A remote closed-loop wireless phase coherent system based on digital domain signal processing

Abstract

This invention discloses a long-range closed-loop wireless phase-coherent system based on digital domain signal processing. The master transceiver's integrated circuit chip is sequentially connected to a first RF transceiver chip and a first patch antenna, and a fourth patch antenna is sequentially connected to a second bandpass filter and the integrated circuit chip. The slave transceiver includes a second patch antenna, a second RF transceiver chip, a first bandpass filter, a third RF transceiver chip, and a third patch antenna, all sequentially connected. The first and second patch antennas are wirelessly connected, as are the third and fourth patch antennas. This invention introduces digital signal processing methods to achieve distance-independent phase coherence between the master and slave transceivers, simplifying the structure of phase-locked loop filters and other components in the circuit. It possesses strong robustness and avoids additional delay interference caused by harmonics and analog circuits. This invention can be applied to a wide range of fields, including beamforming, phased arrays, and bistatic radar systems.

Description

Technical Field

[0001] This invention relates to a phase coherence system, specifically a remote closed-loop wireless phase coherence system based on digital domain signal processing. Background Technology

[0002] In recent years, multistatic synthetic aperture radar (SAR) systems have sparked a research boom in the field of microwave engineering. A multistatic SAR system consists of two or more spatially independent monostatic radars. Compared to monostatic radar systems, multistatic SAR systems exhibit many superior performance characteristics, such as simultaneous multi-view detection, a considerably larger synthetic aperture, flexible and economical system construction, and forward imaging. However, to realize these advantages, multistatic radar systems, compared to monostatic radars, require strict phase coherence between the long-range systems. Achieving long-range phase coherence between these monostatic radars wirelessly is one of the most challenging technical problems that must be solved before the practical application of multistatic radar systems. The basic idea of ​​long-range closed-loop phase coherence is to compensate for the phase through closed-loop feedback operations, canceling the phase delay caused by the transmission distance between the transmitter and receiver, so that the output signal at the far end always maintains phase coherence with the initial signal at the local end at any transmission distance.

[0003] Traditional long-range closed-loop wireless phase-coherent systems employ analog systems. To avoid simultaneous transmission and reception at the same frequency, the initial signal is down-converted before transmission, and an additional reference signal is generated. Both signals are then transmitted together to the slave transceiver. During transmission, multipath effects are ignored, and the two signals accumulate phase linearly with the transmission time. At the slave transceiver, the two received signals are mixed to obtain the output signal, which is then transmitted back to the master transceiver along the same transmission path to participate in the feedback calculation. The feedback calculation mainly includes a frequency divider module and several mixers. However, traditional analog-domain long-range closed-loop wireless phase-coherent systems have several problems: 1. The frequency divider module in the feedback loop uses a phase-locked loop structure, introducing additional circuit delay uncertainties that affect the phase of the output signal; 2. The use of nonlinear circuit structures such as mixers in the analog system introduces interference signals such as second harmonics; 3. Analog circuits are more susceptible to interference in wireless communication, resulting in a low signal-to-noise ratio. Summary of the Invention

[0004] To address the problems existing in the background technology, the present invention provides a remote closed-loop wireless phase coherence system based on digital domain signal processing. The present invention introduces a digital signal processing method to realize loop operation in the remote closed-loop wireless phase coherence system, and realizes phase coherence of the output signals of the master and slave transceivers independent of distance.

[0005] The technical solution adopted in this invention is:

[0006] The remote closed-loop wireless phase coherent system of the present invention includes a master transceiver and a slave transceiver, which are wirelessly connected. The master transceiver includes an integrated circuit chip, a first radio frequency transceiver chip, a first patch antenna, a fourth patch antenna, a fourth radio frequency transceiver chip, and a second bandpass filter. The integrated circuit chip is sequentially connected to the first radio frequency transceiver chip and the first patch antenna, and the fourth patch antenna is sequentially connected to the second bandpass filter and the integrated circuit chip. The slave transceiver includes a second patch antenna, a second radio frequency transceiver chip, a first bandpass filter, a third radio frequency transceiver chip, and a third patch antenna, which are sequentially connected. The first patch antenna and the second patch antenna are wirelessly connected, and the third patch antenna and the fourth patch antenna are wirelessly connected.

[0007] The integrated circuit chip includes a first reference signal frequency generation module, an initial signal frequency generation module, a second reference signal frequency generation module, a first down-conversion digital mixer module, a first up-conversion digital mixer module, a second down-conversion digital mixer module, a divide-by-two module, and a second up-conversion digital mixer module. The first reference signal frequency generation module, the initial signal frequency generation module, and the second reference signal frequency generation module generate three sinusoidal signals of different frequencies. The first sinusoidal signal output from the first reference signal frequency generation module is output to the first up-conversion digital mixer module. The initial signal frequency generation module outputs its second sinusoidal signal to the first down-conversion digital mixer module. The reference signal frequency generation module outputs the third sine wave signal to the second up-conversion digital mixer module. The frequency divider module outputs a disturbance signal to the second up-conversion digital mixer module. The second up-conversion digital mixer module outputs a first feedback signal to the first down-conversion digital mixer module. The first down-conversion digital mixer module outputs a down-converted signal, which is transmitted to the first up-conversion digital mixer module and the second down-conversion digital mixer module respectively. The up-converted signal output by the first up-conversion digital mixer module is wirelessly transmitted to the second patch antenna via the first RF transceiver chip and the first patch antenna. The second sine wave signal output by the initial signal frequency generation module is directly output as the output signal of the main transceiver.

[0008] The second patch antenna sequentially outputs the received signal to the second RF transceiver chip, the first bandpass filter, the third RF transceiver chip, and the third patch antenna before wirelessly transmitting it to the fourth patch antenna. The fourth patch antenna then sequentially transmits the received signal to the fourth RF transceiver chip, the second bandpass filter, the second down-conversion digital mixer module, and the frequency divider module. The frequency divider module and the second reference signal frequency generation module output the divided signal and the third sine wave signal, respectively, to the second up-conversion digital mixer module. The second up-conversion digital mixer module and the initial signal frequency generation module output the second feedback signal and the second sine wave signal, respectively, to the first down-conversion digital mixer module for down-conversion calculation, completing one closed-loop circuit of the remote closed-loop wireless phase coherent system. This closed-loop circuit is repeated several times, with the output of the first bandpass filter directly serving as the output signal of the slave transceiver. The output signals of the master transceiver and the slave transceiver always maintain phase coherence at different distances. By increasing the transceiver power, the operating distance of the remote wireless phase coherent system can be increased accordingly. The initial signal in the master transceiver and the output signal in the slave transceiver serve as the two output signals of the system. The two output signals are transmitted to the computer via a USB data cable, and their time-domain waveforms are plotted in the same coordinate system, which facilitates real-time observation of the phase relationship between the output signals at the master and slave ends.

[0009] The frequency of the third sine signal output by the second reference signal frequency generation module is half the frequency of the first sine signal output by the first reference signal frequency generation module; the three sine signals are generated based on the integrated circuit chip clock, and the initial phase of each signal is controllable; the three frequency digital domain sine signals have the same sampling rate, and the initial phase of each is zero.

[0010] The radio frequency transceiver chip includes a radio frequency signal source and a frequency conversion digital mixer module. The input signal of the radio frequency transceiver chip is input to the frequency conversion digital mixer module. The radio frequency signal source sends a radio frequency signal to the frequency conversion digital mixer module, which demodulates the input signal and outputs the input signal as the output of the radio frequency transceiver chip.

[0011] The digital mixing module includes a multiplier and a digital filter (BPF) connected in sequence. The two output signals of the digital mixing module are input to the multiplier, which outputs a sum frequency and a difference frequency signal, respectively. These signals are then input to the digital filter (BPF) to output the target single-frequency signal. During the digital mixing process, no second harmonic components or other interference will occur.

[0012] The frequency divider module includes a switch circuit, a D flip-flop, and a digital filter (BPF). The output of the switch circuit is connected to the CLK terminal of the D flip-flop, the D terminal of the D flip-flop is connected to its Q' terminal, and the Q terminal of the D flip-flop is connected to the input of the digital filter (BPF). The input signal of the frequency divider module is output as a square wave signal of the same frequency after passing through the switch circuit. This square wave signal is then input to the D flip-flop and outputs a divided signal. Finally, it is input to the digital filter (BPF) and outputs a fundamental signal. The frequency of the fundamental signal is half the frequency of the input signal. The frequency divider module not only eliminates the phase-locked loop (PLL) structure in analog systems but also amplifies the initial disturbance signal, achieves self-establishment of the loop, and simplifies the system workflow.

[0013] The wireless communication link between the first patch antenna of the master transceiver and the second patch antenna of the slave transceiver is in a different frequency band than the wireless communication link between the fourth patch antenna of the master transceiver and the third patch antenna of the slave transceiver. Specifically, they are in the 2.4GHz band and the 5GHz band, respectively, thus avoiding co-channel interference.

[0014] In the main transceiver, the radio frequency transceiver transmits signals through its antenna, which are received by the antenna in the secondary transceiver. The signals are amplified and down-converted to intermediate frequency (IF) signals in the radio frequency transceiver. Similarly, in the secondary transceiver, the radio frequency transceiver transmits signals through its antenna, which are received by the antenna in the main transceiver. The signals are amplified and down-converted to IF signals in the radio frequency transceiver.

[0015] The beneficial effects of this invention are:

[0016] 1. Compared with the analog system structure, in order to avoid transmitting and receiving at the same frequency, it is necessary to transmit radio frequency signals of three frequencies, including an additional reference signal. In this invention, digital domain signal processing realizes that there are only two radio frequency frequencies in the transmission link, which simplifies the structure and allows the use of radio frequency antennas that conform to WLAN communication standards.

[0017] 2. Compared with analog systems that use nonlinear devices to implement mixers, the digital domain mixer in this invention does not generate harmonic signals, thus avoiding interference signals.

[0018] 3. This invention uses D flip-flops and digital filters to implement a frequency divider circuit, which optimizes the phase-locked loop structure of the frequency divider module in the analog domain, reduces circuit complexity, and avoids additional uncertain time delays in the operation. At the same time, it solves the problem of signal loop establishment in analog circuits. Without the need for an external signal source, a correct and stable loop can be established only through the initial disturbance in the loop, thus optimizing the system workflow.

[0019] In summary, this invention introduces digital signal processing methods to achieve range-independent phase coherence between the master and slave transceivers, simplifies the structure of circuits such as phase-locked loop filters, possesses strong robustness, and avoids additional delay interference caused by harmonics and analog circuits. This invention can be applied to a wide range of fields such as beamforming, phased arrays, and bistatic radar systems. Attached Figure Description

[0020] Figure 1 This is a block diagram of the remote closed-loop wireless phase coherence system of the present invention;

[0021] Figure 2 This is a block diagram of the digital mixer module.

[0022] Figure 3 This is a block diagram of a digital frequency divider circuit.

[0023] Figure 4 This is a Simulink simulation diagram of the remote closed-loop wireless phase coherence system of the present invention.

[0024] Figure 5 (a) is the waveform of the output signal of the Simulink simulated master transceiver;

[0025] Figure 5 (b) is a Simulink simulation of the signal output from the transceiver;

[0026] Figure 6 (a) is a waveform diagram of the master-slave transceiver output signals when the communication distance changes abruptly in a Simulink simulation.

[0027] Figure 6 (b) is a magnified view of the master-slave transceiver output signal waveforms from 0.4s to 0.45s in the Simulink simulation of a sudden change in communication distance;

[0028] Figure 6 (c) is a magnified view of the master-slave transceiver output signal waveform from 0.48s to 0.53s in the Simulink simulation of a sudden change in communication distance;

[0029] Figure 6 (d) is a magnified view of the master-slave transceiver output signal waveforms from 0.9s to 0.95s in the Simulink simulation of a sudden change in communication distance;

[0030] In the diagram: 1. First reference signal frequency generation module; 2. Initial signal frequency generation module; 3. Second reference signal frequency generation module; 4. First down-conversion digital mixer module; 5. First up-conversion digital mixer module; 6. First RF transceiver chip; 7. First patch antenna; 8. Second patch antenna; 9. Second RF transceiver chip; 10. First bandpass filter; 11. Third RF transceiver chip; 12. Third patch antenna; 13. Fourth patch antenna; 14. Fourth RF transceiver chip; 15. Second bandpass filter; 16. Second down-conversion digital mixer module; 17. Divide-2 module; 18. Second up-conversion digital mixer module. Detailed Implementation

[0031] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0032] like Figure 1 As shown, the remote closed-loop wireless phase coherent system of the present invention includes a master transceiver and a slave transceiver, which are wirelessly connected. The master transceiver includes an integrated circuit chip, a first RF transceiver chip 6, a first patch antenna 7, a fourth patch antenna 13, a fourth RF transceiver chip 14, and a second bandpass filter 15. The integrated circuit chip is sequentially connected to the first RF transceiver chip 6 and the first patch antenna 7, and the fourth patch antenna 13 is sequentially connected to the second bandpass filter 15 and the integrated circuit chip. The slave transceiver includes a second patch antenna 8, a second RF transceiver chip 9, a first bandpass filter 10, a third RF transceiver chip 11, and a third patch antenna 12 connected in sequence. The first patch antenna 7 and the second patch antenna 8 are wirelessly connected, and the third patch antenna 12 and the fourth patch antenna 13 are wirelessly connected.

[0033] The integrated circuit chip includes a first reference signal frequency generation module 1, an initial signal frequency generation module 2, a second reference signal frequency generation module 3, a first down-conversion digital mixer module 4, a first up-conversion digital mixer module 5, a second down-conversion digital mixer module 16, a frequency divider module 17, and a second up-conversion digital mixer module 18. The first reference signal frequency generation module 1, the initial signal frequency generation module 2, and the second reference signal frequency generation module 3 generate three sinusoidal signals of different frequencies. The first sinusoidal signal output from the first reference signal frequency generation module 1 is output to the first up-conversion digital mixer module 5. The second sinusoidal signal output from the initial signal frequency generation module 2 is output to the first down-conversion digital mixer module 4. The second reference signal frequency generation module 5... The signal frequency generation module 3 outputs the third sine wave signal to the second up-conversion digital mixer module 18. The frequency divider module 17 outputs a disturbance signal to the second up-conversion digital mixer module 18. The second up-conversion digital mixer module 18 outputs a first feedback signal to the first down-conversion digital mixer module 4. The first down-conversion digital mixer module 4 outputs a down-converted signal, which is transmitted to the first up-conversion digital mixer module 5 and the second down-conversion digital mixer module 16 respectively. The up-converted signal output by the first up-conversion digital mixer module 5 is wirelessly transmitted to the second patch antenna 8 via the first RF transceiver chip 6 and the first patch antenna 7. The second sine wave signal output by the initial signal frequency generation module 2 is directly output as the output signal of the main transceiver.

[0034] The second patch antenna 8 sequentially outputs the received signal to the second RF transceiver chip 9, the first bandpass filter 10, the third RF transceiver chip 11, and the third patch antenna 12, and then wirelessly transmits it to the fourth patch antenna 13. The fourth patch antenna 13 sequentially transmits the received signal to the fourth RF transceiver chip 14, the second bandpass filter 15, the second down-conversion digital mixer module 16, and the divide-by-two module 17. The divide-by-two module 17 and the second reference signal frequency generation module 3 output the divided signal and the third sine signal to the second up-conversion digital mixer module 18, respectively. The second up-conversion digital mixer module 18 and the initial signal frequency generation module 2 output the second feedback signal and the second sine signal to the first down-conversion digital mixer module 4 for down-conversion calculation, completing one closed loop of the remote closed-loop wireless phase coherent system. The closed loop is repeated several times. The output of the first bandpass filter 10 is directly used as the output signal of the slave transceiver. The output signals of the master transceiver and the slave transceiver always maintain phase coherence at different distances. By increasing the transceiver power, the operating distance of the remote wireless phase-coherent system can be increased. The initial signal in the master transceiver and the output signal in the slave transceiver serve as the two output signals of the system. The two output signals are transmitted to the computer via a USB data cable, and their time-domain waveforms are plotted on the same coordinate system, which facilitates real-time observation of the phase relationship between the output signals at the master and slave ends.

[0035] The frequency of the third sine signal output by the second reference signal frequency generation module 3 is half the frequency of the first sine signal output by the first reference signal frequency generation module 1. The three sine signals are generated based on the clock of the integrated circuit chip, and the initial phase of each signal is controllable. The three frequency digital domain sine signals have the same sampling rate and the initial phase of each is zero.

[0036] The RF transceiver chips 6, 9, 11, and 14 include an RF signal source and a frequency conversion digital mixer module. The input signals of the RF transceiver chips 6, 9, 11, and 14 are input to the frequency conversion digital mixer module. The RF signal source sends an RF signal to the frequency conversion digital mixer module, which demodulates the input signal and outputs the input signal as the output of the RF transceiver chips 6, 9, 11, and 14.

[0037] like Figure 2 As shown, digital mixing modules 4, 5, 16, and 18 include a multiplier and a digital filter BPF connected in sequence. The two output signals of digital mixing modules 4, 5, 16, and 18 are input to the multiplier and output as a sum frequency and a difference frequency signal, respectively. These signals are then input to the digital filter BPF and output as the target single-frequency signal. During the digital mixing process, no second harmonic components or other interference will occur.

[0038] like Figure 3 As shown, the frequency divider module 17 includes a switch circuit, a D flip-flop, and a digital filter BPF. The output of the switch circuit is connected to the CLK terminal of the D flip-flop, the D terminal of the D flip-flop is connected to the Q' terminal of the D flip-flop, and the Q terminal of the D flip-flop is connected to the input of the digital filter BPF. The input signal of the frequency divider module 17 is output as a square wave signal of the same frequency after passing through the switch circuit. This square wave signal is then input to the D flip-flop and outputs a divided signal. Finally, it is input to the digital filter BPF and outputs a fundamental signal. The frequency of the fundamental signal is half the frequency of the input signal. The frequency divider module 17 not only eliminates the phase-locked loop structure in the analog system but also amplifies the initial disturbance signal, achieves self-establishment of the loop, and simplifies the system workflow.

[0039] The wireless communication link between the first patch antenna 7 of the master transceiver and the second patch antenna 8 of the slave transceiver is in a different frequency band than the wireless communication link between the fourth patch antenna 13 of the master transceiver and the third patch antenna 12 of the slave transceiver. Specifically, they are in the 2.4 GHz band and the 5 GHz band, respectively, thus avoiding co-channel interference.

[0040] In the main transceiver, radio frequency transceiver 6 transmits a signal through antenna 7, which is received by antenna 8 in the secondary transceiver. The signal is amplified and down-converted to an intermediate frequency signal in radio frequency transceiver 9. In the secondary transceiver, radio frequency transceiver 11 transmits a signal through antenna 12, which is received by antenna 13 in the main transceiver. The signal is amplified and down-converted to an intermediate frequency signal in radio frequency transceiver 14.

[0041] The working principle of a remote closed-loop wireless phase coherence system based on digital domain signal processing is as follows: Figure 1 As shown, the initial signal (ω0∠φ0) of the main transceiver is first down-converted to a lower frequency signal (ω′∠φ′), and then mixed with the reference frequency signal (ω1∠φ1). The mixed signal (ω′∠φ′) is then... a +ω1∠φ a +φ1) is input to the RF transceiver, its amplitude modulated onto the RF signal, and transmitted to the slave transceiver. Let the communication distance between the master and slave be L, then the signal transmission delay is t = L / c. Considering only the delay caused by spatial transmission, the signal received by the slave transceiver has a phase delay φ relative to the signal transmitted by the master transceiver. L = (ω1+ω′)L / c, where c is the propagation speed of electromagnetic waves in space. It is evident that this phase delay is related to the spatial transmission delay. Demodulation yields the signal received from the transceiver: (ω1+ω′∠φ1+φ′-φ)L / c. L This signal is then used as a feedback signal, modulated onto a radio frequency signal at another frequency, and transmitted back to the main transceiver.

[0042] The signal demodulated after reception by the main transceiver antenna is (ω1+ω′∠φ1+φ′-2φ). L The signal is first down-converted and mixed with the signal ω′∠φ′ to obtain the signal ω1∠φ1-2φ. L After passing through the frequency divider module, both its frequency and phase become half of their original values, i.e., ω1 / 2∠φ1 / 2 - φ1 / 2. L Then, it is mixed with the second reference signal (ω1 / 2∠φ1 / 2) to obtain the signal ω1∠φ1-φ L Since the reference signal is generated by the microcontroller's internal clock, the initial phase can be accurately controlled. Therefore, the frequency of the second reference signal and the initial phase are both half of the first reference frequency. The mixed signal is used as the input signal to perform frequency down-conversion on the initial signal (ω0∠φ0), resulting in the signal ω′∠φ′, where ω′=ω-ω1, φ′=φ0-φ1+φ L Substituting ω′ and φ′ into the output signal (ω1+ω′∠φ1+φ′-φ) from the transceiver... L We can obtain ω0∠φ0.

[0043] It can be seen that the received signal from the slave transceiver is at the same frequency as the initial signal from the master transceiver, and its phase is independent of the relative distance between the master and slave ends. Since the above structure does not consider the delay caused by circuit structure and computation, the signals at both ends have the same phase, with a phase difference of zero. In reality, the delay generated by each module of the circuit is a constant value, not changing with time or location. Therefore, the received signal from the slave transceiver is at the same frequency as the initial signal from the master transceiver and has a constant phase difference. This achieves long-range wireless phase coherence between the master and slave ends.

[0044] like Figure 4 As shown, a complete remote closed-loop wireless phase coherence simulation system was built in Simulink. The initial signal frequency (second sine wave) of the master transceiver was set to 455Hz, the first reference frequency (first sine wave) to 144Hz, and the second reference frequency (second sine wave) to 72Hz. A variable delay module was used to simulate the phase delay caused by communication distance, and a step signal module was used to simulate the phase delay abrupt change caused by distance change. The step time was set to 0.5s, with an initial value of 1e-4s and a final value of 6e-4s. The output signals of the master and slave transceivers were acquired and displayed through an oscilloscope module. The simulation duration was set to 1s, and the simulation model was run. Figure 5 As shown in (a), in the first 0.5 seconds, the main transceiver output signal is a standard sine wave; as Figure 5 As shown in (b), from the moment the transceiver starts to generate a disturbance, the signal gradually amplifies. After the signal stabilizes, it becomes a sinusoidal signal with the same frequency as the main transceiver's output signal. Figure 6 As shown in (b), the output signal of the master and slave transceivers is a stable sine wave signal within the time period of 0.4s to 0.55s, with a peak time difference of 0.0008s and a phase difference of 131.04°; Figure 6 (a) and Figure 6 As shown in (c), due to the introduction of a step signal at 0.5s, the simulated communication distance undergoes a sudden change, resulting in a sudden change in the phase of the transceiver output signal. The peak time difference is 0.0013s, and the phase difference is 212.94°. Figure 6 (a) and Figure 6 As shown in (d), after the introduction of the step signal, the output signal from the transceiver fluctuates. After several round-loop operations, it converges back to a standard sine wave signal. Observing the waveform in the time interval of 0.9s to 0.95s, it is found that the frequency of the output signal from the transceiver is the same as that of the main transceiver output signal, and the peak time difference recovers to 0.0008s before the introduction of the step signal, with a phase difference of 131.04°. Figure 6 The phase difference results in (b) are the same, proving that the master and slave transceivers in this system can achieve long-range phase coherence at different distances. Therefore, the correctness of the above theory and system is verified by Simulink simulation. Figure 6 The horizontal axis represents time (s), and the vertical axis represents the signal amplitude.

[0045] In summary, the main advantage of this invention lies in achieving remote wireless phase coherence using digital signal processing methods. The feedback loop operation is implemented in the digital domain, using a microcontroller to replace modules such as mixers and frequency dividers in traditional methods, simplifying the circuit structure and avoiding additional uncertain time delays during operation. Using digital signal processing to implement the mixer prevents the generation of second harmonics, reducing interference signals in the circuit and improving the signal-to-noise ratio. Secondly, it also solves the signal loop establishment problem in analog systems, eliminating the need to introduce an additional signal source to replace the feedback signal in establishing the signal loop; the initial fluctuation signal can be amplified through the frequency divider module 17.

Claims

1. A long-range closed-loop wireless phase coherent system based on digital domain signal processing, characterized in that: The system includes a master transceiver and a slave transceiver, which are wirelessly connected. The feedback loop operation of the remote closed-loop wireless phase coherence system is implemented in the digital domain. The master transceiver includes an integrated circuit chip, a first RF transceiver chip (6), a first patch antenna (7), a fourth patch antenna (13), a fourth RF transceiver chip (14), and a second bandpass filter (15). The integrated circuit chip is connected to the first RF transceiver chip (6) and the first patch antenna (7) in sequence. The fourth patch antenna (13) is connected to the fourth RF transceiver chip (14), the second bandpass filter (15), and the integrated circuit chip in sequence. The slave transceiver includes a second patch antenna (8), a second RF transceiver chip (9), a first bandpass filter (10), a third RF transceiver chip (11), and a third patch antenna (12) connected in sequence. The first patch antenna (7) and the second patch antenna (8) are wirelessly connected, and the third patch antenna (12) and the fourth patch antenna (13) are wirelessly connected. The integrated circuit chip includes a first reference signal frequency generation module (1), an initial signal frequency generation module (2), a second reference signal frequency generation module (3), a first down-conversion digital mixer module (4), a first up-conversion digital mixer module (5), a second down-conversion digital mixer module (16), a frequency divider module (17), and a second up-conversion digital mixer module (18). The first reference signal frequency generation module (1), the initial signal frequency generation module (2), and the second reference signal frequency generation module (3) generate three different digital domain sinusoidal signals. The integrated circuit chip mixes and converts the initial signal from the master transceiver and the feedback signal from the slave transceiver, and outputs an up-converted signal; the up-converted signal is input to the first radio frequency transceiver chip (6), the amplitude is modulated onto the radio frequency signal, and wirelessly transmitted to the second patch antenna (8) via the first patch antenna (7). The frequency divider module (17) amplifies the initial disturbance signal and realizes the self-establishment of the loop, so that the output signal of the transceiver changes from no signal to disturbance, the signal is gradually amplified until it stabilizes into a sine wave signal, and the frequency is the same as the frequency of the output signal of the main transceiver. The frequency band of the wireless communication link between the first patch antenna (7) of the master transceiver and the second patch antenna (8) of the slave transceiver is different from the frequency band of the wireless communication link between the fourth patch antenna (13) of the master transceiver and the third patch antenna (12) of the slave transceiver; digital domain signal processing is used to achieve only two radio frequency frequencies in the transmission link, while avoiding co-channel interference.

2. The remote closed-loop wireless phase coherent system based on digital domain signal processing according to claim 1, characterized in that: The first reference signal frequency generation module (1) outputs a first sine wave signal to the first up-conversion digital mixer module (5), the initial signal frequency generation module (2) outputs a second sine wave signal to the first down-conversion digital mixer module (4), the second reference signal frequency generation module (3) outputs a third sine wave signal to the second up-conversion digital mixer module (18), the frequency divider module (17) outputs a frequency divider signal to the second up-conversion digital mixer module (18), the second up-conversion digital mixer module (18) outputs a feedback signal to the first down-conversion digital mixer module (4), the first down-conversion digital mixer module (4) outputs a down-conversion signal which is transmitted to the first up-conversion digital mixer module (5) and the second down-conversion digital mixer module (16) respectively, and the up-conversion signal output by the first up-conversion digital mixer module (5) is wirelessly transmitted to the second patch antenna (8) via the first radio frequency transceiver chip (6) and the first patch antenna (7) in sequence. The second patch antenna (8) sequentially outputs the received signal to the second RF transceiver chip (9), the first bandpass filter (10), the third RF transceiver chip (11), and the third patch antenna (12), and then wirelessly transmits it to the fourth patch antenna (13). The fourth patch antenna (13) sequentially transmits the received signal to the fourth RF transceiver chip (14), the second bandpass filter (15), the second down-conversion digital mixer module (16), and the divide-by-two module (17). The divide-by-two module (17) and the second reference signal frequency generation module (3) respectively... The output frequency division signal and the third sine signal are sent to the second up-conversion digital mixer module (18). The second up-conversion digital mixer module (18) and the initial signal frequency generation module (2) respectively output feedback signals and the second sine signal to the first down-conversion digital mixer module (4) for down-conversion operation, thus completing one closed loop of the remote closed-loop wireless phase coherent system. The closed loop is repeated several times. The output of the first bandpass filter (10) is directly used as the output signal of the slave transceiver. The output signal of the master transceiver and the output signal of the slave transceiver always remain in phase coherence.

3. A remote closed loop wireless phase coherent system based on digital domain signal processing as claimed in claim 2, wherein: The frequency of the third sine signal output by the second reference signal frequency generation module (3) is half the frequency of the first sine signal output by the first reference signal frequency generation module (1).

4. The remote closed loop wireless phase coherent system based on digital domain signal processing according to claim 1, characterized in that: The first RF transceiver chip (6), the second RF transceiver chip (9), the third RF transceiver chip (11), and the fourth RF transceiver chip (14) all include an RF signal source and a frequency conversion digital mixing module. The input signals of the first RF transceiver chip (6), the second RF transceiver chip (9), the third RF transceiver chip (11), and the fourth RF transceiver chip (14) are input to the frequency conversion digital mixing module. The RF signal source sends an RF signal to the frequency conversion digital mixing module, which processes the input signal and outputs the input signal as the output of the first RF transceiver chip (6), the second RF transceiver chip (9), the third RF transceiver chip (11), and the fourth RF transceiver chip (14).

5. A digital domain signal processing based remote closed loop wireless phase coherent system according to claim 1, characterized in that: The first down-conversion digital mixer module (4), the first up-conversion digital mixer module (5), the second down-conversion digital mixer module (16), and the second up-conversion digital mixer module (18) all include a multiplier and a digital filter BPF connected in sequence. The two input signals of the first down-conversion digital mixer module (4), the first up-conversion digital mixer module (5), the second down-conversion digital mixer module (16), and the second up-conversion digital mixer module (18) are input to the multiplier and output as a sum frequency and a difference frequency signal, respectively. Then, they are input to the digital filter BPF and output as a target single-frequency signal.

6. A digital domain signal processing based remote closed loop wireless phase coherent system as claimed in claim 1, wherein: The frequency divider module (17) includes a switch circuit, a D flip-flop, and a digital filter BPF. The output of the switch circuit is connected to the CLK terminal of the D flip-flop, the D terminal of the D flip-flop is connected to the Q' terminal of the D flip-flop, and the Q terminal of the D flip-flop is connected to the input of the digital filter BPF. The input signal of the frequency divider module (17) is output as a square wave signal of the same frequency after passing through the switch circuit. Then it is input to the D flip-flop and outputs a frequency-divided signal. Finally, it is input to the digital filter BPF and outputs a fundamental wave signal. The frequency of the fundamental wave signal is half the frequency of the input signal.

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