Accelerator low level control system and method thereof

Abstract

The invention provides an accelerator low-level control system and method, and relates to the technical field of accelerators. A shared reference source synchronously drives a first signal generation unit and a second signal generation unit, so that a local oscillator signal and an intermediate frequency signal naturally have a phase coherence relationship; the risks of phase inconsistency and noise superposition introduced by multi-unit independent phase locking are reduced from the source; meanwhile, by carrying out coupling sampling on the radio frequency signal and generating digital in-phase data and digital orthogonal data, vectorization measurement on the amplitude and the phase of the radio frequency signal is realized, so that the processing module can generate a compensation instruction in real time based on a calibration error and adjust the amplitude and / or the phase of a local oscillator signal and the amplitude and / or the phase of an intermediate frequency signal on line; therefore, a closed-loop calibration and compensation mechanism is formed, the phase stability, the amplitude stability and the signal purity of radio frequency output are remarkably improved, and the repeatability and the reliability of long-term operation of the system are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of accelerators, in particular to an accelerator low-level control system and a method thereof. BACKGROUND

[0002] A particle accelerator includes a synchrotron radiation source, a free electron laser device, and a medical linear accelerator. During operation, the particle accelerator usually needs to perform ultra-high precision amplitude and phase control on the radio frequency signal of the acceleration cavity to ensure strict synchronization of the acceleration electric field and the particle beam in time and phase.

[0003] A conventional accelerator low-level radio frequency control system is usually implemented by splicing multiple independent phase-locked and discrete radio frequency units. Although the local oscillator and the intermediate frequency are homologous references, phase noise and phase error are still superimposed due to differences in the respective phase-locked loops and links, making it difficult to maintain phase coherence from the hardware level in the long term. At the same time, the temperature drift, time drift, and aging of analog devices such as mixers, amplifiers, and filters will introduce slow amplitude and phase drifts, and the system lacks built-in self-test sampling and closed-loop calibration capabilities. Calibration often relies on external instruments or manual offline processes, and compensation parameters are not updated in a timely manner, making it difficult to achieve long-term high-precision amplitude and phase stable control. SUMMARY

[0004] The technical problem to be solved by the present application is to provide an accelerator low-level control system and a method thereof to overcome the problems of phase synchronization difficulty caused by multiple independent phase-locked units, amplitude and phase instability caused by link drift, and long-term high-precision control difficulty caused by calibration dependence on offline or manual processes.

[0005] In a first aspect, the present application provides an accelerator low-level control system, comprising: a signal synthesis module including a first signal generation unit, a second signal generation unit, and a mixing unit driven by a shared reference source; The first signal generation unit is configured to generate a local oscillator signal based on a reference signal output by the shared reference source. The second signal generation unit is configured to generate an intermediate frequency signal based on the reference signal, and the local oscillator signal and the intermediate frequency signal are phase coherent. The mixing unit is configured to mix the local oscillator signal and the intermediate frequency signal to generate a radio frequency signal for use by an accelerator; a sampling module configured to couple a sampling signal from the radio frequency signal and generate a quadrature demodulation digital signal based on the sampling signal; wherein the quadrature demodulation digital signal includes digital in-phase data and digital quadrature data; The processing module is configured to calculate a calibration error according to the quadrature demodulation digital signal, and generate a compensation instruction according to the calibration error, so that the first signal generation unit adjusts the amplitude and / or phase of the output local oscillator signal in response to the compensation instruction, and the second signal generation unit adjusts the amplitude and / or phase of the output intermediate frequency signal in response to the compensation instruction; wherein the calibration error includes an amplitude error and a phase error.

[0006] In one of the embodiments, the system further comprises: The driving module is configured to perform power amplification on the radio frequency signal output by the mixing unit, and output the radio frequency signal to the accelerator. The sampling module is configured to couple a sampling signal from the power-amplified radio frequency signal.

[0007] In one of the embodiments, the first signal generation unit comprises: The frequency divider is configured to divide the reference signal output by the shared reference source to generate a divided reference signal. The first mixer is configured to mix the divided reference signal and the reference signal to output a first target signal with a target frequency. The first filter is configured to perform filtering processing on the first target signal to generate a local oscillator signal.

[0008] In one of the embodiments, the signal synthesis module further comprises: The phase-locked loop is configured to generate a locked local oscillator signal based on the filtered signal, and perform phase noise purification on the local oscillator signal.

[0009] In one of the embodiments, the second signal generation unit comprises: The signal generator is configured to generate a second target signal based on the reference signal. The second filter is configured to perform filtering processing on the second target signal to generate a radio frequency signal and output the radio frequency signal to the accelerator.

[0010] In one of the embodiments, the mixing unit comprises: The second mixer is configured to mix the local oscillator signal and the intermediate frequency signal. The third filter is configured to perform filtering processing on the radio frequency signal output by the second mixer and output the radio frequency signal to the accelerator.

[0011] In one of the embodiments, the sampling module comprises: The coupler is configured to couple a sampling signal from the power-amplified radio frequency signal. a quadrature down-mixer, configured to perform quadrature down-conversion on the sampling signal to generate an in-phase I analog signal and a quadrature Q analog signal; an analog-to-digital converter, configured to sample and analog-to-digital convert the in-phase I analog signal and the quadrature Q analog signal to generate a quadrature demodulation digital signal. In one of the embodiments, the sampling module further comprises: a switch matrix, configured to establish a controllable conduction path between the coupler and the quadrature down-mixer to selectively route the sampling signal coupled by the coupler to the quadrature down-mixer.

[0012] In one of the embodiments, the sampling module further comprises: a fourth filter, configured to filter the in-phase I analog signal to generate an in-phase I analog signal; a fifth filter, configured to filter the quadrature Q analog signal to generate a quadrature Q analog signal.

[0013] In one of the embodiments, the system further comprises: a host computer, configured to acquire and display the monitoring data output by the processing module, and configured to issue control parameters to the system to realize monitoring and control.

[0014] In one of the embodiments, the processing module calculates a calibration error according to the quadrature demodulation digital signal, and generates a compensation instruction according to the calibration error, comprising: in response to a calibration trigger signal, acquiring a calibration channel sequence to be calibrated and a corresponding target parameter; wherein each calibration channel corresponds to a selectable signal path in the system; switching to the corresponding calibration channel in sequence according to the calibration channel sequence; for the current calibration channel, collecting quadrature demodulation digital signals of a preset period, the quadrature demodulation digital signals comprising digital in-phase data and digital quadrature data; calculating the amplitude value and the phase value of the current calibration channel based on the quadrature demodulation digital signals, comparing the calculated amplitude value and the phase value with the target parameter to obtain a calibration error, calculating a compensation value according to the calibration error, and generating a compensation instruction based on the compensation value, so that the first signal generation unit and the second signal generation unit update the control parameters in response to the compensation instruction; performing calibration accuracy verification on the current calibration channel under the updated control parameters, and when the calibration accuracy meets a preset condition, recording the compensation parameter corresponding to the current calibration channel to a compensation table and storing it to a memory, until all calibration channels in the calibration channel sequence are completed.

[0015] In a second aspect, the application further provides an accelerator low-level control method, comprising: obtaining a reference signal output by a shared reference source; generating a local oscillator signal based on the reference signal by using a first signal generation unit, and generating an intermediate frequency signal based on the reference signal by using a second signal generation unit, wherein the local oscillator signal and the intermediate frequency signal are phase coherent; inputting the local oscillator signal and the intermediate frequency signal into a mixing unit for mixing to generate a radio frequency signal for use by an accelerator; coupling a sampling signal from the radio frequency signal by using a sampling module, and performing quadrature demodulation based on the sampling signal to generate a quadrature demodulation digital signal, wherein the quadrature demodulation digital signal comprises digital in-phase data and digital quadrature data; calculating a calibration error based on the quadrature demodulation digital signal by using a processing module, and generating a compensation instruction according to the calibration error, so that the first signal generation unit adjusts the amplitude and / or phase of the output local oscillator signal in response to the compensation instruction, and the second signal generation unit adjusts the amplitude and / or phase of the output intermediate frequency signal in response to the compensation instruction, wherein the calibration error comprises an amplitude error and a phase error.

[0016] The accelerator low-level control system and method described above have at least the following advantages: The application synchronously drives the first signal generation unit and the second signal generation unit by the shared reference source, so that the local oscillator signal and the intermediate frequency signal naturally have a phase coherent relationship, thereby reducing the risk of phase inconsistency and noise superposition introduced by independent phase locking of multiple units from the source. At the same time, by coupling and sampling the radio frequency signal to generate digital in-phase data and digital quadrature data, vector measurement of the amplitude and phase of the radio frequency signal is realized, so that the processing module can generate a compensation instruction in real time based on the calibration error, and adjust the amplitude and / or phase of the local oscillator signal and the amplitude and / or phase of the intermediate frequency signal online, thereby forming a closed-loop calibration and compensation mechanism, significantly improving the phase stability, amplitude stability and signal purity of the radio frequency output, and improving the repeatability and reliability of long-term operation of the system. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is a structural block diagram of an accelerator low-level control system in one embodiment; Figure 2 is a structural block diagram of an accelerator low-level control system in another embodiment; Figure 3 is a structural block diagram of a first signal generation unit in one embodiment; Figure 4 is a structural block diagram of a first signal generation unit in another embodiment; Figure 5This is a structural block diagram of the second signal generation unit in one embodiment; Figure 6 This is a structural block diagram of the hybrid unit in one embodiment; Figure 7 Here is a structural block diagram of the sampling module in one embodiment; Figure 8 This is another structural block diagram of the sampling module in one embodiment; Figure 9 Here is a structural block diagram of the sampling module in another embodiment; Figure 10 This is a flowchart illustrating the calibration steps of the processing module in one embodiment. Figure 11 This is a flowchart illustrating a low-level radio frequency control method for an accelerator in one embodiment. Detailed Implementation

[0018] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings. Preferred embodiments of this application are shown in the drawings. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of this application.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0020] When using the terms “including,” “having,” and “comprising” as described herein, another component may be added unless explicitly qualifying terms such as “only,” “consisting of,” etc. are used. Unless otherwise stated, singular terms may include plural forms and should not be construed as having a quantity of one.

[0021] It should be understood that although the terms “first,” “second,” etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are used only to distinguish one element from another. For example, without departing from the scope of this application, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element.

[0022] In this application, unless otherwise expressly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a direct connection or an indirect connection through an intermediate medium, or they can refer to the internal connection of two elements or the interaction between two elements. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0023] Please see Figure 1 In one embodiment, this application provides a low-level control system for an accelerator, including: a signal synthesis module, a sampling module, and a processing module.

[0024] The signal synthesis module includes a first signal generation unit, a second signal generation unit, and a mixing unit driven by a shared reference source. The first signal generation unit generates a local oscillator signal based on a reference signal output from the shared reference source; the second signal generation unit generates an intermediate frequency (IF) signal based on the reference signal, wherein the local oscillator signal and the IF signal are in phase; and the mixing unit mixes the local oscillator signal and the IF signal to generate a radio frequency (RF) signal for use by the accelerator.

[0025] Please see Figure 3 Optionally, the first signal generation unit includes a frequency divider, a first mixer, and a first filter.

[0026] A frequency divider is used to divide the reference signal output from a shared reference source to generate a frequency-divided reference signal.

[0027] The first mixer is used to mix the frequency division reference signal and the reference signal to output a first target signal with the target frequency.

[0028] The first filter is used to filter the first target signal to generate a local oscillator signal.

[0029] Please see Figure 5 Optionally, the second signal generation unit includes a signal generator and a second filter.

[0030] A signal generator used to generate a second target signal based on a reference signal.

[0031] The second filter is used to filter the second target signal to generate a radio frequency signal and output it to the accelerator.

[0032] Please see Figure 6 Optionally, the mixing unit includes a second mixer and a third filter.

[0033] The second mixer is used to mix the local oscillator signal and the intermediate frequency signal.

[0034] The third filter filters the radio frequency signal output from the second mixer before outputting it to the accelerator.

[0035] Specifically, a shared reference source is used to output a stable reference signal, which serves as the system's unified frequency and phase reference and is provided to the frequency divider, the first mixer, and the signal generator, respectively.

[0036] The frequency divider receives the reference signal output from the shared reference source, performs frequency division processing on it, generates a frequency-divided reference signal, and outputs it to the first mixer.

[0037] The first mixer simultaneously receives both a reference signal and a frequency-divided reference signal, performs mixing operations on the two signals to obtain an output signal containing multiple frequency-converted components, and selects the component with the target frequency as the local oscillator signal for output. Using this scheme, since both inputs to the first mixer originate from the same shared reference source, the generated local oscillator signal maintains a definite phase correlation with the reference signal, thus providing a basis for subsequent coherent synthesis.

[0038] The signal generator uses a reference signal as the synthesis reference and generates an intermediate frequency (IF) waveform according to preset frequency and phase control parameters, ensuring that the frequency and phase of the IF signal are also constrained by the shared reference source. Since both the first mixer and the signal generator are driven by the same shared reference source, the local oscillator signal and the IF signal are established on the same phase reference. Therefore, the phase difference between the local oscillator signal and the IF signal presents a predictable and repeatable deterministic relationship within the same reference system, thereby achieving phase coherence.

[0039] The second mixer receives the local oscillator signal and the intermediate frequency signal, performs a mixing operation on the two signals to obtain an output signal containing multiple frequency conversion components, and selects the component with the target frequency as the radio frequency signal that meets the requirements of the accelerator. Since the local oscillator signal and the intermediate frequency signal are phase-coherent, the phase of the radio frequency signal generated by the mixing is also determined by the phase relationship between the two, thus possessing the characteristics of phase controllability and stability.

[0040] Furthermore, in addition to the target frequency component, the signal output by the mixer usually also contains a certain degree of non-ideal components. Therefore, this application employs a first filter to filter the output signal of the first mixer.

[0041] Optionally, the first filter includes a low-pass filter and / or a band-pass filter. The low-pass filter suppresses unwanted spectral components such as high-frequency spurious signals and quantization noise in the signal generator output, resulting in a cleaner signal spectrum entering the second mixer and reducing introduced parasitic frequencies and interference. The band-pass filter suppresses out-of-band noise and unwanted frequency components in the first mixer output, reducing local oscillator leakage and phase noise rise caused by out-of-band noise entering the mixing process, thereby improving the signal purity and phase stability of the mixed RF signal. Using the above scheme, through the coordinated configuration of the frequency divider, the first mixer, and the first filter, the first mixer obtains a more suitable locking reference, while simultaneously performing spectral cleansing on the intermediate frequency signal and local oscillator signal entering the second mixer. This reduces noise coupling and superposition during the mixing process, improving the signal purity and long-term stability of the RF output.

[0042] It should be noted that the structure and working principle of the second and third filters mentioned above are the same as those of the first filter, and will not be repeated here to save space.

[0043] The sampling module is used to couple a sampled signal from the radio frequency signal and generate a quadrature demodulated digital signal based on the sampled signal; wherein, the quadrature demodulated digital signal includes digital in-phase data and digital quadrature data.

[0044] Specifically, the sampling module couples and samples the radio frequency (RF) signal to obtain a sampled signal corresponding to the RF signal. It then performs quadrature demodulation and analog-to-digital conversion on this sampled signal to generate a quadrature demodulated digital signal, including digital in-phase data and digital quadrature data, to characterize the amplitude and phase information of the RF signal. It should be noted that the power of the coupled sampled signal is relatively low, used for subsequent measurements and calibrations without affecting the normal power supply of the accelerator to the main RF channel.

[0045] The processing module is used to calculate the calibration error based on the quadrature demodulated digital signal and generate a compensation command based on the calibration error, so that the first mixer adjusts the amplitude and / or phase of the output local oscillator signal in response to the compensation command, and the signal generator adjusts the amplitude and / or phase of the output intermediate frequency signal in response to the compensation command; wherein, the calibration error includes amplitude error and phase error.

[0046] Specifically, the processing module calculates the amplitude and phase of the current RF signal based on digital in-phase and digital quadrature data, and compares them with the target amplitude and phase to obtain the calibration error, which includes amplitude and phase errors. Further, the processing module calculates the compensation amount based on the calibration error and generates a compensation command, which is sent to the first mixer and the signal generator to update the amplitude and / or phase of the signal. Using the above scheme, this application can achieve closed-loop calibration and compensation of the RF output through a link of controllable local oscillator and intermediate frequency, mixing mapping, and RF output, thereby improving the amplitude and phase stability of the RF signal and enhancing the long-term reliability and repeatability of the system.

[0047] Please see Figure 2 Optionally, the above-mentioned accelerator low-level control system further includes a drive module.

[0048] The driver module is used to amplify the power of the RF signal output from the mixing unit and output it to the accelerator.

[0049] The sampling module is used to couple a sampled signal from the power-amplified radio frequency signal.

[0050] Specifically, the RF signal output by the hybrid unit is typically a low-power signal with limited driving capability, making it difficult to meet the requirements of accelerators. Power amplification via a drive module can boost the RF signal to the power level required by the accelerator, improving the driving capability to load impedance changes and enhancing system stability. Furthermore, the drive module may introduce gain and phase drift during actual operation. By setting a sampling module at the output of the drive module for coupled sampling, the back-end processing module can incorporate the amplitude and phase errors introduced by the drive module into the calibration error calculation. Compensation commands can then be used to adjust the amplitude and / or phase of the intermediate frequency signal output from the signal generator, thereby achieving closed-loop calibration and long-term stable control of the RF main link, improving the amplitude and phase stability of the RF output, and enhancing system reliability.

[0051] Optionally, the sampling module can also be set between the mixing unit and the driving module as needed. In this way, the sampled signal represents the original radio frequency signal output by the signal synthesis module. By analyzing it, the true error data of the signal synthesis module can be obtained.

[0052] For example, the driving module in this embodiment uses a solid-state amplifier. In other embodiments, users may also select other devices, such as vacuum tube amplifiers, according to project requirements. Please see Figure 4 Optionally, the signal synthesis module may also include a phase-locked loop.

[0053] A phase-locked loop (PLL) is connected between the first filter and the second mixer. It is used to generate a locked local oscillator signal based on the filtered signal and to perform phase noise reduction on the local oscillator signal.

[0054] Specifically, the phase-locked loop (PLL) establishes a locking relationship between the output signal generated by the internal oscillation unit and the filtered signal, ensuring that the frequency of the local oscillator signal output by the PLL is consistent with or maintains a preset proportional relationship with the filtered signal, and maintaining a stable phase relationship between the local oscillator signal and the filtered signal. Furthermore, during the locking process, the PLL suppresses short-term jitter and out-of-band noise in the input signal, reducing the phase noise of the output local oscillator signal, thereby achieving phase noise purification of the local oscillator signal.

[0055] Please see Figure 7 and Figure 8 Optionally, the sampling module includes: a coupler, an orthogonal downconverter mixer, and an analog-to-digital converter.

[0056] A coupler is used to couple a sampled signal from a power-amplified radio frequency signal.

[0057] A quadrature downconverter mixer is used to perform quadrature downconversion processing on the sampled signal to generate an in-phase I-channel analog signal and a quadrature Q-channel analog signal.

[0058] An analog-to-digital converter (ADC) is used to sample and convert in-phase I-channel analog signals and quadrature Q-channel analog signals to generate quadrature demodulated digital signals.

[0059] Optionally, the sampling module may also include a fourth filter and a fifth filter.

[0060] The fourth filter is used to filter the in-phase I-channel analog signal to generate the in-phase I-channel analog signal.

[0061] The fifth filter is used to filter the quadrature Q-path analog signal to generate the quadrature Q-path analog signal.

[0062] Specifically, the quadrature downconverter mixer includes a local oscillator signal input interface, a 90° phase shifter, an I-channel mixer, and a Q-channel mixer; the fourth and fifth filters are both low-pass filters. The local oscillator signal input interface receives the local oscillator signal output from the phase-locked loop; the 90° phase shifter divides the local oscillator signal into an I-channel local oscillator signal and a Q-channel local oscillator signal, each 90° out of phase; the I-channel mixer mixes the sampled signal with the I-channel local oscillator signal; the Q-channel mixer mixes the sampled signal with the Q-channel local oscillator signal; the fourth filter performs low-pass filtering on the signal after mixing the sampled signal with the I-channel local oscillator signal to suppress high-frequency mixing products, obtaining an in-phase I-channel analog signal; the fifth filter performs low-pass filtering on the signal after mixing the sampled signal with the Q-channel local oscillator signal, obtaining a quadrature Q-channel analog signal.

[0063] Furthermore, analog-to-digital converters include I-channel converters ( Figure 8 The I-channel ADC and Q-channel converter shown are shown. Figure 8 The Q-channel ADC shown is used to sample and convert the in-phase I-channel analog signal to digital, outputting in-phase digital data; the Q-channel ADC is used to sample and convert the quadrature Q-channel analog signal to digital, outputting quadrature digital data to generate quadrature demodulated digital signals.

[0064] Please see Figure 9 Optionally, the sampling module may also include a switch matrix.

[0065] A switching matrix is ​​used to establish a controllable conduction path between the coupler and the quadrature downconverter mixer to selectively route the sampled signal coupled by the coupler to the quadrature downconverter mixer.

[0066] Specifically, a switch matrix is ​​a set of controllable multi-input, single-output, or multi-input, multi-output routing networks, which can typically be composed of controllable RF switches and multiplexers. Its function is to selectively connect the sampled signals from different sampling points or different coupler ports to the input of the subsequent quadrature downconverter mixer according to the control instructions.

[0067] For example, the processing module sends a channel selection command to the switch matrix. The switch matrix turns on the switch path corresponding to the target sampling signal according to the channel selection command and turns off the other paths, so that the target sampling signal is sent to the quadrature downconverter mixer for quadrature downconversion and subsequent analog-to-digital conversion, thereby generating a quadrature demodulated digital signal corresponding to the currently selected channel.

[0068] By adopting the above scheme and setting up a switch matrix, the system can selectively measure and calibrate the sampling signals of different sampling points or different channels without interrupting the power supply to the accelerator from the main RF channel. At the same time, the switch matrix isolates the unselected channels, which also reduces crosstalk and impedance coupling caused by the parallel connection of multiple sampling signals and improves the calibration accuracy of the quadrature demodulated digital signal. Optionally, the aforementioned accelerator low-level control system further includes a host computer.

[0069] The host computer is used to acquire and display the monitoring data output by the processing module, and to send control parameters to the system to achieve monitoring and control.

[0070] Specifically, the monitoring data includes digital I / Q data, amplitude and phase errors, phase-locked loop status, alarm event logs, etc. Control parameters include target amplitude and phase setpoints, closed-loop control parameters, intermediate frequency of the signal generator, amplitude and phase parameters of the signal generator, switch matrix channel selection, alarm thresholds, etc.

[0071] The host computer can acquire and display key monitoring data in real time during system operation, and also provides parameter distribution and threshold management capabilities, enabling the system to have visualized and maintainable monitoring capabilities, facilitating multi-channel calibration, closed-loop control start and stop, and abnormal alarm handling, thereby improving the reliability and engineering availability of system operation.

[0072] For example, the following describes the operation of the accelerator low-level control system of this application in conjunction with accelerator operation stability scenarios (such as continuous waves).

[0073] Large accelerators use multiple RF transmitters to simultaneously drive different high-frequency cavities, requiring strict phase synchronization between the RF signals of each cavity. Traditional independent source solutions, even using the same reference, require high amplitude and phase stability.

[0074] This application constructs a closed-loop chain for signal generation, sampling, feedback, and processing: A shared reference source outputs a 10MHz high-stability reference clock, driving the first mixer and signal generator to generate a phase-coherent 1GHz intermediate frequency (IF) signal and a 10GHz local oscillator (LO) signal. The IF and LO are up-converted by the second mixer to output an 11GHz radio frequency (RF) signal.

[0075] The RF signal is output to the accelerator through the main channel, and a small portion is routed to the quadrature downconverter mixer sequentially at 1ms intervals via the coupler of the sampling module. The quadrature downconverter mixer mixes the RF signal with the local oscillator to obtain the baseband I / Q analog signal, which is then digitized into an I / Q data stream by a dual-channel ADC (16-bit resolution).

[0076] The I / Q data output by the ADC is sent to the processing module (DSP), which runs a calibration algorithm to calculate the amplitude and phase error. The host computer displays the calibration results and sends control commands. The DSP generates compensation commands based on the error results and feeds them back to the system to adjust the amplitude and phase of the IF / LO signal and the amplitude and phase parameters of the radio frequency in real time.

[0077] Please see Figure 10 Optionally, the processing module calculates the calibration error based on the quadrature demodulated digital signal and generates a compensation instruction based on the calibration error, including: In response to the calibration trigger signal, the sequence of calibration channels to be calibrated and their corresponding target parameters are acquired; wherein each calibration channel corresponds to a selectable signal path in the system.

[0078] Switch to the corresponding calibration channel in sequence according to the calibration channel sequence.

[0079] For the current calibration channel, quadrature demodulated digital signals are acquired at preset intervals. The quadrature demodulated digital signals include digital in-phase data and digital quadrature data.

[0080] The amplitude and phase values ​​of the current calibration channel are calculated based on the quadrature demodulated digital signal. The calculated amplitude and phase values ​​are compared with the target parameters to obtain the calibration error. The compensation value is calculated based on the calibration error, and a compensation command is generated based on the compensation value so that the first signal generation unit and the second signal generation unit update the control parameters in response to the compensation command.

[0081] Under the updated control parameters, the calibration accuracy of the current calibration channel is verified. When the calibration accuracy meets the preset conditions, the compensation parameters corresponding to the current calibration channel are recorded to the compensation table and stored in the memory until all calibration channels in the calibration channel sequence are completed.

[0082] Specifically, the calibration trigger signal can be issued by the processing module or the host computer. This application sets up a fully automatic, online, timed calibration trigger mechanism, which can generate calibration trigger signals based on preset strategies. The preset strategies include time triggering, temperature triggering, or automatic command triggering to ensure long-term performance.

[0083] Furthermore, this application pre-establishes the correspondence between calibration channels and signal paths. Each calibration channel corresponds to a selectable signal path in the system, such as a gating state of a switch matrix, a coupling sampling point, or a signal link branch, so that different channels can obtain independent compensation parameters.

[0084] Upon receiving the calibration trigger signal, the processing module acquires the calibration channel sequence to be calibrated and its corresponding target parameters. The calibration channel sequence indicates the calibration order of the calibration channels, and the target parameters indicate the target amplitude and phase values ​​for each calibration channel. Subsequently, the processing module controls the switch matrix to sequentially switch to the corresponding calibration channels according to the calibration channel sequence, routing the sampling signals of the corresponding calibration channels to the quadrature downconverter mixer.

[0085] After the signal generator completes the control parameter update, the processing module performs calibration accuracy verification on the current calibration channel under the updated control parameters. Specifically, the processing module re-acquires the quadrature demodulated digital signal for a preset period and calculates the amplitude and phase values ​​to determine whether the deviation between the signal and the target parameters meets the preset calibration accuracy conditions. When the preset conditions are met, the compensation parameters corresponding to the current calibration channel are recorded in the compensation table and stored in the memory for subsequent operation or re-triggered calibration. When the preset conditions are not met, the compensation value can continue to be calculated and the control parameters updated until the preset conditions are met or the preset iteration limit is reached.

[0086] The processing module repeatedly executes the switching, acquisition, error calculation, compensation update, and accuracy verification process for each calibration channel in the calibration channel sequence until all calibration channels in the sequence are calibrated, thereby forming a multi-channel compensation table and achieving consistent calibration across multiple channels. Through this fully automated online calibration mechanism, amplitude and phase drift of different channels can be continuously suppressed during long-term operation, improving the long-term stability of multi-channel RF output and reducing reliance on external instruments and manual maintenance.

[0087] Based on the same inventive concept, this application also provides a method for controlling low-level radio frequency of an accelerator. This method is applicable to the above-mentioned low-level radio frequency control system for an accelerator. The solution provided by this method is similar to the solution described in the above-mentioned system. Therefore, the specific limitations of one or more device embodiments provided below can be found in the system limitations above, and will not be repeated here.

[0088] Please see Figure 11 This application also provides a method for controlling low-level radio frequency in an accelerator, comprising: Step 1102: Obtain the reference signal output by the shared reference source.

[0089] Step 1104: The first signal generation unit generates a local oscillator signal based on the reference signal, and the second signal generation unit generates an intermediate frequency signal based on the reference signal, wherein the local oscillator signal and the intermediate frequency signal are phase-coherent.

[0090] Step 1106: The local oscillator signal and the intermediate frequency signal are mixed in the mixing unit to generate a radio frequency signal for use by the accelerator.

[0091] Step 1108: A sampling module is used to couple a sampling signal from the radio frequency signal, and quadrature demodulation is performed on the sampling signal to generate a quadrature demodulated digital signal; wherein, the quadrature demodulated digital signal includes digital in-phase data and digital quadrature data.

[0092] Step 1110: The processing module calculates the calibration error based on the quadrature demodulated digital signal and generates a compensation command according to the calibration error, so that the first signal generation unit adjusts the amplitude and / or phase of the output local oscillator signal in response to the compensation command, and the second signal generation unit adjusts the amplitude and / or phase of the output intermediate frequency signal in response to the compensation command; wherein, the calibration error includes amplitude error and phase error.

[0093] The aforementioned low-level RF control method for accelerators synchronously drives the first and second signal generation units using a shared reference source, ensuring that the local oscillator signal and the intermediate frequency signal naturally have a phase coherence relationship. This reduces the risk of phase inconsistency and noise superposition introduced by independent phase-locked loops of multiple units from the source. Simultaneously, by coupling and sampling the RF signal and generating digital in-phase and digital quadrature data, vectorized measurement of the RF signal amplitude and phase is achieved. This enables the processing module to generate compensation commands in real time based on calibration errors and adjust the amplitude and / or phase of the local oscillator signal and the amplitude and / or phase of the intermediate frequency signal online, thereby forming a closed-loop calibration and compensation mechanism. This significantly improves the phase stability, amplitude stability, and signal purity of the RF output, and enhances the repeatability and reliability of the system during long-term operation.

[0094] Please note that the above embodiments are for illustrative purposes only and do not imply any limitation on this application.

[0095] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0096] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0097] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A low-level radio frequency control system for an accelerator, characterized in that, include: The signal synthesis module includes a first signal generation unit, a second signal generation unit, and a mixing unit, all driven by a shared reference source. The first signal generation unit is used to generate a local oscillator signal based on the reference signal output by the shared reference source; the second signal generation unit is used to generate an intermediate frequency signal based on the reference signal, wherein the local oscillator signal and the intermediate frequency signal are phase-coherent; and the mixing unit is used to mix the local oscillator signal and the intermediate frequency signal to generate a radio frequency signal for use by the accelerator. A sampling module is used to couple a sampled signal from the radio frequency signal and generate a quadrature demodulated digital signal based on the sampled signal; wherein the quadrature demodulated digital signal includes digital in-phase data and digital quadrature data; The processing module is configured to calculate the calibration error based on the quadrature demodulated digital signal, and generate a compensation instruction based on the calibration error, so that the first signal generation unit adjusts the amplitude and / or phase of the output local oscillator signal in response to the compensation instruction, and the second signal generation unit adjusts the amplitude and / or phase of the output intermediate frequency signal in response to the compensation instruction; wherein the calibration error includes amplitude error and phase error.

2. The system according to claim 1, characterized in that, The system also includes: The driving module is used to amplify the power of the radio frequency signal output by the mixing unit and output it to the accelerator; The sampling module is used to couple a sampled signal from the power-amplified radio frequency signal.

3. The system according to claim 2, characterized in that, The first signal generation unit includes: A frequency divider is used to divide the reference signal output from the shared reference source to generate a frequency-divided reference signal. A first mixer is used to mix the frequency division reference signal and the reference signal to output a first target signal having a target frequency; The first filter is used to filter the first target signal to generate a local oscillator signal.

4. The system according to claim 3, characterized in that, The first signal generation unit further includes: A phase-locked loop (PLL) is used to generate a locked local oscillator signal based on a filtered signal and to perform phase noise purification on the local oscillator signal.

5. The system according to claim 2, characterized in that, The second signal generation unit includes: A signal generator is used to generate a second target signal based on the reference signal; The second filter is used to filter the second target signal to generate a radio frequency signal and output it to the accelerator.

6. The system according to claim 2, characterized in that, The mixing unit includes: The second mixer is used to mix the local oscillator signal and the intermediate frequency signal; The third filter filters the radio frequency signal output from the second mixer before outputting it to the accelerator.

7. The system according to claim 2, characterized in that, The sampling module includes: A coupler is used to couple a sampled signal from a power-amplified radio frequency signal. A quadrature downconversion mixer is used to perform quadrature downconversion processing on the sampled signal to generate an in-phase I-channel analog signal and a quadrature Q-channel analog signal; An analog-to-digital converter is used to sample and convert the in-phase I-channel analog signal and the quadrature Q-channel analog signal to generate a quadrature demodulated digital signal.

8. The system according to claim 7, characterized in that, The sampling module further includes: A switching matrix is ​​used to establish a controllable conduction path between the coupler and the quadrature downconverter mixer to selectively route the sampled signal coupled by the coupler to the quadrature downconverter mixer.

9. The system according to claim 7, characterized in that, The sampling module further includes: The fourth filter is used to filter the in-phase I-channel analog signal to generate the in-phase I-channel analog signal; The fifth filter is used to filter the quadrature Q-path analog signal to generate the quadrature Q-path analog signal.

10. The system according to claim 2, characterized in that, The system also includes: The host computer is used to acquire and display the monitoring data output by the processing module, and to send control parameters to the system to achieve monitoring and control.

11. The system according to claim 2, characterized in that: The processing module calculates the calibration error based on the quadrature demodulated digital signal and generates a compensation instruction based on the calibration error, including: In response to a calibration trigger signal, the sequence of calibration channels to be calibrated and their corresponding target parameters are acquired; wherein each calibration channel corresponds to a selectable signal path in the system; Switch to the corresponding calibration channel in sequence according to the calibration channel sequence; For the current calibration channel, quadrature demodulated digital signals are acquired at a preset period, including digital in-phase data and digital quadrature data; The amplitude and phase values ​​of the current calibration channel are calculated based on the quadrature demodulated digital signal, and the calculated amplitude and phase values ​​are compared with the target parameters to obtain the calibration error. A compensation value is calculated based on the calibration error, and a compensation command is generated based on the compensation value so that the first signal generation unit and the second signal generation unit update the control parameters in response to the compensation command. Under the updated control parameters, the calibration accuracy of the current calibration channel is verified. When the calibration accuracy meets the preset conditions, the compensation parameters corresponding to the current calibration channel are recorded in the compensation table and stored in the memory until all calibration channels in the calibration channel sequence are completed.

12. A method for low-level radio frequency control of an accelerator, characterized in that, include: Obtain the reference signal output from the shared reference source; A first signal generation unit generates a local oscillator signal based on the reference signal, and a second signal generation unit generates an intermediate frequency signal based on the reference signal, wherein the local oscillator signal and the intermediate frequency signal are phase-coherent. The local oscillator signal and the intermediate frequency signal are mixed in the mixing unit to generate a radio frequency signal for use by the accelerator. A sampling module is used to couple a sampling signal from the radio frequency signal, and quadrature demodulation is performed on the sampling signal to generate a quadrature demodulated digital signal; wherein, the quadrature demodulated digital signal includes digital in-phase data and digital quadrature data; The processing module calculates the calibration error based on the quadrature demodulated digital signal and generates a compensation command according to the calibration error, so that the first signal generation unit adjusts the amplitude and / or phase of the output local oscillator signal in response to the compensation command, and the second signal generation unit adjusts the amplitude and / or phase of the output intermediate frequency signal in response to the compensation command; wherein, the calibration error includes amplitude error and phase error.

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