A method for detecting high power microwave frequency under extremely short pulse

Abstract

The application discloses a high-power microwave frequency detection method under extremely short pulse, relates to the technical field of microwave measurement, and combines a signal generator, a horn antenna, a frequency converter and an oscilloscope to perform joint testing. The frequency of the signal generator is set. A wave source generated by the signal generator passes through a frequency multiplier of the frequency converter to generate a local oscillator signal of a target frequency. A to-be-detected radio frequency signal received by the horn antenna is input to a radio frequency input end of the frequency converter. The local oscillator signal and the to-be-detected radio frequency signal pass through a frequency mixer in the frequency converter to be mixed, pass through a band-pass filter to filter out an upper mixing component, and output an intermediate frequency signal to the oscilloscope. The frequency of the local oscillator signal of the signal generator is set twice, and the oscilloscope performs FFT transformation twice, so that true and false signals can be distinguished, the frequency of the to-be-detected radio frequency signal of the extremely short pulse high-power microwave is calculated, a special, efficient and reliable solution for the special and harsh measurement scene of the extremely short pulse high-power microwave is formed, and the instantaneous frequency spectrum of a microsecond pulse can be acquired through FFT transformation by means of extremely high time resolution and transient capture capability.

Description

Technical Field

[0001] This invention belongs to the field of microwave measurement technology, specifically a method for detecting high-power microwave frequencies under extremely short pulses. Background Technology

[0002] In cutting-edge technology fields such as radar, electronic warfare, high-power microwave weapons, and particle accelerators, accurately measuring the frequency of microsecond-level, high-power microwave pulse signals is a crucial and extremely challenging task.

[0003] Traditional spectrum analyzers, due to their wide bandwidth and high sensitivity, have long been the standard tool for frequency measurement. Testing microsecond-level pulse signals requires test equipment with high time resolution and power tolerance. Traditional spectrum analyzer sweep testing methods, when testing microsecond-level signals, are prone to signal omissions due to insufficient scanning speed, leading to decreased frequency measurement accuracy. They also have weak capabilities for analyzing the time-domain details and instantaneous broadband spectrum of short pulses. Furthermore, when applied to microsecond-level high-power pulse scenarios, they reveal several key shortcomings that make them unsuitable for meeting testing requirements: 1. Insufficient temporal resolution and scanning speed bottleneck: Traditional spectrum analyzers primarily operate based on a frequency sweep mechanism, requiring their local oscillator to scan within a certain frequency range. This process is time-consuming, often exceeding microseconds. This inherently "slow" scanning characteristic prevents them from capturing and responding to transient short pulse signals, resulting in severe spectral leakage and reduced frequency resolution, and an inability to accurately reflect the instantaneous spectral characteristics during the pulse's duration.

[0004] 2. Extremely low power tolerance and risk of signal distortion: Commercial spectrum analyzers typically have strict power limitations at their input ports (usually < 30dBm / 1W), while the peak power of high-power microwave pulses can reach kilowatts or even megawatts. To perform measurements, the signal must be significantly attenuated. This process not only reduces the signal amplitude but can also introduce nonlinear distortion and alter the pulse waveform, causing the measured spectrum to deviate from the true spectrum of the original signal, thus compromising measurement accuracy.

[0005] 3. Limitations of system dead time and FFT processing capability: Traditional spectrum analyzers face significant challenges in accurately analyzing the spectral characteristics of microsecond-level high-power pulse signals due to limitations in dead time and FFT window length, especially in applications requiring simultaneous time resolution and power tolerance.

[0006] Therefore, a significant technological gap exists between accurate frequency measurement and the capabilities of traditional measurement tools, highlighting the urgency and necessity of developing novel detection methods. Consequently, providing a novel detection method capable of accurately measuring the frequency of high-power microwave pulses at the microsecond level without reducing the input signal power has become a key problem urgently needing to be solved in this technological field. Summary of the Invention

[0007] The present invention aims to solve at least one of the technical problems existing in the prior art; to this end, the present invention proposes a method for high-power microwave frequency detection under extremely short pulses.

[0008] A method for detecting high-power microwave frequencies under extremely short pulses includes the following steps: The frequency of the signal generator is set, and the wave source generated by the signal generator is used to generate the local oscillator signal of the target frequency through the frequency multiplier of the frequency converter. The radio frequency signal to be tested received by the horn antenna is input to the radio frequency input terminal of the frequency converter. The local oscillator signal and the radio frequency signal under test are mixed by the mixer in the inverter, and the overmixing component is filtered out by the bandpass filter, and the intermediate frequency signal is output to the oscilloscope. The oscilloscope performs an FFT transform on the intermediate frequency signal and outputs the spectrum of the first intermediate frequency signal; Change the frequency of the signal generator and repeat the above steps to obtain the spectrum of the second intermediate frequency signal; The oscilloscope outputs the intermediate frequency signal spectrum through two FFT transformations, obtains the absolute value of the difference between the frequency of the RF signal under test and the local oscillator signal, eliminates false signals, and obtains the frequency value of the RF signal under test.

[0009] Furthermore, the inverter integrates a frequency multiplier, a mixer, and a bandpass filter connected in sequence.

[0010] Furthermore, the frequency multiplier is used to multiply the local oscillator signal output from the signal generator to the target frequency band; the mixer is used to down-convert the RF input signal and the local oscillator signal; the bandwidth and frequency of the bandpass filter are matched with the intermediate frequency signal to suppress the upper sideband mixing signal and output the down-mixed signal. The mixer down-converts the high-power GHz RF signal into a low-power MHz intermediate frequency signal, which is then sent to the oscilloscope to achieve non-destructive measurement of the high-power signal.

[0011] Furthermore, the frequency converter provides at least two local oscillator signal input ports, each corresponding to a different multiplication factor to accommodate radio frequency signals under test in different frequency bands. The frequency converter has two local oscillator signal input ports: a low local oscillator input port of 4.58–7.08 GHz (24x multiplication) and a high local oscillator input port of 9.16–14.16 GHz (12x multiplication). The frequency converter's receiving frequency range is 110–170 GHz, and its output intermediate frequency bandwidth is 5 MHz–40 GHz.

[0012] Furthermore, the frequency range of the inverter is 110 to 170 GHz, and the local oscillator signal input port includes a port that supports 4.58 to 7.08 GHz input and is multiplied by 24, and a port that supports 9.16 to 14.16 GHz input and is multiplied by 12.

[0013] Furthermore, the oscilloscope has a bandwidth of 1 GHz, and the intermediate frequency signal frequency f output by the mixer is... IF The frequency range is 5MHz to 40GHz. The difference between the local oscillator frequency output by the signal generator and the frequency of the radio frequency signal under test is multiplied and mixed to generate an intermediate frequency signal frequency that must fall within the effective analysis bandwidth of the oscilloscope. The local oscillator frequency set twice is not equal, and the local oscillator frequency set should differ from the frequency of the radio frequency signal under test by 5MHz to 1GHz so that the oscilloscope can accurately capture the intermediate frequency signal information.

[0014] Furthermore, the sampling rate of the oscilloscope satisfies the Nyquist sampling theorem.

[0015] Furthermore, the oscilloscope has a maximum sampling rate fs of 10GS / s and a minimum sampling interval of [missing value], enabling it to accurately measure signal changes at the 100 picosecond level, making it suitable for short pulse signal measurement.

[0016] Furthermore, when performing FFT analysis on an oscilloscope, the zoom range is adjusted to eliminate interference from rising edges, falling edges, and pulse intervals. High temporal resolution allows the zoom function to focus on any specific period of the pulse for analysis, thereby revealing these subtle transient spectral characteristics.

[0017] Furthermore, the relationship between the signal segment length ΔT selected by Zoom and the frequency resolution Δf is Δf = 1 / ΔT. By increasing the Zoom segment length ΔT, the FFT resolution Δf = 1 / ΔT is improved, thereby reducing the frequency resolution error.

[0018] Compared with the prior art, the beneficial effects of the present invention are: This invention uses an oscilloscope to accurately capture the rising edge, pulse width, and other time-domain characteristics of microsecond-level pulses; the oscilloscope can acquire the instantaneous spectrum of the entire frequency band through a single FFT, avoiding the omission of most transient signals for non-repetitive pulses or frequency-hopping signals; by down-converting the frequency using a mixer, GHz-level high-power signals can be reduced to the safe range of the oscilloscope; through the test system and signal processing flow, accurate frequency measurement of high-power, short-pulse-width microwave signals is achieved. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the high-power microwave frequency detection system under extremely short pulses according to the present invention; Figure 2 This is a spectrum diagram of the intermediate frequency signal obtained by testing the local oscillator signal 1 according to the present invention; Figure 3 The intermediate frequency signal spectrum information obtained by testing the local oscillator signal 2 of this invention is shown in the figure. Detailed Implementation

[0020] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Example 1: This application provides a method for detecting high-power microwave frequencies under extremely short pulses, including the following steps: First test: Set the frequency of the signal generator. The wave source generated by the signal generator is multiplied by the frequency multiplier of the frequency converter to generate the local oscillator signal of the target frequency. The radio frequency signal to be tested received by the horn antenna is input to the radio frequency input terminal of the frequency converter. The local oscillator signal and the radio frequency signal under test are mixed by the mixer in the inverter, and the overmixing component is filtered out by the bandpass filter, and the intermediate frequency signal is output to the oscilloscope. The oscilloscope performs an FFT transformation on the intermediate frequency signal and outputs the spectrum of the first intermediate frequency signal and the first intermediate frequency frequency corresponding to its peak value. Second test: Change the frequency of the signal generator and repeat the above steps to obtain the spectrum of the second intermediate frequency signal and the second intermediate frequency corresponding to its peak value; The frequency of the RF signal under test is calculated through two FFT transformations. The oscilloscope outputs the intermediate frequency signal spectrum through two FFT transformations, and the absolute value of the difference between the frequency of the RF signal under test and the local oscillator frequency is obtained to eliminate false signals and obtain the frequency value of the RF signal under test. Based on the first setting of the local oscillator frequency, the second setting of the local oscillator frequency, the first intermediate frequency, and the second intermediate frequency, the true and false frequencies are distinguished by calculation, thereby obtaining the accurate frequency of the RF signal under test.

[0022] By constructing a test system consisting of a signal generator, a horn antenna, a frequency converter (including a frequency multiplier, a mixer, and a bandpass filter), and an oscilloscope, the signal generator produces a wave source, which is input to the local oscillator signal input terminal of the frequency converter; the frequency multiplier generates a local oscillator signal at the target frequency; the horn antenna receives the radio frequency signal under test and inputs it to the radio frequency input terminal of the frequency converter; the local oscillator signal and the radio frequency signal under test pass through the mixer and bandpass filter inside the frequency converter and output a down-converted signal from the intermediate frequency output terminal to the oscilloscope; the oscilloscope obtains the intermediate frequency signal spectrum by performing an FFT transformation, which can also obtain the absolute value of the difference between the frequency of the radio frequency signal under test and the frequency of the local oscillator signal. By setting the local oscillator signal frequency a second time, the oscilloscope outputs the intermediate frequency signal spectrum after two FFT transformations, which can eliminate false signals and obtain the accurate frequency value of the RF signal under test. The oscilloscope can accurately capture the rising edge, pulse width and other time-domain characteristics of microsecond-level pulses. The oscilloscope can obtain the instantaneous spectrum of the entire frequency band through a single FFT, and avoid missing most transient signals for non-repetitive pulses or frequency-hopping signals. By down-converting the frequency through a mixer, GHz-level high-power signals can be reduced to the safe range of the oscilloscope.

[0023] Example 2: As an embodiment of this application, it specifically includes the following methods: Construct a microwave frequency detection system based on a signal generator, horn antenna, frequency converter, and oscilloscope; Connect the output of the signal generator to the local oscillator signal input of the frequency converter. After processing by the frequency multiplier circuit inside the frequency converter, the required local oscillator frequency is generated. At the same time, the horn antenna that receives the frequency signal to be tested is connected to the radio frequency input terminal of the frequency converter; The inverter mixes the received radio frequency input signal with the local oscillator signal, and filters out the overmixing component through a filter circuit, finally outputting the intermediate frequency signal to the oscilloscope. Oscilloscopes use Fast Fourier Transform (FFT) to perform spectrum analysis on intermediate frequency (IF) signals, thereby outputting the spectral characteristics of the IF signals. Then, set the local oscillator signal frequency again and repeat the above operation. Perform two FFT transformations on the oscilloscope to distinguish between true and false signals and obtain the frequency of the RF signal under test.

[0024] By setting different local oscillator frequencies twice and taking measurements, a set of equations can be constructed. By calculating and eliminating interference from "false signals" such as image frequencies, the accuracy of the final frequency result can be ensured.

[0025] The test procedure is shown in Table 1: Table 1 Test Flowchart As an embodiment of the present invention, a preferred formula for calculating the frequency of the short-pulse high-power microwave radio frequency signal under test is as follows: Let the local oscillator signal generated by the signal generator be: (1) in, For the local oscillator amplitude, This is the local oscillator frequency.

[0026] The frequency multiplier in the inverter increases the local oscillator frequency by a factor of M, and the output signal is: (2) Assume the short-pulse radio frequency signal received by the external horn antenna on the frequency converter is an ideal square wave: (3) Among them, A RF The amplitude of the signal pulse. The center time of the pulse. Let t be the pulse width, and rect(t) be the rectangular function. (4) Let be the frequency to be measured (RF). Therefore, the output signal of the multiplier mixer is: (5) Once unfolded, you will get: (6) This includes sum and difference frequency components. Since the filter's transition band and ripple have almost no impact on the theoretical derivation of this invention, the bandpass filter can be assumed to be an ideal filter, and its frequency response function can be expressed as: (7) Where f0 is the center frequency and B is the filter bandwidth. When the difference frequency... satisfy At that time, the intermediate frequency signal can be output after filtering: (8) The intermediate frequency signal is output to an oscilloscope, and the time-domain signal is sampled by the oscilloscope's internal analog-to-digital converter (ADC). Let the sampling rate be f. s (Number of sampling points per second), according to the Nyquist criterion: Otherwise, spectral aliasing will occur. Sampling interval Let the discrete sampling point index be n (n=0,1,2,...,N-1), where N is the total number of sampling points, and the corresponding time is... Then the continuous signal s IF (t) After sampling, the discrete sequence s is obtained. IF[n] is: (9) To extract target signal features, suppress irrelevant noise, and balance resolution and computational resources, the oscilloscope is configured to truncate the signal in the time domain (selecting a zoom period). Let the selected zoom duration be... (where m is the number of points), generate a new sequence: (10) Where Rect is a rectangular window function, defining the start and end times of the Zoom segment. This ensures that the Zoom segment begins within the pulse width range.

[0027] To suppress spectral leakage, windowing is applied to the zoom band. The oscilloscope's default window function is the Hanning window. (11) Signals after windowing: (12) After unfolding, we get: (13) For s w [n] Perform an m-point FFT: (14) The final power spectrum of the intermediate frequency signal is output by the oscilloscope: (15) Where ENBW is the equivalent noise bandwidth of the Hanning window. IF : (16) Spectral resolution (f) s ’ The effective sampling rate of the Zoom segment. (This refers to the total duration of the zoom segment). Therefore, the radio frequency to be measured can be deduced from the intermediate frequency signal frequency. (17) At this point, the exact frequency value of the RF signal under test still cannot be obtained, and a second measurement is required. The local oscillator signal frequency is then input into the signal generator. ,and By continuing the above calculations and derivations, the intermediate frequency can be obtained. Therefore, the frequency of the radio frequency signal under test can also be deduced again: (18) After two tests and calculations, by comparing equation (17) with equation (18), the true and false signals can be distinguished, and the unique frequency of the radio frequency signal to be tested can be obtained.

[0028] like Figure 1 As shown, a microwave frequency detection system based on a signal generator, horn antenna, frequency converter, and oscilloscope is constructed. The frequency converter integrates a frequency multiplier, a mixer, and a bandpass filter connected in sequence. This method has wide applicability, is not affected by frequency band, and the measurement range is determined by the signal source and frequency multiplier according to requirements.

[0029] As an embodiment of the present invention, preferably, the frequency multiplier is used to multiply the local oscillator signal output by the signal generator to the target frequency band; the mixer is used to down-convert the RF input signal and the local oscillator signal; the bandwidth and frequency of the bandpass filter are matched with the intermediate frequency signal to suppress the upper sideband mixing signal and output the down-mixed signal. The down-conversion process is linear, which can preserve the spectral information of the original RF signal and avoid nonlinear distortion that may be caused by strong attenuation, thereby ensuring the authenticity of the measurement results.

[0030] As an embodiment of the present invention, preferably, the oscilloscope has a bandwidth of 1 GHz, and the intermediate frequency signal frequency f output by the mixer is... IF The local oscillator frequency is between 5MHz and 1GHz, and the two local oscillator frequency settings are not equal, with the difference between the local oscillator frequency and the frequency of the radio frequency signal under test being within the range of 5MHz to 1GHz.

[0031] As an embodiment of the present invention, preferably, the sampling rate of the oscilloscope satisfies the Nyquist sampling theorem, that is, it satisfies... To prevent spectral aliasing.

[0032] As an embodiment of the present invention, preferably, the oscilloscope has a maximum sampling rate fs of 10GS / s and a minimum sampling interval of , which can accurately measure signal changes at the level of 100 picoseconds, and is suitable for the short pulse signal measurement described in the present invention.

[0033] As an embodiment of the present invention, preferably, the frequency converter provides at least two local oscillator signal input ports, each corresponding to a different multiplication factor to accommodate radio frequency signals under test in different frequency bands. The frequency converter has two local oscillator signal input ports: a low local oscillator input port of 4.58–7.08 GHz (24x multiplication) and a high local oscillator input port of 9.16–14.16 GHz (12x multiplication); the frequency converter's receiving frequency range is 110–170 GHz, and its output intermediate frequency bandwidth is 5 MHz–40 GHz.

[0034] As an embodiment of the present invention, preferably, the receiving frequency range of the frequency converter is 110 to 170 GHz, and the local oscillator signal input port includes a port that supports 4.58 to 7.08 GHz input and is multiplied by 24, and a port that supports 9.16 to 14.16 GHz input and is multiplied by 12.

[0035] As one embodiment of the present invention, preferably, the radio frequency pulse signal is an ideal square wave. However, in actual testing, the signal pulse may have rising and falling edges, modulation jumps, or abnormal oscillations. Therefore, the zoom range can be adjusted to eliminate interference from irrelevant time periods. When performing FFT analysis on an oscilloscope, the zoom range is adjusted to eliminate interference from rising edges, falling edges, and pulse intervals.

[0036] As an embodiment of the present invention, preferably, the relationship between the signal segment length ΔT selected by Zoom and the frequency resolution Δf is Δf = 1 / ΔT. By increasing the Zoom segment length ΔT, the FFT resolution Δf = 1 / ΔT is improved, and the frequency resolution error is reduced.

[0037] Example 3: As an embodiment of the present invention, the theoretical formula for calculating the frequency of the short-pulse high-power microwave radio frequency signal under test is preferably derived as follows: Let the local oscillator signal generated by the signal generator be: Among them, A LO f is the amplitude of the local oscillator. LO This is the local oscillator frequency.

[0038] The frequency multiplier in the inverter increases the local oscillator frequency by a factor of M, and the output signal is: Assume the short-pulse radio frequency signal received by the external horn antenna on the frequency converter is an ideal square envelope carrier: Among them, A RF Let t0 be the amplitude of the signal pulse and t0 be the center time of the pulse. Let t be the pulse width, and rect(t) be the rectangular function. f RF Let be the frequency to be measured (RF). Therefore, the output signal of the multiplier mixer is: Once unfolded, you will get: This includes sum and difference frequency components. Since the transition band and ripple of the filter have almost no impact on the theoretical derivation of this invention, it can be assumed that the bandpass filter is an ideal filter, and its frequency response function can be expressed as: Where f0 is the center frequency and B is the filter bandwidth. When the difference frequency... satisfy At that time, the intermediate frequency signal can be output after filtering: The intermediate frequency signal is output to an oscilloscope, and the time-domain signal is sampled by the oscilloscope's internal analog-to-digital converter (ADC). Let the sampling rate be fs (samples per second). According to the Nyquist criterion: Otherwise, spectral aliasing will occur. Sampling interval Let the discrete sampling point index be n (n=0,1,2,...,N-1), where N is the total number of sampling points, and the corresponding time be t=nT. s Then the continuous signal S IF (t) After sampling, the discrete sequence S is obtained. IF [n] is: To extract target signal features, suppress irrelevant noise, and balance resolution and computational resources, an oscilloscope is used to truncate the signal in the time domain, selecting a zoom period. Let the selected zoom duration be ΔT = mT. s Let m be the number of points, and generate a new sequence: Where Rect is a rectangular window function, defining the start and end times of the Zoom segment. This ensures that the Zoom segment begins within the pulse width range.

[0039] To suppress spectral leakage, windowing is applied to the zoom band. The oscilloscope's default window function is the Hanning window. Signals after windowing: After unfolding, we get: Perform an m-point FFT on sw[n]: The final power spectrum is output by the oscilloscope: Where ENBW is the equivalent noise bandwidth of the Hanning window. IF : Spectral resolution (fs' is the effective sampling rate of the Zoom segment, (This refers to the total duration of the zoom segment). Therefore, the radio frequency to be measured can be deduced from the intermediate frequency signal frequency. The local oscillator frequency set by the signal generator is f LO= The frequency converter used is a Nostradamus C06DAS01, operating at 14.2 GHz. The local oscillator signal is input to the high-frequency input of the converter and multiplied by 12 to obtain 169.8 GHz. The intermediate frequency signal spectrum output by the oscilloscope is as follows: Figure 2 As shown, the frequency corresponding to the spectral peak is f. IF =0.23GHz, therefore it can be calculated that 170.63GHz / 170.17GHz.

[0040] At this point, a second measurement is performed, with the local oscillator signal frequency input to the signal generator. ,and Using the same calculations and derivations as above, we can obtain the intermediate frequency. Therefore, the frequency of the radio frequency signal under test can also be deduced again: The second setting of the local oscillator signal frequency f LO ， =14.15GHz, the intermediate frequency signal spectrum is obtained as follows Figure 3 As shown, the frequency corresponding to the spectral peak is f. IF ， =0.17GHz, therefore it can be calculated that 169.97GHz / 169.63GHz. After two tests and calculations, the two sets of frequencies of the RF signal under test were compared to obtain an approximate value of the frequency of the RF signal under test. The initial target signal frequency was set at 170GHz. There is only about 0.1% error between 169.97GHz and 170.17GHz.

[0041] The above embodiments are only used to illustrate the technical methods of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical methods of the present invention without departing from the spirit and scope of the technical methods of the present invention.

Claims

1. A method for detecting high-power microwave frequencies under extremely short pulses, characterized in that, Includes the following steps: The frequency of the signal generator is set, and the wave source generated by the signal generator is used to generate the local oscillator signal of the target frequency through the frequency multiplier of the frequency converter. The radio frequency signal to be tested received by the horn antenna is input to the radio frequency input terminal of the frequency converter. The local oscillator signal and the radio frequency signal under test are mixed by the mixer in the inverter, and the overmixing component is filtered out by the bandpass filter, and the intermediate frequency signal is output to the oscilloscope. The oscilloscope performs an FFT transform on the intermediate frequency signal and outputs the spectrum of the first intermediate frequency signal; Change the frequency of the signal generator and repeat the above steps to obtain the spectrum of the second intermediate frequency signal; The frequency value of the radio frequency signal under test is calculated by two FFT transformations.

2. The method for detecting high-power microwave frequencies under extremely short pulses according to claim 1, characterized in that, The inverter integrates a frequency multiplier, a mixer, and a bandpass filter connected in sequence.

3. The method for detecting high-power microwave frequencies under extremely short pulses according to claim 2, characterized in that, A frequency multiplier is used to multiply the local oscillator signal output by the signal generator to the target frequency band; a mixer is used to downconvert the RF input signal and the local oscillator signal; and the bandwidth and frequency of the bandpass filter are matched with the intermediate frequency signal.

4. The method for detecting high-power microwave frequencies under extremely short pulses according to claim 1, characterized in that, The oscilloscope has a bandwidth of 1 GHz, and the intermediate frequency signal frequency f output by the mixer is... IF The frequency range is 5MHz to 40GHz. The difference between the local oscillator frequency output by the signal generator and the frequency of the radio frequency signal under test is multiplied and mixed to generate an intermediate frequency signal that must fall within the effective analysis bandwidth of the oscilloscope.

5. The method for detecting high-power microwave frequencies under extremely short pulses according to claim 1, characterized in that, The sampling rate of the oscilloscope satisfies the Nyquist sampling theorem.

6. The method for detecting high-power microwave frequencies under extremely short pulses according to claim 5, characterized in that, oscilloscope sampling rate f s The maximum sampling rate is 10 GS / s, and the minimum sampling interval is 100 ps.

7. The method for detecting high-power microwave frequencies under extremely short pulses according to claim 1, characterized in that, The frequency converter provides at least two local oscillator signal input ports, each corresponding to a different multiplication factor, to accommodate radio frequency signals under test in different frequency bands.

8. The method for detecting high-power microwave frequencies under extremely short pulses according to claim 1, characterized in that, The frequency range of the inverter is 110 to 170 GHz. The local oscillator signal input ports include one port that supports 4.58 to 7.08 GHz input and is multiplied by 24, and another port that supports 9.16 to 14.16 GHz input and is multiplied by 12.

9. The method for detecting high-power microwave frequencies under extremely short pulses according to claim 1, characterized in that, When performing FFT analysis on an oscilloscope, the zoom range can be adjusted to eliminate interference from rising edges, falling edges, and pulse intervals.

10. The method for detecting high-power microwave frequencies under extremely short pulses according to claim 9, characterized in that, The relationship between the signal segment length ΔT selected by Zoom and the frequency resolution Δf is Δf = 1 / ΔT. By increasing the length, the FFT resolution is improved and the frequency resolution error is reduced.

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