Pulsed electric field measurement system and temperature compensation method thereof

Abstract

The present invention provides a pulsed electric field measurement system and a temperature compensation method thereof, aiming to address the technical problem that the electro-optical conversion efficiency of a laser varies with temperature, affecting the stability of the pulsed electric field measurement system. The pulsed electric field measurement system includes a pulsed electric field measurement circuit, which includes a monopole antenna, a high-impedance input operational amplifier, a semiconductor laser, and a power supply module. The monopole antenna is sequentially connected to the high-impedance input operational amplifier and the semiconductor laser; the high-impedance input operational amplifier includes a grounding resistor and a feedback resistor, both of which are negative temperature coefficient thermistors; the monopole antenna couples to a spatial electric field; the high-impedance input operational amplifier is used to convert the high-impedance signal into a low-impedance signal and input it into the semiconductor laser; and the power supply module provides power to the entire pulsed electric field measurement circuit. The present invention also provides a temperature compensation method for the pulsed electric field measurement system.

Description

Technical Field

[0001] The present invention relates to a pulse electric field measurement system, in particular to a pulse electric field measurement system and a temperature compensation method thereof. Background Art

[0002] Electromagnetic security, as a crucial component of national security strategy, is a national priority. Strong electromagnetic environments, such as high-altitude electromagnetic pulse (HEMP), high-power microwave (HPM), ultra-wideband electromagnetic pulse (UWB), and lightning electromagnetic pulse (LEMP), are key areas of concern for electromagnetic security. Electromagnetic pulse (EMP) environments have broad spectrums, high field strengths, and extensive coverage, posing a threat to a wide range of electronic devices. Pulsed electric field measurement, as a key means of acquiring data, is crucial in the EMP field. Transient pulse electric field measurement has a history of over half a century, resulting in numerous measurement systems. However, due to persistent measurement challenges and increasing measurement requirements, research in pulsed electric field measurement technology has remained a key focus in the EMP field.

[0003] Transient electromagnetic pulse signals are typical non-stationary signals. In the time domain, they appear as a single or a series of pulse signals with fast rising edges, short durations, and drastic amplitude changes. In the frequency domain, they have an extremely wide spectrum range. The time domain waveform is prone to varying degrees of distortion during propagation, radiation, scattering, and penetration.

[0004] Active integrating electric field sensors based on electro-optical integration have developed into mainstream transient electric field measurement systems. At present, the main research directions in this field are concentrated in the following aspects:

[0005] a. Expand the test system test bandwidth;

[0006] b. Reduce the disturbance effect of the test system on the measured field;

[0007] c. Improve the reliability of the test system in complex test environments.

[0008] The complex test environment includes electromagnetic pulse radiation, temperature, humidity and other conditions. The temperature sensitivity problem of the pulse electric field measurement system mainly comes from the semiconductor laser in the photoelectric conversion module. When the ambient temperature rises, the laser luminous efficiency decreases, the output light power decreases, and the measurement system conversion coefficient increases; when the ambient temperature decreases, the laser luminous efficiency increases, the output light power increases, and the measurement system conversion coefficient decreases.

[0009] In previous studies, by adding an APC circuit to the electro-optical conversion module, the DC optical power of the laser does not change with temperature, ensuring the stability of the pulse electric field measurement system during actual use. Experiments have shown that as long as the measurement signal frequency is greater than 200Hz, the APC circuit will not affect the normal transmission of the measurement system. Figure 3 As shown in the figure, the currently used pigtailed DFB semiconductor laser module (DFB-Pigtail Laser Module) integrates the PD and LD together and connects to the external control circuit through different pins. However, the butterfly-packaged semiconductor laser with a built-in cooler can maintain the temperature of the laser light-emitting part constant within a certain temperature range, thereby maintaining the laser's electro-optical conversion efficiency and optical power stable. However, this type of laser is expensive, and in actual use, the electro-optical integrated pulse electric field measurement system is powered by a battery. This type of laser has high power and high power consumption, which increases the frequency of battery replacement in the measurement system and the maintenance cost of the measurement system. In addition, the accelerated battery discharge speed causes the battery output voltage to decay faster, increasing the system uncertainty.

[0010] Therefore, the electro-optical conversion efficiency of the laser changes with temperature, affecting the stability of the pulsed electric field measurement system. Summary of the Invention

[0011] The purpose of the present invention is to solve the technical problem that the electro-optical conversion efficiency of the existing laser varies with temperature, affecting the stability of the pulse electric field measurement system, and to provide a pulse electric field measurement system and a temperature compensation method thereof.

[0012] In order to solve the above technical problems, the present invention provides the following technical solutions.

[0013] A pulse electric field measurement system, including a pulse electric field measurement circuit, is special in that:

[0014] The pulse electric field measurement circuit includes a monopole antenna, a high-impedance input operational amplifier circuit, a semiconductor laser, and a power supply module; the monopole antenna is sequentially connected to the high-impedance input operational amplifier circuit and the semiconductor laser;

[0015] The high-resistance input operational amplifier circuit includes an operational amplifier, a grounding resistor, and a feedback resistor. The non-inverting input terminal of the operational amplifier is connected to the monopole antenna, the inverting input terminal is grounded via the grounding resistor, and the feedback resistor is connected between the inverting input terminal and the output terminal of the operational amplifier; the output terminal of the operational amplifier is connected to a semiconductor laser; the grounding resistor and the feedback resistor are both negative temperature coefficient thermistors, and the thermal sensitivity index of the grounding resistor is higher than that of the feedback resistor;

[0016] The monopole antenna couples the spatial electric field and inputs the electric signal into the high-impedance input operational amplifier circuit;

[0017] The high-resistance input operational amplifier circuit is used to amplify the high-resistance electrical signal and then output a low-resistance electrical signal to input into the semiconductor laser;

[0018] The semiconductor laser is used to convert the low-resistance electrical signal into an optical signal and transmit it to the back-end optical receiver;

[0019] The power supply module provides power for the monopole antenna, the high-resistance input operational amplifier circuit, and the semiconductor laser.

[0020] Furthermore, the semiconductor laser adopts a pigtailed DFB semiconductor;

[0021] The pigtailed DFB semiconductor integrates the PD and LD together and connects them to the external control circuit through different pins.

[0022] Furthermore, the semiconductor laser transmits the optical signal to the optical receiver via an optical fiber.

[0023] The temperature compensation method based on the above-mentioned pulse electric field measurement system is special in that it includes the following steps:

[0024] 1) The pulse electric field measurement circuit uses a monopole antenna to couple the spatial electric field, and amplifies the electrical signal through a high-impedance input operational amplifier circuit and then inputs it into a semiconductor laser. The semiconductor laser converts the electrical signal into an optical signal and transmits it to the back-end optical receiver;

[0025] 2) When the ambient temperature rises, the resistance of the grounding resistor and the feedback resistor decreases, causing the amplification factor of the high-resistance input operational amplifier to increase with the temperature. At the same time, the electro-optical conversion coefficient of the semiconductor laser decreases with the temperature, thereby suppressing the deviation of the conversion coefficient of the pulsed electric field measurement circuit caused by temperature changes and realizing temperature compensation of the pulsed electric field measurement system.

[0026] When the ambient temperature drops, the resistance of the grounding resistor and the feedback resistor increases, causing the amplification factor of the high-resistance input operational amplifier circuit to decrease as the temperature drops. At the same time, the electro-optical conversion coefficient of the semiconductor laser increases as the temperature drops, thereby suppressing the offset of the conversion coefficient of the pulse electric field measurement circuit caused by temperature changes and realizing temperature compensation of the pulse electric field measurement system.

[0027] Furthermore, in step 1), the conversion coefficient K of the pulse electric field measurement circuit is:

[0028] K = Tr × G;

[0029] in:

[0030] Tr is the electro-optical conversion coefficient of the semiconductor laser;

[0031] G is the gain of the high-resistance input operational amplifier circuit, G=1+R1 / R2, R1 is the feedback resistance value, and R2 is the grounding resistance value.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] 1. A pulsed electric field measurement system of the present invention, by setting the grounding resistor and feedback resistor of a high-resistance input operational amplifier as negative temperature coefficient thermistors, compensates for the temperature offset of the electro-optical conversion coefficient of a semiconductor laser when the ambient temperature changes, thereby improving the temperature stability of the conversion coefficient of the pulsed electric field measurement system.

[0034] 2. The temperature compensation method of the pulse electric field measurement system of the present invention is simple and easy to implement. It is carried out on the original pulse electric field measurement circuit with low modification cost and significant effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 A schematic diagram of a measurement circuit of an embodiment of a pulse electric field measurement system of the present invention;

[0036] Figure 2 Schematic diagram of converting a follower circuit into an amplifier circuit in an embodiment of a pulse electric field measurement system of the present invention (wherein a is a follower circuit and b is an amplifier circuit);

[0037] Figure 3 A schematic diagram of the pin connections of a pigtailed DFB semiconductor laser according to an embodiment of a pulsed electric field measurement system of the present invention;

[0038] The following are the descriptions of the reference numerals:

[0039] 1-Monopole antenna, 2-High impedance input operational amplifier circuit, 3-Semiconductor laser. DETAILED DESCRIPTION

[0040] The present invention will be further described below with reference to the accompanying drawings and examples.

[0041] The present invention provides a pulsed electric field measurement system that can offset the impact of ambient temperature changes on the stability of the pulsed electric field measurement system. A monopole antenna 1 senses the electric field in space, generating an induced current. This current is then connected to an integrated operational amplifier (OPA) that converts the high-resistance electrical signal at the front end into a low-resistance signal, which is then input into a semiconductor laser 3. The output optical power of the semiconductor laser 3 is affected by the input current, and the electrical signal is converted into an optical signal. This optical signal is then transmitted via optical fiber to a back-end optical receiver, which converts the optical signal into an electrical signal and filters out the DC component in the signal, ultimately obtaining the time-domain waveform of the pulsed electric field.

[0042] like Figure 1As shown, a pulse electric field measurement system of the present invention includes a pulse electric field measurement circuit, which includes a monopole antenna 1, a high-impedance input operational amplifier circuit 2, a semiconductor laser 3 and a power supply module; the monopole antenna 1 is connected to the high-impedance input operational amplifier circuit 2 and the semiconductor laser 3 in sequence; the high-impedance input operational amplifier circuit 2 includes an operational amplifier, a grounding resistor and a feedback resistor, the in-phase input terminal of the operational amplifier is connected to the monopole antenna 1, the inverting input terminal is grounded through the grounding resistor, and the feedback resistor is connected between the inverting input terminal and the output terminal of the operational amplifier; the output terminal of the operational amplifier is connected to the semiconductor laser The optical device 3 and the semiconductor laser 3 are fiber-pigtailed DFB semiconductor lasers; the grounding resistor is a negative temperature coefficient thermistor, and the value of the grounding resistor is less than the value of the feedback resistor; the monopole antenna 1 couples the spatial electric field and inputs the electrical signal into the high-resistance input operational amplifier circuit 2; the high-resistance input operational amplifier circuit 2 is used to amplify the high-resistance electrical signal and output a low-resistance electrical signal and input it into the semiconductor laser 3; the semiconductor laser 3 converts the low-resistance electrical signal into an optical signal and transmits it to the back-end optical receiver through an optical fiber; the power module provides power for the monopole antenna 1, the high-resistance input operational amplifier circuit 2, and the semiconductor laser 3.

[0043] The principle of the pulse electric field measurement circuit is as follows: the feedback resistor and grounding resistor of the high-resistance input operational amplifier 2 in the circuit are replaced with a negative temperature thermistor. When the ambient temperature changes, the amplification factor of the integrated operational amplifier and the change trend of the electro-optical conversion efficiency of the semiconductor laser 3 are opposite and offset each other, ultimately achieving the goal of keeping the conversion coefficient of the test circuit stable with respect to the ambient temperature. The conversion coefficient of the pulse electric field measurement circuit is K = Tr × G, where Tr is the electro-optical conversion coefficient of the semiconductor laser 3 and G is the amplification factor of the high-resistance input operational amplifier 2. When the ambient temperature changes, the electro-optical conversion coefficient of the semiconductor laser 3 changes, causing the system conversion coefficient to change, affecting the measurement results. Figure 2 As shown, by changing the follower circuit of the integrated operational amplifier into an amplifier circuit, the amplification factor of the integrated operational amplifier is G=1+R1 / R2, where R1 is the feedback resistance value and R2 is the grounding resistance value.

[0044] The temperature compensation method based on the above-mentioned pulse electric field measurement system has the following characteristics:

[0045] 1) The pulse electric field measurement circuit uses a monopole antenna 1 to couple the spatial electric field, and then amplifies the electric signal through a high-impedance input operational amplifier circuit 2 and inputs it into a semiconductor laser 3. The semiconductor laser 3 converts the electric signal into an optical signal and transmits it to the back-end optical receiver;

[0046] 2) When the ambient temperature rises, the resistance of the grounding resistor and the feedback resistor decreases, causing the amplification factor of the high-resistance input operational amplifier 2 to increase with the temperature. At the same time, since the electro-optical conversion coefficient of the semiconductor laser 3 decreases with the temperature increase, the two offset each other, thereby suppressing the offset of the conversion coefficient of the pulsed electric field measurement circuit caused by temperature changes, and realizing temperature compensation of the pulsed electric field measurement system.

[0047] When the ambient temperature drops, the resistance values of the grounding resistor and the feedback resistor increase, causing the amplification factor of the high-resistance input operational amplifier circuit 2 to decrease as the temperature drops; at the same time, the electro-optical conversion coefficient of the semiconductor laser 3 increases as the temperature drops, and the two offset each other, thereby suppressing the offset of the conversion coefficient of the pulse electric field measurement circuit caused by temperature changes and realizing temperature compensation of the pulse electric field measurement system.

[0048] In the above step 1), the conversion coefficient K of the pulse electric field measurement circuit is:

[0049] K = Tr × G;

[0050] in:

[0051] Tr is the electro-optical conversion coefficient of semiconductor laser 3;

[0052] G is the gain of the high-impedance input operational amplifier 2, G=1+R1 / R2, R1 is the feedback resistor value, and R2 is the grounding resistor value.

[0053] The negative temperature coefficient thermistor used in the present invention is an NTC thermistor.

[0054] The usual calculation formula: R T =R0·exp[B·(1 / T-1 / T0)]

[0055] Among them, R T is the resistance of the NTC thermistor at temperature T, R0 is the resistance of the NTC thermistor at temperature T0, and B is the thermal sensitivity index;

[0056] As mentioned above, the feedback resistance and grounding resistance can be expressed as:

[0057] Feedback resistor: in is the resistance of the feedback resistor R1 at temperature T0;

[0058] Ground resistance: in is the resistance of the grounding resistor R2 at temperature T0;

[0059] Substituting the above expressions for feedback resistance and ground resistance into G=1+R1 / R2, we have:

[0060] G=1+A·exp[ΔB·(1 / T-1 / T o )];

[0061] in,

[0062] To achieve temperature compensation of the measurement system conversion coefficient, it is generally required that:

[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. For ordinary professional and technical personnel in this field, the specific technical solutions recorded in the above embodiments can be modified, or some of the technical features therein can be replaced by equivalents. These modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions protected by the present invention.

Claims

1. A pulse electric field measurement system, comprising a pulse electric field measurement circuit, characterized in that: The pulse electric field measurement circuit comprises a monopole antenna (1), a high-resistance input operational amplifier circuit (2), a semiconductor laser (3), and a power supply module; the monopole antenna (1) is sequentially connected to the high-resistance input operational amplifier circuit (2) and the semiconductor laser (3); The high-resistance input operational amplifier circuit (2) comprises an operational amplifier, a grounding resistor, and a feedback resistor; the in-phase input terminal of the operational amplifier is connected to the monopole antenna (1), the inverting input terminal is grounded via the grounding resistor, and the feedback resistor is connected between the inverting input terminal and the output terminal of the operational amplifier; the output terminal of the operational amplifier is connected to a semiconductor laser (3); the grounding resistor and the feedback resistor are both negative temperature coefficient thermistors, and the thermal sensitivity index of the grounding resistor is higher than that of the feedback resistor; The monopole antenna (1) couples the spatial electric field and inputs the electric signal into the high-resistance input operational amplifier circuit (2); The high-resistance input operational amplifier circuit (2) is used to amplify the high-resistance electrical signal and then output a low-resistance electrical signal to input into the semiconductor laser (3); The semiconductor laser (3) is used to convert the low-resistance electrical signal into an optical signal and transmit it to a back-end optical receiver; The power supply module provides power for the monopole antenna (1), the high-resistance input operational amplifier circuit (2), and the semiconductor laser (3).

2. The pulse electric field measurement system according to claim 1, characterized in that: The semiconductor laser (3) is a pigtail-type DFB semiconductor laser.

3. The pulse electric field measurement system according to claim 2, wherein: The semiconductor laser (3) transmits the optical signal to the optical receiver via the optical fiber.

4. A temperature compensation method for a pulse electric field measurement system according to any one of claims 1 to 3, characterized in that: The following steps are involved: 1) The pulse electric field measurement circuit utilizes a monopole antenna (1) to couple the spatial electric field, and amplifies the electric signal through a high-impedance input operational amplifier circuit (2) and then inputs it into a semiconductor laser (3). The semiconductor laser (3) converts the electric signal into an optical signal and transmits it to a back-end optical receiver. 2) When the ambient temperature rises, the resistance values of the grounding resistor and the feedback resistor decrease, so that the amplification factor of the high-resistance input operational amplifier circuit (2) increases with the temperature increase; at the same time, the electro-optical conversion coefficient of the semiconductor laser (3) decreases with the temperature increase, thereby suppressing the deviation of the conversion coefficient of the pulse electric field measurement circuit caused by temperature changes, and realizing temperature compensation of the pulse electric field measurement system; When the ambient temperature decreases, the resistance of the grounding resistor and the feedback resistor increases, so that the amplification factor of the high-resistance input operational amplifier circuit (2) decreases as the temperature decreases; At the same time, the electro-optical conversion coefficient of the semiconductor laser (3) increases as the temperature decreases, thereby suppressing the deviation of the conversion coefficient of the pulse electric field measurement circuit caused by temperature changes and realizing temperature compensation of the pulse electric field measurement system.

5. The temperature compensation method for a pulsed electric field measurement system according to claim 4, wherein: In step 1), the conversion coefficient K of the pulse electric field measurement circuit is: K = Tr × G; in: Tr is the electro-optical conversion coefficient of the semiconductor laser (3); G is the amplification factor of the high-resistance input operational amplifier circuit (2), G=1+R1 / R2, R1 is the feedback resistance value, and R2 is the grounding resistance value.

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