Multi-node local oscillator signal phase synchronization method and system

Abstract

The invention belongs to the technical field of phase synchronization, and provides a multi-node local oscillator signal phase synchronization method and system in order to solve the problems that existing multi-node local oscillator signal phase synchronization has error accumulation, depends on external reference signals and the like. The master node calculates a phase delay compensation value between the master node and the slave node through signal frequency multiplication loopback and real-time phase discrimination; and the slave node performs phase compensation on the received local oscillation signal based on the phase delay compensation value, and outputs the local oscillation signal after phase compensation as the local oscillation signal of the slave node, thereby realizing local oscillation signal phase synchronization between the master node and the slave node. The frequency drift directions and sizes of the local oscillator signals on all the nodes are the same, so that the problem of frequency synchronization in an existing method is avoided, and the problem of signal phase synchronization can be solved directly.

Description

Technical Field

[0001] The present invention belongs to the technical field related to phase synchronization, and in particular relates to a multi-node local oscillator signal phase synchronization method and system. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] Multi-node signal synchronization is of great significance for distributed radar and distributed communication. At present, the research on multi-node synchronization mainly focuses on time and frequency synchronization, while there are few research results on signal phase synchronization, especially local oscillator signal synchronization. For fully coherent distributed radar, it is necessary for multi-node transmitting and receiving signals to meet high coherence. The local oscillator signal is the metronome of the entire radar system, providing basic frequency reference for the transmitting and receiving channels. The phase synchronization performance of the spatially separated multi-node local oscillator signals is of decisive significance to the detection performance of the distributed radar.

[0004] In the prior art, patent CN117792599A proposes a dual-system phase synchronization method, device, electronic device, medium and program product. The dual systems use independent local oscillators, and the two time-frequency phase systems exchange timestamps to realize signal frequency and clock error detection and perform signal parameter calibration, and finally realize dual-system signal phase synchronization. This method requires frequency calibration, clock calibration and then phase synchronization between the dual systems. The process is relatively complicated, and there is error accumulation in the implementation process, making it difficult to obtain a high phase synchronization accuracy. Patent CN112134678A proposes a dual-node phase synchronization method, which uses radar carrier synchronization pulses to transmit bidirectionally to obtain the frequency difference and phase noise signals between the two nodes, and uses them to compensate for the received echo and realize the received phase synchronization. This method realizes echo phase synchronization, which is invalid for fully coherent transmission synchronization.

[0005] The difficulty of phase synchronization of multi-node local oscillator signals lies in the inconsistency of frequency drift between different frequency sources. Currently, there are two main ways to solve this problem: One is to use an external highly stable frequency source as a reference, such as the GPS timing signal. Each node uses a phase-locked loop to achieve signal frequency taming, and then achieves phase synchronization by exchanging synchronization signals. This type of method is heavily dependent on external reference signals and is not applicable to many ground-based or space-based distributed radars. The second is to directly exchange time-stamped synchronization signals between the master and slave nodes to achieve phase synchronization based on frequency synchronization and clock synchronization. The process is more complicated and error accumulation is difficult to avoid. Summary of the invention

[0006] In order to overcome the shortcomings of the above-mentioned prior art, the present invention provides a multi-node local oscillator signal phase synchronization method and system, in which the same source signal is phase synchronized with itself at different nodes, and the direction and magnitude of the frequency drift of the local oscillator signal at each node are the same, thereby avoiding the frequency synchronization problem in the existing method and achieving high-precision phase synchronization between multiple nodes.

[0007] In order to achieve the above object, the present invention adopts the following technical solution: In a first aspect, the present invention provides a multi-node local oscillator signal phase synchronization method, wherein the multi-nodes include a master node and at least one slave node, and the method includes: The master node distributes the generated local oscillator signal to at least one slave node; The master node calculates the phase delay compensation value between the master node and the slave node through a signal frequency multiplication loop and real-time phase detection; The slave node performs phase compensation on the received local oscillator signal based on the phase delay compensation value, and outputs the local oscillator signal after phase compensation as the local oscillator signal of the slave node, thereby achieving phase synchronization of the local oscillator signals between the master and slave nodes.

[0008] In a second aspect, the present invention provides a multi-node local oscillator signal phase synchronization system, comprising a master node and at least one slave node, wherein: A master node, used to distribute the generated local oscillator signal to at least one slave node; and calculate the phase delay compensation value between the master node and the slave node through a signal frequency multiplication loop and real-time phase discrimination; The slave node is used to perform phase compensation on the received local oscillator signal based on the phase delay compensation value, and output the local oscillator signal after phase compensation as its own local oscillator signal, so as to achieve phase synchronization of the local oscillator signals between the master and slave nodes.

[0009] One or more of the above technical solutions have the following beneficial effects: The present invention adopts a mode in which the master node distributes the local oscillator signal externally, and the slave node does not use an independent crystal oscillator, but outputs the received local oscillator signal of the master node as its own local oscillator signal after phase compensation. The master node calculates the phase delay compensation value between the master and slave nodes through signal frequency multiplication loop and real-time phase discrimination, and the slave node performs phase compensation on the received local oscillator signal based on the phase delay compensation value, thereby realizing the phase synchronization of the local oscillator signals of the master and slave nodes. The present invention is that the homologous signal is phase synchronized with itself at different nodes, and the direction and magnitude of the frequency drift of the local oscillator signal at each node are the same, thereby avoiding the problem of frequency synchronization in the existing method, and can directly focus on solving the signal phase synchronization problem.

[0010] The master node of the present invention can be matched with multiple slave nodes, and the multiple slave nodes can simultaneously receive the local oscillator signal distributed by the master node and perform phase synchronization with the master node respectively, thereby forming phase synchronization of the local oscillator signals of multiple nodes, which has better scalability than the existing method.

[0011] Advantages of additional aspects of the present invention will be given in part in the following description, and in part will become obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0013] Figure 1 It is a structural block diagram of a local oscillator signal distribution and phase synchronization device in an embodiment of the present invention; Figure 2 The output phase of the first phase detector in the embodiment of the present invention is The corresponding relationship diagram between them; Figure 3 The output phase of the second phase detector in the embodiment of the present invention is The corresponding relationship diagram between them; Figure 4 is the difference between the outputs of the first phase detector and the second phase detector in the embodiment of the present invention and The corresponding relationship diagram. DETAILED DESCRIPTION

[0014] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0015] It should be noted that the terms used herein are for describing specific embodiments only and are not intended to be limiting of exemplary embodiments according to the present invention.

[0016] In the absence of conflict, the embodiments of the present invention and the features of the embodiments may be combined with each other.

[0017] This embodiment discloses a multi-node local oscillator signal phase synchronization system, including a master node and at least one slave node, wherein: A master node, used to distribute the generated local oscillator signal to at least one slave node; and calculate the phase delay compensation value between the master node and the slave node through a signal frequency multiplication loop and real-time phase discrimination; The slave node is used to perform phase compensation on the received local oscillator signal based on the phase delay compensation value, and output the local oscillator signal after phase compensation as its own local oscillator signal, so as to achieve phase synchronization of the local oscillator signals between the master and slave nodes.

[0018] This embodiment adopts a mode in which the master node distributes the local oscillator signal to the outside. The slave node does not use an independent crystal oscillator, but instead outputs the received local oscillator signal of the master node as its own local oscillator after phase compensation. The master node obtains the delay phase of the receiving and transmitting channels between the master and slave nodes through signal frequency multiplication loopback and real-time phase discrimination, and calculates the phase delay compensation value; the slave node obtains the phase delay compensation value through the communication channel, performs phase compensation on the local oscillator signal it receives, and outputs the compensated local oscillator signal as its own local oscillator signal, thereby achieving phase synchronization of the local oscillator signals of the master and slave nodes.

[0019] This embodiment does not require an external frequency source to provide a reference signal. The master node uses a crystal oscillator circuit with a highly stable frequency. The signal frequency drift during the distribution, reception and loopback of the local oscillator signal is negligible, and the signal phase difference between the master and slave nodes is only related to the delay of the signal propagation channel.

[0020] The master node can be matched with multiple slave nodes. Multiple slave nodes can simultaneously receive the local oscillator signal distributed by the master node and perform phase synchronization with the master node respectively, thereby forming the phase synchronization of the local oscillator signal of multiple nodes. Figure 1 A local oscillator signal phase synchronization system including a master node and a slave node is described in detail as an example: The main node includes: a crystal oscillator module, a transmitting end power divider, a first receiving end power divider, an amplifying transmitting circuit and an antenna, an amplifying receiving circuit and an antenna, a double frequency multiplier, a triple frequency multiplier, a first phase detector, namely phase detector A, a second phase detector, namely phase detector B, a double frequency bandpass filter, a triple frequency bandpass filter, a first calculation control unit, a data communication unit and an antenna.

[0021] Among them, the crystal oscillator module is used to generate a local oscillator signal; A power divider at the transmitting end is used to divide the local oscillator signal into a distribution signal and a phase-detection reference signal; A first receiving end power divider is used to divide the received signal into two signals, which are used as inputs of a 2x bandpass filter and a 3x bandpass filter respectively; 2x frequency bandpass filter, used to separate the 2x frequency signal in the loopback channel; A 3x frequency bandpass filter is used to separate the 3x frequency signal in the loopback channel; The first phase detector and the second phase detector are respectively used to perform phase detection on signals with different frequency multiplication; The first calculation control unit is used to calculate the phase delay compensation value according to the phase detection results of the first phase detector and the second phase detector.

[0022] The slave node includes: a second receiving end power divider, a transmitting end combiner, an amplifying transmitting circuit and an antenna, an amplifying receiving circuit and an antenna, a frequency doubler, a frequency tripler, a digital phase shifter, a calculation control unit, a data communication unit and an antenna.

[0023] The second receiving end power divider is used to distribute the received local oscillator signal into a first signal, a second signal and a third signal; A frequency doubler, used for processing the second signal by doubling its frequency; A 3-fold frequency multiplier, used for performing 3-fold frequency processing on the third channel signal; A second calculation control unit, used for generating a phase shift instruction according to the phase delay compensation value and sending the instruction to the digital phase shifter; The digital phase shifter is used to perform phase compensation on the first signal.

[0024] This embodiment requires that the signal frequency output by the crystal oscillator module of the master node has high stability, and the frequency drift within the signal loopback period is negligible; the transceiver circuits in the local oscillator signal transmission channel and the loopback channel have good consistency, and the signal phase delays of all components are measurable and stable.

[0025] In this embodiment, the master node distributes the local oscillator signal to the slave node through a wireless channel. After receiving the local oscillator signal, the slave node divides it into a first signal, a second signal and a third signal; the first signal is output as the local oscillator signal of the slave node after phase compensation; in addition, the second signal and the third signal are sent back to the master node through a loop channel after different frequency multiplication and phase detection; the master node uses the difference between the outputs of the two phase detectors to solve the signal phase delay between the master and slave nodes, and sends the phase delay compensation value to the slave node; finally, the local oscillator signal of the slave node achieves high-precision phase synchronization with the local oscillator signal of the master node through active phase compensation.

[0026] The specific implementation process of the local oscillator signal phase synchronization system is as follows: The local oscillator signal of the master node is divided into four paths, which are used for: 1. As the local oscillator signal of the master node; 2. Distributing signals to slave nodes; 3. Doubling the frequency as the reference signal of the first phase detector; 4. Tripling the frequency as the reference signal of the second phase detector.

[0027] Among them, the initial phases of the four signals output by the transmitter power divider are the same, which can be expressed as .

[0028] The slave node receives the local oscillator signal distributed by the master node, and after passing through the amplification receiving circuit, it is divided into three outputs by the second receiving end power divider. Among them, the first signal enters the digital phase shifter and is used as the slave node local oscillator signal after phase compensation; the second signal is doubled and sent to the loop channel; the third signal is tripled and sent to the loop channel.

[0029] Among them, the initial phases of the three outputs of the second receiving end power divider are the same, which can be expressed as .

[0030] Assume that the channel phase delay between the local oscillator signal transmitted from the master node and received by the slave node is:

[0031] Where K is a positive integer, It indicates that the channel delay is less than one cycle of the phase residual, which is also the key to the phase compensation of the local oscillator signal from the node.

[0032] From the node perspective, the phase of the output signal of the second receiving end power divider is:

[0033] in, It represents the phase delay caused by the power divider, which is usually linear with the operating frequency. Stable and measurable, after phase shift compensation Can be ignored.

[0034] It should be noted that the phase delays caused by the transmitting end power divider, the first receiving end power divider and the second receiving end power divider described in this embodiment are the same, so they are unified as Represents the phase delay of the power divider.

[0035] The slave node doubles and triples the second signal and the third signal output by the second receiving end power divider respectively, passes through the transmitting end combiner, and then sends them back to the master node through the wireless channel to form a signal loop.

[0036] The master node separates the received loopback signal through a 2x frequency bandpass filter, and the 2x frequency signal is connected to the first phase detector to perform phase detection with its reference signal.

[0037] The first phase detector reference signal phase It can be expressed as:

[0038] in, Represents the phase delay caused by the 2-frequency multiplier.

[0039] The phase of the loop signal connected to the first phase detector It is expressed as:

[0040] in, Indicates the local oscillator phase delay caused by the combiner. represents the local oscillator phase delay caused by the power divider, Represents the phase delay caused by a 2-octave bandpass filter.

[0041] Then the output of the first phase detector should be expressed as:

[0042]

[0043] in, It indicates the phase delay caused by the power divider, combiner and 2x bandpass filter on the 2x frequency loopback branch. The above values ​​can be measured in advance and after fixed phase compensation, Can be ignored. K is a positive integer.

[0044] Therefore, the output of the first phase detector can be expressed as:

[0045] because , and There is a fuzzy correspondence between them, and the relationship graph is as follows Figure 2 shown.

[0046] Similarly, the 3x frequency loopback signal is connected to the second phase detector, and its phase is expressed as :

[0047] in, represents the phase delay caused by the 3-frequency multiplier, represents the phase delay of a 3-octave bandpass filter.

[0048] The reference signal of the second phase detector is expressed as:

[0049] The output of the second phase detector is:

[0050] in,

[0051] Similar to the conclusion of the first phase detector, the output of the second phase detector can be expressed as:

[0052] in, It indicates the phase delay caused by the power divider, combiner and 3x bandpass filter on the 3x loop branch.

[0053] because , and There is a fuzzy correspondence between them, and the relationship graph is as follows Figure 3 shown.

[0054] The outputs of the first phase detector and the second phase detector are sent to the first calculation control unit of the master node to calculate the parameters: The calculation results are as follows Figure 4 As shown, and There is an unambiguous correspondence between them.

[0055] The master node sends the calculation result to the slave node through the data communication unit, and the second calculation control unit of the slave node generates a phase shift instruction according to the data and sends it to the digital phase shifter.

[0056] The digital phase shifter performs phase compensation on the output of the second receiving end power divider of the slave node, and the phase of the output signal is:

[0057] At this time, the local oscillator signals output by the slave node and the master node meet the same frequency and phase.

[0058] This embodiment discloses a multi-node local oscillator signal phase synchronization method, where the multi-nodes include a master node and at least one slave node, including: The master node distributes the generated local oscillator signal to at least one slave node; The master node calculates the phase delay compensation value between the master node and the slave node through signal frequency multiplication loop and real-time phase detection; The slave node performs phase compensation on the received local oscillator signal based on the phase delay compensation value, and outputs the phase-compensated local oscillator signal as the local oscillator signal of the slave node, thereby achieving phase synchronization of the local oscillator signals between the master and slave nodes.

[0059] As an implementation method, the master node calculates the phase delay compensation value between the master node and the slave node through a signal frequency multiplication loop and real-time phase detection, specifically: After receiving the local oscillator signal from the master node, the slave node divides the local oscillator signal into a first signal, a second signal and a third signal; the second signal and the third signal are sent back to the master node through a loop channel after different frequency multiplication, and the master node uses two phase detectors to perform phase difference detection and calculate the phase delay compensation value between the master node and the slave node.

[0060] Specifically, the second signal and the third signal are processed by doubling and tripling the frequencies respectively, and then sent back to the master node through the loopback channel; The master node performs phase difference detection on the double frequency signal and the triple frequency signal received by the first phase detector and the second phase detector respectively, to obtain a first phase detection result and a second phase detection result; The master node calculates a phase delay compensation value between the master node and the slave node according to the difference between the first phase detection result and the second phase detection result.

[0061] This embodiment uses the phase detection results of two loop signals with phase ambiguity to obtain the unambiguous phase estimation of the local oscillator signal. That is, the phase detection results of the 2x and 3x loop signals are both phase ambiguous when viewed separately, but the difference between the two has a one-to-one correspondence with the signal phase delay between the master and slave nodes, so as to calculate and obtain accurate phase compensation.

[0062] In this embodiment, only the master node has an independent crystal oscillator for generating the local oscillator signal, and the slave node has no independent signal source, so the entire system is a homologous signal that performs phase synchronization with itself at different nodes. The direction and magnitude of the frequency drift of the local oscillator signal at each node are the same, thereby avoiding the frequency synchronization problem in the existing method and directly focusing on solving the signal phase synchronization problem.

[0063] Although the above describes the specific implementation mode of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without creative work are still within the scope of protection of the present invention.

Claims

1. A multi-node local oscillator signal phase synchronization method, characterized in that: The multiple nodes include a master node and at least one slave node, and the method includes: The master node distributes the generated local oscillator signal to at least one slave node; The master node calculates the phase delay compensation value between the master node and the slave node through a signal frequency multiplication loop and real-time phase detection; The slave node performs phase compensation on the received local oscillator signal based on the phase delay compensation value, and outputs the local oscillator signal after phase compensation as the local oscillator signal of the slave node, thereby achieving phase synchronization of the local oscillator signals between the master and slave nodes.

2. A multi-node local oscillator signal phase synchronization method as claimed in claim 1, characterized in that: The master node calculates the phase delay compensation value between the master node and the slave node through a signal frequency multiplication loop and real-time phase detection, specifically: After the slave node receives the local oscillator signal of the master node, it divides the local oscillator signal into a first signal, a second signal and a third signal; the second signal and the third signal are sent back to the master node through a loop channel after different frequency multiplication, and the master node uses two phase detectors to perform phase difference detection and calculate the phase delay compensation value between the master node and the slave node.

3. A multi-node local oscillator signal phase synchronization method as claimed in claim 2, characterized in that: The second signal and the third signal are sent back to the master node through the loop channel after different frequency multiplication. The master node uses two phase detectors to perform phase difference detection and calculate the phase delay compensation value between the master node and the slave node, specifically: The second signal and the third signal are respectively processed by doubling and tripling the frequency, and then sent back to the master node through the loopback channel; The master node performs phase difference detection on the received double frequency signal and triple frequency signal through the first phase detector and the second phase detector respectively, to obtain a first phase detection result and a second phase detection result; The master node calculates a phase delay compensation value between the master node and the slave node according to a difference between the first phase detection result and the second phase detection result.

4. A multi-node local oscillator signal phase synchronization method as claimed in claim 2, characterized in that: The slave node adjusts the phase compensation amount of the digital phase shifter for the first signal according to the phase delay compensation value.

5. A multi-node local oscillator signal phase synchronization method as claimed in claim 2, characterized in that: The initial phases of the first signal, the second signal and the third signal are the same.

6. A multi-node local oscillator signal phase synchronization method as claimed in claim 1, characterized in that: The master node performs phase synchronization with the plurality of slave nodes simultaneously, and each slave node independently performs phase compensation to achieve phase synchronization of multi-node local oscillator signals.

7. A multi-node local oscillator signal phase synchronization system, characterized in that: It includes a master node and at least one slave node, wherein: A master node, used to distribute the generated local oscillator signal to at least one slave node; and calculate the phase delay compensation value between the master node and the slave node through a signal frequency multiplication loop and real-time phase discrimination; The slave node is used to perform phase compensation on the received local oscillator signal based on the phase delay compensation value, and output the local oscillator signal after phase compensation as its own local oscillator signal, so as to achieve phase synchronization of the local oscillator signals between the master and slave nodes.

8. A multi-node local oscillator signal phase synchronization system as claimed in claim 7, characterized in that: The master node includes a crystal oscillator module, a transmitting end power divider, a first receiving end power divider, a first phase detector, a second phase detector and a first calculation control unit; wherein: The crystal oscillator module is used to generate a local oscillator signal; The transmitting end power divider is used to divide the local oscillator signal into multiple distribution signals; The first receiving end power divider is used to divide the received signal into two signals, which are respectively used as inputs of different frequency multiplication bandpass filters; The first phase detector and the second phase detector are respectively used to perform phase detection on signals with different frequency multiplication; The first calculation control unit is used to calculate the phase delay compensation value according to the phase detection results of the first phase detector and the second phase detector.

9. A multi-node local oscillator signal phase synchronization system as claimed in claim 7, characterized in that: The slave node includes a second receiving end power divider, a digital phase shifter, a frequency multiplier, and a second calculation control unit; wherein: The second receiving end power divider is used to distribute the received local oscillator signal into a first signal, a second signal and a third signal; The frequency multiplier is used to perform different frequency multiplication processing on the second signal and the third signal; The second calculation control unit is used to generate a phase shift instruction according to the phase delay compensation value and send it to the digital phase shifter; The digital phase shifter is used to perform phase compensation on the first signal.

10. A multi-node local oscillator signal phase synchronization system as claimed in claim 7 or 8, characterized in that: The different frequency-multiplication bandpass filters are used to separate the corresponding frequency-multiplication signals in the loopback signal.

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