Equivalent injection test method and system for strong field radiation effect of two-wire interconnection system

Abstract

The present invention provides a method and system for an equivalent injection test of a strong field radiation effect of a two-wire interconnection system. According to the first impedance of a parallel two-wire cable, the minimum number of turns of a current injection probe is determined; the number of turns is adjusted to be not less than the minimum number of turns; irradiation is performed according to a first preset field strength, and a first value of a spectrum analyzer is recorded; the radiation source irradiation is stopped, and after the probe is connected to a signal source, the injection power of the signal source is adjusted to determine a first injection power that is the same as the first value; according to the first preset field strength and the first injection power, a linear relationship between the signal source and the radiation source is determined; according to the second preset field strength and the linear relationship, a general high field strength extrapolation test is performed to complete the electromagnetic radiation effect test process; wherein the second preset field strength is greater than the first preset field strength. By adjusting the number of turns of the current injection probe, the impedance of the current injection probe is effectively reduced to a level far less than the impedance of the parallel two-wire cable, thereby avoiding the error of the equivalent test caused by the access of the current probe.

Description

Technical Field

[0001] The invention belongs to the technical field of electromagnetic radiation effects, and in particular relates to a method and system for an equivalent injection test of strong field radiation effects of a two-wire interconnection system. Background Art

[0002] In the future information battlefield, the rapid development of electromagnetic offensive weapons has brought the most severe challenges to weapons and equipment, integrated electronic information systems, etc. The cable coupling channel is the weak link in the electromagnetic protection of weapons and equipment. The peak field strength of the electromagnetic environment under the main beam of the ship transmitter in the 2.7-3.6GHz frequency band is as high as 27460V / m. However, the single full-level radiation test method under laboratory conditions has been unable to meet the technical requirements of the high-power RF electromagnetic radiation effect test of the cable coupling channel.

[0003] For this reason, strong field radiation effect equivalent test technology has received more and more attention from scientific researchers, such as the current injection method. Among the many current injection methods, large current injection technology is relatively more mature. However, there is still a gap in the application of this method in the research of strong field radiation effect equivalent test of the test equipment, and there is a problem of large test error. The strong field radiation effect equivalent test needs to be optimized. Summary of the invention

[0004] In view of this, the present invention provides a method and system for a strong field radiation effect equivalent injection test of a two-wire interconnection system, aiming to solve the problem of large test error in the prior art and the problem that the strong field radiation effect equivalent test needs to be optimized.

[0005] A first aspect of an embodiment of the present invention provides a method for equivalent injection testing of strong field radiation effects of a two-wire interconnection system, comprising:

[0006] Determine the minimum number of turns of the current injection probe according to the first impedance of the parallel two-wire cable;

[0007] Adjust the number of turns of the current injection probe to no less than the minimum number of turns;

[0008] According to a first preset field strength, using a radiation source to irradiate the parallel double lines, and recording a first value of the spectrum analyzer;

[0009] Stop irradiation from the radiation source, inject current into the probe and connect it to the signal source, then adjust the injection power of the signal source to determine a first injection power that is the same as the first value;

[0010] Determining a linear relationship between a signal source and a radiation source according to a first preset field strength and a first injection power;

[0011] A general high field strength extrapolation test is performed according to the second preset field strength and the linear relationship to complete the electromagnetic radiation effect test process; wherein the second preset field strength is greater than the first preset field strength.

[0012] A second aspect of an embodiment of the present invention provides an equivalent electromagnetic radiation effect test system, comprising: a display screen, a parallel two-wire cable, an antenna, a signal source, a current injection probe, a laser transmitting end, a signal conversion module and a receiver;

[0013] The display screen, parallel two-wire cable, antenna, current injection probe, and laser transmitting end are all set in a microwave darkroom;

[0014] The display screen is connected to the first end of the parallel two-wire cable; the laser transmitting end is connected to the second end of the parallel two-wire cable; and the signal conversion module is used to connect the first end of the parallel two-wire cable with a receiver outside the microwave darkroom.

[0015] The embodiment of the present invention provides a method and system for testing the equivalent injection of the strong field radiation effect of a two-wire interconnection system. According to the first impedance of the parallel two-wire cable, the minimum number of turns of the current injection probe is determined; the number of turns of the current injection probe is adjusted to be not less than the minimum number of turns; according to the first preset field strength, the parallel two-wire is irradiated with a radiation source, and the first value of the spectrum analyzer is recorded; the radiation source is stopped from irradiating, and after the current injection probe is connected to the signal source, the injection power of the signal source is adjusted to determine the first injection power with the same first value; according to the first preset field strength and the first injection power, the linear relationship between the signal source and the radiation source is determined; according to the second preset field strength and the linear relationship, a general high field strength extrapolation test is performed to complete the electromagnetic radiation effect test process; wherein the second preset field strength is greater than the first preset field strength. By adjusting the number of turns of the current injection probe, the impedance of the current injection probe is effectively reduced to a level far less than the impedance of the parallel two-wire cable, thereby avoiding the error of the equivalent test caused by the access of the current probe. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] 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.

[0017] Figure 1 It is a schematic diagram of the configuration of the strong field radiation effect equivalent test of the parallel double lines provided in the embodiment of the present invention;

[0018] Figure 2 It is a schematic diagram of a simplified model of parallel double lines;

[0019] Figure 3 is the equivalent circuit diagram of the current injection probe;

[0020] Figure 4 is the network model under injection conditions;

[0021] Figure 5 It is the network model under irradiation conditions;

[0022] Figure 6 It is a flow chart for realizing a method for testing the strong field radiation effect equivalent injection of a two-wire interconnection system provided by an embodiment of the present invention;

[0023] Figure 7 It is a curve graph showing the variation of the first impedance with the ground height under different conductor radii;

[0024] Figure 8 is a schematic diagram of the irradiation simulation model;

[0025] Fig. 9 It is a schematic diagram of the injection simulation model. DETAILED DESCRIPTION

[0026] 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.

[0027] Figure 1 FIG. 1 is a schematic diagram of the configuration of the strong field radiation effect equivalent test of the parallel double lines provided in the embodiment of the present invention. Figure 1 As shown, in some embodiments, the equivalent electromagnetic radiation effect test system includes: a display screen 11, a parallel two-wire cable 12, an antenna 13, a signal source 14, a current injection probe 15, a laser emitting end 16 and a receiving module; the receiving module includes a signal conversion module and a receiver.

[0028] The display screen 11, the parallel two-wire cable 12, the antenna 13, the current injection probe 15, and the laser emitting end 16 are all arranged in a microwave darkroom.

[0029] The display screen 11 is connected to the first end of the parallel two-wire cable 12; the laser emitting end 16 is connected to the second end of the parallel two-wire cable 12; and the signal conversion module is used for connecting the first end of the parallel two-wire cable 12 and the receiver outside the microwave darkroom.

[0030] The signal conversion module includes two photoelectric conversion modules, which are respectively connected to the laser transmitting end 16 and the receiver, and the two photoelectric conversion modules are connected via optical fiber. The receiver can be a test device, a spectrum analyzer, etc., which is not limited here.

[0031] In some embodiments, when irradiating a parallel two-wire cable, a signal source and an antenna in a microwave darkroom form a radiation source, and the signal source outputs a power corresponding to the first preset field strength or the second preset field strength to complete the irradiation process.

[0032] In some embodiments, when current is injected into a parallel two-wire cable, a signal source is connected to a current injection probe in a microwave darkroom, and the signal source outputs a first injection power or a second injection power to complete the current injection process.

[0033] In some embodiments, after the irradiation process is completed, a power amplifier and a directional coupler are sequentially connected between the signal source and the antenna or the current injection probe; a power meter is connected in parallel at both ends of the directional coupler;

[0034] The microwave darkroom is also equipped with a field strength meter and a camera for monitoring parallel two-wire cables. The field strength meter and the camera are connected to a monitor outside the microwave darkroom.

[0035] It is known from the electromagnetic field theory that the field line coupling process is linear, and the response process inside the EUT (Equipment under test) is nonlinear. If in some way, the excitation of the EUT external port is the same under irradiation and injection conditions, and the nonlinear changes of the internal devices of the EUT are the same, then the response of the EUT under the two conditions is also the same. Since the lumped source under irradiation conditions is obtained through the linear field line coupling process, the injection voltage source of the BCI (Bulk current injection) equivalent test can also be linearly extrapolated. At the same time, the injection excitation source is relatively easy to extrapolate in the BCI method. If the corresponding relationship between the irradiation field intensity and other parameters is re-established, such as the equivalent corresponding relationship between the irradiation field intensity and the injection excitation source, it is possible to make the BCI method equivalent to the strong field irradiation test.

[0036] To this end, the following measures are proposed Figure 1 The BCI method shown in the figure is an equivalent alternative to irradiation. Based on the equal response of the EUT, an attempt is made to establish an injection excitation voltage source V at low field strength. S The equivalent relationship with the irradiation field strength E0, that is, V S =k×E0, k is the equivalent corresponding relationship coefficient. Then the excitation source is extrapolated to carry out the electromagnetic radiation effect test of the strong field.

[0037] Figure 2 is a schematic diagram of a simplified model of parallel double lines. Figure 2As shown in the figure, the left end of the cable is the auxiliary device, and the right end is the device under test. The cable connecting the two is H from the ground and has a length of L. The current injection probe is stuck at any position on the cable, with the left end length L1 and the right end length L2. Assuming that the probe width is much smaller than the length of the parallel double wires, the width of the probe can be ignored. X (X=L,R) are the impedance network matrices of the auxiliary equipment and the equipment under test respectively. X (X=L,R) is the imbalance of the impedance of the left and right devices. GX (X=L,R) is the impedance of the equipment at both ends of the cable to ground, Z D The value is equal to the differential characteristic impedance of the two wires.

[0038] The two wires of the two-wire interconnection system form two ground loops with the earth respectively. In this way, the common-mode voltage generated by external interference on the cable will be converted into differential-mode voltage due to the imbalance of the terminal equipment. In actual engineering, differential-mode interference is the main factor that produces the effect of the test equipment. For the convenience of calculation, according to the definition of common and differential mode, all matrices are written in the form of modal domain:

[0039]

[0040] The EUT response to the injection condition is as follows:

[0041] Figure 3 This is the equivalent circuit diagram of the current injection probe. Figure 3 As shown, under injection conditions, the current probe is similar to a π-type circuit in the loop, V S is the excitation voltage source, Z P and Y P are the loading impedance and loading admittance respectively.

[0042] Through link parameter theory, the response calculation model of the device under test can be obtained. Figure 4 is the network model under injection conditions. Figure 4 As shown in the figure, the quantity of the thin line (transmission line) and the thick line (ground) represents the common mode quantity, and the quantity between the two is the differential mode quantity. V1 and I1 represent the voltage and current of wire 1 respectively, and V2 and I2 represent the voltage and current of wire 2 respectively. W (L) is the transmission matrix of the cable, T P is the probe modal domain matrix, F P is the source vector. Where V(0)=-Z L I(0),V(L)=Z R I(L). V=(V CM V DM ) T ,I=(I CM I DM ) TCM stands for common mode and DM stands for differential mode.

[0043]

[0044] F P =(V S -Y P V S ) T (4)

[0045] For a lossless transmission line, the phase shift constant β = 2π / λ, where λ is the wavelength. 2×2 is a 2nd-order unit matrix. C is the impedance matrix of the red and black lines, Z CM is the common mode characteristic impedance of the cable, Z DM is the differential characteristic impedance of the cable. P and Y P are the impedance and admittance matrices of the current probe, respectively. ZCM P and ZDM P are the common-mode impedance and differential-mode impedance of the probe coupled to the cable, respectively. YCMP and YDM P are the common-mode admittance and differential-mode admittance of the probe coupled to the cable, respectively.

[0046]

[0047] Therefore, the responses of the devices at both ends of the cable under injection conditions have the following relationship, where the superscript (i) indicates the injection conditions.

[0048]

[0049] The response of the equipment under test to the irradiation conditions is as follows:

[0050] Figure 5 is the network model under irradiation conditions. Figure 5 As shown in Figure 1, under irradiation conditions, irradiation interference will form a distributed source on the cable. Since the focus is on the response of the cable terminal, the distributed source vector on the cable can be converted into a lumped source vector V at both ends of the cable.

[0051] In the modal domain, the lumped source vector V is:

[0052] V=(V 0) T (9)

[0053] Since the field line coupling process is a linear process, it can be simplified as:

[0054] V SL =a1E0 V SR =a2E0 (10)

[0055] Therefore, the response of the devices at both ends of the cable under irradiation conditions has the following relationship, where the superscript (r) represents the irradiation conditions.

[0056]

[0057] In the equivalent method proposed earlier, the key to the theoretical derivation is that the coefficient matrix before the response matrix of the equipment under test is equal, that is, under two conditions, The coefficient matrix Τ W (L2) P Τ W (L1) is the same. In the above derivation process, under irradiation conditions The coefficient matrix is ​​T W (L1+L2); under injection conditions The coefficient matrix is ​​T W (L2) P Τ W (L1).

[0058] Under ideal conditions, the positions of the two-core cables relative to the current probe are the same. Analyzing the coupling mechanism, in the differential mode loop, since the differential mode currents of the two cores are of the same magnitude and opposite in direction, the differential mode impedance and differential mode admittance induced by the current probe and the two cores cancel each other out. In other words, the differential mode loop under injection conditions does not contain the relevant parameters of the current injection probe. The expressions of differential mode impedance and differential mode admittance from the inductive coupling of the current probe to the cable can also assist in the derivation. The values ​​of the two are very small and can be ignored. That is, Therefore, we can get:

[0059]

[0060] Substituting the above formula, we can get:

[0061]

[0062] In the calculation process, if strict equivalence is to be achieved and the equivalent correspondence relationship is independent of the EUT, it can be known through calculation that Τ W (L2) P Τ W (L1) = Τ W (L1+L2).

[0063] By observation, we can see that the matrix T W (L2) P Τ W (L1) and Τ W The order of magnitude of the elements in (L1+L2) that are not equal to 0 is the same. The different elements in the two matrices have an extra coefficient. If you can control Then it is possible to achieve W (L2) PΤ W (L1)≈Τ W (L1+L2).

[0064] Figure 6 1 is a flow chart of the implementation of the strong field radiation effect equivalent injection test method for a two-wire interconnection system provided by an embodiment of the present invention. Figure 6 As shown, in some embodiments, a method for equivalent injection testing of strong field radiation effect of a two-wire interconnection system includes:

[0065] S610, determining a minimum number of turns of a current injection probe according to a first impedance of the parallel two-wire cable;

[0066] S620, adjusting the number of turns of the current injection probe to be no less than a minimum number of turns;

[0067] S630, irradiating the parallel double lines using a radiation source according to a first preset field strength, and recording a first value of the spectrum analyzer;

[0068] S640, stopping the radiation source from irradiating, injecting a current into the probe and connecting it to the signal source, adjusting the injection power of the signal source, and determining a first injection power that is the same as the first value;

[0069] S650, determining a linear relationship between the signal source and the radiation source according to the first preset field strength and the first injection power;

[0070] S660, performing a general high field strength extrapolation test according to the second preset field strength and the linear relationship to complete the electromagnetic radiation effect test process; wherein the second preset field strength is greater than the first preset field strength.

[0071] Among them, S630-S660 are steps used in conventional irradiation effect equivalent test. On this basis, the present invention adds S610 and S620 to determine the number of turns of the primary winding of the current injection probe. The change of the number of turns will change the impedance of the current injection probe, thereby controlling Realization W (L2) P Τ W (L1)≈Τ W (L1+L2), so after adjusting the number of turns of the primary winding of the current injection probe, no correction steps are required to achieve equivalence and complete the radiation effect equivalent test.

[0072] In some embodiments, S610 includes: calculating a target second impedance according to the first impedance; and determining a minimum number of turns of the current injection probe according to the target second impedance.

[0073] In some embodiments, calculating the target second impedance according to the first impedance includes:

[0074]

[0075] Among them, Z CM is the first impedance, is the target second impedance.

[0076] In the embodiment of the present invention, the value range of the target second impedance can be calculated by the above formula, and the target second impedance is any value within the range.

[0077]

[0078] From the above formula, we can see that Z CM The value of depends on the structure of the cable itself and its height from the ground. Figure 7 It is a curve graph showing the change of the first impedance with the ground height under different wire radius. Figure 7 As shown, s = 3r w ,For general transmission cables, even at 5 cm above the ground, the ZCMP is on the order of 150Ω.

[0079] As a stable way to transmit energy, it is very difficult to change the specific property parameters of cables. CM The order of magnitude is in the range of 100Ω to 400Ω. However, the impedance value of current injection probes on the market today is mostly around 50Ω. If you use a current injection probe on the market, It is difficult to achieve. To achieve equivalence, a current injection probe specially designed for equivalent strong field irradiation test is required.

[0080] In some embodiments, determining the minimum number of turns of the current injection probe according to the target second impedance includes:

[0081]

[0082] in, is the target second impedance, Z′ P is the first part of the target second impedance, The second part of the target second impedance, r core is the inner diameter of the current probe, s is the wire spacing, r w Conductor radius, L P is the width of the probe, P(f) is the composite permeability of the probe ferrite core that varies with frequency, N1 is the minimum number of turns of current injected into the probe, and Z TH It is the equivalent input internal resistance after the signal source is connected to the probe.

[0083] In the embodiment of the present invention, it can be estimated that in the frequency range below 1 GHz, the second part of formula (17) is much smaller than Z CM, so as long as Z′ is guaranteed P Also much smaller than Z CM From formula (18), it can be seen that increasing the number of turns N1 of the primary winding coil of the current injection probe is the simplest way to reduce the ZCMP value.

[0084] For example, when the number of winding turns N1=4, the value of ZCMP will be 1 / 16 of that when N1=1. For example, the ZCMP value of the BCI probe F-130A coupled to the cable with a single-turn excitation winding is close to a flat 50Ω level in the high-frequency region. Therefore, by approximate calculation, when N1≥2, It is possible to achieve. On the other hand, ZCM P< <Z CM When the impedance presented by ZCMP on the cable is negligible.

[0085] From the above analysis, it can be seen that in order to realize the BCI equivalent replacement of strong field irradiation test for nonlinear test equipment in parallel two-wire coupling channel, it is necessary to design a special current injection probe.

[0086] The current probe can be optimized by increasing the number of turns of the current probe coil and selecting ferrite materials with high Curie temperature and low magnetic saturation. This ensures that the relevant parameters of the current probe remain relatively stable under high power conditions. The hardware support for strong field extrapolation can be guaranteed.

[0087] In some embodiments, S650 includes:

[0088]

[0089] Among them, k is the equivalent correspondence coefficient, V S0 is the first injection power, and E0 is the first preset field strength.

[0090] In the embodiment of the present invention, the above formula is a linear relationship, and the key to the linear relationship is to determine the equivalent corresponding relationship coefficient k.

[0091] In some embodiments, S660 includes: under a second preset field strength, using a radiation source to irradiate the parallel two lines, and recording a second value of the spectrum analyzer; calculating a second injection power based on a linear relationship; stopping the radiation source from irradiating, injecting current into the probe and connecting it to the signal source and then inserting it into the cable, adjusting the injection power of the signal source to the second injection power, and recording a third value of the spectrum analyzer; determining the differential mode response of the high field strength extrapolation test based on the second and third values, and completing the electromagnetic radiation effect test process.

[0092] In some embodiments, the differential mode response of the high field strength extrapolation test is determined based on the second value and the third value, including: calculating the difference between the second value and the third value to obtain the differential mode voltage; if the differential mode voltage is less than a preset value, the linear relationship is valid, and the electromagnetic radiation effect test process is completed.

[0093] In an embodiment of the present invention, the second preset field strength may be one or more, which is not limited here. For example, if two high field strength extrapolation tests are required, the response size in the two cases can be recorded by increasing 20 dB each time on the basis of the first preset field strength, observing the change of the response of the right-end through-type load during irradiation excitation and injection excitation with the nonlinear change of the impedance of the right-end EUT after the field strength extrapolation, and recording the differential mode response of the right-end EUT under the two excitation conditions. This method conducts two field strength extrapolation experiments, each time increasing by 20 dB, and each time changing the impedance of the right-end EUT. It is worth noting that in the extrapolation test, the impedance value of the right-end through-type load is also changed to simulate the nonlinear change of the EUT impedance under strong field conditions. Among them, the second preset field strength multiplied by the equivalent corresponding relationship coefficient k in the linear relationship is the second injection power.

[0094] The purpose of equivalence is to make the response of the device under irradiation and injection conditions equal, that is, V (r) (L) = V (i) (L). By solving equations (6) and (9) simultaneously, we can obtain the equivalent corresponding relationship between the injected excitation voltage source and the irradiation field intensity:

[0095]

[0096] in,

[0097]

[0098] Among them, H PL is the transfer function of the parallel two-wire coupling channel. This transfer function is related to the impedance characteristics of the cables connected by the two-wire interconnection system, the impedance parameters of the current injection probe and the left-end transmitter, and has nothing to do with the impedance parameters of the EUT at the right end of the cable. This shows that regardless of whether the EUT is a nonlinear system, the impedance parameters of the EUT do not affect the equivalent correspondence. Therefore, the cable terminal response can be monitored by removing the EUT at the cable terminal or by connecting a parallel clamp. Then adjust the signal source so that the response of the cable terminal under irradiation and injection conditions is equal, thus successfully obtaining the equivalent injection source. In engineering, the transmitter is usually in a low-resistance state, and the impedance parameters are often stable. Therefore, the equivalent correspondence relationship H PLIt is linear, which provides a basis for linear extrapolation of the injection excitation source. After establishing the equivalent correspondence under low field strength, the effect test can be directly performed on the EUT. The interference threshold of the EUT under injection conditions can be converted to the interference threshold of the EUT under irradiation conditions.

[0099] In summary, the three problems faced by the single-ended injection equivalent strong field irradiation test method (EUT is a nonlinear system that brings large errors, how to obtain an equivalent injection source, and whether the equivalent injection source can be linearly extrapolated) can be solved in theory. Therefore, in engineering, the method of obtaining the equivalent corresponding relationship between the injection excitation voltage source and the irradiation field strength under low field strength conditions and linearly extrapolating the injection excitation source under high field strength can make the BCI equivalent strong field irradiation effect test.

[0100] To carry out strong field radiation equivalence test, it is first necessary to obtain the response of cable terminals under both radiation and injection conditions.

[0101] There are many types of EUTs. If the EUT has an output port that can be directly monitored, the spectrum analyzer can be connected to the output port to directly monitor the response. However, most EUTs do not have direct output ports, and it is not easy to measure the response of the cable terminal. This increases the difficulty of establishing an equivalent correspondence between the injection excitation source and the irradiated field strength through equal response. Since the relationship between the injection source and the radiated field strength has nothing to do with the impedance of the EUT. This means that no matter what device is connected to the cable terminal, it does not affect H PL Therefore, in actual projects, the cable can be disconnected to directly test the terminal response of the cable. Alternatively, the EUT can be turned off and a pair of wires can be connected in parallel at the cable terminal.

[0102] Next, we need to obtain the equivalent injection excitation voltage source. The purpose of the equivalent test is always to make the monitoring response under irradiation and injection conditions equal. In order to simplify the operation steps and calculation process, in the low field strength pre-test, the output power of the signal source can be directly adjusted to make the response of the cable terminal under irradiation and injection conditions equal. In this way, the signal source power under the injection condition is the equivalent excitation source converted by the transfer function, and the equivalent corresponding relationship is established.

[0103] After obtaining the equivalent injection excitation source, an extrapolation test is required. Regardless of low or high field strength, the corresponding relationship between the injection excitation voltage source and the irradiation field strength is always linear. This makes the irradiation and injection excitation at the external port of the EUT consistent in high field strength. The impedance changes of the EUT are also consistent, and the response is also consistent.

[0104] The linear equivalent correspondence is very important, which means that linear extrapolation can be performed during the equivalent field irradiation test. This is also the reason why the equivalent correspondence established under low field strength conditions is used. High field strength conditions are not easy to achieve, but low field strength conditions are obviously very easy to achieve.

[0105] Based on the above theoretical derivation and implementation technology proposed, the cable is now simulated and tested. Figure 8 It is a schematic diagram of the irradiation simulation model. Fig. 9 is a schematic diagram of the injection simulation model. Figure 8 and Fig. 9 As shown in the figure, a 5m×0.6m PEC sheet is set in space, and 300mm above the sheet, there are parallel double wires with a length of 2m and a line spacing of 3.5mm. The cable type is two single wires, and a simulation model is constructed.

[0106] Under irradiation conditions, a horizontally polarized radiation field of 1V / m is applied, and a linear extrapolation of 12dB is performed. Since the current injection probe of the test method completely inserts the parallel double wires, the common mode excitation source is formed between the two core wires and the ground respectively. Therefore, the two core wires on the left side of the EUT in the injection model are respectively applied with a collective common mode voltage excitation source. In order to simulate the unbalanced impedance of the equipment at both ends of the parallel double wires, the capacitance to ground of the 50Ω on the left end is set to 3pF and 2pF respectively, so that the unbalance degree δ on the left end is L =0.2; Similarly, the capacitance to ground at the right end is set to 3pF and 7pF respectively, so the unbalance degree of the right end is δ R = 0.4. A voltage probe is applied between the two single wires to monitor the interference voltage.

[0107] In the low and high field strength simulation tests, the impedance at the right end is always the impedance value of the EUT. The nonlinear change of the impedance of the EUT under strong field conditions is simulated by changing the impedance value (25Ω, 50Ω, 150Ω) connected in parallel to the right end of the EUT in the extrapolation simulation.

[0108] because Therefore, the impedance of the current probe coupled to the cable in the injection model can be ignored.

[0109] During the simulation process, the equivalent injection excitation source acquisition technology is first simulated. In the irradiation model, under the action of the 1V / m radiation field, the differential mode response of the right-end test device is V(r)0(dBmV). Then, in the injection model, the power Pi of the common-mode voltage source is adjusted so that the differential mode response of the right-end test device V(i)0(dBmV)=V(r)0(dBmV). At this point, the equivalent injection excitation source has been acquired.

[0110] Then, the equivalent injection excitation source extrapolation technology is simulated. In the irradiation and injection models, the impedance value of the device under test on the right side is changed to another identical value to simulate the nonlinear change of the impedance of the device under test under strong field conditions. In the irradiation model, the radiation field power is increased by 12dB, and the differential mode response V(r)1(dBmV) of the device under test on the right side is recorded at this time. In the injection model, Pi is increased by 12dB, and the differential mode response V(i)1(dBmV) of the device under test on the right side is recorded at this time. Calculate the error error(dB)=|V(i)1-V(r)1|.

[0111] The accuracy of the response results of the simulation calculation is 6 decimal places. For a more intuitive observation of the results, the first 4 decimal places are taken. The simulation results are shown in Table 1:

[0112] Table 1 Parallel double-line simulation test results

[0113]

[0114] It can be seen from the above simulation results that the implementation technology proposed in Chapter 3 can be equivalent to the strong field irradiation test. The bold data in the table are the responses of the equipment under test under the extrapolated test conditions. By calculating the responses under irradiation and injection conditions, the error is very small and almost negligible. The reason for the error may be that during the low-field pre-simulation process, the software can calculate the response (dBmV) with an accuracy of 6 decimal places, which makes it possible to establish an equivalent correspondence. The response of the EUT under injection and irradiation conditions is not completely equal. This may amplify the error after linear extrapolation. Even in this case, the error is still very small, which shows that the BCI method can be used for strong field irradiation equivalent testing of cable coupling channels in two-wire interconnection systems.

[0115] After the above simulation test is completed, the present invention is also based on Figure 1 The structure shown in the figure was actually tested. The impedance parameters of commercial current injection probes will drop sharply in linearity as the injection power increases. From theoretical derivation, it can be known that in order to realize the BCI equivalent strong field irradiation test of parallel two-wire coupled channels. The current injection probe needs to meet two conditions: the number of coil turns is greater than 1 and it has high linearity under high power conditions. In this test, a current injection probe with 4 turns and an insertion loss of less than 1dB with injection power was used. Therefore, the current injection probe used in the verification test has an insertion loss of less than 0.3dB with injection power.

[0116] During the test, a low field strength pre-test is first performed. Since the equivalent correspondence between the injected excitation voltage source Vs and the irradiated field strength E has nothing to do with the EUT, the power supply can be turned off under low field strength conditions to monitor the terminal response by connecting a parallel clamp. Turn off the power supply of the sensor to prevent damage to the electro-optical module. Record the response P1 (dBm) of the cable terminal under irradiation conditions, when the field strength is E0 (V / m). Then, under injection conditions, adjust the power of the signal source so that the response P2 = P1 of the cable terminal, and record the forward power P(i)0 (dBm) at this time.

[0117] Then carry out the high field strength extrapolation test, remove the parallel clips and turn on the power. Adjust the injection power until the reading on the sensor screen stops. Then reduce the injection power by 1 dB and increase the injection power in steps of 0.3 dB until the reading on the screen stops again. Record the forward power P(i)1 at this time. Then the power gain k1| dB =P(i)1-P(i)0. Since the equivalent corresponding relationship between the injection excitation voltage source Vs and the irradiation field strength E established in formula (24) is linear, the critical interference field strength corresponding to the irradiation at this frequency is Increase the power under irradiation conditions, and make the display stop again according to the method of injection, and record the field strength E2 (V / m) at this time. Error deta| dB =20logE2 / E1.

[0118] The test results are shown in Table 2.

[0119] Table 2 Laser ranging sensor effect test results

[0120]

[0121]

[0122] In each frequency point test, the first and second rows represent the low field strength response test and the high field strength effect test, respectively. Under low field strength conditions, the responses of the cable terminals are equal, indicating that the equivalent injection source has been successfully obtained. The error of the high field strength effect test is less than 3dB, which meets the requirements of the project. It is worth noting that as long as the external excitation of irradiation and injection is consistent, the nonlinear change of the EUT impedance under the two conditions is consistent. The acquisition of the equivalent correspondence under low field strength does not involve the display screen, which shows that even if the EUT is a nonlinear device, this method is still effective.

[0123] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0124] 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 method for equivalent injection test of strong field radiation effect of a two-wire interconnection system, characterized in that: include: Determine the minimum number of turns of the current injection probe according to the first impedance of the parallel two-wire cable; Adjusting the number of turns of the current injection probe to be no less than the minimum number of turns; According to a first preset field strength, using a radiation source to irradiate the parallel double lines, and recording a first value of the spectrum analyzer; Stop irradiation from the radiation source, inject a current into the probe and connect it to the signal source, then adjust the injection power of the signal source to determine a first injection power that is the same as the first value; Determining a linear relationship between a signal source and a radiation source according to the first preset field strength and the first injection power; Perform a general high field strength extrapolation test according to the second preset field strength and the linear relationship to complete the electromagnetic radiation effect test process; wherein the second preset field strength is greater than the first preset field strength; The step of determining the minimum number of turns of the current injection probe according to the first impedance of the parallel two-wire cable comprises: Calculating a target second impedance based on the first impedance; Determining a minimum number of turns of a current injection probe according to the target second impedance; Determining a minimum number of turns of a current injection probe according to the target second impedance includes: in, is the target second impedance, Z P ' is the first part of the target second impedance, The second portion of the target second impedance, r core is the inner diameter of the current probe, s is the wire spacing, r w Conductor radius, L P is the width of the probe, P(f) is the composite permeability of the probe ferrite core that varies with frequency, N1 is the minimum number of turns of current injected into the probe, and Z TH It is the equivalent input internal resistance after the signal source is connected to the probe.

2. The method for equivalent injection test of strong field radiation effect of two-wire interconnection system according to claim 1 is characterized in that: Calculating a target second impedance according to the first impedance includes: Among them, Z CM is the first impedance, is the target second impedance.

3. The method for equivalent injection test of strong field radiation effect of two-wire interconnection system according to claim 1 is characterized in that: Determining a linear relationship between a signal source and a radiation source according to the first preset field strength and the first injection power includes: Among them, k is the equivalent correspondence coefficient, V S0 is the first injection power, and E0 is the first preset field strength.

4. The method for equivalent injection test of strong field radiation effect of two-wire interconnection system according to claim 1 is characterized in that: A general high field strength extrapolation test is performed according to the linear relationship to complete the electromagnetic radiation effect test process, including: Under a second preset field strength, using a radiation source to irradiate the parallel double lines, and recording a second value of the spectrum analyzer; Calculating a second injection power according to the linear relationship; Stop irradiation from the radiation source, connect the current injection probe to the signal source and then insert the cable, adjust the injection power of the signal source to the second injection power, and record the third value of the spectrum analyzer; According to the second value and the third value, the differential mode response of the high field strength extrapolation test is determined to complete the electromagnetic radiation effect test process.

5. The method for equivalent injection test of strong field radiation effect of two-wire interconnection system according to claim 4 is characterized in that: Determining a differential mode response of a high field strength extrapolation test according to the second value and the third value includes: Calculate the difference between the second value and the third value to obtain a differential mode voltage; If the differential mode voltage is less than the preset value, the linear relationship is valid, and the electromagnetic radiation effect test process is completed.

6. An equivalent electromagnetic radiation effect test system, characterized in that: The strong field radiation effect equivalent injection test method of the two-wire interconnection system as described in any one of claims 1 to 5 above is applied to the system, the system comprising: a display screen, a parallel two-wire cable, an antenna, a signal source, a current injection probe, a laser transmitting end, a signal conversion module and a receiver; The display screen, parallel two-wire cable, antenna, current injection probe, and laser transmitting end are all arranged in a microwave darkroom; The display screen is connected to the first end of the parallel two-wire cable; the laser transmitting end is connected to the second end of the parallel two-wire cable; and the signal conversion module is used to connect the first end of the parallel two-wire cable with a receiver outside the microwave darkroom.

7. The equivalent electromagnetic radiation effect test system according to claim 6, characterized in that: When the system irradiates the parallel two-wire 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; When the system performs current injection on the parallel two-wire cable, the signal source is connected to the current injection probe in the microwave darkroom, and the signal source outputs the first injection power or the second injection power to complete the current injection process.

8. The equivalent electromagnetic radiation effect test system according to claim 7, characterized in that: After the irradiation process is completed, a power amplifier and a directional coupler are connected in sequence between the signal source and the antenna or the current injection probe; a power meter is connected in parallel at both ends of the directional coupler; The microwave darkroom is also provided with a field intensity meter and a camera for monitoring the parallel two-wire cables, and the field intensity meter and the camera are connected to a monitor outside the microwave darkroom.

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