Three-stage frequency conversion electron cyclotron radiation diagnosis system capable of adjusting diagnosis space overlapping degree

Abstract

The invention discloses a three-stage frequency conversion electron cyclotron radiation diagnosis system capable of adjusting a diagnosis space overlapping degree, and relates to the technical field of nuclear fusion plasma diagnosis. The system comprises an antenna used for receiving an electron cyclotron radiation signal of plasma; the primary mixer is used for generating a first intermediate frequency signal; the first-stage power divider is used for distributing the first intermediate frequency signal to a plurality of first parallel independent channels; a plurality of secondary mixers for generating a second intermediate frequency signal; the plurality of second-stage power dividers are used for distributing second intermediate frequency signals output by each second-stage frequency mixer in the plurality of second-stage frequency mixers to a plurality of second parallel independent channels; the plurality of third-stage frequency mixers are used for generating third intermediate frequency signals; and the plurality of detectors are used for converting the third intermediate-frequency signal into a direct-current voltage signal. According to the invention, the visual field overlapping degree of the diagnosis space is dynamically controlled, and the adaptability and practicability of the diagnosis system are improved.

Description

Technical Field

[0001] This invention relates to the field of nuclear fusion plasma diagnostic technology, specifically to a three-stage frequency conversion electron cyclotron radiation diagnostic system with adjustable diagnostic spatial overlap. Background Technology

[0002] In magnetically confined nuclear fusion plasma research, electron temperature fluctuations are a crucial factor leading to anomalous thermal transport. To reveal the evolution of turbulence, correlated electron cyclotron radiation (CECE) technology is widely used to measure the cross-correlation of temperature perturbation signals at multiple diagnostic locations, thereby extracting key physical parameters such as turbulence intensity changes.

[0003] Existing CECE systems typically employ a two-stage frequency conversion structure: the radio frequency signal is down-converted to an intermediate frequency (IF) by a first-stage local oscillator, and then further converted by a second-stage frequency converter before entering the final IF channel for detection and acquisition. This structure enables high-sensitivity detection of temperature fluctuation signals. However, in practical applications, when correlation analysis of the responses to the same physical disturbance at different diagnostic spatial locations is required, partial overlap of the diagnostic spatial fields of view between adjacent detection channels is necessary. This overlap depends on the proximity of the frequencies detected by the two channels. However, traditional structural solutions have the following problems:

[0004] If a fixed filter structure is used, the center frequency of each channel is not adjustable, resulting in a fixed overlap range of the diagnostic space, which cannot adapt to the changes in turbulence scale in different discharge stages or different regions.

[0005] If a YIG (yttrium iron garnet) tunable filter is used to achieve frequency adjustment, the problem of high cost will be encountered.

[0006] Therefore, existing technologies have significant shortcomings in monitoring and diagnostic spatial field of view overlap adjustment capabilities: they either lack flexibility or rely on high-cost components. There is an urgent need for a new electronic structure to ensure low-cost and highly flexible channel frequency adjustment of the system, thereby dynamically controlling the overlap range of the diagnostic spatial field of view. Summary of the Invention

[0007] This invention addresses the shortcomings of existing technologies in adjusting the spatial overlap of diagnostic fields, which either lack flexibility or rely on high-cost components. It provides a three-stage frequency conversion electronic cyclotron radiation diagnostic system with adjustable spatial overlap, enabling dynamic control of the degree of spatial overlap and improving the adaptability and practicality of the diagnostic system.

[0008] The present invention is achieved through the following technical solution.

[0009] This invention provides a three-stage frequency conversion electron cyclotron radiation diagnostic system with adjustable diagnostic spatial overlap, the three-stage frequency conversion electron cyclotron radiation diagnostic system with adjustable diagnostic spatial overlap includes:

[0010] Antenna, used to receive electron cyclotron radiation signals from plasma;

[0011] A first-stage mixer, connected to the antenna, is used to mix the electron cyclotron radiation signal with the first-stage local oscillator signal to generate a first intermediate frequency signal.

[0012] A first-stage power divider, connected to the first-stage mixer, is used to distribute the first intermediate frequency signal to multiple first parallel independent channels;

[0013] Multiple secondary mixers are connected one-to-one with multiple first parallel independent channels output by the primary power divider. They are used to mix the first intermediate frequency (IF) signals in the multiple first parallel independent channels with the second-stage local oscillator signals corresponding to the multiple secondary mixers to generate a second IF signal. The frequency of each second-stage local oscillator signal in the multiple secondary mixers is independently adjustable to change the diagnostic spatial position difference between any two first parallel independent channels.

[0014] Multiple secondary power dividers are connected one-to-one with the multiple secondary mixers, and are used to distribute the second intermediate frequency signal output by each of the multiple secondary mixers to multiple second parallel independent channels.

[0015] Multiple three-stage mixers are connected one-to-one with multiple second parallel independent channels output by multiple two-stage power dividers, and are used to mix the second intermediate frequency signals in the multiple second parallel independent channels with the third-stage local oscillator signals corresponding to the multiple three-stage mixers to generate a third intermediate frequency signal.

[0016] Multiple detectors are connected one-to-one with the multiple three-stage mixers to convert the third intermediate frequency signal output by the multiple three-stage mixers into a DC voltage signal, wherein the DC voltage signal is used to represent the original electron cyclotron radiation power.

[0017] In some embodiments, the three-stage frequency conversion electron cyclotron radiation diagnostic system with adjustable diagnostic spatial overlap further includes: a first-stage local oscillator source connected to the first-stage mixer for outputting the first-stage local oscillator source signal.

[0018] In some embodiments, the three-stage frequency conversion electronic cyclotron radiation diagnostic system with adjustable diagnostic spatial overlap further includes: a first-stage amplifier, located between the first-stage mixer and the first-stage power divider and connected to the first-stage mixer and the first-stage power divider respectively, for amplifying the first intermediate frequency signal and inputting it to the first-stage power divider.

[0019] In some embodiments, the three-stage frequency conversion electron cyclotron radiation diagnostic system with adjustable diagnostic spatial overlap further includes: multiple secondary local oscillators, each connected to one of the multiple secondary mixers, for outputting the second-stage local oscillator signal.

[0020] In some embodiments, the three-stage frequency conversion electronic cyclotron radiation diagnostic system with adjustable diagnostic spatial overlap further includes: a plurality of secondary amplifiers, respectively located between the plurality of secondary mixers and the plurality of secondary power dividers and respectively connected to the plurality of secondary mixers and the plurality of secondary power dividers, for amplifying the second intermediate frequency signals in the plurality of second parallel independent channels and inputting them to the plurality of secondary power dividers respectively.

[0021] In some embodiments, the three-stage frequency conversion electronic cyclotron radiation diagnostic system with adjustable diagnostic spatial overlap further includes: a plurality of first-stage filters, which are respectively connected to the plurality of second parallel independent channels and the plurality of third-stage mixers, for bandpass filtering of the second intermediate frequency signal.

[0022] In some embodiments, the three-stage frequency conversion electron cyclotron radiation diagnostic system with adjustable diagnostic spatial overlap further includes: a plurality of three-stage local oscillators, each connected to one of the plurality of three-stage mixers, for outputting a third-stage local oscillator signal, wherein the third-stage local oscillator signal is a fixed frequency.

[0023] In some embodiments, the three-stage frequency conversion electron cyclotron radiation diagnostic system with adjustable diagnostic spatial overlap further includes: a plurality of adjustable attenuators, respectively located between the plurality of three-stage mixers and the plurality of detectors, and connected one-to-one with the plurality of three-stage mixers and the plurality of detectors, for adjusting the amplitude of each third intermediate frequency signal and outputting it to the plurality of detectors respectively.

[0024] In some embodiments, the three-stage frequency conversion electronic cyclotron radiation diagnostic system with adjustable spatial overlap further includes: a plurality of secondary filters, respectively located between the plurality of adjustable attenuators and the plurality of detectors, and connected one-to-one with the plurality of adjustable attenuators and the plurality of detectors, for filtering the signals output by the plurality of adjustable attenuators and outputting them to the plurality of detectors, wherein the plurality of secondary filters each have a fixed bandwidth.

[0025] In some embodiments, the three-stage frequency conversion electron cyclotron radiation diagnostic system with adjustable diagnostic spatial overlap further includes: multiple low-pass filters and multiple three-stage amplifiers, wherein the multiple low-pass filters are connected one-to-one with the multiple three-stage amplifiers, and the multiple low-pass filters are connected one-to-one with the multiple detectors, for filtering the DC voltage signals output by the multiple detectors, and the multiple three-stage amplifiers are used to amplify the signals output by the multiple low-pass filters respectively.

[0026] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0027] (1. By adjusting the frequency of the second-stage local oscillator, the center frequency of the detection channel can be continuously changed without replacing the hardware filter, thereby dynamically adjusting the overlap range of the diagnostic spatial field of view between adjacent channels, which significantly improves the adaptability of the diagnostic system.

[0028] (2. The third stage uses a fixed frequency local oscillator and a fixed bandwidth filter, avoiding the use of YIG tunable filters and greatly reducing system costs;

[0029] (3. The system has high stability and the fixed filter has small temperature drift, making it suitable for long-term experimental operation.) Attached Figure Description

[0030] To more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of a three-stage frequency conversion electron cyclotron radiation diagnostic system with adjustable spatial overlap according to an embodiment of the present invention.

[0032] Figure 2 This is a schematic diagram of the measurement location when the intermediate frequency interval is 0.1 GHz according to an embodiment of the present invention.

[0033] Figure 3 This is a schematic diagram of the measurement location when the intermediate frequency interval is 0.15 GHz according to an embodiment of the present invention.

[0034] Figure label:

[0035] Antenna 1; First-stage mixer 2; First-stage local oscillator 3; First-stage amplifier 4; First-stage power divider 5; Second-stage mixer 6; Second-stage local oscillator (7, 8); Second-stage amplifier 9; Multiple second-stage power dividers 10; First-stage filter 11; Multiple third-stage mixers 12; Third-stage local oscillator (13, 14); Adjustable attenuator 15; Second-stage filter 16; Detector 17; Low-pass filter 18; Third-stage amplifier 19; Acquisition circuit 20. Detailed Implementation

[0036] In the following, the terms “comprising” or “may include” as used in various embodiments of the invention indicate the presence of an inventive function, operation, or element, and do not limit the addition of one or more functions, operations, or elements. Furthermore, as used in various embodiments of the invention, the terms “comprising,” “having,” and their cognates are intended only to indicate a specific feature, number, step, operation, element, component, or combination of the foregoing, and should not be construed as primarily excluding the presence of one or more other features, numbers, steps, operations, elements, components, or combinations of the foregoing, or adding one or more combinations of the foregoing.

[0037] In various embodiments of the invention, the expression "or" or "at least one of A and / or B" includes any combination or all combinations of the words listed simultaneously. For example, the expression "A or B" or "at least one of A and / or B" may include A, may include B, or may include both A and B.

[0038] The expressions used in the various embodiments of the present invention (such as "first," "second," etc.) may modify various constituent elements in the various embodiments, but do not limit the corresponding constituent elements. For example, the above expressions do not limit the order and / or importance of the elements. The above expressions are only used for the purpose of distinguishing one element from other elements. For example, a first user device and a second user device refer to different user devices, although both are user devices. For example, a first element may be referred to as a second element without departing from the scope of the various embodiments of the present invention, and similarly, a second element may also be referred to as a first element.

[0039] It should be noted that if a description is made of "connecting" one component to another, then the first component can be directly connected to the second component, and a third component can be "connected" between the first and second components. Conversely, when a component is "directly connected" to another component, it can be understood that there is no third component between the first and second components.

[0040] The terminology used in the various embodiments of the invention is for the purpose of describing particular embodiments only and is not intended to limit the various embodiments of the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which the various embodiments of the invention pertain. The terms (such as those defined in a generally used dictionary) are to be interpreted as having the same meaning as in the context of the relevant technical field and are not to be interpreted as having an idealized or overly formal meaning, unless clearly defined in the various embodiments of the invention.

[0041] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0042] To address the issues of unadjustable or excessively costly adjustment range of the diagnostic spatial field of view overlap in existing CECE systems, this invention provides a novel three-stage frequency conversion electronics structure that enables flexible adjustment of the center frequency of adjacent channels without using YIG filters. This allows for dynamic control of the degree of overlap in the diagnostic spatial field of view, thereby improving the adaptability and practicality of the diagnostic system.

[0043] This invention provides a three-stage frequency conversion electron cyclotron radiation diagnostic system with adjustable diagnostic spatial overlap. Figure 1 This is a schematic diagram of a three-stage frequency conversion electron cyclotron radiation diagnostic system with adjustable spatial overlap according to an embodiment of the present invention. (Reference) Figure 1 The adjustable diagnostic spatial overlap three-stage frequency conversion electronic cyclotron radiation diagnostic system includes at least: antenna 1, primary mixer 2, primary power divider 5, multiple secondary mixers 6, multiple secondary power dividers 10, multiple tertiary mixers 12, and multiple detectors 17.

[0044] Antenna 1 is used to receive electron cyclotron radiation signals from the plasma. Exemplarily, antenna 1 is used to receive electron cyclotron radiation signals from the plasma and transmit them to subsequent electronic systems.

[0045] A first-stage mixer 2, connected to antenna 1, is used to mix the electron cyclotron radiation signal with the first-stage local oscillator signal to generate a first intermediate frequency signal. Exemplarily, the first-stage mixer 2, as a first-stage mixing unit, mixes the radio frequency signal received by the antenna with the first-stage local oscillator signal.

[0046] A first-stage power divider 5, connected to a first-stage mixer 2, is used to distribute the first intermediate frequency signal to multiple first parallel independent channels. For example, the first-stage power divider 5 distributes the amplified first intermediate frequency signal to multiple parallel channels for subsequent multiplexing.

[0047] Multiple secondary mixers 6 are connected one-to-one with multiple parallel independent channels output from the primary power divider 5. They are used to mix the first intermediate frequency (IF) signals from the multiple first parallel independent channels with the second-stage local oscillator signals corresponding to each of the multiple secondary mixers 6 to generate a second IF signal. The frequency of each second-stage local oscillator signal in the multiple secondary mixers 6 is independently adjustable to change the diagnostic spatial position difference between the two parallel independent channels. For example, the secondary mixer 6, as a second-stage mixing unit, mixes the first IF signal with the second-stage local oscillator signal again to generate the second IF signal.

[0048] Multiple secondary power dividers 10 are connected one-to-one with multiple secondary mixers 6, and are used to distribute the second intermediate frequency signal output by each secondary mixer 6 to multiple second parallel independent channels. For example, the secondary power dividers 10 further distribute the second intermediate frequency signal to multiple third-stage processing channels, supporting multi-channel parallel detection.

[0049] Multiple three-stage mixers 12 are connected one-to-one with multiple second parallel independent channels output by multiple two-stage power dividers 10, respectively, to mix the second intermediate frequency (IF) signals in the multiple second parallel independent channels with the third-stage local oscillator signals corresponding to the multiple three-stage mixers 12 to generate a third IF signal. For example, the three-stage mixer 12 serves as a third-stage mixing unit, mixing the second IF signal with the third-stage local oscillator signal to generate the final IF signal.

[0050] Multiple detectors 17 are connected one-to-one with multiple three-stage mixers 12 to convert the third intermediate frequency signal output by the multiple three-stage mixers 12 into a DC voltage signal, wherein the DC voltage signal is used to represent the original electron cyclotron radiation power. Exemplarily, the detectors 17 convert the final intermediate frequency signal into a DC voltage signal and output a DC voltage signal representing the original radiation power.

[0051] In some embodiments, the three-stage frequency conversion electron cyclotron radiation diagnostic system for adjusting the spatial overlap of the diagnostic system further includes: a first-stage local oscillator 3, connected to a first-stage mixer 2, for outputting a first-stage local oscillator signal. Exemplarily, the first-stage local oscillator 3 provides the first-stage local oscillator signal for mixing with the signal output from the first-stage mixer 2 to generate a first intermediate frequency signal.

[0052] In some embodiments, the three-stage frequency conversion electronic cyclotron radiation diagnostic system for adjusting the spatial overlap of diagnostics further includes: a first-stage amplifier 4, located between the first-stage mixer 2 and the first-stage power divider 5 and connected to both the first-stage mixer 2 and the first-stage power divider 5, for amplifying the first intermediate frequency signal and inputting it to the first-stage power divider 5. Exemplarily, the first-stage amplifier 4 amplifies the first intermediate frequency signal to compensate for the mixing loss in the preceding stage and improve the signal-to-noise ratio.

[0053] In some embodiments, the three-stage frequency conversion electron cyclotron radiation diagnostic system for adjusting the spatial overlap of the diagnostic system further includes: multiple secondary local oscillators (7, 8), each connected to a corresponding secondary mixer 6, for outputting secondary local oscillator signals. Exemplarily, the secondary local oscillators (7, 8) provide adjustable frequency secondary local oscillator signals for different channels; by adjusting their output frequency, the secondary intermediate frequency center frequency of the corresponding channel can be changed. This invention is illustrated using two secondary local oscillators corresponding to two channels as an example, but the invention is not limited thereto.

[0054] In some embodiments, the three-stage frequency conversion electronic cyclotron radiation diagnostic system for adjusting the spatial overlap further includes: a plurality of secondary amplifiers 9, respectively located between a plurality of secondary mixers 6 and a plurality of secondary power dividers 10 and respectively connected to the plurality of secondary mixers 6 and the plurality of secondary power dividers 10, for amplifying the second intermediate frequency signals in the plurality of second parallel independent channels and then inputting them to the plurality of secondary power dividers 10 respectively. Exemplarily, the secondary amplifiers 9 amplify the second intermediate frequency signals to ensure that the signal strength meets the requirements of subsequent processing.

[0055] In some embodiments, the three-stage frequency conversion electronic cyclotron radiation diagnostic system for adjusting the spatial overlap further includes: a plurality of first-stage filters 11, respectively located between a plurality of second parallel independent channels and a plurality of third-stage mixers 12 and respectively connected in a one-to-one correspondence with the plurality of second parallel independent channels and the plurality of third-stage mixers 12, for bandpass filtering of the second intermediate frequency signal. Exemplarily, the first-stage filters 11 perform bandpass filtering on the second intermediate frequency signal to suppress out-of-band noise and retain the target frequency band.

[0056] In some embodiments, the three-stage frequency conversion electron cyclotron radiation diagnostic system for adjusting the spatial overlap further includes: a plurality of three-stage local oscillators (13, 14), each connected to a plurality of three-stage mixers 12 in a one-to-one correspondence, for outputting a third-stage local oscillator signal, wherein the third-stage local oscillator signal is of a fixed frequency. Exemplarily, the three-stage local oscillators (13, 14) provide a fixed-frequency third-stage local oscillator signal for down-converting the signal to the final intermediate frequency range. This invention is illustrated using two three-stage local oscillators corresponding to two channels as an example, but the invention is not limited thereto.

[0057] In some embodiments, the three-stage frequency conversion electronic cyclotron radiation diagnostic system for adjusting the spatial overlap of the diagnostic system further includes: a plurality of adjustable attenuators 15, respectively located between a plurality of three-stage mixers 12 and a plurality of detectors 17, and connected one-to-one with the plurality of three-stage mixers 12 and a plurality of detectors 17, for adjusting the amplitude of each third intermediate frequency signal and outputting it to the plurality of detectors 17 respectively. Exemplarily, the adjustable attenuators 15 are used to adjust the signal amplitude, prevent overload of subsequent circuits, and adapt to different signal strength scenarios.

[0058] In some embodiments, the three-stage frequency conversion electronic cyclotron radiation diagnostic system for adjusting the spatial overlap of the diagnostic system further includes: a plurality of secondary filters 16, respectively located between a plurality of adjustable attenuators 15 and a plurality of detectors 17, and connected one-to-one with the plurality of adjustable attenuators 15 and the plurality of detectors 17, for filtering the signals output by the plurality of adjustable attenuators 15 and outputting them to the plurality of detectors 17, wherein each of the plurality of secondary filters 16 has a fixed bandwidth. Exemplarily, the secondary filters 16 filter the final intermediate frequency signal to further suppress spurious components.

[0059] In some embodiments, the three-stage frequency conversion electronic cyclotron radiation diagnostic system for adjusting the spatial overlap of the diagnostic system further includes: a plurality of low-pass filters 18 and a plurality of three-stage amplifiers 19, wherein the plurality of low-pass filters 18 are connected one-to-one with the plurality of three-stage amplifiers 19, and the plurality of low-pass filters 18 are connected one-to-one with the plurality of detectors 17, for filtering the DC voltage signals output by the plurality of detectors 17, wherein the plurality of three-stage amplifiers 19 are used to amplify the signals output by the plurality of low-pass filters 18. Exemplarily, the low-pass filters 18 are used to filter out the high-frequency components remaining after detection to obtain a smooth analog output; the three-stage amplifiers 19 are used to amplify the detected output signal to improve the dynamic range and signal-to-noise ratio.

[0060] In some embodiments, the three-stage frequency conversion electron cyclotron radiation diagnostic system for adjusting the spatial overlap of the diagnostic system further includes: an acquisition circuit (ACQ) 20, which is connected to multiple three-stage amplifiers 19 to access a high-speed data acquisition system and synchronously record the output signals of all channels for subsequent digital processing and cross-correlation analysis.

[0061] Based on the above description, this invention provides a three-stage frequency conversion electronic cyclotron radiation diagnostic system with adjustable spatial overlap. The system may include an antenna 1, a first-stage mixer 2, a first-stage local oscillator 3, a first-stage amplifier 4, a first-stage power divider 5, multiple second-stage mixers 6, multiple second-stage local oscillators (7, 8), multiple second-stage amplifiers 9, multiple second-stage power dividers 10, multiple first-stage filters 11, multiple third-stage mixers 12, multiple third-stage local oscillators (13, 14), multiple adjustable attenuators 15, multiple second-stage filters 16, multiple detectors 17, multiple low-pass filters 18, multiple third-stage amplifiers 19, and a data acquisition circuit 20. This structure constitutes a three-stage frequency conversion CECE electronic structure. This three-stage frequency conversion CECE electronic structure achieves frequency adjustment flexibility with a small increase in hardware cost, demonstrating good engineering practicality and promotional value.

[0062] The following combination Figure 1 The working process of the three-stage frequency conversion electron cyclotron radiation diagnostic system with adjustable diagnostic spatial overlap is described, and its working process mainly involves digital processing and cross-correlation analysis.

[0063] When this three-stage frequency conversion electron cyclotron radiation diagnostic system with adjustable spatial overlap is in operation, antenna 1 first receives electron cyclotron radiation signals from the plasma. Then, the radio frequency signal (electron cyclotron radiation from the plasma) received by antenna 1 is mixed with the signal from the first-stage local oscillator to generate a first intermediate frequency (IF) signal. This first IF signal is amplified by a first-stage amplifier 4 (to increase the gain of the first IF signal, compensate for the mixing loss in the previous stage, and improve the signal-to-noise ratio), and then distributed by a first-stage power divider 5 to multiple parallel independent channels (distributing the amplified first IF signal to multiple parallel channels). In each parallel independent channel, a second-stage mixer 6 mixes the first IF signal with the adjustable second-stage local oscillator signal to generate a second IF signal. Since the frequency of the second-stage local oscillator is adjustable, the center frequency of the second IF signal for each channel can be set independently. The second-stage local oscillator signal can be provided to different channels by the second-stage local oscillator (7, 8) respectively (that is, the second-stage local oscillator 7 and 8 provide adjustable frequency second-stage local oscillator signals to different channels respectively, and by adjusting their output frequency, the second intermediate frequency center frequency of the corresponding channel can be changed).

[0064] Subsequently, the second intermediate frequency signal is amplified by the second-stage amplifier 9 to ensure that the signal strength meets the requirements of subsequent processing. The amplified second intermediate frequency signal is then filtered by the second-stage filter 11 (to perform bandpass filtering on the second intermediate frequency signal, suppress out-of-band noise, and retain the target frequency band) before being input into the third-stage frequency conversion stage.

[0065] In the third-stage frequency conversion stage, the amplified second intermediate frequency (IF) signal is mixed with the third-stage local oscillator signal with a fixed frequency by a three-stage mixer 12 to generate the final IF signal. The third-stage local oscillator signal is generated by three-stage local oscillators (13, 14) and input to the corresponding channels. This final IF signal is then sent to the high-speed acquisition system ACQ after detection, low-pass filtering, and video amplification. Specifically, before the final IF signal enters the high-speed acquisition system ACQ, the adjustable attenuator 15 processes the final IF signal to adjust the signal amplitude, prevent overload of subsequent circuits, and adapt to different signal strength scenarios. A second-stage filter 16 filters the signal output from the adjustable attenuator 15 and outputs it to the detector 17. Each of the second-stage filters 16 has a fixed bandwidth. Additionally, a low-pass filter 18 filters the DC voltage signal output from the detector 17, and a three-stage amplifier 13 amplifies the signal output from the low-pass filter 18.

[0066] The acquired signals contain information about electron temperature fluctuations, which can be used to calculate the cross-correlation function between adjacent channels. By adjusting the frequency difference of the second-stage local oscillator, the diagnostic spatial position difference between the two channels can be changed, thereby achieving dynamic adjustment of the overlap range of their diagnostic spatial fields of view.

[0067] In this invention, a three-stage frequency conversion CECE electronic system is constructed by introducing an adjustable second-stage local oscillator, which realizes flexible control of the center frequency of the detection channel.

[0068] Compared with the prior art, the present invention has the following technical effects:

[0069] (1. By adjusting the frequency of the second-stage local oscillator, the center frequency of the detection channel can be continuously changed without replacing the hardware filter, thereby dynamically adjusting the overlap range of the diagnostic spatial field of view between adjacent channels, which significantly improves the adaptability of the diagnostic system.

[0070] (2. The third stage uses a fixed frequency local oscillator and a fixed bandwidth filter, avoiding the use of YIG tunable filters and greatly reducing system costs;

[0071] (3. The system has high stability and the fixed filter has small temperature drift, making it suitable for long-term experimental operation.)

[0072] The present invention will now be described in further detail with reference to the accompanying drawings and specific application embodiments.

[0073] refer to Figure 1 Construct a CECE system, set the parameters of each structural component in the system, and implement the following process:

[0074] The frequency range of ECE (electron cyclotron radiation) signals received by the antenna is 76–88 GHz;

[0075] The frequency of the first-stage local oscillator (LO1) is set to 60 GHz, and after mixing, the first intermediate frequency IF1 is generated with a frequency range of 16–28 GHz.

[0076] IF1 is split into two paths by the power divider, and each path enters a separate channel.

[0077] In path A, the frequency of the second-stage local oscillator (LO2_A) is set to 15 GHz, and after mixing, IF2_A (1–13 GHz) is generated.

[0078] In channel B, the LO2_B frequency is set to 15.1 GHz, generating IF2_B (0.9–12.9 GHz).

[0079] After being filtered, the IF2 signal enters the third stage and is mixed with LO3 to generate the final intermediate frequency IF3 (0.5–0.6 GHz).

[0080] After being detected, low-pass filtered, and amplified, the IF3 signal is sent to the high-speed acquisition system (sampling rate 5 MS / s).

[0081] The collected data is digitally processed to extract fluctuation signals.

[0082] At this point, the center frequency difference between the two channels is 0.1 GHz, and the overlapping portion of the field of view is relatively large when the circumferential magnetic field is 1.6 T. Figure 2 As shown.

[0083] Adjusting the LO2_B frequency to 15.15 GHz increases the center frequency difference between the two channels to 0.15 GHz. This results in an increased radial distance and a decreased overlap area in the diagnostic space field of view. Figure 3 As shown.

[0084] By adjusting the LO2 frequency, the system can adaptively adjust the detection mode at different discharge stages, verifying the advantages of the present invention in dynamic adjustment capability.

[0085] This invention proposes a three-stage frequency conversion electron cyclotron radiation diagnostic system (a novel three-stage frequency conversion structure) with adjustable diagnostic spatial overlap. By introducing an adjustable local oscillator in the second stage, it achieves flexible adjustment of the center frequency of the detection channel, thereby dynamically controlling the diagnostic spatial field-of-view overlap range of adjacent channels. This scheme eliminates the need for high-cost adjustable filters such as YIG filters, and has advantages such as reasonable structure, low cost, good stability, and easy expansion. It is particularly suitable for fusion plasma diagnostic scenarios that require adaptation to multi-scale turbulence measurements. This structure is not only applicable to CECE but can also be extended to other microwave diagnostic systems that require multi-channel frequency fine-tuning.

[0086] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A three-stage frequency conversion electron cyclotron radiation diagnostic system with adjustable diagnostic spatial overlap, characterized in that, The system includes: Antenna, used to receive electron cyclotron radiation signals from plasma; A first-stage mixer, connected to the antenna, is used to mix the electron cyclotron radiation signal with the first-stage local oscillator signal to generate a first intermediate frequency signal. A first-stage power divider, connected to the first-stage mixer, is used to distribute the first intermediate frequency signal to multiple first parallel independent channels; Multiple secondary mixers are connected one-to-one with multiple first parallel independent channels output by the primary power divider. They are used to mix the first intermediate frequency (IF) signals in the multiple first parallel independent channels with the second-stage local oscillator signals corresponding to the multiple secondary mixers to generate a second IF signal. The frequency of each second-stage local oscillator signal in the multiple secondary mixers is independently adjustable to change the diagnostic spatial position difference between any two first parallel independent channels. Multiple secondary power dividers are connected one-to-one with the multiple secondary mixers, and are used to distribute the second intermediate frequency signal output by each of the multiple secondary mixers to multiple second parallel independent channels. Multiple three-stage mixers are connected one-to-one with multiple second parallel independent channels output by multiple two-stage power dividers, and are used to mix the second intermediate frequency signals in the multiple second parallel independent channels with the third-stage local oscillator signals corresponding to the multiple three-stage mixers to generate a third intermediate frequency signal. Multiple detectors are connected one-to-one with the multiple three-stage mixers to convert the third intermediate frequency signal output by the multiple three-stage mixers into a DC voltage signal, wherein the DC voltage signal is used to represent the original electron cyclotron radiation power.

2. The system according to claim 1, characterized in that, The system further includes: a first-stage local oscillator, connected to the first-stage mixer, for outputting the first-stage local oscillator signal.

3. The system according to claim 2, characterized in that, The system further includes: a first-stage amplifier, located between the first-stage mixer and the first-stage power divider and connected to the first-stage mixer and the first-stage power divider respectively, for amplifying the first intermediate frequency signal and inputting it to the first-stage power divider.

4. The system according to claim 3, characterized in that, The system further includes: multiple secondary local oscillators, each connected to one of the multiple secondary mixers, for outputting the second-stage local oscillator signal.

5. The system according to claim 4, characterized in that, The system further includes: multiple secondary amplifiers, located between the multiple secondary mixers and multiple secondary power dividers and connected one-to-one with the multiple secondary mixers and multiple secondary power dividers, for amplifying the second intermediate frequency signals in the multiple second parallel independent channels and inputting them to the multiple secondary power dividers respectively.

6. The system according to claim 5, characterized in that, The system further includes: multiple first-stage filters, which are respectively connected to the multiple second parallel independent channels and the multiple third-stage mixers, for bandpass filtering of the second intermediate frequency signal.

7. The system according to claim 6, characterized in that, The system further includes: multiple three-stage local oscillators, each connected to one of the multiple three-stage mixers, for outputting a third-stage local oscillator signal, wherein the third-stage local oscillator signal has a fixed frequency.

8. The system according to claim 7, characterized in that, The system further includes: multiple adjustable attenuators, located between the multiple three-stage mixers and the multiple detectors respectively, and connected one-to-one with the multiple three-stage mixers and the multiple detectors, for adjusting the amplitude of the third intermediate frequency signal and outputting it to the multiple detectors.

9. The system according to claim 8, characterized in that, The system further includes: multiple secondary filters, located between the multiple adjustable attenuators and the multiple detectors respectively, and connected one-to-one with the multiple adjustable attenuators and the multiple detectors, for filtering the signals output by the multiple adjustable attenuators and outputting them to the multiple detectors, wherein each of the multiple secondary filters has a fixed bandwidth.

10. The system according to claim 9, characterized in that, The system further includes: multiple low-pass filters and multiple three-stage amplifiers, wherein the multiple low-pass filters are connected one-to-one with the multiple three-stage amplifiers, and the multiple low-pass filters are connected one-to-one with the multiple detectors, for filtering the DC voltage signals output by the multiple detectors, and the multiple three-stage amplifiers are used to amplify the signals output by the multiple low-pass filters respectively.

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