Radio frequency signal stable-phase transmission device and method

Abstract

The invention discloses a radio frequency signal stable-phase transmission device and method, and the device comprises a reference source which comprises an optical reference source and a radio frequency reference source; the client comprises a voltage-controlled phase shifter, a phase discriminator and a controller, the voltage-controlled phase shifter adjusts the radio frequency synchronizing signal to obtain an adjusted radio frequency signal, the phase discriminator obtains an error signal according to the pulse laser synchronizing signal and the adjusted radio frequency signal, the controller obtains a control voltage according to the error signal, and the control voltage is controlled by the voltage-controlled phase shifter. And based on the control voltage, the voltage-controlled phase shifter is controlled, so that the voltage-controlled phase shifter adjusts the radio frequency synchronization signal, thereby outputting a phase-locked radio frequency signal. The phase drift generated in the transmission process of the radio frequency signal can be reflected to the error signal, and the phase-locked radio frequency signal can be obtained through negative feedback control of the controller, so that the phase synchronization relation between the phase-locked radio frequency signal and the pulse laser synchronizing signal is kept.

Description

Technical Field

[0001] This invention relates to the field of time synchronization technology, and more particularly to a device and method for stable phase transmission of radio frequency signals. Background Technology

[0002] With the development of large-scale scientific facilities such as free-electron lasers (FELs), synchrotron radiation facilities, and large-scale telescope arrays, maintaining strict time synchronization between multiple systems at the picosecond or even femtosecond level has become a key technological foundation for ensuring stable operation and experimental accuracy. These facilities typically include a radio frequency master oscillator (RMO) to provide a radio frequency synchronization reference, and an optical master oscillator (OMO) to generate pulsed laser synchronization signals. These signals are then distributed over kilometer-scale distances via stable phase-locked fiber optic transmission links, maintaining extremely low jitter and drift even during long-distance transmission. Therefore, how to fully utilize the advantages of stable phase-locked fiber optic links to distribute the radio frequency synchronization signal with high precision to each subsystem and achieve phase-locked synchronization between them has become a critical technical problem that urgently needs to be solved.

[0003] In existing technologies, the synchronization signal generated by the RMO is directly distributed to each client via an RF coaxial cable. This method has the simplest structure, but long-distance coaxial cables are extremely sensitive to temperature changes and mechanical disturbances, resulting in significant RF phase drift, which is difficult to meet the long-term stability and ultra-high synchronization accuracy requirements of devices such as FELs. To reduce the temperature drift of the coaxial cable itself, it is placed in a temperature-controlled pipe to form a temperature-controlled phase-stable link. This method can significantly reduce phase drift caused by changes in ambient temperature, but it requires a bulky temperature control structure for a long coaxial link, making engineering implementation complex and costly. Moreover, it is a passive suppression method with limited ability to compensate for sudden disturbances and residual drift.

[0004] Therefore, existing technologies still need improvement and development. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide an apparatus and method for stable phase transmission of radio frequency signals, in order to address the above-mentioned deficiencies of the prior art and to solve the problem of asynchrony caused by phase drift in the transmission of radio frequency signals in the prior art.

[0006] The technical solution adopted by this invention to solve the technical problem is as follows: An apparatus for stable phase transmission of radio frequency signals, comprising: The reference source includes an optical reference source and an radio frequency (RF) reference source, wherein the optical reference source and the RF reference source are in a synchronized state, the optical reference source is configured to distribute a pulsed laser synchronization signal, and the RF reference source is configured to distribute an RF synchronization signal. At least one client includes a voltage-controlled phase shifter, a phase detector, and a controller. The voltage-controlled phase shifter is configured to adjust the radio frequency synchronization signal to obtain an adjusted radio frequency signal. The phase detector is configured to obtain an error signal based on the pulsed laser synchronization signal and the adjusted radio frequency signal. The controller is configured to obtain a control voltage based on the error signal and control the voltage-controlled phase shifter based on the control voltage, so that the voltage-controlled phase shifter adjusts the radio frequency synchronization signal to output a phase-locked radio frequency signal.

[0007] The aforementioned device for stable phase transmission of radio frequency signals, wherein the radio frequency reference source is a radio frequency master oscillator, and the radio frequency master oscillator is connected to the voltage-controlled phase shifter through a radio frequency transmission link.

[0008] The device for stable phase transmission of radio frequency signals, wherein the optical reference source is a reference laser, and the reference laser is connected to the phase detector through a stable phase fiber optic link.

[0009] The aforementioned apparatus for stable phase transmission of radio frequency signals, wherein the phase detector comprises: An electro-optic phase modulation unit is configured to cause the pulsed laser synchronization signal and the adjusted radio frequency signal to undergo phase-dependent electro-optic phase modulation. A balance detector is configured to output an error signal characterizing the relative phase deviation between the pulsed laser synchronization signal and the radio frequency signal.

[0010] The aforementioned radio frequency signal phase-stable transmission device, wherein the client further includes: The radio frequency output and distribution module is configured to distribute the phase-locked radio frequency signal into multiple radio frequency outputs.

[0011] The aforementioned radio frequency signal phase-stable transmission device, wherein the client further includes: The monitoring and control interface module is configured to detect the error signal, the control voltage, and the lock-in state parameter, wherein the lock-in state parameter is used to characterize the lock-in state between the pulsed laser synchronization signal and the adjusted radio frequency signal.

[0012] A method for stable phase transmission of radio frequency signals, comprising the following steps: Acquire the pulsed laser synchronization signal distributed by the optical reference source and the radio frequency synchronization signal distributed by the radio frequency reference source; wherein the optical reference source and the radio frequency reference source are in a synchronized state; Based on the voltage-controlled phase shifter, the radio frequency synchronization signal is adjusted to obtain the adjusted radio frequency signal; Based on the phase detector, an error signal is obtained according to the pulsed laser synchronization signal and the adjusted radio frequency signal; The control voltage is obtained based on the error signal, and the voltage-controlled phase shifter is controlled based on the control voltage to adjust the radio frequency synchronization signal and output the phase-locked radio frequency signal.

[0013] In the radio frequency signal phase-stable transmission method, the error signal is a signal representing the change in phase difference between the pulsed laser synchronization signal and the adjusted radio frequency signal, and the control voltage is determined based on the amplitude and trend of the error signal.

[0014] A computer device includes a memory and a processor, the memory storing a computer program, wherein the processor executes the computer program to implement the steps of the radio frequency signal phase-stable transmission method as described in any of the above claims.

[0015] A computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of the radio frequency signal phase-stable transmission method as described in any of the preceding claims.

[0016] Beneficial effects: Even if there is phase drift during the transmission of the radio frequency signal, the drift will be reflected in the error signal. Through the negative feedback control of the controller, the phase-locked radio frequency signal can be obtained, and the phase-locked radio frequency signal is phase-synchronized with the pulsed laser synchronization signal. Attached Figure Description

[0017] Figure 1 This is a functional principle block diagram of the device for stable phase transmission of radio frequency signals in an embodiment of the present invention.

[0018] Figure 2 This is a flowchart of the radio frequency signal phase-stable transmission method in an embodiment of the present invention. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer and more explicit, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0020] Please see Figure 1 This invention provides some embodiments of a device for stable phase transmission of radio frequency signals.

[0021] like Figure 1 As shown, the radio frequency signal phase-stable transmission apparatus of the present invention includes: The reference source includes an optical reference source and an radio frequency (RF) reference source, wherein the optical reference source and the RF reference source are in a synchronized state, the optical reference source is configured to distribute a pulsed laser synchronization signal, and the RF reference source is configured to distribute an RF synchronization signal. At least one client includes a voltage-controlled phase shifter, a phase detector, and a controller. The voltage-controlled phase shifter is configured to adjust the radio frequency synchronization signal to obtain an adjusted radio frequency signal. The phase detector is configured to obtain an error signal based on the pulsed laser synchronization signal and the adjusted radio frequency signal. The controller is configured to obtain a control voltage based on the error signal and control the voltage-controlled phase shifter based on the control voltage, so that the voltage-controlled phase shifter adjusts the radio frequency synchronization signal to output a phase-locked radio frequency signal.

[0022] Specifically, there can be multiple clients, each corresponding to the same reference source. The distance between the reference source and the clients can be on the order of kilometers. The reference source is configured with a phase-locked loop (PLL) to synchronize the optical and radio frequency (RF) reference sources. When the optical and RF reference sources are synchronized, the repetition frequencies of the RF synchronization signal distributed by the RF reference source and the pulsed laser synchronization signal distributed by the optical reference source satisfy an equal-frequency or integer multiple relationship. The optical and RF reference sources can maintain phase synchronization through the PLL.

[0023] An optical reference source is connected to a phase detector, an RF reference source is connected to a voltage-controlled phase shifter (VCS), and the VCS is connected to the phase detector. A controller is connected to both the phase detector and the VCS. The optical reference source distributes a pulsed laser synchronization signal to the phase detector, and the RF reference source distributes an RF synchronization signal to the VCS. The VCS adjusts the phase of the RF synchronization signal to obtain a regulated RF signal. The VCS is a voltage-controlled phase shifter, and the phase of its output signal is continuously adjustable with the control voltage, used for fine adjustment of the phase of the client's RF signal. The client also includes a power divider (or RF distribution unit), which is connected to the output of the VCS. The power divider splits the regulated RF signal into two paths: a first output port connected to the phase detector, and a second output port connected to a terminal, such as a low-level RF user equipment or a beam testing system. The phase detector has an optical port and an RF port. The pulsed laser synchronization signal enters the phase detector through the optical port, and the regulated RF signal enters the phase detector through the RF port. The phase detector obtains an error signal based on the pulsed laser synchronization signal and the regulated RF signal. This error signal represents the change in the phase difference between the pulsed laser synchronization signal and the regulated RF signal. The controller determines the control voltage based on the error signal and controls the voltage-controlled phase shifter accordingly. This allows the voltage-controlled phase shifter to adjust the phase of the RF synchronization signal and output a phase-locked RF signal. The control voltage is determined based on the amplitude and trend of the error signal. The amplitude of the error signal reflects the magnitude of the phase deviation between the pulsed laser synchronization signal and the regulated RF signal, while the trend reflects the trend of the phase difference change between them. Through negative feedback control, the error signal is brought close to zero, thus achieving phase locking of the RF signal to the pulsed laser synchronization signal. The controller employs a PID (Proportional Integral Derivative) controller, implementing a proportional-integral-derivative control algorithm to generate the control voltage driving the voltage-controlled phase shifter.

[0024] Even if there is phase drift during the transmission of the radio frequency signal, the drift will be reflected in the error signal. Through the negative feedback control of the controller, the phase-locked radio frequency signal can be obtained, and the phase-locked radio frequency signal is phase-synchronized with the pulsed laser synchronization signal.

[0025] In a preferred implementation of this invention, such as Figure 1 As shown, the radio frequency reference source is a radio frequency master oscillator, which is connected to the voltage-controlled phase shifter through a radio frequency transmission link.

[0026] Specifically, the RF reference source uses an RF master oscillator, for example, a 1.3 GHz RF master oscillator. The RF synchronization signal of the RF reference source is transmitted to the client via an RF transmission link and serves as the source of the RF signal to be phase-locked.

[0027] In a preferred implementation of this invention, such as Figure 1 As shown, the optical reference source is a reference laser, which is connected to the phase detector via a phase-stable fiber optic link.

[0028] Specifically, the optical reference source uses a reference laser, and the pulsed laser synchronization signal of the optical reference source is transmitted to the phase detector through a phase-stable fiber optic link.

[0029] In a preferred embodiment of the present invention, the phase detector can be a conventional electronic phase detector (requiring front-end photoelectric conversion) or an optical microwave phase detector. For example, the phase detector includes: An electro-optic phase modulation unit is configured to cause the pulsed laser synchronization signal and the adjusted radio frequency signal to undergo phase-dependent electro-optic phase modulation. A balance detector is configured to output an error signal characterizing the relative phase deviation between the pulsed laser synchronization signal and the radio frequency signal.

[0030] Specifically, the electro-optic phase interaction unit is connected to the optical port, the radio frequency (RF) port, and the balance detector. The pulsed laser synchronization signal input from the optical port enters the electro-optic phase interaction unit, where it undergoes phase correlation with the adjusted RF signal input from the RF port within the optical domain, generating an optical signal carrying the relative phase information of both signals. The balance detector performs balance detection on the optical signal and outputs an error signal characterizing the relative phase deviation between the pulsed laser synchronization signal and the RF signal.

[0031] In a preferred embodiment of the present invention, the client further includes: The radio frequency output and distribution module is configured to distribute the phase-locked radio frequency signal into multiple radio frequency outputs.

[0032] Specifically, the phase-locked radio frequency (RF) signal is taken out from the second output port of the voltage-controlled phase shifter. The second output port of the voltage-controlled phase shifter can be equipped with a cascaded amplifier to take out the phase-locked RF signal. The second output port of the voltage-controlled phase shifter or the cascaded amplifier can also be equipped with an RF output and distribution module to distribute it into multiple RF outputs for use by low-level RF customers, beam current testing systems, etc.; it can also be further expanded into a terminal RF synchronization network through further distribution.

[0033] In a preferred embodiment of the present invention, the client further includes: The monitoring and control interface module is configured to detect the error signal, the control voltage, and the lock-in state parameter, wherein the lock-in state parameter is used to characterize the lock-in state between the pulsed laser synchronization signal and the adjusted radio frequency signal.

[0034] Specifically, it collects and monitors key parameters such as error signals, control voltage, and lockout status; it can be remotely configured and displayed via FPGA (Field Programmable Gate Array) / MCU (Micro Controller Unit), and communicate with a host computer or control system.

[0035] Compared with existing radio frequency synchronization signal distribution methods, the present invention has the following significant advantages: (1) Active phase control, replacing passive temperature control This invention employs a closed-loop structure combining a phase detector and a voltage-controlled phase shifter to actively adjust the phase of the client's radio frequency signal and compensate for phase drift caused by coaxial cables in real time. It achieves high-precision synchronization without the need for large-volume temperature-controlled packaging of long-distance radio frequency cables, significantly reducing engineering complexity.

[0036] (2) Using a stable fiber laser link as the final reference The reference source is a pulsed laser transmitted via a phase-stable fiber optic link, which is widely used in devices such as FELs. Its jitter and drift can be made very small. The client's radio frequency is directly locked to this optical reference by a phase detector, realizing the structure of "radio frequency signal following the phase-stable laser" and giving full play to the advantages of the phase-stable fiber optic link.

[0037] (3) Avoid problems related to voltage-controlled oscillators (VCOs). Compared to the "phase detector and voltage-controlled oscillator" scheme, this invention uses a voltage-controlled phase shifter as the actuator to fine-tune the phase of the RF signal distributed from the RF reference source, instead of introducing a completely new voltage-controlled oscillator to generate RF; this avoids problems such as the start-up of the voltage-controlled oscillator and additional phase noise, and the system structure is simpler.

[0038] (4) Maintain consistency with the radio frequency reference source The client ultimately uses the RF signal originating from the RF reference source, but it undergoes a small phase correction via a voltage-controlled phase shifter after reaching the client; this facilitates compatibility with existing RF reference source distribution systems and allows for smooth upgrades in existing FELs and other large scientific facilities.

[0039] Based on the apparatus for stable phase transmission of radio frequency signals described in any of the above embodiments, the present invention also provides a preferred embodiment of a method for stable phase transmission of radio frequency signals.

[0040] like Figure 2 As shown, the radio frequency signal phase-stable transmission method of this embodiment includes the following steps: Step S100: Obtain the pulsed laser synchronization signal distributed by the optical reference source and the radio frequency synchronization signal distributed by the radio frequency reference source; wherein, the optical reference source and the radio frequency reference source are in a synchronized state; Step S200: Based on the voltage-controlled phase shifter, the radio frequency synchronization signal is adjusted to obtain the adjusted radio frequency signal; Step S300: Based on the phase detector, an error signal is obtained according to the pulsed laser synchronization signal and the adjusted radio frequency signal; Step S400: Obtain the control voltage based on the error signal, and control the voltage-controlled phase shifter based on the control voltage to adjust the radio frequency synchronization signal and output the phase-locked radio frequency signal.

[0041] Specifically, after acquiring the pulsed laser synchronization signal and the radio frequency (RF) synchronization signal, the client uses a voltage-controlled phase shifter (VDC) to adjust the RF synchronization signal and output the adjusted RF signal. A phase detector uses the pulsed laser synchronization signal and the adjusted RF signal to obtain an error signal. The client then uses this error signal to obtain a control voltage and controls the VDC to adjust the RF synchronization signal and output a phase-locked RF signal. The error signal is the change in phase difference between the pulsed laser synchronization signal and the adjusted RF signal, and the control voltage is determined based on the amplitude and trend of the error signal.

[0042] Step S300 specifically includes: Step S310: Based on the electro-optic phase interaction unit, the pulsed laser synchronization signal and the adjusted radio frequency signal undergo phase-related electro-optic phase modulation. Step S320: Based on the balance detector, output an error signal characterizing the relative phase deviation between the pulsed laser synchronization signal and the radio frequency signal.

[0043] Specifically, an electro-optic phase interaction unit is used to perform phase correlation processing between the pulsed laser synchronization signal and the radio frequency signal. An error signal is obtained based on the cross-correlation results using a balanced detector.

[0044] Based on the stable phase transmission method of radio frequency signals described in any of the above embodiments, the present invention also provides an embodiment of a computer device.

[0045] The computer device of the present invention includes a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the steps of the radio frequency signal phase-stable transmission method as described in any of the above embodiments.

[0046] Based on the radio frequency signal phase-stable transmission method described in any of the above embodiments, the present invention also provides an embodiment of a computer-readable storage medium.

[0047] The present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the radio frequency signal phase-stable transmission method as described in any of the above embodiments.

[0048] It should be understood that the application of the present invention is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A device for stable phase transmission of radio frequency signals, characterized in that, include: The reference source includes an optical reference source and an radio frequency (RF) reference source, wherein the optical reference source and the RF reference source are in a synchronized state, the optical reference source is configured to distribute a pulsed laser synchronization signal, and the RF reference source is configured to distribute an RF synchronization signal. At least one client includes a voltage-controlled phase shifter, a phase detector, and a controller. The voltage-controlled phase shifter is configured to adjust the radio frequency synchronization signal to obtain an adjusted radio frequency signal. The phase detector is configured to obtain an error signal based on the pulsed laser synchronization signal and the adjusted radio frequency signal. The controller is configured to obtain a control voltage based on the error signal and control the voltage-controlled phase shifter based on the control voltage, so that the voltage-controlled phase shifter adjusts the radio frequency synchronization signal to output a phase-locked radio frequency signal.

2. The apparatus for stable phase transmission of radio frequency signals according to claim 1, characterized in that, The radio frequency reference source is a radio frequency master oscillator, which is connected to the voltage-controlled phase shifter through a radio frequency transmission link.

3. The apparatus for stable phase transmission of radio frequency signals according to claim 1, characterized in that, The optical reference source is a reference laser, which is connected to the phase detector via a phase-stable fiber optic link.

4. The apparatus for stable phase transmission of radio frequency signals according to claim 1, characterized in that, The phase detector includes: An electro-optic phase modulation unit is configured to cause the pulsed laser synchronization signal and the adjusted radio frequency signal to undergo phase-dependent electro-optic phase modulation. A balance detector is configured to output an error signal characterizing the relative phase deviation between the pulsed laser synchronization signal and the radio frequency signal.

5. The apparatus for stable phase transmission of radio frequency signals according to any one of claims 1 to 4, characterized in that, The client also includes: The radio frequency output and distribution module is configured to distribute the phase-locked radio frequency signal into multiple radio frequency outputs.

6. The apparatus for stable phase transmission of radio frequency signals according to any one of claims 1 to 4, characterized in that, The client also includes: The monitoring and control interface module is configured to detect the error signal, the control voltage, and the lock-in state parameter, wherein the lock-in state parameter is used to characterize the lock-in state between the pulsed laser synchronization signal and the adjusted radio frequency signal.

7. A method for stable phase transmission of radio frequency signals, characterized in that, Including the following steps: Acquire the pulsed laser synchronization signal distributed by the optical reference source and the radio frequency synchronization signal distributed by the radio frequency reference source; wherein the optical reference source and the radio frequency reference source are in a synchronized state; Based on the voltage-controlled phase shifter, the radio frequency synchronization signal is adjusted to obtain the adjusted radio frequency signal; Based on the phase detector, an error signal is obtained according to the pulsed laser synchronization signal and the adjusted radio frequency signal; The control voltage is obtained based on the error signal, and the voltage-controlled phase shifter is controlled based on the control voltage to adjust the radio frequency synchronization signal and output the phase-locked radio frequency signal.

8. The method for stable phase transmission of radio frequency signals according to claim 7, characterized in that, The error signal is the signal of the phase difference change between the pulsed laser synchronization signal and the adjusted radio frequency signal, and the control voltage is determined according to the amplitude and trend of the error signal.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the radio frequency signal phase-stable transmission method according to any one of claims 7 to 8.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of the radio frequency signal phase-stable transmission method according to any one of claims 7 to 8.

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