Microwave Photon-Based Wide-Band Signal Reception and Identification Method and Device

Abstract

The present invention relates to the field of microwave photonics technology, and particularly to a wide-band signal receiving and identifying method and device based on microwave photonics. An electromagnetic signal to be identified is received by a signal receiving unit; a signal generating unit generates two sampling pulse signals, namely optical carrier signals; the electromagnetic signal to be identified is loaded onto the optical carrier signals for intensity modulation to obtain a first modulated optical signal and a second modulated optical signal; then, a signal processing unit respectively preprocesses the first modulated optical signal and the second modulated optical signal to obtain corresponding first digital signal and second digital signal; finally, a reconstruction and identification unit performs identification processing on the first digital signal and the second digital signal, and the frequency corresponding to the electromagnetic signal to be identified can be obtained. And through testing, according to the wide-band signal receiving and identifying device based on microwave photonics provided by the present invention, electromagnetic signals within a relatively wide frequency band range can be identified.

Description

Technical Field

[0001] The present invention relates to the field of microwave photonics technology, and in particular to a wide-band signal receiving and identifying method and device based on microwave photonics. Background Art

[0002] With the development of microwave photonics technology, the processing of large-bandwidth signals based on microwave photonics technology has been widely applied in fields such as radar and communication. Among them, the microwave photon receiver is an important part of the radar and has the functions of signal reception and processing. Due to the existence of the electronic bottleneck, the receiving bandwidth and sensitivity of the traditional electronic receiver are both limited. Especially for multi-band and wide-band agile frequency signals, the frequency band covered by the electronic receiver is limited and the scanning speed is slow, and it is impossible to receive burst signals in the wide-band range in real time.

[0003] In order to improve the detection and identification of wide-band electromagnetic signals by the microwave photon receiving system, in the prior art, an 8 GHz actively mode-locked laser is used, combined with a neural network algorithm, to achieve down-conversion of wide-band signals and improvement of the signal-to-noise ratio. However, the neural network algorithm increases the hardware cost and computational pressure of the system, and does not specifically involve frequency identification. Although using a single high-repetition-rate passively mode-locked laser as the light source of the microwave photon receiving device can provide a relatively wide Nyquist zone and expand the instantaneous bandwidth range of the identifiable electromagnetic signals to a certain extent, the identifiable frequency range is still limited within half of the laser repetition frequency, and there is still a problem that the signal frequency is ambiguous and cannot be identified for wide-band or high-frequency electromagnetic signals. Summary of the Invention

[0004] The present invention provides a wide-band signal receiving and identifying method and device based on microwave photonics to solve the technical problem that the frequency of wide-band or high-frequency electromagnetic signals cannot be identified in the prior art.

[0005] On the one hand, the present invention provides a wide-band signal receiving and identifying device based on microwave photonics, including: a signal generating unit, a signal receiving unit, a signal modulating unit, a signal processing unit, and a reconstruction and identification unit;

[0006] The signal receiving unit is used to receive the electromagnetic signal to be identified;

[0007] The signal generating unit is used to generate a continuous and uniform sampling pulse signal and a non-uniform sampling pulse signal with frequency jitter, and the above two signals are both called optical carrier signals;

[0008] The signal modulating unit is used to load the electromagnetic signal to be identified onto the uniform sampling pulse signal and perform intensity modulation to obtain a first modulated optical signal; and load the electromagnetic signal to be identified onto the non-uniform sampling pulse signal and perform intensity modulation to obtain a second modulated optical signal;

[0009] The signal processing unit is configured to preprocess the first modulated optical signal and the second modulated optical signal respectively to obtain corresponding first digital signal and second digital signal;

[0010] The reconstruction and recognition unit is configured to perform recognition processing on the first digital signal and the second digital signal to obtain the frequency corresponding to the electromagnetic signal to be recognized.

[0011] According to a wide-band signal receiving and recognizing device based on microwave photon provided by the present invention, the signal generating unit includes a mode-locked laser and an acousto-optic frequency shifter;

[0012] The mode-locked laser is configured to generate the continuous and uniform sampling pulse signal; the acousto-optic frequency shifter is configured to add a preset jitter frequency to the sampling pulse signal to obtain the non-uniform sampling pulse signal.

[0013] According to a wide-band signal receiving and recognizing device based on microwave photon provided by the present invention, the signal receiving unit includes an antenna and a first signal amplifier;

[0014] The antenna is configured to receive the electromagnetic signal to be recognized; the first signal amplifier is configured to perform power amplification processing on the electromagnetic signal to be recognized.

[0015] According to a wide-band signal receiving and recognizing device based on microwave photon provided by the present invention, the signal processing unit includes a photodetector, a low-pass filter, a second signal amplifier and an analog-to-digital converter;

[0016] The photodetector is configured to detect the first modulated optical signal and convert it into a first electrical signal; the low-pass filter is configured to perform low-pass filtering processing on the first electrical signal to obtain a second electrical signal; the second signal amplifier is configured to perform power amplification processing on the second electrical signal to obtain a third electrical signal; the analog-to-digital converter is configured to perform analog-to-digital conversion processing on the third electrical signal to obtain the first digital signal;

[0017] The photodetector is further configured to detect the second modulated optical signal and convert it into a fourth electrical signal; the low-pass filter is further configured to perform low-pass filtering processing on the fourth electrical signal to obtain a fifth electrical signal; the second signal amplifier is further configured to perform power amplification processing on the fifth electrical signal to obtain a sixth electrical signal; the analog-to-digital converter is configured to perform analog-to-digital conversion processing on the sixth electrical signal to obtain the second digital signal.

[0018] According to a wide-band signal receiving and recognizing device based on microwave photon provided by the present invention, the reconstruction and recognition unit is specifically configured to:

[0019] Obtain a first sampling frequency component according to the first digital signal;

[0020] Obtain a second sampling frequency component according to the second digital signal;

[0021] Determine the aliasing region number where the electromagnetic signal to be identified is located according to the first sampling frequency component, the second sampling frequency component, and a preset jitter frequency;

[0022] Determine the Nyquist region number corresponding to the electromagnetic signal to be identified according to the offset of the second sampling frequency component relative to the first sampling frequency component;

[0023] Calculate the frequency corresponding to the electromagnetic signal to be identified according to the first sampling frequency component, the second sampling frequency component, and the aliasing region number and Nyquist region number where the electromagnetic signal to be identified is located.

[0024] On the other hand, the present invention also provides a wideband signal receiving and identifying method based on microwave photonics, including:

[0025] Receive the electromagnetic signal to be identified;

[0026] Obtain a continuous and uniform sampling pulse signal and a non-uniform pulse signal with frequency jitter, and both of the above two signals are called optical carrier signals;

[0027] Load the electromagnetic signal to be identified onto the uniform sampling pulse signal and perform intensity modulation to obtain a first modulated optical signal; and load the electromagnetic signal to be identified onto the non-uniform pulse signal and perform intensity modulation to obtain a second modulated optical signal;

[0028] Perform preprocessing on the first modulated optical signal and the second modulated optical signal respectively to obtain corresponding first digital signal and second digital signal;

[0029] Perform identification processing on the first digital signal and the second digital signal to obtain the frequency corresponding to the electromagnetic signal to be identified.

[0030] According to the wideband signal receiving and identifying method based on microwave photonics provided by the present invention, the performing preprocessing on the first modulated optical signal and the second modulated optical signal respectively to obtain corresponding first digital signal and second digital signal includes:

[0031] Convert the first modulated optical signal into a first electrical signal; perform low-pass filtering processing on the first electrical signal to obtain a second electrical signal; perform power amplification processing on the second electrical signal to obtain a third electrical signal; perform analog-to-digital conversion processing on the third electrical signal to obtain the first digital signal;

[0032] Convert the second modulated optical signal into a fourth electrical signal; perform low-pass filtering on the fourth electrical signal to obtain a fifth electrical signal; perform power amplification on the fifth electrical signal to obtain a sixth electrical signal; perform analog-to-digital conversion on the sixth electrical signal to obtain the second digital signal.

[0033] According to a wide-band signal receiving and identifying method based on microwave photon provided by the present invention, the obtaining of an optical carrier signal with a non-uniform pulse sequence having frequency jitter includes:

[0034] Obtain a continuous and uniform sampling pulse signal;

[0035] Add a preset jitter frequency to the continuous and uniform sampling pulse signal to obtain the optical carrier signal.

[0036] According to a wide-band signal receiving and identifying method based on microwave photon provided by the present invention, the identifying process of the first digital signal and the second digital signal to obtain the frequency corresponding to the electromagnetic signal to be identified includes:

[0037] Obtain a first sampling frequency component according to the first digital signal;

[0038] Obtain a second sampling frequency component according to the second digital signal;

[0039] Determine the aliasing region serial number where the electromagnetic signal to be identified is located according to the first sampling frequency component, the second sampling frequency component and the preset jitter frequency;

[0040] Determine the Nyquist region serial number corresponding to the electromagnetic signal to be identified according to the offset amount of the second sampling frequency component relative to the first sampling frequency component;

[0041] Calculate the frequency corresponding to the electromagnetic signal to be identified according to the first sampling frequency component, the second sampling frequency component, and the aliasing region serial number and the Nyquist region serial number where the electromagnetic signal to be identified is located.

[0042] The present invention also provides an electronic device, including a memory, a processor, and a computer program stored on the memory and executable on the processor, and when the processor executes the program, it implements the wide-band signal receiving and identifying method based on microwave photon as described in any one of the above.

[0043] A computer program product, including a computer program, and when the computer program is executed by a processor, it implements the wide-band signal receiving and identifying method based on microwave photon as described in any one of the above.

[0044] The present invention also provides a non-transitory computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, it implements the method for receiving and identifying wide-band signals based on microwave photons as described in any one of the above.

[0045] The wide-band signal receiving and identifying device based on microwave photons provided by the present invention receives an electromagnetic signal to be identified through a signal receiving unit; generates an optical carrier signal through a signal generating unit, which are respectively a continuous and uniform sampling pulse signal and a non-uniform sampling pulse signal with frequency jitter; a signal modulation unit for loading the electromagnetic signal to be identified onto the uniform sampling pulse signal and performing intensity modulation to obtain a first modulated optical signal; and loading the electromagnetic signal to be identified onto the non-uniform sampling pulse signal with frequency jitter and performing intensity modulation to obtain a second modulated optical signal; then preprocessing the first modulated optical signal and the second modulated optical signal respectively through a signal processing unit to obtain corresponding first digital signal and second digital signal; finally, performing identification processing on the first digital signal and the second digital signal through a reconstruction and identification unit, and the frequency corresponding to the electromagnetic signal to be identified can be obtained. And through testing, according to the wide-band signal receiving and identifying device based on microwave photons provided by the present invention, high-frequency electromagnetic signals within a relatively wide frequency band range can be identified. Brief Description of the Drawings

[0046] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0047] Figure 1 It is a schematic diagram of the overall structure of the wide-band signal receiving and identifying device based on microwave photons provided by the embodiments of the present invention;

[0048] Figure 2 It is a schematic diagram of the specific structure of the wide-band signal receiving and identifying device based on microwave photons provided by the embodiments of the present invention;

[0049] Figure 3 It is a schematic diagram of the structure of the SESAM passive mode-locked fiber laser provided by the embodiments of the present invention;

[0050] Figure 4 It is a simulation timing diagram of the output of the SESAM passive mode-locked fiber laser provided by the implementation cases of the present invention;

[0051] Figure 5 It is a schematic diagram of post-sampling mixing of wide-band signals provided by the embodiments of the present invention;

[0052] Figure 6 One of the schematic diagrams of the radio frequency test signal frequency identification method provided by the embodiment of the present invention;

[0053] Figure 7 Two of the schematic diagrams of the radio frequency test signal frequency identification method provided by the embodiment of the present invention;

[0054] Figure 8 Three of the schematic diagrams of the radio frequency test signal frequency identification method provided by the embodiment of the present invention;

[0055] Figure 9 Four of the schematic diagrams of the radio frequency test signal frequency identification method provided by the embodiment of the present invention;

[0056] Figure 10 Five of the schematic diagrams of the radio frequency test signal frequency identification method provided by the embodiment of the present invention;

[0057] Figure 11 Six of the schematic diagrams of the radio frequency test signal frequency identification method provided by the embodiment of the present invention;

[0058] Figure 12 Schematic diagram of the identification effect of signals in the frequency range of 2.5 GHz to 4.9 GHz by using the identification device of the embodiment of the present invention;

[0059] Figure 13 Schematic diagram of the identification effect of signals in the frequency range of 5.1 GHz to 7.5 GHz by using the identification device of the embodiment of the present invention;

[0060] Figure 14 Schematic diagram of the flow of the wide-band signal receiving and identifying method based on microwave photon provided by the embodiment of the present invention. Detailed implementation manners

[0061] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions in the present invention will be clearly and completely described below with reference to the accompanying drawings in the present invention. Apparently, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present invention without creative efforts shall fall within the protection scope of the present invention.

[0062] To improve the detection and identification of wide-band electromagnetic signals by a microwave photon receiving system, in the embodiment of the present invention, the natural pulse sequence of a mode-locked laser is used to perform optical sampling on the electromagnetic signals to be identified. After optical sampling of wide-band or high-frequency electromagnetic signals, they can be down-converted to the Nyquist zone with a lower optical repetition frequency, so that only a low-speed electronic analog-to-digital converter can be used to achieve signal acquisition. After the acquired electrical signals are converted into digital signals, and then through data processing and calculation, the frequencies of the original wide-band or high-frequency electromagnetic signals can be reconstructed.

[0063] However, through further testing, the applicant found that the performance of the receiving device in receiving and identifying electromagnetic signals is closely related to the repetition frequency and sampling method of the light source used. However, using the continuous equal-time interval pulses of a mode-locked laser to uniformly sample electromagnetic signals cannot identify signals aliased within the Nyquist zone. Therefore, in the embodiments of the present invention, an idea of non-uniform sampling for frequency identification of broadband electromagnetic signals is proposed. At the same time, in order to meet the identification of a range of frequencies, an acousto-optic frequency shifter (including spatial optical path delay control) is added to the identification link in the embodiments of the present invention. Finally, the corresponding aliasing zone number and Nyquist zone number are determined according to the frequency jitter and offset, and then the frequency of the electromagnetic signal to be identified is determined to reconstruct the electromagnetic signal to be identified.

[0064] Figure 1 Please refer to the structural schematic diagram of the wide-band signal receiving and identifying device based on microwave photon provided by the embodiments of the present invention Figure 1 , and the identifying device includes: a signal generating unit 1, a signal receiving unit 2, a signal modulating unit 3, a signal processing unit 4, and a reconstruction and identification unit 5.

[0065] Among them, the signal receiving unit 2 is used to receive the electromagnetic signal to be identified. The signal generating unit 1 is used to generate a continuous and uniform sampling pulse signal and a non-uniform sampling pulse signal with frequency jitter, and both of the above two signals are optical carrier signals. The signal modulating unit 3 is used to load the electromagnetic signal to be identified onto the uniform sampling pulse signal, perform intensity modulation on the electromagnetic signal to be identified, and perform optical sampling (i.e., down-conversion processing) to obtain a first modulated optical signal; the signal modulating unit 3 is also used to load the electromagnetic signal to be identified onto the non-uniform sampling pulse signal and perform intensity modulation, and similarly, a second modulated optical signal of the electromagnetic signal to be identified can be obtained. The signal processing unit 4 is used to preprocess the first modulated optical signal and the second modulated optical signal respectively to obtain corresponding first digital signal and second digital signal. The reconstruction and identification unit 5 is used to perform identification processing on the first digital signal and the second digital signal, and then the frequency corresponding to the electromagnetic signal to be identified can be obtained.

[0066] Exemplarily, Figure 2 Please refer to the specific structural schematic diagram of the wide-band signal receiving and identifying device based on microwave photon provided by the embodiments of the present invention. As Figure 2 shown, the signal generating unit 1 of this embodiment includes a mode-locked laser 10 and an acousto-optic frequency shifter 11; the mode-locked laser 10 is used to generate a continuous and uniform sampling pulse signal; the acousto-optic frequency shifter 11 is used to add a preset jitter frequency to the sampling pulse signal, that is, the frequency jitter added to the original output uniform pulse sequence of the mode-locked laser 10, to obtain a non-uniform sampling pulse signal.

[0067] Optionally, the mode-locked laser 10 in this embodiment can adopt a high-repetition-rate mode-locked laser, which is generated by a SESAM (semiconductor saturable absorber mirror) passive mode-locked fiber laser. The central wavelength of the sampled pulse signal it emits is about 1560 nm, the repetition frequency is frep, the output power is greater than 10 mW, and it has an all-polarization-maintaining fiber structure. The acousto-optic frequency shifter 11 in this embodiment can generate a frequency jitter f of not less than 1 MHz d 。

[0068] Exemplarily, Figure 3 is a schematic structural diagram of the SESAM passive mode-locked fiber laser provided by the embodiment of the present invention. The overall mode-locked fiber laser adopts an ultra-short linear cavity structure. The repetition frequency of the laser is related to the linear cavity length. The calculation formula is: frep = c / 2NL. In this formula, c is the speed of light in vacuum, which is equal to 3×10 8 m / s, N is the refractive index of light, N is equal to 1.47, and L is the linear cavity length. Through calculation, it can be obtained that a 5 GHz repetition frequency corresponds to a linear cavity length of about 2 cm. As Figure 3 shown, the 980 nm pump light enters the polarization-maintaining erbium-doped gain fiber through a composite device (WDM / PM-ISO) of a wavelength division multiplexer and a polarization-maintaining isolator. The length of the gain fiber is 2 cm. To form a resonant cavity, a high-reflection film (DF) is coated on the input end of the gain fiber. The transmittance of the 980 nm pump light is >99%, and the reflectivity of the 1560 nm signal light is >99%. The output end of the gain fiber is coupled to the SESAM end face. The reflectivity of the SESAM for the 1560 nm signal light is >70%.

[0069] Figure 4 is a simulation timing diagram of the output of the SESAM passive mode-locked fiber laser provided by the embodiment of the present invention Figure 4 The interval between adjacent pulses in is 0.2 ns, corresponding to a repetition frequency of 5 GHz, which is also the optical sampling frequency of the microwave photon wideband signal receiving and identifying system. The range of the corresponding baseband Nyquist zone is fnyquist = [0, 2.5 GHz].

[0070] As Figure 2 shown, the signal receiving unit 2 in this embodiment includes an antenna 20 and a first signal amplifier 21; the antenna 20 is used to receive the electromagnetic signal to be identified, and the first signal amplifier 21 is used to perform power amplification processing on the received electromagnetic signal to be identified to compensate for the power loss of the electromagnetic signal to be identified during transmission.

[0071] Exemplarily, as Figure 2As shown in the figure, the signal modulation unit 3 of this embodiment includes an intensity modulator 31. The electromagnetic signal to be recognized is loaded onto the optical carrier signal through the intensity modulator 31, so as to realize optical sampling of the electromagnetic signal to be recognized using a uniform sampling pulse signal and a non-uniform sampling pulse signal.

[0072] Optionally, the operating bandwidth of the antenna 20 in this embodiment is greater than 10 GHz, the operating bandwidth of the first signal amplifier 21 is greater than 10 GHz, and the amplification gain is greater than 10 dB.

[0073] Exemplarily, as Figure 2 As shown in the figure, the signal processing unit 4 of this embodiment includes a photodetector 40, a low-pass filter 41, a second signal amplifier 42, and an analog-to-digital converter 43. Among them, the photodetector 40 is used to detect the first modulated optical signal output by the signal modulation unit 3, that is, to convert the optical signal into a first electrical signal. The low-pass filter 41 is used to perform low-pass filtering on the first electrical signal to obtain a second electrical signal. Optionally, the low-pass filter 41 has a high transmittance for frequencies in the Nyquist zone and cuts off for frequencies exceeding the Nyquist zone. For example, the low-pass filter 41 has a high transmittance for frequencies less than or equal to frep / 2 bandwidth and cuts off for frequencies greater than frep / 2. The second signal amplifier 42 is used to perform power amplification on the second electrical signal to obtain a third electrical signal. The analog-to-digital converter 43 is used to perform analog-to-digital conversion on the third electrical signal, that is, to convert the analog electrical signal into a digital signal recognizable by the processor, so as to obtain a first digital signal. In addition, the mode-locked laser 10 is also used to send its own repetition frequency to the analog-to-digital converter 43, and then to the reconstruction and recognition unit 5, so as to realize the time synchronization of the signal generation unit 1, the signal processing unit 4, and the reconstruction and recognition unit 5.

[0074] Similarly, the photodetector 40 is also used to detect the second modulated optical signal and convert it into a fourth electrical signal; the low-pass filter 41 is also used to perform low-pass filtering on the fourth electrical signal to obtain a fifth electrical signal; the second signal amplifier 42 is also used to perform power amplification on the fifth electrical signal to obtain a sixth electrical signal; the analog-to-digital converter 43 is used to perform analog-to-digital conversion on the sixth electrical signal to obtain a second digital signal.

[0075] Exemplarily, as Figure 2 As shown in the figure, the reconstruction and recognition unit 5 of this embodiment includes a data acquisition card 50 and a computer 51. Among them, the data acquisition card 50 is used to quantize and encode the first digital signal and the second digital signal, for example, convert them into binary signals recognizable by the processor. The computer 51 is used to analyze and process the converted first digital signal and second digital signal to obtain the frequency of the signal to be recognized, and then based on the recognized frequency, perform Fourier transform and comparison calculation on the collected digital signal to reconstruct the signal to be recognized.

[0076] For example, the reconstruction recognition unit 50 is specifically configured to:

[0077] Obtain a first sampling frequency component from the first digital signal, that is, analyze the first digital signal to obtain the frequency of the sampling signal corresponding to the first digital signal; obtain a second sampling frequency component from the second digital signal; determine the aliasing region number where the electromagnetic signal to be recognized is located according to the first sampling frequency component, the second sampling frequency component, and a preset jitter frequency; determine the Nyquist region number corresponding to the electromagnetic signal to be recognized according to the offset amount of the second sampling frequency component relative to the first sampling frequency component; calculate the frequency corresponding to the electromagnetic signal to be recognized according to the first sampling frequency component, the second sampling frequency component, and the aliasing region number and Nyquist region number where the electromagnetic signal to be recognized is located.

[0078] Figure 5 This is a schematic diagram of the frequency aliasing phenomenon that occurs after sampling a wideband signal provided by an embodiment of the present invention. Taking the sampling pulse signal frequency of 5 GHz as an example, representative electromagnetic signal frequencies to be recognized are selected for testing. As Figure 5 shown, between 0 and 2.5 GHz, that is, f0 is located in the baseband Nyquist region [0, frep / 2], and no mixing phenomenon will occur. The frequency of the electromagnetic signal to be recognized identified is its true frequency. Between 2.5 - 12.5 GHz, multiple mixing will occur. For example, if the detected signal frequency is 0.3 GHz, there may be 4 possible true signal frequencies at this time. Therefore, the true frequency of the electromagnetic signal to be recognized cannot be determined. If the aliasing region and Nyquist region numbers where the electromagnetic signal to be recognized is currently located can be determined, the true frequency of the electromagnetic signal to be recognized can be determined.

[0079] For example, let the frequency of the electromagnetic signal to be recognized be f s , after uniform sampling pulse signal optical sampling and preprocessing, the first sampling frequency component corresponding to the first digital signal obtained is f0, where

[0080] f0 = |nfrep - f s |, (n = 1, 2, 3...), and f0 is located in the baseband Nyquist region [0, frep / 2], where n represents the aliasing region number where the electromagnetic signal to be recognized is located, and n can also be understood as the sampling pulse harmonic number of the beat frequency between the electromagnetic signal to be recognized and the sampling pulse signal.

[0081] Generally, when the frequency f s < frep / 2 of the electromagnetic signal to be recognized, the signal frequency recognized by the wideband signal receiving and recognizing device of this embodiment will not be aliased. When the frequency f sWhen \(f_{rep} / 2\), to distinguish the aliased frequencies in the Nyquist baseband region, in this embodiment, a fixed small frequency jitter \(f\) is added to the uniform sampling pulse signal \(f_{rep}\). d Then the frequency of the obtained optical carrier signal is \(f_{rep}' = f_{rep}+f\). d \(f\). d Can be defined as positive or negative. In this embodiment, \(f\) is set d to be \( + 10MHz\), so \(f_{rep}'>f_{rep}\). The electromagnetic signal \(f\) to be recognized s The second sampling frequency component obtained by sampling with the optical carrier signal with a repetition frequency of \(f_{rep}'\) is \(f_0'\). Compared with the first sampling frequency component \(f_0\) obtained by optical sampling of the sampling pulse signal \(f_{rep}\), there is a certain offset \(f\) between \(f_0'\) and \(f_0\). shift \(f\). shift The magnitude of is equal to \(n\times f\). d That is, \(n = |f_0' - f_0| / |f|\). d |. Therefore, by calculating the frequency shift between \(f_0'\) and \(f_0\), the aliased region number \(n\) where the electromagnetic signal \(f\) to be recognized is located can be determined. In addition, the direction of the offset of \(f_0'\) relative to \(f_0\) represents the Nyquist zone \(m\) where the electromagnetic signal \(f\) to be recognized is located, \(m = 2n\) or \(m = 2n - 1\). If \(f_0'>f_0\), it is determined that the electromagnetic signal \(f\) to be recognized s is located in the Nyquist zone of \(m = 2n - 1\). At this time, \(f\) s \(=nf_{rep}-f_0\); if \(f_0'<f_0\), it is determined that the electromagnetic signal \(f\) to be recognized s is located in the Nyquist zone of \(m = 2n\). At this time, \(f\) s \(=nf_{rep}+f_0\). If the frequency jitter signal \(f\) s is negative, the method for judging the Nyquist zone is opposite to the method when \(f\) s is positive. In summary, by calculating \(f_0\), \(f_0'\), \(m\), and \(n\) of the unknown signal \(f\), the frequency information of the electromagnetic signal \(f\) to be recognized can be determined, so as to reconstruct the electromagnetic signal to be recognized. d is negative, the method for judging the Nyquist zone is opposite to the method when \(f\) d is positive. In summary, by calculating \(f_0\), \(f_0'\), \(m\), and \(n\) of the unknown signal \(f\), the frequency information of the electromagnetic signal \(f\) to be recognized can be determined, so as to reconstruct the electromagnetic signal to be recognized. s The frequency information of the electromagnetic signal \(f\) to be recognized can be determined, so as to reconstruct the electromagnetic signal to be recognized. s The frequency information of the electromagnetic signal \(f\) to be recognized can be determined, so as to reconstruct the electromagnetic signal to be recognized.

[0082] In this example, Matlab software is used for simulation. Through the following specific parameters, the processing process of the wide-band signal recognition and processing device based on microwave photon provided by the embodiment of the present invention is simulated. Among them, the mode-locked laser is set to work at a central wavelength of 1550 nm and a repetition frequency of 5 GHz, and a continuous and uniform optical pulse sequence is output. The acousto-optic frequency shifter is set with a modulation frequency of 10 MHz. After the optical pulse sequence generated by the mode-locked laser passes through the acousto-optic frequency shifter, an optical carrier signal with a non-uniform pulse sequence with a small frequency jitter of 10 MHz is output. The 3 dB bandwidth of the intensity modulator is 20 GHz, and the modulation depth is 30 dB. The amplified electromagnetic signal to be recognized received by the antenna is loaded onto the optical carrier signal, and the modulated optical signal is output through the intensity modulator, and then passes through the photodetector and the low-pass filter in sequence. The 3 dB bandwidth of the photodetector is 5 GHz, and the cut-off frequency of the low-pass filter is set to 2.5 GHz. The analog electrical signal output by the low-pass filter is then converted into a digital signal through an electronic analog-to-digital converter, and finally enters the reconstruction and recognition unit for data processing and calculation to obtain the frequency corresponding to the electromagnetic signal to be recognized.

[0083] Please refer to Figure 5 , taking the sampling pulse signal frequency of 5 GHz as an example, representative electromagnetic signal frequencies to be recognized are selected for testing. As Figure 5 shown, three groups of RF test signals are selected. The frequency of the first group of RF signals is set to 4.9 GHz, 5.1 GHz, 9.9 GHz, and 10.1 GHz, and their theoretical aliasing frequencies are all at 100 MHz. The frequency of the second group of RF signals is set to 4.7 GHz, 5.3 GHz, 9.7 GHz, and 10.3 GHz, and their theoretical aliasing frequencies are all at 300 MHz. The frequency of the third group of RF signals is set to 4.5 GHz, 5.5 GHz, 9.5 GHz, and 10.5 GHz, and their theoretical aliasing frequencies are all at 500 MHz.

[0084] Figures 6 - 11 is a schematic diagram of the frequency recognition method for three groups of RF test signals provided by the embodiment of the present invention. Figures 6 - 11 In it, the ordinate is the normalized intensity, the abscissa is the signal frequency, and the dotted line is the frequency component after down-conversion of the three groups of RF test signals when the system does not add frequency jitter f d = +10 MHz. It is tested that the aliasing frequencies of the first group of RF signal frequencies 4.9 GHz, 5.1 GHz, 9.9 GHz, and 10.1 GHz are 100 MHz, the aliasing frequencies of the second group of RF signal frequencies 4.7 GHz, 5.3 GHz, 9.7 GHz, and 10.3 GHz are 300 MHz, and the aliasing frequencies of the third group of RF signal frequencies 4.5 GHz, 5.5 GHz, 9.5 GHz, and 10.5 GHz are 500 MHz. Increasing the frequency jitter f dAfter it becomes +10 MHz, measure again. Among the first group of RF signals, the frequency components after down-conversion at 4.9 GHz and 5.1 GHz are 110 MHz and 90 MHz respectively. As Figure 5 and Figure 6 shown, according to the formula n = |f0′ - f0| / |f d |, it can be known that the aliasing region numbers n corresponding to 4.9 GHz and 5.1 GHz are both 1. According to the Nyquist region judgment condition (if f0′ > f0, then the electromagnetic signal f to be identified s is located in the Nyquist region of m = 2n - 1; if f0′ < f0, then the electromagnetic signal f to be identified s is located in the Nyquist region of m = 2n), it can be known that, as Figure 5 shown, the Nyquist region numbers m corresponding to 4.9 GHz and 5.1 GHz are 1 and 2 respectively. Among the first group of RF signals, the frequency components after down-conversion at 9.9 GHz and 10.1 GHz are 120 MHz and 80 MHz respectively. As Figure 7 shown. Similarly, it can be obtained that the aliasing region numbers n corresponding to 9.9 GHz and 10.1 GHz are both 2, and the corresponding Nyquist region numbers m are 3 and 4 respectively. Thus, it can be known that the first group of RF test signals 4.9 GHz, 5.1 GHz, 9.9 GHz, and 10.1 GHz satisfy Figure 5 the distribution rules of the aliasing region and the Nyquist region corresponding to the frequencies therein. And by comparing the frequency components after down-conversion of each RF signal before and after frequency jitter, as well as the magnitude and direction of the generated frequency offset, the frequency identification and disambiguation of the test signals 4.9 GHz, 5.1 GHz, 9.9 GHz, and 10.1 GHz with aliasing at 100 MHz can be realized. To further verify the effectiveness of the identification device provided in this embodiment, by testing the second group and the third group of RF signals in the same steps, it can be obtained that, as Figure 8 shown, among the second group of signals, the aliasing region numbers n corresponding to 4.7 GHz and 5.3 GHz are both 1, and the corresponding Nyquist region numbers m are 1 and 2 respectively. As Figure 9 shown, the aliasing region numbers n corresponding to 9.7 GHz and 10.3 GHz are both 2, and the corresponding Nyquist region numbers m are 3 and 4 respectively. As Figure 10 shown, among the third group of signals, the aliasing region numbers n corresponding to 4.5 GHz and 5.5 GHz are both 1, and the corresponding Nyquist region numbers m are 1 and 2 respectively. As Figure 11 shown, the aliasing region numbers n corresponding to 9.5 GHz and 10.5 GHz are both 2, and the corresponding Nyquist region numbers m are 3 and 4 respectively.

[0085] Figure 12 It is a schematic diagram of the identification effect of the signals in the frequency range of 2.5 GHz to 4.9 GHz by using the identification device of the embodiment of the present invention. Figure 13Schematic diagram of the recognition effect of signals in the 5.1 GHz - 7.5 GHz frequency range using the recognition device according to the embodiments of the present invention; Figure 12 and Figure 13 In, the abscissa is the recognized frequency, and the ordinate is the intensity of the signal to be recognized. Combining Figure 12 and Figure 13 , it can be seen that after the signals in the 2.5G - 7.5G frequency range are received by the device provided by the embodiments of the present invention, they can all be down-converted to a bandwidth of 0 - 2.5G, reducing the acquisition pressure of the backend digital acquisition system on wide-band signals. Then, after calculation and recognition, the true frequency of the signal to be recognized is obtained.

[0086] From the above analysis, it can be known that the wide-band signal receiving and recognizing device of this embodiment has the function of receiving and recognizing the true frequency of randomly appearing electromagnetic signals in a wide frequency band range. With the upgrade of the bandwidth and computing performance of the hardware system, for electromagnetic signals greater than 10.5 GHz or higher frequency and wideband, the device proposed in the embodiments of the present invention can also be used for frequency recognition.

[0087] Figure 14 Schematic diagram of the flow of the wide-band signal receiving and recognizing method based on microwave photon provided by the embodiments of the present invention. As Figure 14 shown, the wide-band signal receiving and recognizing method includes:

[0088] S1401. Receive the electromagnetic signal to be recognized.

[0089] Optionally, after receiving the electromagnetic signal to be recognized through the antenna, the electromagnetic signal to be recognized can also be subjected to power amplification processing.

[0090] S1402. Obtain a continuous and uniform sampling pulse signal and a non-uniform pulse signal with frequency jitter. Both of the above two signals are optical carrier signals.

[0091] Exemplarily, obtaining an optical carrier signal of a non-uniform pulse sequence with frequency jitter specifically includes: obtaining a continuous and uniform sampling pulse signal; adding a preset jitter frequency to the continuous and uniform sampling pulse signal to obtain an optical carrier signal of a non-uniform pulse sequence.

[0092] S1403. Load the electromagnetic signal to be recognized onto the uniform sampling pulse signal and perform intensity modulation to obtain a first modulated optical signal; and load the electromagnetic signal to be recognized onto the non-uniform sampling pulse signal and perform intensity modulation to obtain a second modulated optical signal.

[0093] Exemplarily, the electromagnetic signal to be recognized is respectively loaded onto the optical carrier signal to realize signal sampling of the electromagnetic signal to be recognized using signals with different sampling frequencies.

[0094] S1404. Preprocess the first modulated optical signal and the second modulated optical signal respectively to obtain corresponding first digital signal and second digital signal.

[0095] Exemplarily, preprocessing the first modulated optical signal and the second modulated optical signal respectively to obtain corresponding first digital signal and second digital signal specifically includes:

[0096] Convert the first modulated optical signal into a first electrical signal; perform low-pass filtering on the first electrical signal to obtain a second electrical signal; perform power amplification on the second electrical signal to obtain a third electrical signal; perform analog-to-digital conversion on the third electrical signal to obtain a first digital signal;

[0097] Convert the second modulated optical signal into a fourth electrical signal; perform low-pass filtering on the fourth electrical signal to obtain a fifth electrical signal; perform power amplification on the fifth electrical signal to obtain a sixth electrical signal; perform analog-to-digital conversion on the sixth electrical signal to obtain a second digital signal.

[0098] S1405. Perform recognition processing on the first digital signal and the second digital signal to obtain the frequency corresponding to the electromagnetic signal to be recognized.

[0099] Exemplarily, performing recognition processing on the first digital signal and the second digital signal to obtain the frequency corresponding to the electromagnetic signal to be recognized specifically includes:

[0100] Obtain a first sampling frequency component according to the first digital signal; obtain a second sampling frequency component according to the second digital signal; determine the aliasing region number where the electromagnetic signal to be recognized is located according to the first sampling frequency component, the second sampling frequency component and a preset jitter frequency; determine the Nyquist region number corresponding to the electromagnetic signal to be recognized according to the offset direction of the second sampling frequency component relative to the first sampling frequency component; calculate the frequency corresponding to the electromagnetic signal to be recognized according to the first sampling frequency component, the second sampling frequency component, and the aliasing region number and Nyquist region number where the electromagnetic signal to be recognized is located.

[0101] The wideband signal receiving and recognizing device described above and the wideband signal receiving and recognizing method described above can be referred to each other correspondingly, and both have the same or similar technical effects, which will not be elaborated here.

[0102] On the other hand, the present invention also provides a computer program product, which includes a computer program. The computer program can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the wideband signal receiving and identifying method based on microwave photon provided by the above-mentioned various methods. The method includes: receiving an electromagnetic signal to be identified; obtaining a continuous and uniform sampling pulse signal and a non-uniform sampling pulse signal with frequency jitter; loading the electromagnetic signal to be identified onto the uniform sampling pulse signal and performing intensity modulation to obtain a first modulated optical signal; and loading the electromagnetic signal to be identified onto the non-uniform sampling pulse signal and performing intensity modulation to obtain a second modulated optical signal; respectively preprocessing the first modulated optical signal and the second modulated optical signal to obtain corresponding first digital signal and second digital signal; performing identification processing on the first digital signal and the second digital signal to obtain the frequency corresponding to the electromagnetic signal to be identified.

[0103] In another aspect, the present invention also provides a non-transitory computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, it is configured to execute the wideband signal receiving and identifying method based on microwave photon provided by the above-mentioned various methods. The method includes: receiving an electromagnetic signal to be identified; obtaining a continuous and uniform sampling pulse signal and a non-uniform sampling pulse signal with frequency jitter; loading the electromagnetic signal to be identified onto the uniform sampling pulse signal and performing intensity modulation to obtain a first modulated optical signal; and loading the electromagnetic signal to be identified onto the non-uniform sampling pulse signal and performing intensity modulation to obtain a second modulated optical signal; respectively preprocessing the first modulated optical signal and the second modulated optical signal to obtain corresponding first digital signal and second digital signal; performing identification processing on the first digital signal and the second digital signal to obtain the frequency corresponding to the electromagnetic signal to be identified.

[0104] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separated. The components shown as units may or may not be physical units, that is, they may be located in one place or distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. Those of ordinary skill in the art can understand and implement it without creative work.

[0105] Through the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on such an understanding, the essence of the above technical solution, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0106] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. These modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A wide-band signal receiving and identifying device based on microwave photonics, characterized in that, Including: A signal generating unit, a signal receiving unit, a signal modulating unit, a signal processing unit, and a reconstruction and recognition unit; The signal receiving unit is configured to receive the electromagnetic signal to be recognized; The signal generating unit is configured to generate a continuous and uniform sampling pulse signal and a non-uniform sampling pulse signal with frequency jitter; The signal modulating unit is configured to load the electromagnetic signal to be recognized onto the uniform sampling pulse signal and perform intensity modulation to obtain a first modulated optical signal; and load the electromagnetic signal to be recognized onto the non-uniform sampling pulse signal with frequency jitter and perform intensity modulation to obtain a second modulated optical signal; The signal processing unit is configured to perform preprocessing on the first modulated optical signal and the second modulated optical signal respectively to obtain corresponding first digital signal and second digital signal; The reconstruction and recognition unit is configured to perform recognition processing on the first digital signal and the second digital signal to obtain the frequency corresponding to the electromagnetic signal to be recognized; The reconstruction and recognition unit is specifically configured to: Obtain a first sampling frequency component according to the first digital signal; Obtain a second sampling frequency component according to the second digital signal; Determine the aliasing region number where the electromagnetic signal to be recognized is located according to the first sampling frequency component, the second sampling frequency component, and a preset jitter frequency; Determine the Nyquist region number corresponding to the electromagnetic signal to be recognized according to the offset amount of the second sampling frequency component relative to the first sampling frequency component; Calculate the frequency corresponding to the electromagnetic signal to be recognized according to the first sampling frequency component, the second sampling frequency component, and the aliasing region number and Nyquist region number where the electromagnetic signal to be recognized is located.

2. The wide-band signal receiving and identifying device based on microwave photon according to claim 1, characterized in that, The signal generating unit includes a mode-locked laser and an acousto-optic frequency shifter; The mode-locked laser is configured to generate the continuous and uniform sampling pulse signal; the acousto-optic frequency shifter is configured to add a preset jitter frequency to the sampling pulse signal to obtain the non-uniform sampling pulse signal.

3. The broadband signal receiving and identifying device based on microwave photon according to claim 1, characterized in that The signal receiving unit includes an antenna and a first signal amplifier; The antenna is configured to receive the electromagnetic signal to be recognized; the first signal amplifier is configured to perform power amplification processing on the electromagnetic signal to be recognized.

4. The wideband signal receiving and identifying device based on microwave photon according to claim 2, wherein The signal processing unit includes a photodetector, a low-pass filter, a second signal amplifier, and an analog-to-digital converter; The photodetector is configured to detect the first modulated optical signal and convert it into a first electrical signal; the low-pass filter is configured to perform low-pass filtering processing on the first electrical signal to obtain a second electrical signal; the second signal amplifier is configured to perform power amplification processing on the second electrical signal to obtain a third electrical signal; the analog-to-digital converter is configured to perform analog-to-digital conversion processing on the third electrical signal to obtain the first digital signal; The photodetector is further configured to detect the second modulated optical signal and convert it into a fourth electrical signal; the low-pass filter is further configured to perform low-pass filtering on the fourth electrical signal to obtain a fifth electrical signal; the second signal amplifier is further configured to perform power amplification on the fifth electrical signal to obtain a sixth electrical signal; and the analog-to-digital converter is configured to perform analog-to-digital conversion on the sixth electrical signal to obtain the second digital signal.

5. A wide-band signal receiving and identifying method based on microwave photonics, characterized in that, including: receiving an electromagnetic signal to be identified; acquiring a continuous and uniform sampling pulse signal and a non-uniform pulse signal with frequency jitter; loading the electromagnetic signal to be identified onto the uniform sampling pulse signal and performing intensity modulation to obtain a first modulated optical signal; and loading the electromagnetic signal to be identified onto the non-uniform pulse signal and performing intensity modulation to obtain a second modulated optical signal; performing preprocessing on the first modulated optical signal and the second modulated optical signal respectively to obtain corresponding first and second digital signals; performing identification processing on the first digital signal and the second digital signal to obtain the frequency corresponding to the electromagnetic signal to be identified; wherein, the performing identification processing on the first digital signal and the second digital signal to obtain the frequency corresponding to the electromagnetic signal to be identified includes: obtaining a first sampling frequency component according to the first digital signal; obtaining a second sampling frequency component according to the second digital signal; determining the aliasing region number where the electromagnetic signal to be identified is located according to the first sampling frequency component, the second sampling frequency component and a preset jitter frequency; determining the Nyquist region number corresponding to the electromagnetic signal to be identified according to the offset of the second sampling frequency component relative to the first sampling frequency component; calculating the frequency corresponding to the electromagnetic signal to be identified according to the first sampling frequency component, the second sampling frequency component, and the aliasing region number and Nyquist region number where the electromagnetic signal to be identified is located.

6. The method for receiving and identifying wide-band signals based on microwave photon according to claim 5, wherein, The performing preprocessing on the first modulated optical signal and the second modulated optical signal respectively to obtain corresponding first and second digital signals includes: converting the first modulated optical signal into a first electrical signal; performing low-pass filtering on the first electrical signal to obtain a second electrical signal; performing power amplification on the second electrical signal to obtain a third electrical signal; and performing analog-to-digital conversion on the third electrical signal to obtain the first digital signal; converting the second modulated optical signal into a fourth electrical signal; performing low-pass filtering on the fourth electrical signal to obtain a fifth electrical signal; performing power amplification on the fifth electrical signal to obtain a sixth electrical signal; and performing analog-to-digital conversion on the sixth electrical signal to obtain the second digital signal.

7. The wide-band signal receiving and identifying method based on microwave photon according to claim 5, characterized in that, The acquiring an optical carrier signal with a non-uniform pulse sequence having frequency jitter includes: acquiring a continuous and uniform sampling pulse signal; adding a preset jitter frequency to the continuous and uniform sampling pulse signal to obtain the optical carrier signal.

8. A computer program product comprising a computer program, characterized in that, When the computer program is executed by a processor, it implements the broadband signal receiving and identifying method based on microwave photon as described in any one of claims 5 to 7.

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