CN115510786A - Frequency calculation method and system for high dynamic impact signal - Google Patents

Abstract

The invention provides a frequency calculation method and a frequency calculation system for a high dynamic impact signal. The system comprises a frequency mixing module, a signal acquisition module and a frequency resolving module. The circuit parameters of the frequency mixing module, such as the number of channels, a filter, a local oscillator signal and the like, are determined by simulation optimization; when in measurement, signals enter a plurality of channels simultaneously after being input into a frequency mixing module, each channel has different signal frequency bands, and the signals of the channels are converted into difference frequency signals of a low frequency band; the difference frequency signal is input into a signal acquisition module after being filtered, and measurement data of different signal frequency bands are obtained; and the frequency calculating module is used for solving the instantaneous frequency of the signal according to the frequency spectrum parameters and the measurement data of multiple channels, so that the impact speed is obtained. The invention has the characteristics that the requirements on the sampling rate and the circuit manufacture are reduced by utilizing multi-channel mixing, the frequency calculation of high dynamic signals can be realized, and the invention has important application prospect in the field of high dynamic impact signal measurement.

Description

Frequency calculation method and system for high dynamic impact signal

Technical Field

The invention relates to a frequency resolving method and a frequency resolving system for high dynamic impact signals, which are used for resolving the frequency of the high dynamic impact signals generated by a laser interferometry and belong to the field of high dynamic signal measurement.

Background

With the trend of informatization, digitization and intellectualization in the military field, various penetration weapons are well developed, in the process of weapon equipment development, strong impact environment experiment verification needs to be carried out on an intelligent sensing system, a missile-borne instrument and the like carried by the weapon equipment, so that the measurement of various parameters of a projectile body is more important, and the emergent and flying states of the projectile body can be analyzed in detail by acquiring the speed of the projectile when the projectile is taken out of a chamber, flies, hits a target and the like. Instantaneous velocities of magnitude up to or exceeding 200m/s may be encountered in experiments, and for such velocity measurements, a number of methods are available, most typically time interval measurements, but the average velocity obtained is of limited information and cannot be used to study the entire ballistic motion process. Currently, the measurement speed can be divided into two categories according to the measurement mode: contact and contactless. The contact type measurement mainly refers to on-off target, which is a target signal generated by using a mode of opening or closing a circuit in the device to generate a pulse electric signal when a projectile passes through the target surface, and the pulse electric signal is used as a target signal for opening or closing a timer to time. The contact type measuring method has the advantages of simple structure, convenience in manufacturing, strong anti-interference capability and the like, so that the contact type measuring method is widely applied to early projectile velocity measurement. But at the same time this method is accompanied by its own inherent drawback, namely the impact on the trajectory of the flight. In contrast, non-contact measurement has been widely used due to its advantages such as almost no impact on trajectory and non-destructive testing.

The transient high-speed laser speed measurement technology based on the laser interferometry has the advantages of high measurement precision, wide speed measurement range, fast dynamic response and the like. In the impact measurement process, a laser Doppler principle is adopted, and a diffraction grating is used as a cooperative target, so that Doppler frequency shift generated by grating movement has correlation with impact speed. In a grating Laser Doppler Velocimeter technique for measuring The lateral velocity of an object (The Technology of a grating Laser Doppler Velocimeter for measuring The velocity of a transition of objects), which is a paper made by Zhang et al in International Symposium on Optoelectronic Technology and Application 9297 (International Symposium on Optoelectronic Technology and Application), 2014, a grating Doppler detection system is designed, a differential measurement method is adopted for measurement, and after two diffracted lights of a grating are mixed, a detector detects The beat frequency when The grating moves. In the 'method for measuring the moving speed of an object based on the Doppler effect of a polarization grating' (patent number: 202011457850.6) applied for Chinese patents such as Ren Yuan in 2020, a method for obtaining linearly polarized light with beat frequency characteristics by superposing +/-1-order diffracted lights of the polarization grating is provided, and time-frequency analysis is performed on signals by adopting short-time Fourier transform, so that the characteristic that the moving speed changes along with time is obtained. Therefore, it is necessary to obtain the doppler shift signal accurately and rapidly in real time. High dynamic impact signals have many of its unique features: the whole impact process is very short, the time is in millisecond order, the signal is dynamically changed, the dynamic range of the frequency is large, and the bandwidth is narrow at a certain moment. For the signal to be measured, the signal frequency may be as high as several hundred mhz, a very high sampling rate is required during acquisition, and a very large data volume exists during transmission and processing, which causes great difficulty in sampling and processing the signal in real time.

In recent years, related technologies have been described at home and abroad for a measuring device and a method for high dynamic impact signals. In 2015, a new method for verifying or calibrating impact velocity by using an impact velocity measuring device (patent number: 201510915520. X) is provided by applying Chinese patents such as Wang Jiang of the national institute of metrology and science of Anhui province, and the like, wherein the impact velocity measuring device comprises a signal receiving antenna, a frequency spectrum processing module and a signal processing module, and a high-gain receiving antenna and a pulse width capturing mode and a pulse width capturing module with dominant frequency up to 150MHz are adopted for acquisition, so that high-precision velocity measurement is realized. In 2021, wu congestion and other applications for the chinese patent "rock burst data acquisition substation and acquisition method" (patent No. 202111403425.3) proposed a method for reducing data storage capacity by storing data according to signal intensity and acquisition frequencies of a first frequency and a second frequency, respectively. In 2019, china patents such as Heilongjiang university Lv Guohui and the like, which apply for high-speed high-frequency shock wave overpressure data acquisition device and acquisition method (patent number: 201910065953.9), provide a data acquisition device comprising a signal acquisition module, an optical trigger module, a remote transmission module, a data storage module and a control module. A high-speed high-frequency shock wave overpressure data acquisition device and an acquisition method are provided in Chinese patent application No. 201920833433.3 such as Xu Cheng in 2019, and are triggered by optical signals, so that data acquisition, remote transmission, storage and the like can be realized. The development of impulse signal sampling technology is promoted to a great extent by the method, however, due to the high-frequency characteristic of the impulse signal, the requirements of real-time sampling and data transmission on an acquisition system are higher.

The high dynamic impact signal has the characteristic of high frequency, so that the sampling rate of data acquisition is higher, and various measurement modes are available for signals with the characteristics. In 2014, damilla et al proposed to compensate amplifiers by using compressive sensing technology in a paper "Compressed sensing technology based on nonlinear post-compensation of receivers in OFDM system" in Signal processing "volume 97, page 282 (Compressed sensing technologies for receiver based on-position-compensation of transmitter's nonlinear detectors in OFDM systems). Yamamoto et al, 2021, in the article "Metal Ratio isochronous Sampling" of the 27th International institute of IEEE On-Line Testing and Robust System Design (IOLTS) ", an Efficient Waveform Acquisition Method (Metallic Ratio Acquisition-Time Sampling: AHighly efficiency Waveform Acquisition Method) proposed to set the signal frequency and Sampling frequency of an input signal to a metal Ratio when Waveform Acquisition is performed using Equivalent Sampling. Chinese patents such as Li Mei of Anhui university of Engineers in 2012 apply for a partial discharge signal acquisition device based on a frequency mixing technology (patent number: 201220049848. X), so that a partial discharge ultrahigh frequency signal is subjected to frequency reduction by applying the frequency mixing technology, and characteristics such as a peak value and a phase of the signal are reserved, so that a core problem in partial discharge ultrahigh frequency detection of a transformer is solved. The patent application of China, such as Liu Lianxi of the university of Western-style electronic technology in 2017, namely variable gain mixer amplifier, biological signal acquisition and processing chip and system (patent number: 201710375510.0) adopts the variable gain mixer amplifier to receive biological signals and local oscillator signals and output modulated audio signals. The methods effectively reduce the frequency of the high-frequency signals, thereby weakening the difficulty of sampling and data transmission of the signals. However, when sampling and solving the high dynamic impact signal, methods for frequency reduction processing and sampling of the signal and storing, transmitting and solving the measurement data are still lacking.

Based on the above background, the invention provides a frequency calculation method and system for a high dynamic impact signal, which are used for solving the problems of acquisition and processing of the high dynamic impact signal with constantly and dynamically changing frequency. The method mainly comprises three steps, wherein in the first step, a circuit design scheme of the acquisition system is determined according to the frequency range of a signal to be detected, the signal to be detected enters a plurality of channels and is mixed with different local oscillator signals, so that the frequency reduction of a dynamic conversion signal is realized, and therefore, the optimal number of the channels can be selected in a simulation mode firstly, so that the effective reduction of the signal frequency and the control of the circuit cost and the data acquisition processing difficulty are ensured. And secondly, filtering Doppler frequency shift signals generated by projectile impact in different frequency ranges, enabling the Doppler frequency shift signals to enter a plurality of actual acquisition channels, mixing the Doppler frequency shift signals with local oscillation signals of each channel to obtain low-frequency difference frequency signals, converting the mixed signals into digital signals by an analog-to-digital conversion chip after the mixed signals are subjected to filtering, amplification and the like, and transmitting the digital signals to the FPGA for storage and transmission. And thirdly, restoring and processing the acquired signals, compensating the signals according to the simulation result, screening and combining the acquired data of a plurality of channels, restoring the acquired whole impact process, obtaining the signal frequency by using Hilbert-Huang transform, and calculating the impact speed of the projectile according to the Doppler frequency shift correlation principle.

The method is characterized in that according to the characteristics of a signal to be detected, firstly, the acquisition quality of the signal under different conditions is simulated by using a simulation mode, and the circuit cost and the data storage and transmission difficulty are comprehensively considered, so that an optimal acquisition scheme is determined, wherein the optimal acquisition scheme comprises circuit parameters such as the number of channels, filter parameters, the frequency of a local oscillation signal and the like; before collection, multi-channel frequency mixing is carried out on the high dynamic impact signals, and the frequency of the signals to be detected is reduced so as to solve the problem that the high frequency signals are difficult to sample and transmit. The invention has the advantages that the frequency mixing processing is carried out on the electric signals to reduce the sampling rate of the signals, thereby not only effectively reducing the data quantity needing to be stored and transmitted, but also reducing the requirements on the design part of an analog circuit; due to the dynamic characteristic of rapid change of the impact signal, the multi-channel parallel circuit can sample simultaneously, so that the problem that a single channel cannot be captured due to short time of the impact signal is avoided; corresponding channel numbers and local oscillation signals can be designed according to signals with different range frequencies, and the application range of the method is expanded.

In summary, according to the frequency calculation method and system for the high dynamic impact signal provided by the invention, on the basis of traditional signal sampling, multichannel frequency mixing processing is added to the analog circuit part, so that the signal frequency is reduced, the impact signal can be captured in real time, and the subsequent requirements on signal acquisition and the data volume needing to be stored and transmitted are effectively reduced; and aiming at impact signals with different characteristics, the optimal design scheme of the frequency reduction circuit part can be determined through simulation, the number of channels and the frequency of the local oscillator signal are adjusted, and the method has good applicability to frequency calculation and processing of high dynamic impact signals.

Disclosure of Invention

Technical problem to be solved

The invention aims to provide a frequency calculation method and a frequency calculation system for high-dynamic impact signals, which are used for solving the problem of acquisition of rapidly-changing high-frequency dynamic signals.

(II) technical scheme

The invention discloses a frequency calculation method and a frequency calculation system for a high dynamic impact signal, which comprise the following steps:

step one, determining the optimal design scheme of the frequency reducing circuit part through simulation according to the frequency range, the change speed and the like of the signal to be detected under different conditions. The signal to be measured is simulated,

wherein the amplitude A of the signal _t Frequency omega _t And phase

The frequency range is ω with time t, respectively ₀ ＜ω _t ≤ω _max ，

M＝ω _max -ω ₀ (2)

That is, M is the frequency bandwidth of the whole process of the signal, if the frequency bandwidth of the signal that can pass through each channel in the frequency reduction process is M, the number of channels n is selected to be larger than M

The smallest integer, the passable frequency of each channel is,

in order to avoid missing acquisition of boundary frequency signals, there is an overlapping portion of the signal frequency ranges that two adjacent channels can pass through. In order to simulate various experimental environments and ensure the accuracy of results, random noises with different sizes are added on the basis of original signals, and repeated experiments are carried out. And comparing the accuracy of the simulation result and the size of the consumed resource when the bandwidth m of each channel is changed, and determining the optimal circuit design scheme.

And step two, inputting the signal to be detected into n channels simultaneously, reserving different signal frequencies by band-pass filters at the front ends of different channels, and then mixing the filtered signal with a local oscillator signal. If the signal at a certain time is,

then for this moment in timeFrequency of ω _t After the signals are subjected to band-pass filtering, signals with at most two channels are reserved, and subsequent frequency mixing processing is continued. Wherein the filter range of the front-end band-pass filter of the k channel is,

ω _k ≤ω≤ω _k +m (5)

assuming that the channel signal is reserved, the local oscillator signal in the frequency mixing module is,

f _k (t)＝A _k cos(ω _k t) (6)

the signal to be measured and the local oscillator signal are simultaneously input into the frequency mixer, and the output signal comprises two input components such as sum frequency, difference frequency, higher harmonic and the like due to the nonlinear characteristics of current and voltage in a circuit of the frequency mixer. According to the signal to be measured and the local oscillator signal represented by the equations (4) and (6), the output signal is,

the output signal is passed through a low-pass filter or a suitable frequency-selecting network, and the frequency is retained to be omega _t -ω _k Of the signal component (c).

And step three, generating an actual high dynamic impact signal by an impact machine, inputting the signal to be detected into an actual frequency reduction circuit, retaining low-frequency signal components after band-pass filtering, frequency mixing and frequency selection, realizing dynamic filtering and impedance matching by an operational amplifier, then sampling the generated differential analog signal by using an analog-to-digital converter through a single-ended to differential chip, and storing the acquired result in DDR 3. The whole acquisition process and the storage and uploading of subsequent data are controlled by receiving an instruction of an upper computer through a USB communication module, and the data are finally transmitted by utilizing an Ethernet.

And step four, processing the acquired data. Firstly, the whole impact process is recovered, because of the working mode of multipath parallel frequency-reducing acquisition, 1 or 2 channels exist output at any time, when the signal frequency is in the crossing range of the two channels, the two channels can acquire signals, for the sampling result, only one signal needs to be reserved for analysis, in the process of simulating the signal and testing the actual circuit, the absolute frequency error delta of the two channels under the same input signal is compared,

Δ＝ω _re -ω _th (8)

recording a channel with a smaller absolute error delta, and reserving a channel signal during recovery so as to recover the frequency of the acquired signal in the whole dynamic impact process; secondly, performing Hilbert-Huang transform on the synthesized signal, solving the instantaneous frequency of the signal, decomposing the acquired non-stationary time-varying signal into an eigenmode function by empirical mode decomposition,

wherein, c _i (t) is the decomposed N eigenmode functions, r _N (t) is a residual signal, because the high dynamic impact signal to be measured is a narrow-band signal, a component with an amplitude value obviously larger than other eigenmode functions exists in the decomposition result, the component contains most information of the signal to be measured, the instantaneous frequency of the signal can be obtained by performing Hilbert transform on the component, and if the d-th component is a target component, the c-th component is _d (t) performing Hilbert transform to obtain an analytical function thereof,

Y(t)＝c _d (t)+jH[c _d (t)]＝a(t)e ^jθ(t) (10)

in the formula (I), the compound is shown in the specification,

is the instantaneous amplitude of the signal and,

is the instantaneous phase of the signal, the instantaneous frequency of the signal can be solved by taking the derivative of the instantaneous phase,

finally, the actual frequency of the signal to be measured is obtained by combining the local oscillator signal, and according to the frequency mixing principle, if the calculated k channel signal frequency is omega _d (t), then the actual frequency is,

ω _re ＝ω _d (t)+ω _k (12)

thereby realizing the measurement of the frequency of the high dynamic impact signal.

(III) advantageous effects

The method has the advantages that the number of channels and the frequency of the local oscillator signal input during measurement are determined according to the actual signal to be measured in an analog simulation mode, so that the balance between difficulty and cost in signal acquisition is ensured; according to the number of the selected channels, other designs such as filter parameters are designed, so that the integrity of subsequent data recovery is facilitated; the signal is subjected to frequency mixing processing, and the high-frequency signal is reduced to a lower frequency, so that compared with the traditional direct acquisition method, the sampling rate is effectively reduced, the design requirement on a circuit is reduced compared with the original high-frequency signal, the data volume is greatly reduced, and the subsequent storage and transmission are facilitated; the method adopts a parallel mode, and the signals are simultaneously input into a plurality of channels, so that the problem that the signals cannot be captured due to short time is avoided, and the real-time sampling of the impact signals is realized; resolving the signal by using Hilbert-Huang transform due to the narrow-band characteristic of the signal, and obtaining the impact velocity of the projectile body through the frequency of the signal; the multichannel mixer circuit can be customized according to the actual signal frequency and the requirement of the test range, has better robustness and stability, and has wide application prospect.

Drawings

FIG. 1 is a flow chart of a frequency resolution method for high dynamic impact signals.

FIG. 2 is a typical block diagram of a frequency resolution system for high dynamic impact signals.

Wherein, 101 band-pass filter, 102 frequency-reducing module; the acquisition module comprises a 103 analog-to-digital conversion module, a 104DDR3 storage module, a 105USB communication module, a 106 Ethernet transmission module, a 107 computer and a 108 frequency calculation module.

Fig. 3 is a high dynamic impact signal acquired.

FIG. 4 is the empirical mode decomposition of the maximum impact velocity signal.

Fig. 5 is the instantaneous frequency for maximum speed.

Detailed Description

The present invention is further illustrated by the following examples. Fig. 1 is a flow chart of a frequency resolving method of a high dynamic impact signal, and fig. 2 is a typical structure diagram of a system. The procedure performed in connection with one example is as follows:

step one, doppler frequency shift signals generated by grating diffraction are converted into electric signals, the frequency can reach 90MHz at most, original signals are designed in the simulation process,

x ₀ ＝sin[2π(20×10 ³ +0.5×10 ¹¹ t)t] (1)

random noise with the mean value of 0 and the variances of 0.15, 0.25 and 0.35 is added to the original signal, and the number of channels is determined to be 6 by comparing the frequency errors of the acquired signal and the original signal. And simulating different filter types and orders, and finally determining that the passable frequency ranges of each channel are 0-20MHz, 15-35MHz, 30-50MHz, 45-65MHz, 60-80MHz and 75-95MHz in sequence, wherein the filter is a Chebyshev 24-order filter.

And secondly, simultaneously inputting signals to be detected into 6 channels, selecting signals of a specific frequency band by using a 101 band-pass filter, inputting the signals into a 102 frequency reduction module for preliminary processing, reducing the frequency of the signals, continuously transmitting the signals to a 103 analog-to-digital conversion module for preprocessing and real-time sampling, storing the acquired results into a 104DDR3 storage module, controlling the acquisition and data storage and uploading processes by a 107 computer through a 105USB communication module, and finally uploading the stored acquired data to a 107 computer through a 106 Ethernet transmission module to realize further resolving.

And step three, generating the local oscillation signals in the frequency reduction process by using an on-chip DDS chip, so that the miniaturization of the acquisition system can be ensured, wherein the chip is selected as AD9910, and the signals are amplified by using a high-speed operational amplifier AD 4857. The filtered signal to be measured and the local oscillator signal are simultaneously input into a multiplier AD835, and after operation, a difference frequency signal is reserved by utilizing low-pass filtering LT 6600. The filtered analog signal is converted into a differential signal through a single-end conversion chip, the bias level of the signal is adjusted, and common-mode noise is suppressed. And finally, a 16-bit double-channel analog-to-digital converter AD9650 is used for sampling the differential signal, the chip can realize the sampling rate of 100MHz, and the signal within 20MHz after frequency reduction can be effectively acquired. The collected digital signals are transmitted to 104DDR3 for storage, and can be transmitted to 107 computers for storage through 106 Ethernet. The acquisition process and the data storage and uploading process can be controlled by an upper computer, and the instruction is sent by a 105USB communication module.

And step four, resolving the acquired data by a 108 frequency resolving module. Firstly, restoring the signal to obtain a complete signal acquisition result. Then performing Hilbert-Huang transformation on the data, and decomposing the signal into a plurality of eigenmode functions by empirical mode decomposition; each component is subjected to hilbert transform, and the instantaneous frequency is obtained by using a formula. And finally, calculating the actual Doppler frequency shift signal frequency according to the selected local oscillation signal and the frequency mixing principle.

The above description of the invention and its embodiments is not intended to be limiting, and the illustrations in the drawings are intended to represent only one embodiment of the invention. Without departing from the spirit of the invention, it is within the scope of the invention to design the structure or the embodiment similar to the technical solution without creativity.

Claims (3)

1. A frequency resolving method and a system of high dynamic impact signals are disclosed, the system comprises a frequency mixing module, a signal acquisition module and a frequency resolving module, and is characterized in that the channel number and the local oscillation signal frequency of a circuit to be detected in different frequency ranges are designed in a targeted manner, the frequency mixing processing is carried out on the signal to be detected in the acquisition process so as to reduce the frequency of a high-frequency signal, and therefore the system can acquire the signal at a lower sampling rate, and meanwhile, a plurality of channels are adopted to carry out parallel processing and sampling on the signal, so that the impact signal is captured; the signal is firstly divided into a plurality of different frequency bands by a multi-channel mixing mode and the frequency is reduced, then the difference frequency signal of the low frequency is reserved for the next step of collection and storage, and finally the instantaneous frequency is solved after the signal uploaded to the computer is synthesized and compensated.

2. The method and system according to claim 1, wherein the number of channels of the front-end down-conversion circuit and the local oscillation frequency of each channel are determined by simulation based on the actual signal to be measured, the original signal to be measured is simulated,

wherein the amplitude A of the signal _t Frequency omega _t And phase

Respectively, over time t, frequency range omega ₀ ＜ω _t ≤ω _max ，

M＝ω _max -ω ₀ (2)

That is, M is the frequency bandwidth of the signal in the whole impact process, the signal is simultaneously input into n channels, the front end of each channel is a passive band-pass filter, the pass-band ranges of the filters are different,

the frequency ranges of all channels are combined to cover the bandwidth of the signal to be measured, the passband frequency is gradually increased from the channel 1 to the channel n, and in order to avoid the problem that the signal of the frequency at the critical position cannot be collected, the frequency ranges which can be passed by two adjacent channels have certain overlap,

if the frequency bandwidth of the signal which can pass through each channel in the frequency reducing process is m, the number n of the channels is selected to be larger than m

Then the passable frequency for each channel is,

the signals screened by the band-pass filter are mixed with the local oscillator signals, the local oscillator signal frequency of each channel is different due to the difference of the pass band frequency of the band-pass filter and is set as the minimum value of the pass band frequency, and for the kth channel, the local oscillator signal frequency is omega _k If, at a certain moment, the signal of the k-channel is filtered by the band-pass filter, the k-channel signal can be represented as,

A′ _t is the amplitude of the signal after being attenuated by the filter, the local oscillator signal of the k channel is,

f _k (t)＝A _k cos(ω _k t) (7)

the band-pass filtered signal is mixed with the local oscillator signal, and due to the nonlinear characteristics of current and voltage in the mixer circuit, the output signal includes components of sum frequency, difference frequency, higher harmonic and the like of two inputs, so that the output signal is,

after the output signal passes through a low-pass filter, the frequency is kept to be omega _t -ω _k Signal division ofAnd thus the signal frequency is reduced, random noise is added to the simulated signal to be measured, so that the signal to be measured is,

wherein randn is random noise, b represents the variance of random noise, b, frequency bandwidth m and channel number n are changed, the deviation of the acquired signal frequency and a theoretical value is analyzed, taking k channel as an example, the frequency theoretical value is,

ω _th ＝ω _t -ω _k (10)

the frequency of the collected signal is omega _re Then the relative error is,

and selecting the result with the minimum error as the optimal design scheme by comparing the relative error.

3. The method and the system for resolving the frequency of the high dynamic impact signal according to claim 1, wherein the signal recovery and processing comprises the following steps:

firstly, the whole impact process is recovered, because of the working mode of multipath parallel frequency-reducing acquisition, 1 or 2 channels exist for output at any time, when the signal frequency is in the crossing range of two channels, two channels can acquire signals, therefore, the sampling result only needs to keep one signal for analysis, in the process of simulating the signal and testing the actual circuit, the absolute frequency error delta of the two channels under the same input signal is compared,

Δ＝ω _re -ω _th (12)

recording a channel with a smaller absolute error delta, and reserving a channel signal during recovery so as to recover the frequency of the acquired signal in the whole dynamic impact process;

secondly, the synthesized signal is subjected to Hilbert-Huang transform, the instantaneous frequency of the signal is solved, the acquired non-stationary time-varying signal is decomposed into an eigenmode function by empirical mode decomposition,

wherein, c _i (t) is the decomposed N eigenmode functions, r _N (t) is a residual signal, because the high dynamic impact signal to be measured is a narrow-band signal, a component exists in the decomposed eigenmode function and contains most frequency information of the signal to be measured, the instantaneous frequency of the signal can be obtained by performing Hilbert transform on the component, and if the d-th component is a target component, the instantaneous frequency of the signal is obtained by performing Hilbert transform on the d-th component _d (t) performing Hilbert transform to obtain an analytical function thereof,

Y(t)＝c _d (t)+jH[c _d (t)]＝a(t)e ^jθ(t) (14)

in the formula (I), the compound is shown in the specification,

is the instantaneous amplitude of the signal and,

is the instantaneous phase of the signal, the instantaneous frequency of the signal can be calculated by taking the derivative of the phase,

finally, the actual frequency of the signal to be measured is obtained by combining the local oscillator signal, and according to the frequency mixing principle, if the calculated k channel signal frequency is omega _d (t), then the actual frequency is,

ω _re ＝ω _d (t)+ω _k (16)

thereby realizing the measurement of the frequency of the high dynamic impact signal.

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