A terahertz liquid level measurement system and method

Abstract

The present application relates to the technical field of liquid level measurement, and aims to provide a terahertz liquid level measurement system and method, the system comprising: a terahertz transmitting device for transmitting a terahertz spherical beam signal; a signal conversion device for collimating the terahertz spherical beam signal into a terahertz plane beam signal, and making the terahertz plane beam signal incident to a liquid to be measured to obtain a terahertz plane wave echo signal, and focusing the terahertz plane wave echo signal into a terahertz spherical beam echo signal; a first signal turning device for changing the transmission direction of the terahertz spherical beam echo signal; a terahertz receiving device for receiving and processing the terahertz spherical beam echo signal to obtain an intermediate frequency signal; and a data processing device connected with the terahertz receiving device, the data acquisition device being used for receiving and processing the intermediate frequency signal to obtain liquid level data. The precision of liquid level measurement is improved.

Description

Technical Field

[0001] This invention relates to the field of liquid level measurement technology, and specifically to a terahertz liquid level measurement system and method. Background Technology

[0002] In industrial production, scientific research, and environmental monitoring, it is often necessary to accurately measure parameters such as the liquid level and volume in various containers, tanks, pipes, or other liquid storage devices to determine whether subsequent work can proceed normally.

[0003] Existing liquid level measurement methods can be broadly categorized into contact and non-contact methods. Contact methods require direct contact with the liquid being measured, which can easily cause contamination and makes them unsuitable for certain scenarios. Non-contact methods mainly include laser measurement, acoustic measurement, and microwave radar measurement. Laser and acoustic methods are susceptible to environmental temperature and pressure fluctuations and cannot penetrate non-metallic containers. Microwave radar measurement methods have low ranging accuracy and are sensitive to the dielectric constant of the liquid, thus limiting their applicability. Summary of the Invention

[0004] The purpose of this invention is to provide a terahertz liquid level measurement system and method, and the technical problem to be solved is to improve the accuracy of liquid level measurement.

[0005] This invention is achieved through the following technical solution:

[0006] The first aspect provides a terahertz liquid level measurement system, comprising:

[0007] Terahertz transmitting equipment is used to transmit terahertz spherical beam signals;

[0008] A signal conversion device is used to be placed on the transmission path of a terahertz spherical beam signal to collimate the terahertz spherical beam signal into a terahertz plane beam signal, and to incident the terahertz plane beam signal onto the liquid to be tested to obtain a terahertz plane wave echo signal, and to focus the terahertz plane wave echo signal into a terahertz spherical beam echo signal.

[0009] The first signal steering device is used to be set on the transmission path of the terahertz spherical beam echo signal to change the transmission direction of the terahertz spherical beam echo signal.

[0010] A terahertz receiving device is used to be positioned on the transmission path of the terahertz spherical beam echo signal after the transmission direction has been changed, to receive the terahertz spherical beam echo signal, and to process the terahertz spherical beam echo signal to obtain an intermediate frequency signal.

[0011] The data processing equipment is connected to the terahertz receiving equipment. The aforementioned data acquisition equipment is used to receive and process intermediate frequency signals to obtain liquid level data.

[0012] Because terahertz beams have a high frequency, their measurement resolution and accuracy are relatively high. Through signal conversion equipment and a first signal steering device, the terahertz spherical beam signal can be collimated into a terahertz planar beam signal, increasing the terahertz beam energy density. Simultaneously, it ensures that the terahertz beam is incident parallel to the liquid surface being measured, reducing power loss and system size during transmission to some extent, thus compensating for the low transmission power of terahertz systems. Furthermore, focusing and steering the echo signal improves measurement accuracy.

[0013] Because of its high frequency, the terahertz beam has strong anti-interference capabilities. During liquid level measurement, there may be some interfering factors, such as fluctuations in the liquid surface and reflections from the container wall. However, due to the high-frequency characteristics of the terahertz beam, it can effectively avoid the influence of these interfering factors, thereby improving the stability of the liquid level measurement and further enhancing its accuracy.

[0014] This system can measure liquid levels in real time. The connections and data processing methods between the terahertz transmitter, signal converter, first signal redirector, terahertz receiver, and data processing equipment enable the system to quickly receive, process, and output liquid level data. Therefore, this system is suitable for applications requiring real-time monitoring of liquid level changes; because terahertz beams have good penetration through many substances, it can be used to measure liquids of different types and concentrations. Furthermore, its applicability can be further expanded by adjusting system parameters and processing methods.

[0015] Terahertz beams are harmless to humans and the environment, thus this liquid level measurement system has high safety and reliability. In industrial production processes, liquid level measurement is one of the most important parameters. Using this system for liquid level measurement can avoid the safety hazards and environmental pollution caused by traditional measurement methods.

[0016] In summary, this terahertz liquid level measurement system has significant advantages and promising application prospects in improving the accuracy of liquid level measurement.

[0017] Furthermore, it also includes a second signal steering device, which is set on the transmission path of the terahertz spherical beam signal to change the transmission direction of the terahertz spherical beam signal;

[0018] The aforementioned signal conversion device is used to be installed on the transmission path after the second signal steering device changes the transmission direction of the terahertz spherical beam signal.

[0019] By adding a second signal redirection device to the aforementioned terahertz level measurement system, the terahertz spherical beam signal can be redirected twice, further improving signal transmission efficiency and measurement accuracy. Specifically, the first redirection involves changing the transmission direction of the terahertz spherical beam signal using the second signal redirection device. This step aims to guide the signal to the signal conversion device for subsequent conversion processing. The second redirection occurs in the signal conversion device, where the terahertz spherical beam signal is collimated into a terahertz plane beam signal and incident on the liquid being measured, resulting in a terahertz plane wave echo signal. This step aims to enable the signal to propagate in a more stable and focused manner, reducing the influence of interference factors and thus improving measurement accuracy.

[0020] Furthermore, by connecting the second signal steering device and the signal conversion device, the entire system structure can be made more compact and efficient; at the same time, by reasonably adjusting the connection relationship and parameter settings between the devices, the measurement performance and applicability of the system can be further optimized.

[0021] Furthermore, the aforementioned first signal steering device is disposed between the second signal steering device and the signal conversion device;

[0022] The aforementioned first signal steering device is also used to transmit the terahertz spherical beam signal after changing the transmission direction, split the terahertz spherical beam signal into two, obtain a first terahertz spherical beam signal and a second terahertz spherical beam signal, transmit the first terahertz spherical beam signal to the signal conversion device, and transmit the second terahertz spherical beam signal to the terahertz receiving device.

[0023] In the aforementioned terahertz level measurement system, a first signal redirection device is positioned between the second signal redirection device and the signal conversion device. This design further optimizes the signal transmission path and processing. First, the first signal redirection device transmits the terahertz spherical beam signal after its transmission direction has been changed, splitting it into a first terahertz spherical beam signal and a second terahertz spherical beam signal. This design allows one part of the signal to be directly transmitted to the signal conversion device for processing, while the other part is transmitted to the terahertz receiving device for reception and further processing. By dividing the signal into two parts, the system's stability and reliability are increased. Firstly, one part of the signal is used to directly measure the liquid level, while the other part is used to calibrate and verify the accuracy of the measurement results. This design effectively reduces the impact of signal interference, fluctuations, and other factors on the measurement results, thereby improving measurement accuracy.

[0024] Furthermore, by placing the first signal redirection device between the second signal redirection device and the signal conversion device, the connection relationships and signal transmission paths between the devices can be further optimized, making the entire system more efficient and compact. At the same time, this design allows for flexible expansion and adjustment of the system according to actual application needs, to meet the measurement requirements of different occasions.

[0025] In summary, incorporating a first signal deflection device into the terahertz level measurement system can further improve the system's stability and measurement accuracy, while also enhancing its flexibility and applicability.

[0026] Furthermore, the aforementioned data processing equipment includes a data acquisition card and a host computer;

[0027] The input terminal of the aforementioned data acquisition card is connected to the output terminal of the terahertz receiving device to receive and process intermediate frequency signals;

[0028] The output terminal of the aforementioned data acquisition card is connected to the input terminal of the host computer. The host computer is used to receive and process the intermediate frequency signal transmitted by the data acquisition card, and to obtain and display the liquid level data.

[0029] The aforementioned data acquisition card can receive and process intermediate frequency (IF) signals in real time. Data acquisition cards typically have high sampling rates and processing capabilities, enabling rapid and accurate acquisition and processing of IF signals. The aforementioned host computer is a high-performance computer device used for data acquisition, processing, and display. By connecting the data acquisition card and the host computer, the processed IF signal can be transmitted to the host computer for further processing and display. The host computer can analyze, calculate, and visualize the data, thus providing an intuitive and real-time display of liquid level data.

[0030] By integrating the data acquisition card and host computer into the terahertz liquid level measurement system, real-time data acquisition, processing, and display can be achieved, making the liquid level measurement results more accurate, reliable, and intuitive. Furthermore, this design allows for remote monitoring and control via the host computer, making the measurement process more flexible and convenient.

[0031] In summary, the terahertz liquid level measurement system with the addition of a data acquisition card and a host computer has more complete and efficient functions in data processing and display, further improving the system's measurement accuracy and application value.

[0032] Furthermore, the aforementioned data acquisition card includes an intermediate frequency filter, an intermediate frequency amplifier, and an analog-to-digital converter connected in sequence.

[0033] By adding an intermediate frequency (IF) filter, an IF amplifier, and an analog-to-digital converter (ADC) to the data acquisition card, the data processing and conversion process can be further optimized. The IF filter is used to remove noise and interference from the IF signal, thereby extracting effective liquid level information. Since various noises and interferences may affect liquid level measurement, the IF filter can effectively suppress these interferences and improve the accuracy of the measurement. The IF amplifier amplifies the IF signal to facilitate subsequent analog-to-digital conversion and processing. Because the amplitude of the IF signal may be small, making accurate digitization difficult, the IF amplifier amplifies the signal to improve the sensitivity and accuracy of the measurement. The ADC converts the analog IF signal into a digital signal for computer processing and storage. By converting analog signals to digital signals, fast and accurate processing and storage of liquid level data can be achieved.

[0034] By adding an intermediate frequency filter, an intermediate frequency amplifier, and an analog-to-digital converter to the data acquisition card, the data processing and conversion process of the terahertz liquid level measurement system can be further optimized, improving the system's measurement accuracy and stability. This design also allows for flexible adjustment and optimization of each component according to actual application requirements to meet the measurement requirements of different occasions.

[0035] Furthermore, the transmitting end of the aforementioned terahertz transmitting device is equipped with an amplifier, which is used to amplify the transmitted terahertz spherical beam signal.

[0036] The transmitted terahertz spherical beam signal is amplified by an amplifier, further improving signal strength and transmission distance. Because terahertz beam signals have high frequency and low energy, amplification increases signal strength and stability, thus reducing interference and noise during liquid level measurement. By placing the amplifier at the transmitting end of the terahertz transmitting device, direct amplification of the transmitted signal can be achieved, thereby improving signal strength and transmission efficiency. Furthermore, this design allows for flexible adjustment and optimization of amplifier parameters according to actual application requirements, meeting the measurement requirements of different situations.

[0037] The second aspect provides a terahertz liquid level measurement method, which uses the above-mentioned terahertz liquid level measurement system;

[0038] The method includes the following steps:

[0039] S1. Place the liquid to be tested directly below the signal conversion device;

[0040] S2. The terahertz transmitting device transmits a terahertz spherical beam signal, which is transmitted to a signal conversion device, which collimates the terahertz spherical beam signal into a terahertz planar beam signal.

[0041] S3. The above-mentioned signal conversion device transmits the terahertz plane beam signal to the surface of the liquid to be tested and receives the feedback terahertz plane beam echo signal.

[0042] S4. The above-mentioned signal conversion device focuses the received terahertz plane beam echo signal into a terahertz spherical beam echo signal, and transmits the terahertz spherical beam echo signal to the first signal turning device.

[0043] S5. The aforementioned first signal steering device changes the transmission direction of the terahertz spherical beam echo signal and transmits the terahertz spherical beam echo signal after the transmission direction has been changed to the terahertz receiving device.

[0044] S6. The above-mentioned terahertz receiving device receives the terahertz spherical beam echo signal, processes the terahertz spherical beam echo signal to obtain an intermediate frequency signal, and transmits the intermediate frequency signal to the data processing device.

[0045] S7. The above-mentioned data acquisition equipment receives and processes the intermediate frequency signal to obtain liquid level data.

[0046] Furthermore, S2 also includes the following steps:

[0047] S21. The aforementioned terahertz transmitting device transmits a terahertz spherical beam signal, which is transmitted to the second signal steering device.

[0048] S22. The second signal steering device changes the transmission direction of the terahertz spherical beam signal and transmits the terahertz spherical beam signal with the changed transmission direction to the first signal steering device.

[0049] S23. The aforementioned first signal steering device splits the terahertz spherical beam signal into two, obtaining a first terahertz spherical beam signal and a second terahertz spherical beam signal. The first terahertz spherical beam signal is transmitted to the signal conversion device, and the second terahertz spherical beam signal is transmitted to the terahertz receiving device.

[0050] Furthermore, the specific steps in S6 to process the terahertz spherical beam echo signal to obtain the intermediate frequency signal include:

[0051] S61. The second terahertz spherical beam signal is subjected to frequency doubling to obtain the local oscillator signal;

[0052] S62. Mix the above terahertz spherical beam echo signal and local oscillator signal to obtain the intermediate frequency signal.

[0053] Furthermore, the specific steps in S7 for processing intermediate frequency signals to obtain liquid level data include:

[0054] S71. Record the intermediate frequency signal received by the data processing equipment;

[0055] S72. Use the Hilbert transform to convert the real signal of the intermediate frequency signal into a complex signal, and perform an N-point fast Fourier transform on the complex signal to obtain the peak frequency.

[0056] S73. Divide the complex signal into two segments to obtain two subsequences. Perform linear frequency modulation Z-transform on the two subsequences at their peak frequencies respectively.

[0057] S74. Extract the peak phases of the two subsequences after linear frequency modulation Z-transformation, and calculate the phase difference between the peak phases of the two subsequences;

[0058] S75. Perform phase expansion on the above phase difference to obtain a new phase difference;

[0059] S76, Utilization Calculate the liquid level data;

[0060] in, This represents liquid level data; c represents the speed of light. The new phase difference is represented by N; the number of points in the intermediate frequency signal is represented by B; the bandwidth of the terahertz system is represented by B; and N1 represents the number of points in each sub-sequence after segmentation of the complex signal.

[0061] This terahertz liquid level measurement method achieves efficient processing and analysis of intermediate frequency signals, yielding accurate liquid level data. Furthermore, by employing advanced signal processing methods such as Hilbert transform and fast Fourier transform, the method also possesses high measurement accuracy and anti-interference capabilities. By processing the echo signal using signal frequency and phase information and a high-precision liquid level measurement algorithm, micrometer-level ranging accuracy can be achieved.

[0062] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0063] Because terahertz beams have a high frequency, their measurement resolution and accuracy are relatively high. Through signal conversion equipment and a first signal steering device, the terahertz spherical beam signal can be collimated into a terahertz planar beam signal, increasing the terahertz beam energy density. Simultaneously, it ensures that the terahertz beam is incident parallel to the liquid surface being measured, reducing power loss and system size during transmission to some extent, thus compensating for the low transmission power of terahertz systems. Furthermore, focusing and steering the echo signal improves measurement accuracy.

[0064] Because of its high frequency, the terahertz beam has strong anti-interference capabilities. During liquid level measurement, there may be some interfering factors, such as fluctuations in the liquid surface and reflections from the container wall. However, due to the high-frequency characteristics of the terahertz beam, it can effectively avoid the influence of these interfering factors, thereby improving the stability of the liquid level measurement and further enhancing its accuracy.

[0065] Because terahertz beams have good penetrability to many substances, they can be used to measure liquids of different types and concentrations. Furthermore, their applicability can be expanded by adjusting system parameters and processing methods. Attached Figure Description

[0066] To more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. In the drawings:

[0067] Figure 1 This is a schematic diagram showing the location arrangement of each device in a terahertz liquid level measurement system.

[0068] Figure 2 A schematic diagram of the hardware structure for generating terahertz signals;

[0069] Figure 3 This is a flowchart of a terahertz liquid level measurement method.

[0070] The attached diagram shows the markings and corresponding component names:

[0071] 1. Second signal switching device; 2. First signal switching device; 3. Signal conversion device; 4. Terahertz transmitting device; 5. Terahertz receiving device; 6. Data acquisition device; 7. Host computer; 8. Baseband source; 9. First amplifier; 10. 1-to-2 power divider; 11. Transmitter frequency doubling link; 12. Second amplifier; 13. Terahertz transmitting antenna; 14. Quasi-optical system; 15. Liquid under test; 16. Terahertz receiving antenna; 17. Mixer; 18. Local oscillator frequency doubling link; 19. Intermediate frequency filter; 20. Intermediate frequency amplifier; 21. ADC; 22. PC. Detailed Implementation

[0072] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0073] Example 1

[0074] This embodiment 1 provides a terahertz liquid level measurement system, including:

[0075] Terahertz transmitting device 4 (which can use a 110-170GHz terahertz transmitting link or a horn antenna) is used to transmit terahertz spherical beam signals;

[0076] Signal conversion device 3 (which may be a parabolic mirror) is used to be placed on the transmission path of the terahertz spherical beam signal to collimate the terahertz spherical beam signal into a terahertz plane beam signal, and to incident the terahertz plane beam signal onto the liquid to be measured 15 to obtain a terahertz plane wave echo signal carrying liquid level information, and to focus the terahertz plane wave echo signal into a terahertz spherical beam echo signal.

[0077] The first signal steering device 2 (which may be a beam splitter) is used to be placed on the transmission path of the terahertz spherical beam echo signal to change the transmission direction of the terahertz spherical beam echo signal.

[0078] Terahertz receiving device 5 (which can be a 110-170GHz terahertz receiving link) is used to be set on the terahertz spherical beam echo signal transmission path after the transmission direction is changed, to receive the terahertz spherical beam echo signal, and to process the terahertz spherical beam echo signal to obtain an intermediate frequency signal.

[0079] The data processing device is connected to the terahertz receiving device 5. The aforementioned data acquisition device 6 is used to receive and process intermediate frequency signals to obtain liquid level data.

[0080] Because terahertz beams have a high frequency, their measurement resolution and accuracy are relatively high. Through signal conversion device 3 and first signal steering device 2, the terahertz spherical beam signal can be collimated into a terahertz planar beam signal, increasing the energy density of the terahertz beam. At the same time, it ensures that the terahertz beam is incident parallel to the liquid surface under test, which to some extent reduces the power loss and system size of the terahertz beam during transmission and compensates for the low transmission power of the terahertz system. Furthermore, the echo signal is focused and steering, improving the measurement accuracy.

[0081] Because of its high frequency, the terahertz beam has strong anti-interference capabilities. During liquid level measurement, there may be some interfering factors, such as fluctuations in the liquid surface and reflections from the container wall. However, due to the high-frequency characteristics of the terahertz beam, it can effectively avoid the influence of these interfering factors, thereby improving the stability of the liquid level measurement and further enhancing its accuracy.

[0082] This system can measure liquid level in real time. The connections and data processing methods between the terahertz transmitter 4, signal conversion device 3, first signal redirection device 2, terahertz receiver 5, and data processing device enable the system to quickly receive, process, and output liquid level data. Therefore, this system is suitable for applications requiring real-time monitoring of liquid level changes; because terahertz beams have good penetration through many substances, it can be used to measure liquids of different types and concentrations. Furthermore, its applicability can be further expanded by adjusting system parameters and processing methods.

[0083] Terahertz beams are harmless to humans and the environment, thus this liquid level measurement system has high safety and reliability. In industrial production processes, liquid level measurement is one of the most important parameters. Using this system for liquid level measurement can avoid the safety hazards and environmental pollution caused by traditional measurement methods.

[0084] In summary, this terahertz liquid level measurement system has significant advantages and promising application prospects in improving the accuracy of liquid level measurement.

[0085] Example 2

[0086] Combination Figure 1 Based on Embodiment 1, it also includes a second signal steering device 1 (which may be a reflector), which is set on the transmission path of the terahertz spherical beam signal to change the transmission direction of the terahertz spherical beam signal.

[0087] The aforementioned signal conversion device 3 is used to be installed on the transmission path after the second signal steering device 1 changes the transmission direction of the terahertz spherical beam signal.

[0088] By adding a second signal redirection device 1 to the aforementioned terahertz liquid level measurement system, the terahertz spherical beam signal can be redirected twice, further improving signal transmission efficiency and measurement accuracy. Specifically, the first redirection involves changing the transmission direction of the terahertz spherical beam signal through the second signal redirection device 1. This step aims to guide the signal to the signal conversion device 3 for subsequent conversion processing. The second redirection occurs in the signal conversion device 3, where the terahertz spherical beam signal is collimated into a terahertz plane beam signal and incident on the liquid to be measured 15, resulting in a terahertz plane wave echo signal. This step aims to enable the signal to propagate in a more stable and focused manner and reduce the influence of interference factors, thereby improving measurement accuracy.

[0089] Furthermore, by connecting the second signal steering device 1 and the signal conversion device 3, the structure of the entire system can be made more compact and efficient; at the same time, by reasonably adjusting the connection relationship and parameter settings between the devices, the measurement performance and applicability of the system can be further optimized.

[0090] In a specific embodiment, the first signal steering device 2 is disposed between the second signal steering device 1 and the signal conversion device 3;

[0091] The aforementioned first signal steering device 2 is also used to transmit the terahertz spherical beam signal after changing the transmission direction, split the terahertz spherical beam signal into two, obtain a first terahertz spherical beam signal and a second terahertz spherical beam signal, transmit the first terahertz spherical beam signal to the signal conversion device 3, and transmit the second terahertz spherical beam signal to the terahertz receiving device 5.

[0092] In the aforementioned terahertz liquid level measurement system, the first signal redirection device 2 is positioned between the second signal redirection device 1 and the signal conversion device 3. This design further optimizes the signal transmission path and processing. Firstly, the first signal redirection device 2 transmits the terahertz spherical beam signal after its transmission direction has been changed, splitting it into a first terahertz spherical beam signal and a second terahertz spherical beam signal. This design allows one part of the signal to be directly transmitted to the signal conversion device 3 for processing, while the other part is transmitted to the terahertz receiving device 5 for reception and further processing. By dividing the signal into two parts, the stability and reliability of the system can be increased. Firstly, one part of the signal is used to directly measure the liquid level, while the other part is used to calibrate and verify the accuracy of the measurement results. This design effectively reduces the impact of signal interference, fluctuations, and other factors on the measurement results, thereby improving measurement accuracy.

[0093] Furthermore, by placing the first signal redirection device 2 between the second signal redirection device 1 and the signal conversion device 3, the connection relationships and signal transmission paths between the devices can be further optimized, making the entire system more efficient and compact. At the same time, this design allows for flexible expansion and adjustment of the system according to actual application needs, to meet the measurement requirements of different occasions.

[0094] In summary, the design of adding a first signal steering device 2 to the terahertz liquid level measurement system can further improve the system's stability and measurement accuracy, while also enhancing the system's flexibility and applicability.

[0095] In a specific embodiment, the data processing device mentioned above includes a data acquisition card and a host computer 7;

[0096] The input terminal of the aforementioned data acquisition card is connected to the output terminal of the terahertz receiving device 5, and is used to receive and process intermediate frequency signals;

[0097] The output terminal of the aforementioned data acquisition card is connected to the input terminal of the host computer 7. The host computer 7 is used to receive and process the intermediate frequency signal transmitted by the data acquisition card, and to obtain and display the liquid level data.

[0098] The aforementioned data acquisition card can receive and process intermediate frequency (IF) signals in real time. Data acquisition cards typically have high sampling rates and processing capabilities, enabling rapid and accurate acquisition and processing of IF signals. The aforementioned host computer 7 is a high-performance computer device used for data acquisition, processing, and display. By connecting the data acquisition card and host computer 7, the processed IF signal can be transmitted to host computer 7 for further processing and display. Host computer 7 can analyze, calculate, and visualize the data, thereby providing an intuitive and real-time display of liquid level data.

[0099] By integrating the data acquisition card and the host computer 7 into the terahertz liquid level measurement system, real-time data acquisition, processing, and display can be achieved, making the liquid level measurement results more accurate, reliable, and intuitive. Furthermore, this design allows for remote monitoring and control via the host computer 7, making the measurement process more flexible and convenient.

[0100] In summary, the terahertz liquid level measurement system with the addition of the data acquisition card and host computer 7 has more complete and efficient functions in data processing and display, further improving the system's measurement accuracy and application value.

[0101] In a specific embodiment, the data acquisition card includes an intermediate frequency filter 19, an intermediate frequency amplifier 20, and an analog-to-digital converter connected in sequence.

[0102] By adding an intermediate frequency (IF) filter 19, an IF amplifier 20, and an analog-to-digital converter (ADC) to the data acquisition card, the data processing and conversion process can be further optimized. The IF filter 19 is used to filter out noise and interference in the IF signal, thereby extracting effective liquid level information. Since various noises and interferences may affect the liquid level measurement process, the IF filter 19 can effectively suppress these interferences and improve the accuracy of the liquid level measurement. The IF amplifier 20 is used to amplify the IF signal to facilitate subsequent analog-to-digital conversion and processing. Because the amplitude of the IF signal may be small, making accurate digitization difficult, the IF amplifier 20 amplifies the signal to improve the sensitivity and accuracy of the measurement. The ADC is used to convert the analog IF signal into a digital signal for computer processing and storage. By converting the analog signal into a digital signal, fast and accurate processing and storage of liquid level data can be achieved.

[0103] By adding an intermediate frequency filter 19, an intermediate frequency amplifier 20, and an analog-to-digital converter to the data acquisition card, the data processing and conversion process of the terahertz liquid level measurement system can be further optimized, improving the system's measurement accuracy and stability. This design also allows for flexible adjustment and optimization of each component according to actual application requirements to meet measurement requirements in different situations.

[0104] In a specific embodiment, the transmitting end of the terahertz transmitting device 4 is equipped with an amplifier, which is used to amplify the transmitted terahertz spherical beam signal.

[0105] The transmitted terahertz spherical beam signal is amplified by an amplifier, further improving signal strength and transmission distance. Because terahertz beam signals have high frequency and low energy, amplification increases signal strength and stability, thereby reducing interference and noise during liquid level measurement. By placing the amplifier at the transmitting end of the terahertz transmitting device 4, direct amplification of the transmitted signal can be achieved, thus improving signal strength and transmission efficiency. Furthermore, this design allows for flexible adjustment and optimization of amplifier parameters according to actual application requirements, meeting the measurement requirements of different situations.

[0106] The specific working principle is as follows: The 110-170GHz terahertz transmitting link transmits a terahertz spherical beam signal, which is reflected by a reflector to a beam splitter, transmitted to a parabolic mirror and collimated into a plane wave that is incident on the liquid surface of the container under test. The reflected beam carrying the liquid level information is reflected back to the parabolic mirror and focused into a spherical beam, which is then reflected by the beam splitter and received by the 110-170GHz terahertz receiving link. After being acquired by the data acquisition card, the intermediate frequency signal can be obtained. After being processed by the upper computer's algorithm, the liquid level information can be displayed in real time.

[0107] Combination Figure 2 The specific hardware structure for generating terahertz signals is as follows: It includes a base frequency source 8, a first amplifier 9, a 1-to-2 power divider 10, a transmit frequency multiplier link 11, a second amplifier 12, a terahertz transmitting antenna 13, a quasi-optical system 14, a terahertz receiving antenna 16, a mixer 17, a local oscillator frequency multiplier link 18, an intermediate frequency filter 19, an intermediate frequency amplifier 20, an ADC 21, and a PC 22. The base frequency source 8 generates a linear frequency modulated continuous wave signal, which is amplified by the first amplifier 9 and then split into two signals by the 1-to-2 power divider 10. One signal is multiplied by 1 by the transmit frequency multiplier link 11. A 10-170 GHz terahertz signal is amplified and radiated by a transmitting antenna to produce a terahertz spherical beam. This beam is collimated into a planar beam by a collimating system 14 and incident on the surface of the liquid to be measured 15. The reflected beam carrying liquid level information is reflected back to the collimating system 14 and focused into a spherical beam, which is then received by a receiving antenna. The echo signal is mixed in a mixer 17 with another signal that has been multiplied by a local oscillator link 18 to become an intermediate frequency (IF) signal. The IF signal is filtered by an IF filter 19 and amplified by an IF amplifier 20. It is then acquired by an ADC 21 and displayed on a PC 22.

[0108] Example 3

[0109] This embodiment 3 provides a terahertz liquid level measurement method, which uses the above-mentioned terahertz liquid level measurement system;

[0110] The method includes the following steps:

[0111] S1. Place the liquid to be tested directly below the signal conversion device;

[0112] S2. The terahertz transmitting device transmits a terahertz spherical beam signal, which is transmitted to a signal conversion device, which collimates the terahertz spherical beam signal into a terahertz planar beam signal.

[0113] S3. The above-mentioned signal conversion device transmits the terahertz plane beam signal to the surface of the liquid to be tested and receives the feedback terahertz plane beam echo signal.

[0114] S4. The above-mentioned signal conversion device focuses the received terahertz plane beam echo signal into a terahertz spherical beam echo signal, and transmits the terahertz spherical beam echo signal to the first signal turning device.

[0115] S5. The aforementioned first signal steering device changes the transmission direction of the terahertz spherical beam echo signal and transmits the terahertz spherical beam echo signal after the transmission direction has been changed to the terahertz receiving device.

[0116] S6. The above-mentioned terahertz receiving device receives the terahertz spherical beam echo signal, processes the terahertz spherical beam echo signal to obtain an intermediate frequency signal, and transmits the intermediate frequency signal to the data processing device.

[0117] S7. The above-mentioned data acquisition equipment receives and processes the intermediate frequency signal to obtain liquid level data.

[0118] Furthermore, S2 also includes the following steps:

[0119] S21. The aforementioned terahertz transmitting device transmits a terahertz spherical beam signal, which is transmitted to the second signal steering device.

[0120] S22. The second signal steering device changes the transmission direction of the terahertz spherical beam signal and transmits the terahertz spherical beam signal with the changed transmission direction to the first signal steering device.

[0121] S23. The aforementioned first signal steering device splits the terahertz spherical beam signal into two, obtaining a first terahertz spherical beam signal and a second terahertz spherical beam signal. The first terahertz spherical beam signal is transmitted to the signal conversion device, and the second terahertz spherical beam signal is transmitted to the terahertz receiving device.

[0122] Furthermore, the specific steps in S6 to process the terahertz spherical beam echo signal to obtain the intermediate frequency signal include:

[0123] S61. The second terahertz spherical beam signal is subjected to frequency doubling to obtain the local oscillator signal;

[0124] S62. Mix the above terahertz spherical beam echo signal and local oscillator signal to obtain the intermediate frequency signal.

[0125] Furthermore, in combination Figure 3 The specific steps for processing intermediate frequency signals and obtaining liquid level data in S7 include:

[0126] S71, Record the intermediate frequency signal received by the data processing device. ;

[0127] S72. Use the Hilbert transform to convert the real signal of the intermediate frequency signal into a complex signal. The peak frequency f is obtained by performing an N-point Fast Fourier Transform on the complex signal.

[0128] S73. Divide the complex signal into two segments to obtain two subsequences. The first N1 sequences are denoted as... The last N1 sequences are denoted as The two subsequences are refined by performing linear frequency modulation Z-transform at the peak frequency;

[0129] S74. Extract the peak phases of the two sub-sequences after linear frequency modulation Z-transformation, and denot them as follows: and and utilize Calculate the phase difference between the peak phases of the two subsequences;

[0130] S75, Regarding the above phase difference Perform phase unrolling to obtain a new phase difference. ;

[0131] S76, Utilization Calculate the liquid level data;

[0132] in, This represents liquid level data; c represents the speed of light. The new phase difference is represented by N; the number of points in the intermediate frequency signal is represented by B; the bandwidth of the terahertz system is represented by B; and N1 represents the number of points in each sub-sequence after segmentation of the complex signal.

[0133] This terahertz liquid level measurement method achieves efficient processing and analysis of intermediate frequency signals, yielding accurate liquid level data. Furthermore, by employing advanced signal processing methods such as Hilbert transform and fast Fourier transform, the method also possesses high measurement accuracy and anti-interference capabilities. By processing the echo signal using signal frequency and phase information and a high-precision liquid level measurement algorithm, micrometer-level ranging accuracy can be achieved.

[0134] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A terahertz liquid level measurement system, characterized in that, include: Terahertz transmitting equipment (4), used to transmit terahertz spherical beam signals; The signal conversion device (3) is used to be set on the transmission path of the terahertz spherical beam signal, to collimate the terahertz spherical beam signal into the terahertz plane beam signal, and to incident the terahertz plane beam signal onto the liquid to be tested (15) to obtain the terahertz plane wave echo signal, and to focus the terahertz plane wave echo signal into the terahertz spherical beam echo signal. The first signal steering device (2) is used to be set on the transmission path of the terahertz spherical beam echo signal to change the transmission direction of the terahertz spherical beam echo signal. Terahertz receiving device (5) is used to be set on the terahertz spherical beam echo signal transmission path after the transmission direction is changed, to receive the terahertz spherical beam echo signal, and to process the terahertz spherical beam echo signal to obtain an intermediate frequency signal. The data acquisition device (6) is connected to the terahertz receiving device (5). The data acquisition device is used to receive and process intermediate frequency signals to obtain liquid level data. The terahertz liquid level measurement system also includes a second signal steering device (1), which is set on the transmission path of the terahertz spherical beam signal to change the transmission direction of the terahertz spherical beam signal. The signal conversion device (3) is used to be installed on the transmission path after the second signal steering device (1) changes the transmission direction of the terahertz spherical beam signal; The first signal steering device (2) is disposed between the second signal steering device (1) and the signal conversion device (3); The first signal steering device (2) is also used to transmit the terahertz spherical beam signal after changing the transmission direction, split the terahertz spherical beam signal into two, and obtain the first terahertz spherical beam signal and the second terahertz spherical beam signal. The first terahertz spherical beam signal is transmitted to the signal conversion device (3), and the second terahertz spherical beam signal is transmitted to the terahertz receiving device (5). in The specific steps to obtain the intermediate frequency signal include: The second terahertz spherical beam signal is subjected to frequency doubling to obtain the local oscillator signal; The terahertz spherical beam echo signal and the local oscillator signal are mixed to obtain the intermediate frequency signal; The specific steps to obtain liquid level data include: Record the intermediate frequency signal received by the data processing equipment; The real signal of the intermediate frequency signal is converted into a complex signal using the Hilbert transform, and the peak frequency is obtained by performing an N-point fast Fourier transform on the complex signal. The complex signal is divided into two segments to obtain two subsequences, and the two subsequences are subjected to linear frequency modulation Z-transform at the peak frequency respectively. Extract the peak phases of the two subsequences after linear frequency modulation Z-transformation, and calculate the phase difference between the peak phases of the two subsequences; The phase difference is expanded to obtain a new phase difference; use Calculate the liquid level data; in, This represents liquid level data; c represents the speed of light. The new phase difference is represented by N; the number of points in the intermediate frequency signal is represented by B; the bandwidth of the terahertz system is represented by B; and N1 represents the number of points in each sub-sequence after segmentation of the complex signal.

2. The terahertz liquid level measurement system according to claim 1, characterized in that, The data processing equipment includes a data acquisition card and a host computer (7); The input terminal of the data acquisition card is connected to the output terminal of the terahertz receiving device (5) for receiving and processing intermediate frequency signals; The output end of the data acquisition card is connected to the input end of the host computer (7). The host computer (7) is used to receive and process the intermediate frequency signal transmitted by the data acquisition card, and to obtain and display the liquid level data.

3. The terahertz liquid level measurement system according to claim 2, characterized in that, The data acquisition card includes an intermediate frequency filter (19), an intermediate frequency amplifier (20), and an analog-to-digital converter connected in sequence.

4. The terahertz liquid level measurement system according to claim 1, characterized in that, The terahertz transmitting device (4) is equipped with an amplifier at its transmitting end, which is used to amplify the transmitted terahertz spherical beam signal.

5. A terahertz liquid level measurement method, characterized in that, This method employs the terahertz liquid level measurement system as described in any one of claims 1 to 4; The method includes the following steps: S1. Place the liquid to be tested directly below the signal conversion device; S2. The terahertz transmitting device transmits a terahertz spherical beam signal, which is transmitted to a signal conversion device, which collimates the terahertz spherical beam signal into a terahertz planar beam signal. S3. The signal conversion device transmits the terahertz plane beam signal to the surface of the liquid to be tested and receives the terahertz plane beam echo signal fed back. S4. The signal conversion device focuses the received terahertz plane beam echo signal into a terahertz spherical beam echo signal and transmits the terahertz spherical beam echo signal to the first signal steering device. S5. The first signal steering device changes the transmission direction of the terahertz spherical beam echo signal and transmits the terahertz spherical beam echo signal after the transmission direction has been changed to the terahertz receiving device. S6. The terahertz receiving device receives the terahertz spherical beam echo signal, processes the terahertz spherical beam echo signal to obtain an intermediate frequency signal, and transmits the intermediate frequency signal to the data processing device. S7. The data acquisition device receives and processes the intermediate frequency signal to obtain liquid level data.

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