A distributed microwave synchronization system and method

Abstract

The present invention relates to the field of microwave technology, and provides a distributed microwave synchronization system, wherein the distributed microwave synchronization system utilizes dual acousto-optic frequency shifters at a transmitting end and a receiving end, and mixes frequency-shifted transmission light with frequency-shifted reflected light through an optical combiner to generate a beat frequency microwave signal, wherein the frequency-shifted reflected light is generated by the second acousto-optic frequency shifter by frequency-shifting the reflected light and is returned to the transmitting end, wherein the high-speed voltage comparator generates a beat frequency digital signal based on the beat frequency microwave signal, and the digital chip obtains the phase information of the beat frequency microwave signal based on the beat frequency digital signal; the transmitting end or the receiving end performs phase synchronization of the microwave signal based on the phase information. The present invention can replace the wavelength division multiplexing scheme using two wavelength lasers, and in a single wavelength laser system, a simpler and lower-cost method is used to eliminate the influence of Rayleigh scattering.

Description

Technical Field

[0001] The present invention relates to the field of microwave technology, and in particular to a distributed microwave synchronization system and method. Background Art

[0002] The distributed microwave synchronization system is used to transmit the microwave reference signal generated by a transmitter to multiple receivers at distances ranging from tens of meters to tens of kilometers, or even farther, and requires that the microwave signal output by the receiver be phase-locked with the microwave reference signal.

[0003] There are many ways to implement a microwave synchronization system. One of them is to modulate (amplitude modulate) the microwave reference signal onto a continuous laser, transmit it to each receiving end through an optical fiber, and use a photodiode at the receiving end to recover the microwave signal. Because the length of the transmission optical fiber changes with the ambient temperature, the microwave signal recovered by the photodiode at the receiving end is not phase-locked with the microwave reference signal. The change in the length of the transmission optical fiber can be converted into a beat frequency optical signal through a Michelson or Mach-Zehnder fiber interferometer structure, and then converted into a beat frequency microwave signal by a photodiode. The control system measures the beat frequency microwave signal, calculates the change in the optical fiber length, and then compensates for the optical path length, or compensates for the phase of the microwave signal recovered by the photodiode at the receiving end, so that the microwave signal output by the receiving end is phase-locked with the microwave reference signal. The above scheme only uses an interferometer to monitor the change in optical fiber length in real time. Although the measurement accuracy is high, the disadvantage is that it cannot monitor the change in the absolute length of the optical fiber.

[0004] Another method is to use an interferometer in combination with microwave phase detection (clock phase detection) and other technical solutions to realize a system solution that can monitor the change of the absolute length of the optical fiber. However, it is necessary to use laser wavelength division multiplexing technology, that is, two wavelengths of laser are used in the system at the same time, one wavelength of laser is used to implement the interferometer solution, and the other wavelength of laser is used to implement the microwave phase detection solution to avoid Rayleigh scattering affecting the accuracy of microwave phase detection. Although this method improves the measurement accuracy of the microwave phase detection solution, the use of two wavelength laser systems greatly increases the system complexity and cost. Summary of the invention

[0005] The present invention provides a distributed microwave synchronization system, which includes a transmitting end and a receiving end. The transmitting end includes a first acousto-optic frequency shifter, a light combiner, a high-speed voltage comparator and a digital chip. The receiving end includes a second acousto-optic frequency shifter. The first acousto-optic frequency shifter is used to shift the frequency of an original frequency transmission light to generate a frequency-shifted transmission light. The frequency-shifted transmission light is mixed with a frequency-shifted reflected light by the light combiner to generate a beat frequency microwave signal. The frequency-shifted reflected light is generated by the second acousto-optic frequency shifter by shifting the frequency of the reflected light and is returned to the transmitting end. The high-speed voltage comparator generates a beat frequency digital signal based on the beat frequency microwave signal. The digital chip obtains phase information of the beat frequency microwave signal based on the beat frequency digital signal. The transmitting end or the receiving end performs phase synchronization of the microwave signal based on the phase information.

[0006] Optionally, the first acousto-optic frequency shifter constitutes a primary frequency shift structure.

[0007] Optionally, the transmitting end includes a first power divider and a second power divider, the first power divider is connected to the first acousto-optic frequency shifter and is used to divide the frequency-shifted transmission light into multiple paths, and the second power divider is used to divide the original frequency transmission light into multiple paths.

[0008] Optionally, the transmitting end further includes a second circulator and a second Faraday rotator, and the second circulator, the first acousto-optic frequency shifter, and the second Faraday rotator are connected in sequence to form a secondary frequency shift structure.

[0009] Optionally, the transmitting end includes a first power divider and a second power divider, the first power divider is connected to the second circulator and is used to divide the frequency-shifted transmission light into multiple paths, and the second power divider is used to divide the original frequency transmission light into multiple paths.

[0010] Optionally, the transmitting end includes a first circulator, which is used to send the original frequency transmission light to the transmission optical fiber, and output the received frequency-shifted reflected light returned from the receiving end to the light combiner.

[0011] Optionally, the receiving end includes a first Faraday rotator connected to the second acousto-optic frequency shifter, which is used to rotate the polarization state of the microwave signal after the primary frequency shift by 90 degrees and then input it into the second acousto-optic frequency shifter for secondary frequency shift.

[0012] Optionally, the first acousto-optic frequency shifter and the second acousto-optic frequency shifter have different operating frequencies to reduce the frequency of the beat microwave signal.

[0013] Optionally, the clock frequency of the digital chip is greater than or equal to 4 times the frequency of the beat frequency microwave signal.

[0014] The present invention also provides a distributed microwave synchronization method, the method comprising:

[0015] The original frequency transmission light is frequency-shifted to generate frequency-shifted transmission light;

[0016] receiving the returned frequency-shifted reflected light;

[0017] Mixing the frequency-shifted transmitted light with the frequency-shifted reflected light to generate a beat frequency microwave signal;

[0018] generating a beat frequency digital signal based on the beat frequency microwave signal;

[0019] Acquiring phase information of a beat frequency microwave signal based on the beat frequency digital signal;

[0020] Phase synchronization of the microwave signal is performed based on the phase information.

[0021] The present invention provides an electronic device, comprising a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor implements the above-mentioned distributed microwave synchronization method when executing the program.

[0022] The present invention provides a non-transitory computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, the distributed microwave synchronization method described above is implemented.

[0023] The distributed microwave synchronization system and the distributed microwave synchronization method provided by the present invention add an acousto-optic frequency shifter at the transmitting end, and the laser generates frequency-shifted transmission light after one or two frequency shifts, and then mixes with the frequency-shifted reflected laser to generate a mixed optical signal, thereby eliminating the Rayleigh scattering effect. The present invention can replace the wavelength division multiplexing solution, and in a single wavelength laser system, use a simpler and lower-cost method to eliminate the influence of Rayleigh scattering, and can solve the problems of high cost, complex algorithm, and small number of signals that can be monitored by a single FPGA chip when using a high-speed ADC chip to measure beat frequency microwave signals. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 It is a schematic diagram of the optical path of the distributed microwave synchronization system provided by the present invention;

[0026] Figure 2 It is a schematic diagram of a single-channel primary frequency shift structure in a distributed microwave synchronization system provided by the present invention;

[0027] Figure 3 It is a schematic diagram of a single-channel secondary frequency shift structure in a distributed microwave synchronization system provided by the present invention;

[0028] Figure 4 It is a schematic diagram of a multi-channel primary frequency shift structure in a distributed microwave synchronization system provided by the present invention;

[0029] Figure 5 It is a schematic diagram of a multi-channel secondary frequency shift structure in a distributed microwave synchronization system provided by the present invention;

[0030] Figure 6 It is a local structural diagram for obtaining phase signal of mixed microwave signal;

[0031] Figure 7 It is a flow chart of a distributed microwave synchronization method provided by the present invention;

[0032] Figure 8 It is a structural schematic diagram of the electronic device provided by the present invention. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] The purpose of this application is to replace the wavelength division multiplexing solution, use a simpler and lower-cost method to eliminate the influence of Rayleigh scattering in a single wavelength laser system, and realize the combination of the two monitoring methods of interferometer and microwave phase detection in a microwave synchronization system. At the same time, it can solve the problems of high cost, complex algorithm, and small number of signals that can be monitored by a single FPGA chip when using a high-speed ADC chip to measure beat frequency microwave signals.

[0035] The present invention provides a distributed microwave synchronization system, such as Figure 1As shown, the distributed microwave synchronization system includes a transmitting end and a receiving end, the transmitting end includes a first acousto-optic frequency shifter 11, a light combiner 12, a high-speed voltage comparator 13 and a digital chip 14, the receiving end includes a second acousto-optic frequency shifter 21, the first acousto-optic frequency shifter 11 is used to shift the frequency of the original frequency transmission light to generate a frequency-shifted transmission light, the frequency-shifted transmission light is mixed with the frequency-shifted reflected light through the light combiner 12 to generate a beat frequency microwave signal, the frequency-shifted reflected light is generated by the second acousto-optic frequency shifter 21 by shifting the frequency of the reflected light and is returned to the transmitting end, the high-speed voltage comparator 13 generates a beat frequency digital signal based on the beat frequency microwave signal, and the digital chip 14 obtains the phase information of the beat frequency microwave signal based on the beat frequency digital signal; the transmitting end or the receiving end performs phase synchronization of the microwave signal based on the phase information.

[0036] In a single-wavelength laser system, this solution uses a dual acousto-optic frequency shifter (one at the transmitting end and one at the receiving end) system structure to eliminate the influence of Rayleigh scattering and realize the combination of the two monitoring methods of interferometer and microwave phase detection in the synchronization system. By adding an AOM-1 at the transmitting end, the original frequency transmission light is frequency-shifted once or twice to generate frequency-shifted transmission light, and the frequency of the frequency-shifted transmission light is inconsistent with the frequency of the frequency-shifted reflected light. The frequency-shifted transmission light and the frequency-shifted reflected light are mixed to generate a beat frequency signal, and the frequency of the beat frequency signal is the frequency difference between the frequency-shifted transmission light and the frequency-shifted reflected light. Since the frequency of the Rayleigh scattered light is still consistent with the original frequency transmission light, but inconsistent with the frequencies of the frequency-shifted transmission light and the frequency-shifted reflected light, the Rayleigh scattering effect will no longer occur after mixing.

[0037] By using a dual acousto-optic frequency shifter architecture and selecting different driving frequencies of AOM-1 and AOM-2, a beat frequency microwave signal with a lower frequency can be obtained. In this way, the beat frequency microwave signal can be first converted into a beat frequency digital signal (high / low level signal) through a high-speed voltage comparator (zero-crossing comparison), and then the beat frequency digital signal is connected to the FPGA chip (each beat frequency digital signal only needs to occupy one FPGA chip pin), and the rising edge and falling edge of the beat frequency digital signal are judged by the FPGA, and counted. The clock frequency of the FPGA chip needs to be greater than or equal to 4 times the frequency of the beat frequency microwave signal. Because the rising edge or falling edge of each beat frequency digital signal represents a 180-degree phase change of the beat frequency microwave signal, the count values ​​of the rising edge and the falling edge can represent the phase change, thereby realizing the monitoring of the phase change of the beat frequency signal. FPGA can also be replaced with other types of digital chips to realize the counter function.

[0038] The optical combiner 12 is a device that can combine light wave energy. It combines the light energy transmitted in two optical fibers into one optical fiber. The optical combiner is a passive device, also known as an optical splitter. It does not require external energy. As long as there is input light, it can achieve the mixing and superposition of the two optical energies.

[0039] like Figure 2 As shown, the first acousto-optic frequency shifter constitutes a single-channel single-frequency shift structure. Specifically, the transmitting end includes a laser 100, an amplitude modulator 102, a first acousto-optic frequency shifter 11, a first circulator 103, and a photodiode 104, wherein the laser 100 emits a laser, and the amplitude modulator 102 performs amplitude modulation on the laser to generate a modulated laser signal. The modulated laser signal is sent to the transmission optical fiber through the channel of port 1 input-port 2 output of the first circulator 103, and is frequency-shifted once through the first acousto-optic frequency shifter 11 to generate a frequency-shifted transmission light. The frequency-shifted reflected light received by the transmission optical fiber is superimposed with the frequency-shifted transmission light through the channel of port 2 input-port 3 output of the first circulator 103, and the superimposed laser signal generates a beat frequency signal through the photodiode 104.

[0040] like Figure 3 As shown, the first acousto-optic frequency shifter forms a single-channel secondary frequency shift structure. Specifically, the transmitting end includes a laser 100, an amplitude modulator 102, a second circulator 301, a second Faraday rotator 302, a first acousto-optic frequency shifter 11, a first circulator 103, and a photodiode 104, wherein the laser 130 emits a laser, and the amplitude modulator 102 performs amplitude modulation on the laser to generate a modulated laser signal. The modulated laser signal is sent to the transmission optical fiber through the channel from port 1-port input to port 2-port output of the first circulator 103, and is output to the first acousto-optic frequency shifter 11 through the channel from port 1-port input to port 2-port output of the second circulator 301 for the first frequency shift. The laser signal after the first frequency shift is polarized by 90 degrees through the Faraday rotator 302, and then returns to the first acousto-optic frequency shifter 11 for the second frequency shift. After the second frequency shift, frequency-shifted transmission light is generated through the channel from port 2-port input to port 3-port output of the second circulator 301. The frequency-shifted reflected light received by the transmission optical fiber is superimposed with the frequency-shifted transmission light through the channel from port 2-port input to port 3-port output of the first circulator, and the superimposed laser signal generates a beat frequency signal through a photodiode.

[0041] The above are two single-channel schematic diagrams. In actual applications, a power divider can be used to divide the laser into multiple channels. Even for multi-channel solutions, only one AOM-1 is needed at the transmitter, but each receiver needs an AOM-2. For specific circuit diagrams, see Figure 4 and Figure 5 , Figure 4 The structure shown is a multi-channel single frequency shift structure. Figure 5 The structure shown is a multi-channel secondary frequency shift structure.

[0042] Figure 4 In the embodiment, the transmitting end includes a first power divider 401 and a second power divider 402. The first power divider 401 is connected to the first acousto-optic frequency shifter and is used to divide the frequency-shifted transmission light into multiple paths. The second power divider 402 is used to divide the original frequency transmission light into multiple paths.

[0043] Figure 5 In the figure, the transmitting end includes a first power divider 401 and a second power divider 402. The first power divider 401 is connected to port 3 of the second circulator and is used to divide the frequency-shifted transmitted light into multiple paths. The second power divider 402 is used to divide the original frequency transmitted light into multiple paths.

[0044] When constructing the optical path, Figures 2 to 5 The circulator in can also be replaced by a power divider.

[0045] It can be seen from the above specific implementation that no matter in a single-channel solution or a multi-channel solution, at the transmitting end, the second circulator, the first acousto-optic frequency shifter, and the second Faraday rotator are connected in sequence to realize a secondary frequency shift structure.

[0046] In the multi-channel solution, the transmitting end includes a first power divider and a second power divider. The frequency-shifted transmission light is divided into multiple paths by the first power divider, and the original frequency transmission light is divided into multiple paths by the second power divider.

[0047] In the present invention, the transmitting end includes a first circulator, which is used to send the original frequency transmission light to the transmission optical fiber and output the received frequency-shifted reflected light returned from the receiving end to the light combiner.

[0048] In the present invention, the receiving end includes a first Faraday rotator 22 connected to the second acousto-optic frequency shifter, which is used to rotate the polarization state of the microwave signal after the first frequency shift by 90 degrees and then input it back to the second acousto-optic frequency shifter for secondary frequency shift. This solution only requires one path, the solution is simple and easy to implement. The receiving end does not necessarily have to perform secondary frequency shift, and the reflected light output by the second acousto-optic frequency shifter after the first frequency shift can also be returned to the transmitting end through the transmission optical fiber.

[0049] The first acousto-optic frequency shifter and the second acousto-optic frequency shifter have different operating frequencies, which can reduce the frequency of the beat frequency microwave signal. The beat frequency microwave signal is a sinusoidal analog voltage signal with a fixed frequency, and the positive and negative polarities of its voltage change alternately according to the signal frequency. The function of the voltage comparator is to give a reference voltage as a comparison threshold. If the input signal voltage is higher than the threshold, the voltage comparator outputs a high level (or a low level). If the input signal voltage is lower than the threshold, the voltage comparator outputs a low level (or a high level). If the beat frequency microwave signal is used as the input signal of the voltage comparator, and the 0V voltage is used as the comparison threshold (zero-crossing comparison), then the output signal of the voltage comparator is a digital signal with a duty cycle of 50% with alternating high / low levels according to the input signal frequency. In this way, the beat frequency microwave signal can be converted into a beat frequency digital signal, see Figure 6 .

[0050] The common AOM operating frequency range is currently 40MHz to 200MHz. In the existing single AOM synchronous system structure, even if the lowest AOM operating frequency of 40MHz is selected, the laser frequency is changed by 80MHz because the laser passes through the AOM twice when it reaches the receiving end and is reflected from the receiving end back to the transmitting end. That is, the frequency of the beat frequency microwave signal is 80MHz. When the current FPGA is in use, the clock frequency is generally lower than 200MHz. At the same time, the algorithm for FPGA to judge the rising and falling edges of external digital signals usually uses multi-level registers, that is, it takes multiple clock cycles to accurately judge a rising edge or falling edge, so the FPGA clock frequency should be greater than or equal to 4 times the signal frequency.

[0051] In this way, even if the lowest frequency of the beat frequency digital signal is 80MHz, it is difficult to accurately judge the rising edge and the falling edge using the FPGA clock frequency of 200MHz. However, by adopting the dual AOM synchronous system structure proposed by the present invention (i.e., both the transmitting end and the receiving end are provided with AOM for frequency shifting), by selecting different operating frequencies of AOM-1 and AOM-2, a lower frequency difference can be achieved, that is, a beat frequency signal with a lower frequency is generated. For example, the driving frequency of AOM-1 is 100MHz (one frequency shift), and the driving frequency of AOM-2 is 55MHz (two frequency shifts), then the obtained beat frequency optical signal frequency is 10MHz, so that the FPGA clock frequency can easily reach 4 times or more of the beat frequency digital signal frequency. Whether the transmitting end and the receiving end undergo one frequency shift or two frequency shifts depends on the operating frequencies of AOM-1 and AOM-2 and the target frequency of the beat frequency signal to be obtained. The one-time frequency shift structure or the two-time frequency shift structure can be selected according to actual requirements.

[0052] The present invention also provides a distributed microwave synchronization method, such as Figure 7 As shown, the method includes:

[0053] S1. Shift the original frequency transmission light to generate frequency-shifted transmission light;

[0054] S2. Receive the returned frequency-shifted reflected light;

[0055] S3. The frequency-shifted transmitted light and the frequency-shifted reflected light are mixed to generate a beat frequency microwave signal;

[0056] S4. Generating a beat frequency digital signal based on the beat frequency microwave signal;

[0057] S5. Obtaining phase information of the beat frequency microwave signal based on the beat frequency digital signal;

[0058] S6. Perform phase synchronization of the microwave signal based on the phase information.

[0059] The above method generates a mixed light signal by frequency shifting the laser once or twice to generate a frequency shifted transmission light, and then mixes it with the frequency shifted reflected laser, thereby eliminating the Rayleigh scattering effect.

[0060] The distributed microwave synchronization system and the distributed microwave synchronization method provided by the present invention add an acousto-optic frequency shifter at the transmitting end, and the laser generates frequency-shifted transmission light after one or two frequency shifts, and then mixes with the frequency-shifted reflected laser to generate a mixed optical signal, thereby eliminating the Rayleigh scattering effect. The present invention can replace the wavelength division multiplexing solution, and in a single wavelength laser system, use a simpler and lower-cost method to eliminate the influence of Rayleigh scattering, and can solve the problems of high cost, complex algorithm, and small number of signals that can be monitored by a single FPGA chip when using a high-speed ADC chip to measure beat frequency microwave signals.

[0061] In the above step S6, there are two ways to perform phase synchronization of the microwave signal based on the phase information. The first means is an optical path compensation method, and the second means is a microwave phase compensation method.

[0062] The optical path compensation method is to directly compensate for the change in the length of the transmission optical fiber by changing the optical path length. There are generally two methods. The first method uses a fiber stretcher (Piezo-stretcher) to use the deformation of piezoelectric ceramics to cause elastic deformation of the optical fiber, thereby changing the length of the optical fiber. This method is used in systems with a small range of transmission fiber length changes and high control accuracy requirements. The second method disconnects the transmission optical fiber and allows the laser to be transmitted through a certain distance in space before entering the optical fiber for long-distance transmission. The distance between the two sections of optical fiber is adjusted by a motor, that is, the transmission length of the spatial light is adjusted, thereby changing the total optical transmission distance. This method is used in systems with a large range of transmission fiber length changes and low control accuracy requirements.

[0063] For systems with a large range of transmission optical fiber length variations and high control accuracy requirements, the above two methods will be combined, with the motor performing coarse adjustments and the optical fiber stretcher performing fine adjustments.

[0064] The microwave phase compensation method is to compensate the microwave phase at the receiving end. That is, the microwave receiving signal generated by the photodiode at the receiving end is not phase-locked with the microwave reference signal at the transmitting end because it is affected by the change in optical fiber length. The microwave receiving signal is passed through a microwave phase shifter to change the microwave phase so that it is phase-locked with the microwave reference signal. Microwave phase shifters can be implemented in many ways, such as voltage-controlled phase shifters or microwave low-level systems.

[0065] The synchronous phase locking of the microwave signal can be achieved based on the phase information obtained in step S5 through the above various different methods.

[0066] The present invention provides an electronic device, such as Figure 8 As shown, the electronic device may include: a processor 810, a communication interface 820, a memory 830 and a communication bus 840, wherein the processor 810, the communication interface 820 and the memory 830 communicate with each other through the communication bus 840. The processor 810 may call the logic instructions in the memory 830, and the processor 810 implements the distributed microwave synchronization method as described above when executing the logic instructions.

[0067] In addition, the logic instructions in the above-mentioned memory 830 can be implemented in the form of a software functional unit and can be stored in a computer-readable storage medium when it is sold or used as an independent product. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0068] 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 above-mentioned distributed microwave synchronization method.

[0069] On the other hand, the present invention further provides a non-transitory computer-readable storage medium having a computer program stored thereon, which is implemented to perform the above-mentioned distributed microwave synchronization method when executed by a processor.

[0070] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative labor.

[0071] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method 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 this understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for 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.

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A distributed microwave synchronization system, comprising a transmitting end and a receiving end, characterized in that: The transmitting end includes a first acousto-optic frequency shifter, a light combiner, a high-speed voltage comparator and a digital chip, the receiving end includes a second acousto-optic frequency shifter, the first acousto-optic frequency shifter is used to shift the frequency of the original frequency transmission light to generate a frequency-shifted transmission light, the frequency-shifted transmission light is mixed with the frequency-shifted reflected light through the light combiner to generate a beat frequency microwave signal, the frequency-shifted reflected light is generated by the second acousto-optic frequency shifter by shifting the frequency of the reflected light and is returned to the transmitting end, the high-speed voltage comparator generates a beat frequency digital signal based on the beat frequency microwave signal, and the digital chip obtains phase information of the beat frequency microwave signal based on the beat frequency digital signal; the transmitting end or the receiving end performs phase synchronization of the microwave signal based on the phase information; The transmitting end comprises a first circulator, which is used to transmit the original frequency transmission light to the transmission optical fiber, and output the received frequency-shifted reflected light returned from the receiving end to the optical combiner.

2. The distributed microwave synchronization system according to claim 1, characterized in that: The first acousto-optic frequency shifter forms a primary frequency shift structure.

3. The distributed microwave synchronization system according to claim 2, characterized in that: The transmitting end includes a first power divider and a second power divider. The first power divider is connected to the first acousto-optic frequency shifter and is used to divide the frequency-shifted transmission light into multiple paths. The second power divider is used to divide the original frequency transmission light into multiple paths.

4. The distributed microwave synchronization system according to claim 1, characterized in that: The transmitting end further includes a second circulator and a second Faraday rotator. The second circulator, the first acousto-optic frequency shifter and the second Faraday rotator are connected in sequence to form a secondary frequency shift structure.

5. The distributed microwave synchronization system according to claim 4, characterized in that: The transmitting end includes a first power divider and a second power divider. The first power divider is connected to the second circulator and is used to divide the frequency-shifted transmission light into multiple paths. The second power divider is used to divide the original frequency transmission light into multiple paths.

6. The distributed microwave synchronization system according to claim 1, characterized in that: The receiving end comprises a first Faraday rotator connected to the second acousto-optic frequency shifter, which is used to rotate the polarization state of the microwave signal after the primary frequency shift by 90 degrees and then input it into the second acousto-optic frequency shifter for secondary frequency shift.

7. The distributed microwave synchronization system according to claim 1, characterized in that: The first acousto-optic frequency shifter and the second acousto-optic frequency shifter have different operating frequencies so as to reduce the frequency of the beat frequency microwave signal.

8. The distributed microwave synchronization system according to claim 1, characterized in that: The clock frequency of the digital chip is greater than or equal to 4 times the frequency of the beat frequency microwave signal.

9. A distributed microwave synchronization method, characterized in that: For use in a distributed microwave synchronization system as claimed in any one of claims 1 to 8, the method comprising: The original frequency transmission light is frequency-shifted to generate frequency-shifted transmission light; receiving the returned frequency-shifted reflected light; Mixing the frequency-shifted transmitted light with the frequency-shifted reflected light to generate a beat frequency microwave signal; generating a beat frequency digital signal based on the beat frequency microwave signal; Acquiring phase information of a beat frequency microwave signal based on the beat frequency digital signal; Phase synchronization of the microwave signal is performed based on the phase information.

10. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the program, the distributed microwave synchronization method as claimed in claim 9 is implemented.

11. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the distributed microwave synchronization method according to claim 9 is implemented.

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