Shielded multi-core wire coupled strong field electromagnetic radiation equivalent injection test method and system

Abstract

The present invention provides a shielded multi-core cable coupled strong field electromagnetic radiation equivalent injection test method and system, irradiates the target cable, records the irradiation response value of the target cable; inserts a current injection probe at each end of the target cable, connects the two current injection probes to a matching load and a signal source respectively, and records the current injection response value of the target cable; calculates the amplitude ratio and phase difference of the shielded multi-core cable according to the irradiation response value and the current injection response value; determines the equivalent injection excitation source based on the amplitude ratio and the phase difference; performs a high field strength extrapolation test based on the equivalent injection excitation source, and completes the electromagnetic radiation effect test process. By using two current injection probes to perform double-end current injection at both ends of the shielded multi-core cable, and adding the amplitude ratio and the phase difference to determine the equivalent corresponding relationship, the equivalent injection test of the multi-core shielded cable is completed.

Description

Technical Field

[0001] The invention belongs to the technical field of electromagnetic radiation effects, and in particular relates to a shielded multi-core wire coupled strong field electromagnetic radiation equivalent injection test method and system. Background Art

[0002] Weapons and equipment need to use anti-interference, efficient and safe interconnection cables, and shielded multi-core cables are a commonly used type. In the future information battlefield, high-power radio frequency electromagnetic radiation fields have brought the most severe challenges to weapons and equipment, integrated electronic information systems, etc. Various devices or subsystems are often interconnected through cables to achieve information transmission and power transmission, which leads to a high probability that the weak link of electromagnetic protection will appear in the cable coupling channel. Therefore, it is necessary to conduct strong field electromagnetic radiation effect tests on weapons and equipment.

[0003] For this reason, strong field radiation effect equivalent test technology has received more and more attention from researchers, such as the current injection method. Among the many current injection methods, the large current injection technology is relatively more mature. However, this method uses the response signal for linear extrapolation and is not suitable for nonlinear systems. It can only be applied in the interconnection system of shielded two-core cables, and further research is needed for multi-core shielded cables. Summary of the invention

[0004] In view of this, the present invention provides a shielded multi-core wire coupled strong field electromagnetic radiation equivalent injection test method and system, aiming to solve the problem that the current injection method in the prior art is difficult to perform equivalent injection test on multi-core shielded cables.

[0005] A first aspect of an embodiment of the present invention provides a shielded multi-core wire coupled strong field electromagnetic radiation equivalent injection test method, comprising:

[0006] Irradiate the target cable and record the irradiation response value of the target cable;

[0007] Insert a current injection probe at each end of the target cable, connect the two current injection probes to the matching load and the signal source respectively, and record the current injection response value of the target cable;

[0008] Calculate the amplitude ratio and phase difference of the shielded multi-core cable based on the irradiation response value and the current injection response value;

[0009] Determine the equivalent injection excitation source based on the amplitude ratio and phase difference;

[0010] Based on the equivalent injection excitation source, a high field strength extrapolation test is carried out to complete the electromagnetic radiation effect test process.

[0011] A second aspect of an embodiment of the present invention provides an equivalent electromagnetic radiation effect test system, comprising: a coaxial load, a shielded multi-core cable, an antenna, a signal source, a first current injection probe, a second current injection probe, a matching load, a through load, a signal conversion module, and a receiver;

[0012] The coaxial load, the multi-core cable, the antenna, the first current injection probe, the second current injection probe, the matching load, and the through-type load are all arranged in the microwave darkroom;

[0013] The first current injection probe and the second current injection probe are respectively arranged at two ends of the shielded multi-core cable; the coaxial load is connected to the first end of the shielded multi-core cable; the through-type load is connected to the second end of the shielded multi-core cable; and the signal conversion module is used to connect the through-type load arranged in the microwave darkroom with the receiver outside the microwave darkroom.

[0014] The shielded multi-core cable coupled strong field electromagnetic radiation equivalent injection test method and system provided by the embodiment of the present invention irradiates the target cable and records the irradiation response value of the target cable; inserts a current injection probe at each end of the target cable, connects the two current injection probes to the matching load and the signal source respectively, and records the current injection response value of the target cable; calculates the amplitude ratio and phase difference of the shielded multi-core cable according to the irradiation response value and the current injection response value; determines the equivalent injection excitation source based on the amplitude ratio and the phase difference; performs a high field strength extrapolation test based on the equivalent injection excitation source to complete the electromagnetic radiation effect test process. By using two current injection probes to perform double-end current injection at both ends of the shielded multi-core cable, and adding the amplitude ratio and phase difference to determine the equivalent corresponding relationship, the equivalent injection test of the multi-core shielded cable is completed. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0016] Figure 1 It is a structural schematic diagram of an equivalent electromagnetic radiation effect test system provided by an embodiment of the present invention;

[0017] Figure 2 It is a structural schematic diagram of an equivalent electromagnetic radiation effect test system during irradiation provided by an embodiment of the present invention;

[0018] Figure 3 It is a structural schematic diagram of an equivalent electromagnetic radiation effect test system during current injection provided by an embodiment of the present invention;

[0019] Figure 4 It is a schematic diagram of the structure of the shielded multi-core wire interconnection system;

[0020] Figure 5 It is a schematic diagram of the structure of the cross section of a shielded multi-core wire;

[0021] Figure 6 It is the equivalent circuit diagram of double-ended injection shielding layer;

[0022] Figure 7 It is the circuit diagram of the transmission line inside the shielded cable;

[0023] Figure 8 It is a flow chart for realizing a shielded multi-core wire coupled strong field electromagnetic radiation equivalent injection test method provided by an embodiment of the present invention;

[0024] Fig. 9 It is a schematic diagram of the structure of a shielded eight-core cable;

[0025] Fig.10 It is an irradiation simulation model under low field strength conditions;

[0026] Fig.11 It is an injection simulation model under low field strength conditions;

[0027] Fig.12 It is the result of low field strength simulation test;

[0028] Fig.13 It is the result of high field strength simulation test;

[0029] Fig.14 It is the terminal response of the line to I under irradiation and three equivalent injection modes during the low field strength pre-experiment;

[0030] Fig.15 It is the terminal response of line pair II under irradiation and three equivalent injection modes during low field strength pre-experiment;

[0031] Fig.16 It is the terminal response of line pair III under irradiation and three equivalent injection modes during low field strength pre-experiment;

[0032] Fig.17 It is the terminal response of the line to I under irradiation and three equivalent injection modes in the high field strength extrapolation experiment;

[0033] Fig.18 It is the terminal response of line pair II under irradiation and three equivalent injection modes in high field strength extrapolation experiment;

[0034] Fig.19 It is the terminal response of line III under irradiation and three equivalent injection modes during high field strength extrapolation experiment. DETAILED DESCRIPTION

[0035] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present invention. However, it should be clear to those skilled in the art that the present invention may be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present invention.

[0036] Figure 1 Schematic diagram of the structure of the equivalent electromagnetic radiation effect test system provided by the embodiment of the present invention. Figure 1 As shown, in some embodiments, a coaxial load 101, a shielded multi-core cable 102, an antenna 103, a signal source 104, a first current injection probe 105, a second current injection probe 106, a matching load 107, a through-type load 108, a signal conversion module 109 and a receiver 110; the coaxial load 101, the multi-core cable 102, the antenna 103, the first current injection probe 105, the second current injection probe 106, the matching load 107, and the through-type load 108 are all arranged in a microwave darkroom; the first current injection probe 105 and the second current injection probe 106 are respectively arranged at both ends of the shielded multi-core cable 102; the coaxial load 101 is connected to the first end of the shielded multi-core cable 102; the through-type load 108 is connected to the second end of the shielded multi-core cable 102; the signal conversion module 109 is used to connect the through-type load 108 arranged in the microwave darkroom with the receiver 110 outside the microwave darkroom.

[0037] The signal conversion module 109 includes two photoelectric conversion modules, which are respectively connected to the through-type load 108 and the receiver 110, and the two photoelectric conversion modules are connected via optical fibers. The receiver 110 can be a test device, a spectrum analyzer, etc., which is not limited here.

[0038] A DC regulated power supply and a power amplifier module can be used as the signal source 104, or a vector network analyzer (VNA) transmitter can be used as the signal source 104. On this basis, additional input devices can be added to form the signal source 104, or a dual-channel vector signal source can be used as the signal source 104, which is not limited here. During the test, the antenna 103, the first current injection probe 105, and the second current injection probe 106 can all be connected to the corresponding signal source. At the same time, the receiver 110 can also be a VNA, and the photoelectric conversion module is connected to the receiving end of the VNA.

[0039] Figure 2 Schematic diagram of the structure of the equivalent electromagnetic radiation effect test system during irradiation provided by the embodiment of the present invention. Figure 2As shown, an external signal source can be set to connect to the power amplifier module, and the power amplifier module is connected to the DC regulated power supply, and the power amplifier module is also connected to the antenna. The response of the cable terminal is actually a vector signal, but it is often the amplitude of the response that affects the device. Therefore, it is only necessary to monitor the response amplitude of the cable terminal in the future. This can be achieved using a signal source and a spectrum analyzer. The signal source is connected to the antenna, and the spectrum analyzer monitors the responses of the three groups of cable pairs respectively.

[0040] Figure 3 Schematic diagram of the structure of the equivalent electromagnetic radiation effect test system during current injection provided by the embodiment of the present invention. Figure 3 As shown, a dual-channel vector signal source is used to control the amplitude ratio and phase difference of two current injection probes, and a spectrum analyzer monitors the responses of three groups of cable pairs respectively.

[0041] Figure 4 It is a schematic diagram of the structure of the shielded multi-core interconnection system. Figure 4 As shown, the shielding layer of the cable is connected to the housing of the device, the height of the cable from the ground is h, and the length of the cable is L. The impedance of the device housing at both ends of the cable to ground is Z(e)L and Z(e)R respectively.

[0042] Figure 5 It is a schematic diagram of the structure of the cross section of the shielded multi-core wire. Figure 5 As shown, suppose there are n groups of cable pairs inside the shielded cable, and each group of cable pairs consists of two core wires, a and b. tnx It is the transfer impedance of the nth group of cables inside the shielded cable, from the core wire x to the shielding layer. From the outside to the inside, it is the insulating shell, the shielding layer, and the filling medium.

[0043] Figure 6 This is the equivalent circuit diagram of the double-end injection shielding layer. Figure 6 As shown in the figure, when the current injection probe is stuck on the shielded cable, it will couple a loading impedance Z on the cable shield. P and loading admittance Y P Since the width L of the current injection probe P is much smaller than L, so L P The current injection probe on the left is p1L away from the left end of the cable, and the coupling voltage is V S1 ; The current injection probe on the right is p2L away from the right end of the cable, and the coupling voltage is V S2 . Where p1, p2∈[0,1]. The characteristic impedance of the shielding layer is Z(e)C, and the propagation constant is γ (e) .

[0044] From the circuit calculation, we know that:

[0045]

[0046]

[0047] The above formulas (1) and (2) can be simplified as:

[0048] I (e) (0) = m1V S1 +m2V S2 (3)

[0049] I (e) (L) = m3V S1 +m4V S2 (4)

[0050] From the link parameter theory, we can get:

[0051]

[0052] The above formula (5) can be simplified as:

[0053]

[0054] Among them, m1~m8 and shielding layer propagation constant γ (e) , the loading impedance Z of the current injection probe P , loading admittance Y P , which is related to the position of the current injection probe and the ground impedance Z(e)0 and Z(e)L of the device casing at both ends of the cable.

[0055] The transmission line in the shield can be excited by a distributed voltage source V s ' i =Z tnx I S and the distributed current source I s ' i =-Y tnx V S Cylindrical conductors have a very good shielding effect on the electric field, so the effect of transfer admittance can be ignored. For braided shielded wires, considering that except for very large braid holes or large termination impedance of the shield to ground, the transfer admittance Y tnx It can be ignored. Under low-frequency conditions, the shielding effect of the electrostatic field of the braided mesh shielded multi-core cable is much better than the shielding effect of the magnetic field. However, as the frequency increases, both the electromagnetic and magnetic fields can pass through the braided mesh holes, and the effect of transfer admittance cannot be ignored at this time. However, since shielded multi-core cables mostly transmit low-frequency signals, high-frequency interference signals will be sharply attenuated during transmission after coupling to the internal core wires. Therefore, the influence of transfer admittance can be ignored in the study of shielded multi-core cables.

[0056] Then the source S of the transmission line in the cable 1nx , S 2nx for:

[0057]

[0058]

[0059] After integrating the above formula, we can get:

[0060]

[0061]

[0062] Among them, the expressions of formula (9) and (10) are specifically:

[0063]

[0064]

[0065] Figure 7 This is the internal transmission line circuit diagram of the shielded cable. Figure 7 As shown in the figure, in order to reduce external interference in actual projects, the circuit is made as balanced as possible. However, due to process reasons, the actual circuit cannot be completely balanced. The circuit of each cable pair is a simplified weakly unbalanced circuit. Therefore, the following circuit is constructed: Figure 7 The circuit shown, Z nx,y (x=a,b,ey=0,L) is the terminal impedance of the nth cable pair. The length of the internal core wire is L. Assuming that the medium in the shielding layer is the same, the propagation constant of the cable pair is γ (i) , Z(i)Cnx is the characteristic impedance of the nth group of cables to the core x (x = a, b). V na 、V nb and I na ,I nb They are the voltage and current of core wires a and b of the nth group of cables respectively.

[0066] From the BLT equation, we know that the voltage between the right end of the core wires a and b and the shielding layer of the nth cable pair is:

[0067]

[0068]

[0069] Wherein, the reflection coefficient is:

[0070]

[0071] Depend on It can be seen that the differential mode response of the right end of the nth group of cables is:

[0072]

[0073] Due to the linear relationship of field line coupling, the transmission line source S in the cable under irradiation conditions can be obtained 1nx , S 2nx They are Among them, a1, a2 and the incident angle of the radiation field, polarization direction, propagation constant γ (e) It is also related to the ground impedance Z(e)L and Z(e)R of the device casing at both ends of the cable.

[0074] Under the same injection conditions, the voltages between the right ends of the core wires a and b and the shielding layer of the nth cable pair are:

[0075]

[0076]

[0077] Then the differential mode response of the right end of the nth group of cables under irradiation conditions is:

[0078]

[0079] To achieve equal differential mode response of the device under injection and irradiation conditions, it is necessary to meet In this way, the excitation of the external port of the device under test is consistent under irradiation and injection conditions. Even if the impedance of the device under test undergoes nonlinear changes, the impedance change of the device under test under irradiation and injection conditions is consistent.

[0080] When (16) = (19), each cable pair will have V S1 and V S2 The equivalent correspondence relationship with the irradiation field strength E0(ω) is related to the impedance at both ends of the device under test. However, the impedance at both ends of each cable pair is not necessarily the same, which leads to different equivalent correspondences affected by the impedance at both ends. This undoubtedly increases the difficulty of the operation of the equivalent strong field irradiation test. In order to make each cable pair equivalent at the same time, when the source under irradiation and injection conditions is When:

[0081]

[0082] The above formula (20) shows that the two injection sources V S1 and V S2 The equivalent relationship between the irradiation field intensity E0(ω) and the incident angle, polarization direction, and loading impedance Z of the current injection probe is P , Loading admittance Y P , the location of the current injection probe, the propagation constant γ (e)And the impedance to ground Z(e)0 and Z(e)L of the device housing at both ends of the cable. The above parameters are relatively stable in engineering, so the two equivalent correspondences can be considered linear. In addition, these two correspondences are independent of the terminal impedance at both ends of each cable pair inside the shielded cable, which can make each cable pair equivalent at the same time with one injection. Establishing such an equivalent correspondence can also make the tested equipment at both ends of the shielded cable equivalent at the same time. This is of great significance in engineering.

[0083] Therefore, when conducting the shielded multi-core cable coupling equivalent strong field irradiation test, the following methods can be used for the test:

[0084] First, a low-field strength pre-test is carried out to find the equivalent correspondence between the two injection sources and the irradiation field strength. Then a high-field strength extrapolation test is carried out to extrapolate the two injection sources and the irradiation field strength by the same multiple. At this time, the differential mode response of the test equipment in the two cases is the same.

[0085] The strong field irradiation equivalent test method mentioned above has been studied before, but it is difficult to determine the equivalent correspondence between the two injection sources and the irradiation field strength in engineering. The two injection sources need to adjust both the amplitude and the phase. The following is an exploration of the determination method.

[0086] From formula (20), we can see that V S1 With V S2 The amplitude ratio and phase difference are the amplitude ratio and phase difference between the vector (a2n3-a1n4) and the vector (a1n2-a2n1).

[0087] Assume that under irradiation conditions, the DM response of the right end of cable pair 1 is R1, and the DM (Differential Mode) response of the right end of cable pair 2 is R2; S1 When the DM response of the right end of the cable pair is N1, the DM response of the right end of the cable pair 2 is N2; S2 The DM response at the right end of cable pair 1 is K1, and the DM response at the right end of cable pair 2 is K2. Therefore, it can be known that:

[0088]

[0089]

[0090] Then we can get:

[0091]

[0092] Let V S1 =V S2 =V'S, so we have:

[0093]

[0094]

[0095]

[0096]

[0097] And then:

[0098]

[0099]

[0100] It can be concluded that:

[0101]

[0102]

[0103] From the above calculation, we can know that V S1 and V S2 The amplitude ratio and phase difference of (K2R1-K1R2) and (N1R2-N2R1) are the amplitude ratio and phase difference of (K2R1-K1R2) and (N1R2-N2R1). In this way, the actual amount of injected source is determined based on the 6 monitored responses.

[0104] In some embodiments, the equivalent corresponding relationship is:

[0105]

[0106] V S1 is the coupling voltage of the first injection source, V S2 is the coupling voltage of the second injection source, and E0(ω) is the irradiation field intensity.

[0107] In the calculation process in the previous part, it was found that V can be determined by monitoring any 6 responses. S1 and V S2 The amplitude ratio and phase difference are feasible. The feasibility of this method is discussed below.

[0108] Assume that under irradiation conditions, the DM response of line pair n-1 is R3, and the DM response of the right end of line pair n is R4; S1 When the DM response of the right end of line pair n-1 is N3, the DM response of the right end of line pair n is N4; S2 When the DM response of line pair n-1 is K3, the DM response of line pair n is K4. Therefore, the following response calculation relationship is obtained.

[0109] (29)

[0111] At this time, V S1 and VS2 The amplitude ratio and phase difference of (K4R3-K3R4) and (N3R4-N4R3) are the amplitude ratio and phase difference of (K4R3-K3R4) and (N3R4-N4R3). Therefore, a1, a2, n1~n4 in the equation group are constant. Therefore, we have:

[0112]

[0113]

[0114] Among them, X=R,N,K. Then we have:

[0115] K4R3-K3R4=(AD-BC)(K2R1-K1R2) (36)

[0116] N3R4-N4R3=(AD-BC)(N1R2-N2R1) (37)

[0117] That is, the amplitude ratio and phase difference between (K4R3-K3R4) and (N4R3-N3R4) are consistent with the amplitude ratio and phase difference between (K2R1-K1R2) and (N1R2-N2R1).

[0118] This shows that the two groups of responses are determined under irradiation conditions, and the responses of the corresponding line pairs when each current probe is working are determined under injection conditions, so that V S1 and V S2 Amplitude ratio and phase difference.

[0119] In the process of obtaining the replication ratio and phase difference, a vector network analyzer is proposed for testing. Since the phase result measured by the device is the phase difference, the initial phase may affect the equivalent effect. Therefore, it is necessary to analyze formulas (30) and (31) again.

[0120] Assume that the output power of the vector network analyzer transmitter under irradiation conditions is The terminal responses of the two line pairs monitored by the receiving end are:

[0121]

[0122]

[0123] Assume that the output power signal of the transmitting end of the vector network analyzer under the condition of two injections is The responses of the two pairs of lines monitored by the receiving end are:

[0124]

[0125]

[0126]

[0127]

[0128] Substituting it into formulas (30) and (31), we can obtain:

[0129]

[0130] From the above derivation, it can be seen that the initial phase of the transmitter during the test has no effect on the acquisition of the equivalent injection source amplitude ratio and phase difference.

[0131] Based on the above theory, the electromagnetic radiation equivalent injection test of shielded multi-core cables can be realized according to the current injection method. Figure 7 1 is a flowchart of the implementation of the shielded multi-core wire coupled strong field electromagnetic radiation equivalent injection test method provided by the embodiment of the present invention. Figure 7 As shown, in some embodiments, a shielded multi-core wire coupled strong field electromagnetic radiation equivalent injection test method includes:

[0132] S810, irradiating a target cable and recording an irradiation response value of the target cable.

[0133] In some embodiments, the target cables are any two groups of cables in a shielded multi-core cable; each group of cables includes a first cable and a second cable; S810 includes: under a first preset field strength, using a radiation source to irradiate the parallel double wires, and the radio frequency transmission system records a first irradiation response value of the first cable pair and a second irradiation response value of the second cable pair.

[0134] In the embodiment of the present invention, the device under test needs to be disconnected before testing, and the response of two cable pairs is monitored by using the radio frequency transmission system. The first preset field strength can be any field strength value that the antenna can radiate, which can be set according to expert experience and is not limited here.

[0135] S820, insert a current injection probe into each of two ends of the target cable, connect the two current injection probes to a matching load and a signal source respectively, and record a current injection response value of the target cable.

[0136] In some embodiments, S820 may include: stopping the radiation source from irradiating, inserting a current injection probe at each end of the target cable, connecting the first current injection probe to a matching load, and connecting the second current injection probe to the transmitting end of the vector network analyzer, and then recording the first current injection response value of the first cable pair and the second current injection response value of the second cable pair; connecting the first current injection probe to a signal source, and connecting the second current injection probe to a matching load, and then recording the third current injection response value of the first cable pair and the fourth current injection response value of the second cable pair in the spectrum analyzer.

[0137] In the embodiment of the present invention, the two current injection probes can be connected to any signal source (the transmitting end of the vector network analyzer is also a type of signal source), and the output of the signal source connected to the current injection probes can be any value that the device can output, which can be set based on expert experience and is not limited here.

[0138] S830: Calculate the amplitude ratio and phase difference of the shielded multi-core cable according to the irradiation response value and the current injection response value.

[0139] In some embodiments, S830 may include:

[0140]

[0141]

[0142] Where J is the amplitude ratio, is the phase difference, (K2R1-K1R2) V Represents the amplitude of K2R1-K1R2, (N2R1-N1R2) V represents the amplitude of N2R1-N1R2, represents the phase of K2R1-K1R2, It represents the phase of N2R1-N1R2, R1 is the first irradiation response value, R2 is the second irradiation response value, N1 is the first current injection response value, N2 is the second current injection response value, K1 is the third current injection response value, and K2 is the fourth current injection response value.

[0143] S840, determining an equivalent injection excitation source based on the amplitude ratio and the phase difference.

[0144] In some embodiments, S840 may include: under a second preset field strength, using a radiation source to irradiate the parallel dual wires, and the RF transmission system records a first response value of the target cable; stopping the radiation source irradiation, inserting a current injection probe at each end of the target cable, connecting the first current injection probe to the first injection source, and connecting the second current injection probe to the second injection source; under the condition that the output powers of the first injection source and the second injection source satisfy the amplitude ratio and phase difference, making the response value of the target cable the same as the first response value, and obtaining an equivalent injection excitation source corresponding to the radiation field strength.

[0145] In the embodiment of the present invention, under the irradiation condition, a low power (corresponding to the second preset field strength E0) to irradiate the cable, and record the response of the cable in the two selected cable pairs. Then, under the injection condition, the amplitude ratio and phase difference calculated above are used to adjust the signals output by the two signal sources, gradually increasing the power by the same multiple, so that when V S1 The power is V S2 The power is When , the responses of the two cable pairs are the same as those under irradiation conditions.

[0146] S850, based on the equivalent injection excitation source, conducts high field strength extrapolation test to complete the electromagnetic radiation effect test process.

[0147] In some embodiments, S850 may include: connecting the device under test to a shielded multi-core cable, increasing the output power of the first injection source and the second injection source under the condition that the output power of the first injection source and the second injection source satisfies the amplitude ratio and phase difference, until the device under test responds, determining the electromagnetic radiation sensitivity threshold based on the equivalent correspondence between the radiation field strength and the injection excitation source, and completing the electromagnetic radiation effect test process.

[0148] In the embodiment of the present invention, the device under test is reconnected to the cable. The injected power is gradually increased. When V S1 The power is V S2 The power is Until the test equipment shows effect, that is, power The corresponding strong electric field strength is E1. By calculation, the electromagnetic radiation sensitivity threshold of the device under test is

[0149] A simulation calculation can be performed to verify the effectiveness of the method of the present invention, as follows:

[0150] Fig. 9 This is a schematic diagram of the structure of a shielded eight-core cable. Fig. 9 As shown, the simulation constructs a shielded eight-core cable, where two core wires form a pair of wires, with a total of 4 pairs, numbered I-IV. The shielded wire is 1m long and 0.1m from the ground.

[0151] In the construction of terminal impedance, the terminals at the left and right ends of each pair of shielded eight-core cables are set to an unbalanced state to simulate the poor impedance conditions of terminal equipment. Fig.10 It is an irradiation simulation model under low field strength conditions. Fig.11 This is a simulation model for injection under low field strength conditions. Fig.10 and Fig.11 As shown, probes P1 to P4 monitor the response of the left end of line pairs I to IV, and P5 to P8 monitor the response of the right end of line pairs I to IV. Under low field strength conditions, the irradiation field strength is 1 V / m.

[0152] In practice, for some commercially available current injection probes, the loading impedance Z coupled to the cable is P can be ignored. Secondly, ignoring the capacitance and radiation effects, the load admittance Y P Can be ignored.

[0153] Since the impedance at both ends of the cable changes nonlinearly under high field strength conditions, the terminal impedance can be reset under high field strength conditions to simulate nonlinear changes. In the simulation experiment, the terminal impedance settings for low and high field strengths are shown in Table 1 below:

[0154] Table 1 Line pair terminal impedance settings for low and high field strength conditions

[0155]

[0156] The plane wave field strength in the irradiation model is set to 1 V / m, and the injection model is set to V S1 =1nV, V S2 =0 and V S1 =0, V S2 =1nV. The response results are shown in Table 2.

[0157] Table 2 Response results

[0158]

[0159]

[0160] Taking 200MHz as an example, select P5 and P6 to continue the calculation, and we can get: R1=10 (-218.09387 / 20) e iπ(-75.320179 / 180) mV, R2=10 (-222.09194 / 20) e iπ(-162.94145 / 180) mV, K1 = 10 (-157.40157 / 20) e iπ(137.32132 / 180) mV, K2 = 10 (-157.02718 / 20) e iπ(125.92043 / 180) mV, N1 = 10 (-158.10347 / 20) e iπ(-63.511908 / 180) mV, N2 = 10 (-159.09446 / 20) e i π(-51.648782 / 180) mV.

[0161] Through calculation, we know that V S1 and V S2 The amplitude ratio is 1.00004, and the phase difference is -0.00135534°. The calculation results of other frequencies are shown in Table 3. In addition, the responses of P7 and P8 are also selected for calculation. It can be seen from Table 3 that V S1 Roughly the same as V S2 In the subsequent simulation, V S1 =V S2 This injection method.

[0162] Table 3 Amplitude ratio and phase difference calculated from simulation test

[0163]

[0164] Fig.12 is the result of low field strength simulation test. Fig.12 As shown, the two equivalent injection sources are set to V S1 =V S2 When the phase of the two injection sources is set to 0°, gradually increase the injection voltage to make the response of each line pair equal. Record the injection voltage value at this time.

[0165] It can be seen from the low-field strength simulation pre-test results that the response curves of each line pair under irradiation conditions and injection conditions are almost identical, indicating that the equivalent injection source obtained through the theoretical calculation in the second part is effective.

[0166] Fig.13 is the result of high field strength simulation test. Fig.13 As shown, the simulation process extrapolates 40dB, that is, the irradiation field strength is 100V / m, which is equivalent to Fig.12 The amplitude of the injected excitation source is increased by 100 times, and the phase remains unchanged. In order to simulate the nonlinear change of the impedance of the test equipment under strong field conditions, the impedance at both ends of the cable is set according to Table 1.

[0167] Depend on Fig.13 It can be seen that although the impedance of each pair of wires at both ends of the cable has changed, the response curves of each pair of wires under irradiation and injection conditions are basically the same, which shows that the equivalent injection source obtained under low field strength is effective, and also proves that the change of impedance at both ends of the cable will not affect the equivalent correspondence between the injection excitation source and the irradiation field strength.

[0168] It can be seen from the above simulation test results that the double-end injection method of the present invention can equivalently shield the strong field irradiation test of the multi-core coupling channel. The equivalent correspondence between the two injection excitation sources and the irradiation field strength is linear and has nothing to do with the terminal impedance, that is, this method is applicable to nonlinear systems. In addition, using two injection probes can make multiple groups of line pairs equivalent at the same time, which also has extremely high application value in engineering.

[0169] In order to verify the effectiveness of this method, a typical shielded six-core cable is selected to perform a through-type load test.

[0170] The test was carried out in an anechoic chamber. The shielded six-core interconnection system can be divided into three parts: the transmitting end, the shielded six-core cable, and the test end. The system is placed on a metal grounding plate. The shielded six-core cable is 1m long, and the shielding layer is connected to the aluminum shielding shell of the transmitting end and the test end respectively. In the left shielding box, three groups of wire pairs are connected to coaxial loads with different impedance values ​​to simulate the impedance matching of the system transmitting end. In order to monitor the response of the cable terminal, the cable terminal in the right shielding box is connected to through-type loads with different resistance values. Then each through-type load is terminated to the RF optical fiber transmission system. The impedance values ​​of the cable terminals are shown in Table 4.

[0171] Table 4 Impedance setting 1

[0172]

[0173] When determining the amplitude ratio and phase difference of the two injection sources, a vector network analyzer is used for testing. Port 2 of the vector network analyzer is used as the receiving end to monitor the response of each line pair, and is connected to the output ends of the three optoelectronic modules respectively. Port 1 is used as the transmitting end with an output power of 0dBm, and is connected to the antenna and two current injection probes respectively, representing three different excitation modes. It should be noted that when injecting current, both current injection probes need to be stuck on the cable, one current injection probe is connected to port 1 of the vector network, and the other current injection probe is terminated with a matching load. In order to facilitate monitoring the response, in the first excitation mode, port 1 of the vector network is connected to a microwave power amplifier with an amplification factor of 30dB. The microwave power amplifier is powered by a DC regulated power supply. Record the response (amplitude and phase) of each line pair under the three excitation modes at each frequency point. The response results are shown in Table 5.

[0174] Table 5 Response of each line pair terminal under three excitation modes

[0175]

[0176] According to the calculation method in Section 2, by selecting different line pairs, the amplitude ratio and phase difference corresponding to each frequency point can be obtained. Taking 70MHz as an example, under the three excitation modes, the responses of line pairs I, II, and III are respectively

[0177] Through calculation, we know that by selecting line pairs I and II, V S1 and V S2 The amplitude ratio is 1.14599, the phase difference is 37.8661°, and the I and III line pairs are selected for calculation. S1 and V S2 The amplitude ratio is 1.59107, and the phase difference is 25.975°. Select II and III line pairs for calculation, V S1 and V S2The amplitude ratio of is 1.83193, and the phase difference is 2.44405°. The amplitude ratios and phase differences of the other frequency points are shown in Table 6.

[0178] Table 6 Amplitude ratio and phase difference calculated at each frequency point

[0179]

[0180]

[0181] After the amplitude ratio and phase difference under irradiation conditions are determined, a low-field strength preliminary test is performed to obtain an equivalent injection source.

[0182] The response of the cable terminal is actually a vector signal, but it is the amplitude of the response that affects the device. Therefore, it is only necessary to monitor the amplitude of the response of the cable terminal in the future. This can be achieved using a signal source and a spectrum analyzer. The signal source is connected to the antenna, and the spectrum analyzer monitors the response of line pairs I, II, and III respectively.

[0183] Under injection conditions, a dual-channel vector signal source is used to control V S1 and V S2 Amplitude ratio and phase difference. In coherent mode, first adjust the phase of the output signal of the two channels according to the phase difference calculated in Table 6. Then, gradually increase the power of the output signal of the two channels according to the amplitude ratio calculated in Table 6. Since the goal of this method is to achieve the response of each line pair is equivalent to the irradiation condition at the same time, the error of each line pair is within the 3dB range, which means that the equivalent injection source has been obtained. Therefore, a certain line pair can be used as a reference line pair, and the power can be gradually increased so that the response of the line pair under the injection condition is the same as that under the irradiation condition. At this output power, record the response of the other two groups of line pairs to see if the error is within 3dB (for example, 50MHz). You can also compare the responses of the three line pairs as a whole, and adjust the injection power so that the response error of each line pair is less than 3dB (for example, 180MHz).

[0184] Based on the above equivalent ideas, the equivalent injection power obtained by the experiment is shown in the table. Injection 1 represents the V obtained by the response of line pairs I and II under injection conditions. S1 and V S2 Amplitude ratio and phase difference. Injection 2 and Injection 3 represent the calculation of line pairs I, III and line pairs II, III under injection conditions, respectively. As shown in Table 7, when the responses of each line pair under irradiation and injection conditions are the same, the power required for injection is much smaller than the power required for irradiation (average 30dB). In other words, the high current injection method is more efficient.

[0185] Table 7 Low field strength pre-test equivalent injection power

[0186]

[0187] Fig.14 It is the terminal response of the line to I under irradiation and three equivalent injection methods during the low field strength pre-experiment. Fig.15 It is the terminal response of line pair II under irradiation and three equivalent injection methods during low field strength pre-experiment. Fig.16 It is the terminal response of line pair III under irradiation and three equivalent injection modes during low field strength pre-experiment. Figure 14-16 It can be seen that by using these three equivalent injection methods to monitor the terminal responses of line pairs I, II, and III, and comparing them with the responses of line pairs I, II, and III under irradiation conditions, it can be seen that the responses of each line pair under the three equivalent injection methods are basically consistent with those under irradiation conditions. This shows that the V S1 and V S2 The amplitude ratio and phase difference can achieve the response of each line pair is equivalent to the response of the irradiation condition.

[0188] It should be noted that according to the theoretical derivation and the conclusion of the simulation test, the amplitude ratio and phase difference obtained by selecting different pairs of wires should be the same. However, the amplitude ratios and phase differences of each group obtained through the test are inconsistent. This is because the internal core wires of the shielded multi-core cable are not completely uniform in spatial distribution, and the core wires will be twisted during the processing to make the core wires firmly close together, resulting in the length of each core wire not being exactly the same. In addition, there is a systematic error in the phase of the response monitored by the vector network analyzer. During the calculation process, the phase has a great influence on the calculation results. Although the test obtained three groups of different amplitude ratios and phase differences, the use of these three different amplitude ratios and phase differences can achieve the simultaneous equivalence of each pair of wires. This is very important in engineering practice. For cables with more core wires, two groups of wire pairs that are easy to monitor the response can be selected to calculate the amplitude ratio and phase difference, and then a double-ended injection equivalent test can be performed.

[0189] The impedance value of each pair of wires at both ends of the cable is changed to simulate the nonlinear change of the impedance of the device under test under strong field conditions. The load change is shown in Table 8.

[0190] Table 8 Impedance Setting 2

[0191]

[0192] Fig.17 It is the terminal response of the line to I under irradiation and three equivalent injection modes in the high field strength extrapolation experiment; Fig.18 It is the terminal response of line pair II under irradiation and three equivalent injection modes in high field strength extrapolation experiment; Fig.19 It is the terminal response of line pair III under irradiation and three equivalent injection modes in high field strength extrapolation experiment. Figure 17-19 As shown in the above Figure 14-16 On the basis of the above, the output power of the irradiated and injected signal sources at this frequency point is amplified by 10dB respectively. At 150MHz, two identical power amplifier modules and coaxial connecting lines of the same length are connected to the signal source port to ensure that the amplitude ratio and phase difference of the output signal at the output end of the power amplifier module are the same as those shown in Table 6. The responses of line pairs I, II, and III under the two conditions are recorded respectively.

[0193] Although the impedance of each pair of wires at both ends of the cable has changed, the response curves of each pair of wires under irradiation and injection conditions are basically the same. After the high field strength extrapolation test, the error of each pair of wires is within the range of 3dB. This shows that the equivalent injection source obtained under low field strength is effective, and it also proves that the impedance change at both ends of the cable will not affect the equivalent correspondence between the injection excitation source and the irradiation field strength. Analyzing the possible causes of the error, transfer admittance exists in actual experiments, and it has an impact on the equivalent effect. And as the frequency increases, its impact will also increase. However, since the shielded cable transmits low-frequency signals, as the frequency increases, the signal loss will increase during the transmission process. Therefore, in the applicable frequency range of the shielded cable, the maximum error of each pair of wires is accepted within 3dB, and the impact of transfer admittance can be ignored.

[0194] The beneficial effects of the present invention are specifically as follows:

[0195] 1) Based on the equal differential mode response of each line pair of the equipment under irradiation and injection conditions, the equivalent correspondence between the injection excitation source and the irradiation field strength is established. Through theoretical derivation, it can be seen that the equivalent correspondence between the injection excitation source of each line pair and the irradiation field strength is linear and equal, and has nothing to do with the impedance parameters at both ends of the cable. The amplitude ratio and phase difference of the two current injection probes can be calculated through the response of any two sets of line pairs.

[0196] 2) An equivalent test method for the electromagnetic radiation effect of shielded multi-core coupled continuous wave strong field is proposed. This method can establish an equivalent correspondence between the injection excitation source and the irradiation field strength of all line pairs by simply monitoring the response of any two groups of line pairs. During the test, the operator only needs to select any two groups of line pairs for testing, and there is no need to perform an equivalent test on the response of each line pair. That is, when two groups of line pairs are equivalent, the remaining line pairs have also achieved equivalence. The test process and steps are simplified, and the test efficiency is improved.

[0197] 3) CST simulation test and through-load test verification were carried out. The test results show that even if the impedance at both ends of the cable changes nonlinearly under strong field conditions, the maximum error of each line pair is less than 3dB, which verifies the effectiveness of the proposed test method.

[0198] It should be understood that the order of execution of the steps in the above embodiment does not necessarily mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present invention.

[0199] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the protection scope of the present invention.

Claims

1. A shielded multi-core wire coupled strong field electromagnetic radiation equivalent injection test method, characterized in that: include: Irradiate the target cable and record the irradiation response value of the target cable; Insert a current injection probe at each end of the target cable, connect the two current injection probes to the matching load and the signal source respectively, and record the current injection response value of the target cable; Calculating the amplitude ratio and phase difference of the shielded multi-core cable according to the irradiation response value and the current injection response value; Determining an equivalent injection excitation source based on the amplitude ratio and the phase difference; Based on the equivalent injection excitation source, a high field strength extrapolation test is carried out to complete the electromagnetic radiation effect test process; The target cables are any two groups of cables in a shielded multi-core cable; Each set of cables includes a first cable and a second cable; Irradiate the target cable and record the irradiation response value of the target cable, including: Under a first preset field strength, a radiation source is used to irradiate the parallel double wires, and the radio frequency transmission system records a first irradiation response value of the first cable pair and a second irradiation response value of the second cable pair; Insert a current injection probe at each end of the target cable, connect the two current injection probes to the matching load and signal source respectively, and record the current injection response value of the target cable, including: Stop irradiation from the radiation source, insert a current injection probe at each end of the target cable, connect the first current injection probe to a matching load, and connect the second current injection probe to the transmitting end of the vector network analyzer, and then record a first current injection response value of the first cable pair and a second current injection response value of the second cable pair; After connecting the first current injection probe to the signal source and connecting the second current injection probe to the matching load, record the third current injection response value of the first cable pair and the fourth current injection response value of the second cable pair in the spectrum analyzer; Calculating the amplitude ratio and phase difference of the shielded multi-core cable according to the irradiation response value and the current injection response value, including: Wherein, J is the amplitude ratio, is the phase difference, (K2R1-K1R2) V Represents the amplitude of K2R1-K1R2, (N2R1-N1R2) V represents the amplitude of N2R1-N1R2, represents the phase of K2R1-K1R2, represents the phase of N2R1-N1R2, R1 is the first irradiation response value, R2 is the second irradiation response value, N1 is the first current injection response value, N2 is the second current injection response value, K1 is the third current injection response value, and K2 is the fourth current injection response value.

2. The shielded multi-core wire coupled strong field electromagnetic radiation equivalent injection test method according to claim 1 is characterized in that: Determining an equivalent injection excitation source based on the amplitude ratio and the phase difference as a standard includes: Under a second preset field strength, the parallel double wires are irradiated by a radiation source, and the radio frequency transmission system records a first response value of the target cable; Stop irradiation from the radiation source, insert a current injection probe into each end of the target cable, connect the first current injection probe to the first injection source, and connect the second current injection probe to the second injection source; Under the condition that the output powers of the first injection source and the second injection source satisfy the amplitude ratio and the phase difference, the response value of the target cable is made the same as the first response value, and an equivalent injection excitation source corresponding to the radiation field intensity is obtained.

3. The shielded multi-core wire coupled strong field electromagnetic radiation equivalent injection test method according to claim 1 is characterized in that: Based on the equivalent injection excitation source, a high field strength extrapolation test is carried out to complete the electromagnetic radiation effect test process, including: Connect the device under test to the shielded multi-core cable, and increase the output power of the first injection source and the second injection source under the condition that the output power of the first injection source and the second injection source satisfies the amplitude ratio and the phase difference until the device under test responds. Determine the electromagnetic radiation sensitivity threshold based on the equivalent correspondence between the radiation field intensity and the injection excitation source to complete the electromagnetic radiation effect test process.

4. The shielded multi-core wire coupled strong field electromagnetic radiation equivalent injection test method according to claim 1 is characterized in that: The equivalent corresponding relationship is: V S1 is the coupling voltage of the first injection source, V S2 is the coupling voltage of the second injection source, and E0(ω) is the irradiation field intensity.

5. An equivalent electromagnetic radiation effect test system, characterized in that: The shielded multi-core wire coupled strong field electromagnetic radiation equivalent injection test method as described in any one of claims 1 to 4 above is applied to the system, the system comprising: a coaxial load, a shielded multi-core wire cable, an antenna, a signal source, a first current injection probe, a second current injection probe, a matching load, a through load, a signal conversion module and a receiver; The coaxial load, the multi-core cable, the antenna, the first current injection probe, the second current injection probe, the matching load, and the through-type load are all arranged in the microwave darkroom; The first current injection probe and the second current injection probe are respectively arranged at two ends of the shielded multi-core cable; the coaxial load is connected to the first end of the shielded multi-core cable; the through-type load is connected to the second end of the shielded multi-core cable; and the signal conversion module is used to connect the through-type load arranged in the microwave darkroom with the receiver outside the microwave darkroom.

6. The equivalent electromagnetic radiation effect test system according to claim 5, characterized in that: When the system irradiates the shielded multi-core cable, the signal source and the antenna in the microwave darkroom form a radiation source, and the signal source outputs power corresponding to the first preset field strength or the second preset field strength to complete the irradiation process.

7. The equivalent electromagnetic radiation effect test system according to claim 6, characterized in that: When the system performs current injection on the shielded multi-core cable, the signal source is connected to the first current injection probe and the second current injection probe in the microwave darkroom; or the signal source is connected to the first current injection probe, and the second current injection probe is connected to the matching load; or the signal source is connected to a second current injection probe, and the first current injection probe is connected to the matching load; At the same time, the signal source outputs the first injection power or the second injection power to complete the current injection process.

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