Ultra-large dynamic range pulse field strength test system and method

Abstract

The invention provides a super-large dynamic range pulse field strength test system and method, comprising a pulse signal receiving front end, a first-level weak signal detection link, a second-level medium-intensity signal detection link, a third-level high-intensity signal detection link and a signal field strength magnitude calculation module; the pulse signal receiving front end is an ultra-wideband horn antenna, which is used to receive an unknown pulse signal to be tested; the first-level weak signal detection link is used to perform a field strength test on a pulse signal with a weak signal strength; the second-level medium-intensity signal detection link is used to perform a field strength test on a pulse signal with a large signal strength; the third-level high-intensity signal detection link is used to perform a field strength test on a strong pulse signal; the signal field strength magnitude calculation module is used to perform high-precision measurement and calibration on the field strength magnitude of the pulse signal; the system can realize hierarchical measurement of pulse signals of unknown power levels within a super-large dynamic range, and has the characteristics of large test dynamic range, high stability and high test precision.

Description

Technical Field

[0001] The invention belongs to the application field of microwave measurement and relates to a super-large dynamic range pulse field strength testing system and method. Background Art

[0002] Electronic warfare is a struggle between the enemy and the enemy for the control and use of electromagnetic spectrum resources on the battlefield. It has become another important battlefield after the traditional three-dimensional warfare of sea, land and air, and is the key to the victory or defeat of modern warfare. The modern electronic battlefield has both low-power pulse weak signals such as early warning radar, communication, electronic reconnaissance and noise interference, and high-power pulse strong interference signals emitted by microwave directed energy weapons. The electromagnetic environment is extremely complex. Accurately measuring the electric field strength of such complex signals at the same time is a prerequisite for improving electronic warfare capabilities.

[0003] At present, the field strength test of strong pulse signals mainly includes frequency domain method, time domain method and broadband field strength meter method. The frequency domain method uses a spectrum analyzer and a receiving antenna for measurement, which can obtain the amplitude-frequency characteristics of the signal in a wide frequency band. However, when parameters such as pulse width and pulse period are unknown, the pulse signal spectrum may not be accurately obtained due to improper setting of the resolution bandwidth (RBW). The time domain method uses an oscilloscope and a receiving antenna for measurement, which can obtain parameters such as the pulse width and pulse period of the signal. The spectrum characteristics of the pulse signal can be obtained by Fourier transforming the time domain measurement results. However, according to the Nyquist sampling theorem, in order to obtain correct measurement results for the time domain method, the sampling rate of the oscilloscope should be greater than twice the highest frequency component of the measured signal. The broadband field strength meter method uses an electric field probe and a field strength meter for measurement. It has a large measurement dynamic range and is convenient and flexible to use without correction. However, for pulse fields, the average field strength is obtained and frequency information cannot be provided. In view of the advantages and disadvantages of time and frequency domain measurement methods, some scholars have proposed a combined time and frequency domain measurement method for radar pulse fields. When the parameters of the transmitting source are unknown, a combined time and frequency domain measurement is performed once, and the frequency domain measurement results of the frequency domain method due to improper RBW setting are corrected using the time domain measurement information. This can obtain an accurate peak field strength of the pulse field. However, this method needs to consider parameters such as antenna coefficient and cable attenuation. The measurement result processing and analysis are complex. For high-power pulse field measurements, the spectrum analyzer and oscilloscope need to be shielded and connected to an attenuator to avoid burning. In addition, this method uses a receiving antenna with large size and aperture. For near-field distribution, due to large field fluctuations, it is impossible to accurately reflect the field distribution of each measurement point of the receiving antenna.

[0004] As for weak pulse signals, the difficulty of detection is greater than that of pulse signals. Here, weak signals do not only mean that the amplitude of the signal is very small compared to noise, but mainly refer to signals that are submerged by noise and have a very low signal-to-noise ratio. There are five classic basic methods for detecting them: (1) filtering method; (2) sampling integration and digital averaging method; (3) correlation detection method; (4) adaptive noise cancellation method; (5) photon counter method. Most of the basic ideas are to improve the signal-to-noise ratio through technical means, so as to achieve weak signal extraction. In recent years, some new methods for weak signal detection have been proposed, among which the following methods are of great significance: (1) weak signal detection method based on chaotic oscillators; (2) weak signal detection method based on stochastic resonance theory; (3) weak signal detection method based on wavelet transform; (4) weak signal detection method based on sparse decomposition; (5) weak signal detection method based on deep learning model. These new methods detect weak signals from a new perspective on the characteristics of weak signals.

[0005] In summary, the field strength measurement of strong pulse signals or weak pulse signals can be carried out according to the classical test theory and the latest research methods. However, there is little research on whether the field strength of unknown extremely large and extremely small pulse signals can be detected at the same time. In order to achieve this function, some scholars have proposed the following research ideas: (1) Segmented multiplication method: divide the input end into different dynamic segments, and select the corresponding measurement segment according to different input levels. Obviously, at a certain moment, due to inappropriate measurement sensitivity, weak signals will be lost. Or the transient level of the peak value cannot be collected due to inappropriate dynamics; (2) Automatic gain control method: make the pre-amplifier and even the intermediate frequency amplifier part into a circuit with automatic gain (AGC) function, so as to maximize the requirements of different signal input levels. Thereby effectively expanding the input dynamic range. This is a relatively effective method at present and is widely used. However, the above methods generally have some difficult to overcome problems: first, the circuit is complex, not only the front-end circuit must have a large range of AGC control to meet the requirements of a wide range, but also to ensure that the circuit with sufficient conditions for the output of the large dynamic of the back stage is designed. Especially for the analog display part, it is necessary to ensure large dynamics and sufficient linearity of the circuit. Therefore, the circuit is required to have sufficient power reserve. Secondly, it is difficult for the circuit to achieve long-term stability. Due to the complex circuit and numerous circuit links, the circuit operation places high demands on the environment. In particular, the influence of temperature often requires the instrument to have a sufficiently long warm-up time. Even so, it is difficult to guarantee the change of measurement accuracy in the application, especially for instruments with DC amplifier circuits, and it is even more difficult to guarantee long-term stability.

[0006] The system of the present invention constructs a pulse field strength test system with a large dynamic range by introducing microwave devices such as gas discharge tubes, and provides a specific test method. The pulse signal field strength amplitude measurement range (6.14×10 -5 ~6.14×10 3 )V / m, and the signal power can cover the range of -80dbm to 80dBm. The test system can realize high-precision measurement of the electric field strength of pulse signals with unknown power levels. Summary of the invention

[0007] In view of the above-mentioned shortcomings of the prior art, the purpose of the present invention is to use microwave devices such as directional couplers and gas discharge tubes to establish a set of ultra-large dynamic range pulse field strength test system and method to achieve ultra-large dynamic range pulse field strength measurement.

[0008] To achieve the above-mentioned purpose of the invention, the technical solution of the present invention is as follows:

[0009] The ultra-large dynamic range pulse field strength test system is shown in the attached figure, including a pulse signal receiving front end Ⅰ, a first-level weak signal detection link Ⅱ, a second-level medium-intensity signal detection circuit Ⅲ, a third-level high-intensity signal detection circuit Ⅳ and a signal field strength calculation module Ⅴ;

[0010] The pulse signal receiving front end I is an ultra-wideband horn antenna for receiving unknown pulse signals to be tested; the first-level weak signal detection link II is used for signal power range: -80dBm<P1≤-20dBm, field strength range: 6.14×10 -5 V / m<E1≤0.06V / m pulse signal field strength test; the second level medium strength signal detection link III is used for signal power range: -20dBm<P1≤30dBm, field strength range: 0.06V / m<E2≤19.42V / m pulse signal field strength test; the third level high strength signal detection link IV is used for power range: 30dBm<P1≤80dBm, field strength range: 19.42V / m<E2≤6.14×10 3 The signal field strength calculation module V is used to perform high-precision measurement and calibration of the pulse signal field strength.

[0011] As a preferred embodiment, the first-stage weak signal detection link II includes a first directional coupler 2, a first gas discharge tube 3, a low-noise amplifier 4, and a first microwave detector 5 connected in sequence through a coaxial cable; wherein the first directional coupler 2 is used to couple the fully reflected signal in the first-stage weak signal detection link II, and then send the coupled signal to the second-stage medium-intensity signal detection circuit III for detection; the first gas discharge tube 3 is used to block the pulse signal exceeding a certain threshold value, so as to protect the low-noise amplifier 4 and the first microwave detector 5 in the link from being damaged by the pulse signal exceeding the working power level range. injury; a low noise amplifier 4 is used to perform low noise amplification on weak signals; a first microwave detector 5 is used to detect weak signals; an ultra-wideband horn antenna is connected to a through-end 14 of a first directional coupler via a coaxial cable, an input end 15 of the first directional coupler is connected to a first gas discharge tube 3 via a coaxial cable, an isolation end 16 of the first directional coupler is connected to a first matching load 18, and a coupling end 17 of the first directional coupler is connected to a through-end 19 of a second directional coupler via a coaxial cable; the first microwave detector 5 is connected to an AD conversion module 12 in a signal field strength calculation module V via a coaxial cable.

[0012] As a preferred embodiment, the second-stage medium-intensity signal detection circuit III includes a second directional coupler 6, a second gas discharge tube 7, a first microwave attenuator 8, and a second microwave detector 9 connected in sequence by coaxial cables; wherein the second directional coupler 6 is used to couple the fully transmitted signal in the second-stage medium-intensity signal detection circuit III, and then send the coupled signal to the third-stage high-intensity signal detection circuit IV for detection; the second gas discharge tube 7 is used to block the pulse signal exceeding a certain threshold, so as to protect the first microwave attenuator 8 and the second microwave detector 9 in the link from exceeding their working power level range. The first microwave attenuator 8 is used to appropriately attenuate the medium-intensity signal so that the second microwave detector 9 works in the linear region; the second microwave detector 9 is used to detect the pulse signal in this link; the isolation end 21 of the second directional coupler is connected to the second matching load 23, the input end 20 of the second directional coupler is connected to the second gas discharge tube 7 through a coaxial cable, the coupling end 22 of the second directional coupler is connected to the second microwave attenuator 10 through a coaxial cable, and the second microwave detector 9 is connected to the AD conversion module 12 in the signal field strength calculation module V through a coaxial cable.

[0013] As a preferred embodiment, the third-level high-intensity signal detection circuit IV includes a second microwave attenuator 10 and a third microwave detector 11 connected in sequence by coaxial cables; wherein the second microwave attenuator 10 is used to attenuate the high-intensity signal coupled by the second-level medium-intensity signal detection circuit III through the second directional coupler 6, so that the third microwave detector 11 works in the linear region; the third microwave detector 11 is used to detect the pulse signal in this link. The second microwave detector 10 is connected to the third microwave detector 11 through a coaxial cable, and the third microwave detector 11 is connected to the AD conversion module 12 in the signal field strength calculation module V through a coaxial cable. As a preferred embodiment, the signal field strength calculation module V includes an AD conversion module 12 and a data processing center 13. The weak signal in the first-level weak signal detection link II is detected by the first microwave detector 5, the medium-strength signal in the second-level medium-strength signal detection circuit III is detected by the second microwave detector 9, and the high-strength signal in the third-level high-strength signal detection circuit IV is detected by the third microwave detector 11. They are all connected to the AD conversion module 12 in the signal field strength calculation module V through a coaxial cable, and the AD conversion module 12 is connected to the data processing center 13 through a network cable.

[0014] The present invention realizes graded detection of pulse signal field strengths at different power levels by introducing a gas discharge tube and a directional coupler, and realizes precise measurement of pulse field strengths in an ultra-large dynamic range.

[0015] The specific test process of the ultra-large dynamic range pulse field strength test system and method is as follows: the ultra-wideband horn antenna 1 receives a pulse signal of unknown power level and passes through the first directional coupler 2 to reach the first gas discharge tube 3. At this time, if the received signal is a weak signal, the signal passes through the first gas discharge tube 3 almost without loss, and then passes through the low noise amplifier 4. The signal is amplified and then detected by the first microwave detector 5. The detected data is transmitted to the AD conversion module 12 through the coaxial cable. After the AD conversion module 12 obtains the digital signal, it sends the data to the data processing center 13 through the network cable. The data processing center 13 completes the calculation of the field strength amplitude; if the intensity of the pulse signal reaching the first gas discharge tube 3 exceeds the working threshold of the first gas discharge tube 3, the first gas discharge tube 3 will be punctured by air. At this time, the pulse signal will be totally reflected. After the signal is reflected, it passes through the coupling end 17 of the first directional coupler to attenuate the signal and then sends it to the second-stage medium-intensity signal detection circuit III. At this time, the signal passes through the second directional coupler 6 and enters the second-stage medium-intensity signal detection circuit III. Second gas discharge tube 7, at this time, if the signal strength is less than the working threshold of the second gas discharge tube 7, the signal enters the first microwave attenuator 8, the signal will be appropriately attenuated after passing through the first microwave attenuator 8, and then enters the second microwave detector 9 for detection, and then the detection data is sent to the AD conversion module 12, and the digital signal processed by the AD conversion module 12 is sent to the data processing center 13 for field strength amplitude calculation; if the pulse signal strength reaching the second gas discharge tube 7 exceeds the working threshold of the second gas discharge tube 7, the second gas discharge tube 7 will be broken down by air, and at this time the pulse signal will be totally reflected, and after the signal is reflected, the signal will be attenuated by the coupling end 22 of the second directional coupler and then sent to the third-level high-intensity signal detection circuit IV, at this time, the signal is appropriately attenuated by the second microwave attenuator 10 and sent to the third microwave detector for detection, the detected data is sent to the AD conversion module 12, and the digital signal processed by the AD conversion module 12 is sent to the data processing center 13 for field strength amplitude calculation.

[0016] In order to achieve the above-mentioned object of the invention, the present invention also provides a method for testing pulse field strength using the above-mentioned device, comprising the following steps:

[0017] Step 1: Connect the test system;

[0018] Step 2: Analyze and compare the data after the AD conversion module 12 to determine the power level of the pulse signal to be measured, that is, to determine whether the pulse signal to be measured is measured through the first-level weak signal detection link II, the second-level medium-intensity signal detection circuit III, or the third-level high-intensity signal detection circuit IV;

[0019] Step 3: After determining the power level of the pulse signal to be tested in step 2, it is possible to determine which link is used to calculate the pulse signal field strength. The pulse signal field strength calculation formulas are as follows:

[0020] First, the first microwave detector 5, the second microwave detector 9 and the third microwave detector 11 are calibrated to obtain the relationship between different detection voltages U and the input signal power P, that is:

[0021] U~P(1)

[0022] If the power of the pulse signal to be measured is ≤-20dBm, the voltage amplitude of the signal is obtained by the AD conversion module 12 after the signal is detected by the first-level weak signal detection link II. Assuming its value is U0, the power at the input end of the microwave detector 5 can be obtained as P0 according to the above formula (1). At this time, the magnitude of the field strength E0 of the pulse signal to be measured is calculated according to formula (2):

[0023]

[0024] Among them, G is the gain of the low noise amplifier, L1 is the insertion loss of the first gas discharge tube 3, L2 is the insertion loss of the first directional coupler 2, L3 is the total insertion loss of the coaxial cable connecting the ultra-wideband horn antenna 1 and the first directional coupler 2, connecting the first directional coupler 2 and the first gas discharge tube 3, connecting the first gas discharge tube 3 and the low noise amplifier 4, and connecting the low noise amplifier and the first microwave detector 5 in the first-level weak signal detection link II, R is the free space wave impedance, and a is the coupling coefficient of the ultra-wideband horn antenna 1.

[0025] If the power of the pulse signal to be measured is greater than -20dBm, after reaching the first gas discharge tube 3, the first gas discharge tube 3 will be punctured by air. At this time, the signal is totally reflected and coupled to the second-stage medium-intensity signal detection circuit III by the coupling end 17 of the first directional coupler 2. If the signal strength does not exceed the working threshold of the second gas discharge tube 7 at this time, the signal is detected by the second microwave detector 9 in the second-stage medium-intensity signal detection circuit III and then sent to the AD conversion module to obtain the detected digital voltage. If its value is U1, then according to formula (1), the input power of the second microwave detector 9 can be obtained as P1. At this time, the magnitude of the field strength E0 of the pulse signal to be measured is calculated according to formula (3):

[0026]

[0027] Among them, A is the attenuation of the first microwave attenuator 8, L4 is the insertion loss of the second gas discharge tube 7, L5 is the insertion loss of the second directional coupler 6, L6 is the coupling degree of the first directional coupler 2, and L7 is the total insertion loss of the coaxial cable connecting the ultra-wideband horn antenna 1 and the first directional coupler 2, connecting the first directional coupler 2 and the first gas discharge tube 3, connecting the first directional coupler 2 and the second directional coupler 6, connecting the second directional coupler 6 and the second gas discharge tube 7, connecting the second gas discharge tube 7 and the first microwave attenuator 8, and connecting the first microwave attenuator 8 and the second microwave detector 9 in the first-level weak signal detection link II.

[0028] If the power of the pulse signal to be measured is greater than 30 dBm, the second gas discharge tube 7 will be punctured by air after reaching the second gas discharge tube 7. At this time, the signal is totally reflected and coupled to the third-stage high-intensity signal detection circuit IV by the coupling end 22 of the second directional coupler 6. The signal is attenuated to the linear working area of ​​the third microwave detector 11 by the second microwave attenuator 10. Assuming that the digital voltage value after detection by the third microwave detector 11 and sent to the AD conversion module is U2, then according to formula (1), the input power of the second microwave detector 11 can be obtained as P2. At this time, the magnitude of the field strength E0 of the pulse signal to be measured is calculated according to formula (4):

[0029]

[0030] Wherein, B is the attenuation of the second microwave attenuator 10, L8 is the coupling degree of the second directional coupler 6, L9 is the coupling degree of the first directional coupler 2, and L 10 The total insertion loss of the coaxial cable connecting the third microwave detector 11 and the second microwave attenuator 10, connecting the second microwave attenuator 10 and the coupling end of the second directional coupler 6, connecting the second directional coupler 6 and the second gas discharge tube 7, connecting the second directional coupler 6 and the coupling end of the first directional coupler 2, connecting the first directional coupler 2 and the first gas discharge tube 3, and connecting the first directional coupler 2 and the ultra-wideband horn antenna 1.

[0031] The beneficial effects of the present invention are:

[0032] 1. The introduction of gas discharge tubes allows for graded measurement of signal field strengths of different strengths, improving the measurement dynamic range of the test system.

[0033] 2. This system can simultaneously measure pulse signals of unknown signal strength in a wide frequency band with high precision, and has the characteristics of simple circuit construction and long-term stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a structural diagram of this system.

[0035] Among them, 1 is an ultra-wideband horn antenna, 2 is a first directional coupler, 3 is a first gas discharge tube, 4 is a low noise amplifier, 5 is a first microwave detector, 6 is a second directional coupler, 7 is a second gas discharge tube, 8 is a first microwave attenuator, 9 is a second microwave detector, 10 is a second microwave attenuator, 11 is a third microwave detector, 12 is an AD conversion module, 13 is a data processing center, 14 is a through-end of the first directional coupler, 15 is an input end of the first directional coupler, 16 is an isolation end of the first directional coupler, 17 is a coupling end of the first directional coupler, 18 is a first matching load, 19 is a through-end of the second directional coupler, 20 is an input end of the second directional coupler, 21 is an isolation end of the second directional coupler, 22 is a coupling end of the second directional coupler, and 23 is a second matching load. DETAILED DESCRIPTION

[0036] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0037] An ultra-large dynamic range pulse field strength test system comprises a pulse signal receiving front end I, a first-level weak signal detection link II, a second-level medium-intensity signal detection circuit III, a third-level high-intensity signal detection circuit IV and a signal field strength calculation module V;

[0038] The pulse signal receiving front end I is an ultra-wideband horn antenna for receiving unknown pulse signals to be tested; the first-level weak signal detection link II is used for signal power range: -80dBm<P1≤-20dBm, field strength range: 6.14×10 -5 V / m<E1≤0.06V / m pulse signal field strength test; the second level medium strength signal detection link III is used for signal power range: -20dBm<P1≤30dBm, field strength range: 0.06V / m<E2≤19.42V / m pulse signal field strength test; the third level high strength signal detection link IV is used for power range: 30dBm<P1≤80dBm, field strength range: 19.42V / m<E2≤6.14×10 3 The signal field strength calculation module V is used to measure and calibrate the pulse signal field strength.

[0039] The pulse signal receiving front end I, the first-level weak signal detection link II, the second-level medium-intensity signal detection circuit III, the third-level high-intensity signal detection circuit IV and the signal field strength calculation module V are all connected through a coaxial cable.

[0040] The first-stage weak signal detection link II comprises a first directional coupler 2, a first gas discharge tube 3, a low-noise amplifier 4, and a first microwave detector 5 connected in sequence through a coaxial cable; wherein the first directional coupler 2 is used to couple the fully reflected signal in the first-stage weak signal detection link II, and then send the coupled signal to the second-stage medium-intensity signal detection circuit III for detection; the first gas discharge tube 3 is used to block the pulse signal exceeding a certain threshold value, so as to protect the low-noise amplifier 4 and the first microwave detector 5 in the link from being damaged by the pulse signal exceeding the working power level range; The noise amplifier 4 is used to perform low-noise amplification on weak signals; the first microwave detector 5 is used to detect weak signals; the ultra-wideband horn antenna is connected to the through-end 14 of the first directional coupler through a coaxial cable, the input end 15 of the first directional coupler is connected to the first gas discharge tube 3 through a coaxial cable, the isolation end 16 of the first directional coupler is connected to the first matching load 18, and the coupling end 17 of the first directional coupler is connected to the through-end 19 of the second directional coupler through a coaxial cable; the first microwave detector 5 is connected to the AD conversion module 12 in the signal field strength calculation module V through a coaxial cable.

[0041] The second-stage medium-intensity signal detection circuit III comprises a second directional coupler 6, a second gas discharge tube 7, a first microwave attenuator 8, and a second microwave detector 9 connected in sequence by a coaxial cable; wherein the second directional coupler 6 is used to couple the fully transmitted signal in the second-stage medium-intensity signal detection circuit III, and then send the coupled signal to the third-stage high-intensity signal detection circuit IV for detection; the second gas discharge tube 7 is used to block the pulse signal exceeding a certain threshold, so as to protect the first microwave attenuator 8 and the second microwave detector 9 in the link from pulses exceeding their working power level range. Signal damage; the first microwave attenuator 8 is used to appropriately attenuate the medium-intensity signal so that the second microwave detector 9 works in the linear region; the second microwave detector 9 is used to detect the pulse signal in this link; the isolation end 21 of the second directional coupler is connected to the second matching load 23, the input end 20 of the second directional coupler is connected to the second gas discharge tube 7 through a coaxial cable, the coupling end 22 of the second directional coupler is connected to the second microwave attenuator 10 through a coaxial cable, and the second microwave detector 9 is connected to the AD conversion module 12 in the signal field strength calculation module V through a coaxial cable.

[0042] The third-level high-intensity signal detection circuit IV includes a second microwave attenuator 10 and a third microwave detector 11 connected in sequence by coaxial cables; wherein the second microwave attenuator 10 is used to attenuate the high-intensity signal coupled by the second-level medium-intensity signal detection circuit III through the second directional coupler 6, so that the third microwave detector 11 works in the linear region; the third microwave detector 11 is used to detect the pulse signal in this link. The second microwave detector 10 is connected to the third microwave detector 11 through a coaxial cable, and the third microwave detector 11 is connected to the AD conversion module 12 in the signal field strength calculation module V through a coaxial cable. The signal field strength calculation module V includes an AD conversion module 12 and a data processing center 13. The weak signal in the first-level weak signal detection link II is detected by the first microwave detector 5, the medium-strength signal in the second-level medium-strength signal detection circuit III is detected by the second microwave detector 9, and the high-strength signal in the third-level high-strength signal detection circuit IV is detected by the third microwave detector 11. They are all connected to the AD conversion module 12 in the signal field strength calculation module V through a coaxial cable, and the AD conversion module 12 is connected to the data processing center 13 through a network cable.

[0043] The present invention realizes graded detection of pulse signal field strengths at different power levels by introducing a gas discharge tube and a directional coupler, and realizes precise measurement of pulse field strengths in an ultra-large dynamic range.

[0044] The specific test process of the ultra-large dynamic range pulse field strength test system and method is as follows: the ultra-wideband horn antenna 1 receives a pulse signal of unknown power level and passes through the first directional coupler 2 to reach the first gas discharge tube 3. At this time, if the received signal is a weak signal, the signal passes through the first gas discharge tube 3 almost without loss, and then passes through the low noise amplifier 4. The signal is amplified and then detected by the first microwave detector 5. The detected data is transmitted to the AD conversion module 12 through the coaxial cable. After the AD conversion module 12 obtains the digital signal, it sends the data to the data processing center 13 through the network cable. The data processing center 13 completes the calculation of the field strength amplitude; if the intensity of the pulse signal reaching the first gas discharge tube 3 exceeds the working threshold of the first gas discharge tube 3, the first gas discharge tube 3 will be punctured by air. At this time, the pulse signal will be totally reflected. After the signal is reflected, it passes through the coupling end 17 of the first directional coupler to attenuate the signal and then sends it to the second-stage medium-intensity signal detection circuit III. At this time, the signal passes through the second directional coupler 6 and enters the second-stage medium-intensity signal detection circuit III. Second gas discharge tube 7, at this time, if the signal strength is less than the working threshold of the second gas discharge tube 7, the signal enters the first microwave attenuator 8, the signal will be appropriately attenuated after passing through the first microwave attenuator 8, and then enters the second microwave detector 9 for detection, and then the detection data is sent to the AD conversion module 12, and the digital signal processed by the AD conversion module 12 is sent to the data processing center 13 for field strength amplitude calculation; if the pulse signal strength reaching the second gas discharge tube 7 exceeds the working threshold of the second gas discharge tube 7, the second gas discharge tube 7 will be broken down by air, and at this time the pulse signal will be totally reflected, and after the signal is reflected, the signal will be attenuated by the coupling end 22 of the second directional coupler and then sent to the third-level high-intensity signal detection circuit IV, at this time, the signal is appropriately attenuated by the second microwave attenuator 10 and sent to the third microwave detector for detection, the detected data is sent to the AD conversion module 12, and the digital signal processed by the AD conversion module 12 is sent to the data processing center 13 for field strength amplitude calculation.

[0045] The method for performing pulse signal field strength testing using the above test system comprises the following steps:

[0046] Step 1: Follow the instructions Figure 1 Connect the test system;

[0047] Step 2: Analyze and compare the data after the AD conversion module 12 to determine the power level of the pulse signal to be measured, that is, to determine whether the pulse signal to be measured is measured through the first-level weak signal detection link II, the second-level medium-intensity signal detection circuit III, or the third-level high-intensity signal detection circuit IV;

[0048] Step 3: After determining the power level of the pulse signal to be tested in step 2, it is possible to determine which link is used to calculate the pulse signal field strength. The pulse signal field strength calculation formulas are as follows:

[0049] First, the first microwave detector 5, the second microwave detector 9 and the third microwave detector 11 are calibrated to obtain the relationship between different detection voltages U and the input signal power P, that is:

[0050] U~P(1)

[0051] If the power of the pulse signal to be measured is ≤-20dBm, the voltage amplitude of the signal is obtained by the AD conversion module 12 after the signal is detected by the first-level weak signal detection link II. Assuming its value is U0, the power at the input end of the microwave detector 5 can be obtained as P0 according to the above formula (1). At this time, the magnitude of the field strength E0 of the pulse signal to be measured is calculated according to formula (2):

[0052]

[0053] Among them, G is the gain of the low noise amplifier, L1 is the insertion loss of the first gas discharge tube 3, L2 is the insertion loss of the first directional coupler 2, L3 is the total insertion loss of the coaxial cable connecting the ultra-wideband horn antenna 1 and the first directional coupler 2, connecting the first directional coupler 2 and the first gas discharge tube 3, connecting the first gas discharge tube 3 and the low noise amplifier 4, and connecting the low noise amplifier and the first microwave detector 5 in the first-level weak signal detection link II, R is the free space wave impedance, and a is the coupling coefficient of the ultra-wideband horn antenna 1.

[0054] If the power of the pulse signal to be measured is greater than -20dBm, after reaching the first gas discharge tube 3, the first gas discharge tube 3 will be punctured by air. At this time, the signal is totally reflected and coupled to the second-stage medium-intensity signal detection circuit III by the coupling end 17 of the first directional coupler 2. If the signal strength does not exceed the working threshold of the second gas discharge tube 7 at this time, the signal is detected by the second microwave detector 9 in the second-stage medium-intensity signal detection circuit III and then sent to the AD conversion module to obtain the detected digital voltage. If its value is U1, then according to formula (1), the input power of the second microwave detector 9 can be obtained as P1. At this time, the magnitude of the field strength E0 of the pulse signal to be measured is calculated according to formula (3):

[0055]

[0056] Among them, A is the attenuation of the first microwave attenuator 8, L4 is the insertion loss of the second gas discharge tube 7, L5 is the insertion loss of the second directional coupler 6, L6 is the coupling degree of the first directional coupler 2, and L7 is the total insertion loss of the coaxial cable connecting the ultra-wideband horn antenna 1 and the first directional coupler 2, connecting the first directional coupler 2 and the first gas discharge tube 3, connecting the first directional coupler 2 and the second directional coupler 6, connecting the second directional coupler 6 and the second gas discharge tube 7, connecting the second gas discharge tube 7 and the first microwave attenuator 8, and connecting the first microwave attenuator 8 and the second microwave detector 9 in the first-level weak signal detection link II.

[0057] If the power of the pulse signal to be measured is greater than 30 dBm, the second gas discharge tube 7 will be punctured by air after reaching the second gas discharge tube 7. At this time, the signal is totally reflected and coupled to the third-stage high-intensity signal detection circuit IV by the coupling end 22 of the second directional coupler 6. The signal is attenuated to the linear working area of ​​the third microwave detector 11 by the second microwave attenuator 10. Assuming that the digital voltage value after detection by the third microwave detector 11 and sent to the AD conversion module is U2, then according to formula (1), the input power of the second microwave detector 11 can be obtained as P2. At this time, the magnitude of the field strength E0 of the pulse signal to be measured is calculated according to formula (4):

[0058]

[0059] Wherein, B is the attenuation of the second microwave attenuator 10, L8 is the coupling degree of the second directional coupler 6, L9 is the coupling degree of the first directional coupler 2, and L 10 The total insertion loss of the coaxial cable connecting the third microwave detector 11 and the second microwave attenuator 10, connecting the second microwave attenuator 10 and the coupling end of the second directional coupler 6, connecting the second directional coupler 6 and the second gas discharge tube 7, connecting the second directional coupler 6 and the coupling end of the first directional coupler 2, connecting the first directional coupler 2 and the first gas discharge tube 3, and connecting the first directional coupler 2 and the ultra-wideband horn antenna 1.

[0060] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical ideas disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. An ultra-large dynamic range pulse field strength test system, characterized by: It includes a pulse signal receiving front end Ⅰ, a first-level weak signal detection link Ⅱ, a second-level medium-intensity signal detection circuit Ⅲ, a third-level high-intensity signal detection circuit Ⅳ and a signal field strength calculation module Ⅴ; The pulse signal receiving front end I is an ultra-wideband horn antenna for receiving unknown pulse signals to be tested; the first-level weak signal detection link II is used for signal power range: -80dBm<P1≤-20dBm, field strength range: 6.14×10 - 5 V / m<E1≤0.06V / m pulse signal field strength test; the second level medium strength signal detection link III is used for signal power range: -20dBm<P1≤30dBm, field strength range: 0.06V / m<E2≤19.42V / m pulse signal field strength test; the third level high strength signal detection link IV is used for power range: 30dBm<P1≤80dBm, field strength range: 19.42V / m<E2≤6.14×10 3 V / m pulse signal to perform field strength test; the signal field strength calculation module V is used to measure and calibrate the pulse signal field strength; The first-stage weak signal detection link II comprises a first directional coupler (2), a first gas discharge tube (3), a low-noise amplifier (4), and a first microwave detector (5) which are connected in sequence via a coaxial cable; wherein the first directional coupler (2) is used to couple the fully reflected signal in the first-stage weak signal detection link II, and then send the coupled signal to the second-stage medium-intensity signal detection circuit III for detection; the first gas discharge tube (3) is used to block pulse signals exceeding a certain threshold value, thereby protecting the low-noise amplifier (4) and the first microwave detector (5) in the link from being damaged by pulse signals exceeding their operating power level range; The low noise amplifier (4) is used for low noise amplification of weak signals; the first microwave detector (5) is used for detecting weak signals; the ultra-wideband horn antenna is connected to the through end (14) of the first directional coupler via a coaxial cable; the input end (15) of the first directional coupler is connected to the first gas discharge tube (3) via a coaxial cable; the isolation end (16) of the first directional coupler is connected to the first matching load (18); the coupling end (17) of the first directional coupler is connected to the through end (19) of the second directional coupler via a coaxial cable; the first microwave detector (5) is connected to the AD conversion module (12) in the signal field strength calculation module V via a coaxial cable.

2. The ultra-large dynamic range pulse field strength test system according to claim 1, characterized in that: The second-stage medium-intensity signal detection circuit III comprises a second directional coupler (6), a second gas discharge tube (7), a first microwave attenuator (8), and a second microwave detector (9) connected in sequence by a coaxial cable; wherein the second directional coupler (6) is used to couple the fully transmitted signal in the second-stage medium-intensity signal detection circuit III, and then send the coupled signal to the third-stage high-intensity signal detection circuit IV for detection; the second gas discharge tube (7) is used to block the pulse signal exceeding a certain threshold value, thereby protecting the first microwave attenuator (8) and the second microwave detector (9) in the link from being damaged by the pulse signal exceeding their working power level range. The invention relates to a first microwave attenuator (8) for appropriately attenuating a medium-intensity signal so that the second microwave detector (9) operates in a linear region; the second microwave detector (9) is used to detect a pulse signal in the link; the isolation end (21) of the second directional coupler is connected to a second matching load (23); the input end (20) of the second directional coupler is connected to a second gas discharge tube (7) via a coaxial cable; the coupling end (22) of the second directional coupler is connected to a second microwave attenuator (10) via a coaxial cable; and the second microwave detector (9) is connected to an AD conversion module (12) in a signal field strength calculation module V via a coaxial cable.

3. The ultra-large dynamic range pulse field strength test system according to claim 1, characterized in that: The third-level high-intensity signal detection circuit IV comprises a second microwave attenuator (10) and a third microwave detector (11) which are connected in sequence by a coaxial cable; wherein the second microwave attenuator (10) is used to attenuate the high-intensity signal coupled by the second-level medium-intensity signal detection circuit III via a second directional coupler (6), so that the third microwave detector (11) operates in a linear region; the third microwave detector (11) is used to detect the pulse signal in the link; the second microwave detector (10) is connected to the third microwave detector (11) via a coaxial cable, and the third microwave detector (11) is connected to an AD conversion module (12) in a signal field strength calculation module V via a coaxial cable.

4. The ultra-large dynamic range pulse field strength test system according to claim 1, characterized in that: The signal field strength calculation module V comprises an AD conversion module (12) and a data processing center (13); the weak signal in the first-level weak signal detection link II is detected by a first microwave detector (5), the medium-strength signal in the second-level medium-strength signal detection circuit III is detected by a second microwave detector (9), and the high-strength signal in the third-level high-strength signal detection circuit IV is detected by a third microwave detector (11), all of which are connected to the AD conversion module (12) in the signal field strength calculation module V through a coaxial cable; the AD conversion module (12) is connected to the data processing center (13) through a network cable.

5. The method for testing pulse signal field strength according to any one of claims 1 to 4, characterized in that The steps include: Step 1: Connect the test system; Step 2: Analyze and compare the data after the AD conversion module (12) to determine the power level of the pulse signal to be measured, that is, to determine whether the pulse signal to be measured is measured through the first-level weak signal detection link II, the second-level medium-intensity signal detection circuit III, or the third-level high-intensity signal detection circuit IV; Step 3: After determining the power level of the pulse signal to be measured in step 2, it is possible to determine which link is used to calculate the magnitude of the pulse signal field strength. The pulse signal field strength calculation formulas are as follows: First, the first microwave detector (5), the second microwave detector (9) and the third microwave detector (11) are calibrated to obtain the relationship between different detection voltages U and the input signal power P, namely: U~P(1) If the power of the pulse signal to be measured is ≤-20dBm, the voltage amplitude of the signal is obtained by the AD conversion module (12) after the signal is detected by the first-level weak signal detection link II. Assuming its value is U0, the power at the input end of the microwave detector (5) can be obtained as P0 according to the above formula (1). At this time, the magnitude of the field strength E0 of the pulse signal to be measured is calculated according to formula (2): Wherein, G is the gain of the low noise amplifier, L1 is the insertion loss of the first gas discharge tube (3), L2 is the insertion loss of the first directional coupler (2), L3 is the total insertion loss of the coaxial cable connecting the ultra-wideband horn antenna (1) and the first directional coupler (2), connecting the first directional coupler (2) and the first gas discharge tube (3), connecting the first gas discharge tube (3) and the low noise amplifier (4), and connecting the low noise amplifier and the first microwave detector (5) in the first-stage weak signal detection link II, R is the free space wave impedance, and a is the coupling coefficient of the ultra-wideband horn antenna (1); If the power of the pulse signal to be measured is greater than -20 dBm, after reaching the first gas discharge tube (3), the first gas discharge tube (3) is subjected to air breakdown. At this time, the signal is totally reflected and coupled to the second-stage medium-intensity signal detection circuit III by the coupling end (17) of the first directional coupler. If the signal strength does not exceed the working threshold of the second gas discharge tube (7) at this time, the signal is detected by the second microwave detector (9) in the second-stage medium-intensity signal detection circuit III and then sent to the AD conversion module to obtain a detected digital voltage. If the value of the detected digital voltage is U1, then according to formula (1), the input power of the second microwave detector (9) is P1. At this time, the magnitude of the field strength E0 of the pulse signal to be measured is calculated according to formula (3): Wherein, A is the attenuation of the first microwave attenuator (8), L4 is the insertion loss of the second gas discharge tube (7), L5 is the insertion loss of the second directional coupler (6), L6 is the coupling degree of the first directional coupler (2), and L7 is the total insertion loss of the coaxial cables connecting the ultra-wideband horn antenna (1) and the first directional coupler (2), connecting the first directional coupler (2) and the first gas discharge tube (3), connecting the first directional coupler (2) and the second directional coupler (6), connecting the second directional coupler (6) and the second gas discharge tube (7), connecting the second gas discharge tube (7) and the first microwave attenuator (8), and connecting the first microwave attenuator (8) and the second microwave detector (9) in the first-stage weak signal detection link II; If the power of the pulse signal to be measured is greater than 30 dBm, the second gas discharge tube (7) will be punctured by air after reaching the second gas discharge tube (7). At this time, the signal will be totally reflected and coupled to the third-stage high-intensity signal detection circuit IV by the coupling end (22) of the second directional coupler. The signal will be attenuated to the linear working area of ​​the third microwave detector (11) by the second microwave attenuator (10). Assuming that the digital voltage value after detection by the third microwave detector (11) and sent to the AD conversion module is U2, then according to formula (1), the input power of the second microwave detector (11) can be obtained as P2. At this time, the magnitude of the field strength E0 of the pulse signal to be measured is calculated according to formula (4): Wherein, B is the attenuation of the second microwave attenuator (10), L8 is the coupling degree of the second directional coupler (6), L9 is the coupling degree of the first directional coupler (2), and L 10 The invention relates to a total insertion loss of a coaxial cable connecting a third microwave detector (11) and a second microwave attenuator (10), connecting the second microwave attenuator (10) and a coupling end of a second directional coupler (6), connecting the second directional coupler (6) and a second gas discharge tube (7), connecting the second directional coupler (6) and a coupling end of a first directional coupler (2), connecting the first directional coupler (2) and a first gas discharge tube (3), and connecting the first directional coupler (2) and an ultra-wideband horn antenna (1).

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