A time-domain measurement method for the field strength of a repetitive frequency-varying or frequency-hopping pulse signal radiation field

Abstract

The present invention discloses a time-domain measurement method for the field strength of a repetitive frequency change or frequency hopping pulse signal radiation field, which relates to the field of radio frequency radiation field electric field measurement. In the method of the present invention, first, the triggering mode of the time-domain measurement device is set to pulse width triggering, and time-domain parameters including pulse voltage amplitude measurement readings are measured; then, according to the modulation form of the repetitive frequency change or frequency hopping pulse signal and time-domain parameters such as pulse width, an analog periodic pulse signal is constructed; then, the field strength correction coefficient is determined by using the parameters of the analog periodic pulse signal; finally, according to the field strength correction coefficient and the pulse voltage amplitude measurement readings, the field strength of the repetitive frequency change or frequency hopping pulse signal radiation field is calculated. This method is not affected by the random change of repetitive frequency or carrier frequency, can accurately measure the peak field strength and average field strength, can identify the radiation source, and is easy to be popularized and used.

Description

Technical Field

[0001] The present invention relates to the field of radio frequency radiation field electric field measurement, and particularly to a time-domain measurement method for the field strength of a radiation field of a pulse signal with variable repetition frequency or frequency hopping. Background Art

[0002] A strong pulsed radio frequency radiation field affects the normal operation of frequency-using devices, and electromagnetic environment adaptability verification tests should be carried out. During the tests, in order to distinguish the electromagnetic environment background of the test area and eliminate the influence of external electromagnetic radiation sources, the applied pulsed radiation field should be monitored to ensure that the frequency-using device is in a pulsed radiation field with a specified radiation waveform and specified energy, so as to ensure the effectiveness and credibility of the test results.

[0003] Different waveforms have different interference effects on frequency-using devices, and it is necessary to irradiate the frequency-using devices with actual radiation waveforms. Pulse signals with variable repetition frequency or frequency hopping, including signals with sliding repetition frequency, jittered repetition frequency, staggered repetition frequency, inter-pulse frequency hopping pulse signals, and pulse-group frequency hopping pulse signals, are one of the strong electromagnetic fields that frequency-using devices may face. Therefore, it is necessary to clarify the measurement methods for the radiation fields of pulse signals with variable repetition frequency and frequency hopping.

[0004] The currently commonly used radiation field measurement methods are as follows:

[0005] (1) Measuring with an electric field probe

[0006] Electric field probes are often used to measure periodic pulsed radiation fields and can provide the field strength amplitude, but there are limitations in their use: First, for a radiation field with variable repetition frequency, since the pulse repetition frequency changes randomly, the electric field probe cannot obtain stable measurement results, so the electric field probe is not applicable. Second, it cannot provide frequency information or waveform characteristic information of the pulsed radiation field, cannot identify the radiation source, and cannot determine whether the measured field strength is generated by the specified radiation source, and cannot distinguish whether the tested frequency-using device is in the specified radiation field. The test verification is usually carried out in the external field, and there may be unknown radiation sources, and their radiation is not subject to the management of the verification test. Using an electric field probe may mistake the radiation field generated by an external radiation source for the one generated by the verification test, resulting in untrustworthy test results.

[0007] (2) Measuring with an antenna and a spectrum measurement device

[0008] By using a spectrum measurement device such as a spectrum analyzer or a measurement receiver, the frequency information of the radiation field can be obtained, thereby enabling the identification of the radiation source. However, when the measurement resolution bandwidth is less than the occupied bandwidth of the radiation field signal, the existing frequency-domain measurement methods cannot provide accurate measurement results. Especially for a pulsed radiation field with a changing pulse repetition frequency, when measuring with a spectrum measurement device, there is still a lack of research on how to obtain a stable measurement value with clear physical meaning and achieve accurate measurement of the peak field strength and average field strength. For a radiation field of a frequency-hopping pulse signal, at each frequency-hopping frequency, the measurement by the spectrum measurement device is equivalent to measuring a pulsed radiation field with a changing pulse repetition frequency. There is also a lack of research on how to accurately measure the peak field strength and average field strength, and no relevant reports have been seen.

[0009] The patent application "A Method and Device for Measuring the Field Strength of a Modulated Signal" (Application No. 201210342072.5) proposes to develop a dedicated device. By calculating the power spectrum of the sampled signal and integrating to obtain the power of the modulated radiation signal, and then calculating the field strength of the radiation field. However, it does not give a specific method on how to control the waveform of the intercepted sampled signal to make it representative of the measured radiation signal. There are no requirements for the length and position of the interception time, and these parameters that are very important for field strength calculation are not specified. It can be seen that the field strength result calculated by this method has a very large deviation from the actual situation. In addition, there are the following problems: ① For a pulsed signal with a staggered pulse repetition frequency, a pulsed signal with a jittered pulse repetition frequency, and a pulsed signal with a sliding pulse repetition frequency, stable values cannot be measured, and it is difficult to measure the field strength value; ② The RF bandwidth of the dedicated device cannot be modified. According to the technical solution of the dedicated device, the measurement bandwidth during measurement is already fixed. Therefore, it can only be used to measure a radiation field with an occupied bandwidth less than the measurement bandwidth of the dedicated device. When the occupied bandwidth of the radiation field signal is greater than the RF bandwidth of the dedicated device, accurate results cannot be measured by this dedicated device, and various dedicated devices with different bandwidths need to be developed and produced according to the occupied spectrum of the measured radiation field.

[0010] Compared with periodic pulsed signals, it is more difficult to measure the radiation field of pulsed signals with a changing pulse repetition frequency or frequency-hopping. How to determine whether the device under test is indeed in a pulsed radiation field with a specified radiation waveform and specified energy is a new technical problem, lacking technical information for reference, and there is currently a lack of measurement methods.

[0011] How to obtain a measurement method with good engineering practical value and good generality, which can simply and accurately measure the peak field strength and average field strength of the radiation field of pulsed signals with a changing pulse repetition frequency or frequency-hopping, is not restricted by random changes in the pulse repetition frequency and carrier frequency, and can identify the radiation source, is the technical problem solved by the present invention. Summary of the Invention

[0012] The object of the present invention is to provide a method for measuring the field strength in the time domain for the radiation fields of various repetitive frequency change or frequency hopping pulse signals. By using existing or potentially developed time domain measuring devices, it solves the problem that it is difficult to obtain stable measurement results in time domain measurement due to the random change of repetitive frequency or carrier frequency, and can identify the radiation source. The measurement results of this method are accurate, the measurement speed is fast, it is simple and feasible, and it is easy to promote and use, providing accurate and objective technical parameters for the electromagnetic environment adaptability verification test of frequency-using equipment in strong pulse radiation fields.

[0013] The object of a method for measuring the field strength in the time domain of a repetitive frequency change or frequency hopping pulse signal radiation field according to the present invention is achieved through the following steps:

[0014] Step 1: Set the triggering mode of the time domain measuring device to pulse width triggering, measure the repetitive frequency change or frequency hopping pulse signal, and obtain the time domain parameters including the pulse voltage amplitude.

[0015] Step 2: Construct an analog periodic pulse signal according to the time domain parameters of the repetitive frequency change or frequency hopping pulse signal. The time domain parameters include modulation form, modulation parameters, pulse width, pulse repetition frequency, and carrier frequency.

[0016] Step 3: Determine the field strength correction coefficient by using the parameters of the analog periodic pulse signal.

[0017]

[0018] A is the characterization of the pulse voltage amplitude of the analog periodic pulse signal;

[0019] k os is the field strength correction coefficient of the repetitive frequency change or frequency hopping pulse signal radiation field, which is the peak field strength correction coefficient of the repetitive frequency change or frequency hopping pulse signal radiation field (abbreviated as peak field strength correction coefficient), or the average field strength correction coefficient of the repetitive frequency change or frequency hopping pulse signal radiation field (abbreviated as average field strength correction coefficient);

[0020] P is the power of the analog periodic pulse signal, which is the peak power or average power. When P represents the peak power, k os is the peak field strength correction coefficient. When P represents the average power, k os is the average field strength correction coefficient.

[0021] Step 4: Calculate the field strength of the repetitive frequency change or frequency hopping pulse signal radiation field according to the field strength correction coefficient and the measured reading of the pulse voltage amplitude.

[0022] The design concept of the present invention is to set the triggering mode of the time-domain measurement device to pulse-width triggering, which can screen out the pulse-width conforming to the characteristics of the measured signal in the radiation field with other pulses, obtain stable triggering, and thus obtain stable measurement results, solve the problem that it is difficult to obtain stable measurement results due to the change of pulse repetition frequency or carrier frequency in time-domain measurement, and exclude the interference of other pulse signals, identify the radiation source, and ensure that the measurement results are generated by the specified radiation source. Then, try to establish the mathematical relationship between the field strength of the radiation field and the amplitude of the pulse voltage, and obtain the field strength correction coefficient. In this way, according to the measured reading of the pulse voltage amplitude and the field strength correction coefficient, the field strength of the radiation field can be obtained.

[0023] The following elaborates in detail the more optimized technical solutions for each step.

[0024] Preferably, the pulse-width triggering range set in step one is less than 2 times the pulse width of the pulse-repetition-frequency change or frequency-hopping pulse signal, that is, when the pulse width is less than 2 times the pulse width of the pulse-repetition-frequency change or frequency-hopping pulse signal, the time-domain measurement device is triggered.

[0025] Preferably, the pulse-width triggering range in step one is 0.8 to 1.2 times the pulse width of the pulse-repetition-frequency change or frequency-hopping pulse signal, that is, when the pulse width falls within the range greater than 0.8 times the pulse width of the pulse-repetition-frequency change or frequency-hopping pulse signal and less than 1.2 times (including), the time-domain measurement device is triggered.

[0026] When the signal triggered on the time-domain measurement device is unstable, the pulse-width triggering range can be further reduced.

[0027] Setting the triggering pulse width in this way can meet the actual pulse-width change range of most transmitting devices, ensure the practicability of the measurement method, and more accurately screen out the pulse-repetition-frequency change or frequency-hopping pulse signal.

[0028] When the occupied bandwidth of the measured pulse-repetition-frequency change or frequency-hopping pulse signal is greater than the radio-frequency bandwidth of the time-domain measurement device, an envelope detector can be used to detect the measured pulse signal before the time-domain measurement device, and then send it to the time-domain measurement device for measurement.

[0029] The input impedance of the time-domain measurement device is set to 50 ohms; for a time-domain measurement device with a high input impedance, a 50-ohm impedance matcher can be connected to the input end.

[0030] For the pulse-repetition-frequency change pulse signal, measure and record the pulse voltage amplitude; for the frequency-hopping pulse signal, measure and record the pulse voltage amplitude and the pulse repetition frequency.

[0031] In this way, the pulse voltage amplitude and the pulse repetition frequency of the frequency-hopping pulse signal are obtained, providing an input for constructing an analog periodic pulse signal for use in calculating the field strength.

[0032] Step 2. The time-domain parameters for constructing the simulated periodic pulse signal include the modulation form, modulation parameters, pulse width, carrier frequency, pulse repetition frequency, etc. of the pulse signal with changing PRF or frequency-hopping pulse signal. The further optimization schemes for each time-domain parameter are as follows:

[0033] Preferably, the modulation form of the simulated periodic pulse signal is the same as that of the measured pulse signal with changing PRF or frequency-hopping pulse signal.

[0034] Preferably, the modulation parameters and pulse width of the simulated periodic pulse signal are respectively equal to the modulation parameters and pulse width of the measured pulse signal with changing PRF or frequency-hopping pulse signal.

[0035] Preferably, for the pulse signal with changing PRF, the carrier frequency of the simulated periodic pulse signal is equal to the carrier frequency of the pulse signal with changing PRF; for the frequency-hopping pulse signal, the carrier frequency of the simulated periodic pulse signal is any one of the hopping carrier frequencies of the frequency-hopping pulse signal.

[0036] Preferably, the determination of the pulse repetition frequency varies depending on the type of the pulse signal with changing PRF or frequency-hopping pulse signal:

[0037] 1) For the pulse signal with jittering PRF or sliding PRF, the method for determining the pulse repetition frequency of the simulated periodic pulse signal is as follows,

[0038] f av =f even (1)

[0039] f av is the pulse repetition frequency of the simulated periodic pulse signal;

[0040] f even is the center of the pulse repetition frequency range of the pulse signal with jittering PRF or sliding PRF, which is a known quantity.

[0041] 2) For the pulse signal with staggered PRF, the method for determining the pulse repetition frequency of the simulated periodic pulse signal is as follows,

[0042]

[0043] f av is the pulse repetition frequency of the simulated periodic pulse signal;

[0044] f m is the m-th pulse repetition frequency of the pulse signal with staggered PRF, which is a known quantity;

[0045] p m is the probability that the pulse signal with staggered PRF appears at the m-th pulse repetition frequency, which is a known quantity;

[0046] N is the total number of the pulse repetition frequencies of the pulse signal with staggered PRF, which is a known quantity.

[0047] 3) For a frequency-hopping pulse signal, the pulse repetition frequency of the simulated periodic pulse signal is equal to that of the measured frequency-hopping pulse signal to be measured.

[0048] The advantages of designing the modulation form, modulation parameters, pulse width, carrier frequency, and pulse repetition frequency of the simulated periodic pulse signal in this way are that the characterization of the peak power and average power of the simulated periodic pulse signal is the same as that of the measured pulse signal, and the magnitude relationship is also the same. This is beneficial for simplifying the calculation of the peak power and average power of the measured PRF change or frequency-hopping pulse signal by using the periodicity of the simulated periodic pulse signal.

[0049] Preferably, in step 3, the characterization of the power of the simulated periodic pulse signal is achieved through theoretical derivation of the parameters of the simulated periodic pulse signal in the time domain or frequency domain.

[0050] Preferably, in step 3, the field strength correction coefficient is determined by using the simulation result of the power of the simulated periodic pulse signal.

[0051]

[0052] A sim The given value of the pulse voltage amplitude of the simulated periodic pulse signal during simulation; k os The field strength correction coefficient of the PRF change or frequency-hopping pulse signal, which is the peak field strength correction coefficient of the PRF change or frequency-hopping pulse signal radiation field, or the average value field strength correction coefficient of the PRF change or frequency-hopping pulse signal radiation field; P sim Is the simulation result of the power of the simulated periodic pulse signal. When P sim Represents the simulation result of the peak power, k os Is the peak field strength correction coefficient. When P sim Represents the simulation result of the average power, k os Is the average value field strength correction coefficient.

[0053] Preferably, for the radiation field of a PRF change or frequency-hopping pulse signal with a pulse unit being a phase-coded pulse or a frequency-coded pulse, the peak field strength correction coefficient is

[0054] Preferably, for the radiation field of a PRF change or frequency-hopping pulse signal with a pulse unit being an ultra-wideband linear frequency modulation pulse, the peak field strength correction coefficient is

[0055]

[0056] Where k os_p : Peak field strength correction coefficient;

[0057] d: Time-bandwidth product, that is, the product of the signal occupied bandwidth and the pulse width (for example, see page 139 of "Fundamentals of Radar Signal Processing" translated by Xing Mengdao, etc.).

[0058] z: broadband index, which is the ratio of the carrier frequency to the signal occupancy bandwidth;

[0059] S(·): Fresnel sine integral;

[0060] C(·): Fresnel cosine integral.

[0061] Specifically, for the radiation field of a repetitive frequency change or frequency hopping pulse signal with the pulse unit being an ultra-wideband chirp pulse and the time-bandwidth product being 1, the peak field strength correction coefficient is

[0062] When z ∈ [0.554, 0.903], k os_p = 0.05cos(2π * 1.45 * z + 2.83) + 0.7;

[0063] When z ∈ [1.089, 1.395], k os_p = 0.04cos(2π * 1.6 * z + 0.18) + 0.7;

[0064] When z ∈ [1.538, 1.937], k os_p = -0.023cos(2π * 2.51 * z - 0.618) + 0.71;

[0065] When z ∈ [2.05, 2.425], k os_p = 0.02cos(2π * 3z + 0.372) + 0.71;

[0066] When z ∈ [2.54, 2.92], k os_p = -0.012cos(2π * 2.969 * z + 2.302) + 0.708;

[0067] When z ∈ [3.035, 3.458], k os_p = -0.01cos(2π * 3.9 * z + 2.22) + 0.706;

[0068] When z ∈ [3.598, 3.896], k os_p = 0.01cos(2π * 4.8 * z + 1.8) + 0.707;

[0069] When z is other values,

[0070] Specifically, for the radiation field of a repetitive frequency change or frequency hopping pulse signal with the pulse unit being an ultra-wideband chirp pulse and the time-bandwidth product being 2, the peak field strength correction coefficient is

[0071] When z ∈ [0.516, 0.758], k os_p= -0.019cos(2π×3.53×z - 0.175) + 0.7;

[0072] When z ∈ [0.767, 0.97], k os_p = 0.037cos(2π×1.76×z - 3.313) + 0.69;

[0073] When z ∈ [1.026, 1.218], k os_p = 0.01cos(2π×5z - 0.66) + 0.7;

[0074] When z ∈ [1.27, 1.498], k os_p = -0.011cos(2π×3.96×z + 1.312) + 0.71;

[0075] When z ∈ [1.507, 1.715], k os_p = -0.012cos(10π×z + 1.7) + 0.71;

[0076] When z ∈ [1.777, 1.962], k os_p = -0.011cos(2π×5.3×z + 2.13) + 0.71;

[0077] When z ∈ [2.03, 2.216], k os_p = 0.01cos(2π×5.7×z - 2.11) + 0.71;

[0078] When z ∈ [2.267, 2.464], k os_p = 0.009cos(2π×6×z - 2.23) + 0.71;

[0079] When z ∈ [2.542, 2.714], k os_p = 0.009cos(2π×6.9×z + 0.15) + 0.71;

[0080] When z ∈ [2.767, 2.974], k os_p = 0.007cos(2π×7.8×z + 0.57) + 0.71;

[0081] When z is other values,

[0082] Specifically preferably, for the radiation field of the pulse unit being an ultra-wideband linear frequency modulation pulse and the pulse repetition frequency change or frequency hopping pulse signal with a time-bandwidth product greater than 2, the peak field strength correction coefficient is

[0083] Preferably, in step three, according to formula (5), the average field strength correction coefficient and the peak field strength correction coefficient k os_p are converted to each other

[0084]

[0085] k os_a : the average field strength correction coefficient of the radiation field of the pulse signal with variable repetition frequency or frequency hopping;

[0086] k os_p : the peak field strength correction coefficient of the radiation field of the pulse signal with variable repetition frequency or frequency hopping;

[0087] f av : the pulse repetition frequency of the simulated periodic pulse signal;

[0088] τ: the pulse width of the simulated periodic pulse signal.

[0089] Preferably, in step four, calculate the peak field strength of the radiation field of the pulse signal with variable repetition frequency or frequency hopping

[0090]

[0091]

[0092] In the formula,

[0093] E p : the peak field strength of the radiation field of the pulse signal with variable repetition frequency or frequency hopping, referred to as the peak field strength, unit V / m;

[0094] E a : the average field strength of the radiation field of the pulse signal with variable repetition frequency or frequency hopping, referred to as the average field strength, unit V / m;

[0095] k os_a : the average field strength correction coefficient of the radiation field of the pulse signal with variable repetition frequency or frequency hopping;

[0096] k os_p : the peak field strength correction coefficient of the radiation field of the pulse signal with variable repetition frequency or frequency hopping;

[0097] k detector : the coefficient of the envelope detector, take 1 when the envelope detector is not used;

[0098] A r is the measured reading of the pulse voltage amplitude, unit V;

[0099] F A : the antenna coefficient, unit dB / m;

[0100] F D : the total attenuation of the attenuator and the connecting cable, unit dB.

[0101] According to Equation (8), the average field strength E a and the peak field strength E p can also be converted into each other

[0102]

[0103] The rest of the measurement method belongs to common knowledge and will not be described

[0104] The present invention has achieved the following beneficial effects

[0105] 1. By setting the pulse width trigger and trigger range, the problem that it is difficult to obtain stable measurement results in time domain measurement due to the change of pulse repetition frequency or carrier frequency is solved, and the pulse repetition frequency change or frequency hopping pulse signal to be measured can be screened out in the radiation field with other pulses, excluding the interference of other pulse signals, and the beneficial effects of capturing stable measurement values and identifying radiation sources are achieved

[0106] 2. Wide application range. The pulse repetition frequency change pulse signals applicable to the radiation field include pulse repetition frequency sliding pulse signals, pulse repetition frequency jitter pulse signals, and pulse repetition frequency stagger pulse signals; the frequency hopping pulse signals in the radiation field include inter-pulse frequency hopping signals and pulse group frequency hopping signals. The pulse unit forms of the pulse repetition frequency change or frequency hopping pulse signals include linear frequency modulation signals, non-linear frequency modulation signals, intra-pulse frequency encoding signals, phase encoding signals, rectangular pulse modulation signals, and ultra-wideband linear frequency modulation pulse signals

[0107] 3. The measurement can be completed by using a widely common oscilloscope, without the need to develop a dedicated measurement device, which is simple and feasible, and has engineering practical value and popularization and application value

[0108] 4. By calculating the power of the pulse signal to be measured or deriving the expression, the influence of the modulation characteristics of the radiation signal is solved; the oscilloscope and the antenna have fast response speeds, and the measurement is not affected by the response time BRIEF DESCRIPTION OF THE DRAWINGS

[0109] Figure 1 Schematic diagram of the measurement steps of the present invention

[0110] Figure 2 Peak field strength correction coefficient of the radiation field of the pulse repetition frequency change or frequency hopping pulse signal with the pulse unit being an ultra-wideband linear frequency modulation pulse and the time-bandwidth product being 1 DETAILED DESCRIPTION OF THE INVENTION

[0111] In order to make the purpose, technical solution and advantages of the present invention clearer, the following further describes the present invention in detail with reference to the preferred embodiments and the attached Figure 1 to the attached Figure 2 drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention

[0112] Throughout the present text, including the embodiments, the following names and their abbreviations are set and commonly used. It should be noted that those skilled in the art should understand that, without departing from the principles and essence of the present invention, various changes or modifications can be made to these names, abbreviations, and letter codes, but such changes and modifications all fall within the protection scope of the present invention. Unless otherwise specified, all symbols and codes adopt the International System of Units.

[0113] A Pulse voltage amplitude of the analog periodic pulse signal;

[0114] A r Measured reading of the pulse voltage amplitude, unit: V;

[0115] A sim Given value of the pulse voltage amplitude of the analog periodic pulse signal during simulation;

[0116] d: Time-bandwidth product, that is, the product of the signal occupancy bandwidth and the pulse width;

[0117] E p Peak field strength of the radiation field of the PRF-varying or frequency-hopping pulse signal, unit: V / m;

[0118] E a Average field strength of the radiation field of the PRF-varying or frequency-hopping pulse signal, unit: V / m;

[0119] f av Pulse repetition frequency of the analog periodic pulse signal;

[0120] f even Center of the pulse repetition frequency range of the PRF-jittering or PRF-sliding pulse signal;

[0121] f m The m-th pulse repetition frequency of the PRF-staggered pulse signal;

[0122] F A Antenna coefficient, unit: dB / m;

[0123] F D Total attenuation of the attenuator and the connecting cable, unit: dB;

[0124] k detector Coefficient of the envelope detector, taking 1 when the envelope detector is not used;

[0125] k os Field strength correction coefficient for the radiation field of the PRF-varying or frequency-hopping pulse signal (abbreviation: field strength correction coefficient);

[0126] k os_a Average field strength correction coefficient for the radiation field of the PRF-varying or frequency-hopping pulse signal (abbreviation: average field strength correction coefficient);

[0127] k os_p Correction coefficient of peak field strength of repetitive frequency varying or frequency hopping pulse signal (hereinafter referred to as peak field strength correction coefficient);

[0128] m: natural number;

[0129] Total number of pulse repetition frequencies of N - repetitive frequency staggered pulse signal;

[0130] p m Probability that the m - th pulse repetition frequency appears in the repetitive frequency staggered pulse signal;

[0131] P: Power of simulated periodic pulse signal;

[0132] P sim Simulation result of power of simulated periodic pulse signal;

[0133] z: Wide - band index, which is the ratio of carrier frequency to signal occupied bandwidth;

[0134] τ: Pulse width of repetitive frequency varying or frequency hopping pulse signal.

[0135] S(·): Fresnel sine integral;

[0136] C(·): Fresnel cosine integral.

[0137] Preferred embodiment

[0138] The implementation steps of the present invention are as Figure 1 shown.

[0139] Combined Figure 1 , it can be seen the complete technical solution of the present invention: A time - domain measurement method for the field strength of repetitive frequency varying or frequency hopping pulse signal radiation field, including the following steps: 1) Step 1: Set the trigger condition of the time - domain measurement device, measure the repetitive frequency varying or frequency hopping pulse signal, and read time - domain parameters such as pulse voltage amplitude; 2) Step 2: Construct a simulated periodic pulse signal; 3) Step 3: Calculate the field strength correction coefficient by using the pulse voltage amplitude and the power of the simulated periodic pulse signal; 4) Step 4: Calculate the field strength of the repetitive frequency varying or frequency hopping pulse signal radiation field according to the pulse voltage amplitude reading and the field strength correction coefficient.

[0140] The specific embodiments of each step are as follows.

[0141] In Step 1, set the triggering mode of the time-domain measurement device to pulse-width triggering. The pulse-width triggering range is less than twice the pulse width of the PRF change or FH pulse signal, that is, when the pulse width is less than twice the pulse width of the PRF change or FH pulse signal, the time-domain measurement device is triggered. Among them, a better pulse-width triggering range is greater than 0.8 times and less than 1.2 times the pulse width of the PRF change or FH pulse signal, that is, when the pulse width falls within the range of greater than 0.8 times and less than 1.2 times the pulse width of the PRF change or FH pulse signal, the time-domain measurement device is triggered. When the signal triggered on the time-domain measurement device is unstable, the pulse-width triggering range can be further reduced.

[0142] Connect the time-domain measurement device (such as an oscilloscope), an attenuator, and an antenna to measure the radiation field of the PRF change or FH pulse signal. When the occupied bandwidth of the measured PRF change or FH pulse signal is greater than the RF bandwidth of the time-domain measurement device, a envelope detector can be used to detect the measured pulse signal before the time-domain measurement device and then send it to the time-domain measurement device for measurement.

[0143] Set the input impedance of the time-domain measurement device to 50 ohms; for a time-domain measurement device with a high input impedance, a 50-ohm impedance matcher can be connected to the input end.

[0144] For the PRF change pulse signal, measure and record the pulse voltage amplitude; for the FH pulse signal, measure and record the pulse voltage amplitude and the pulse repetition frequency.

[0145] In Step 2, construct an analog periodic pulse signal according to the time-domain parameters of the PRF change or FH pulse signal. The time-domain parameters include modulation form, modulation parameters, pulse width, pulse repetition frequency, and carrier frequency.

[0146] Among them, the method for constructing the analog periodic pulse signal is as follows:

[0147] The time-domain parameters for constructing the analog periodic pulse signal include the modulation form, modulation parameters, pulse width, carrier frequency, and pulse repetition frequency of the radiation field signal, etc.

[0148] The modulation form of the analog periodic pulse signal is the same as that of the measured PRF change or FH pulse signal, and the modulation parameters and pulse width are respectively equal to the modulation parameters and pulse width of the measured PRF change or FH pulse signal.

[0149] For the PRF change pulse signal, the carrier frequency of the analog periodic pulse signal is equal to the carrier frequency of the PRF change pulse signal; for the FH pulse signal, the carrier frequency of the analog periodic pulse signal is any hopping carrier frequency of the FH pulse signal.

[0150] The method for determining the pulse repetition frequency is as follows:

[0151] 1) For the pulse signal with pulse repetition frequency jitter or pulse repetition frequency slip, the method for determining the pulse repetition frequency of the simulated periodic pulse signal is as follows:

[0152] f av = f even ; (1)

[0153] 2) For the pulse signal with staggered pulse repetition frequency, the method for determining the pulse repetition frequency of the simulated periodic pulse signal is as follows:

[0154]

[0155] 3) For the frequency-hopping pulse signal, the pulse repetition frequency of the simulated periodic pulse signal is equal to that of the measured frequency-hopping pulse signal.

[0156] In step three, the field strength correction coefficient of the pulse signal with changing pulse repetition frequency or frequency-hopping is determined by using the parameters of the simulated periodic pulse signal.

[0157]

[0158] Among them, the power of the simulated periodic pulse signal is characterized by theoretical derivation of the parameters of the simulated periodic pulse signal in the time domain or frequency domain.

[0159] In step three, the field strength correction coefficient is determined by using the power simulation result of the simulated periodic pulse signal.

[0160]

[0161] For the radiation field of the pulse signal with changing pulse repetition frequency or frequency-hopping whose pulse unit is a phase-coded pulse or a frequency-coded pulse, the peak field strength correction coefficient is

[0162] For the radiation field of the pulse signal with changing pulse repetition frequency or frequency-hopping whose pulse unit is an ultra-wideband linearly frequency-modulated pulse, the peak field strength correction coefficient curve is

[0163]

[0164] The above correction coefficients are a family of oscillating curves. For the convenience of engineering implementation, through numerical programming calculation, the following several cases are used for simplification.

[0165] Specifically, for the radiation field of the pulse signal with changing pulse repetition frequency or frequency-hopping whose pulse unit is an ultra-wideband linearly frequency-modulated pulse and the time-bandwidth product is 1, the peak field strength correction coefficient is shown in Appendix Figure 2 , simplified to

[0166] When z ∈ [0.554, 0.903], k os_p = 0.05cos(2π * 1.45 * z + 2.83) + 0.7;

[0167] When \(z\in[1.089,1.395]\), \(k\) os_p \( = 0.04\cos(2\pi\times1.6\times z + 0.18)+0.7\);

[0168] When \(z\in[1.538,1.937]\), \(k\) os_p \( = - 0.023\cos(2\pi\times2.51\times z - 0.618)+0.71\);

[0169] When \(z\in[2.05,2.425]\), \(k\) os_p \( = 0.02\cos(2\pi\times3z + 0.372)+0.71\);

[0170] When \(z\in[2.54,2.92]\), \(k\) os_p \( = - 0.012\cos(2\pi\times2.969\times z + 2.302)+0.708\);

[0171] When \(z\in[3.035,3.458]\), \(k\) os_p \( = - 0.01\cos(2\pi\times3.9\times z + 2.22)+0.706\);

[0172] When \(z\in[3.598,3.896]\), \(k\) os_p \( = 0.01\cos(2\pi\times4.8\times z + 1.8)+0.707\);

[0173] When \(z\) is other values,

[0174] In this way, the implementation of the work is greatly simplified.

[0175] Specifically, for the radiation field of a repetitive frequency change or frequency hopping pulse signal with an ultra-wideband linear frequency modulation pulse as the pulse unit and a time-bandwidth product of 2, the peak field strength correction coefficient is simplified to

[0176] When \(z\in[0.516,0.758]\), \(k\) os_p \( = - 0.019\cos(2\pi\times3.53\times z - 0.175)+0.7\);

[0177] When \(z\in[0.767,0.97]\), \(k\) os_p \( = 0.037\cos(2\pi\times1.76\times z - 3.313)+0.69\);

[0178] When \(z\in[1.026,1.218]\), \(k\) os_p \( = 0.01\cos(2\pi\times5z - 0.66)+0.7\);

[0179] When \(z\in[1.27,1.498]\), \(k\)os_p = -0.011cos(2π×3.96×z + 1.312) + 0.71;

[0180] When z ∈ [1.507, 1.715], k os_p = -0.012cos(10π×z + 1.7) + 0.71;

[0181] When z ∈ [1.777, 1.962], k os_p = -0.011cos(2π×5.3×z + 2.13) + 0.71;

[0182] When z ∈ [2.03, 2.216], k os_p = 0.01cos(2π×5.7×z - 2.11) + 0.71;

[0183] When z ∈ [2.267, 2.464], k os_p = 0.009cos(2π×6×z - 2.23) + 0.71;

[0184] When z ∈ [2.542, 2.714], k os_p = 0.009cos(2π×6.9×z + 0.15) + 0.71;

[0185] When z ∈ [2.767, 2.974], k os_p = 0.007cos(2π×7.8×z + 0.57) + 0.71;

[0186] When z is other values,

[0187] In this way, the implementation of the work is greatly simplified.

[0188] Specifically, for the radiation field of a PRF change or frequency hopping pulse signal with an ultra-wideband linear frequency modulation pulse as the pulse unit and a time-bandwidth product greater than 2, the peak field strength correction coefficient is

[0189] According to formula (5), the average field strength correction coefficient k os_a and the peak field strength correction coefficient k os_p can be converted into each other

[0190]

[0191] In step four, calculate the peak field strength of the PRF change or frequency hopping pulse signal radiation field

[0192]

[0193]

[0194] The average field strength E can also be converted according to Equation (8) a and the peak field strength E p into each other

[0195]

[0196] It can be seen that the present invention has achieved the following beneficial effects:

[0197] 1. By setting the pulse width trigger and the trigger range, the problem that it is difficult to obtain stable measurement results in time-domain measurement due to the change of the repetition frequency or the carrier frequency is solved, and it is possible to screen out the repetition frequency change or the frequency hopping pulse signal in the radiation field with other pulses, eliminate the interference of other pulse signals, and achieve the beneficial effects of capturing stable measurement values and identifying the radiation source.

[0198] 2. It has a wide range of applications. The repetition frequency change pulse signals in the radiation field include repetition frequency sliding signals, repetition frequency jitter signals, and repetition frequency staggering signals; the frequency hopping pulse signals in the radiation field include inter-pulse frequency hopping signals and pulse group frequency hopping signals; the pulse unit forms of the repetition frequency change or frequency hopping pulse signals include linear frequency modulation signals, non-linear frequency modulation signals, intra-pulse frequency coding signals, phase coding signals, rectangular pulse modulation signals, and ultra-wideband linear frequency modulation pulse signals.

[0199] 3. The measurement can be completed by using a widely common oscilloscope, without the need to develop a dedicated measurement device, which is simple and feasible, and has engineering practical value and popularization and application value.

[0200] 4. By calculating the power of the measured pulse signal or deriving the expression, the influence of the modulation characteristics of the radiation signal is solved; the oscilloscope and the antenna have fast response speeds, and the measurement is not affected by the response time.

[0201] Although the specific embodiments of the present invention have been described above, those skilled in the art should understand that this is only an example. The protection scope of the present invention is defined by the appended claims. Without departing from the principle and essence of the present invention, those skilled in the art can make various changes or modifications to these embodiments, but these changes and modifications all fall within the protection scope of the present invention.

Claims

1. A time-domain measurement method for the field strength of a pulse signal with variable pulse repetition frequency or frequency hopping, characterized in that: Step 1: Set the triggering mode of the time-domain measurement device to pulse-width triggering, measure the pulse signal with variable pulse repetition frequency or frequency hopping, and obtain time-domain parameters including pulse voltage amplitude. Step 2: Construct an analog periodic pulse signal according to the time-domain parameters of the pulse signal with variable pulse repetition frequency or frequency hopping. The time-domain parameters include modulation form, modulation parameters, pulse width, pulse repetition frequency, and carrier frequency. Step 3: Determine the field strength correction coefficient using the parameters of the analog periodic pulse signal. A: Pulse voltage amplitude of the analog periodic pulse signal. P: Power of the analog periodic pulse signal, which is peak power or average power. k os : The field strength correction factor of the PRF change or frequency hopping pulse signal, which is the peak field strength correction factor or the average field strength correction factor, corresponding to the peak power or average power of the simulated periodic pulse signal respectively; Step 4: Obtain the field strength of the radiation field of the pulse signal with variable pulse repetition frequency or frequency hopping according to the field strength correction coefficient and the measured reading of the pulse voltage amplitude.

2. The time-domain measurement method for the field strength of a repetitive frequency change or frequency hopping pulse signal radiation field according to claim 1, characterized in that, In Step 1, the range of the pulse-width triggering is less than twice the pulse width of the pulse signal with variable pulse repetition frequency or frequency hopping.

3. The time-domain measurement method for the field strength of a PRF-varying or frequency-hopping pulse signal radiation field according to claim 2, wherein , In Step 1, the range of the pulse-width triggering is 0.8 - 1.2 times the pulse width of the pulse signal with variable pulse repetition frequency or frequency hopping.

4. A time-domain measurement method for the field strength of a repetitive frequency change or frequency hopping pulse signal radiation field as claimed in claim 1, characterized in that In Step 1, for a frequency-hopping pulse signal, the time-domain parameters obtained including the pulse voltage amplitude further include the pulse repetition frequency.

5. A time-domain measurement method for the field strength of a repetitive frequency-varying or frequency-hopping pulse signal radiation field as claimed in claim 1, characterized in that, In Step 2, the modulation form of the analog periodic pulse signal is the same as that of the measured pulse signal with variable pulse repetition frequency or frequency hopping; the modulation parameters and pulse width are respectively equal to the modulation parameters and pulse width of the measured pulse signal with variable pulse repetition frequency or frequency hopping.

6. The time-domain measurement method for the field strength of a repetitive frequency change or frequency hopping pulse signal radiation field as described in claim 1, characterized in that, In Step 2, for a pulse signal with variable pulse repetition frequency, the carrier frequency of the analog periodic pulse signal is equal to the carrier frequency of the pulse signal with variable pulse repetition frequency; for a frequency-hopping pulse signal, the carrier frequency of the analog periodic pulse signal is any hopping carrier frequency of the frequency-hopping pulse signal.

7. A time-domain measurement method for the field strength of a repetitive frequency-varying or frequency-hopping pulse signal radiation field as described in claim 1, characterized in that, In Step 2, for a pulse signal with jittered pulse repetition frequency or sliding variable pulse repetition frequency, the pulse repetition frequency of the analog periodic pulse signal: f av = f even , f av : Pulse repetition frequency of the analog periodic pulse signal; f even : The center of the pulse repetition frequency range of the PRF jitter or PRF step change pulse signal.

8. The time-domain measurement method for the field strength of a repetitive frequency-varying or frequency-hopping pulse signal radiation field according to claim 1, characterized in that In Step 2, for a pulse signal with staggered pulse repetition frequency, the pulse repetition frequency of the analog periodic pulse signal, f av : Pulse repetition frequency of the analog periodic pulse signal; f m : The m-th pulse repetition frequency of the PRI staggering pulse signal; p m : Probability that the m-th pulse repetition frequency appears in the PRI staggering pulse signal; m: Natural number. N: Total number of pulse repetition frequencies of the pulse signal with staggered pulse repetition frequency.

9. The time-domain measurement method for the field strength of a PRF-varying or frequency-hopping pulse signal radiation field according to claim 1, characterized in that, In Step 2, for a frequency-hopping pulse signal, the pulse repetition frequency of the analog periodic pulse signal is equal to the pulse repetition frequency of the measured frequency-hopping pulse signal.

10. A time-domain measurement method for the field strength of a repetitive frequency change or frequency hopping pulse signal radiation field as described in claim 1, characterized in that, In Step 3, the power of the analog periodic pulse signal is achieved through theoretical derivation in the time domain or frequency domain using the parameters of the analog periodic pulse signal.

11. A time-domain measurement method for the field strength of a repetitive frequency change or frequency hopping pulse signal radiation field as described in claim 1, characterized in that, In Step 3, the field strength correction coefficient is determined using the simulation results. A sim : Given value of pulse voltage amplitude of simulated periodic pulse signal during simulation; P sim : The simulation result of the power of the analog periodic pulse signal, which is the simulation result of the peak power or the average power; k os The field strength correction factor of the PRF-varying or frequency-hopping pulse signal radiation field, which is the peak field strength correction factor or the average field strength correction factor, respectively corresponding to P sim corresponds to the peak power simulation result or the average power simulation result.

12. A time-domain measurement method for the field strength of a repetitive frequency change or frequency hopping pulse signal radiation field as described in claim 1, characterized in that, In step 3, for the radiation field of the PRF change or frequency hopping pulse signal where the pulse unit is a phase-coded pulse or a frequency-coded pulse, the peak field strength correction coefficient is 13. A time-domain measurement method for the field strength of a repetitive frequency-varying or frequency-hopping pulse signal radiation field as described in claim 1, characterized in that In Step 3, for the radiation field of a pulse signal with variable pulse repetition frequency or frequency hopping whose pulse unit is an ultra-wideband linearly frequency-modulated pulse, the peak field strength correction coefficient is where k os_p : peak field strength correction factor for the radiation field of the PRF-varying or frequency-hopping pulse signal; d: Time-bandwidth product, that is, the product of the signal occupancy bandwidth and the pulse width. z: Wideband index, which is the ratio of the carrier frequency to the signal occupancy bandwidth. S(·): Fresnel sine integral. C(·): Fresnel cosine integral.

14. A time-domain measurement method for the field strength of a repetitive frequency change or frequency hopping pulse signal radiation field as described in claim 13, characterized in that, In Step 3, for the radiation field of a pulse signal with variable pulse repetition frequency or frequency hopping whose pulse unit is an ultra-wideband linearly frequency-modulated pulse and the time-bandwidth product is 1, the peak field strength correction coefficient When z ∈ [0.554, 0.903], k os_p = 0.05cos(2π * 1.45 * z + 2.83) + 0.7; When z ∈ [1.089, 1.395], k os_p = 0.04cos(2π * 1.6 * z + 0.18) + 0.7; When z ∈ [1.538, 1.937], k os_p = -0.023cos(2π * 2.51 * z - 0.618) + 0.71; When z ∈ [2.05, 2.425], k os_p = 0.02cos(2π * 3z + 0.372) + 0.71; When z ∈ [2.54, 2.92], k os_p = -0.012cos(2π * 2.969 * z + 2.302) + 0.708; When z ∈ [3.035, 3.458], k os_p = -0.01cos(2π * 3.9 * z + 2.22) + 0.706; When z ∈ [3.598, 3.896], k os_p = 0.01 cos(2π * 4.8 * z + 1.8) + 0.707; When z is other values, 15. A time-domain measurement method for the field strength of a repetitive frequency change or frequency hopping pulse signal radiation field as described in claim 13, characterized in that, In Step 3, for the radiation field of a pulse signal with variable pulse repetition frequency or frequency hopping whose pulse unit is an ultra-wideband linearly frequency-modulated pulse and the time-bandwidth product is 2, the peak field strength correction coefficient, When z ∈ [0.516, 0.758], k os_p = -0.019cos(2π × 3.53 × z - 0.175) + 0.7; When z ∈ [0.767, 0.97], k os_p = 0.037cos(2π × 1.76 × z - 3.313) + 0.69; When z ∈ [1.026, 1.218], k os_p = 0.01 cos(2π × 5z - 0.66) + 0.7; When z ∈ [1.27, 1.498], k os_p = -0.011cos(2π × 3.96 × z + 1.312) + 0.71; When z ∈ [1.507, 1.715], k os_p = -0.012 cos(10π × z + 1.7) + 0.71; When \(z\in[1.777,1.962]\), \(k\) os_p \(=-0.011\cos(2\pi\times5.3\times z + 2.13)+0.71\); When z ∈ [2.03, 2.216], k os_p = 0.01 cos(2π × 5.7 × z - 2.11) + 0.71; When \(z\in[2.267,2.464]\), \(k\) os_p \( = 0.009\cos(2\pi\times6\times z - 2.23)+0.71\); When z ∈ [2.542, 2.714], k os_p = 0.009 cos(2π × 6.9 × z + 0.15) + 0.71; When z ∈ [2.767, 2.974], k os_p = 0.007cos(2π × 7.8 × z + 0.57) + 0.71; When z is other values, 16. A time-domain measurement method for the field strength of a repetitive frequency-varying or frequency-hopping pulse signal radiation field as described in claim 13, characterized in that, In step 3, for the radiation field of a PRF change or frequency hopping pulse signal where the pulse unit is an ultra-wideband linear frequency modulation pulse and the time-bandwidth product is greater than 2, the peak field strength correction factor is 17. A time-domain measurement method for the field strength of a repetitive frequency change or frequency hopping pulse signal radiation field according to claim 1, characterized in that In step 3, the quantitative relationship between the average field strength correction coefficient and the peak field strength correction coefficient: k os_a : Average field strength correction factor of the radiation field of the PRF change or frequency hopping pulse signal; k os_p : Peak field strength correction factor for repetitive frequency change or frequency hopping pulse signal radiation field; f av : Pulse repetition frequency of the analog periodic pulse signal; τ: Pulse width of the simulated periodic pulse signal.

18. A time-domain measurement method for the field strength of a repetitive frequency-varying or frequency-hopping pulse signal radiation field as described in claim 1, characterized in that, In step 4, the field strength of the radiation field of the PRF change or frequency-hopping pulse signal: Where: E p : Peak field strength of the radiation field of a PRF-varying or frequency-hopping pulse signal, unit: V / m; E a : Average field strength of the radiation field of a PRF-varying or frequency-hopping pulse signal, unit V / m; k os_a : Average field strength correction factor for the radiation field of a PRF-varying or frequency-hopping pulse signal; k os_p : Correction factor for peak field strength of repetitive frequency change or frequency hopping pulse signal radiation field k detector : Coefficient of the envelope detector, which is taken as 1 when the envelope detector is not used; A r is the measured reading of the pulse voltage amplitude, unit: V; F A : Antenna factor, unit dB / m; F D : Total attenuation of the attenuator and the connecting cable, unit dB.

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