A method for analyzing a ring of oscillation circuit based on physical characteristics of a crystal oscillator

Abstract

The application provides a method for analyzing the oscillation circuit of a crystal oscillator based on physical characteristics of the crystal oscillator, applied to the field of electronic measurement technology, and through synchronous acquisition of the crystal oscillator signal and the environmental interference signal, differential operation of the circuit is used to effectively suppress the common-mode environmental interference, and a differential signal mainly containing the crystal oscillator signal is obtained. The differential signal is subjected to frequency spectrum analysis, the actual performance parameters of the crystal oscillator are extracted, and noise is evaluated at the same time. According to the noise evaluation result, the calibration performance parameters of the crystal oscillator are adaptively adjusted, and performance parameter thresholds more in line with the current environmental noise level are obtained. The actual performance parameters are compared with the adjusted performance parameter thresholds, and whether the oscillation circuit of the crystal oscillator meets the production requirements is judged. Therefore, the application has the beneficial effect of effectively improving the detection efficiency of high-precision electronic measuring instruments and the quality of products leaving the factory under the premise of production cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electronic measurement, and in particular to a method for analyzing the oscillation circuit of a crystal oscillator based on physical characteristics of the crystal oscillator. BACKGROUND

[0002] In the production process of high-precision electronic measuring instruments, the crystal oscillator, as the core frequency reference of the instrument, directly affects the measurement accuracy of the instrument. In order to ensure that each instrument meets the predetermined accuracy standard, the oscillation circuit of the crystal oscillator must be strictly analyzed and detected. Especially in the context of mass production, this analysis and detection need to be completed quickly and efficiently on the production line, while avoiding any form of damage to the crystal oscillator and the instrument it is in.

[0003] However, the actual production line environment is often full of various unfavorable factors. Electromagnetic interference is common, and environmental temperature, humidity, etc. may also fluctuate, which will affect the performance of the crystal oscillator and thus reduce the accuracy of the analysis results. In order to adapt to the production rhythm, the analysis process must be highly automated, the operation must be as simple as possible, and it is best to be seamlessly integrated into the existing production line test system to reduce manual operation and dependence on additional equipment. In addition, considering the characteristics of mass production, cost-effectiveness is also a crucial factor. Under the premise of ensuring analysis accuracy, how to minimize the cost and time of each analysis has become a problem to be solved.

[0004] Currently, there are still many challenges in the non-destructive, rapid oscillation circuit analysis method of the crystal oscillator in high-precision electronic measuring instruments on the production line. How to effectively overcome the influence of environmental noise in a complex production line environment, design a method that can guarantee analysis accuracy, meet the calibration requirements of high-precision instruments, and at the same time meet the needs of rapid detection on the production line, be easily integrated into the existing automated test system, and control the cost of additional equipment and the complexity of operation within an acceptable range, is the key to effectively improving the quality and reliability of high-precision electronic measuring instruments leaving the factory without significantly increasing production costs.

[0005] In view of the above problems, the prior art needs to be improved. SUMMARY

[0006] In view of the above shortcomings of the prior art, the present application provides a method for analyzing the oscillation circuit of a crystal oscillator based on the physical characteristics of the crystal oscillator, which has the beneficial effect of improving the accuracy of the analysis of the oscillation circuit of the crystal oscillator.

[0007] In a first aspect, a method for analyzing the oscillation circuit of a crystal oscillator based on the physical characteristics of the crystal oscillator, the method comprising the steps of:

[0008] S1: acquiring a crystal oscillator signal and an environmental interference signal;

[0009] S2: performing a circuit difference operation on the crystal oscillator signal and the environmental interference signal to obtain a difference signal;

[0010] S3: performing a spectrum analysis on the difference signal to extract an actual performance parameter of the crystal oscillator and obtain a noise evaluation result;

[0011] S4: acquiring a calibrated performance parameter of the crystal oscillator, adaptively adjusting the calibrated performance parameter according to the noise evaluation result to obtain an adjusted performance parameter threshold;

[0012] S5: comparing the actual performance parameter with the performance parameter threshold to determine whether the oscillation circuit of the crystal oscillator meets production requirements and outputting a determination result.

[0013] The oscillation circuit analysis method based on the physical characteristics of the crystal oscillator is proposed to solve the influence of environmental interference on the accuracy of the analysis result. First, step S1 synchronously acquires the crystal oscillator signal and the environmental interference signal to provide a signal basis for the subsequent difference operation. Step S2 uses the circuit difference operation to effectively suppress the common-mode environmental interference to obtain a difference signal mainly containing the crystal oscillator signal. Step S3 performs a spectrum analysis on the difference signal to extract the actual performance parameter of the crystal oscillator and evaluate the noise to provide noise information for the subsequent parameter threshold adjustment. Step S4 adaptively adjusts the calibrated performance parameter of the crystal oscillator according to the noise evaluation result to obtain a performance parameter threshold that is more consistent with the current environmental noise level. Step S5 compares the actual performance parameter with the adjusted performance parameter threshold to determine whether the oscillation circuit of the crystal oscillator meets the production requirements. Through the above steps, the technical solution uses the difference operation to reduce the environmental interference and adaptively adjusts the performance parameter threshold through the noise evaluation result, thereby realizing the accurate analysis of the oscillation circuit of the crystal oscillator under the environmental interference.

[0014] Further, in step S4, the noise evaluation result includes a noise type and a noise intensity corresponding to different noise types; and step S4 includes:

[0015] S41: acquiring a calibrated performance parameter of the crystal oscillator and establishing a mapping relationship model of the calibrated performance parameter of the crystal oscillator and the environmental noise;

[0016] S42: calculating the performance parameter threshold of the crystal oscillator under the current noise type and noise intensity according to the mapping relationship model.

[0017] The application provides an oscillation circuit analysis method based on physical characteristics of a crystal oscillator. The specific content of noise evaluation results is determined, a mapping relationship model is introduced, and a more refined and adaptive performance parameter threshold adjustment method is provided. The method can dynamically adjust the performance parameter threshold according to the actual environmental noise, so that the subsequent performance parameter judgment is more accurate and reliable, the adaptive adjustment strategy is more specific, and the accuracy and environmental adaptability of the crystal oscillator oscillation circuit analysis method are improved. The establishment of the mapping relationship model enables the adjustment of the performance parameter threshold to be no longer a simple fixed value, but to be dynamically adjusted according to the noise environment, so as to more accurately reflect the performance requirements of the crystal oscillator in the actual noise environment.

[0018] Further, the step S41 comprises:

[0019] S411: acquiring the frequency, amplitude and phase of the crystal oscillator in a noise-free experimental environment as the calibration performance parameters;

[0020] S412: collecting historical environmental interference signals of a production line, and dividing the historical environmental interference signals into a plurality of noise types and noise intensities corresponding to different noise types;

[0021] S413: acquiring experimental performance parameters of the crystal oscillator in different noise types in an experimental environment;

[0022] S414: calculating the frequency, amplitude and phase drift difference between the experimental performance parameters and the calibration performance parameters, respectively, determining the influence coefficient of different noise types and noise intensities on the calibration performance parameters according to the drift difference, and establishing the mapping relationship model according to the influence coefficient.

[0023] The application provides an oscillation circuit analysis method based on physical characteristics of a crystal oscillator. The specific content of noise evaluation results is determined, a mapping relationship model is introduced, and a more refined and adaptive performance parameter threshold adjustment method is provided. The method can dynamically adjust the performance parameter threshold according to the actual environmental noise, so that the subsequent performance parameter judgment is more accurate and reliable, the adaptive adjustment strategy is more specific, and the accuracy and environmental adaptability of the crystal oscillator oscillation circuit analysis method are improved. The establishment of the mapping relationship model enables the adjustment of the performance parameter threshold to be no longer a simple fixed value, but to be dynamically adjusted according to the noise environment, so as to more accurately reflect the performance requirements of the crystal oscillator in the actual noise environment.

[0024] Further, in step S414, the mapping relationship model is:

[0025] , wherein, is the adjusted frequency threshold, is an adjusted amplitude threshold value, is an adjusted phase threshold value, the performance parameter threshold value comprises , , ;

[0026] wherein, , , respectively represent the frequency, amplitude and phase of the calibrated performance parameter;

[0027] wherein, , , are the influence coefficient of frequency, amplitude influence coefficient, phase influence coefficient; , is a drift difference of frequency, is a noise intensity; , is a drift difference of amplitude; , is a drift difference of phase; is a serial number of noise type, corresponding to the noise type, is a serial number of noise intensity, corresponding to the noise intensity; is a current noise intensity.

[0028] The application provides an oscillation circuit loop analysis method based on physical characteristics of a crystal oscillator. The abstract "mapping relationship model" is embodied as a directly applicable mathematical formula, so that it is possible to adaptively adjust the performance parameter threshold value based on the noise evaluation result. Through the model, the judgment standard of the performance parameter can be dynamically adjusted according to the actual noise environment, so as to improve the accuracy and reliability of the oscillation circuit loop analysis of the crystal oscillator, especially in a complex noise environment such as a production line, the crystal oscillator meeting the production requirements can be more effectively screened out. The form of the linear model also ensures the simplicity and real-time performance of the calculation, which is beneficial to the application of the fast production line.

[0029] Further, the step S1 comprises:

[0030] S11: sensing an original sensing signal of the crystal oscillator and an original environmental interference signal in a non-contact manner through the first induction coil and the second induction coil respectively;

[0031] S12: performing signal amplification and signal filtering processing on the original sensing signal to obtain the processed crystal oscillator signal;

[0032] S13: Adjust the sampling frequency and sampling time of the original environmental interference signal according to the sampling frequency and sampling time of the original sensing signal, so that the adjusted original environmental interference signal is aligned in time domain with the processed crystal oscillator signal, to obtain the synchronized environmental interference signal.

[0033] Further, step S2 comprises:

[0034] S21: Construct a differential amplification circuit model, the differential amplification circuit comprising a first input end, a second input end and an output end, the first input end being used for inputting the crystal oscillator signal, and the second input end being used for inputting the environmental interference signal;

[0035] S22: Perform zero point calibration on the crystal oscillator signal and the environmental interference signal output after passing through the differential amplification circuit, to eliminate the direct current offset introduced by the non-ideal characteristics of the circuit elements, to obtain the differential signal.

[0036] Further, step S22 comprises:

[0037] S221: Obtain an initial direct current offset voltage value of the output end of the differential amplification circuit;

[0038] S222: Construct a zero point calibration circuit, the zero point calibration circuit comprising a digital-to-analog converter DAC and a summer, the output end of the digital-to-analog converter DAC being connected to the third input end of the summer, and the fourth input end of the summer being connected to the output end of the differential amplification circuit;

[0039] S223: According to the initial direct current offset voltage value, generate a calibration compensation voltage through the digital-to-analog converter DAC;

[0040] S224: Input the calibration compensation voltage to the third input end, and superimpose it with the crystal oscillator signal and the environmental interference signal output by the differential amplification circuit, to eliminate the initial direct current offset voltage value, to obtain the differential signal.

[0041] Further, step S3 comprises:

[0042] S31: Perform fast Fourier transform on the differential signal to obtain frequency spectrum data, determine the noise type and the noise intensity corresponding to the noise type according to the frequency distribution reflected by the frequency spectrum data;

[0043] S32: Perform noise suppression processing on the noise type, to remove periodic noise, random noise and impact noise in the noise type, to obtain the differential signal after noise suppression processing;

[0044] S33: performing spectrum analysis on the noise-suppressed differential signal to extract the frequency, amplitude and phase parameters of the crystal oscillator as actual performance parameters;

[0045] S34: taking the noise type and the noise intensity corresponding to the noise type as the noise evaluation result.

[0046] Further, step S5 comprises:

[0047] S51: obtaining an allowed error range window;

[0048] S52: comparing the actual performance parameters with the performance parameter threshold value, and determining whether the difference between the actual performance parameters and the performance parameter threshold value is within the allowed error range window, if yes, determining that the oscillation circuit of the crystal oscillator meets the production requirement; otherwise, determining that the oscillation circuit of the crystal oscillator does not meet the production requirement, and outputting the determination result.

[0049] Further, step S52 comprises:

[0050] S521: obtaining actual frequency, actual amplitude and actual phase according to the actual performance parameters, and obtaining frequency threshold value, amplitude threshold value and phase threshold value according to the performance parameter threshold value;

[0051] S522: determining whether the difference between the actual frequency and the frequency threshold value is within the allowed error range window, if yes, determining that the frequency of the crystal oscillator meets the production requirement; otherwise, determining that the oscillation circuit of the crystal oscillator does not meet the production requirement;

[0052] S523: determining whether the difference between the actual amplitude and the amplitude threshold value is within the allowed error range window, if yes, determining that the amplitude of the crystal oscillator meets the production requirement; otherwise, determining that the oscillation circuit of the crystal oscillator does not meet the production requirement;

[0053] S524: determining whether the difference between the actual phase and the phase threshold value is within the allowed error range window, if yes, determining that the phase of the crystal oscillator meets the production requirement; otherwise, determining that the oscillation circuit of the crystal oscillator does not meet the production requirement;

[0054] S525: if the frequency, amplitude and phase of the crystal oscillator all meet the production requirement, determining that the oscillation circuit of the crystal oscillator meets the production requirement, and displaying a qualified determination result through an indicator light; otherwise, determining that the oscillation circuit of the crystal oscillator does not meet the production requirement, and alarming an unqualified determination result through a buzzer.

[0055] Beneficial effects: the application proposes a kind of oscillation circuit analysis method based on the physical characteristics of crystal oscillator, by synchronously collecting crystal oscillator signal and environmental interference signal, signal basis is provided for subsequent difference operation.Using circuit difference operation, environmental interference of common mode is effectively suppressed, and the difference signal mainly containing crystal oscillator signal is obtained.Frequency spectrum analysis is carried out on the difference signal, the actual performance parameters of crystal oscillator are extracted, and noise is evaluated, to provide noise information for subsequent parameter threshold adjustment.According to the noise evaluation result, the calibration performance parameters of crystal oscillator are adaptively adjusted, and the performance parameter threshold more consistent with the current environmental noise level is obtained.The actual performance parameters are compared with the adjusted performance parameter threshold, to judge whether the oscillation circuit of crystal oscillator meets the production demand.Through the above steps, the present technical solution reduces environmental interference by difference operation, and adaptively adjusts performance parameter threshold by noise evaluation result, so as to realize accurate analysis of the oscillation circuit of crystal oscillator under environmental interference.Therefore, the present application has the beneficial effects of effectively improving the detection efficiency of high-precision electronic measuring instrument and the quality of products on the premise of production cost. BRIEF DESCRIPTION OF DRAWINGS

[0056] Figure 1 A flow chart of the oscillation circuit analysis method based on the physical characteristics of crystal oscillator proposed in the present application.

[0057] Figure 2 A structure diagram of the difference amplification circuit model proposed in the present application. DETAILED DESCRIPTION

[0058] The technical solutions in the embodiments of the present application will be described clearly and completely in the embodiments of the present application combined with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. The components of the embodiments of the present application described and indicated in the accompanying drawings can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0059] It should be noted that: similar reference numerals and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. Meanwhile, in the description of the present application, the terms "first", "second" and the like are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0060] At present, there is a lack of a non-destructive, fast oscillation circuit analysis method for high-precision electronic measuring instruments on the production line. In order to solve this problem, the present application proposes an oscillation circuit analysis method based on the physical characteristics of the crystal oscillator, as follows:

[0061] Please refer to Figure 1 , the first aspect, an oscillation circuit analysis method based on the physical characteristics of the crystal oscillator, the method comprising the steps of:

[0062] S1: obtaining the crystal oscillator signal and the environmental interference signal;

[0063] S2: performing circuit difference operation on the crystal oscillator signal and the environmental interference signal to obtain a difference signal;

[0064] S3: performing frequency spectrum analysis on the difference signal to extract the actual performance parameters of the crystal oscillator and obtain a noise evaluation result;

[0065] S4: obtaining the calibrated performance parameters of the crystal oscillator, and adaptively adjusting the calibrated performance parameters according to the noise evaluation result to obtain the adjusted performance parameter threshold;

[0066] S5: comparing the actual performance parameters with the performance parameter threshold to determine whether the oscillation circuit of the crystal oscillator meets the production requirements, and outputting the determination result.

[0067] In step S1, the crystal oscillator signal and the environmental interference signal can be acquired synchronously to eliminate environmental interference in subsequent difference operation. The signal acquisition method can be non-contact sensing, which uses an inductive coil close to the crystal oscillator and the environmental noise source to capture the signals respectively.

[0068] In step S2, the circuit difference operation is realized by using a difference amplification circuit, which receives the crystal oscillator signal and the environmental interference signal as input, subtracts the signals through the circuit structure, and suppresses the environmental interference as common-mode signal to output the difference signal.

[0069] In step S3, the frequency spectrum analysis is realized by using fast Fourier transform and other methods, the difference signal is converted to the frequency domain, and the actual performance parameters of the crystal oscillator such as frequency, amplitude and phase are analyzed. The noise evaluation result can include noise type and noise intensity, the noise type can be determined according to the frequency spectrum distribution characteristics, and the noise intensity can be reflected by the frequency spectrum amplitude.

[0070] In step S4, the calibration performance parameter is a crystal oscillator performance parameter measured in advance in a noise-free ideal environment. The adaptive adjustment process is performed according to the noise evaluation result obtained in step S3, and the calibration performance parameter is adjusted according to different noise types and intensities to obtain a performance parameter threshold value adapted to the current environment. The adjustment method can establish a mapping relationship model between the calibration performance parameter and the noise parameter, which can be a function or a lookup table.

[0071] In step S5, the actual performance parameter is compared with the adjusted performance parameter threshold value, and the comparison items can include frequency, amplitude, phase, etc. The comparison result is used to judge whether the crystal oscillator oscillation circuit loop meets the production requirements, and the judgment standard can be whether the difference between the actual performance parameter and the performance parameter threshold value is within the allowable error range. The judgment result is output in the form of a signal, such as a pass or fail indication. Through the above steps, accurate analysis of the crystal oscillator oscillation circuit loop under environmental interference can be achieved.

[0072] In some embodiments, for analyzing the performance of the crystal oscillator oscillation circuit loop in the analysis instrument on the electronic instrument production line, a non-contact induction coil is used to synchronously collect the crystal oscillator signal and the production line environmental interference signal. The induction coil is close to the crystal oscillator and the production line noise source to respectively sense the original signals. After signal amplification and filtering preprocessing, the original signals are input to the differential amplification circuit. The differential amplification circuit selects an operational amplifier with high common-mode rejection ratio to build, and inputs the preprocessed crystal oscillator signal and environmental interference signal to the same-phase input end and the anti-phase input end of the differential amplification circuit for differential operation to output a differential signal. After sampling by an analog-to-digital converter, the differential signal is subjected to frequency spectrum analysis by fast Fourier transform to obtain frequency spectrum data. The noise type and intensity are analyzed according to the frequency spectrum data, for example, the noise frequency is determined by the frequency spectrum peak position, and the noise intensity is determined by the peak amplitude. At the same time, the actual performance parameters of the crystal oscillator, such as frequency, amplitude, and phase, are extracted from the frequency spectrum data. The calibration frequency, calibration amplitude, and calibration phase of the crystal oscillator are measured in advance in a noise-free environment as calibration performance parameters. A mapping relationship between the calibration performance parameters and the noise intensity is established, for example, a linear mapping relationship, in which the frequency threshold value, the amplitude threshold value, and the phase threshold value are adjusted by a certain proportion when the noise intensity increases. According to the actual noise intensity, the adjusted frequency threshold value, amplitude threshold value, and phase threshold value are calculated by using the mapping relationship model. The actual frequency, actual amplitude, and actual phase are compared with the adjusted frequency threshold value, amplitude threshold value, and phase threshold value, respectively, to determine whether the difference is within a preset error range. If the frequency, amplitude, and phase are all within the error range, the crystal oscillator oscillation circuit loop is determined to be qualified, otherwise it is determined to be unqualified. The qualified result is displayed by a green indicator light, and the unqualified result is prompted by a red indicator light and a buzzer alarm.

[0073] Further, in step S4, the noise evaluation result includes noise types and noise intensities corresponding to different noise types; and step S4 includes:

[0074] S41: Obtain a calibration performance parameter of the crystal oscillator, and establish a mapping relationship model between the calibration performance parameter of the crystal oscillator and environmental noise;

[0075] S42: According to the mapping relationship model, calculate a performance parameter threshold of the crystal oscillator under the current noise type and noise intensity.

[0076] In step S41, the calibration performance parameter is obtained in the following manner: in an ideal experiment environment without noise, the frequency, amplitude and phase of the crystal oscillator are measured, and the measurement results are taken as the calibration performance parameter. The establishment process of the mapping relationship model of the environmental noise is as follows: first, collect historical environmental interference signals of the production line, and divide the historical environmental interference signals into multiple noise types and noise intensity levels corresponding to different noise types. For example, the noise types can include electromagnetic interference, mechanical vibration, etc., and the noise intensity levels can be divided into levels one, two and three. Then, in a controllable experiment environment, simulate various noise types and intensities on the production line, and measure the experimental performance parameters of the crystal oscillator under different noise conditions. The experimental performance parameters also include frequency, amplitude and phase. By comparing the experimental performance parameters with the calibration performance parameters, the drift difference of the frequency, amplitude and phase of the crystal oscillator under different noise types and intensities is calculated. The drift difference reflects the influence degree of noise on the performance parameters of the crystal oscillator. Based on these drift differences, the influence coefficients of different noise types and noise intensities on the calibration performance parameters can be determined. The influence coefficient can be understood as the quantitative influence degree of noise on the performance parameter. Finally, according to the influence coefficients, the mapping relationship model between the calibration performance parameter and the environmental noise is established. The mapping relationship model can be a mathematical formula, a lookup table or other forms of model, which is used to describe how the calibration performance parameter should be adjusted to obtain a reasonable performance parameter threshold under a given noise type and intensity.

[0077] In step S42, the calculation process of the performance parameter threshold is as follows: when the noise evaluation result in the actual production line environment determines the current noise type and noise intensity, according to the mapping relationship model established in step S41, the current noise type and noise intensity are taken as inputs, and the output result of the model is the performance parameter threshold under the current noise environment. The performance parameter threshold includes the frequency threshold, the amplitude threshold and the phase threshold. These thresholds are the adaptive adjustment results of the calibration performance parameter after considering the influence of environmental noise, and can more accurately reflect the performance requirements of the crystal oscillator in the actual noise environment.

[0078] Further, step S41 includes:

[0079] S411: Obtain the frequency, amplitude and phase of the crystal oscillator in a noise-free experimental environment as calibration performance parameters;

[0080] S412: Collect the historical environmental interference signals of the production line, and divide the historical environmental interference signals into multiple noise types and noise intensities corresponding to different noise types;

[0081] S413: Obtain the experimental performance parameters of the crystal oscillator under different noise types in the experimental environment;

[0082] S414: Calculate the drift difference of frequency, amplitude and phase between the experimental performance parameters and the calibration performance parameters respectively, determine the influence coefficient of different noise types and noise intensities on the calibration performance parameters according to the drift difference, and establish a mapping relationship model according to the influence coefficient.

[0083] In step S411, the calibration performance parameters can be obtained in a noise-free experimental environment such as a shielded room. The frequency, amplitude and phase parameters of the crystal oscillator are measured by a precision spectrum analyzer. These measured values are recorded as the baseline calibration performance parameters for subsequent performance evaluation comparison.

[0084] In step S412, the collection of historical environmental interference signals of the production line is realized by deploying various environmental signal collection devices such as electromagnetic field probes and vibration sensors on the production line. The collected signals are analyzed by a signal processing unit, for example, using fast Fourier transform method, etc., to identify the main noise types such as electromagnetic interference, mechanical vibration noise, power ripple noise, etc. For each type of noise, the noise intensity is quantified by statistical analysis method, for example, calculating the root mean square value, power spectral density and other parameters of the noise signal, and the noise intensity is divided into multiple levels, for example, level one, level two and level three.

[0085] In step S413, the experimental performance parameters are obtained in a controllable experimental environment. The experimental environment needs to be able to simulate various noise types and intensities on the production line. For example, electromagnetic interference is simulated by a signal generator, and mechanical vibration noise is simulated by a vibration table. Under each noise type and intensity, the frequency, amplitude and phase parameters of the crystal oscillator are measured again by the spectrum analyzer, and these measured values are recorded as the experimental performance parameters.

[0086] In step S414, the drift difference is calculated by comparing the experimental performance parameters obtained in step S413 with the calibration performance parameters obtained in step S411. For frequency, the drift difference is the frequency value in the experimental environment minus the frequency value in the noise-free environment. The amplitude drift difference and the phase drift difference are also calculated in a similar manner. The determination of the influence coefficients is based on the drift difference and the noise intensity. For example, the frequency influence coefficient can be obtained by dividing the frequency drift difference by the noise intensity, which represents the amount of frequency drift caused by unit noise intensity. Based on these influence coefficients, a quantitative relationship between the calibration performance parameters and the noise type and noise intensity is established.

[0087] Further, in step S414, the mapping relationship model is:

[0088] wherein, is the adjusted frequency threshold value, is the adjusted amplitude threshold value, is the adjusted phase threshold value, and the performance parameter threshold values include , , ;

[0089] wherein, , , represent the frequency, amplitude, and phase of the calibration performance parameters, respectively;

[0090] wherein, , , are the influence coefficients of the frequency, amplitude, and phase; , is the drift difference of the frequency, is the noise intensity; , is the drift difference of the amplitude; , is the drift difference of the phase; is the serial number of the noise type, corresponding to the noise type, is the serial number of the noise intensity, corresponding to the noise intensity; is the current noise intensity.

[0091] wherein the establishment and application process of the mapping relationship model are explained in detail. The model is for the three key performance parameters of frequency, amplitude, and phase, and uses a linear relationship for adjustment. The adjusted frequency threshold value is obtained by subtracting the product of the frequency influence coefficient, the frequency drift difference, and the current noise intensity from the calibration frequency threshold value. The adjustment of the amplitude threshold value and the phase threshold value is similar, both using a linear adjustment model.

[0092] Specifically, the establishment of the mapping relationship model first needs to obtain the drift difference of the crystal oscillator frequency, amplitude, and phase under different noise types and intensities through experiments in advance. The experimental process includes obtaining the calibrated performance parameters of the crystal oscillator in a noise-free environment, and collecting the experimental performance parameters of the crystal oscillator under different noise types and intensities. By comparing the experimental performance parameters with the calibrated performance parameters, the frequency drift difference, amplitude drift difference, and phase drift difference can be calculated. Then, based on these drift differences, the frequency influence coefficient, amplitude influence coefficient, and phase influence coefficient are calculated. These influence coefficients reflect the degree of influence of a specific noise type and intensity on the performance parameters. The calculation of the influence coefficients can be obtained by linear regression or other statistical analysis methods to analyze the relationship between the drift difference and the noise intensity.

[0093] In practical applications, when the noise type and intensity in the production line environment are detected, the mapping relationship model can be applied. By substituting the detected noise type and intensity into the mapping relationship model, and combining the pre-calculated influence coefficients and drift differences, the adjusted frequency threshold, amplitude threshold, and phase threshold can be quickly calculated. These adjusted thresholds will serve as the basis for determining whether the performance of the crystal oscillator meets the production requirements in the subsequent steps.

[0094] Further, step S1 includes:

[0095] S11: sensing the original sensing signal of the crystal oscillator and the original environmental interference signal in a non-contact manner through the first induction coil and the second induction coil, respectively;

[0096] S12: performing signal amplification and signal filtering processing on the original sensing signal to obtain the processed crystal oscillator signal;

[0097] S13: adjusting the sampling frequency and sampling time of the original environmental interference signal according to the sampling frequency and sampling time of the original sensing signal, so that the adjusted original environmental interference signal is aligned with the processed crystal oscillator signal in the time domain, to obtain the synchronized environmental interference signal.

[0098] In step S11, the first induction coil is placed close to the crystal oscillator to sense the electromagnetic signal generated by the crystal oscillator, and the second induction coil is placed away from the crystal oscillator but still in the same environmental interference to specifically sense the environmental interference signal. The induction coil can be an air-core coil or a magnetic-core coil, and the number of turns and size of the coil can be adjusted according to the actual strength of the sensing signal.

[0099] In step S12, the signal amplification can use a low-noise amplifier to increase the amplitude of the original sensing signal, so that the subsequent signal processing circuit can be effectively processed. The signal filtering can use a band-pass filter to filter out the noise outside the frequency band of the original sensing signal, such as high-frequency noise and low-frequency drift.

[0100] In step S13, the sampling frequency and sampling time of the original sensing signal are pre-set by the signal collection system, and the sampling frequency and sampling time of the environmental interference signal need to be adjusted according to the sampling parameters of the crystal oscillator signal. The adjustment method can be to adjust the clock frequency or sampling interval of the environmental interference signal collection system, so that the sampling points of the environmental interference signal are aligned with the sampling points of the crystal oscillator signal on the time axis.

[0101] Specifically, the first sensing coil and the second sensing coil are used to collect the original sensing signal and the environmental interference signal of the crystal oscillator in a non-contact manner, which avoids the influence of direct contact on the working state of the crystal oscillator and ensures the authenticity of signal collection. The original sensing signal is processed by signal amplification, and the signal strength is improved, which is beneficial to the effective processing of the subsequent circuit. Through signal filtering processing, the noise in the original sensing signal is filtered out, and the signal quality is improved. Further, by adjusting the sampling frequency and sampling time of the environmental interference signal, the synchronization alignment of the environmental interference signal and the crystal oscillator signal in the time domain is realized, which lays a foundation for effectively eliminating environmental interference in subsequent differential operation, and finally realizes the non-contact, high-quality and synchronous acquisition of the crystal oscillator signal and the environmental interference signal.

[0102] Further, step S2 includes:

[0103] S21: constructing a differential amplification circuit model, the differential amplification circuit including a first input end, a second input end and an output end, the first input end being used for inputting the crystal oscillator signal, and the second input end being used for inputting the environmental interference signal;

[0104] S22: performing zero-point calibration on the crystal oscillator signal and the environmental interference signal output after passing through the differential amplification circuit, eliminating the direct current offset introduced by the non-ideal characteristics of the circuit elements, and obtaining a differential signal.

[0105] Among them, the differential amplification circuit is constructed to suppress the common-mode interference characteristics of the differential amplification circuit and preliminarily reduce the influence of the environmental interference signal on the crystal oscillator signal. Specifically, the differential amplification circuit can be built using an operational amplifier, such as a low-noise operational amplifier with a model number of OPA2134. The first input end and the second input end can be connected to the first sensing coil and the second sensing coil respectively, and the first sensing coil and the second sensing coil are used to pick up the crystal oscillator signal and the environmental interference signal in a non-contact manner.

[0106] To realize zero point calibration, a zero point calibration circuit can be designed. The zero point calibration circuit can include a digital-to-analog converter (DAC), such as a model DAC8568, and an adder, which can be implemented using another operational amplifier, such as a precision operational amplifier with a model OPA2333. The output of the digital-to-analog converter (DAC) is connected to the third input of the adder, and the output of the differential amplification circuit is connected to the fourth input of the adder. By controlling the calibration compensation voltage output by the digital-to-analog converter (DAC), the DC offset at the output of the differential amplification circuit can be offset. The value of the calibration compensation voltage can be determined according to the initial DC offset voltage value, which can be measured by a high-precision voltmeter. The zero point calibration process can be iterated until the DC offset is sufficiently eliminated. Thus, subsequent frequency spectrum analysis of the differential signal can more accurately reflect the actual performance parameters of the crystal oscillator, improving the accuracy and reliability of the analysis results.

[0107] Further, step S22 includes:

[0108] S221: Obtain the initial DC offset voltage value at the output of the differential amplification circuit;

[0109] S222: Construct a zero point calibration circuit, which includes a digital-to-analog converter (DAC) and an adder, the output of the digital-to-analog converter (DAC) is connected to the third input of the adder, and the fourth input of the adder is connected to the output of the differential amplification circuit;

[0110] S223: According to the initial DC offset voltage value, generate a calibration compensation voltage through the digital-to-analog converter (DAC);

[0111] S224: Input the calibration compensation voltage to the third input, and superimpose it with the crystal oscillator signal and the environmental interference signal output by the differential amplification circuit to eliminate the initial DC offset voltage value, to obtain a differential signal.

[0112] Specifically, please refer to Figure 2 , the specific process of constructing the differential amplification circuit model is as follows:

[0113] The main function of the differential amplification circuit is to receive the crystal oscillator signal and the environmental interference signal, and output their differential signal, and the differential amplification structure is as follows:

[0114] It includes: a first input (Vin1) for receiving a crystal oscillator signal; a second input (Vin2) for receiving an environmental interference signal;

[0115] The output end (Vout) of the differential amplification circuit is used to output the differential signal;

[0116] The output of the differential amplifier circuit can be expressed as: Vout = Ad(Vin1 - Vin2), where Ad is the differential gain, representing the amplification factor of the circuit for differential signals.

[0117] A zero-point calibration circuit is provided, which mainly functions to eliminate the DC offset introduced by the non-ideal characteristics of the circuit components. The structure of the zero-point calibration circuit is as follows:

[0118] The adder is provided with three input terminals: the third input terminal (Vcomp) is used to receive the calibration compensation voltage generated by the digital-to-analog converter (DAC);

[0119] The fourth input terminal (Vdiff) is used to receive the output signal of the differential amplifier circuit.

[0120] The output terminal (Vout_final) of the zero-point calibration circuit is used to output the calibrated differential signal;

[0121] The output of the zero-point calibration circuit can be expressed as: Vout_final = Vdiff + Vcomp.

[0122] The digital-to-analog converter (DAC) is used to generate a calibration compensation voltage based on the initial DC offset voltage value. The specific steps are as follows:

[0123] Measure the initial DC offset voltage value Voffset at the output terminal of the differential amplifier circuit;

[0124] According to Voffset, generate a calibration compensation voltage Vcomp through DAC,

[0125] So that: Vcomp = -Voffset.

[0126] The function of the adder is to superimpose the calibration compensation voltage and the output signal of the differential amplifier circuit to eliminate the DC offset. The addition is expressed as: Vout_final = Vdiff + Vcomp.

[0127] In summary, the complete differential circuit model can be expressed as:

[0128] Differential amplifier circuit: Vdiff = Ad(Vin1 - Vin2);

[0129] 2. Zero-point calibration circuit: obtain the initial DC offset voltage value Voffset; generate a calibration compensation voltage Vcomp = -Voffset through DAC; adder output: Vout_final = Vdiff + Vcomp.

[0130] Further, step S3 includes:

[0131] S31: performing fast Fourier transform on the differential signal to obtain frequency spectrum data, determining the noise type according to the frequency distribution reflected by the frequency spectrum data, and the noise intensity corresponding to the noise type;

[0132] S32: performing noise suppression processing on the noise type to remove periodic noise, random noise and impact noise in the noise type, and obtaining the differential signal after noise suppression processing;

[0133] S33: performing frequency spectrum analysis on the differential signal after noise suppression processing, and extracting the frequency, amplitude and phase parameters of the crystal oscillator as actual performance parameters;

[0134] S34: taking the noise type and the noise intensity corresponding to the noise type as the noise evaluation result.

[0135] In step S31, fast Fourier transform is used to convert the differential signal in time domain to frequency domain, thereby obtaining frequency spectrum data. In the frequency spectrum data, different types of noise exhibit different frequency distribution characteristics in the frequency domain. For example, periodic noise usually exhibits discrete frequency peaks in the frequency spectrum, random noise exhibits broadband noise floor lifting in the frequency spectrum, and impact noise can cause transient broadband energy increase in the frequency spectrum. By analyzing the frequency distribution of the frequency spectrum data, the noise type can be identified, and the noise intensity can be evaluated according to the energy size of the noise component in the frequency spectrum data. For example, the strength of periodic noise can be represented by the amplitude of the frequency peak, the strength of random noise can be represented by the average energy level of the noise floor, and the strength of impact noise can be represented by the size of the transient energy peak.

[0136] In step S32, for the noise type determined in step S31, the corresponding noise suppression processing method is adopted. For periodic noise, a notch filter or an adaptive filter can be used for filtering. The notch filter is configured to have high attenuation at the frequency point of the periodic noise, thereby removing the periodic noise component. The adaptive filter can be adaptively adjusted according to the characteristics of the periodic noise to achieve more accurate noise filtering. For random noise, a Wiener filter or a Kalman filter can be used for suppression. The Wiener filter performs optimal filtering based on the statistical characteristics of the noise and the signal to minimize the noise component in the output signal. The Kalman filter can utilize the state space model of the signal and the noise to perform filtering, thereby effectively suppressing the random noise. For impact noise, a median filter or a wavelet threshold denoising method can be used for processing. The median filter can effectively suppress impulse-type impact noise while preserving the edge information of the signal. The wavelet threshold denoising method can separate the impact noise from the signal through wavelet transform and set a threshold to remove the noise component.

[0137] In step S33, the differential signal after noise suppression is subjected to spectrum analysis again, aiming to extract more accurate crystal oscillator performance parameters. Since the noise has been effectively suppressed, the spectrum analysis result will be less disturbed by noise, thus the frequency, amplitude and phase parameters of the crystal oscillator can be more accurately extracted as actual performance parameters, which will more truly reflect the performance of the crystal oscillator in the actual working environment.

[0138] In step S34, the noise type determined in step S31 and the evaluated noise intensity are output as noise evaluation results, which can be used for adaptive adjustment of the calibration performance parameters in subsequent step S4, providing quantitative information of the noise environment.

[0139] Further, step S5 includes:

[0140] S51: Obtain an allowed error range window;

[0141] S52: Compare the actual performance parameters with the performance parameter threshold, and determine whether the difference between the actual performance parameters and the performance parameter threshold is within the allowed error range window. If yes, it is determined that the oscillation circuit loop of the crystal oscillator meets the production requirements; otherwise, it is determined that the oscillation circuit loop of the crystal oscillator does not meet the production requirements, and the determination result is output.

[0142] Among them, obtaining an allowed error range window means determining an acceptable deviation range of a performance parameter, which can be realized in the following ways: a fixed error range value can be pre-set, for example, the allowed deviation of frequency is ±10ppm, the allowed deviation of amplitude is ±5%, and the allowed deviation of phase is ±2°; or the size of the error range window can be dynamically adjusted according to the specific model, application scenario or production requirement of the crystal oscillator, for example, a smaller error range window is set for a crystal oscillator with high precision requirement, and vice versa; or a reasonable error range window can be determined through experimental data or statistical analysis method, for example, the performance parameter data of a batch of qualified crystal oscillators are collected, the deviation distribution is analyzed, and the deviation range covering most of the qualified products is set as the allowed error range window.

[0143] The actual performance parameter is compared with the performance parameter threshold, and it is judged whether the difference between the actual performance parameter and the performance parameter threshold is within the allowable error range window, if yes, it is determined that the oscillation circuit loop of the crystal oscillator meets the production requirement; otherwise, it is determined that the oscillation circuit loop of the crystal oscillator does not meet the production requirement, and the judgment result is output. It refers to comparing the actually measured performance parameter of the crystal oscillator with the set performance parameter threshold, and considering the allowable error range. Specifically, first, the difference between the actual performance parameter and the performance parameter threshold is calculated, which can be an absolute value or a relative value. Then, it is judged whether the difference falls within the pre-set allowable error range window. If the difference is within the error range window, it is considered that the performance of the crystal oscillator meets the production requirement, and it is determined to be qualified. Conversely, if the difference exceeds the error range window, it is considered that the performance of the crystal oscillator does not meet the production requirement, and it is determined to be unqualified, and the judgment result is output, for example, the information of "qualified" or "unqualified" is displayed through the display screen, or the signal indicating lamp indicates the determination result.

[0144] Therefore, by introducing the allowable error range window, the judgment standard for the performance of the crystal oscillator is changed from absolute compliance to relative compliance, which is more in line with the actual production situation, avoids misjudgment caused by slight deviation, and improves the accuracy and practicality of the judgment. Step S51 provides the basis for the judgment of step S52, and step S52 performs specific comparison and judgment operation on the basis of step S51. The two work together to realize accurate evaluation of the performance of the crystal oscillator.

[0145] Further, step S52 includes:

[0146] S521: According to the actual performance parameter, the actual frequency, the actual amplitude and the actual phase are obtained; according to the performance parameter threshold, the frequency threshold, the amplitude threshold and the phase threshold are obtained;

[0147] S522: It is judged whether the difference between the actual frequency and the frequency threshold is within the allowable error range window, if yes, it is determined that the frequency of the crystal oscillator meets the production requirement; otherwise, it is determined that the oscillation circuit loop of the crystal oscillator does not meet the production requirement;

[0148] S523: It is judged whether the difference between the actual amplitude and the amplitude threshold is within the allowable error range window, if yes, it is determined that the amplitude of the crystal oscillator meets the production requirement; otherwise, it is determined that the oscillation circuit loop of the crystal oscillator does not meet the production requirement;

[0149] S524: It is judged whether the difference between the actual phase and the phase threshold is within the allowable error range window, if yes, it is determined that the phase of the crystal oscillator meets the production requirement; otherwise, it is determined that the oscillation circuit loop of the crystal oscillator does not meet the production requirement;

[0150] S525: If the frequency, amplitude and phase of the crystal oscillator meet the production requirements, it is determined that the oscillation circuit of the crystal oscillator meets the production requirements, and the pass result is displayed through the indicator light; otherwise, it is determined that the oscillation circuit of the crystal oscillator does not meet the production requirements, and the unqualified determination result is prompted through the buzzer alarm.

[0151] In the scheme, the performance judgment process of the oscillation circuit of the crystal oscillator is refined. The actual performance parameters and the performance parameter threshold values are decomposed into three parameter pairs of actual frequency and frequency threshold value, actual amplitude and amplitude threshold value, and actual phase and phase threshold value. For each parameter pair, it is judged whether the difference is within the allowable error range window, so as to determine whether the frequency, amplitude and phase meet the production requirements respectively. Only when the frequency, amplitude and phase all meet the production requirements, the oscillation circuit of the crystal oscillator can be finally determined to be qualified. The indicator light is used to display the qualified result, and the buzzer is used to alarm the unqualified result, so that the determination result is more intuitive.

[0152] In this document, the terms such as first and second are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations.

[0153] The above only describes the embodiments of the present application and is not used to limit the protection scope of the present application. For those skilled in the art, the present application can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for analyzing oscillation circuit loops based on the physical characteristics of crystal oscillators, characterized in that, The method comprises the steps of: S1: The original inductive signal of the crystal oscillator and the original environmental interference signal are inductively sensed by a first inductive coil and a second inductive coil respectively in a non-contact manner, the original inductive signal is subjected to signal amplification and signal filtering processing to obtain a processed crystal oscillator signal, and the sampling frequency and sampling time of the original environmental interference signal are adjusted according to the sampling frequency and sampling time of the original inductive signal, so that the original environmental interference signal after adjustment is aligned with the processed crystal oscillator signal in the time domain to obtain a synchronized environmental interference signal; S2: Circuit difference operation is performed on the crystal oscillator signal and the environmental interference signal, and zero point calibration is performed to eliminate the direct current offset introduced by the non-ideal characteristics of circuit elements to obtain a difference signal; S3: The difference signal is subjected to frequency spectrum analysis to extract the actual performance parameters of the crystal oscillator and obtain a noise evaluation result; the noise evaluation result comprises noise types and noise intensities corresponding to different noise types; S4: The calibration performance parameters of the crystal oscillator are obtained, and a mapping relationship model of the calibration performance parameters of the crystal oscillator and environmental noise is established; according to the mapping relationship model, the performance parameter threshold of the crystal oscillator under the current noise type and noise intensity is calculated; S5: The actual performance parameters are compared with the performance parameter threshold to determine whether the oscillation circuit of the crystal oscillator meets the production requirements, and a judgment result is output.

2. The method of claim 1, wherein the method is based on physical properties of a crystal oscillator. Step S4 comprises: S411: The frequency, amplitude and phase of the crystal oscillator in a noise-free experimental environment are obtained as the calibration performance parameters; S412: The historical environmental interference signals of the production line are collected, and the historical environmental interference signals are divided into a plurality of noise types and noise intensities corresponding to different noise types; S413: Experimental performance parameters of the crystal oscillator under different noise types in an experimental environment are obtained; S414: The frequency, amplitude and phase drift difference values between the experimental performance parameters and the calibration performance parameters are calculated respectively, the influence coefficients of different noise types and noise intensities on the calibration performance parameters are determined according to the drift difference values, and the mapping relationship model is established according to the influence coefficients.

3. The method for analyzing oscillation circuit loops based on the physical characteristics of a crystal oscillator according to claim 2, characterized in that, In step S414, the mapping relationship model is: wherein, is an adjusted frequency threshold value, is an adjusted amplitude threshold value, is an adjusted phase threshold value, and the performance parameter threshold value includes , , ; wherein , , respectively represent the frequency, amplitude and phase of the calibration performance parameter; Wherein, , , is the frequency influence coefficient, the amplitude influence coefficient, the phase influence coefficient; , is the frequency drift difference, is the noise intensity; , is the amplitude drift difference; , is the phase drift difference; i is the serial number of the noise type, corresponding to the noise type, and j is the serial number of the noise intensity, corresponding to the noise intensity; is the current noise intensity.

4. The method of claim 1, wherein the method is a method of analyzing a ring oscillator circuit based on physical characteristics of a crystal oscillator. Step S2 comprises: S21: A differential amplification circuit model is constructed, the differential amplification circuit comprises a first input end, a second input end and an output end, the first input end is used for inputting the crystal oscillator signal, and the second input end is used for inputting the environmental interference signal; S22: The crystal oscillator signal and the environmental interference signal output after passing through the differential amplification circuit are subjected to zero point calibration to eliminate the direct current offset introduced by the non-ideal characteristics of circuit elements to obtain the difference signal.

5. The method of claim 4, wherein the method is based on physical properties of the crystal oscillator. Step S22 comprises: ​ S221: An initial direct current offset voltage value of the output end of the differential amplification circuit is obtained; S222: Construct a zero point calibration circuit, the zero point calibration circuit comprising a digital-to-analog converter DAC and an adder, an output terminal of the digital-to-analog converter DAC being connected to a third input terminal of the adder, and a fourth input terminal of the adder being connected to an output terminal of the differential amplification circuit; S223: According to the initial DC offset voltage value, a calibration compensation voltage is generated by the digital-to-analog converter DAC; S224: The calibration compensation voltage is input to the third input terminal, and the crystal oscillator signal and the environmental interference signal output by the differential amplification circuit are superimposed to eliminate the initial DC offset voltage value, so as to obtain the differential signal.

6. The method of claim 1, wherein the method is based on physical properties of a crystal oscillator. Step S3 comprises: S31: Fast Fourier transform is performed on the differential signal to obtain frequency spectrum data, and a noise type and a noise intensity corresponding to the noise type are determined according to a frequency distribution reflected by the frequency spectrum data; S32: The noise type is subjected to noise suppression processing to remove periodic noise, random noise and impact noise in the noise type, so as to obtain a differential signal subjected to noise suppression processing; S33: Frequency spectrum analysis is performed on the differential signal subjected to noise suppression processing to extract a frequency, an amplitude and a phase parameter of the crystal oscillator as actual performance parameters; S34: The noise type and the noise intensity corresponding to the noise type are taken as the noise evaluation result.

7. The method of claim 1, wherein the method is a method of analyzing a ring circuit of an oscillation circuit based on a physical characteristic of a crystal oscillator. Step S5 comprises: S51: An allowed error range window is obtained; S52: The actual performance parameters and the performance parameter threshold value are compared, and it is determined whether a difference between the actual performance parameters and the performance parameter threshold value is within the allowed error range window, if yes, it is determined that the oscillation circuit loop of the crystal oscillator meets the production requirement; otherwise, it is determined that the oscillation circuit loop of the crystal oscillator does not meet the production requirement, and a judgment result is output.

8. The method of claim 7, wherein the method is based on physical properties of a crystal oscillator. Step S52 comprises: ​ S521: Actual frequency, actual amplitude and actual phase are obtained according to the actual performance parameters, and frequency threshold value, amplitude threshold value and phase threshold value are obtained according to the performance parameter threshold value; S522: It is determined whether a difference between the actual frequency and the frequency threshold value is within the allowed error range window, if yes, it is determined that the frequency of the crystal oscillator meets the production requirement; otherwise, it is determined that the oscillation circuit loop of the crystal oscillator does not meet the production requirement; S523: It is determined whether a difference between the actual amplitude and the amplitude threshold value is within the allowed error range window, if yes, it is determined that the amplitude of the crystal oscillator meets the production requirement; otherwise, it is determined that the oscillation circuit loop of the crystal oscillator does not meet the production requirement; S524: It is determined whether a difference between the actual phase and the phase threshold value is within the allowed error range window, if yes, it is determined that the phase of the crystal oscillator meets the production requirement; otherwise, it is determined that the oscillation circuit loop of the crystal oscillator does not meet the production requirement; S525: If the frequency, amplitude and phase of the crystal oscillator meet the production requirements, it is determined that the oscillation circuit loop of the crystal oscillator meets the production requirements, and the pass judgment result is displayed through the indicator light; otherwise, it is determined that the oscillation circuit loop of the crystal oscillator does not meet the production requirements, and the unqualified judgment result is prompted through the buzzer alarm.

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