Device and method for calibrating dynamic response time of laser Doppler velocimeter

Abstract

The invention discloses a calibration device and method for the dynamic response time of a laser Doppler velocimeter, and belongs to the technical field of velocity measurement, and the calibration device is used in two stages of the calibration method, including the stage of the conduction time of an optical switch, and adopts a single-frequency laser, the optical switch, a photoelectric detector and an oscilloscope; and in the stage of simulating the conduction of the optical switch, the optical switch, the laser Doppler velocimeter and the echo simulation device are adopted. The calibration method comprises the following steps: measuring the conduction time of the light switch, and calibrating the rise time of a step signal during conduction; and simulating the standard signal, switching the optical switch from the off state to the on state, and calculating and determining the dynamic response time of the laser Doppler velocimeter. According to the invention, the speed step signal with fast speed change can be generated without constructing a physical standard speed source, and the speed step signal is used as a standard signal to calibrate the dynamic response time of the laser Doppler velocimeter, so that the dynamic speed measurement capability of the high-speed laser Doppler velocimeter is ensured.

Description

Technical Field

[0001] This application belongs to the field of velocity measurement technology, and in particular relates to a calibration device and method for the dynamic response time of a laser Doppler velocimeter. Background Technology

[0002] In high-speed measurement, laser Doppler velocimeters, with their excellent performance and good dynamic response capabilities, have been widely used in many industries in recent years, and their application in various fields is becoming increasingly widespread.

[0003] Currently, for the calibration of laser Doppler velocimeters, due to their speed measurement range of tens of kilometers per second, physical standard speed sources are insufficient to meet the calibration requirements. Echo simulation-based calibration methods are rapidly developing, capable of calibrating the speed measurement error of laser Doppler velocimeters. However, since laser Doppler velocimeters are primarily used in high-speed measurement scenarios, the speed of the measured object changes rapidly, sometimes by kilometers per second within microseconds. To ensure the accuracy of measuring rapidly changing speed signals, it is necessary to calibrate the dynamic response characteristics of the laser Doppler velocimeter. Currently, there is no mature method available for calibrating this characteristic of the velocimeter.

[0004] Therefore, it is necessary to design a calibration device and calibration method for calibrating the dynamic response time of laser Doppler velocimeters to solve the calibration problem of the dynamic response time of laser Doppler velocimeters and ensure the accuracy of the dynamic response indicators of such devices. Summary of the Invention

[0005] This application aims to solve the technical problem of dynamic response time calibration of laser Doppler velocimeters. To this end, this application provides a calibration device and method for the dynamic response time of laser Doppler velocimeters. It can generate a rapidly changing velocity step signal without constructing a physical standard velocity source, and use it as a standard signal to calibrate the dynamic response time of the laser Doppler velocimeter, thus ensuring the dynamic velocity measurement capability of the high-speed laser Doppler velocimeter.

[0006] In a first aspect, embodiments of this application provide a calibration device for the dynamic response time of a laser Doppler velocimeter, comprising:

[0007] A single-frequency laser is used to generate a laser beam.

[0008] A photodetector, used to convert signals from a laser beam;

[0009] An oscilloscope is used to measure the signal output by a photodetector.

[0010] Optical switches are used for signal on / off control.

[0011] An echo simulation device is used to simulate the signal of a single-frequency laser and transmit the signal to a laser Doppler velocimeter.

[0012] Specifically, during the conduction time of the optical switch, the single-frequency laser is communicatively connected to the input end of the optical switch, the photodetector is communicatively connected to the output end of the optical switch, and the oscilloscope is electrically connected to the photodetector; during the conduction time of the simulated optical switch, the echo simulation device is communicatively connected to the optical switch, and the optical switch is communicatively connected to the laser Doppler velocimeter.

[0013] In some implementations, the oscilloscope displays the rise time of the signal output by the photodetector during the on-time of the photometer switch.

[0014] In some implementations, the echo simulation device simulates a velocity step signal that is consistent with the rise time by means of optical frequency modulation and / or wavelength adjustment.

[0015] In some implementations, when the optical switch is turned off, it is open at a first level and turned on at a second level. The first level is lower than the second level, and the time for the optical switch to switch from the first level to the second level is the rise time.

[0016] In some implementations, the communication connection is made using fiber optic cables during the conduction time of the photodetector switch or during the conduction time of the analog optical switch.

[0017] In some implementations, optical switches include acousto-optic switches and electro-optic switches.

[0018] Secondly, embodiments of this application provide a calibration method for the dynamic response time of a laser Doppler velocimeter, which employs the calibration device for the dynamic response time of a laser Doppler velocimeter as described above. The calibration method includes:

[0019] The conduction time of the photometer switch is determined, and the rise time of the step signal during conduction is calibrated.

[0020] The simulation can generate a standard signal with the same rise time as the step signal, switch the optical switch from the off state to the on state, and calculate and determine the dynamic response time of the laser Doppler velocimeter.

[0021] Thirdly, embodiments of this application provide a calibration method for the dynamic response time of a laser Doppler velocimeter, which employs the calibration device for the dynamic response time of a laser Doppler velocimeter as described above. The calibration method includes:

[0022] Connect the single-frequency laser, optical switch, photodetector, and oscilloscope;

[0023] Turn on the single-frequency laser, switch the optical switch from the off state to the on state, and measure the rise time of the step signal displayed on the oscilloscope.

[0024] Connect the echo simulation device, optical switch, and laser Doppler velocimeter;

[0025] Turn on the laser Doppler velocimeter, set the parameters of the echo simulation device, turn on the echo simulation device and the optical switch, and simulate a step signal when the optical switch switches from the off state to the on state. The signal simulated by the echo simulation device is used as the standard signal.

[0026] Analyze the velocity change curve of the standard signal received by the laser Doppler velocimeter, calculate the rise time in the velocity change curve, and obtain the dynamic response time of the laser Doppler velocimeter.

[0027] In some implementations, when a single-frequency laser, an optical switch, a photodetector, and an oscilloscope are connected, the laser beam emitted by the single-frequency laser can pass through the optical switch, the photodetector, and the oscilloscope in sequence.

[0028] In some implementations, when the echo simulation device, the optical switch, and the laser Doppler velocimeter are connected, the signal simulated by the echo simulation device can pass through the optical switch and the laser Doppler velocimeter in sequence.

[0029] As can be seen from the above technical solution, the beneficial effects of this application are as follows:

[0030] 1. The calibration device of this application, in the case of the difficulty in constructing a physical standard velocity source, innovatively proposes a velocity step signal based on the optical switch on / off method for calibrating laser Doppler velocimeters. This signal is then simulated using echo simulation, thereby achieving error calibration of the laser Doppler velocimeter. Specifically, this application generates a laser beam using a single-frequency laser. The signal passes through an optical switch and is then input to a photodetector. The optical signal is converted into an electrical signal, and the waveform is displayed on an oscilloscope. The rise time when the optical switch is turned on can be determined from the waveform. An echo simulation device can then simulate a signal with the same rise time. This simulated signal is then input to the laser Doppler velocimeter after passing through the optical switch, thereby measuring the dynamic response time of the Doppler velocimeter. This application can generate a rapidly changing velocity step signal without constructing a physical standard velocity source, and use this signal as a standard signal to calibrate the dynamic response time of the laser Doppler velocimeter, ensuring the dynamic velocity measurement capability of the high-speed laser Doppler velocimeter.

[0031] 2. The calibration method of this application calibrates the conduction time of the optical switch by switching it on and off, then simulates and constructs a standard signal capable of generating the calibration signal, and then uses the velocity change caused by the conduction of the optical switch to determine the dynamic response time of the laser Doppler velocimeter. This application does not require the construction of a physical standard velocity source. An optical signal is generated by a single-frequency laser, and then the signal changes are displayed on the oscilloscope using a photodetector and an oscilloscope. By switching the optical switch on and off, a rapidly changing velocity step signal can be generated. The step signal is simulated by an echo simulation device and used as a standard signal. Thus, by measuring the signal velocity change of the laser Doppler velocimeter, the dynamic response time of the laser Doppler velocimeter is calibrated while ensuring accuracy. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced one by one below. Obviously, the accompanying drawings described below are some embodiments of this application. For those skilled in the art, other embodiments and drawings can be obtained based on these drawings without creative effort. Various schematic diagrams according to the embodiments of this application are shown in the accompanying drawings. These drawings are not necessarily drawn to scale. For the purpose of clarity, some details have been enlarged and some details may have been omitted.

[0033] Figure 1 A schematic diagram of an embodiment of the calibration device for the dynamic response time of a laser Doppler velocimeter according to the present invention is shown in the on-time of the photometer switch;

[0034] Figure 2 A schematic diagram of an embodiment of the calibration device for the dynamic response time of a laser Doppler velocimeter according to the present invention is shown in connection with the conduction time of an analog optical switch;

[0035] Figure 3 The diagram shows a step signal appearing on an oscilloscope when the optical switch is in the on state, using the calibration device for the dynamic response time of a laser Doppler velocimeter according to the present invention.

[0036] Figure 4 The diagram shows the humidity variation curve of the step signal of the laser Doppler velocimeter in the calibration device for the dynamic response time of the laser Doppler velocimeter according to the present invention.

[0037] Figure 5 A schematic flowchart of an embodiment of the calibration method of the present invention for the dynamic response time of a laser Doppler velocimeter is shown. Detailed Implementation

[0038] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. The detailed description of the embodiments of this application provided in the drawings is not intended to limit the scope of the claimed application. The described embodiments are only a part of the embodiments of this application, not all of them. Based on the embodiments in this application, they can be arranged and designed in various different configurations. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0039] This application is described below with reference to the accompanying drawings and specific embodiments:

[0040] Please refer to Figure 1 and Figure 2 According to a first aspect of this application, a calibration device for the dynamic response time of a laser Doppler velocimeter is provided. This device includes a single-frequency laser, a photodetector, an oscilloscope, an optical switch, and an echo simulation device. The calibration device is used in two stages of the calibration method: a stage for measuring the conduction time of the optical switch and a stage for simulating the conduction of the optical switch. Both stages use TTL level control to switch the optical switch on and off. The stage for measuring the conduction time of the optical switch employs: a single-frequency laser, typically a conventional single-longitudinal-mode laser, for generating a laser beam; a photodetector, a conventional photoelectric conversion device, for converting signals from the laser beam; an oscilloscope, such as a digital oscilloscope, capable of displaying the waveform corresponding to the signal, for measuring the signal output by the photodetector; and an optical switch, which employs existing optical path dynamic control devices for signal on / off control, such as an acousto-optic switch or an electro-optic switch. The conduction stage of the simulated optical switch employs: an optical switch, a laser Doppler velocimeter, and an echo simulation device. The optical switch is the aforementioned device, and the laser Doppler velocimeter is existing equipment. The echo simulation device is used to simulate the signal of a single-frequency laser and transmit the signal to the laser Doppler velocimeter. The echo simulation device can be the device used for simulating echo signal light in patent CN120161219A, or it can be a simulation device that can autonomously generate simulated signals according to parameters.

[0041] In this process, when measuring the conduction time of the optical switch, the single-frequency laser is communicatively connected to the input of the optical switch, and the photodetector is communicatively connected to the output of the optical switch. These communication connections are made via fiber optic cables. The oscilloscope is electrically connected to the photodetector via an RF cable. Taking an acousto-optic switch as an example, the optical propagation path is as follows: the beam emitted from the single-frequency laser enters the acousto-optic switch through the fiber optic cable. When the acousto-optic switch closes, the beam signal passes through the acousto-optic switch and then through the fiber optic cable to the photodetector. The photodetector converts the optical signal into an electrical signal, which is then connected to the oscilloscope via the RF cable for signal display. The oscilloscope can directly measure the rise time of the signal change at the instant the acousto-optic switch closes, thereby calibrating the acousto-optic switch conduction time.

[0042] When the simulated optical switch is turned on, the echo simulation device communicates with the optical switch, and the optical switch communicates with the laser Doppler velocimeter. Similarly, the communication connection uses fiber optic cables. The echo simulation device constructs a continuous simulated velocity signal, which is connected to the input end of the optical switch via fiber optic cables. After the optical switch is turned on, it generates a rapidly changing optical signal, which is connected to the laser Doppler velocimeter via fiber optic cables at the output end. The laser Doppler velocimeter provides a velocity change curve, and its velocity rise time is the dynamic response time of the laser Doppler velocimeter. The dynamic response time of the laser Doppler velocimeter should be greater than or equal to the on-time of the aforementioned acousto-optic switch.

[0043] Current technology lacks a suitable calibration device for measuring the dynamic response time of laser Doppler velocimeters. This is because laser Doppler velocimeters are primarily used in high-speed measurement scenarios. During actual use, the speed of the measured object changes rapidly, sometimes by kilometers per second within a few microseconds. Furthermore, in high-speed measurement, speed is not a fundamental physical quantity but rather a derived quantity. In China, there is no "standard" speed source; speed values ​​are generated through other methods. Therefore, ensuring accuracy in calibrating the dynamic response characteristics presents significant challenges.

[0044] This application's calibration device, addressing the challenge of constructing a physical standard velocity source for laser Doppler velocimeters, innovatively proposes a velocity step signal generation method based on optical switch on / off switching. This is followed by echo simulation to simulate the velocity, thereby achieving error calibration of the laser Doppler velocimeter. Specifically, this application generates a laser beam using a single-frequency laser. The signal passes through an optical switch and is then input to a photodetector. The optical signal is converted into an electrical signal, which is then displayed on an oscilloscope. The rise time when the optical switch is turned on can be determined from the waveform. An echo simulation device can then simulate a signal with the same rise time. This simulated signal is passed through the optical switch and input to the laser Doppler velocimeter to measure its dynamic response time. This application eliminates the need to construct a physical standard velocity source to generate a rapidly changing velocity step signal, which serves as a standard signal for calibrating the dynamic response time of the laser Doppler velocimeter, ensuring the dynamic velocity measurement capability of high-speed laser Doppler velocimeters. By combining existing calibration devices for laser Doppler velocimeters, the metrology system of laser Doppler velocimeters can be further improved.

[0045] In some implementations, the oscilloscope displays the rise time of the signal output by the photodetector when measuring the on-time of the optical switch. The optical switch, through its switching effect, enables the light beam to conduct rapidly, thereby generating a rapidly changing velocity step signal; the velocity change time is the on-time of the optical switch.

[0046] In some implementations, the echo simulation device simulates a velocity step signal with a rise time consistent with the optical frequency modulation and / or wavelength adjustment. The echo simulation device generates a simulated echo signal to construct the reference velocity signal required for calibration.

[0047] In some implementations, when the optical switch is open, it is open at a first voltage level and open at a second voltage level. The first voltage level is lower than the second voltage level, and the time it takes for the optical switch to switch from the first voltage level to the second voltage level is the rise time. The first voltage level is low, and the second voltage level is high. When the optical switch is open, the oscilloscope signal displays a low voltage level; when the optical switch is open, the oscilloscope signal displays a high voltage level. The rise time required for the signal to transition from low to high voltage is the on-time of the optical switch.

[0048] In some implementations, the communication connection is made using fiber optic cables during the conduction time of the photodetector switch or when the analog photodetector switch is on. Fiber optic cables are the optimal material for this solution, but other cables for communication connections, such as optical-electric composite cables, can also be used.

[0049] In some implementations, optical switches include acousto-optic switches and electro-optic switches. Acousto-optic switches are based on the acousto-optic effect, and electro-optic switches are based on the electro-optic effect. Both are devices used in optical systems to control the switching of optical paths.

[0050] A second aspect of this application provides a calibration method for the dynamic response time of a laser Doppler velocimeter, which employs the calibration device for the dynamic response time of a laser Doppler velocimeter as described above. The calibration method includes:

[0051] 1. The conduction time of the photometer switch, and the rise time of the step signal during conduction are calibrated; when the conduction time of the photometer switch is measured, according to... Figure 1 The diagram shows the connection of a single-frequency laser, an optical switch, a photodetector, and an oscilloscope; the waveform changes of the signal displayed on the oscilloscope before and after the optical switch is turned on are shown below. Figure 3 As shown, a sudden change can be clearly seen in the waveform.

[0052] 2. Simulate a standard signal that generates a rise time consistent with the step signal, switch the optical switch from the off state to the on state, and calculate the dynamic response time of the laser Doppler velocimeter; when simulating the optical switch being on, according to... Figure 2 Connect the echo simulation device, optical switch, and laser Doppler velocimeter; the wave velocity change of the signal measured by the Doppler velocimeter is as follows: Figure 4 As shown in the figure, the dynamic response time of the Doppler velocimeter is determined based on the time interval Δt corresponding to the rise of the waveform in the figure.

[0053] A third aspect of this application provides a calibration method for the dynamic response time of a laser Doppler velocimeter, which employs the calibration device for the dynamic response time of a laser Doppler velocimeter as described above. The calibration method includes:

[0054] S1. Arrange the single-frequency laser, optical switch, photodetector, and oscilloscope according to... Figure 1 The connection is shown.

[0055] S2. Turn on the single-frequency laser to preheat the equipment, switch the optical switch from the off state to the on state, and a step signal will appear on the oscilloscope. Measure the rise time of the step signal displayed on the oscilloscope; this time is the on-time t0 of the acousto-optic switch.

[0056] S3. Connect the echo simulation device, optical switch and laser Doppler velocimeter. Specifically, first disconnect the device in step S1, then reconnect the three devices to build a device to simulate the conduction of the optical switch. You can first turn on the laser Doppler velocimeter and echo simulation device to preheat the equipment.

[0057] S4. Turn on the laser Doppler velocimeter, set the parameters of the echo simulation device, turn on the echo simulation device and the optical switch, and set appropriate parameters. The optical switch must be switched from the off state to the on state to simulate a step signal. The signal simulated by the echo simulation device is used as the standard signal.

[0058] S5. The above standard signal is received by the Doppler velocimeter, which then provides the velocity change curve of the step signal, such as... Figure 4 As shown, the velocity change curve of the standard signal received by the laser Doppler velocimeter is analyzed, and the rise time in the velocity change curve is calculated, which is the dynamic response time t of the laser Doppler velocimeter (t>t0).

[0059] In some implementations, when a single-frequency laser, an optical switch, a photodetector, and an oscilloscope are connected: the laser beam emitted by the single-frequency laser passes sequentially through the optical switch, the photodetector, and the oscilloscope. The laser beam emitted from the single-frequency laser is connected to the input end of the optical switch via an optical fiber, and the output end of the optical switch is connected to the photodetector via an optical fiber. The photodetector converts the optical signal into an electrical signal, which is then connected to the oscilloscope via an radio frequency cable.

[0060] In some implementations, when the echo simulation device, optical switch, and laser Doppler velocimeter are connected: the signal simulated by the echo simulation device can pass sequentially through the optical switch and the laser Doppler velocimeter. The simulated signal from the echo simulation device is input to the input terminal of the optical switch. When the optical switch changes from an open to an on state, it generates a velocity step signal with a known rise time. This signal is used as a standard signal and input to the laser Doppler velocimeter.

[0061] Existing technologies lack a reliable calibration method for measuring the dynamic response time of laser Doppler velocimeters. The calibration methods described in the second and third aspects above calibrate the conduction time of an optical switch by switching it on and off, then simulate a standard signal capable of generating a calibration signal, and finally use the velocity change caused by the optical switch's conduction to determine the dynamic response time of the laser Doppler velocimeter. This application eliminates the need to construct a physical standard velocity source. Instead, it generates an optical signal using a single-frequency laser, and then displays the signal changes on the oscilloscope using a photodetector and an oscilloscope. By switching the optical switch on and off, a rapidly changing velocity step signal can be generated. This step signal is simulated using an echo simulation device and used as a standard signal. Thus, by measuring the signal velocity change of the laser Doppler velocimeter, the dynamic response time of the laser Doppler velocimeter can be calibrated accurately.

[0062] Please refer to Figure 5 The following describes the calibration process for a 1550nm laser Doppler velocimeter, using a calibration device built according to the present invention.

[0063] (1) According to Figure 1 Connect the instruments as shown, set up the device for calibrating the conduction time of the acousto-optic switch, turn on the single-frequency laser, set the output wavelength of the single-frequency laser to 1550nm, and preheat the equipment.

[0064] (2) The laser beam is connected to the input end of the optical switch via an optical fiber wire, and the output end of the optical switch is connected to the photodetector via an optical fiber wire.

[0065] (3) The photodetector converts the optical signal into an electrical signal, which is then connected to the oscilloscope via an RF cable;

[0066] (4) When the sound and light switch changes from open to on, a step signal appears on the oscilloscope, such as... Figure 3 As shown, the rise time of the step signal is the conduction time of the acousto-optic switch, and the conduction time of the acousto-optic switch is t0 = 11.39 ns.

[0067] (5) Based on Figure 2 Complete the instrument connection, set up the dynamic response time calibration device for the laser Doppler velocimeter, and turn on the laser Doppler velocimeter and echo simulation calibration device to preheat the equipment.

[0068] (6) The echo simulation device uses optical frequency modulation to modulate the emitted light of the velocimeter. The modulation frequency is 2.4381 GHz, and the corresponding simulated speed signal is v = 1.89 km / s. The echo simulation signal is connected to the input terminal of the acousto-optic switch. When the acousto-optic switch changes from open to closed, it will generate a speed step signal of 0 to 1.89 km / s with a rise time of 11.39 ns. This signal is used as a standard signal to be connected to the laser Doppler velocimeter for the dynamic response time calibration of the velocimeter.

[0069] (7) The velocity step signal is received by the laser Doppler velocimeter, which provides the velocity change curve of the step as shown in the figure. Figure 4 As shown, by analyzing the rise time of the velocity curve, the dynamic response time of the laser Doppler velocimeter is found to be t = 89.6 ns.

[0070] Regarding the specific implementation methods of this application, it should be noted that:

[0071] In the description of this application, unless otherwise expressly specified and limited, the terms "connection," "fixed," "connected," etc., should be interpreted broadly. For example, "fixed" can refer to a fixed connection, a detachable connection, or an integral molding; "connection" can refer to a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can refer to the internal connection of two components or the interaction between two components, unless otherwise expressly limited; "connected" can refer to the internal connection of two parts and the connection between two parts, or the spatial connection between them, whereby the two parts are directly or indirectly connected through the part forming the space. The terms "set," "installed," "equipped with," "configured," etc., should also be interpreted broadly. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0072] In the description of this application, the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the system or component 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 this application. All directional indications are only used to explain the relative positional relationship and movement between components in a specific orientation. If the specific orientation changes, the directional indication will also change accordingly.

[0073] In the description of this application, the use of terms such as "some embodiments," "optional embodiments," "example," "specific example," "optional example," or "optional embodiment," etc., indicates that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application, but does not imply that these embodiments illustrate and describe all possible forms of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Furthermore, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0074] The present invention has been described in detail above with reference to specific embodiments and exemplary examples. The above description is exemplary and not exhaustive, and is not limited to the disclosed embodiments; the above description should not be construed as a limitation of the present invention. Technical solutions between various embodiments can be combined with each other, but must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed in this application. Although embodiments of the present application have been shown and described, various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present application. Those skilled in the art will understand that various other specific changes and combinations of embodiments based on the technical teachings disclosed in this application, without departing from the essence of the present application, are still within the scope of protection defined by the claims of the present invention and their equivalent technical solutions.

Claims

1. A calibration device for the dynamic response time of a laser Doppler velocimeter, characterized in that, include: A single-frequency laser is used to generate a laser beam; A photodetector is used to convert signals from the laser beam; An oscilloscope is used to measure the signal output by the photodetector; Optical switches are used for signal on / off control; An echo simulation device is used to simulate the signal of the single-frequency laser and transmit the signal to a laser Doppler velocimeter. Specifically, when measuring the conduction time of the optical switch, the single-frequency laser is communicatively connected to the input terminal of the optical switch, the photodetector is communicatively connected to the output terminal of the optical switch, and the oscilloscope is electrically connected to the photodetector; when simulating the conduction of the optical switch, the echo simulation device is communicatively connected to the optical switch, and the optical switch is communicatively connected to the laser Doppler velocimeter.

2. The calibration device for the dynamic response time of a laser Doppler velocimeter according to claim 1, characterized in that, When measuring the conduction time of the optical switch, the oscilloscope displays the rise time of the signal output by the photodetector.

3. The calibration device for the dynamic response time of a laser Doppler velocimeter according to claim 2, characterized in that, The echo simulation device simulates a velocity step signal that is consistent with the rise time through optical frequency modulation and / or wavelength adjustment.

4. The calibration device for the dynamic response time of a laser Doppler velocimeter according to claim 2, characterized in that, When the optical switch is turned off, the optical switch is turned off at a first level and turned on at a second level. The first level is lower than the second level, and the time for the optical switch to switch from the first level to the second level is the rise time.

5. The calibration device for the dynamic response time of a laser Doppler velocimeter according to claim 1, characterized in that, When measuring the conduction time of the optical switch or simulating the conduction of the optical switch, the communication connection is made using an optical fiber cable.

6. The calibration device for the dynamic response time of a laser Doppler velocimeter according to claim 1, characterized in that, The optical switch includes an acoustic-optical switch and an electro-optical switch.

7. A calibration method for the dynamic response time of a laser Doppler velocimeter, characterized in that, The calibration method employs the calibration device for the dynamic response time of a laser Doppler velocimeter as described in any one of claims 1-6, wherein the calibration method includes: The conduction time of the optical switch is measured, and the rise time of the step signal during conduction is calibrated. The simulation generates a standard signal with the same rise time as the step signal, switches the optical switch from the off state to the on state, and calculates and determines the dynamic response time of the laser Doppler velocimeter.

8. A calibration method for the dynamic response time of a laser Doppler velocimeter, characterized in that, The calibration method employs the calibration device for the dynamic response time of a laser Doppler velocimeter as described in any one of claims 1-6, wherein the calibration method includes: Connect the single-frequency laser, the optical switch, the photodetector, and the oscilloscope; Turn on the single-frequency laser, switch the optical switch from the off state to the on state, and measure the rise time of the step signal displayed on the oscilloscope. Connect the echo simulation device, the optical switch, and the laser Doppler velocimeter; Turn on the laser Doppler velocimeter, set the parameters of the echo simulation device, turn on the echo simulation device and the optical switch, and simulate the step signal when the optical switch switches from the off state to the on state. The signal simulated by the echo simulation device is used as the standard signal. Analyze the velocity change curve of the standard signal received by the laser Doppler velocimeter, calculate the rise time in the velocity change curve, and obtain the dynamic response time of the laser Doppler velocimeter.

9. The calibration method for the dynamic response time of a laser Doppler velocimeter according to claim 8, characterized in that, When the single-frequency laser, the optical switch, the photodetector, and the oscilloscope are connected: the laser beam emitted by the single-frequency laser can pass through the optical switch, the photodetector, and the oscilloscope in sequence.

10. The calibration method for the dynamic response time of a laser Doppler velocimeter according to claim 8, characterized in that, When the echo simulation device, the optical switch, and the laser Doppler velocimeter are connected: the signal simulated by the echo simulation device can pass through the optical switch and the laser Doppler velocimeter in sequence.

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