagram of a rotary compact sound level meter automatic calibration device provided in an embodiment of the present application, wherein the rotary compact sound level meter automatic calibration device comprises:

[0057] Sound level meter 1, the position of sound level meter 1 can be flexibly adjusted;

[0058] A sound pressure calibrator 2, the position of the sound pressure calibrator 2 is fixed;

[0059] The sound level meter position automatic adjustment device 3 is used to support the sound level meter 1 and automatically adjust the position of the sound level meter 1 during calibration, insert the microphone of the sound level meter 1 into the sound pressure calibrator 2 for calibration, and reset the sound level meter 1 after the calibration is completed;

[0060] A monitoring box 4, used for assembling a sound level meter 1, a sound pressure calibrator 2 and an automatic position adjustment device 3 for the sound level meter;

[0061] The main control unit 5 is connected to the sound level meter 1, the sound pressure calibrator 2, and the sound level meter position automatic adjustment device 3, and is used to coordinate and control the operation of the sound level meter position automatic adjustment device 3, and to collect and analyze data of the sound level meter 1 and the sound pressure calibrator 2, and to modify the adjustment coefficient of the sound level meter 1.

[0062] In this embodiment, the sound level meter 1 is composed of a microphone, a preamplifier, a data processing module and a noise level display module connected in sequence. The microphone converts the sound into an electrical signal, which is then amplified by the preamplifier and sent to the data processing module for processing and analysis to obtain the value of the noise level, which is then displayed by the noise level display module.

[0063] The microphone and the preamplifier are integrated together to form a microphone. The data processing module and the noise level display module are integrated together to form a sound level meter control unit. The microphone is connected to the sound level meter control unit through an extension line.

[0064] In this embodiment, the sound pressure calibrator 2 is also called a sound level calibrator, which is used to generate one or more known sound pressure levels at one or more specified frequencies, and then measure the sound pressure sensitivity of a microphone of a specified model structure.

[0065] The sound pressure calibrator 2 is fixedly embedded on the outer shell of the monitoring box 4 , a part of the sound pressure calibrator 2 is exposed outside the monitoring box 4 , and a sound source hole of the sound pressure calibrator 2 is located inside the monitoring box 4 .

[0066] As a preferred embodiment, a rainproof device is provided above the sound pressure calibrator 2 .

[0067] In this embodiment, the sound level meter position automatic adjustment device 3 is composed of a sound level meter support shaft 31, an eccentric base 32, a bearing 33, a first rotating gear 34, a tray 35, a second rotating gear 36, a rotating motor 37, a rack 38, a lifting slide 39, a lifting gear 310, a lifting motor 311 and other components.

[0068] The upper end of the sound level meter support shaft 31 passes through the monitoring box 4 and is connected to the sound level meter 1 , and other components of the sound level meter position automatic adjustment device 3 are arranged inside the monitoring box 4 .

[0069] The lower end of the sound level meter support shaft 31 is fixed to the eccentric base 32, and the eccentric base 32 is fixedly connected to the first rotating gear 34, and the first rotating gear 34 is fixed to the tray 35. The first rotating gear 34 is meshed with the second rotating gear 36, and the second rotating gear 36 is connected to the rotating motor 37. Bearings 33 are provided at both ends of the first rotating gear 34, so that the friction force when the first rotating gear 34 rotates can be reduced.

[0070] The upper end of the rack 38 is close to the tray 35, but the two are not fixedly connected. The rack 38 is coaxially arranged in the lifting slide 39, and the rack 38 is meshed with the lifting gear 310 to form a gear rack mechanism, and the lifting gear 310 is connected to the lifting motor 311.

[0071] When the automatic position adjustment device 3 of the sound level meter is working, the rotating motor 37 drives the sound level meter 1 to rotate, and the lifting motor 311 drives the sound level meter 1 to lift. The details are as follows:

[0072] The rotating motor 37 works to drive the second rotating gear 36 to rotate, which drives the first rotating gear 34 to rotate, and the eccentric base 32 and the tray 35 to rotate accordingly, which drives the sound level meter 1 to rotate. Since the rack 38 is coaxially arranged with the tray 35 but not fixedly connected, the tray 35 is allowed to rotate without driving the rack 38 to rotate.

[0073] The rack 38 can move up and down in the lifting chute 39, and the lifting movement of the rack 38 is driven by the lifting motor 311 and completed by the gear rack mechanism. That is, the lifting motor 311 works to drive the lifting gear 310 to rotate, driving the rack 38 to move up and down in the lifting chute 39.

[0074] In this embodiment, the main control unit 5 can be an industrial computer, a Raspberry Pi or a single-chip microcomputer. Figure 2 The main control unit 5 is connected to the sound level meter 1, the sound pressure calibrator 2, the rotating motor 37, and the lifting motor 311. The main control unit 5 controls the operation of the rotating motor 37 and the lifting motor 311 to adjust the position of the sound level meter 1. The main control unit 5 also collects and analyzes data of the sound level meter 1 and the sound pressure calibrator 2 and modifies the adjustment coefficient of the sound level meter 1.

[0075] As a preferred embodiment, the main control unit 5 is also connected to the remote control terminal via a wireless transmission module to send the real-time collected data and calibration results to the remote control terminal.

[0076] The specific working method of the automatic calibration device for a rotary compact sound level meter provided in this embodiment is as follows:

[0077] Step S1: adjusting the sound level meter 1 to be in a calibration mode;

[0078] Step S2: Turn on the sound pressure calibrator 2 to generate a standard sound source; usually the standard sound source is 1kHz, 96dB or 1kHz, 114dB;

[0079] Step S3: Control the automatic position adjustment device 3 of the sound level meter to work, and insert the microphone of the sound level meter 1 into the sound source hole of the sound pressure calibrator 2;

[0080] Step S4: notify the sound level meter 1 that the current input signal is a standard signal (96dB or 114dB), the microphone of the microphone of the sound level meter 1 collects the standard signal, and gives the value of the noise level after processing by the internal data processing module; compare the value given by the sound level meter 1 with the standard signal sent by the sound pressure calibrator 2, if there is a deviation, calculate an adjustment coefficient according to the deviation, write it into the internal data processing module of the sound level meter 1, and finally achieve the consistency between the reading of the sound level meter 1 and the value of the sound pressure calibrator 2, and complete the first calibration of the sound level meter;

[0081] Step S5: Switch the sound level meter to the test mode and continue to monitor the data.

[0082] Among them, there is no order of precedence for step S1, step S2, and step S3, and the steps can be swapped.

[0083] During the specific operation, the user is allowed to set a calibration at a fixed interval. When the system triggers calibration, the main control unit sets the sound level meter to calibration mode, and drives the rotating motor and lifting motor to calibrate through the control card. After the calibration is completed, the system automatically switches the sound level meter to test mode to continue monitoring data.

[0084] During the calibration process, the specific steps of the automatic position adjustment device 3 of the sound level meter are as follows:

[0085] In the initial state, the sound level meter 1 is in the monitoring mode, and the microphone of the sound level meter 1 is outside the monitoring box 4. Figure 1 As a preferred embodiment, a hollow sleeve 41 is provided on the monitoring box 4 to limit and protect the up and down movement of the sound level meter microphone. The upper end of the sound level meter support shaft 31 passes through the hollow sleeve 41 and is connected to the sound level meter 1.

[0086] After starting calibration, the sound level meter 1 is set to the calibration mode and the sound pressure calibrator 2 is triggered to emit a standard sound.

[0087] The main control unit 5 triggers the lifting motor 311 to work, so that the microphone of the sound level meter 1 is withdrawn into the monitoring box 4. Figure 3 shown.

[0088] Then, the main control unit 5 triggers the rotating motor 37 to work, so that the eccentric base 32 rotates, and the microphone of the sound level meter 1 is brought under the sound source hole of the sound pressure calibrator 2, as shown in FIG. Figure 4 shown.

[0089] Then, the main control unit 5 triggers the lifting motor 311 to reverse, so that the microphone of the sound level meter 1 is inserted into the sound source hole of the sound pressure calibrator 2. Figure 5 As shown. And send a command to the sound level meter 1 to perform calibration.

[0090] After the calibration is completed, the main control unit 5 triggers the lifting motor 311 to work, and the microphone of the sound level meter 1 is withdrawn from the sound source hole of the sound pressure calibrator 2. Figure 6 shown.

[0091] Then, the main control unit 5 triggers the rotary motor 37 to reverse, and rotates the eccentric base 32 back to its original position again, so that the microphone of the sound level meter 1 returns to the lower part of the working position. Figure 7 shown.

[0092] Finally, the main control unit 5 triggers the lifting motor 311 to reverse, so that the microphone of the sound level meter 1 returns to the working position. Figure 8 As shown in the figure, the sound level meter 1 is set to monitoring mode through the command to complete a full calibration cycle.

[0093] As a preferred embodiment, a limit mechanism is provided at the limit positions of the up-and-down movement and the rotational movement of the sound level meter to achieve limit control of the movement position of the sound level meter.

[0094] As a preferred embodiment, a rotation track groove and a lifting track groove are set on one side of the sound level meter position automatic adjustment device to protect the sound level meter position automatic adjustment device from moving along the set track groove to prevent the system from derailing.

[0095] The technical solutions in the above embodiments of the present application have at least the following technical effects or advantages:

[0096] 1. The sound pressure calibrator is fixed in a fixed position so that it can be embedded outside the monitoring box, which can effectively save the internal space of the monitoring box and effectively reduce the lifting stroke of the sound level meter microphone, so the overall box size can be effectively reduced.

[0097] 2. The sound pressure calibrator adopts a fixed position and only uses one set of position adjustment equipment, so there is only one set of motion trajectory. Compared with the traditional two sets of motion trajectories, the control is simpler and more convenient.

[0098] 3. By improving the mechanical structure of the system, the traditional servo motor plus module method used to control the movement of the sound pressure calibrator and the sound level meter is replaced by an ordinary rotary motor drive, which can save costs and provide a wider range of motor choices.

[0099] 4. Setting mechanical limits during the rotation of the eccentric chassis and the up and down sliding of the sound level meter can reduce the requirements for the processing and assembly accuracy of the control system, and ensure the overall stability of the calibration system by relying on the high stability of the mechanical structure.

[0100] It should be understood that although the terms "first", "second", etc. may be used herein to describe various units, these units should not be limited by these terms. These terms are used only to distinguish one unit from another. For example, a first unit may be referred to as a second unit, and similarly, a second unit may be referred to as a first unit without departing from the scope of the exemplary embodiments.

[0101] The directional terms such as up, down, left, right, front, back, front, back, top, bottom, etc. mentioned or may be mentioned in this specification are defined relative to the structures shown in the drawings. They are relative concepts and may change accordingly according to different positions and different usage conditions. Therefore, these or other directional terms should not be interpreted as restrictive terms.

[0102] The above is only a preferred embodiment of the present application, and is not any formal or substantial limitation to the present application. It should be pointed out that ordinary technicians in this technical field can make several improvements and supplements without departing from the method of the present application, and these improvements and supplements should also be regarded as the protection scope of the present application. Any technician familiar with this profession can make some changes, modifications and evolutions of the technical content disclosed above without departing from the spirit and scope of the present application, which are equivalent embodiments of the present application; at the same time, any changes, modifications and evolutions of any equivalent changes made to the above embodiments based on the substantial technology of the present application are still within the scope of the technical solution of the present application.

Claims

1. A rotary compact sound level meter automatic calibration device, characterized in that: include: A sound level meter with a flexibly adjustable position (1); A fixed-position sound pressure calibrator (2); A sound level meter position automatic adjustment device (3) for supporting the sound level meter (1) and automatically adjusting the position of the sound level meter (1) during calibration; A main control unit (5) is used to coordinate and control the operation of the automatic position adjustment device (3) of the sound level meter, realize the position adjustment of the sound level meter (1), and collect and analyze data of the sound level meter (1) and the sound pressure calibrator (2), so as to calibrate the sound level meter (1); It also comprises a monitoring box (4), the sound pressure calibrator (2) is fixedly mounted on the outer shell of the monitoring box (4), the sound pressure calibrator (2) is partially exposed outside the monitoring box (4), and the sound source hole of the sound pressure calibrator (2) is located inside the monitoring box (4); the sound level meter position automatic adjustment device (3) is arranged inside the monitoring box (4), and passes through the monitoring box (4) to be connected to the sound level meter (1); The sound level meter position automatic adjustment device (3) comprises a sound level meter support shaft (31), one end of the sound level meter support shaft (31) passes through the monitoring box (4) and is connected to the sound level meter (1), and the other end of the sound level meter support shaft (31) is fixed on an eccentric base (32), and the eccentric base (32) is fixed on a tray (35) through a rotating gear mechanism and is connected to a rotating motor (37); the tray (35) is closely attached to the end of a rack (38), and the rack (38) is connected to a lifting motor (311) through a lifting gear (310); During calibration, the main control unit (5) controls the sound level meter position automatic adjustment device (3) to automatically adjust the position of the sound level meter (1), inserts the microphone of the sound level meter (1) into the sound pressure calibrator (2) for calibration, and resets the sound level meter (1) after the calibration is completed.

2. The automatic calibration device for a rotary compact sound level meter according to claim 1, characterized in that: The rotating gear mechanism comprises a first rotating gear (34) and a second rotating gear (36) meshing with each other, the eccentric base (32) is fixedly connected to the first rotating gear (34), the first rotating gear (34) is fixed on the tray (35), and the second rotating gear (36) is connected to the rotating motor (37).

3. The automatic calibration device for a rotary compact sound level meter according to claim 1, characterized in that: The rack (38) is coaxially arranged in the lifting slide groove (39) so as to be liftable.

4. The automatic calibration device for a rotary compact sound level meter according to claim 1, characterized in that: A track groove for protecting and guiding the sound level meter (1) to move along a set track is provided on the side of the sound level meter position automatic adjustment device (3).

5. The automatic calibration device for a rotary compact sound level meter according to claim 4, characterized in that: A limiting mechanism is provided at the extreme position of the track groove.

6. A method for automatic calibration of a sound level meter, characterized in that: Using the automatic calibration device for a rotary compact sound level meter as described in any one of claims 1 to 5, the steps are: Adjust the sound level meter (1) to the calibration mode; Turning on the sound pressure calibrator (2) to generate a standard sound source; Controlling the automatic position adjustment device (3) of the sound level meter to work, inserting the microphone of the sound level meter (1) into the sound source hole of the sound pressure calibrator (2), and calibrating the sound level meter (1); After calibration is complete, reset the sound level meter (1) and switch to test mode to continue normal data monitoring.

7. The automatic calibration method for a sound level meter according to claim 6, characterized in that: In one calibration cycle, the specific operation process of the sound level meter position automatic adjustment device (3) is as follows: In the initial state, the sound level meter (1) is in a monitoring mode, and the microphone of the sound level meter (1) is in a working position outside the monitoring box (4); After calibration begins, the main control unit (5) triggers the lifting motor (311) to operate, so that the microphone of the sound level meter (1) is withdrawn into the monitoring box (4); The main control unit (5) triggers the rotating motor (37) to work, so that the eccentric base (32) rotates, and the microphone of the sound level meter (1) is brought below the sound source hole of the sound pressure calibrator (2); The main control unit (5) triggers the lifting motor (311) to reverse, so that the microphone of the sound level meter (1) is inserted into the sound source hole of the sound pressure calibrator (2), and the sound level meter (1) is calibrated; After the calibration is completed, the main control unit (5) triggers the lifting motor (311) to work, so as to withdraw the microphone of the sound level meter (1) from the sound source hole of the sound pressure calibrator (2) to below the sound source hole of the sound pressure calibrator (2); The main control unit (5) triggers the rotary motor (37) to reverse, rotates the eccentric base (32) back to its original position, and returns the microphone of the sound level meter (1) to below the working position; Finally, the main control unit (5) triggers the lifting motor (311) to reverse, so that the microphone of the sound level meter (1) returns to the working position.

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