Optical microphone test platform and test system

Abstract

The application discloses the technical field of sensor calibration, and relates to an optical microphone test platform, a test system, a directivity test method, a non-contact frequency response test method, a minimum offset test method and a contact frequency response test method. The optical microphone test platform comprises a non-contact test platform and a contact test platform. The non-contact test platform comprises a test bench, a three-dimensional support, a rotating platform, a lifting platform, a first microphone fixing device and a reference sensor fixing device. The contact test platform comprises a test support, a test block, an optical microphone fixing support and a sound emitter fixing support. The optical microphone test platform and the test system can simultaneously complete non-contact test and contact test of a measured optical microphone, including directivity test, non-contact frequency response test, minimum offset test and contact frequency response test, and the measured product can be conveniently replaced for repeated test.

Description

Technical Field

[0001] This invention relates to the field of sensor calibration technology, specifically to an optical microphone test platform, test system and directivity test method, non-contact frequency response test method, minimum offset test method and contact frequency response test method. Background Technology

[0002] An optical microphone is a device that uses a laser beam and a reflective surface to capture sound, converting it into a digital signal for output. The working principle of an optical microphone is based on the effect of sound waves on the refractive index of a medium. Specifically, when sound pressure acts on a medium, it causes a change in the medium's refractive index. This change is transmitted to the laser beam passing through the device via a Fabry-Perot interferometer. Because the phase of the light changes due to the change in refractive index, this phenomenon is used to generate an electrical signal. Optical microphones have been successfully applied in various process control and non-destructive testing applications. Optical microphones have a wider detection range and can effectively remove the influence of low-frequency background noise, focusing on the analysis of high-frequency ultrasonic signals. However, currently, there is no comprehensive device on the market for testing and verifying the performance of optical microphones. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide an optical microphone testing platform, testing system, and methods for directional testing, non-contact frequency response testing, minimum offset testing, and contact frequency response testing. The optical microphone testing system can perform tests on the optical microphone under test, including directional testing, non-contact frequency response testing, minimum offset testing, and contact frequency response testing, and it is convenient to replace the test object and perform repeated tests.

[0004] To achieve the above objectives, the present invention is implemented using the following technical solution:

[0005] In a first aspect, the present invention provides an optical microphone testing platform, including a non-contact testing platform and a contact testing platform;

[0006] The non-contact testing platform includes a test bench 1, a three-dimensional support 2, a rotating platform 3, and a lifting platform 6;

[0007] The three-dimensional support 2 and the lifting platform 6 are both installed on the table surface of the test bench 1. The rotating platform 3 is installed on the three-dimensional support 2. The lifting platform 6 is used to install the acoustic transmitter. By adjusting the three-dimensional support 2, the rotating platform 3 and the lifting platform 6, the relative angle and relative position between the optical microphone under test and the acoustic transmitter can be changed.

[0008] The contact test platform includes a test bracket 7, a test block 8, an optical microphone fixing bracket, and an acoustic transmitter fixing bracket.

[0009] The test block 8, the optical microphone mounting bracket, and the acoustic transmitter mounting bracket are all mounted on the test bracket 7, with the optical microphone mounting bracket located at the top of the test block 8 and the acoustic transmitter mounting bracket located at the bottom of the test block 8.

[0010] Furthermore, the three-dimensional support includes at least two x-axis supports, y-axis supports, and z-axis supports;

[0011] The y-axis support is fixed to the x-axis support along the axial direction perpendicular to the x-axis support, and the y-axis support can translate along the axial direction of the x-axis support.

[0012] The z-axis bracket is fixed on the y-axis bracket along an axial direction that is perpendicular to both the x-axis bracket and the y-axis bracket, and the z-axis bracket can translate along the axial direction of the y-axis bracket.

[0013] Furthermore, it also includes a first microphone fixing device 4 and a reference sensor fixing device 5;

[0014] The first microphone fixing device 4 is installed at the center of the rotating platform 3 to fix the optical microphone under test, and the reference sensor fixing device 5 is disposed on one side of the rotating platform 3 to fix the reference sensor.

[0015] Furthermore, the first microphone fixing device includes a base, a movable clamping arm, a fixed clamping arm, a movable handle, a fixed handle, a gear, and a return spring;

[0016] The movable clamping arm and the fixed clamping arm are mounted on one side of the base, and the movable handle and the fixed handle are mounted on the other side of the base;

[0017] The root of the movable clamping arm and the root of the movable handle are respectively provided with meshing teeth. The meshing teeth of the movable clamping arm and the meshing teeth of the movable handle are parallel to each other and both mesh with the gear. Pressing the movable handle can drive the gear to rotate, thereby driving the movable clamping arm to move in the opposite direction relative to the movable handle.

[0018] The return spring is mounted on the gear. In its natural state, the return spring clamps the fixture formed by the movable clamping arm and the fixed clamping arm.

[0019] Furthermore, the optical microphone mounting bracket includes a top horizontal bracket and a second microphone mounting device, the second microphone mounting device being installed in the middle of the top horizontal bracket for mounting the optical microphone under test and the reference sensor.

[0020] Furthermore, the second microphone fixing device includes a first bolt and an optical microphone mounting head;

[0021] The optical microphone mounting head is used to mount the optical microphone under test.

[0022] The first bolt is used to adjust the distance between the optical microphone under test and the test block.

[0023] Furthermore, the acoustic emitter mounting bracket includes a bottom horizontal bracket and an acoustic emitter mounting device, wherein the acoustic emitter mounting device is installed in the middle of the bottom horizontal bracket.

[0024] Furthermore, the acoustic emitter fixing device includes an acoustic emitter mounting head and a second bolt. The acoustic emitter mounting head is used to mount the acoustic emitter, and the second bolt is used to adjust the distance between the acoustic emitter and the test block.

[0025] Secondly, the present invention provides an optical microphone testing system, including the aforementioned optical microphone testing platform, and further including an acoustic transmitter, a reference sensor, a control motor, a testing host, and a host computer;

[0026] The acoustic transmitter and the reference sensor are both mounted on the optical microphone test platform;

[0027] The control motor is electrically connected to the three-dimensional support and the rotating platform respectively, and is used to control the movement of the three-dimensional support and the rotating platform.

[0028] The test host is connected to the optical microphone under test and the reference sensor, and is used to collect the detection signals of the optical microphone under test and the reference sensor during testing.

[0029] The signal between the host computer and the test host is used to analyze the detection signal;

[0030] The test host is also connected to the control motor signal, and the control motor is controlled by the host computer through the test host.

[0031] Furthermore, the test host includes signal acquisition equipment and a wideband amplifier;

[0032] The signal acquisition device is used to acquire the detection signals of the optical microphone under test and the reference sensor during testing;

[0033] The broadband amplifier is used to enhance the detection signal when the optical microphone under test and the reference sensor are tested.

[0034] Thirdly, the present invention provides a method for testing the directivity of an optical microphone, implemented based on the aforementioned optical microphone testing system, comprising the following steps:

[0035] The optical microphone and acoustic transmitter under test are pre-installed, wherein the acoustic transmitter is a single-frequency sound source. The three-dimensional support 2 and the lifting platform 6 are adjusted to make the optical microphone and acoustic transmitter under test coaxial.

[0036] Drive the acoustic transmitter to emit an acoustic signal of the same frequency;

[0037] Control the rotating platform 3 to rotate, and collect the signal of the optical microphone under test once every preset angle;

[0038] The signals from a series of tested optical microphones were analyzed to obtain the directional test results of the optical microphones.

[0039] Fourthly, the present invention provides a non-contact frequency response testing method for an optical microphone, implemented based on the aforementioned optical microphone testing system, comprising the following steps:

[0040] The optical microphone under test, the reference sensor, and the acoustic emitter are pre-installed, wherein the acoustic emitter is a broadband sound source. The three-dimensional support 2 and the lifting platform 6 are adjusted so that the symmetrical center axis of the optical microphone under test and the reference sensor is coaxial with the center point of the acoustic emitter.

[0041] Drive the acoustic transmitter to emit acoustic signals of different frequencies;

[0042] Acquire signals from the optical microphone under test and the reference sensor;

[0043] The acquired signal of the optical microphone under test is analyzed, and the frequency response curve of the optical microphone under test is obtained by using the signal of the reference sensor as a reference.

[0044] Fifthly, the present invention provides a minimum offset testing method for an optical microphone, implemented based on the aforementioned optical microphone testing system, comprising the following steps:

[0045] The optical microphone and acoustic transmitter under test are pre-installed. The positions of the three-dimensional support 2 and the laser vibrometer are adjusted so that the single-point laser of the laser vibrometer is aligned with the diaphragm of the optical microphone under test.

[0046] Gradually increase the intensity of the acoustic emitter. When the optical microphone can detect the acoustic signal, read the reading of the laser vibrometer to obtain the test result of the minimum offset of the optical microphone.

[0047] Sixthly, the present invention provides a contact-type frequency response testing method for an optical microphone, implemented based on the aforementioned optical microphone testing system, comprising the following steps:

[0048] The optical microphone under test, the reference sensor, and the acoustic transmitter are pre-installed, with the reference sensor and the optical microphone under test symmetrically arranged about the vertical line where the acoustic transmitter is located as the axis of symmetry.

[0049] Drive the acoustic transmitter to emit acoustic signals of different frequencies;

[0050] The acquired signal of the optical microphone under test is analyzed, and the frequency response curve of the optical microphone under test is obtained by using the signal of the reference sensor as a reference.

[0051] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0052] The optical microphone testing platform and system provided by this invention offer both a non-contact testing platform and a contact testing platform. The non-contact testing platform includes a test bench, a three-dimensional support, a rotating platform, a lifting platform, a first microphone fixing device, and a reference sensor fixing device. The contact testing platform includes a test bracket, a test block, an optical microphone fixing bracket, and an acoustic transmitter fixing bracket. It can simultaneously perform non-contact and contact tests on the optical microphone under test. The non-contact tests include directivity tests, frequency response tests, and minimum offset tests, and it is convenient to replace the test object and perform repeated tests.

[0053] The optical microphone testing platform provided by the present invention includes a first microphone fixing device and a second microphone fixing device, which are respectively disposed on a non-contact testing platform and a contact testing platform. The first microphone fixing device and the second microphone fixing device are designed according to the shape characteristics of the optical microphone under test, and can be installed in a simple and convenient manner. Attached Figure Description

[0054] Figure 1 This is a schematic diagram of the structure of the non-contact testing platform provided in an embodiment of the present invention;

[0055] Figure 2 This is a schematic diagram of the structure of the rotating platform provided in an embodiment of the present invention;

[0056] Figure 3 This is a schematic diagram of the clamping state of the first microphone fixing device provided in an embodiment of the present invention;

[0057] Figure 4 This is a schematic diagram of the first microphone fixing device in the loosened state according to an embodiment of the present invention;

[0058] Figure 5 This is an internal schematic diagram of the first microphone fixing device provided in an embodiment of the present invention;

[0059] Figure 6 This is a schematic diagram of the lifting platform provided in an embodiment of the present invention;

[0060] Figure 7 This is a schematic diagram of the non-contact frequency response test principle provided in an embodiment of the present invention;

[0061] Figure 8 This is a schematic diagram of the structure of the contact testing platform provided in an embodiment of the present invention;

[0062] Figure 9 This is a schematic diagram of the second microphone fixing device provided in an embodiment of the present invention;

[0063] Figure 10 This is a top view of the acoustic emitter fixing device provided in an embodiment of the present invention;

[0064] Figure 11 This is a bottom view of the acoustic transmitter fixing device provided in an embodiment of the present invention;

[0065] Figure 12 This is a schematic diagram of the contact frequency response test provided in an embodiment of the present invention;

[0066] In the diagram: 1, test bench; 2, three-dimensional support; 2-1, x-axis support; 2-2, y-axis support; 2-3, z-axis support; 3, rotating platform; 4, first microphone fixing device; 4-1, movable clamping arm; 4-2, fixed clamping arm; 4-3, movable handle; 4-4, fixed handle; 4-5, gear; 5, reference sensor fixing device; 6, lifting platform; 7, test support; 8, test block; 9, second microphone fixing device; 9-1, first bolt; 9-2, optical microphone mounting head; 10, top horizontal support; 11, acoustic emitter fixing device; 11-1, acoustic emitter mounting head; 11-2, second bolt; 12, bottom horizontal support. Detailed Implementation

[0067] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0068] Example 1

[0069] This embodiment provides an optical microphone testing platform, including a non-contact testing platform and a contact testing platform. The non-contact testing platform is used to perform non-contact testing on the optical microphone under test, testing the detection effect when the sound source propagates in the air. The contact testing platform is used to perform contact testing on the optical microphone under test, testing the detection effect when the sound source propagates in a medium.

[0070] Figure 1 This is a schematic diagram of the non-contact testing platform provided in this embodiment, as shown below. Figure 1 As shown, the non-contact testing platform includes a test bench 1, a three-dimensional support 2, a rotating platform 3, a lifting platform 6, a first microphone fixing device 4, and a reference sensor fixing device 5;

[0071] The three-dimensional support 2 and the lifting platform 6 are installed on the table surface of the test bench 1;

[0072] The rotating platform 3 is mounted on the three-dimensional support 2. The first microphone fixing device 4 is mounted at the center of the rotating platform 3 for fixing the optical microphone under test. The reference sensor fixing device 5 is located on one side of the rotating platform 3 for fixing the reference sensor. In this embodiment, the reference sensor fixing device 5 has the same structure as the first microphone fixing device 4. The lifting platform 6 is used to mount the acoustic transmitter. The relative position between the optical microphone under test and the acoustic transmitter can be changed by adjusting the three-dimensional support 2, the rotating platform 3, and the lifting platform 6. The structure of the rotating platform 3 is as follows: Figure 2 As shown;

[0073] The three-dimensional support 2 includes two x-axis supports 2-1, a y-axis support 2-2, and a z-axis support 2-3;

[0074] The y-axis bracket 2-2 is fixed to the x-axis bracket 2-1 along an axial direction perpendicular to the x-axis bracket 2-1, and the y-axis bracket 2-2 can translate along the axial direction of the x-axis bracket 2-1.

[0075] The z-axis bracket 2-3 is fixed on the y-axis bracket 2-2 in an axial direction that is perpendicular to both the x-axis bracket 2-1 and the y-axis bracket 2-2, and the z-axis bracket 2-3 can translate along the axial direction of the y-axis bracket 2-2.

[0076] like Figure 5 As shown, the first microphone fixing device 4 includes a base, a movable clamping arm 4-1, a fixed clamping arm 4-2, a movable handle 4-3, a fixed handle 4-4, a gear 4-5, and a return spring;

[0077] The movable clamping arm 4-1 and the fixed clamping arm 4-2 are installed on one side of the base, and the movable handle 4-3 and the fixed handle 4-4 are installed on the other side of the base;

[0078] The root of the movable clamping arm 4-1 and the root of the movable handle 4-3 are respectively provided with meshing teeth. The meshing teeth of the movable clamping arm 4-1 and the meshing teeth of the movable handle 4-3 are parallel to each other and both mesh with the gear 4-5. Pressing the movable handle 4-3 can drive the gear 4-5 to rotate, thereby driving the movable clamping arm 4-1 to move in the opposite direction relative to the movable handle 4-3.

[0079] The return spring is mounted on gear 4-5. In its natural state, the return spring clamps the fixture formed by the movable clamping arm 4-1 and the fixed clamping arm 4-2. When the movable handle 4-3 is pressed, the fixture formed by the movable clamping arm 4-1 and the fixed clamping arm 4-2 opens. Figure 3 As shown; when the movable handle 4-3 is released, under the action of the return spring, the clamp formed by the movable clamping arm 4-1 and the fixed clamping arm 4-2 clamps tightly, as shown. Figure 4As shown, there is an arc-shaped opening in the middle for fixing the slender strip-shaped optical microphone under test.

[0080] like Figure 6 As shown, multiple lifting platforms 6 are also provided at the other end of the test bench 1 for installing various sound sources for multiple tests. The sound sources include single-frequency sound sources, broadband sound sources, and laser vibration meters. The height of the lifting platforms 6 is adjusted by a hand crank, and the lifting platforms 6 are equipped with fixing devices for fixing the sound sources.

[0081] When the relative positions of the optical microphone under test and the sound source need to be adjusted, the height of the sound source is adjusted by the lifting platform 6, and the position of the optical microphone under test in the xyz direction in space is adjusted by the three-dimensional bracket 2. In order to meet the directional test of the optical microphone, the rotating platform 3 can rotate at different angles in the horizontal plane.

[0082] like Figure 8 As shown, the contact test platform includes a test bracket 7, a test block 8, an optical microphone fixing bracket, and an acoustic emitter fixing bracket; wherein, the optical microphone fixing bracket is used to fix the optical microphone under test and the reference sensor, and the acoustic emitter fixing bracket is used to fix the acoustic emitter;

[0083] In this embodiment, the test block 8 is a cylindrical steel test block.

[0084] In contact testing, considering the replacement of the instrument under test, the acoustic emitter is fixed to the bottom of the contact testing platform, while the reference sensor and the optical microphone under test are fixed to the surface of the contact testing platform for testing. The test bracket 7 is used to support the test block 8. The acoustic emitter is fixed to the bottom of the test block 8 through the acoustic emitter fixing bracket, and the reference sensor and the optical microphone under test are fixed above the test block 8 through the optical microphone fixing bracket. The optical microphone fixing bracket is set parallel to the acoustic emitter fixing bracket.

[0085] The optical microphone mounting bracket includes a top horizontal bracket 10 and a second microphone mounting device 9. The second microphone mounting device 9 is installed in the middle of the top horizontal bracket 10 and is used to mount the optical microphone under test and the reference sensor.

[0086] like Figure 9 As shown, the second microphone fixing device 9 includes a first bolt 9-1 and an optical microphone mounting head 9-2; the optical microphone mounting head 9-2 is used to mount the optical microphone under test; the first bolt 9-1 is used to adjust the distance between the optical microphone under test and the test block 8.

[0087] The optical microphone mounting bracket also includes a bottom horizontal bracket 12 and an acoustic transmitter mounting device 11, the acoustic transmitter mounting device 11 being installed in the middle of the bottom horizontal bracket 12.

[0088] like Figure 10 , Figure 11 As shown, the acoustic emitter fixing device 11 includes an acoustic emitter mounting head 11-1 and a second bolt 11-2. The acoustic emitter mounting head 11-1 is used to install the acoustic emitter, and the second bolt 11-2 is used to adjust the distance between the acoustic emitter and the test block 8.

[0089] Example 2

[0090] This embodiment provides an optical microphone testing system, including the optical microphone testing platform provided in Embodiment 1, and further including: an acoustic transmitter, a reference sensor, a control motor, a testing host, and a host computer;

[0091] The acoustic transmitter and the reference sensor are both mounted on the optical microphone test platform;

[0092] The control motor is electrically connected to the three-dimensional support 2 and the rotating platform 3 respectively, and is used to control the movement of the three-dimensional support 2 and the rotating platform 3.

[0093] The test host is connected to the optical microphone under test and the reference sensor, and is used to collect the detection signals of the optical microphone under test and the reference sensor during testing.

[0094] The signal between the host computer and the test host is used to analyze the detection signal;

[0095] The test host is also connected to the control motor signal, and the control motor is controlled by the host computer through the test host.

[0096] The test host includes a signal acquisition device and a broadband amplifier; the signal acquisition device is used to acquire the detection signals of the optical microphone under test and the reference sensor during testing; the broadband amplifier is used to enhance the detection signals of the optical microphone under test and the reference sensor during testing.

[0097] Example 3

[0098] This embodiment provides a method for testing the directivity of an optical microphone, based on the optical microphone testing system described in Embodiment 2, and includes the following steps:

[0099] Adjust the three-dimensional support 2 and the lifting platform 6 to make the optical microphone under test and the single-frequency sound source coaxial. The single-frequency sound source emits the same sound signal. Adjust the angle of the rotating platform 3 and record the reading of the optical microphone under test at certain angle intervals to obtain the receiving performance of the optical microphone at different angles facing the sound source.

[0100] Example 4

[0101] This embodiment provides a non-contact frequency response testing method for an optical microphone, implemented based on the optical microphone testing system described in Embodiment 2, and includes the following steps:

[0102] Adjust the three-dimensional support 2 and the lifting platform 6, and adjust the relative positions of the broadband sound source, the reference sensor, and the optical microphone under test, so that the symmetrical central axis of the optical microphone under test and the reference sensor is coaxial with the center point of the broadband sound source, such as... Figure 7 As shown, a broadband sound source emits sound signals of different frequencies, and a signal acquisition device acquires the signals from the optical microphone under test and the reference sensor. The signal from the optical microphone under test is acquired by the signal acquisition device after being demodulated.

[0103] Place the reference sensor and optical microphone in the sound field, positioned symmetrically on both sides of the sound source axis. At this point, the detection signals on the optical microphone under test and the reference sensor are the same.

[0104] Adjust the sound source to a reference frequency within the calibration frequency range and output a sinusoidal signal of a certain voltage. After the sound source signal stabilizes, measure the sound pressure levels of the reference sensor and the optical microphone under test. and Calculate the acoustic signal sensitivity using the following formula. .

[0105]

[0106] In the formula,

[0107] The acoustic sensitivity value of the optical microphone, in dB;

[0108] Sound pressure level measurement of optical microphone, dB;

[0109] Reference sensor sound pressure level measurement, dB;

[0110] The acoustic sensitivity value of the reference sensor is in dB.

[0111] The acoustic sensitivity value at the required test frequency is measured using the above method, and the frequency response of the sensitivity is obtained.

[0112] Example 5

[0113] This embodiment provides a minimum offset test method for an optical microphone, implemented based on the optical microphone test system described in Embodiment 2, and includes the following steps:

[0114] Adjust the positions of the three-dimensional support 2 and the laser vibrometer so that the single-point laser of the laser vibrometer is aligned with the diaphragm of the optical microphone under test. Adjust the sound source intensity and read the laser vibrometer reading when the optical microphone can just detect the sound signal.

[0115] The optical microphone is placed in the sound field, and the laser beam of the laser vibrometer is aimed at the diaphragm of the optical microphone. The audio signal generator outputs a sinusoidal signal to drive the sound source to emit sound. The amplitude of the signal generator's output signal is adjusted so that the optical microphone can detect the sound signal. The amplitude of the signal generator's output signal is gradually reduced until the optical microphone can just detect the signal emitted by the sound source. Then, the laser vibrometer is used to measure the offset of the optical microphone diaphragm, which is the minimum measurable offset.

[0116] Example 6

[0117] This embodiment provides a contact frequency response testing method for an optical microphone, implemented based on the optical microphone testing system described in Embodiment 2, and includes the following steps:

[0118] Using test block 8 as the conductor, an acoustic emitter is installed at the center of one of the top and bottom surfaces of test block 8, and a reference sensor and the optical microphone under test are symmetrically installed on the other surface with the center as a reference. Figure 12 As shown, the acoustic transmitter is driven to emit signals of different frequencies, and the frequency response curve of the optical microphone under test is obtained by using a reference sensor as a reference.

[0119] A coupling agent is added between the sensor and the test block, and the static pressure between them should be no less than 9.8 N. The acoustic transmitter outputs a set of pulse signals with a pulse width of no less than 1 μs and an amplitude of no less than 5 V, and the frequency response of the tested optical microphone and the reference sensor is measured. , .

[0120] Sensitivity of the optical microphone under test Calculate according to the formula.

[0121]

[0122] In the formula:

[0123] The sensitivity of the optical microphone under test, in dB;

[0124] Reference sensor's calibration sensitivity, in dB;

[0125] The frequency response of the optical microphone under test is expressed in mV.

[0126] The frequency response of the reference sensor is expressed in mV.

[0127] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only used to explain the relative positional relationship and movement between components in a specific posture. If the specific posture changes, the directional indication will also change accordingly. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0128] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0129] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. An optical microphone testing platform, characterized in that: This includes both non-contact testing platforms and contact testing platforms; The non-contact testing platform includes a test bench (1), a three-dimensional support (2), a rotating platform (3), and a lifting platform (6). The three-dimensional support (2) and the lifting platform (6) are both installed on the test bench (1). The rotating platform (3) is installed on the three-dimensional support (2). The lifting platform (6) is used to install the acoustic transmitter. By adjusting the three-dimensional support (2), the rotating platform (3) and the lifting platform (6), the relative angle and relative position between the optical microphone under test and the acoustic transmitter can be changed. The non-contact testing platform also includes a first microphone fixing device (4), which is installed at the center of the rotating platform (3) and is used to fix the optical microphone under test. The first microphone fixing device (4) includes a base, a movable clamping arm (4-1), a fixed clamping arm (4-2), a movable handle (4-3), a fixed handle (4-4), a gear (4-5), and a return spring; The movable clamping arm (4-1) and the fixed clamping arm (4-2) are installed on one side of the base, and the movable handle (4-3) and the fixed handle (4-4) are installed on the other side of the base; The root of the movable clamping arm (4-1) and the root of the movable handle (4-3) are respectively provided with meshing teeth. The meshing teeth of the movable clamping arm (4-1) and the meshing teeth of the movable handle (4-3) are parallel to each other and both mesh with the gear (4-5). Pressing the movable handle (4-3) can drive the gear (4-5) to rotate, thereby driving the movable clamping arm (4-1) to move in the opposite direction relative to the movable handle (4-3). The reset spring is mounted on the gear (4-5). In its natural state, the reset spring clamps the fixture formed by the movable clamping arm (4-1) and the fixed clamping arm (4-2). The contact test platform includes a test bracket (7), a test block (8), an optical microphone fixing bracket, and an acoustic transmitter fixing bracket; The test block (8), the optical microphone mounting bracket and the acoustic transmitter mounting bracket are all installed on the test bracket (7), with the optical microphone mounting bracket located at the top of the test block (8) and the acoustic transmitter mounting bracket located at the bottom of the test block (8).

2. The optical microphone testing platform according to claim 1, characterized in that: The three-dimensional support (2) includes at least two x-axis supports (2-1), y-axis supports (2-2), and z-axis supports (2-3). The y-axis bracket (2-2) is fixed on the x-axis bracket (2-1) along the axial direction perpendicular to the x-axis bracket (2-1), and the y-axis bracket (2-2) can translate along the axial direction of the x-axis bracket (2-1). The z-axis bracket (2-3) is fixed on the y-axis bracket (2-2) in an axial direction that is perpendicular to both the x-axis bracket (2-1) and the y-axis bracket (2-2), and the z-axis bracket (2-3) can translate along the axial direction of the y-axis bracket (2-2).

3. The optical microphone testing platform according to claim 1, characterized in that: It also includes a reference sensor fixing device (5); The reference sensor fixing device (5) is located on one side of the rotating platform (3) and is used to fix the reference sensor.

4. The optical microphone testing platform according to claim 1, characterized in that: The optical microphone mounting bracket includes a top horizontal bracket (10) and a second microphone mounting device (9). The second microphone mounting device (9) is installed in the middle of the top horizontal bracket (10) and is used to mount the optical microphone under test and the reference sensor.

5. The optical microphone testing platform according to claim 4, characterized in that: The second microphone fixing device (9) includes a first bolt (9-1) and an optical microphone mounting head (9-2); The optical microphone mounting head (9-2) is used to mount the optical microphone under test; The first bolt (9-1) is used to adjust the distance between the optical microphone under test and the test block (8).

6. The optical microphone testing platform according to claim 1, characterized in that: The acoustic emitter mounting bracket includes a bottom horizontal bracket (12) and an acoustic emitter mounting device (11), which is installed in the middle of the bottom horizontal bracket (12).

7. The optical microphone testing platform according to claim 6, characterized in that: The acoustic emitter fixing device (11) includes an acoustic emitter mounting head (11-1) and a second bolt (11-2). The acoustic emitter mounting head (11-1) is used to install the acoustic emitter, and the second bolt (11-2) is used to adjust the distance between the acoustic emitter and the test block (8).

8. An optical microphone testing system, characterized in that: The optical microphone test platform as described in any one of claims 1-7 further includes an acoustic transmitter, a reference sensor, a control motor, a test host, and a host computer; The acoustic transmitter and the reference sensor are both mounted on the optical microphone test platform; The control motors are electrically connected to the three-dimensional support (2) and the rotating platform (3) respectively, and are used to control the movement of the three-dimensional support (2) and the rotating platform (3); The test host is connected to the optical microphone under test and the reference sensor, and is used to collect the detection signals of the optical microphone under test and the reference sensor during testing. The host computer is connected to the test host via a signal and is used to analyze the detection signal; The test host is also connected to the control motor signal, and the control motor is controlled by the host computer through the test host.

9. The optical microphone testing system according to claim 8, characterized in that: The test host includes signal acquisition equipment and a wideband amplifier; The signal acquisition device is used to acquire the detection signals of the optical microphone under test and the reference sensor during testing; The broadband amplifier is used to enhance the detection signal when the optical microphone under test and the reference sensor are tested.

10. A method for testing the directivity of an optical microphone, implemented based on the optical microphone testing system as described in any one of claims 8 or 9, characterized in that, Includes the following steps: The optical microphone and acoustic transmitter to be tested are pre-installed on the non-contact platform, wherein the acoustic transmitter is a single-frequency sound source. The three-dimensional support (2) and the lifting platform (6) are adjusted to make the optical microphone and acoustic transmitter to be tested coaxial. Drive the acoustic transmitter to emit an acoustic signal of the same frequency; Control the rotating platform (3) to rotate, and collect the signal of the optical microphone under test once every preset angle; The signals from a series of tested optical microphones were analyzed to obtain the directional test results of the optical microphones.

11. A non-contact frequency response testing method for an optical microphone, implemented based on the optical microphone testing system as described in any one of claims 8 or 9, characterized in that, Includes the following steps: The optical microphone under test, the reference sensor, and the acoustic transmitter are pre-installed on the non-contact platform, wherein the acoustic transmitter is a broadband sound source. The three-dimensional support (2) and the lifting platform (6) are adjusted so that the symmetrical central axis of the optical microphone under test and the reference sensor is coaxial with the center point of the acoustic transmitter. Drive the acoustic transmitter to emit acoustic signals of different frequencies; Acquire signals from the optical microphone under test and the reference sensor; The acquired signal of the optical microphone under test is analyzed, and the frequency response curve of the optical microphone under test is obtained by using the signal of the reference sensor as a reference.

12. A method for testing the minimum offset of an optical microphone, implemented based on the optical microphone testing system as described in any one of claims 8 or 9, characterized in that, Includes the following steps: The optical microphone and acoustic transmitter to be tested are pre-installed on the non-contact platform. The positions of the three-dimensional support (2) and the laser vibrometer are adjusted so that the single-point laser of the laser vibrometer is aligned with the diaphragm of the optical microphone to be tested. Gradually increase the intensity of the acoustic emitter. When the optical microphone can detect the acoustic signal, read the reading of the laser vibrometer to obtain the test result of the minimum offset of the optical microphone.

13. A contact-type frequency response test method for an optical microphone, implemented based on the optical microphone test system as described in any one of claims 8 or 9, characterized in that, Includes the following steps: The optical microphone under test, the reference sensor, and the acoustic transmitter are pre-installed on the contact platform. The reference sensor and the optical microphone under test are symmetrically arranged with the vertical line where the acoustic transmitter is located as the axis of symmetry. Drive the acoustic transmitter to emit acoustic signals of different frequencies; The acquired signal of the optical microphone under test is analyzed, and the frequency response curve of the optical microphone under test is obtained by using the signal of the reference sensor as a reference.

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