Mirror image tuning method based on electron paramagnetic resonance spectrometer and storage medium

Abstract

The invention discloses a mirror image tuning method based on an electron paramagnetic resonance spectrometer and a storage medium, and the method comprises the steps: obtaining a sample path signal generated by a microwave link and a noise reference signal generated by a noise mirror image link, and generating a main path tuning curve according to the sample path signal, generating a mirror image main path tuning curve according to the noise reference signal; according to the main path tuning curve, controlling a microwave source to generate a microwave signal of which the frequency is the same as the sample resonant frequency of a to-be-detected sample in a sample resonant cavity on the main path; and adjusting the frequency and the reference path of the sample resonant cavity according to the main path tuning curve, adjusting the frequency of the mirror image resonant cavity on the mirror image main path according to the frequency of the sample resonant cavity, and adjusting the mirror image reference path according to the mirror image main path tuning curve. According to the method, the correlation between the sample path signal and the noise reference signal is improved, the effect of carrying out noise suppression on the sample path signal according to the noise reference signal is further improved, and the signal-to-noise ratio of the EPR is effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of electron paramagnetic resonance spectroscopy, and in particular, to a mirror tuning method and a storage medium based on an electron paramagnetic resonance spectrometer. Background Art

[0002] The signal-to-noise ratio is a key index of an electron paramagnetic resonance spectrometer (EPR), which is defined as the ratio of the signal amplitude of a standard sample at low power to the noise amplitude at high power after power conversion. To require the signal-to-noise ratio to be as high as possible, the noise needs to be as low as possible. A conventional solution to meet the above requirements is to use a wave source with low phase noise. However, using a wave source with low phase noise cannot meet the requirements for the signal-to-noise ratio of the electron paramagnetic resonance spectrometer during operation. Summary of the Invention

[0003] The present invention aims to solve at least one of the technical problems in the related art to some extent. For this purpose, an object of the present invention is to provide a mirror tuning method based on an electron paramagnetic resonance spectrometer, which improves the correlation between the sample path signal and the noise reference signal, and further improves the effect of noise suppression on the sample path signal according to the noise reference signal.

[0004] A second object of the present invention is to provide a computer-readable storage medium.

[0005] A third object of the present invention is to provide a controller.

[0006] To achieve the above object, an embodiment of the first aspect of the present invention provides a mirror tuning method based on an electron paramagnetic resonance spectrometer. The electron paramagnetic resonance spectrometer includes a microwave wave source, a microwave link, and a noise mirror link that is a mirror image of the microwave link. The microwave link includes a main path and a reference path, and the noise mirror link includes a mirror main path and a mirror reference path. The microwave wave source is respectively connected to the main path, the reference path, the mirror main path, and the mirror reference path. The method includes: acquiring a sample path signal generated by the microwave link and a noise reference signal generated by the noise mirror link, generating a main path tuning curve according to the sample path signal, and generating a mirror main path tuning curve according to the noise reference signal; controlling the microwave wave source to generate a microwave signal with a frequency the same as the sample resonance frequency of the sample to be measured in the sample resonator on the main path according to the main path tuning curve; adjusting the frequency of the sample resonator and the reference path according to the main path tuning curve, adjusting the frequency of the mirror resonator on the mirror main path according to the frequency of the sample resonator, and adjusting the mirror reference path according to the mirror main path tuning curve.

[0007] According to the mirror tuning method of an embodiment of the present invention, the sample path signal generated by the microwave link and the noise reference signal generated by the noise mirror link in an electron paramagnetic resonance spectrometer are tuned to improve the correlation between the sample path signal and the noise reference signal, so as to further improve the effect of noise suppression on the sample path signal according to the noise reference signal, and effectively improve the signal-to-noise ratio of EPR.

[0008] In addition, the mirror tuning method based on an electron paramagnetic resonance spectrometer proposed according to the above embodiment of the present invention may further have the following additional technical features:

[0009] According to an embodiment of the present invention, the electron paramagnetic resonance spectrometer further includes a power amplifier, a first power splitter, a main path attenuator, a second power splitter, and a third power splitter. The output end of the microwave source is connected to the input end of the power amplifier, the output end of the power amplifier is connected to the input end of the first power splitter, the first output end of the first power splitter is connected to the input end of the second power splitter, the first output end of the second power splitter is connected to the input end of the reference path, the second output end of the second power splitter is connected to the input end of the mirror reference path, the second output end of the first power splitter is connected to the input end of the main path attenuator, the output end of the main path attenuator is connected to the input end of the third power splitter, the first output end of the third power splitter is connected to the input end of the main path, and the second output end of the third power splitter is connected to the input end of the mirror main path; wherein, adjusting the frequency of the sample resonator according to the main path tuning curve includes: adjusting the attenuation value of the main path attenuator to a first preset attenuation value, and adjusting the resonance rod of the sample resonator so that the lowest point of the main path tuning curve reaches a first target value.

[0010] According to an embodiment of the present invention, the main path includes a main modulation field device for providing the main modulation field to the sample to be measured. The main modulation field device includes a sample resonator and a first circulator. The reference path includes a first phase shifter and a first attenuator. The input end of the first phase shifter is the input end of the reference path, and the output end of the first phase shifter is connected to the input end of the first attenuator. The main path further includes a first low-noise amplifier, a first directional coupler, a first detector, and a first signal conditioning circuit board. The first input end of the first circulator is the input end of the main path, the output end of the sample resonator is connected to the second input end of the first circulator, the output end of the first circulator is connected to the input end of the first low-noise amplifier, the output end of the first low-noise amplifier is connected to the first input end of the first directional coupler, the output end of the first attenuator is connected to the second input end of the first directional coupler, the output end of the first directional coupler is connected to the input end of the first detector, the output end of the first detector is connected to the input end of the first signal conditioning circuit board, and the output end of the first signal conditioning circuit board is connected to the input end of the lock-in amplifier. Before controlling the microwave source to generate a microwave signal with a frequency equal to the sample resonance frequency, the attenuation value of the first attenuator is adjusted to the maximum.

[0011] According to an embodiment of the present invention, the image main path includes an image modulation field device for providing the image modulation field. The image modulation field device includes an image resonator and a second circulator. The image reference path includes a second phase shifter and a second attenuator. The input end of the second phase shifter is the input end of the image reference path, and the output end of the second phase shifter is connected to the input end of the second attenuator. The image main path includes a second low-noise amplifier, a second directional coupler, a second detector, and a second signal conditioning circuit board. The first input end of the second circulator is used as the input end of the image main path, the output end of the image resonator is connected to the second input end of the second circulator, the output end of the second circulator is connected to the input end of the second low-noise amplifier, the output end of the second low-noise amplifier is connected to the first input end of the second directional coupler, the output end of the second attenuator is connected to the second input end of the second directional coupler, the output end of the second directional coupler is connected to the input end of the second detector, the output end of the second detector is connected to the input end of the second signal conditioning circuit board, and the output end of the second signal conditioning circuit board is connected to the input end of the lock-in amplifier. Before adjusting the frequency of the image resonator on the image main path according to the frequency of the sample resonator, the attenuation value of the second attenuator is adjusted to the maximum.

[0012] According to an embodiment of the present invention, adjusting the reference path according to the main path tuning curve includes: adjusting the attenuation value of the main path attenuator to the maximum, and adjusting the attenuation value of the first attenuator so that the lowest point of the main path tuning curve reaches a second target value, where the second target value is greater than the first target value; adjusting the attenuation value of the main path attenuator to the first preset attenuation value, and adjusting the first phase shifter so that the resonance frequency of the main path returns to the sample resonance frequency.

[0013] According to an embodiment of the present invention, adjusting the mirror reference path according to the mirror main path tuning curve includes: adjusting the attenuation value of the main path attenuator to the maximum, and adjusting the attenuation value of the second attenuator so that the lowest point of the mirror main path tuning curve reaches the second target value; adjusting the attenuation value of the main path attenuator to the first preset attenuation value, and adjusting the second phase shifter so that the resonance frequency of the mirror main path returns to the sample resonance frequency.

[0014] According to an embodiment of the present invention, after the adjustment of the microwave link and the noise mirror link is completed, the method includes: demodulating the sample path signal and the noise reference signal respectively by a lock-in amplifier to obtain a sample path signal sequence and a noise reference signal sequence; statistically analyzing the sample path signal sequence and the noise reference signal sequence within a preset time period to obtain a first statistic and a second statistic, where the preset time period is a time period taken during the generation of the full noise signal by the electron paramagnetic resonance spectrometer; obtaining a target sample path signal according to the first statistic, the second statistic, the sample path signal sequence, and the noise reference signal sequence.

[0015] According to an embodiment of the present invention, the first statistic includes a sample path mean and a sample path standard deviation, and the second statistic includes a mirror path mean and a mirror path standard deviation. Obtaining the target sample path signal according to the first statistic, the second statistic, the sample path signal sequence, and the noise reference signal sequence includes: subtracting the sample path signal in the sample path signal sequence from the sample path mean to obtain a first difference signal sequence; subtracting the noise reference signal in the noise reference signal sequence from the mirror path mean to obtain a second difference signal sequence, and multiplying the second difference signal in the second difference signal sequence by the ratio of the sample path standard deviation to the mirror path standard deviation to obtain a product value signal sequence; subtracting the first difference signal in the first difference signal sequence from the product value signal in the product value signal sequence to obtain the electron paramagnetic resonance spectrum of the sample to be measured.

[0016] To achieve the above object, an embodiment of the second aspect of the present invention provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the mirror tuning method proposed in the embodiment of the first aspect of the present invention is implemented.

[0017] To achieve the above object, an embodiment of the third aspect of the present invention provides a controller, including a memory and a processor. A computer program is stored on the memory. When the computer program is executed by the processor, the mirror tuning method proposed in the embodiment of the first aspect of the present invention is implemented.

[0018] Additional aspects and advantages of the present invention will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present invention. Description of the Drawings

[0019] Figure 1 is a schematic diagram of an electron paramagnetic resonance spectrometer according to an embodiment of the present invention;

[0020] Figure 2 is a flowchart of a noise suppression method according to an embodiment of the present invention;

[0021] Figure 3 is a flowchart of obtaining a target sample path signal according to an embodiment of the present invention;

[0022] Figure 4 is a flowchart of obtaining a target sample path signal according to a specific embodiment of the present invention;

[0023] Figure 5 is a waveform schematic diagram of a sample path signal, a mirror path signal, and a target sample path signal according to an embodiment of the present invention;

[0024] Figure 6 is an effect diagram of noise suppression based on mirror cancellation according to an embodiment of the present invention;

[0025] Figure 7 is an effect diagram of noise suppression at different powers according to an embodiment of the present invention;

[0026] Figure 8 is a flowchart of a mirror tuning method according to an embodiment of the present invention;

[0027] Figure 9 is a structural block diagram of a controller according to an embodiment of the present invention. Detailed Embodiments

[0028] Embodiments of the present invention will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the accompanying drawings are exemplary and are intended to explain the present invention, and should not be construed as limiting the present invention.

[0029] The following combines the description of the specification Figures 1-9 and specific implementation manners to detail the mirror tuning method and storage medium based on an electron paramagnetic resonance spectrometer according to the embodiments of the present invention.

[0030] The present invention provides an electron paramagnetic resonance spectrometer.

[0031] Figure 1 is a schematic diagram of an electron paramagnetic resonance spectrometer according to an embodiment of the present invention. As Figure 1 shown, the electron paramagnetic resonance spectrometer includes a microwave source, a power amplifier, a first power splitter, a main path attenuator, a second power splitter, a third power splitter, a microwave link, and a noise mirror link that mirrors the microwave link. Among them, the microwave link includes a main path and a reference path, and the noise mirror link includes a mirror main path and a mirror reference path. The output end of the microwave source is connected to the input end of the power amplifier, the output end of the power amplifier is connected to the input end of the first power splitter, the first output end of the first power splitter is connected to the input end of the second power splitter, the first output end of the second power splitter is connected to the input end of the reference path, the second output end of the second power splitter is connected to the input end of the mirror reference path, the second output end of the first power splitter is connected to the input end of the main path attenuator, the output end of the main path attenuator is connected to the input end of the third power splitter, the first output end of the third power splitter is connected to the input end of the main path, and the second output end of the third power splitter is connected to the input end of the mirror main path.

[0032] The microwave link according to the embodiment of the present invention is used to generate a sample path signal. In the related art, the electron paramagnetic resonance spectrum of the sample to be measured is directly determined according to the sample path signal generated by the microwave link.

[0033] To improve the signal-to-noise ratio of the electron paramagnetic resonance spectrometer and effectively reduce the influence of the noise generated by the electron paramagnetic resonance spectrometer on the electron paramagnetic resonance spectrum of the sample to be measured, the embodiment of the present invention adds a noise mirror link that mirrors the microwave link, uses the noise mirror link to generate a noise reference signal, and performs denoising processing on the sample path signal generated by the microwave link based on the noise reference signal generated by the noise mirror link, and determines the electron paramagnetic resonance spectrum of the sample to be measured using the target sample path signal obtained after denoising.

[0034] In a specific embodiment of the present invention, as Figure 1As shown, the main path includes a main modulation field device for providing a main modulation field to the sample under test. The main modulation field device includes a sample resonator cavity and a first circulator. The main path further includes a first low-noise amplifier, a first directional coupler, a first detector, and a first signal conditioning circuit board. The first input terminal of the first circulator is the input terminal of the main path. The output terminal of the sample resonator cavity is connected to the second input terminal of the first circulator. The output terminal of the first circulator is connected to the input terminal of the first low-noise amplifier. The output terminal of the first low-noise amplifier is connected to the first input terminal of the first directional coupler. The output terminal of the first attenuator is connected to the second input terminal of the first directional coupler. The output terminal of the first directional coupler is connected to the input terminal of the first detector. The output terminal of the first detector is connected to the input terminal of the first signal conditioning circuit board. The output terminal of the first signal conditioning circuit board is used to output the sample path signal. The reference path includes a first phase shifter and a first attenuator. The input terminal of the first phase shifter is the input terminal of the reference path. The output terminal of the first phase shifter is connected to the input terminal of the first attenuator.

[0035] See Figure 1 , a first phase shifter and a first attenuator are provided on the reference path. A main modulation field device, a first low-noise amplifier, a first directional coupler, a first detector, and a first signal conditioning circuit board are provided on the main path. Among them, the first signal conditioning circuit board has three output terminals. The first output terminal of the first signal conditioning circuit board is connected to an oscilloscope to display the main path tuning curve through the oscilloscope. The second output terminal of the first signal conditioning circuit board is connected to the input terminal of a lock-in amplifier to transmit the sample path signal to the lock-in amplifier. The third output terminal of the first signal conditioning circuit board is connected to a host computer to control a microwave source to generate a microwave signal having the same frequency as the sample resonance frequency of the sample under test through the host computer.

[0036] In an embodiment of the present invention, the main modulation field device includes a sample resonator cavity, and a modulation coil is disposed around the sample resonator cavity. The sample resonator cavity is used to place the sample under test, and the modulation coil is used to provide a modulation field. The microwave link combines the microwave signal generated by the microwave source to modulate the sample under test in the sample resonator cavity to generate a sample path signal.

[0037] It should be noted that the magnetic moments of the unpaired electrons of the sample under test are in two groups at different energy levels under the action of an external magnetic field (modulation field). One group is parallel to the external magnetic field (low energy level) and accounts for the majority. The other group is anti-parallel to the external magnetic field (high energy level) and accounts for the minority. However, the electrons in the low energy level can absorb electromagnetic waves of a specific frequency and transition to the high energy level under certain conditions.

[0038] In a specific embodiment of the present invention, as Figure 1As shown, the mirror main path includes a mirror modulation field device for providing a mirror modulation field. The mirror modulation field device includes a mirror resonator and a second circulator. The mirror main path includes a second low-noise amplifier, a second directional coupler, a second detector, and a second signal conditioning circuit board. The first input end of the second circulator serves as the input end of the mirror main path. The output end of the mirror resonator is connected to the second input end of the second circulator. The output end of the second circulator is connected to the input end of the second low-noise amplifier. The output end of the second low-noise amplifier is connected to the first input end of the second directional coupler. The output end of the second attenuator is connected to the second input end of the second directional coupler. The output end of the second directional coupler is connected to the input end of the second detector. The output end of the second detector is connected to the input end of the second signal conditioning circuit board. The output end of the second signal conditioning circuit board is used to output a noise reference signal. The mirror reference path includes a second phase shifter and a second attenuator. The input end of the second phase shifter is the input end of the mirror reference path. The output end of the second phase shifter is connected to the input end of the second attenuator.

[0039] See Figure 1 , the mirror reference path includes a second phase shifter and a second attenuator. The mirror main path is provided with a mirror modulation field device, a second low-noise amplifier, a second directional coupler, a second detector, and a second signal conditioning circuit board. Among them, the second signal conditioning circuit board has two output ends. The first output end of the second signal conditioning circuit board is connected to an oscilloscope to display the mirror main path tuning curve through the oscilloscope. The second output end of the second signal conditioning circuit board is connected to the input end of a lock-in amplifier to transmit the noise reference signal to the lock-in amplifier.

[0040] In an embodiment of the present invention, the mirror modulation field device includes a mirror resonator. Among them, modulation coils are arranged around the mirror resonator. In the embodiment of the present invention, a medium is added into the mirror resonator, and the resonance frequency of the resonator is changed by changing the depth length of the medium in the mirror resonator. As an example, a frequency modulation component is inserted into the mirror resonator. The frequency modulation component includes a medium and a differential head. The depth of the medium in the mirror resonator is adjusted by adjusting the differential head, so as to adjust the frequency generated in the mirror resonator.

[0041] It should be noted that in order to accurately replicate the noise transmission process in the microwave link by the noise mirror link. On the one hand, it is necessary to keep the properties of the components, cables, resonators, etc. in the noise mirror link as consistent as possible with those in the microwave link. For example, two resonators of the same batch need to be used as the sample resonator and the mirror resonator respectively. On the other hand, it is necessary to accurately adjust the resonant frequency of the mirror resonator in the mirror main path of the noise mirror link and the phase of the second phase shifter on the mirror reference path. Among them, when changing the resonant frequency of the mirror resonator, the resonant frequency of the resonator can be changed by adjusting the depth length of the medium in the mirror resonator, so that the mirror resonator generates the same frequency as the sample resonant frequency.

[0042] It should be noted that there are two sources of noise at the detector. One is the noise transmitted from the phase noise of the wave source to the detector through the main path including the sample resonator, and the other is the noise transmitted from the phase noise of the wave source to the detector through the reference path. In the embodiments of the present invention, the purpose of the reference path and the mirror reference path is to provide a phase reference for the detector to detect the wave, and to provide a bias for the detector to detect the wave so that it works in the best linear region. In order to ensure the phase consistency between the reference path and the main path, phase shifters are added to the reference path and the mirror reference path to adjust the phase. In order to ensure that the bias power is appropriate, attenuators are added to the reference path and the mirror reference path.

[0043] The electron paramagnetic resonance spectrometer in the embodiments of the present invention adds a noise mirror link mirroring the microwave link. The noise mirror link replicates the transmission process of phase noise in two paths (the main path and the reference path) in the microwave link and establishes a noise reference for the microwave link.

[0044] The present invention provides a noise suppression method based on an electron paramagnetic resonance spectrometer.

[0045] The noise suppression method in the embodiments of the present invention is used for an electron paramagnetic resonance spectrometer.

[0046] The electron paramagnetic resonance spectrometer in the embodiments of the present invention may include a microwave link and a noise mirror link mirroring the microwave link.

[0047] Figure 2 It is a flowchart of the noise suppression method according to an embodiment of the present invention. As Figure 2 shown, the noise suppression method based on an electron paramagnetic resonance spectrometer may include:

[0048] S101, obtaining a sample path signal generated by the microwave link and a noise reference signal generated by the noise mirror link;

[0049] S102, performing noise reduction processing on the sample path signal by using the noise reference signal to obtain a denoised target sample path signal.

[0050] To improve the signal-to-noise ratio of an electron paramagnetic resonance spectrometer and effectively reduce the influence of the noise generated by the electron paramagnetic resonance spectrometer on the paramagnetic resonance spectrum of a sample to be measured. In an embodiment of the present invention, a noise reference signal generated by a noise mirror link is used to denoise a sample path signal generated by a microwave link, and the paramagnetic resonance spectrum of the sample to be measured is determined using the target sample path signal obtained after denoising.

[0051] In a specific embodiment of the present invention, as Figure 3 shown, using the noise reference signal to denoise the sample path signal to obtain the denoised target sample path signal may include:

[0052] S201, demodulating the sample path signal and the noise reference signal respectively through a lock-in amplifier to obtain a sample path signal sequence and a noise reference signal sequence;

[0053] S202, statistically analyzing the sample path signal sequence and the noise reference signal sequence within a preset time period to obtain a first statistic and a second statistic, where the preset time period is a time period taken during the period when the electron paramagnetic resonance spectrometer generates a full-noise signal;

[0054] S203, obtaining the target sample path signal according to the first statistic, the second statistic, the sample path signal sequence, and the noise reference signal sequence.

[0055] Specifically, the lock-in amplifier is used to demodulate the sample path signal generated by the microwave link and the noise reference signal generated by the noise mirror link respectively to obtain a sample path signal sequence and a noise reference signal sequence. The sample path signal sequence within a preset time period during the period when the electron paramagnetic resonance spectrometer generates a full-noise signal is statistically analyzed to calculate the mean and standard deviation of the sample path signal sequence within the preset time to obtain the first statistic (sample path mean and sample path standard deviation). The noise reference signal sequence within a preset time period during the period when the electron paramagnetic resonance spectrometer generates a full-noise signal is statistically analyzed to calculate the mean and standard deviation of the noise reference signal sequence within the preset time to obtain the second statistic (mirror path mean and mirror path standard deviation). The target sample path signal is obtained according to the sample path mean, the sample path standard deviation, the mirror path mean, the mirror path standard deviation, the sample path signal sequence, and the noise reference signal sequence.

[0056] In a specific embodiment of the present invention, as Figure 4 shown, the first statistic includes a sample path mean and a sample path standard deviation, the second statistic includes a mirror path mean and a mirror path standard deviation, and obtaining the target sample path signal according to the first statistic, the second statistic, the sample path signal sequence, and the noise reference signal sequence may include:

[0057] S301. Subtract the sample path signal in the sample path signal sequence from the sample path mean to obtain a first difference signal sequence;

[0058] S302. Subtract the noise reference signal in the noise reference signal sequence from the mirror path mean to obtain a second difference signal sequence, and multiply the second difference signal in the second difference signal sequence by the ratio of the sample path standard deviation to the mirror path standard deviation to obtain a product signal sequence;

[0059] S303. Subtract the product signal in the product signal sequence from the first difference signal in the first difference signal sequence to obtain the target sample path signal.

[0060] Specifically, denote the demodulated sample path signal sequence as s 样本 , the noise reference signal sequence as s 镜像 , and the sample path signal sequence s 样本 within the preset time period when no "useful EPR signal" is generated (i.e., all the signals collected at this time are noise) calculated from the noise reference signal sequence s 镜像 mean μ 样本 of the noise, μ 镜像 and standard deviation σ 样本 of the noise, σ 镜像 .

[0061] Subtract the sample path signal s 样本 in the sample path signal sequence from the sample path mean μ 样本 to obtain a first difference signal sequence. Subtract the noise reference signal s 镜像 in the noise reference signal sequence from the mirror path mean μ 镜像 to obtain a second difference signal sequence. Calculate the ratio of the sample path standard deviation to the mirror path standard deviation, and multiply the second difference signal in the second difference signal sequence by this ratio to obtain a product signal sequence. Subtract the product signal in the product signal sequence from the first difference signal in the first difference signal sequence to obtain the target sample path signal.

[0062] In a specific embodiment of the present invention, the calculation method for noise suppression is:

[0063] s 去噪 = s 样本 - μ 样本 - (s 镜像 - μ 镜像 )·σ 样本 / σ 镜像

[0064] where s 去噪 represents the electron paramagnetic resonance spectrum of the sample to be measured, s 样本represents the sample path signal sequence, μ 样本 represents the sample path mean, σ 样本 represents the sample path standard deviation, s 镜像 represents the noise reference signal sequence, μ 镜像 represents the mirror path mean, σ 镜像 represents the mirror path standard deviation.

[0065] Figure 5 shows the waveform comparison diagram of the sample path signal, the noise reference signal, and the target sample path signal obtained after noise reduction processing in the embodiment of the present invention. From Figure 5 it can be observed that the noise waveforms of the sample path and the mirror path are correlated.

[0066] Among them, in the EPR experiment, the noise suppression effect of the embodiment of the present invention is as Figure 6 shown. The noise suppression effect at different powers is as Figure 7 shown. From Figure 7 it can be seen that at different powers, the embodiment of the present invention can suppress the noise to about half of the original.

[0067] The noise suppression method of the embodiment of the present invention performs noise reduction processing on the sample path signal generated by the microwave link based on the noise reference signal generated by the noise mirror link in the electron paramagnetic resonance spectrometer, and determines the electron paramagnetic resonance spectrum of the sample to be measured by using the target sample path signal obtained after denoising, effectively improving the signal-to-noise ratio of the EPR spectrometer.

[0068] In a specific embodiment of the present invention, the microwave link includes a main path and a reference path, the noise mirror link includes a mirror main path and a mirror reference path, and the electron paramagnetic resonance spectrometer further includes a microwave source, a power amplifier, a first power splitter, a main path attenuator, a second power splitter, and a third power splitter. The output end of the microwave source is connected to the input end of the power amplifier, the output end of the power amplifier is connected to the input end of the first power splitter, the first output end of the first power splitter is connected to the input end of the second power splitter, the first output end of the second power splitter is connected to the input end of the reference path, the second output end of the second power splitter is connected to the input end of the mirror reference path, the second output end of the first power splitter is connected to the input end of the main path attenuator, the output end of the main path attenuator is connected to the input end of the third power splitter, the first output end of the third power splitter is connected to the input end of the main path, and the second output end of the third power splitter is connected to the input end of the mirror main path.

[0069] Among them, before obtaining the sample path signal generated by the microwave link and the noise reference signal generated by the noise mirror link, the method further includes:

[0070] Control the microwave source to generate a microwave signal with the same frequency as the sample resonance frequency of the sample to be measured, and tune the microwave link and the noise mirror link.

[0071] Specifically, before obtaining the sample path signal generated by the microwave link and the noise reference signal generated by the noise mirror link, control the microwave source to generate a microwave signal with the same frequency as the sample resonance frequency of the sample to be measured, and tune the microwave link and the noise mirror link.

[0072] Implementable, after the sample to be measured is inserted into the sample resonance cavity, make the host computer software switch to the tuning mode, display the sample path signal generated by the microwave link and the noise reference signal generated by the noise mirror link on the oscilloscope respectively, and generate the main path tuning curve and the mirror main path tuning curve. Comparing with the main path tuning curve, adjust the frequency of the microwave signal generated by the microwave source to the resonance frequency of the sample resonance cavity (i.e., the frequency corresponding to the lowest point of the tuning curve).

[0073] In a specific embodiment of the present invention, the main path includes a main modulation field device for providing a main modulation field to the sample to be measured. The main modulation field device includes a sample resonance cavity and a first circulator. The main path further includes a first low-noise amplifier, a first directional coupler, a first detector, and a first signal conditioning circuit board. The first input end of the first circulator is the input end of the main path. The output end of the sample resonance cavity is connected to the second input end of the first circulator. The output end of the first circulator is connected to the input end of the first low-noise amplifier. The output end of the first low-noise amplifier is connected to the first input end of the first directional coupler. The output end of the first attenuator is connected to the second input end of the first directional coupler. The output end of the first directional coupler is connected to the input end of the first detector. The output end of the first detector is connected to the input end of the first signal conditioning circuit board. The output end of the first signal conditioning circuit board is used to output the sample path signal;

[0074] The reference path includes a first phase shifter and a first attenuator. The input end of the first phase shifter is the input end of the reference path. The output end of the first phase shifter is connected to the input end of the first attenuator.

[0075] In a specific embodiment of the present invention, the mirror main path includes a mirror modulation field device for providing a mirror modulation field. The mirror modulation field device includes a mirror resonator and a second circulator. The mirror main path includes a second low-noise amplifier, a second directional coupler, a second detector, and a second signal conditioning circuit board. The first input end of the second circulator serves as the input end of the mirror main path. The output end of the mirror resonator is connected to the second input end of the second circulator. The output end of the second circulator is connected to the input end of the second low-noise amplifier. The output end of the second low-noise amplifier is connected to the first input end of the second directional coupler. The output end of the second attenuator is connected to the second input end of the second directional coupler. The output end of the second directional coupler is connected to the input end of the second detector. The output end of the second detector is connected to the input end of the second signal conditioning circuit board. The output end of the second signal conditioning circuit board is used to output a noise reference signal;

[0076] The mirror reference path includes a second phase shifter and a second attenuator. The input end of the second phase shifter is the input end of the mirror reference path. The output end of the second phase shifter is connected to the input end of the second attenuator.

[0077] In a specific embodiment of the present invention, tuning the microwave link and the noise mirror link may include:

[0078] Adjust the first attenuator to make the attenuation value of the first attenuator reach the maximum;

[0079] Adjust the attenuation value of the main path attenuator to a first preset attenuation value, and adjust the resonant rod of the sample resonator so that the lowest point of the main path tuning curve reaches a first target value;

[0080] Adjust the resonant frequency of the mirror resonator to the sample resonant frequency according to the sample resonant frequency, and adjust the second attenuator to make the attenuation value of the second attenuator reach the maximum.

[0081] Specifically, before tuning the microwave signal frequency generated by the microwave source to the resonant frequency of the sample resonator, the attenuation value of the first attenuator in the reference path should be adjusted to the maximum to record the sample resonant frequency f0 at this time.

[0082] Adjust the attenuation value of the main path attenuator. If the dip (lowest point) of the tuning curve of the sample path does not reach 0V (the first target value) at this time, continue to adjust the tuning rod to adjust the dip of the main path tuning curve to 0V (if it cannot be adjusted to 0, make it as low as possible), and record the attenuation value of the main path attenuator at this time (which can be recorded as the first preset attenuation value). Thus, the sample resonator reaches critical coupling, at which time the sample resonator is the lowest and the microwave power leakage is the least.

[0083] After adjusting the attenuation value of the second attenuator in the mirror reference path to the maximum, adjust the mirror resonator frequency according to the sample resonance frequency to make the mirror resonator frequency consistent with the sample resonator frequency. Among them, making the reference cavity resonance frequency consistent with the sample resonator can increase the correlation of the noise collected by the mirror path and the sample path.

[0084] In an embodiment of the present invention, the first target value is 0V.

[0085] In a specific embodiment of the present invention, adjust the attenuation value of the main path attenuator to the maximum, and adjust the attenuation value of the first attenuator to make the lowest point of the main path tuning curve reach the second target value, where the second target value is greater than the first target value;

[0086] Adjust the attenuation value of the main path attenuator to the first preset attenuation value, and adjust the first phase shifter to make the resonance frequency of the main path return to the sample resonance frequency.

[0087] Specifically, adjust the attenuation value of the main path attenuator to the maximum, and adjust the attenuation value of the first attenuator on the reference path in the sample path to make the dip (lowest point) of the sample path tuning curve (main path tuning curve) reach 0.5V (second target value). Then adjust the main path attenuator to the first preset attenuation value. Adjust the first phase shifter on the reference path to make the resonance frequency of the main path return to the recorded sample resonance frequency f0. Based on the above adjustment, the microwave link outputs the sample path signal for noise suppression.

[0088] In an embodiment of the present invention, the second target value is 0.5V.

[0089] In a specific embodiment of the present invention, adjust the attenuation value of the main path attenuator to the maximum, and adjust the attenuation value of the second attenuator to make the lowest point of the mirror main path tuning curve reach the second target value;

[0090] Adjust the attenuation value of the main path attenuator to the first preset attenuation value, and adjust the second phase shifter to make the resonance frequency of the mirror main path return to the sample resonance frequency.

[0091] Specifically, adjust the attenuation value of the main path attenuator to the maximum, and adjust the attenuation value of the second attenuator on the mirror reference path of the mirror path to make the dip lowest point of the mirror main path tuning curve reach 0.5V (second target value). Then adjust the attenuation value of the main path attenuator to the first preset attenuation value. Adjust the second phase shifter on the mirror reference path to make the resonance frequency of the mirror main path return to the recorded sample resonance frequency f0. After the adjustment is completed, turn off the tuning mode. Based on the above adjustment, the noise mirror link outputs the noise reference signal for noise suppression.

[0092] After the adjustment is completed, it is observed that the noise waveforms of the sample path and the mirror path are correlated. SeeFigure 5 Accordingly, the part related to the noise of the mirror path can be removed from the noise of the sample path. After starting the EPR experiment, the noise in the sample path signal is suppressed according to the noise reference signal to improve the signal-to-noise ratio of EPR.

[0093] Before performing noise suppression in the embodiments of the present invention, the sample path signal generated by the microwave link in the electron paramagnetic resonance spectrometer and the noise reference signal generated by the noise mirror link are tuned to improve the correlation between the sample path signal and the noise reference signal, and then the noise reference signal obtained after tuning is used to suppress the noise of the sample path signal obtained after tuning, effectively improving the signal-to-noise ratio of EPR.

[0094] The present invention provides a mirror tuning method based on an electron paramagnetic resonance spectrometer.

[0095] The mirror tuning method of the embodiments of the present invention is used for an electron paramagnetic resonance spectrometer.

[0096] The electron paramagnetic resonance spectrometer in the embodiments of the present invention includes a microwave source, a microwave link, and a noise mirror link that mirrors the microwave link. The microwave link includes a main path and a reference path, the noise mirror link includes a mirror main path and a mirror reference path, and the microwave source is respectively connected to the main path, the reference path, the mirror main path, and the mirror reference path.

[0097] Figure 8 is a flowchart of the mirror tuning method of an embodiment of the present invention. As Figure 8 shown, the mirror tuning method may include:

[0098] S401, obtaining the sample path signal generated by the microwave link and the noise reference signal generated by the noise mirror link, generating a main path tuning curve according to the sample path signal, and generating a mirror main path tuning curve according to the noise reference signal;

[0099] S402, controlling the microwave source to generate a microwave signal with a frequency the same as the sample resonance frequency of the sample to be measured in the sample resonator on the main path according to the main path tuning curve;

[0100] S403, adjusting the frequency of the sample resonator and the reference path according to the main path tuning curve, adjusting the frequency of the mirror resonator on the mirror main path according to the frequency of the sample resonator, and adjusting the mirror reference path according to the mirror main path tuning curve.

[0101] To improve the correlation between the sample path signal and the noise reference signal, the sample path signal generated by the microwave link and the noise reference signal generated by the noise mirror link are tuned.

[0102] Specifically, after the sample to be measured is inserted into the sample resonator, the host computer software is switched to the tuning mode. When mirror tuning the microwave link and the noise mirror link, the sample path signal generated by the microwave link and the noise reference signal generated by the noise mirror link are respectively displayed on the oscilloscope to generate the main path tuning curve and the mirror main path tuning curve. Comparing with the main path tuning curve, the frequency generated by the microwave source is adjusted so that the microwave source generates a microwave signal with the same sample resonance frequency as the sample to be measured in the sample resonator on the main path. The frequency and reference path of the sample resonator are adjusted according to the main path tuning curve. The frequency of the mirror resonator on the mirror main path is adjusted according to the frequency of the sample resonator so that the frequency of the mirror resonator is consistent with the frequency of the sample resonator, and the mirror reference path is adjusted according to the mirror main path tuning curve.

[0103] In a specific embodiment of the present invention, the electron paramagnetic resonance spectrometer further includes a power amplifier, a first power splitter, a main path attenuator, a second power splitter, and a third power splitter. The output end of the microwave source is connected to the input end of the power amplifier, the output end of the power amplifier is connected to the input end of the first power splitter, the first output end of the first power splitter is connected to the input end of the second power splitter, the first output end of the second power splitter is connected to the input end of the reference path, the second output end of the second power splitter is connected to the input end of the mirror reference path, the second output end of the first power splitter is connected to the input end of the main path attenuator, the output end of the main path attenuator is connected to the input end of the third power splitter, the first output end of the third power splitter is connected to the input end of the main path, and the second output end of the third power splitter is connected to the input end of the mirror main path; wherein, adjusting the frequency of the sample resonator according to the main path tuning curve may include:

[0104] Adjust the attenuation value of the main path attenuator to a first preset attenuation value, and adjust the resonance rod of the sample resonator so that the lowest point of the main path tuning curve reaches a first target value.

[0105] Implementable, adjust the attenuation value of the main path attenuator. If the dip (lowest point) of the tuning curve of the sample path does not reach 0V (the first target value) at this time, continue to adjust the tuning rod to adjust the dip of the tuning curve of the sample path to 0V (if it cannot be adjusted to 0, make it as low as possible), and record the attenuation value of the main path attenuator at this time (which can be recorded as the first preset attenuation value). Thus, the sample resonator reaches critical coupling, at which time the sample resonator is the lowest and the microwave power leakage is the least.

[0106] In a specific embodiment of the present invention, the main path includes a main modulation field device for providing a main modulation field to the sample to be measured. The main modulation field device includes a sample resonator and a first circulator. The main path further includes a first low-noise amplifier, a first directional coupler, a first detector, and a first signal conditioning circuit board. The first input end of the first circulator is the input end of the main path. The output end of the sample resonator is connected to the second input end of the first circulator. The output end of the first circulator is connected to the input end of the first low-noise amplifier. The output end of the first low-noise amplifier is connected to the first input end of the first directional coupler. The output end of the first attenuator is connected to the second input end of the first directional coupler. The output end of the first directional coupler is connected to the input end of the first detector. The output end of the first detector is connected to the input end of the first signal conditioning circuit board. The output end of the first signal conditioning circuit board is connected to the input end of the lock-in amplifier. The reference path includes a first phase shifter and a first attenuator. The input end of the first phase shifter is the input end of the reference path. The output end of the first phase shifter is connected to the input end of the first attenuator. Wherein, before controlling the microwave source to generate a microwave signal with a frequency equal to the sample resonance frequency, the attenuation value of the first attenuator is adjusted to the maximum.

[0107] In an embodiment of the present invention, before tuning the frequency of the microwave signal generated by the microwave source to the resonance frequency of the sample resonator, the attenuation value of the first attenuator in the reference path should be adjusted to the maximum. That is, after the attenuation value of the first attenuator in the reference path is adjusted to the maximum, the frequency of the microwave signal generated by the microwave source is tuned to the resonance frequency of the sample resonator according to the main path tuning curve, and the sample resonance frequency f0 at this time is recorded.

[0108] In a specific embodiment of the present invention, the mirror main path includes a mirror modulation field device for providing a mirror modulation field. The mirror modulation field device includes a mirror resonator and a second circulator. The mirror main path includes a second low-noise amplifier, a second directional coupler, a second detector, and a second signal conditioning circuit board. The first input end of the second circulator serves as the input end of the mirror main path. The output end of the mirror resonator is connected to the second input end of the second circulator. The output end of the second circulator is connected to the input end of the second low-noise amplifier. The output end of the second low-noise amplifier is connected to the first input end of the second directional coupler. The output end of the second attenuator is connected to the second input end of the second directional coupler. The output end of the second directional coupler is connected to the input end of the second detector. The output end of the second detector is connected to the input end of the second signal conditioning circuit board. The output end of the second signal conditioning circuit board is connected to the input end of the lock-in amplifier. The mirror reference path includes a second phase shifter and a second attenuator. The input end of the second phase shifter is the input end of the mirror reference path. The output end of the second phase shifter is connected to the input end of the second attenuator. Before adjusting the frequency of the mirror resonator on the mirror main path according to the frequency of the sample resonator, the attenuation value of the second attenuator is adjusted to the maximum.

[0109] In an embodiment of the present invention, before adjusting the frequency of the mirror resonator on the mirror main path according to the frequency of the sample resonator, the attenuation value of the second attenuator in the mirror reference path should be adjusted to the maximum. That is, after the attenuation value of the second attenuator in the mirror reference path is adjusted to the maximum, the frequency of the mirror resonator on the mirror main path is adjusted according to the frequency of the sample resonator, so that the frequency of the mirror resonator on the mirror main path is adjusted to the resonant frequency of the sample resonator.

[0110] In a specific embodiment of the present invention, adjusting the reference path according to the main path tuning curve includes:

[0111] Adjusting the attenuation value of the main path attenuator to the maximum and adjusting the attenuation value of the first attenuator so that the lowest point of the main path tuning curve reaches a second target value, where the second target value is greater than the first target value;

[0112] Adjusting the attenuation value of the main path attenuator to a first preset attenuation value and adjusting the first phase shifter so that the resonant frequency of the main path returns to the sample resonant frequency.

[0113] Specifically, adjust the attenuation value of the main path attenuator to the maximum, and adjust the attenuation value of the first attenuator on the reference path in the sample path so that the dip (lowest point) of the sample path tuning curve (main path tuning curve) reaches 0.5 V (the second target value). Then adjust the main path attenuator to the first preset attenuation value. Adjust the first phase shifter on the reference path so that the resonant frequency of the main path returns to the sample resonant frequency f0. Based on the above adjustments, the microwave link outputs the sample path signal for noise suppression.

[0114] In an embodiment of the present invention, the second target value is 0.5 V.

[0115] In a specific embodiment of the present invention, adjusting the mirror reference path according to the mirror main path tuning curve includes:

[0116] Adjust the attenuation value of the main path attenuator to the maximum, and adjust the attenuation value of the second attenuator so that the lowest point of the mirror main path tuning curve reaches the second target value;

[0117] Adjust the attenuation value of the main path attenuator to the first preset attenuation value, and adjust the second phase shifter so that the resonant frequency of the mirror main path returns to the sample resonant frequency.

[0118] Specifically, adjust the attenuation value of the main path attenuator to the maximum, and adjust the attenuation value of the second attenuator on the mirror reference path of the mirror path so that the dip lowest point of the mirror main path tuning curve reaches 0.5 V (the second target value). Then adjust the attenuation value of the main path attenuator to the first preset attenuation value. Adjust the second phase shifter on the mirror reference path so that the resonant frequency of the mirror main path returns to the sample resonant frequency f0. After the adjustment is completed, turn off the tuning mode. Based on the above adjustments, the noise mirror link outputs the noise reference signal for noise suppression.

[0119] After the adjustment is completed, turn off the tuning mode. It is observed that the noise waveforms of the sample path and the mirror path are correlated, see Figure 5 . Accordingly, the part of the noise in the sample path that is correlated with the noise in the mirror path can be removed. After starting the EPR experiment, suppress the noise in the sample path signal according to the noise reference signal to improve the signal-to-noise ratio of EPR.

[0120] In a specific embodiment of the present invention, after the microwave link and the noise mirror link are adjusted, the method includes:

[0121] Demodulate the sample path signal and the noise reference signal respectively through a lock-in amplifier to obtain a sample path signal sequence and a noise reference signal sequence;

[0122] Statistically analyze the sample path signal sequence and the noise reference signal sequence within a preset time period to obtain a first statistic and a second statistic, where the preset time period is a time period taken during the generation of a full-noise signal by an electron paramagnetic resonance spectrometer;

[0123] Obtain the target sample path signal based on the first statistic, the second statistic, the sample path signal sequence, and the noise reference signal sequence.

[0124] Specifically, during an EPR experiment, a lock-in amplifier is used to demodulate the sample path signal generated by the microwave link and the noise reference signal generated by the noise mirror link respectively to obtain the sample path signal sequence and the noise reference signal sequence. Statistically analyze the sample path signal sequence within the preset time period during the generation of a full-noise signal by the electron paramagnetic resonance spectrometer to calculate the mean and standard deviation of the sample path signal sequence within the preset time, and obtain the first statistic (sample path mean and sample path standard deviation). Statistically analyze the noise reference signal sequence within the preset time period during the generation of a full-noise signal by the electron paramagnetic resonance spectrometer to calculate the mean and standard deviation of the noise reference signal sequence within the preset time, and obtain the second statistic (mirror path mean and mirror path standard deviation). Obtain the target sample path signal based on the first statistic, the second statistic, the sample path signal sequence, and the noise reference signal sequence.

[0125] In a specific embodiment of the present invention, the first statistic includes the sample path mean and the sample path standard deviation, and the second statistic includes the mirror path mean and the mirror path standard deviation. Obtaining the target sample path signal based on the first statistic, the second statistic, the sample path signal sequence, and the noise reference signal sequence includes:

[0126] Subtract the sample path signal in the sample path signal sequence from the sample path mean to obtain a first difference signal sequence;

[0127] Subtract the noise reference signal in the noise reference signal sequence from the mirror path mean to obtain a second difference signal sequence, and multiply the second difference signal in the second difference signal sequence by the ratio of the sample path standard deviation to the mirror path standard deviation to obtain a product value signal sequence;

[0128] Subtract the product value signal in the product value signal sequence from the first difference signal in the first difference signal sequence to obtain the electron paramagnetic resonance spectrum of the sample to be measured.

[0129] Specifically, denote the demodulated sample path signal sequence as s 样本 , and the noise reference signal sequence as s 镜像 , and calculate the sample path signal sequence s within the preset time of the period without generating an "EPR useful signal" (i.e., all noise is collected at this time)样本 with the noise reference signal sequence s 镜像 the mean μ of the noise 样本 and μ 镜像 and the standard deviation σ 样本 and σ 镜像 .

[0130] Subtract the sample path signal s in the sample path signal sequence 样本 from the sample path mean μ 样本 to obtain a first difference signal sequence. Subtract the noise reference signal s in the noise reference signal sequence 镜像 from the mirror path mean μ 镜像 to obtain a second difference signal sequence. Calculate the ratio of the sample path standard deviation to the mirror path standard deviation, and multiply the second difference signal in the second difference signal sequence by this ratio to obtain a product signal sequence. Subtract the first difference signal in the first difference signal sequence from the product signal in the product signal sequence to obtain the target sample path signal.

[0131] Among them, in the EPR experiment, the noise suppression effect of the embodiment of the present invention is as Figure 6 shown. The noise suppression effect at different powers is as Figure 7 shown. It can be seen from Figure 7 that at different powers, the embodiment of the present invention can suppress the noise to about half of the original.

[0132] The mirror tuning method of the embodiment of the present invention tunes the sample path signal generated by the microwave link in the electron paramagnetic resonance spectrometer and the noise reference signal generated by the noise mirror link, improves the correlation between the sample path signal and the noise reference signal, so as to further improve the noise suppression effect of the sample path signal according to the noise reference signal, and effectively improves the signal-to-noise ratio of EPR.

[0133] The present invention provides a computer-readable storage medium.

[0134] In this embodiment, a computer program is stored on the computer-readable storage medium. When the computer program is executed by a processor, the mirror tuning method as described above is implemented.

[0135] The present invention provides a controller.

[0136] In this embodiment, the controller includes a memory and a processor. A computer program is stored on the memory. When the computer program is executed by the processor, the mirror tuning method as described above is implemented.

[0137] Figure 9 is the structural block diagram of the controller of the embodiment of the present invention.

[0138] As Figure 9As shown, the controller 500 includes: a processor 501 and a memory 503. Among them, the processor 501 and the memory 503 are connected, such as connected through a bus 502. Optionally, the controller 500 may further include a transceiver 504. It should be noted that in practical applications, the transceiver 504 is not limited to one, and the structure of this controller 500 does not constitute a limitation on the embodiments of the present invention.

[0139] The processor 501 may be a CPU (Central Processing Unit), a general-purpose processor, a DSP (Digital Signal Processor), an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. It can implement or execute various exemplary logic blocks, modules, and circuits described in connection with the disclosure of the present invention. The processor 501 may also be a combination that implements computing functions, such as a combination including one or more microprocessors, a combination of a DSP and a microprocessor, etc.

[0140] The bus 502 may include a path for transmitting information between the above components. The bus 502 may be a PCI (Peripheral Component Interconnect) bus or an EISA (Extended Industry Standard Architecture) bus, etc. The bus 502 may be divided into an address bus, a data bus, a control bus, etc. For the sake of representation, Figure 9 only a thick line is shown in the figure, but it does not mean that there is only one bus or one type of bus.

[0141] The memory 503 is used to store a computer program corresponding to the mirror tuning method of the above embodiments of the present invention, and this computer program is controlled and executed by the processor 501. The processor 501 is used to execute the computer program stored in the memory 503 to implement the content shown in the foregoing method embodiments. Figure 9 The shown controller 500 is only an example and should not bring any limitation to the functions and usage scope of the embodiments of the present invention.

[0142] The computer-readable storage medium and controller of the embodiments of the present invention utilize the above mirror tuning method to improve the correlation between the sample path signal and the noise reference signal, further improve the effect of noise suppression on the sample path signal according to the noise reference signal, and effectively improve the signal-to-noise ratio of EPR.

[0143] It should be noted that the logic and / or steps represented in the flowchart or described in other ways herein, for example, can be considered as a definite sequence list of executable instructions for implementing logical functions, and can be specifically implemented in any computer-readable medium for use by an instruction execution system, apparatus or device (such as a computer-based system, a system including a processor, or other systems that can fetch instructions from the instruction execution system, apparatus or device and execute the instructions), or in combination with these instruction execution systems, apparatus or devices. For the purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate or transport a program for use by or in combination with an instruction execution system, apparatus or device. More specific examples (a non-exhaustive list) of the computer-readable medium include the following: an electrical connection portion with one or more wirings (electronic device), a portable computer diskette (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disc read-only memory (CDROM). Additionally, the computer-readable medium can even be paper or other suitable media on which the program can be printed, because the program can be obtained electronically, for example, by optically scanning the paper or other media, followed by editing, interpretation or, if necessary, other suitable processing, and then stored in a computer memory.

[0144] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-described embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, any one or a combination of the following techniques well known in the art can be used: discrete logic circuits having logic gate circuits for implementing logical functions on data signals, application specific integrated circuits having appropriate combinational logic gate circuits, programmable gate arrays (PGAs), field programmable gate arrays (FPGAs), etc.

[0145] In the description of this specification, the description referring to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0146] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present invention.

[0147] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise specifically and clearly defined.

[0148] In the present invention, unless otherwise clearly defined and limited, the terms "mounted", "connected", "coupled", "fixed", etc. shall be construed in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal communication of two elements or the interaction relationship between two elements, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0149] In the present invention, unless otherwise clearly defined and limited, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may be that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "beneath" and "underneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.

[0150] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A mirror tuning method based on an electron paramagnetic resonance spectrometer, characterized in that The electron paramagnetic resonance spectrometer includes a microwave source, a microwave link, and a noise mirror link that mirrors the microwave link. The microwave link includes a main path and a reference path, and the noise mirror link includes a mirror main path and a mirror reference path. The microwave source is connected to the main path, the reference path, the mirror main path, and the mirror reference path respectively. The method includes: Obtaining a sample path signal generated by the microwave link and a noise reference signal generated by the noise mirror link, generating a main path tuning curve according to the sample path signal, and generating a mirror main path tuning curve according to the noise reference signal; Controlling the microwave source to generate a microwave signal with a frequency identical to the sample resonance frequency of the sample to be measured in the sample resonator on the main path according to the main path tuning curve; Adjusting the frequency of the sample resonator and the reference path according to the main path tuning curve, adjusting the frequency of the mirror resonator on the mirror main path according to the frequency of the sample resonator, and adjusting the mirror reference path according to the mirror main path tuning curve.

2. The mirror tuning method according to claim 1, wherein The electron paramagnetic resonance spectrometer further includes a power amplifier, a first power splitter, a main path attenuator, a second power splitter, and a third power splitter. The output end of the microwave source is connected to the input end of the power amplifier. The output end of the power amplifier is connected to the input end of the first power splitter. The first output end of the first power splitter is connected to the input end of the second power splitter. The first output end of the second power splitter is connected to the input end of the reference path. The second output end of the second power splitter is connected to the input end of the mirror reference path. The second output end of the first power splitter is connected to the input end of the main path attenuator. The output end of the main path attenuator is connected to the input end of the third power splitter. The first output end of the third power splitter is connected to the input end of the main path. The second output end of the third power splitter is connected to the input end of the mirror main path; Wherein, the adjusting the frequency of the sample resonator according to the main path tuning curve includes: Adjusting the attenuation value of the main path attenuator to a first preset attenuation value, and adjusting the resonance rod of the sample resonator so that the lowest point of the main path tuning curve reaches a first target value.

3. The mirror tuning method according to claim 2, wherein The main path includes a main modulation field device for providing the main modulation field to the sample to be measured. The main modulation field device includes a sample resonator and a first circulator. The reference path includes a first phase shifter and a first attenuator. The input end of the first phase shifter is the input end of the reference path. The output end of the first phase shifter is connected to the input end of the first attenuator; The main path further includes a first low-noise amplifier, a first directional coupler, a first detector, and a first signal conditioning circuit board. The first input end of the first circulator is the input end of the main path. The output end of the sample resonator is connected to the second input end of the first circulator. The output end of the first circulator is connected to the input end of the first low-noise amplifier. The output end of the first low-noise amplifier is connected to the first input end of the first directional coupler. The output end of the first attenuator is connected to the second input end of the first directional coupler. The output end of the first directional coupler is connected to the input end of the first detector. The output end of the first detector is connected to the input end of the first signal conditioning circuit board. The output end of the first signal conditioning circuit board is connected to the input end of the lock-in amplifier; Wherein, before controlling the microwave source to generate a microwave signal with a frequency equal to the sample resonance frequency, the attenuation value of the first attenuator is also adjusted to the maximum.

4. The mirror tuning method according to claim 3, characterized in that, The mirror main path includes a mirror modulation field device for providing the mirror modulation field. The mirror modulation field device includes a mirror resonator and a second circulator. The mirror reference path includes a second phase shifter and a second attenuator. The input end of the second phase shifter is the input end of the mirror reference path. The output end of the second phase shifter is connected to the input end of the second attenuator; The mirror main path further includes a second low-noise amplifier, a second directional coupler, a second detector, and a second signal conditioning circuit board. The first input end of the second circulator serves as the input end of the mirror main path. The output end of the mirror resonator is connected to the second input end of the second circulator. The output end of the second circulator is connected to the input end of the second low-noise amplifier. The output end of the second low-noise amplifier is connected to the first input end of the second directional coupler. The output end of the second attenuator is connected to the second input end of the second directional coupler. The output end of the second directional coupler is connected to the input end of the second detector. The output end of the second detector is connected to the input end of the second signal conditioning circuit board. The output end of the second signal conditioning circuit board is connected to the input end of the lock-in amplifier; Wherein, before adjusting the frequency of the mirror resonator on the mirror main path according to the frequency of the sample resonator, the attenuation value of the second attenuator is also adjusted to the maximum.

5. The mirror tuning method according to claim 4, wherein Adjusting the reference path according to the main path tuning curve includes: Adjusting the attenuation value of the main path attenuator to the maximum and adjusting the attenuation value of the first attenuator so that the lowest point of the main path tuning curve reaches a second target value, where the second target value is greater than the first target value; Adjusting the attenuation value of the main path attenuator to the first preset attenuation value and adjusting the first phase shifter so that the resonance frequency of the main path returns to the sample resonance frequency.

6. The mirror tuning method according to claim 5, characterized in that Adjusting the mirror reference path according to the mirror main path tuning curve includes: Adjust the attenuation value of the main path attenuator to the maximum, and adjust the attenuation value of the second attenuator so that the lowest point of the mirror main path tuning curve reaches the second target value; Adjust the attenuation value of the main path attenuator to the first preset attenuation value, and adjust the second phase shifter so that the resonance frequency of the mirror main path returns to the sample resonance frequency.

7. The mirror tuning method according to claim 1, wherein After the adjustment of the microwave link and the noise mirror link is completed, the method includes: Demodulate the sample path signal and the noise reference signal respectively through a lock-in amplifier to obtain a sample path signal sequence and a noise reference signal sequence; Statistically analyze the sample path signal sequence and the noise reference signal sequence within a preset time period to obtain a first statistic and a second statistic, where the preset time period is a time period taken during the generation of the full noise signal by the electron paramagnetic resonance spectrometer; Obtain a target sample path signal according to the first statistic, the second statistic, the sample path signal sequence and the noise reference signal sequence.

8. The mirror tuning method according to claim 7, wherein The first statistic includes a sample path mean and a sample path standard deviation, and the second statistic includes a mirror path mean and a mirror path standard deviation. Obtaining the target sample path signal according to the first statistic, the second statistic, the sample path signal sequence and the noise reference signal sequence includes: Subtract the sample path signal in the sample path signal sequence from the sample path mean to obtain a first difference signal sequence; Subtract the noise reference signal in the noise reference signal sequence from the mirror path mean to obtain a second difference signal sequence, and multiply the second difference signal in the second difference signal sequence by the ratio of the sample path standard deviation to the mirror path standard deviation to obtain a product value signal sequence; Subtract the product value signal in the product value signal sequence from the first difference signal in the first difference signal sequence to obtain the electron paramagnetic resonance spectrum of the sample to be measured.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the mirror tuning method according to any one of claims 1-8.

10. A controller, comprising a memory and a processor, wherein a computer program is stored on the memory, characterized in that When the computer program is executed by the processor, it implements the mirror tuning method according to any one of claims 1-8.

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