Magnetic field probe for electromagnetic pulse measurement and electromagnetic pulse measurement method

Abstract

The present invention relates to an electromagnetic pulse measurement device and method, and specifically to a magnetic field probe and electromagnetic pulse measurement method for electromagnetic pulse measurement. The method solves the technical problems that existing magnetic field probes are susceptible to interference, the differential signal output after integration has errors with the original signal, the secondary numerical integration calculation is inconvenient, or the method is not suitable for measuring fast-front pulse magnetic field signals. The magnetic field probe for electromagnetic pulse measurement provided by the present invention includes a coaxial cable with a gap, a shielding shell, and an integration circuit, a high input impedance amplifier circuit, and an electro-optical conversion circuit arranged in the shielding shell and connected in sequence. The output signal of the magnetic field probe is the original signal of the magnetic field waveform, avoiding the need for numerical integration to restore the magnetic field waveform to be measured in differential measurement. The coaxial cable with a gap is semicircular and includes an inner core and a shielding layer. An annular gap is provided circumferentially on the upper surface of the shielding layer. The two ends of the inner core are respectively connected to the integration circuit and a load resistor, and the method has a strong ability to resist electric field interference.

Description

Technical Field

[0001] The present invention relates to an electromagnetic pulse measuring device and method, and in particular to a magnetic field probe for electromagnetic pulse measurement and an electromagnetic pulse measuring method. Background Art

[0002] The interference of high-altitude electromagnetic pulses or ultra-wideband electromagnetic pulses on electronic equipment cannot be ignored. Therefore, it is necessary to monitor the electric field and magnetic field energy of the electromagnetic pulses when conducting strong electromagnetic pulse effect tests.

[0003] Electromagnetic pulse monitoring typically uses a coil as a magnetic field probe. The greater the coil's inductance, the worse its high-frequency performance. When the coil's terminal load is much smaller than the coil's own inductance, the voltage waveform across the load matches the measured magnetic field waveform. When the coil's terminal load is much larger than the coil's own inductance, the voltage waveform across the load is a differential form of the measured magnetic field waveform. The rise time of waveforms such as high-altitude electromagnetic pulses is in the nanosecond range, and the corresponding high-frequency components can reach over hundreds of MHz. To ensure the high-frequency performance of the magnetic field probe, the coil's own inductance must be very low. Only when the coil's load is in the micro-ohm range does the load voltage closely match the magnetic field waveform. However, too low a coil load greatly complicates back-end signal acquisition. Therefore, increasing the resistance of the coil's terminal load can obtain the differential waveform of the magnetic field, and numerical integration can be used to recover the true magnetic field signal. However, magnetic field probes employing this method are susceptible to interference from the pulsed electric field, resulting in discrepancies between the integrated signal and the true magnetic field signal. Furthermore, the secondary numerical integration process introduces certain inconveniences for engineering testers.

[0004] Chinese patent publication number CN214845500U discloses a self-integrating time-domain magnetic field probe. Its coil is a winding coil with a large inductance, making it incapable of measuring fast-front magnetic field signals such as high-altitude electromagnetic pulses. Chinese patent publication number CN203572948U discloses a high-frequency magnetic field probe, and Chinese patent publication number CN 107607888A discloses a three-dimensional transient magnetic field measurement system. Both utilize a notched shielded ring antenna. The inner core of each shielding ring is connected to the shielding layer at one end, resulting in impedance mismatch at the core terminal. This causes the shielded ring antenna to reflect and oscillate high-frequency signals, and the associated matching circuit is also unsuitable for measuring fast-front pulse magnetic field signals.

[0005] Chinese patent publication number CN115032575A discloses a passive differential magnetic field probe based on a differential dual-loop and integrated balun structure. Chinese patent publication number CN113702878A discloses a miniaturized active differential magnetic field probe with high common-mode rejection ratio and high sensitivity. These two designs are based on a dual-loop differential method and can eliminate electric field interference, but their output signals are still differential forms of the magnetic field waveform to be measured, which are more suitable for near-field magnetic field scanning tests. When measuring time-domain electromagnetic pulse magnetic field signals, the measurement data still needs to be numerically integrated, and the signal transmission link of the coaxial cable is susceptible to secondary interference from the electromagnetic pulse. Summary of the Invention

[0006] The purpose of the present invention is to solve the technical problems that the existing magnetic field probe is susceptible to interference, the output differential form signal has errors with the original signal after integration, the secondary numerical integration calculation is inconvenient, or it is not suitable for measuring fast-front pulse magnetic field signals, and to provide a magnetic field probe and electromagnetic pulse measurement method for electromagnetic pulse measurement.

[0007] To achieve the above object, the technical solution adopted by the present invention is:

[0008] A magnetic field probe for electromagnetic pulse measurement, which is special in that it includes a coaxial cable with a gap, a shielding shell, and an integration circuit, a high input impedance amplifier circuit, an electro-optical conversion circuit and a load resistor arranged in the shielding shell;

[0009] The shielding shell is provided with two connection ports for connecting the coaxial cables with gaps;

[0010] The gapped coaxial cable is semicircular and includes an inner core and a shielding layer wrapped around the inner core. The shielding layer is provided with an annular gap along the circumference. The two ends of the inner core extend into the interior of the shielding shell through two connecting ports and are respectively connected to the input end of the integration circuit and one end of the load resistor. The other end of the load resistor is grounded.

[0011] The gapped coaxial cable is used to sense a magnetic field differential signal;

[0012] The integration circuit is used to restore the magnetic field differential signal induced by the gapped coaxial cable to a real magnetic field signal, and the output end of the integration circuit is connected to the input end of the high input impedance amplifier circuit;

[0013] The high input impedance amplifier circuit is used to collect and amplify the real magnetic field signal, and the output end of the high input impedance amplifier circuit is connected to the input end of the electro-optical conversion circuit;

[0014] The electro-optical conversion circuit is used to convert the real magnetic field signal into an optical signal and output the optical signal.

[0015] Furthermore, the integration circuit includes an input resistor R1, a current limiting resistor R2 and an integration capacitor C1;

[0016] One end of the current-limiting resistor R2 is connected to one end of the input resistor R1 as the input end of the integration circuit and is also connected to one end of the inner core; the other end of the current-limiting resistor R2 is connected to one side plate of the integration capacitor C1 as the output end of the integration circuit and is also connected to the input end of the high input impedance amplifier circuit;

[0017] The other end of the input resistor R1 is grounded, and the other side of the plate of the integrating capacitor C1 is grounded.

[0018] Furthermore, the resistance of the current limiting resistor R2 is much greater than the resistance of the input resistor R1.

[0019] Furthermore, the characteristic impedance, load resistance and resistance value of the gapped coaxial cable are consistent with those of the input resistor R1.

[0020] Furthermore, the annular gap width of the gapped coaxial cable is less than 1 mm.

[0021] Furthermore, the output end of the electro-optical conversion circuit is connected to an optical fiber.

[0022] Furthermore, the electro-optical conversion circuit adopts a DFB laser, which has a small size and low power consumption.

[0023] Furthermore, the high input impedance amplifier circuit includes an operational amplifier, a ground resistor R3, a first adjustment resistor R4 and a second adjustment resistor R5;

[0024] The non-inverting input terminal of the operational amplifier is connected to the output terminal of the integration circuit 3 and one end of the ground resistor R3; the inverting input terminal of the operational amplifier is connected to one end of the first adjustment resistor R4 and one end of the second adjustment resistor R5; the output terminal of the operational amplifier is connected to the input terminal of the electro-optical conversion circuit and the other end of the first adjustment resistor R4;

[0025] The other end of the ground resistor R3 is grounded, and the other end of the second adjustment resistor R5 is grounded.

[0026] Furthermore, since the input impedance of a FET-type operational amplifier is generally large, generally greater than MΩ, the operational amplifier described in the present invention is a FET-type operational amplifier;

[0027] The resistance of the ground resistor R3 is not less than 1MΩ;

[0028] The input impedance of the operational amplifier is not less than 10 MΩ.

[0029] The present invention also provides an electromagnetic pulse measurement method, which is special in that it includes the following steps:

[0030] Step 1: Place the magnetic field probe for electromagnetic pulse measurement in the magnetic field to be measured. The gapped coaxial cable collects the magnetic field differential signal of the electromagnetic pulse and transmits it to the integration circuit. The relationship between the magnetic field differential signal and the voltage difference generated between the gaps of the gapped coaxial cable is expressed by the following formula:

[0031]

[0032] Where V0 H is the voltage difference generated between the gaps of the coaxial cable with gaps, H is the magnetic field intensity, μ0 is the vacuum permeability, A eq is the equivalent area of the gapped coaxial cable loop, is the magnetic field differential signal;

[0033] Step 2: The integration circuit integrates the magnetic field differential signal to obtain a real magnetic field signal, and outputs the real magnetic field signal to the high input impedance amplifier circuit;

[0034] The real magnetic field signal V out (t) is calculated by the following formula:

[0035]

[0036] Where τ is the time constant of the integrating circuit;

[0037] V in (t) is the input magnetic field differential signal,

[0038] Step 3: The high input impedance amplifier circuit amplifies the real magnetic field signal and outputs the amplified real magnetic field signal to the electro-optical conversion circuit;

[0039] Step 4: The electro-optical conversion circuit converts the amplified real magnetic field signal into an optical signal and outputs it, completing the measurement of the electromagnetic pulse.

[0040] Compared with the prior art, the present invention has the following beneficial technical effects:

[0041] 1. The magnetic field probe for electromagnetic pulse measurement provided by the present invention utilizes a coaxial cable with a gap and a shielding shell to form an inductive antenna. Compared with a single loop antenna, it has a stronger ability to resist electric field interference. In addition, the inner core of one end of the coaxial cable with a gap is connected to a matching load resistor, which can avoid reflection of high-frequency signals caused by impedance mismatch.

[0042] 2. The magnetic field probe for electromagnetic pulse measurement provided by the present invention integrates an integration circuit, a high input impedance amplifier circuit, and an electro-optical conversion circuit within a shielded shell. Its output signal is the original signal of the magnetic field waveform, avoiding the numerical integration required for differential measurement to restore the magnetic field waveform to be measured;

[0043] 3. The magnetic field probe for electromagnetic pulse measurement provided by the present invention has high integration and convenient engineering application. It is particularly suitable for measuring the magnetic field waveform of fast-front strong electromagnetic pulses and also has application prospects in fields such as electromagnetic compatibility.

[0044] 4. The magnetic field probe for electromagnetic pulse measurement provided by the present invention transmits the measurement signal over long distances via optical fiber. Compared with coaxial cables, optical fiber has the advantages of low long-distance transmission loss, light weight, and strong resistance to electromagnetic interference. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 A schematic diagram of the structure of a magnetic field probe for electromagnetic pulse measurement provided by the present invention;

[0046] Figure 2 A schematic diagram of an integration circuit, a high input impedance amplifier circuit, and an electro-optical conversion circuit in an embodiment of a magnetic field probe for electromagnetic pulse measurement provided by the present invention;

[0047] Figure 3 A comparison diagram of the high-altitude electromagnetic pulse magnetic field signal waveform and the pulse source waveform measured in a TEM chamber using a magnetic field probe for electromagnetic pulse measurement provided by an embodiment of the present invention;

[0048] The following are the descriptions of the reference numerals:

[0049] 1-gap coaxial cable, 11-inner core, 12-shielding layer, 2-shielding shell, 3-integrating circuit, 4-high input impedance amplifier circuit, 5-electro-optical conversion circuit, 6-optical fiber, 7-load resistor. DETAILED DESCRIPTION

[0050] To make the objects, advantages and features of the present invention more clear, a magnetic field probe for electromagnetic pulse measurement proposed by the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0051] A magnetic field probe for electromagnetic pulse measurement, such as Figure 1As shown, it includes a coaxial cable with a gap 1, a shielding shell 2, and an integration circuit 3, a high input impedance amplifier circuit 4, an electro-optical conversion circuit 5 and a load resistor 7 arranged in the shielding shell 2. Its output signal is the original signal of the magnetic field waveform, which avoids the numerical integration required for differential measurement to restore the magnetic field waveform to be measured. The shielding shell 2 is provided with two connection ports for connecting the coaxial cable with a gap 1. The coaxial cable with a gap 1 is semicircular and includes an inner core 11 and a shielding layer 12 wrapped around the surface of the inner core 11. An annular gap is provided on the shielding layer 12 along the circumference. The smaller the value range of the annular gap, the better. In this embodiment, the annular gap is less than 1 mm. The two ends of the inner core 11 extend into the interior of the shielding shell 2 through two connection ports respectively, and are respectively connected to the input end of the integration circuit 3 and one end of the load resistor 7. The other end of the load resistor 7 is grounded. The gapped coaxial cable 1 is used to sense magnetic field differential signals. The inner core of one end of the cable is connected to a matching load resistor 7, which can avoid reflection of high-frequency signals due to impedance mismatch. Compared with a single loop antenna, the gapped coaxial cable 1 has a stronger ability to resist electric field interference.

[0052] Integrator circuit 3 is used to convert the magnetic field differential signal sensed by gapped coaxial cable 1 into a true magnetic field signal. The output of integrator circuit 3 is connected to the input of high-input impedance amplifier circuit 4. High-input impedance amplifier circuit 4 is used to collect and amplify the true magnetic field signal. The output of high-input impedance amplifier circuit 4 is connected to the input of electro-optical conversion circuit 5. Electro-optical conversion circuit 5 is used to convert the true magnetic field signal into an optical signal and output it. The output of electro-optical conversion circuit 5 is connected to optical fiber 6. Because optical fiber 6 has advantages such as low long-distance transmission loss, light weight, and strong resistance to electromagnetic interference, the measurement signal of the magnetic field probe for electromagnetic pulse measurement provided by the present invention is transmitted over long distances via optical fiber 6.

[0053] The gapped coaxial cable 1 uses SR086-50 coaxial cable with a characteristic impedance of 50Ω. The cable is made into a semicircle with a radius of 1.5cm and a gap of 1mm in the middle. Both ends extend into the interior of the shielding shell 2. One end of the inner core at both ends is connected to the integration circuit 3, and the other end is connected to the load resistor 7. The input resistance of the integration circuit 3 and the resistance of the load resistor 7 are both 50Ω.

[0054] When the electromagnetic pulse irradiates the magnetic field probe, the loop composed of the gapped coaxial cable and the shielding shell changes due to the magnetic flux, and a voltage difference V0 is generated between the gaps of the gapped coaxial cable. H for:

[0055]

[0056] Where H is the magnetic field intensity, μ0 is the vacuum permeability, and A eq is the equivalent area of the coaxial cable loop with gap. It can be seen from the formula that the magnetic field differential signal is related to V0H Directly proportional.

[0057] The electric field component in the electromagnetic pulse will generate a voltage difference between the gaps of the gapped coaxial cable 1, and the electric field component will be decomposed into an electric field E perpendicular to the gap of the gapped coaxial cable. ⊥ and the electric field E parallel to the gap of the coaxial cable with a gap ∥ . E ⊥ The voltage generated at both ends of the gap is a common mode voltage in the same direction, E ∥ The voltage generated at both ends of the gap is a reverse differential voltage, so the voltage difference between the gaps is only related to E ∥ Due to the existence of the shielding shell, according to the limitations of the electromagnetic field boundary conditions, E ∥ The standing wave distribution is on the shell interface, and E ∥ When the height of the gapped coaxial cable is less than the wavelength of the electromagnetic wave to be measured, E ∥ The electric field strength at the gap position is still very small, so the effect on the voltage difference between the gaps can be ignored, and the total voltage between the gaps of the coaxial cable with gaps is still approximately V0. H The electric field is formed due to the voltage difference between the gaps. The electric field acts on the inner core of the coaxial cable with gap 1 to form a point voltage source, the magnitude of which is approximately equal to V0. H The two ends of the inner core 11 are connected to the input resistor R1 and the load resistor 7 of the integration circuit 3 respectively. The input resistor R1 and the load resistor 7 have the same characteristic impedance as the gapped coaxial cable 1, thus forming a good match and no high-frequency reflection. Therefore, the voltage on each load is V0 H / 2.

[0058] like Figure 2 As shown, the integration circuit 3 includes an input resistor R1, a current limiting resistor R2 and an integration capacitor C1. One end of the current limiting resistor R2 is connected to one end of the input resistor R1, serving as the input end of the integration circuit, and is also connected to one end of the inner core 11. The other end of the current limiting resistor R2 is connected to one side plate of the integration capacitor C1, serving as the output end of the integration circuit 3, and is also connected to the input end of the high input impedance amplifier circuit 4. The other end of the input resistor R1 is grounded, and the other side plate of the integration capacitor C1 is grounded. The resistance of the current limiting resistor R2 is much greater than the resistance of the input resistor R1. The characteristic impedance of the gapped coaxial cable 1 and the load resistor 7 are consistent with the resistance of the input resistor R1.

[0059] The integration circuit 3 integrates the differential signal of the sensed magnetic field. The input resistor R1 (i.e., the antenna load) of the integration circuit 3 is 50Ω, the current limiting resistor R2 is 1kΩ, and the integration capacitor C1 is 1nF. The time constant of the integration circuit 3 is R2·C1=1μs. When the width of the pulse waveform to be measured is much smaller than 1μs, the voltage V on the capacitor C1 is out(t) is the input voltage V in (t) is the integral of time t, that is,

[0060]

[0061] The high-input-impedance amplifier circuit 4 includes a FET-type operational amplifier, a ground resistor R3, a first adjustment resistor R4, and a second adjustment resistor R5. The non-inverting input terminal of the FET-type operational amplifier is connected to the output terminal of the integration circuit 3 and one end of the ground resistor R3. The inverting input terminal of the FET-type operational amplifier is connected to one end of the first adjustment resistor R4 and one end of the second adjustment resistor R5. The output terminal of the FET-type operational amplifier is connected to the input terminal of the electro-optical conversion circuit 5 and the other end of the first adjustment resistor R4. The other end of the ground resistor R3 is grounded, and the other end of the second adjustment resistor R5 is grounded. The high-input-impedance amplifier circuit 4 also includes two capacitors, one of which has one plate connected to the positive terminal of the power input of the FET-type operational amplifier and the other plate grounded; the other capacitor has one plate connected to the negative terminal of the power input of the FET-type operational amplifier and the other plate grounded.

[0062] The FET operational amplifier uses a parallel resistor to ground, R3, to prevent malfunction due to a lack of a DC path at the input. The resistance of R3 to ground is no less than 1MΩ. High-input-impedance amplifier circuit 4 is used to collect the voltage across capacitor C1 in the integration circuit. This circuit is centered around a FET operational amplifier, with its positive input acting as the signal input. The input impedance can be as high as or above GΩ. With a parallel resistor to ground, R3 is set to 1MΩ, and the input impedance of the circuit is approximately equal to the resistance of R4. Assuming R4 = R5, which is 150Ω, the FET operational amplifier amplifies the input signal by a factor of 2.

[0063] The electro-optical conversion circuit 5 includes a DFB laser, resistors R6 and R7, and a capacitor C2. One end of resistor R6 serves as the input of the electro-optical conversion circuit 5 and is connected to the output of the FET operational amplifier. The other end of resistor R6 is connected to one plate of capacitor C2. The other plate of capacitor C2 is connected to one end of resistor R7 and the anode of the DFB laser. The other end of resistor R7 is connected to a power supply. The cathode of the DFB laser is grounded.

[0064] The output end of the electro-optical conversion circuit 5 is connected to an optical fiber, and the signal output by the high input impedance amplifier circuit is transmitted through the optical fiber using a DFB laser to prevent the transmission link from being interfered by strong electromagnetic pulses.

[0065] The magnetic field probe for electromagnetic pulse measurement provided by the present invention has good resistance to electric field interference. The internal integration circuit 3 and the matching high input impedance amplifier circuit 4 can convert the differential signal induced by the antenna into a real magnetic field signal and transmit the signal through the optical fiber, which can avoid the transmission link from being interfered with by the secondary electromagnetic pulse. It also has the advantages of easy use, high integration, and convenient engineering application.

[0066] like Figure 3 As shown, there is a comparison diagram of the high-altitude electromagnetic pulse magnetic field signal waveform and the pulse source waveform measured by the magnetic field probe for electromagnetic pulse measurement provided by the present invention under the TEM chamber. It can be seen that the waveform measured by the magnetic field probe for electromagnetic pulse measurement provided by the present invention is in good compliance with the pulse source waveform. The magnetic field probe for electromagnetic pulse measurement provided by the present invention has a strong ability to resist electric field interference and is suitable for measuring fast-front pulse magnetic field signals.

[0067] This embodiment also provides an electromagnetic pulse measurement method, comprising the following steps:

[0068] Step 1: Place the magnetic field probe for electromagnetic pulse measurement in the magnetic field to be measured. The gapped coaxial cable 1 collects the magnetic field differential signal of the electromagnetic pulse and transmits it to the integration circuit 3. The relationship between the magnetic field differential signal and the voltage difference generated between the gaps of the gapped coaxial cable 1 is expressed by the following formula:

[0069]

[0070] Where V0 H is the voltage difference generated between the gaps of the gapped coaxial cable 1, H is the magnetic field intensity, μ0 is the vacuum permeability, A eq is the equivalent area of the gapped coaxial cable loop, is the magnetic field differential signal, which serves as the input signal V of the integration circuit 3 in (t), let

[0071] Step 2: The integration circuit 3 integrates the magnetic field differential signal to obtain a real magnetic field signal, and outputs the real magnetic field signal to the high input impedance amplifier circuit 4;

[0072] The real magnetic field signal V out (t) is calculated by the following formula:

[0073]

[0074] Wherein, τ is the time constant of the integration circuit 3;

[0075] V in (t) is the input magnetic field differential signal,

[0076] Step 3: The high input impedance amplifier circuit 4 amplifies the real magnetic field signal and outputs the amplified real magnetic field signal to the electro-optical conversion circuit 5;

[0077] Step 4: The electro-optical conversion circuit 5 converts the amplified real magnetic field signal into an optical signal and outputs it, completing the measurement of the electromagnetic pulse.

Claims

1. A magnetic field probe for electromagnetic pulse measurement, characterized in that: The invention comprises a coaxial cable with a gap (1), a shielding shell (2), and an integrating circuit (3), a high input impedance amplifier circuit (4), an electro-optical conversion circuit (5), and a load resistor (7) arranged in the shielding shell (2); The shielding shell (2) is provided with two connection ports for connecting the gapped coaxial cable (1); The gapped coaxial cable (1) is semicircular and comprises an inner core (11) and a shielding layer (12) wrapped around the surface of the inner core (11); an annular gap of less than 1 mm is provided on the shielding layer (12) along the circumferential direction; two ends of the inner core (11) extend into the interior of the shielding shell (2) through two connection ports, and are respectively connected to the input end of the integration circuit (3) and one end of the load resistor (7); the other end of the load resistor (7) is grounded; The gapped coaxial cable (1) is used for inducing a magnetic field differential signal; The integration circuit (3) is used to restore the magnetic field differential signal induced by the gapped coaxial cable (1) into a real magnetic field signal, and the output end of the integration circuit (3) is connected to the input end of the high input impedance amplifier circuit (4); The high input impedance amplifier circuit (4) is used to collect and amplify the real magnetic field signal, and the output end of the high input impedance amplifier circuit (4) is connected to the input end of the electro-optical conversion circuit (5); The electro-optical conversion circuit (5) is used to convert the real magnetic field signal into an optical signal and output the optical signal.

2. The magnetic field probe for electromagnetic pulse measurement according to claim 1, characterized in that: The integration circuit (3) comprises an input resistor R1, a current limiting resistor R2 and an integration capacitor C1; One end of the current-limiting resistor R2 is connected to one end of the input resistor R1, serving as the input end of the integration circuit (3), and is also connected to one end of the inner core (11); the other end of the current-limiting resistor R2 is connected to one side plate of the integration capacitor C1, serving as the output end of the integration circuit (3), and is also connected to the input end of the high-input-impedance amplifier circuit (4); The other end of the input resistor R1 is grounded, and the other side of the plate of the integrating capacitor C1 is grounded.

3. The magnetic field probe for electromagnetic pulse measurement according to claim 2, characterized in that: The resistance of the current limiting resistor R2 is much greater than the resistance of the input resistor R1.

4. The magnetic field probe for electromagnetic pulse measurement according to claim 3, characterized in that: The characteristic impedance of the gapped coaxial cable (1), the load resistor (7), and the input resistor R1 have the same resistance value.

5. The magnetic field probe for electromagnetic pulse measurement according to any one of claims 1 to 4, characterized in that: The output end of the electro-optical conversion circuit (5) is connected to an optical fiber (6).

6. The magnetic field probe for electromagnetic pulse measurement according to claim 5, characterized in that: The electro-optical conversion circuit (5) adopts a DFB laser.

7. The magnetic field probe for electromagnetic pulse measurement according to claim 6, characterized in that: The high input impedance amplifier circuit (4) comprises an operational amplifier, a ground resistor R3, a first adjustment resistor R4 and a second adjustment resistor R5; The non-inverting input terminal of the operational amplifier is connected to the output terminal of the integration circuit (3) and one end of the ground resistor R3; the inverting input terminal of the operational amplifier is connected to one end of the first adjustment resistor R4 and one end of the second adjustment resistor R5; the output terminal of the operational amplifier is connected to the input terminal of the electro-optical conversion circuit (5) and the other end of the first adjustment resistor R4; The other end of the ground resistor R3 is grounded, and the other end of the second adjustment resistor R5 is grounded.

8. The magnetic field probe for electromagnetic pulse measurement according to claim 7, characterized in that: The operational amplifier is a FET type operational amplifier; The resistance of the ground resistor R3 is not less than 1MΩ; The input impedance of the operational amplifier is not less than 10 MΩ.

9. An electromagnetic pulse measurement method, characterized in that: The following steps are involved: Step 1: Place the magnetic field probe for electromagnetic pulse measurement according to any one of claims 1 to 8 in the magnetic field to be measured, collect the magnetic field differential signal of the electromagnetic pulse through the gapped coaxial cable (1), and transmit it to the integration circuit (3). The relationship between the magnetic field differential signal and the voltage difference generated between the gaps of the gapped coaxial cable (1) is expressed by the following formula: Where, is the voltage difference generated between the gaps of the gapped coaxial cable (1), H is the magnetic field intensity, μ0 is the vacuum permeability, A eq is the equivalent area of the gapped coaxial cable loop, is the magnetic field differential signal; Step 2: The integration circuit (3) integrates the magnetic field differential signal to obtain a real magnetic field signal, and outputs the real magnetic field signal to the high input impedance amplifier circuit (4); The real magnetic field signal V out (t) is calculated by the following formula: Where, τ is the time constant of the integration circuit (3); V in (t) is the input magnetic field differential signal, Step 3: The high input impedance amplifier circuit (4) amplifies the real magnetic field signal and outputs the amplified real magnetic field signal to the electro-optical conversion circuit (5); Step 4: The electro-optical conversion circuit (5) converts the amplified real magnetic field signal into an optical signal and outputs it, completing the measurement of the electromagnetic pulse.

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