A method and system for measuring the length of a radio frequency transmission line

Abstract

The present application relates to the field of radio frequency transmission line measurement technology, and specifically to a method and system for measuring the length of a radio frequency transmission line, the method comprising: obtaining a transmission signal and a reflection signal of a radio frequency transmission line to be measured, screening out each reflection pulse signal, determining the degree of distortion based on the goodness of fit of a curve fitting of each reflection pulse sequence, analyzing the number of maximum values ​​on each curve after fitting and the fluctuation deviation of each maximum value, determining the pulse jump coefficient, and then obtaining the reflection stability of each reflection pulse signal, combining the correlation between each reflection pulse and the transmission signal, as well as the fundamental frequency difference and fundamental frequency energy intensity difference between each reflection pulse signal and the transmission signal, obtaining the reflection determination coefficient of each reflection pulse signal, screening out the real tail end reflection pulse signal, and calculating the transmission length of the radio frequency transmission line to be measured. The present application improves the length detection accuracy of the radio frequency transmission line.

Description

Technical Field

[0001] The present application relates to the technical field of radio frequency transmission line measurement, and in particular to a method and system for measuring the length of a radio frequency transmission line. Background Art

[0002] An RF transmission line is a conductor structure used to transmit radio frequency (RF) signals. Its purpose is to transmit RF signals from the input end to the output end while reducing signal attenuation and interference. The length of the RF transmission line is critical to traditional signal systems. The length of the RF transmission line will affect the impedance matching, phase relationship, and accuracy of the transmission model. Usually, the RF transmission line is long, wrapped around a wooden barrel, or buried deep underground. At this time, it is difficult to accurately measure the length of the RF transmission line using conventional appearance-based methods.

[0003] Therefore, a method utilizing the transmission characteristics of radio frequency signals is needed to measure the precise length of the radio frequency transmission line. The time domain reflectometry method TDR (Time Domain Reflectometer) can be used to measure the length of the radio frequency transmission line. The principle mainly based on this is that when the signal is transmitted in the transmission path, when the impedance of the transmission path changes, a part of the signal will be reflected, and the length of the transmission line is determined by the time difference between the transmitted signal and the reflected signal. Ideally, the line impedance of the radio frequency transmission line is consistent. When the signal is transmitted to the end, the line is in an open circuit state. At this time, the signal is reflected to the transmitting end, and the length of the transmission line is measured. However, in actual practice, if the radio frequency transmission line is bent or part of the line is damaged, the radio frequency transmission line will have impedance changes, resulting in multiple reflections. As a result, the reflected signal measured at the input end cannot be accurately judged, resulting in errors in the measured length. Summary of the invention

[0004] In order to solve the above technical problems, the purpose of this application is to provide a method and system for measuring the length of a radio frequency transmission line. The technical solutions adopted are as follows:

[0005] The present application provides a method for measuring the length of a radio frequency transmission line, comprising the following steps:

[0006] Obtain the transmission signal of the time domain reflectometer and the reflection signal of the RF transmission line to be tested;

[0007] Performing baseline correction on the reflected signal and screening to obtain each reflected pulse signal, the signal intensity of each reflected pulse signal constitutes each reflected pulse sequence;

[0008] According to the goodness of fit of the curve fitting of each reflected pulse sequence, combined with the similarity of the signal strength between the starting point and the first inflection point of the reflected pulse sequence and the signal strength between the last inflection point and the end point, the distortion of each reflected pulse signal is determined; the number of maximum values ​​on each curve after fitting and the fluctuation deviation of each maximum value are analyzed to determine the pulse jump coefficient of each reflected pulse signal;

[0009] Obtaining the reflection stability of each reflected pulse signal based on the distortion and pulse jump coefficient of each reflected pulse signal;

[0010] Based on the correlation between each reflected pulse sequence and the transmitted signal, as well as the fundamental frequency difference and fundamental frequency energy intensity difference between each reflected pulse signal and the transmitted signal, combined with the reflection stability of each reflected pulse signal, the reflection determination coefficient of each reflected pulse signal is obtained;

[0011] The real tail end reflection pulse signal is screened based on the numerical value of the reflection determination coefficient, and the transmission length of the RF transmission line to be tested is obtained according to the time interval between the transmitted signal and the real tail end reflection pulse signal, combined with the speed of light in vacuum and the preset speed factor of the RF transmission line to be tested.

[0012] Preferably, each reflected pulse signal further includes:

[0013] All signal intensities of the reflected signals are combined into a signal intensity sequence, and the signal intensity sequence is baseline corrected to obtain the signal intensity corresponding to the baseline , if the strengths of a preset number of signals are all greater than the screening threshold, the partial signal corresponding to the preset number of signal strengths is taken as a reflected pulse signal, where the screening threshold is .

[0014] Preferably, the distortion of each reflected pulse signal is expressed as:

[0015] ; Wherein, B represents the distortion of the current reflected pulse signal, Indicates the goodness of fit of the current reflected pulse sequence curve, cos() indicates the cosine value, , They respectively represent the sequence composed of all signal intensities between the starting point and the first inflection point of the current reflected pulse sequence, and the sequence composed of all signal intensities between the last inflection point and the end point.

[0016] Preferably, the pulse jump coefficient of each reflected pulse signal is the product of the number of maximum values ​​on each curve after fitting each reflected pulse sequence and the variance of all maximum values.

[0017] Preferably, the expression of the reflection stability of each reflected pulse signal is: ; Where A, B, and C represent the reflection stability, distortion, and pulse jump coefficient of the current reflected pulse signal respectively; when , set the reflection stability to a value greater than 10.

[0018] Preferably, the expression of the reflection determination coefficient of each reflected pulse signal is:

[0019] ; In the formula, D and A represent the reflection determination coefficient and reflection stability of the current reflected pulse signal respectively, and They represent the transmitted pulse sequence and the reflected pulse sequence corresponding to the current reflected pulse signal, respectively. The transmitted pulse sequence is composed of all signal intensities of the transmitted signal. represents the Pearson correlation coefficient, and Indicates the fundamental frequency energy deviation and fundamental frequency deviation between the current reflected pulse signal and the transmitted signal.

[0020] Preferably, the fundamental frequency energy deviation is the difference between the fundamental frequency corresponding energy intensities of the current reflected pulse signal and the transmitted signal in the frequency domain, and the fundamental frequency deviation is the difference between the fundamental frequencies of the current reflected pulse signal and the transmitted signal in the frequency domain.

[0021] Preferably, the real tail end reflected pulse signal is a reflected pulse signal corresponding to the maximum value of the reflection determination coefficient.

[0022] Preferably, the expression of the transmission length of the radio frequency transmission line to be tested is: ; Where L represents the length of the RF transmission line to be tested, is the speed of light in vacuum, represents the velocity factor of the RF transmission line to be tested, Indicates the time interval between the transmitted signal and the actual tail end reflected pulse signal.

[0023] An embodiment of the present application also provides a radio frequency transmission line length measurement system, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, wherein the processor implements the steps of any one of the above methods when executing the computer program.

[0024] From the above, it can be seen that the method and system for measuring the length of a radio frequency transmission line provided by the present application have at least the following beneficial effects:

[0025] This application obtains the reflected pulse signal of the RF transmission line to be detected through a time domain reflectometer, and constructs the reflection stability based on the fluctuation non-smooth characteristics and jump edge characteristics of the reflected pulse sequence data in a single reflected pulse signal, reflecting the interference of each reflected pulse signal by the abnormal point of impedance change and the distortion of the signal, and uses the frequency domain difference information between the reflected pulse signal and the transmitted pulse signal to obtain the reflection determination coefficient, thereby determining the real tail end reflected pulse signal, and finally determining the time difference to obtain the real length of the RF transmission line. Compared with the traditional time domain reflection method, this application focuses on analyzing the impedance discontinuity caused by multiple bends and damages on the RF transmission line, and analyzing the defects of the multiple reflection phenomenon that occurs in this case causing interference to the measurement of the length of the RF transmission line, aiming to analyze the morphological interference difference between the abnormal reflected pulse signal and the normal reflected pulse signal, so as to determine the real tail end reflected pulse signal and improve the detection accuracy of the length of the RF transmission line. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present application or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0027] Figure 1 A flowchart of a method for measuring the length of a radio frequency transmission line provided in this application;

[0028] Figure 2 Schematic diagram of the measurement principle of the time domain reflectometer provided in this application. DETAILED DESCRIPTION

[0029] In order to further explain the technical means and effects adopted by the present application to achieve the predetermined invention purpose, the following is a detailed description of the specific implementation, structure, features and effects of a radio frequency transmission line length measurement method and system proposed in the present application in combination with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "another embodiment" does not necessarily refer to the same embodiment. In addition, specific features, structures or characteristics in one or more embodiments may be combined in any suitable form.

[0030] Unless otherwise specified and limited, terms such as "comprises", "comprising" or any other variants thereof are intended to cover non-exclusive inclusion, so that a circuit structure, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such articles or devices. In the absence of further restrictions, an element defined by the sentence "comprising a ..." does not exclude the presence of other identical elements in the article or device including the element. In addition, the term "and\or" used herein includes any and all combinations of one or more related listed items. All technical and scientific terms used herein have the same meaning as those commonly understood by technicians in the technical field of this application.

[0031] The following is a detailed description of a method and system for measuring the length of a radio frequency transmission line provided by the present application in conjunction with the accompanying drawings.

[0032] See also Figure 1 , which shows a flowchart of a method for measuring the length of a radio frequency transmission line provided by an embodiment of the present application, comprising the following steps:

[0033] Step 1: Obtain the transmission signal of the time domain reflectometer and the reflection signal of the RF transmission line to be tested.

[0034] The measurement principle diagram of the time domain reflectometer is as follows: Figure 2 As shown, it mainly includes a signal generator, a power divider and an oscilloscope. The signal generator is used to generate a pulse signal source, the power divider is used to achieve an even distribution of the signal power of the signal source, and the oscilloscope is used to measure the transmitted signal and the reflected signal, thereby determining the transmission delay.

[0035] Connect the RF transmission line to be tested through the probe of the time domain reflectometer. The time domain reflectometer transmits a rectangular pulse signal with a frequency of 100MHZ and a duration of 2μs. When the transmission is completed, it will stop transmitting. Figure 2 The oscilloscope collects the pulse signal of the detection port at a sampling frequency of 1 GHZ from the beginning of transmission, and sets the sampling period to 10s, thereby obtaining the reflected signal of the RF transmission line to be tested. For the convenience of description, in this embodiment, all signal strengths of the reflected signal are combined into a signal strength sequence. It should be noted that in the process of signal transmission and reflection, the signal strength in this embodiment is characterized by a voltage value, and other parts of this embodiment will not be described one by one.

[0036] Step 2: Perform baseline correction on the reflected signal and screen to obtain each reflected pulse signal, and the signal intensity of each reflected pulse signal constitutes each reflected pulse sequence.

[0037] The pulse signal emitted by the signal generator is evenly distributed to the oscilloscope and the RF transmission line to be detected through the power divider. Ideally, the RF transmission line is continuous, uninterrupted and undamaged. At this time, the impedance per unit length of the RF transmission line is fixed and can be regarded as continuous impedance. When the pulse signal is transmitted from the detection end to the tail end of the RF transmission line, since the other end is in an open circuit state, it can be considered that the impedance is infinite. At this time, the pulse signal is fully reflected back to the end to be detected, and the length of the transmission line can be determined by measuring the time difference of the round trip.

[0038] However, in actual practice, since the RF transmission line is buried deep underground, the line may be bent or slightly damaged during deployment, which will affect the line impedance at the abnormal location. At this time, when the pulse signal is transmitted to the abnormal location, due to the change in impedance reflection, a small part of the signal will be reflected in advance, resulting in multiple reflection problems at the detection end. At the same time, since the intensity of the reflected pulse signal is specific, after multiple rounds of early reflection and transmission loss, the energy intensity of the reflected signal at the tail end of the transmission line is relatively small, which may be considered as microwave interference during the identification process. Therefore, the reflected pulse signal reflected in advance is mistakenly judged as the tail end reflection signal, resulting in deviation in time judgment and affecting the measurement of the transmission line length.

[0039] Through observation, it is found that for the impedance change caused by bending or slight damage to the line, since the transmission structure of the RF transmission line is changed and even exposed to the external cluttered environment, the reflected pulse signal will have more noise points, making the overall smoothness of the reflected pulse signal poor, and more jump edges are likely to appear on the high level of the rectangular pulse signal. The reason for these jump edges is the impedance mismatch at the abnormal point, which causes overshoot and ringing.

[0040] Furthermore, in order to divide the reflected pulse signal collected by the oscilloscope, the collected reflected signal is subjected to baseline correction of the signal intensity sequence through a baseline correction algorithm, and the voltage corresponding to the baseline is obtained as ,Will As the screening threshold, the points in the signal strength sequence that are greater than the screening threshold are marked. If there are Q consecutive signal strengths that are all greater than the screening threshold, the partial signal corresponding to the consecutive Q signal strengths in the reflected signal is regarded as a reflected pulse signal. For ease of understanding and description, in this embodiment, all signal strengths corresponding to the reflected pulse signal are combined into a reflected pulse sequence. It should be noted that in this embodiment, Q=100.

[0041] Step 3: Determine the distortion of each reflected pulse signal based on the goodness of fit of the curve fitting of each reflected pulse sequence and the similarity between the signal strength between the starting point and the first inflection point of the reflected pulse sequence and the signal strength between the last inflection point and the end point.

[0042] In this embodiment, the distortion of each reflected pulse signal is analyzed according to the distribution of signal strength in each reflected pulse sequence. In this embodiment, taking the current reflected pulse signal as an example, curve fitting is performed on the reflected pulse sequence corresponding to the current reflected pulse signal to obtain the current reflected pulse curve, and the inflection point in the reflected pulse curve is obtained using an inflection point detection algorithm.

[0043] Furthermore, according to the goodness of fit of the curve fitting of each reflected pulse sequence, the distortion B of each reflected pulse signal is constructed by combining the similarity of the signal strength between the starting point and the first inflection point of the reflected pulse sequence and the signal strength between the last inflection point and the end point:

[0044] ; Wherein, B represents the distortion of the current reflected pulse signal, Indicates the goodness of fit of the current reflected pulse sequence curve, cos() indicates the cosine value, Represents the sequence of all signal intensities between the starting point and the first inflection point of the reflected pulse sequence. Represents a sequence consisting of all signal intensities between the last inflection point and the end point of the reflected pulse sequence.

[0045] Ideally, the reflected pulse signal is close to the rectangular pulse signal. Therefore, in an ideal situation, the first inflection point and the last inflection point correspond to the rising edge end point and the falling edge starting point of the rectangular pulse signal respectively, and the first vector and the second vector are parallel. However, if the reflected pulse signal is a reflection signal of an abnormal point, the signal is easily distorted by external interference. At this time, the rising edge and the falling edge will no longer be parallel but have a certain angle. The more serious the distortion, the larger the corresponding angle. At the same time, due to the distortion of the reflected pulse signal, more noise points will appear in the corresponding reflected pulse sequence. At this time, the goodness of fit of the obtained signal is smaller, and the distortion of the reflected pulse signal is finally larger.

[0046] Step 4: Analyze the number of maximum values ​​on each curve after fitting and the fluctuation deviation of each maximum value to determine the pulse jump coefficient of each reflected pulse signal.

[0047] For the reflected pulse curve obtained by fitting the reflected pulse sequence of the current reflected pulse signal, the number of maxima on the reflected pulse curve and the degree of deviation between the maxima are analyzed, the pulse jump degree of the reflected pulse signal is analyzed, and the pulse jump coefficient is constructed. Preferably, the product of the number of maxima on the reflected pulse curve corresponding to the current reflected pulse signal and the variance of all maxima on the reflected pulse curve is taken as the pulse jump coefficient of the current reflected pulse signal. For ease of understanding, the calculation formula in this embodiment is: ; Where C represents the pulse jump coefficient of the current reflected pulse signal, Represents the number of maxima on the reflected pulse curve, Represents the variance of all maxima on the reflected pulse curve.

[0048] If the current reflected pulse signal is a reflected signal of an abnormal point, the signal is disturbed by the external environment at this time, which will cause more jump edges in the high level of the rectangular pulse signal, that is, the voltage signal measured at the high level fluctuates, and the greater the degree of fluctuation, the more maximum points are obtained at this time, and the greater the deviation between the maximum point of the signal strength in the reflected pulse signal and the average value of all maximum points, the greater the pulse jump weight of the reflected pulse signal is.

[0049] Step 5: Based on the distortion and pulse jump coefficient of each reflected pulse signal, the reflection stability of each reflected pulse signal is obtained.

[0050] According to the above process of this embodiment, the distortion degree reflecting the degree of distortion of the reflected pulse signal and the pulse jump coefficient reflecting the degree of fluctuation of the level jump of the reflected pulse signal can be obtained. Based on this, the stability of each reflected pulse signal is analyzed. In this embodiment, based on the distortion degree and the pulse jump coefficient of each reflected pulse signal, the reflection stability A of each reflected pulse signal is obtained, which is specifically: ; Where A represents the reflection stability of the current reflected pulse signal. It should be noted that when When the shape of the reflected pulse signal is close to the rectangular pulse signal during transmission, that is, the reflected pulse signal is highly similar to the transmitted signal, and the corresponding reflected pulse signal has a high stability, and the reflected pulse signal has a greater reflection stability. Therefore, when When the reflected pulse signal is set to a value greater than 10, it is set to 20 in this embodiment.

[0051] For abnormal reflected pulse signals, due to the influence of the transmission line effect of the RF transmission line and the interference of external noise, the reflected pulse signals at the abnormal points will be distorted with rectangles, and there will be more noise points in the signal, so the corresponding distortion value will be larger. At the same time, the abnormal reflected pulse signals will have more jump edges, and the jump distortion coefficient will be larger, and the reflection stability of the abnormal reflected pulse signals will be smaller. On the contrary, for normal reflected pulse signals, their shape is close to the rectangular pulse signal during transmission, so the smaller the distortion and pulse jump coefficient are, almost close to zero, the greater the reflection stability should be.

[0052] It can be understood that the reflection stability of each reflected pulse signal is used to distinguish abnormal reflection signals from normal reflected pulse signals at the tail end of the RF transmission line. The greater the reflection stability, the more likely it is that it is a normal tail end reflected pulse signal. Otherwise, the reflected pulse signal has a large fluctuation degree and severe signal jitter. Therefore, the smaller the reflection stability of the reflected pulse signal, the more likely it is that it is an abnormal reflected pulse signal.

[0053] Step 6: Based on the correlation between each reflected pulse sequence and the transmitted signal, as well as the fundamental frequency difference and fundamental frequency energy intensity difference between each reflected pulse signal and the transmitted signal, combined with the reflection stability of each reflected pulse signal, the reflection determination coefficient of each reflected pulse signal is obtained.

[0054] In the actual process, the pulse signal reaching the tail end will be totally reflected, that is, reflected back to the detection end along the negative transmission direction. It should be noted that in this embodiment, the direction from the detection end to the tail end is marked as the positive transmission direction, and the direction from the tail end to the detection end is marked as the negative transmission direction. However, when the pulse signal totally reflected from the tail end is transmitted along the negative transmission direction, part of the signal will still be reflected when it reaches the abnormal point, and the re-reflected signal will continue to be transmitted along the positive transmission direction. Therefore, the reflected pulse signal received by the detection end during the entire sampling period will have multiple pulse signals reflected back from the tail end, and even mixed with reflected pulse signals simulated by random noise. Therefore, the reflected pulse signal is further analyzed in this embodiment.

[0055] All the above-mentioned reflected pulse signals include the pulse signal normally reflected back from the tail end, the pulse signal returned to the detection end after multiple reflections from the abnormal point, and the tail end reflection signal simulated by random noise.

[0056] For the normal tail end reflection signal, since it does not go through multiple rounds of reflection, the transmission line of the normal reflection signal is the shortest, so the attenuation of the signal strength is the smallest compared with other reflected pulse signals. At the same time, since the tail end fully reflects the pulse signal, the fundamental frequency and shape of the normal reflection pulse signal are closest to the rectangular pulse signal during transmission.

[0057] Based on the above analysis, according to the correlation between each reflected pulse sequence and the transmitted signal, and analyzing the fundamental frequency difference and fundamental frequency energy intensity difference between each reflected pulse signal and the transmitted signal, combined with the reflection stability of each reflected pulse signal, the reflection determination coefficient of each reflected pulse signal is obtained. In this embodiment, the calculation formula is:

[0058] ; Where D represents the reflection determination coefficient of the current reflected pulse signal, and They represent the transmitted pulse sequence and the reflected pulse sequence corresponding to the current reflected pulse signal. The transmitted pulse sequence is composed of all signal intensities of the transmitted signal. It represents the Pearson correlation coefficient. It should be noted that if the two sequences are of unequal length, the sequences are filled to equal length by linear interpolation method. and Indicates the fundamental frequency energy deviation and fundamental frequency deviation between the current reflected pulse signal and the transmitted signal.

[0059] Among them, the specific method of obtaining the fundamental frequency energy deviation and the fundamental frequency deviation is that the fundamental frequency energy deviation is the difference between the fundamental frequency corresponding energy intensity of the current reflected pulse signal and the transmitted signal in the frequency domain, and the fundamental frequency deviation is the difference between the fundamental frequency of the current reflected pulse signal and the transmitted signal in the frequency domain.

[0060] Preferably, in this embodiment, fast Fourier transform is performed on the current reflected pulse signal and the transmitted signal respectively, and the absolute value of the energy intensity difference between the fundamental frequencies of the current reflected pulse signal and the transmitted signal is taken as the fundamental frequency energy deviation between the current reflected pulse signal and the transmitted signal, and the absolute value of the fundamental frequency difference between the current reflected pulse signal and the transmitted signal is taken as the fundamental frequency deviation between the current reflected pulse signal and the transmitted signal.

[0061] For the interference reflected pulse signal that has been screened out by multiple rounds of reflection and random noise, the interference reflected pulse signal has a poor sequence similarity with the transmitted rectangular pulse signal due to the extension of the transmission length of the pulse signal after multiple rounds of reflection or the influence of the randomness of the noise, and the energy difference corresponding to the fundamental frequency in the frequency domain is large, and the fundamental frequency difference is large, so the corresponding reflection determination coefficient is small. On the contrary, if the normal reflected signal has the shortest transmission line, the signal attenuation is small, and the interference is small, so it is closest to the transmitted signal, and the reflection determination coefficient is also larger.

[0062] Step 7: Filter the real tail end reflection pulse signal based on the numerical value of the reflection determination coefficient, and obtain the transmission length of the RF transmission line to be tested according to the time interval between the transmitted signal and the real tail end reflection pulse signal, combined with the speed of light in vacuum and the preset speed factor of the RF transmission line to be tested.

[0063] The reflection determination coefficient of each reflected pulse signal is obtained through step 6, which is calculated based on the similarity between the reflected pulse sequence and the transmitted pulse and the frequency domain difference. The reflection determination coefficients of all reflected pulse signals are arranged in descending order, and the reflected pulse signal with the largest reflection determination coefficient is recorded as the true tail end reflected pulse signal.

[0064] By counting the time interval between the transmission signal and the real tail end reflected pulse signal, in this embodiment, the time interval between the starting points of the two is denoted by express.

[0065] This embodiment takes into account that the transmission speed of the signal in the actual RF transmission line is not completely equal to the speed of light in a vacuum, but there is an attenuation phenomenon. The attenuation is analyzed by the speed factor of the RF transmission line. The speed factor can be obtained by the annotation on the technical manual of the RF transmission line. In this embodiment, the speed factor of the RF transmission line to be tested is 0.95, and the implementer can also preset it. Therefore, in this embodiment, according to the time interval between the transmitted signal and the real tail end reflected pulse signal, combined with the vacuum light speed and the speed factor of the RF transmission line to be tested, the transmission length of the RF transmission line to be tested is obtained to calculate the length of the RF transmission line, specifically:

[0066] ; Where L represents the length of the RF transmission line to be tested, is the speed of light in vacuum, Indicates the speed factor of the RF transmission line to be tested. In actual application, implementers can obtain it from the technical manual of the RF transmission line or set it by themselves. Indicates the time interval between the transmitted signal and the actual tail end reflected pulse signal.

[0067] The calculated length of the RF transmission line is displayed through an oscilloscope, and the transmitted signal and the actual tail end reflected pulse signal are highlighted on the waveform display interface.

[0068] Based on the same inventive concept as the above method, an embodiment of the present application also provides a radio frequency transmission line length measurement system, including a memory, a processor, and a computer program stored in the memory and running on the processor, and when the processor executes the computer program, the steps of any one of the above-mentioned radio frequency transmission line length measurement methods are implemented.

[0069] It is to be understood that the sequence of the embodiments of the present application described above is for description only and does not represent the advantages and disadvantages of the embodiments. The above describes specific embodiments of the present specification. In addition, the processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0070] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

[0071] The above content is only an implementation method of the present application and is not intended to limit the scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly used in other related technical fields, are also included in the protection scope of the present application.

Claims

1. A method for measuring the length of a radio frequency transmission line, characterized in that: The following steps are involved: Obtain the transmission signal of the time domain reflectometer and the reflection signal of the RF transmission line to be tested; Performing baseline correction on the reflected signal and screening to obtain each reflected pulse signal, the signal intensity of each reflected pulse signal constitutes each reflected pulse sequence; According to the goodness of fit of the curve fitting of each reflected pulse sequence, combined with the similarity of the signal strength between the starting point and the first inflection point of the reflected pulse sequence and the signal strength between the last inflection point and the end point, the distortion degree of each reflected pulse signal is determined; Analyze the number of maximum values ​​on each curve after fitting and the fluctuation deviation of each maximum value to determine the pulse jump coefficient of each reflected pulse signal; Obtaining the reflection stability of each reflected pulse signal based on the distortion and pulse jump coefficient of each reflected pulse signal; Based on the correlation between each reflected pulse sequence and the transmitted signal, as well as the fundamental frequency difference and fundamental frequency energy intensity difference between each reflected pulse signal and the transmitted signal, combined with the reflection stability of each reflected pulse signal, the reflection determination coefficient of each reflected pulse signal is obtained; The real tail end reflection pulse signal is screened based on the numerical value of the reflection determination coefficient, and the transmission length of the RF transmission line to be tested is obtained according to the time interval between the transmitted signal and the real tail end reflection pulse signal, combined with the speed of light in vacuum and the preset speed factor of the RF transmission line to be tested.

2. A method for measuring the length of a radio frequency transmission line according to claim 1, characterized in that: Each reflected pulse signal further comprises: All signal intensities of the reflected signals are combined into a signal intensity sequence, and the signal intensity sequence is baseline corrected to obtain the signal intensity corresponding to the baseline , if the strength of a preset number of signals is greater than the screening threshold, the partial signal corresponding to the preset number of signal strengths is taken as a reflected pulse signal, where the screening threshold is .

3. A method for measuring the length of a radio frequency transmission line according to claim 1, characterized in that: The expression of the distortion of each reflected pulse signal is: ; Where B represents the distortion of the current reflected pulse signal, Indicates the goodness of fit of the current reflected pulse sequence curve, cos() indicates the cosine value, , They respectively represent the sequence composed of all signal intensities between the starting point and the first inflection point of the current reflected pulse sequence, and the sequence composed of all signal intensities between the last inflection point and the end point.

4. A method for measuring the length of a radio frequency transmission line according to claim 1, characterized in that: The pulse jump coefficient of each reflected pulse signal is the product of the number of maximum values ​​on each curve after fitting each reflected pulse sequence and the variance of all maximum values.

5. A method for measuring the length of a radio frequency transmission line according to claim 1, characterized in that: The expression of the reflection stability of each reflected pulse signal is: ; Where A, B, and C represent the reflection stability, distortion, and pulse jump coefficient of the current reflected pulse signal respectively; when , set the reflection stability to a value greater than 10.

6. A method for measuring the length of a radio frequency transmission line according to claim 1, characterized in that: The expression of the reflection determination coefficient of each reflected pulse signal is: ; In the formula, D and A represent the reflection determination coefficient and reflection stability of the current reflected pulse signal respectively, and They represent the transmitted pulse sequence and the reflected pulse sequence corresponding to the current reflected pulse signal, respectively. The transmitted pulse sequence is composed of all signal intensities of the transmitted signal. represents the Pearson correlation coefficient, and Indicates the fundamental frequency energy deviation and fundamental frequency deviation between the current reflected pulse signal and the transmitted signal.

7. A method for measuring the length of a radio frequency transmission line as claimed in claim 6, characterized in that: The fundamental frequency energy deviation is the difference between the fundamental frequency corresponding energy intensities of the current reflected pulse signal and the transmitted signal in the frequency domain, and the fundamental frequency deviation is the difference between the fundamental frequencies of the current reflected pulse signal and the transmitted signal in the frequency domain.

8. A method for measuring the length of a radio frequency transmission line according to claim 1, characterized in that: The real tail end reflected pulse signal is a reflected pulse signal corresponding to the maximum value of the reflection determination coefficient.

9. A method for measuring the length of a radio frequency transmission line according to claim 1, characterized in that: The expression of the transmission length of the radio frequency transmission line to be tested is: ; Where L represents the length of the RF transmission line to be tested, is the speed of light in vacuum, represents the velocity factor of the RF transmission line to be tested, Indicates the time interval between the transmitted signal and the actual tail end reflected pulse signal.

10. A radio frequency transmission line length measurement system, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 9 are implemented.

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