KR20210131178A - Simulated hemp measurement system using fiber-optic data link, computer-readable storage medium and computer program - Google Patents

Abstract

The present invention relates to a HEMP measurement method using an optical data link system, which includes: a step of collecting a time-domain HEMP electric field strength signal through an optical data link; a step of converting the time-domain HEMP electric field strength signal into a frequency-domain HEMP electric field strength signal by Fourier transform; a step of compensating the frequency-domain HEMP electric field strength signal using an integrator transfer function; a step of converting the compensated frequency-domain HEMP electric field strength signal into a time-domain HEMP electric field strength signal by inverse Fourier transform; and a step of compensating the signal strength in accordance with differential detector constant, dielectric constant, balun attenuation value, and integrator time constant.

Description

HEMP measurement method and apparatus using optical data link system, computer readable recording medium and computer program

The embodiment relates to a HEMP measuring apparatus and method using an optical data link system.

In general, in modern society, electronic devices are miniaturized and integrated, and are deeply involved in our lives like smartphones. These various electrical, electronic and communication devices can be paralyzed in an instant by the powerful electromagnetic pulse (EMP, Electro Magnetic Pulse) generated when a nuclear explosion occurs.

In particular, HEMP (High-altitude Electro Magnetic Pulse) generated during a high-altitude nuclear explosion 30 km above the ground affects electronic devices and communication facilities in all areas located in the line of sight from the point of explosion to the ground. Accordingly, important national facilities and various weapon systems must ensure survivability in the HEMP environment.

To ensure this, it is necessary to test the immunity in the simulated HEMP environment for the relevant facilities and equipment, and it should be accompanied by the measurement of the electric/magnetic field strength for the authorized HEMP. In order to generate simulated HEMP, HEMP simulator is required, which is composed of high voltage pulse generator, antenna structure, terminating resistor, and ground plane. Generally, a Bounded-wave simulator that generates vertically polarized electromagnetic waves is used. The shape of the simulated HEMP waveform follows the public HEMP waveform presented in the specification established by the International Electrotechnical Commission, and the waveform has the broadband characteristics shown in FIGS. 1 and 2 .

As shown in FIG. 3 , the electric/magnetic field strength measurement of the simulated HEMP is performed using a differential detector (D/B-dot), BALanced to Unbalanced (BALUN), an integrator, a coaxial cable, and an oscilloscope. However, when the measured signal is transmitted using a coaxial cable, as the length of the HEMP exposure of the corresponding cable increases, distortion of the original signal may occur due to the coupled signal and the loss in the high frequency band increases. do.

In order to overcome this, it is necessary to transmit a signal using an optical cable that is not affected by an electrical signal. In order to transmit a signal using an optical cable, it is essential to use a photoelectric conversion transceiver that converts an electrical signal and an optical signal.

에 해당하고, 안정적인 동작을 위해서는 입출력 신호가 수백 mV정도의 낮은 수준을 유지해야 한다. However, difficulties arise in the use of the integrator when using the photoelectric conversion transceiver. First of all, the characteristic of the photoelectric conversion transceiver is that the input/output impedance is 50

For stable operation, the input/output signal must be maintained at a low level of several hundred mV.

In order to convert the signal measured through the differential detector into an optical signal through the photoelectric conversion transmitter, the conversion may be performed by connecting the photoelectric conversion transmitter to the front or rear end of the integrator. First, let's assume that it is connected to the front end of the integrator. In the case of the integrator used to measure the HEMP signal, the time constant of the integrator must be large enough to sufficiently cover the bandwidth of the HEMP signal, and accordingly, the degree of attenuation of the signal strength is quite large.

However, since the output of the photoelectric conversion transceiver itself has a low level and the degree of attenuation by the integrator is large, the measured signal is buried in the noise layer of the oscilloscope, making measurement impossible. If the photoelectric conversion transmitter is connected to the rear end of the integrator, the performance of the integrator is considerably deteriorated due to the low impedance (50Ω) of the photoelectric conversion transmitter.

So, even when using a traditional coaxial cable and integrator, the measurement is performed by setting the input impedance of the oscilloscope connected to the output of the integrator to 1MΩ. In conclusion, when using the photoelectric conversion transceiver, there is a problem in that the reliability of measurement using the existing hardware integrator is considerably lowered.

In order to solve the above problems, the embodiment relates to a HEMP measurement method and apparatus using an optical data link system that replaces a time domain measurement system using a conventional coaxial cable and a hardware integrator.

The HEMP measurement method using the optical data link system of the embodiment includes collecting a HEMP electric field strength signal in a time domain through an optical data link, and converting the HEMP electric field strength signal in the time domain to a frequency domain using a Fourier transform technique (FFT). converting the HEMP electric field strength signal of ) to convert the HEMP electric field strength signal in the frequency domain into a HEMP electric field strength signal in the time domain using can

The HEMP measuring apparatus using the optical data link system of the embodiment includes a collecting unit that collects a HEMP electric field strength signal in a time domain through an optical data link, and a frequency using a Fourier transform technique (FFT) for the HEMP electric field strength signal in the time domain. A first converter for converting the HEMP electric field strength signal of a domain; a second transform unit that converts the HEMP electric field strength signal in the frequency domain into a HEMP electric field strength signal in the time domain using an inverse Fourier transform technique (IFFT), and a differential detector constant, permittivity, balun attenuation value, and integrator time constant. It may include a second compensator for compensating for the signal strength.

An embodiment is a computer readable recording medium storing a computer program, the computer program comprising the steps of: collecting a HEMP electric field strength signal in a time domain through an optical data link; and Fourier transforming the HEMP electric field strength signal in the time domain converting the HEMP electric field strength signal in the frequency domain using a technique (FFT); compensating the HEMP electric field strength signal in the frequency domain using an integrator transfer function; The step of converting the intensity signal into an HEMP electric field intensity signal in the time domain using an inverse Fourier transform technique (IFFT), and a differential detector constant, permittivity, balun attenuation value, and integrator time constant It may include instructions for causing the processor to perform an operation for performing the step of compensating for signal strength.

An embodiment is a computer program stored in a computer-readable recording medium, the computer program comprising the steps of: collecting a HEMP electric field strength signal in a time domain through an optical data link; and Fourier transforming the HEMP electric field strength signal in the time domain converting the HEMP electric field strength signal in the frequency domain using a technique (FFT); compensating the HEMP electric field strength signal in the frequency domain using an integrator transfer function; The step of converting the intensity signal into an HEMP electric field intensity signal in the time domain using an inverse Fourier transform technique (IFFT), and a differential detector constant, permittivity, balun attenuation value, and integrator time constant It may include instructions for causing the processor to perform an operation for performing the step of compensating for signal strength.

As the embodiment provides a system and a technique for measuring a simulated HEMP using an optical data link system, there is an effect that a measurement can be performed without distortion due to the HEMP signal combination of a cable.

1 is a graph showing a conventional HEMP waveform.
2 is a graph illustrating a conventional HEMP waveform frequency response characteristic.
3 is a diagram illustrating a conventional HEMP measurement system.
4 is a diagram illustrating a HEMP measurement system according to an embodiment.
5 is a diagram illustrating an HEMP measuring apparatus according to an embodiment.
6 is a flowchart illustrating a HEMP measurement method using the HEMP measurement apparatus according to an embodiment.
7 is a graph comparing frequency response characteristics according to an integrator time constant.
8 is a graph illustrating an integral waveform distorted by oscilloscope noise.

Hereinafter, the embodiment will be described in detail with reference to the drawings.

4 is a diagram illustrating a HEMP measurement system according to an embodiment, and FIG. 5 is a diagram illustrating a HEMP measurement apparatus according to an embodiment.

Referring to FIG. 4 , the HEMP measurement system according to the embodiment includes a differential detector (D/B-dot 100), a balun (BALanced to Unbalanced, BALUN, 200), a photoelectric conversion transmitter 300, and a photoelectric conversion receiver 400 ), an oscilloscope 500 , and a HEMP measuring device 600 .

The differential detector 100 may measure the electric field strength of the HEMP. The balun 200 may convert the shape and intensity of a signal output from the differential detector 100 . The photoelectric conversion transmitter 300 and the photoelectric conversion receiver 400 serve to convert an electrical signal into an optical signal or convert an optical signal into an electrical signal. The oscilloscope 500 may display an output voltage converted into an electrical signal. Here, the differential detector 100 , the balun 200 , the photoelectric conversion transmitter 300 , the photoelectric conversion receiver 400 , and the oscilloscope 500 may be components of the optical data link.

The HEMP measuring apparatus 600 according to the embodiment may measure the HEMP in which the signal strength is compensated by using a value output from the optical data link.

Referring to FIG. 5 , the HEMP measuring apparatus 600 according to the embodiment includes a collecting unit 610 , a first converting unit 620 , a first compensating unit 630 , and a second converting unit 640 , and , a second compensation unit 650 may be included.

The collection unit 610 may collect the HEMP electric field strength signal in the time domain through the optical data link. The first transform unit 620 may convert the HEMP electric field strength signal in the time domain into a HEMP electric field strength signal in the frequency domain by using a Fourier transform technique (FFT). The first compensator 630 may compensate the HEMP electric field strength signal in the frequency domain using an integrator transfer function. The second transform unit 640 converts the HEMP electric field strength signal of the frequency domain for which the compensation is completed into an HEMP field strength signal of the time domain by using an inverse Fourier transform technique (IFFT). can The second compensator 650 may compensate for signal strength according to a differential sensor constant, a dielectric constant, a balun attenuation value, and an integrator time constant.

Hereinafter, a HEMP measurement method performed by the HEMP measurement apparatus will be described.

6 is a flowchart illustrating a HEMP measurement method using a HEMP measurement apparatus according to an embodiment, FIG. 7 is a graph comparing frequency response characteristics according to integrator time constants, and FIG. 8 is an integral waveform distorted by oscilloscope noise. This is the graph shown.

Referring to FIG. 6 , the HEMP measurement method according to the embodiment may perform the step of collecting the HEMP electric field strength signal in the time domain through the optical data link ( S100 ).

An equation according to the HEMP electric field strength signal is the same as Equation 1. In this case, R _s is the impedance value connected to the sensor output terminal, A _eq is the equivalent area of the sensor, and D is the electric displacement.

[Equation 1]

The HEMP measuring method according to the embodiment may perform the step of converting the HEMP electric field strength signal in the time domain into a HEMP electric field strength signal in the frequency domain by using a Fourier transform technique (FFT) ( S200 ).

Equation 1 is transformed into an equation in the frequency domain using a Fourier transform, for example, a Laplace transform (s=jw), and v(s) is summarized as in Equation 2.

[Equation 2]

The HEMP measuring method according to the embodiment may perform the step of compensating for the HEMP electric field strength signal in the frequency domain using an integrator transfer function ( S300 ).

The integrator transfer function is expressed in Laplace form as in Equation 3. In this case, R _i C _i corresponds to the time constant of the integrator.

[Equation 3]

The relationship between input and output on the whole system according to signal transmission in the time domain is a convolution type, so data processing is quite difficult, but in the frequency domain expression, it is expressed as a product of the transmission function of each measuring device. If the differential signal in the frequency domain converted using this feature is multiplied by the transfer function of the virtual integrator, the signal to which the integrator is applied is compensated. At this time, as long as an appropriate time constant value is set, signals in DC and ultra-low frequency bands are not integrated, and since integration is performed only in bands higher than that, distortion such as biasing of the compensated signal does not occur.

_{That is, if the integrator transfer function formula is simplified by applying the condition of wR i} C _i >> 1 to Equation 3, the output voltage appears in the form of an integral of the input voltage, and the magnitude of the voltage is the time constant (R _i C _i ) of the integrator. It can be seen that it is inversely proportional. However, it does not operate as an integrator in a low frequency band that does not satisfy the condition of _{wR i} C _{i >> 1.} According to the US military specification MIL-STD-461G, in _{order to satisfy the condition of wR i} C _i >> 1 for the HEMP signal, it is suggested that the time constant of the integrator should be about 10 times the entire pulse width of the HEMP waveform. Looking at the waveform of FIG. 1, it can be seen that the HEMP whole pulse width is about 100 ns, and it can be seen that an integrator having a time constant of 1us or more, which is 10 times this value, can be used to properly measure. When looking at the frequency response of the entire measurement system (differential detector + integrator), the time constant of the integrator is the start frequency for a flat section (a signal can be measured without distortion in the section) and the magnitude response of the flat section, that is, the intensity of the output signal. decide As shown in FIG. 7 , as the time constant of the integrator increases, the start frequency for a flat section decreases, and the magnitude response of the corresponding section decreases.

The HEMP measuring method according to the embodiment converts the HEMP electric field strength signal in the frequency domain to the HEMP electric field strength signal in the time domain by using an inverse Fourier transform technique (IFFT) for the HEMP electric field strength signal in the frequency domain for which the compensation is completed. Step S400 may be performed.

는 자유 공간에서의 유전율을 의미한다.The HEMP electric field strength signal in the time domain may be defined by FIGS. 4 and 5 . Equation 4 may be an expression calculated by using an inverse Fourier transform technique on a value of the product of Equations 2 and 3 . A constant representing the degree of attenuation by the balun is reflected in Equation 4, and the constant representing the degree of attenuation by the balun may be expressed as b.

is the permittivity in free space.

[Equation 4]

Equation 5 is a summary of Equation 4 for E(t).

[Equation 5]

The HEMP measuring method according to the embodiment may perform the step of compensating for signal strength according to the differential sensor constant, the dielectric constant, the balun attenuation value, and the integrator time constant ( S500 ).

According to Equation 5 in the time domain, if the differential sensor constant (equivalent area and sensor impedance), dielectric constant, BALUN attenuation value, and the time constant of the integrator are compensated for in the same way as in the conventional method, a compensated signal without distortion in the time domain is obtained this is done

That is, in the case of the measurement system using the optical data link according to the embodiment, the signal input to the oscilloscope corresponds to the differential signal measured through the differential sensor. _{Previously, when the wR i} C _i >> 1 approximation was applied to the transfer function of the hardware integrator, we looked at the integration operation in the time domain. Therefore, it is expected that if integration in the time domain is performed on the differential signal shown on the oscilloscope, it will be simply compensated. However, the differential signal shown on the actual oscilloscope contains noise in the very low frequency band including the DC offset of the oscilloscope. Therefore, when numerical integration is simply performed on the signal shown on the oscilloscope, distortion occurs in which the shape of the integrated waveform is inclined to one side as shown in FIG. 8 . This is consistent with the fact that when a constant is integrated, it becomes a linear function and a slope occurs. Due to this issue, in the case of a measurement system using an optical transmission system, compensation through a transmission function in the frequency domain to which an approximation such as Equation 3 is not applied, rather than a simple numerical integration, is required. Since the transfer function in the frequency domain to which the approximation of Equation 3 is not applied has a low frequency blocking effect, it is possible to remove noise in the very low frequency band including the DC offset of the oscilloscope. In addition, in the case of a hardware integrator, the frequency domain to be integrated is already determined according to a predetermined time constant value, and accordingly, a flat section and a measurement dynamic range in the frequency magnitude response characteristic of the entire measurement system are determined. However, when using the virtual integrator transfer function in software, it is free in adjusting the time constant value of the integrator because it is not limited by the dynamic range. Accordingly, it is possible to perform integration only for a band higher than that without integrating with respect to the noise in the very low frequency band including DC, and it is possible to minimize the distortion of the measurement waveform due to the integration.

Various embodiments of this document are software (eg, a machine-readable storage media) (eg, a memory (internal memory or external memory)) including instructions stored in a readable storage medium (eg, a computer). : program) can be implemented. The device is a device capable of calling a stored command from a storage medium and operating according to the called command, and may include the electronic device according to the disclosed embodiments. When the command is executed by the control unit, the control unit may perform a function corresponding to the command directly or using other components under the control of the control unit. Instructions may include code generated or executed by a compiler or interpreter. The device-readable storage medium may be provided in the form of a non-transitory storage medium. Here, non-transitory means that the storage medium does not include a signal and is tangible, and does not distinguish that data is semi-permanently or temporarily stored in the storage medium.

According to an embodiment, the method according to various embodiments disclosed in the present document may be included and provided in a computer program product.

According to an embodiment, a computer-readable recording medium storing a computer program, comprising the steps of: collecting a HEMP electric field strength signal in a time domain through an optical data link; FFT) to convert the HEMP electric field strength signal in the frequency domain, compensating for the HEMP electric field strength signal in the frequency domain using an integrator transfer function, and the HEMP electric field strength signal in the frequency domain for which the compensation is completed converting the HEMP electric field strength signal in the frequency domain into a HEMP electric field strength signal in the time domain using an inverse Fourier transform technique (IFFT); and may include instructions for causing the processor to perform a method including an operation for performing the step of compensating for .

According to an embodiment, as a computer program stored in a computer-readable recording medium, the steps of collecting a HEMP electric field strength signal in a time domain through an optical data link, and a Fourier transform method ( FFT) to convert the HEMP electric field strength signal in the frequency domain, compensating for the HEMP electric field strength signal in the frequency domain using an integrator transfer function, and the HEMP electric field strength signal in the frequency domain for which the compensation is completed converting the HEMP electric field strength signal in the frequency domain into a HEMP electric field strength signal in the time domain using an inverse Fourier transform technique (IFFT); and may include instructions for causing the processor to perform a method including an operation for performing the step of compensating for .

Although the above has been described with reference to the drawings and embodiments, it will be understood by those skilled in the art that various modifications and changes can be made to the embodiments without departing from the spirit of the embodiments described in the claims below. will be able

100: differential sensor
200: balun
300: photoelectric conversion transmitter
400: photoelectric conversion receiver
500: oscilloscope
600: HEMP measuring device

Claims (10)

collecting HEMP electric field strength signals in the time domain through an optical data link;
converting the HEMP electric field strength signal in the time domain into a HEMP electric field strength signal in the frequency domain using a Fourier transform technique (FFT);
compensating for the HEMP electric field strength signal in the frequency domain using an integrator transfer function; and
converting the HEMP electric field strength signal of the frequency domain for which the compensation is completed into an HEMP electric field strength signal of the time domain using an inverse Fourier transform technique (IFFT); and
Compensating for signal strength according to differential detector constant, dielectric constant, balun attenuation value, and integrator time constant
HEMP measurement method using an optical data link system comprising a. According to claim 1,
Compensating for the HEMP electric field strength signal in the frequency domain is a HEMP measurement method using an optical data link system in which the HEMP electric field strength signal in the frequency domain is multiplied by the integrator transfer function. According to claim 1,
In the step of collecting the HEMP electric field strength signal in the time domain, the HEMP electric field strength signal in the time domain is expressed by Equation (1).
[Equation 1]

(Here, R _s is the impedance value connected to the sensor output terminal, A _eq is the equivalent area of the sensor, and D is the electric displacement.) 4. The method of claim 3,
In the step of converting the HEMP electric field strength signal in the frequency domain, the HEMP electric field strength in the frequency domain is expressed by Equation (2).
[Equation 2]

5. The method of claim 4,
The integrator transfer function is a HEMP measurement method using an optical data link system expressed by Equation (3).
[Equation 3]

(Here, R _i C _i means the time constant of the integrator.) 6. The method of claim 5,
In the step of converting the HEMP electric field strength signal in the time domain, the HEMP electric field strength signal in the time domain is expressed by Equation (4).
[Equation 4]

(here, b means a constant indicating the degree of attenuation by the balun,

is the permittivity in free space.) 7. The method of claim 6,
Compensating the signal strength according to the differential sensor constant, the dielectric constant, the balun attenuation value, and the integrator time constant is calculated by Equation (5).
[Equation 5]

a collection unit that collects HEMP electric field strength signals in the time domain through an optical data link;
a first transform unit for converting the HEMP electric field strength signal in the time domain into a HEMP electric field strength signal in the frequency domain using a Fourier transform technique (FFT);
a first compensator for compensating the HEMP electric field strength signal in the frequency domain using an integrator transfer function; and
a second transform unit converting the HEMP electric field strength signal of the frequency domain for which the compensation is completed into an HEMP electric field strength signal of the time domain by using an inverse Fourier transform technique (IFFT); and
A second compensator compensating for signal strength according to the differential detector constant, the dielectric constant, the balun attenuation value, and the integrator time constant
HEMP measurement apparatus using an optical data link system comprising a. As a computer-readable recording medium storing a computer program,
The computer program is
collecting HEMP electric field strength signals in the time domain through an optical data link;
converting the HEMP electric field strength signal in the time domain into a HEMP electric field strength signal in the frequency domain using a Fourier transform technique (FFT);
compensating for the HEMP electric field strength signal in the frequency domain using an integrator transfer function;
converting the HEMP electric field strength signal of the frequency domain for which the compensation is completed into an HEMP electric field strength signal of the time domain using an inverse Fourier transform technique (IFFT); and
A computer-readable recording medium comprising instructions for causing a processor to perform an operation for performing the step of compensating for signal strength according to a differential sensor constant, a dielectric constant, a balun attenuation value, and an integrator time constant. As a computer program stored in a computer-readable recording medium,
The computer program is
collecting HEMP electric field strength signals in the time domain through an optical data link;
converting the HEMP electric field strength signal in the time domain into a HEMP electric field strength signal in the frequency domain using a Fourier transform technique (FFT);
compensating for the HEMP electric field strength signal in the frequency domain using an integrator transfer function;
converting the HEMP electric field strength signal of the frequency domain for which the compensation is completed into an HEMP electric field strength signal of the time domain using an inverse Fourier transform technique (IFFT); and
A computer program comprising instructions for causing the processor to perform an operation for compensating for signal strength according to a differential detector constant, a dielectric constant, a balun attenuation value, and an integrator time constant.

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