CN114460362A - Ultra-wideband digital instantaneous frequency measurement method based on three-channel undersampling - Google Patents
Ultra-wideband digital instantaneous frequency measurement method based on three-channel undersampling Download PDFInfo
- Publication number
- CN114460362A CN114460362A CN202210083137.2A CN202210083137A CN114460362A CN 114460362 A CN114460362 A CN 114460362A CN 202210083137 A CN202210083137 A CN 202210083137A CN 114460362 A CN114460362 A CN 114460362A
- Authority
- CN
- China
- Prior art keywords
- frequency
- channel
- sampling
- sub
- band
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R23/00—Arrangements for measuring frequencies; Arrangements for analysing frequency spectra
- G01R23/02—Arrangements for measuring frequency, e.g. pulse repetition rate; Arrangements for measuring period of current or voltage
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F17/00—Digital computing or data processing equipment or methods, specially adapted for specific functions
- G06F17/10—Complex mathematical operations
- G06F17/14—Fourier, Walsh or analogous domain transformations, e.g. Laplace, Hilbert, Karhunen-Loeve, transforms
- G06F17/141—Discrete Fourier transforms
- G06F17/142—Fast Fourier transforms, e.g. using a Cooley-Tukey type algorithm
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Mathematical Physics (AREA)
- Engineering & Computer Science (AREA)
- Computational Mathematics (AREA)
- Mathematical Analysis (AREA)
- Mathematical Optimization (AREA)
- Pure & Applied Mathematics (AREA)
- Data Mining & Analysis (AREA)
- Theoretical Computer Science (AREA)
- Discrete Mathematics (AREA)
- Algebra (AREA)
- Databases & Information Systems (AREA)
- Software Systems (AREA)
- General Engineering & Computer Science (AREA)
- Measuring Frequencies, Analyzing Spectra (AREA)
Abstract
The invention discloses an ultra wide band instantaneous frequency measurement method based on a three-channel under-sampling technology, which can realize monitoring on a plurality of signals in an ultra wide band frequency spectrum range. After being amplified and filtered, radio frequency signals are directly input into three sampling channels for sampling, the sampling rates of all the channels of signals are different, short-time window weighting is adopted, the frequency of the radio frequency in the short-time window folded into the first Nyquist zone of each sampling channel is calculated by using a real signal double FFT point method, and then the radio frequency without ambiguity can be solved by using a sub-band segmentation ambiguity removing method. The invention can realize instantaneous frequency measurement of signals within the range of 0-18 GHz within 200ns, and the frequency measurement precision is within 1 MHz.
Description
Technical Field
The invention relates to the technical field of electromagnetic signal reconnaissance.
Background
The instantaneous frequency measurement technology gradually matures after decades of development. The early instantaneous frequency measurement technology mainly adopts a multi-channel analog delay line instantaneous frequency measurement mode, the equipment is complex, and the frequency measurement performance is easily influenced by the external environment. With the application of high-performance digital processing chips and the research of corresponding signal processing technologies, the instantaneous frequency measurement technology develops towards the direction of broadband and digitization.
Common digital instantaneous frequency measurement techniques include single-bit frequency measurement, optical sampling frequency measurement, digital channelized frequency measurement, and the like. A single-bit instantaneous frequency measurement technology is proposed in Analysis and characterization of a monobit receiver for electronic device far' (Grajal J, IEEE trans. Aerosp. Electron. Syst,2003, vol.39, No.1, pp.244-258), and has the advantages of simple structure, low cost, large instantaneous bandwidth and the like, but the data bit width is small, the instantaneous dynamic is small, and a plurality of simultaneously arriving signals cannot be processed; photonic-based broadband and microwave induced frequency-to-phase-slope mapping (J.Z.Shi, F.D.Zhang, D.Ben, et al IEEE trans.Microw.Therey Tech.,2019, vol.67, No.2, pp.544-552) proposes an optical sampling frequency measurement technology, the instantaneous bandwidth can reach dozens of GHz, but the frequency measurement precision is poor, and the requirements of electronic reconnaissance and electronic interference guidance cannot be met; a fast ELINT receiver design' Proceedings of the 13th European radio Conference (A. Alisslan and K. Yegin. London, UK, IEEE,2016, pp.217-220) proposes a digital channelized frequency measurement technology with a super-heterodyne structure, obtains a larger working bandwidth by adopting a super-heterodyne mode, has the advantages of high channelized sensitivity, high flexibility of distinguishing a plurality of simultaneously arriving signals and digitalization, is most widely applied in electronic reconnaissance, but the instantaneous bandwidth can only reach half of a sampling rate at most, and cannot realize high-probability interception of signals in a wide frequency band range.
With the use of a large number of electronic devices in a battlefield, the signal density is higher and higher, the electromagnetic environment of the battlefield is increasingly complex, the types, power, bandwidth and modulation modes of signals are complex and changeable, and the coverage range of frequency is wider and wider, so that the frequency measurement receiver is urgently required to have a larger instantaneous bandwidth to obtain higher interception probability and higher frequency resolution and instantaneous dynamic range, and the existing technology is generally difficult to meet the requirements.
Disclosure of Invention
In order to solve the technical problem, the invention provides an ultra-wideband digital instantaneous frequency measurement method based on three-channel undersampling, which is realized by the following technical scheme:
step S1, dividing the input radio frequency signal into three paths to directly carry out undersampling;
step S2, segmenting the three paths of sampling signals by adopting a short time window, and assuming that the signals are stable in the short time window;
step S3, estimating the frequency value of the radio frequency folded to the first Nyquist zone of each sampling channel by using a real signal double FFT point frequency estimation method;
in step S4, the frequency of the rf signal without ambiguity is resolved by frequency disambiguation method using frequency band division.
Preferably, the three-way sampling signal in step S2 uses a short time window function with the same length.
Preferably, the real signal double-FFT-point frequency estimation comprises performing zero-padding FFT on three signals respectively, wherein the number of FFT points is NfftSearching for a peak point, denoted as kp1，kp2，kp3Completing coarse frequency measurement; and finishing accurate frequency measurement by using the values of the next large peak points on the two sides of the peak point, wherein the frequency measurement formula is as follows:
in the formula (I), the compound is shown in the specification,
is a frequency offset value, NmThe number of short time window samples for the mth sampling channel,
for N after zero paddingfftResult of point FFT operation, betamIs and Nm、NfftThe relevant constants, k, obtained in advance by simulationpmIs the position of the peak point after FFT, fsmIs the sampling rate.
Preferably, the deblurring of the band segmentation comprises: first according to fs1，fs2，fs3Will be [0, fmax]Dividing the signal into X sub-bands, each sub-band corresponding to a unique set of folding parameters, and estimating the fuzzy frequency fmObtaining a total error value corresponding to each sub-band, and finally searching the sub-band with the minimum error, assuming that the number of the sub-band is l, the frequency of the input signal can be represented as:
the invention has the advantages that:
(1) the radio frequency signal is directly sampled, the sampling is as close to the antenna as possible, a large number of analog front-end devices are avoided, and the radio frequency signal sampling device is simple in structure and good in flexibility;
(2) the ultra-wideband instantaneous frequency measurement is realized by replacing a high-speed ADC with a plurality of low-speed ADCs, the processing pressure of a digital signal processing unit is reduced, and meanwhile, the ultra-wideband instantaneous frequency measurement has higher sampling digit and can obtain a higher instantaneous dynamic range;
(3) at present, interpolation DFT algorithms such as Rife, Jacobsen, Candida and the like are often adopted to calculate frequency offset values, the estimation errors of the algorithms fluctuate greatly under different frequency offsets, and the calculated amount is relatively large;
(4) at present, a Robust Chinese Remainder Theorem (RCRT) algorithm is often adopted to perform ambiguity resolution operation, the calculated amount is large, and the ambiguity resolution accuracy is not high.
The invention can ensure that the frequency measurement time is not more than 200ns and the frequency measurement precision is within the range of 1 MHz.
Drawings
Fig. 1 is a structural block diagram of ultra-wideband undersampling instantaneous frequency measurement.
Detailed Description
The technical scheme of the invention is further described in detail in the following with reference to the attached drawings.
The invention employs three sampling channels. As shown in fig. 1, the rf signal is amplified, power divided, sampled and held, and then input to three sampling channels for digitization respectively. The digital part mainly comprises a frequency measurement part and a frequency resolution part, wherein the frequency measurement part firstly adds a short time window to an input signal, then carries out zero filling FFT operation on the signal in the window, searches a peak value to finish rough frequency measurement, estimates frequency offset by utilizing amplitude values of two next-largest peak values at the left and right of the peak value to finish fine frequency measurement, and thus obtains the frequency of a radio frequency signal folded into a first Nyquist zone of each sampling channel; and the ambiguity removing part divides the frequency band to be detected into a plurality of sub-bands by adopting a frequency band division method, each sub-band corresponds to a unique group of folding parameters, the error corresponding to each sub-band is calculated according to the sampling rate and the ambiguity frequency value of each channel, the sub-band with the minimum error is selected as the sub-band where the radio frequency signal frequency is located, and the input signal frequency is calculated by utilizing the folding parameters of the sub-band.
The following describes the present invention in detail with reference to specific examples, assuming that the frequency range of the input signal is [0,18000MHz "), the three-channel sampling frequencies are 1800MHz, 1900MHz, and 2000MHz, respectively, and the short-time window function width is 10ns, then the number of sample points contained in the short-time window of the three channels is: 18. 19, 20, setting the number of FFT points to Nfft128, the slope constant for each channel is β1＝0.8741，β2＝0.7829，β3＝0.7050。
It can be analyzed that the frequency range of the input signal can be divided into 54 sub-bands. Setting the frequency of the input signal to be 13475MHz, and obtaining folding frequencies corresponding to three subchannels through interpolation FFT operation in step 3: 875.5MHz, 174.1MHz, and 525.3MHz, the input signal frequency is in the 42 th sub-band after step 4, and the folding parameters corresponding to the three channels are: b1＝7，d1＝1，b2＝7，d2＝1，b3＝7，d3The input signal frequency according to step 5 is-1: 13474.7 MHz.
Claims (4)
1. A ultra-wideband digital instantaneous frequency measurement method based on three-channel undersampling is characterized in that:
step S1: dividing an input radio frequency signal into three paths to directly perform undersampling;
step S2: segmenting the three sampling signals by adopting a short time window, and assuming that the signals are stable in the short time window;
step S3: estimating the frequency value of the radio frequency folded to the first Nyquist zone of each sampling channel by adopting a real signal double FFT point frequency estimation method;
step S4: and resolving the radio frequency signal frequency without ambiguity by adopting a frequency ambiguity resolving method of frequency band division.
2. The ultra-wideband digital instantaneous frequency measurement method based on three-channel undersampling according to claim 1, characterized in that: in the step S2, short-time window functions with the same length are adopted for the three sampling signals.
3. The ultra-wideband digital instantaneous frequency measurement method based on three-channel undersampling according to claim 1, characterized in that: the real signal double-FFT point frequency estimation method in step S3 includes:
in the formula (I), the compound is shown in the specification,
is a frequency offset value, NmThe number of short time window samples for the mth sampling channel,
for supplementingAfter zero NfftResult of point FFT operation, betamIs and Nm、NfftThe relevant constants, k, obtained in advance by simulationpmIs the position of the peak point after FFT, fsmIs the sampling rate.
4. The ultra-wideband digital instantaneous frequency measurement method based on three-channel undersampling according to claim 4, characterized in that: the frequency deblurring method in the step S4 includes: the relationship between the input signal frequency and the blur frequency folded into the first nyquist zone can be expressed as:
fc＝bmfsm+dmfm,0≤fm≤fsm/2,bm＝0,1,2...Bm,dm＝±1,m＝1,2,3
in the formula, bm，dmIs a folding parameter; wherein b ismIs a non-negative integer having a maximum value
fmaxIs the upper limit of the measurable frequency range; according to fs1，fs2，fs3Will be [0, fmax]Dividing the signal into X sub-bands, each sub-band corresponding to a unique set of folding parameters, and estimating the fuzzy frequency fmObtaining a total error value corresponding to each sub-band, where the sub-band with the smallest error is the sub-band where the input signal is located, and assuming that the number of the sub-band is l, the frequency of the input signal may be represented as:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210083137.2A CN114460362A (en) | 2022-01-25 | 2022-01-25 | Ultra-wideband digital instantaneous frequency measurement method based on three-channel undersampling |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210083137.2A CN114460362A (en) | 2022-01-25 | 2022-01-25 | Ultra-wideband digital instantaneous frequency measurement method based on three-channel undersampling |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN114460362A true CN114460362A (en) | 2022-05-10 |
Family
ID=81411518
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210083137.2A Pending CN114460362A (en) | 2022-01-25 | 2022-01-25 | Ultra-wideband digital instantaneous frequency measurement method based on three-channel undersampling |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114460362A (en) |
-
2022
- 2022-01-25 CN CN202210083137.2A patent/CN114460362A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN109387813B (en) | High-precision frequency measurement method based on broadband radar signal reception | |
| CN103941087B (en) | The frequency measurement method of the high-frequency cosine signal under lack sampling speed and device thereof | |
| CN104007316B (en) | A kind of High Precision Frequency method under lack sampling speed and measuring instrument thereof | |
| CN104122444B (en) | All-digital IF spectrum analyzer and frequency spectrum analysis method | |
| CN107329127B (en) | A kind of phase linearity analysis method and system for radar system DBF Function detection | |
| CN113965217B (en) | Double-channel single-channel S/C/X three-band broadband single-bit digital frequency measurement receiver | |
| CN107561357B (en) | High-precision instantaneous frequency measurement method and device based on channelization | |
| CN116819185B (en) | Digital phase discrimination method and system based on channelization in complex electromagnetic environment | |
| CN109407501B (en) | Time interval measuring method based on relevant signal processing | |
| CN111337746A (en) | Radio frequency signal detection positioning method | |
| JP2006525503A (en) | Digital electronic support device | |
| CN109655775B (en) | Amplitude frequency sweep multi-scale calibration method and device for arbitrary waveform generator | |
| CN113960523A (en) | Universal ultra-wideband correction direction-finding method and system based on FPGA | |
| CN108776261B (en) | Multichannel under-sampling frequency measurement method for large-bandwidth frequency hopping narrow-band signal | |
| CN114460362A (en) | Ultra-wideband digital instantaneous frequency measurement method based on three-channel undersampling | |
| Li et al. | Multi-band superresolution multipath channel path delay estimation for CIR-based localization | |
| CN115792372A (en) | Multichannel ultra-wideband undersampling instantaneous frequency measurement method | |
| CN107171748B (en) | Undersampled multi-array collaborative frequency measurement and direct positioning method | |
| CN105634494B (en) | The method of radiofrequency signal analog-to-digital conversion | |
| US7352827B2 (en) | Multichannel simultaneous real time spectrum analysis with offset frequency trigger | |
| CN212905422U (en) | Broadband digital frequency measurement module | |
| CN109581067B (en) | Capacitance measuring device based on FPGA high-speed receiver | |
| CN112152735A (en) | Broadband real-time APD (avalanche photo diode) measuring method based on STFFT (fast Fourier transform algorithm) | |
| Braun et al. | Requirements and solutions for emission measurements in time-domain according to international EMC standards | |
| CN109495187A (en) | A kind of TOA essence estimation method based on Hilbert transform |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| CB02 | Change of applicant information | ||
| CB02 | Change of applicant information |
Address after: 210003 No. 346, Zhongshan North Road, Jiangsu, Nanjing Applicant after: 724 Research Institute of China Shipbuilding Corp. Address before: 210003 No. 346, Zhongshan North Road, Jiangsu, Nanjing Applicant before: 724TH RESEARCH INSTITUTE OF CHINA SHIPBUILDING INDUSTRY Corp. |