Method and apparatus for measuring relative lengths of multiway balanced feeders

Abstract

The application discloses a kind of multi-path balanced feeder relative length measurement method and device, method includes the feeder to be measured access test link, S parameter matrix is collected;S parameter matrix is fitted and handled, and phase slope is obtained;Based on the linear relationship of phase slope and feeder length, the relative length of balanced feeder is calculated;The application realizes the quick measurement of the relative length of multi-path balanced feeder, adapts batch production test, and compared with traditional manual measurement mode, test accuracy is also higher, environmental adaptability is better, can satisfy the requirement of high-precision system (such as phased array).

Description

Technical Field

[0001] This invention relates to the field of radio frequency and microwave testing technology, specifically to a method and apparatus for measuring the relative length of a multi-channel balanced feeder. Background Technology

[0002] In radio frequency systems, relative length deviations in multiple balanced feeders can lead to signal phase inconsistencies, severely impacting system performance (such as decreased antenna gain and beam pointing offset). Therefore, it is necessary to measure the relative lengths of multiple balanced feeders. Traditional measurement methods typically involve manual length measurement using convolution or a measuring tape. The drawbacks of these methods are:

[0003] (1) Insufficient accuracy: The length is measured manually using a tape measure or measuring tape, resulting in poor test accuracy. Furthermore, it is impossible to measure the influence of the environment and feeder routing on the phase, which cannot meet the requirements of high-precision systems (such as phased arrays).

[0004] (2) Inefficient: The length is measured manually using a tape measure or measuring tape. The measurement needs to be done in sections according to the feeder cable routing path, which takes a long time and is difficult to adapt to the needs of mass production.

[0005] (3) Poor environmental adaptability: Some shortwave feeder installation methods and installation environments are not suitable for measuring physical length manually.

[0006] In related technologies, patent application CN217504658U describes a measurement scheme for calculating cable length using a balun device; however, this scheme uses a signal source and oscilloscope to directly measure the length, which is greatly affected by the environment and the instability of the instrument. The document "Method for Debugging High-Power Shortwave Feeders Using a Network Analyzer," by Zheng Shibing, Computer Knowledge and Technology, proposes using a network analyzer to test the feeder and locate the fault point; this is essentially a debugging scheme rather than a testing and measurement scheme.

[0007] Therefore, there is an urgent need for a high-precision, high-efficiency, and widely applicable method for testing the relative length of multi-channel balanced feeders. Summary of the Invention

[0008] This invention aims to solve the problems of insufficient accuracy, low efficiency, and poor environmental adaptability in the relative length measurement of traditional multi-channel balanced feeders.

[0009] The present invention solves the above-mentioned technical problems through the following technical means: A method for measuring the relative length of multi-path balanced feeders is proposed, the method comprising: Connect the feeder under test to the test link and collect the S-parameter matrix; The phase slope is obtained by fitting the S-parameter matrix. The relative length of the balanced feeder is calculated based on the linear relationship between the phase slope and the feeder length.

[0010] Furthermore, the test link includes a vector network analyzer, a first attenuator, a second attenuator, a first balun, and a second balun. The first attenuator and the second attenuator are connected in series in two test ports of the vector network analyzer. The first balun is connected to the first attenuator via a phase-stable cable, and the second balun is connected to the second attenuator via a phase-stable cable. The impedance ratios of the first and second baluns are different.

[0011] Furthermore, the process of building the test link includes: A first attenuator and a second attenuator are connected in series at the first test port of the vector network analyzer. After connecting the phase-stabilized cables to the rear ends of the first and second attenuators respectively, perform SOLT calibration and store the calibration data; Connect the first balun to the first attenuator via a phase-stable cable, and connect the second balun to the second attenuator via a phase-stable cable.

[0012] Furthermore, the step of connecting the feeder under test to the test link and collecting the S-parameter matrix includes: Connect the XΩ main port of the feeder under test to the first balun and the YΩ branch port to the second balun. Connect the non-tested branch ports of the feeder under test to the corresponding impedance loads. The S-parameter matrix is ​​collected based on the set sweep frequency parameters.

[0013] Further, the step of acquiring the S-parameter matrix according to the set sweep frequency parameters includes: Based on the set sweep frequency parameters, the S-parameter matrix is ​​collected multiple times and the average value is taken.

[0014] Further, the fitting process of the S-parameter matrix to obtain the phase slope includes: The phase-frequency curve of the S-parameter matrix is ​​fitted using the weighted least squares method to obtain the phase slope, which is expressed by the formula:

[0015]

[0016] In the formula, Indicates phase, Indicates frequency, Indicates the phase slope, For constant terms; , For the first Frequency point phase noise variance , These are the average values ​​of frequency and phase, respectively. , The first The frequency and phase corresponding to the frequency point This represents the total number of frequency points.

[0017] Furthermore, the calculation of the relative length of the balanced feeder based on the linear relationship between the phase slope and the feeder length includes: Calculate the phase slope difference between the two feeder segments, and substitute it into the linear relationship based on the phase slope and feeder length to calculate the relative length of the balanced feeder. The linear relationship is expressed as:

[0018] In the formula, Indicates the relative length of the balanced feeder. This represents the speed of light in a vacuum. This represents the difference in phase slope between the two feed lines. Indicates the center frequency of the sweep frequency. This indicates the sweep bandwidth.

[0019] Furthermore, this invention also proposes a multi-path balanced feeder relative length measurement device, the device comprising a test link and a length measurement module, wherein the feeder under test is connected to the test link, and the output of the test link is connected to the length measurement module, the length measurement module comprising: The acquisition unit is used to acquire the S-parameter matrix; The fitting unit is used to fit the S-parameter matrix to obtain the phase slope. The length calculation unit is used to calculate the relative length of the balanced feeder based on the linear relationship between the phase slope and the feeder length.

[0020] Furthermore, the test link includes a vector network analyzer, a first attenuator, a second attenuator, a first balun, and a second balun. The first attenuator and the second attenuator are connected in series in two test ports of the vector network analyzer. The first balun is connected to the first attenuator via a phase-stable cable, and the second balun is connected to the second attenuator via a phase-stable cable. The impedance ratios of the first and second baluns are different.

[0021] Furthermore, the fitting unit is specifically used for: The phase-frequency curve of the S-parameter matrix is ​​fitted using the weighted least squares method to obtain the phase slope, which is expressed by the formula:

[0022]

[0023] In the formula, Indicates phase, Indicates frequency, Indicates the phase slope, For constant terms; , For the first Frequency point phase noise variance , These are the average values ​​of frequency and phase, respectively. , The first The frequency and phase corresponding to the frequency point This represents the total number of frequency points.

[0024] The advantages of this invention are: (1) This invention obtains the S-parameter matrix by connecting the feeder under test to the test link, and obtains the phase slope by fitting the phase data in the S-parameter matrix. Based on the linear relationship between the phase slope and the feeder length, the relative length of the balanced feeder is calculated, thereby realizing the rapid measurement of the relative length of multiple balanced feeders. It is suitable for mass production testing, and compared with the traditional manual measurement method, the test accuracy is also higher, the environmental adaptability is better, and it can meet the requirements of high-precision systems (such as phased arrays).

[0025] (2) The test link used in this invention is configured with dual attenuators and dual baluns. By adding attenuators, the reflection coefficient is reduced, and by setting baluns with different impedance ratios, it is compatible with XΩ and YΩ balanced feeders, thus solving the problem of single impedance of traditional fixtures. The phase fluctuation is reduced from ±15° to ±1.5° by the dual attenuator-dual balun structure. Combined with the phase slope method, the relative length test accuracy reaches ±0.1%, which meets the requirements of high-precision systems.

[0026] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0027] The accompanying drawings, which form part of this specification, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation thereof. Figure 1 This is a flowchart illustrating a method for measuring the relative length of a multi-path balanced feeder according to an embodiment of the present invention. Figure 2 This is a schematic diagram of the test link structure in one embodiment of the present invention; Figure 3 This is a measured diagram of the phase and length relationship between branches 1 to 8 in one embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of a multi-channel balanced feeder relative length measuring device according to an embodiment of the present invention. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] like Figure 1 As shown, the first embodiment of the present invention proposes a method for measuring the relative length of a multi-path balanced feeder, the method comprising the following steps: S10. Connect the feeder under test to the test link and collect the S-parameter matrix; S20. Fit the S-parameter matrix to obtain the phase slope; S30. Calculate the relative length of the balanced feeder based on the linear relationship between the phase slope and the feeder length.

[0030] It should be noted that this embodiment obtains the S-parameter matrix by connecting the feeder under test to the test link. The S-parameter matrix contains amplitude and phase, and the phase data in the S-parameter matrix is ​​fitted to obtain the phase slope. Based on the linear relationship between the phase slope and the feeder length, the relative length of the balanced feeder is calculated, thereby realizing the rapid measurement of the relative length of multiple balanced feeders. This method is suitable for mass production testing and has higher testing accuracy and better environmental adaptability compared with traditional manual measurement methods. It can meet the requirements of high-precision systems (such as phased arrays).

[0031] As a further preferred technical solution, such as Figure 2 As shown, the test link includes a vector network analyzer, a first attenuator, a second attenuator, a first balun, and a second balun. The first attenuator and the second attenuator are connected in series in two test ports of the vector network analyzer. The first balun is connected to the first attenuator via a phase-stable cable, and the second balun is connected to the second attenuator via a phase-stable cable. The impedance ratios of the first and second baluns are different.

[0032] It should be noted that this embodiment improves link performance through two-stage optimization. Specifically, a first attenuator and a second attenuator are connected in series at the outputs of test ports Port1 and Port2 of the vector network analyzer, respectively. Both the first and second attenuators are 10dB attenuators. By setting up dual attenuators, the port reflection coefficient can be reduced, and the VSWR=4 without attenuators can be reduced to VSWR=1.22, reducing the interference of reflected signals on phase measurements. Furthermore, through dual attenuation (total attenuation of 20dB), mismatch energy is attenuated, and spurious signals introduced by balun impedance mismatch are suppressed.

[0033] The first balun is connected to the first attenuator via a phase-stabilized cable, and the second balun is connected to the second attenuator via a phase-stabilized cable. That is, the back end of test port Port1 is connected to a 1:X / 50 balun (50Ω unbalanced end, XΩ balanced end), which is compatible with XΩ balanced feeders; the back end of test port Port2 is connected to a 1:Y / 50 balun (50Ω unbalanced end, YΩ balanced end), which is compatible with YΩ balanced feeders. By combining 1:X / 50 and 1:Y / 50 baluns, it is compatible with XΩ and YΩ balanced feeders, solving the problem of single impedance of traditional clamps.

[0034] As a further preferred technical solution, the balun structure set in this embodiment needs to meet the requirements of phase balance within the frequency band ±1° and insertion loss ≤0.5dB.

[0035] As a further preferred technical solution, the process of building the test link includes: A first attenuator and a second attenuator are connected in series at the first test port of the vector network analyzer. After connecting the phase-stabilized cables to the rear ends of the first and second attenuators respectively, perform SOLT calibration and store the calibration data; Connect the first balun to the first attenuator via a phase-stable cable, and connect the second balun to the second attenuator via a phase-stable cable.

[0036] Specifically, in this embodiment, a 10dB attenuator is first installed in series on test ports Port1 and Port2 of the vector network analyzer. After connecting a phase-stable cable to the back end of the attenuator, SOLT calibration (short-circuit-open-load-straight-through) is performed and the calibration data is stored. Then, a 1:4 balun is connected to the test cable on test port Port1 and a 1:6 balun is connected to the test cable on test port Port2.

[0037] The parameter requirements for each device in the test link are shown in Table 1: Table 1 Equipment Parameter Requirements

[0038] As a further preferred technical solution, step S10: connecting the feeder under test to the test link and collecting the S-parameter matrix specifically includes the following steps: S101. Connect the XΩ main port of the feeder under test to the first balun and the YΩ branch port to the second balun. Connect the non-tested branch ports of the feeder under test to the corresponding impedance loads. S102. Collect the S-parameter matrix according to the set sweep frequency parameters.

[0039] It should be noted that during the specific testing, the feeder under test is connected as follows: the XΩ main port of the T-section under test is connected to a 1:4 balun, the YΩ branch port under test is connected to a 1:6 balun, and the non-under-test 300Ω branch port is connected to a 300Ω impedance load; the frequency sweep parameters are set as follows: frequency band, 1601 points, measuring the S21 phase (unit: degree), collecting 8 channels of data, and continuously collecting 3 times for each channel and taking the average value to reduce noise.

[0040] As a further orderly technical solution, step S20: fitting the S-parameter matrix to obtain the phase slope, specifically includes the following steps: The phase-frequency curve of the S-parameter matrix is ​​fitted using the weighted least squares method to obtain the phase slope, which is expressed by the formula:

[0041]

[0042] In the formula, Indicates phase, Indicates frequency, Indicates the phase slope (° / MHz). For constant terms; , For the first Frequency point phase noise variance , These are the average values ​​of frequency and phase, respectively. , The first The frequency and phase corresponding to the frequency point This represents the total number of frequency points.

[0043] It should be noted that the fitting result is determined as the phase slope when the goodness of fit satisfies R² ≥ 0.998.

[0044] As a further preferred technical solution, step S30: calculating the relative length of the balanced feeder based on the linear relationship between the phase slope and the feeder length, specifically includes the following steps: Calculate the phase slope difference between the two feeder segments, and substitute it into the linear relationship based on the phase slope and feeder length to calculate the relative length of the balanced feeder. The linear relationship is expressed as:

[0045] In the formula, Indicates the relative length of the balanced feeder; The speed of light in a vacuum is 2.99792458 × 10⁻⁶. 8 m / s); This represents the phase slope difference (° / MHz) between the two feed lines. Indicates the center frequency of the sweep frequency (MHz). =(fstart+fend) / 2; Indicates the sweep bandwidth (MHz). =fend-fstart.

[0046] It should be noted that this embodiment achieves high-precision testing through test link optimization, phase data acquisition and fitting processing, and relative length calculation. By employing a double-attenuation-double-balun structure, phase fluctuations are reduced from ±15° to ±1.5°. Combined with the phase slope method, the relative length testing accuracy reaches ±0.1%, meeting the requirements of high-precision systems. The testing time is shortened from 48 hours to 8 hours, improving efficiency by four times, making it suitable for mass production testing. This embodiment uses vector network analysis (VNA) testing and considers reducing the impact of environmental and instrument instability in the designed test link. Furthermore, data post-processing is added to enhance test stability. It is particularly suitable for RF system testing scenarios such as shortwave communication and broadcasting, where strict control of feeder length consistency is required. In shortwave broadcasting systems, it can efficiently and accurately test the relative length of the feeder system, providing a possibility for phase compensation.

[0047] The results obtained using the measurement method of this embodiment are as follows: Figure 3 As shown in Table 2, the measurement performance is compared with that obtained by traditional manual measurement methods: Table 2 Comparison of Experimental Results

[0048] In addition, such as Figure 4 As shown, the second embodiment of the present invention also proposes a multi-path balanced feeder relative length measurement device. The device includes a test link 10 and a length measurement module 20. The feeder under test is connected to the test link 10, and the output of the test link 10 is connected to the length measurement module 20. The length measurement module 20 includes: Acquisition unit 21 is used to acquire the S-parameter matrix; Fitting unit 22 is used to fit the S-parameter matrix to obtain the phase slope; The length calculation unit 23 is used to calculate the relative length of the balanced feeder based on the linear relationship between the phase slope and the feeder length.

[0049] As a further preferred technical solution, the test link 10 includes a vector network analyzer, a first attenuator, a second attenuator, a first balun, and a second balun. The first attenuator and the second attenuator are connected in series in two test ports of the vector network analyzer. The first balun is connected to the first attenuator via a phase-stable cable, and the second balun is connected to the second attenuator via a phase-stable cable. The impedance ratios of the first and second baluns are different.

[0050] As a preferred technical solution, the fitting unit 22 is specifically used for: The phase-frequency curve of the S-parameter matrix is ​​fitted using the weighted least squares method to obtain the phase slope, which is expressed by the formula:

[0051]

[0052] In the formula, Indicates phase, Indicates frequency, Indicates the phase slope, For constant terms; , For the first Frequency point phase noise variance , These are the average values ​​of frequency and phase, respectively. , The first The frequency and phase corresponding to the frequency point This represents the total number of frequency points.

[0053] As a further technical solution, the length calculation unit 23 is specifically used for: The phase-frequency curve of the S-parameter matrix is ​​fitted using the weighted least squares method to obtain the phase slope, which is expressed by the formula:

[0054]

[0055] In the formula, Indicates phase, Indicates frequency, Indicates the phase slope, For constant terms; , For the first Frequency point phase noise variance , These are the average values ​​of frequency and phase, respectively. , The first The frequency and phase corresponding to the frequency point This represents the total number of frequency points.

[0056] It should be noted that other embodiments or specific implementation methods of the multi-channel balanced feeder relative length measuring device of the present invention can refer to the above-described method embodiments, and will not be repeated here.

[0057] It should be noted that the computer-readable medium disclosed in this embodiment may be a computer-readable signal medium or a computer-readable storage medium, or any combination thereof. A computer-readable storage medium may be, for example,—but not limited to—an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of a computer-readable storage medium may include, but are not limited to: an electrical connection having one or more wires, a portable computer disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, and portable compact disk read-only memory (CD-ROM). ROM, optical storage devices, magnetic storage devices, or any suitable combination thereof. In this disclosure, a computer-readable storage medium can be any tangible medium containing or storing a program that can be used by or in connection with an instruction execution system, apparatus, or device. In this disclosure, a computer-readable signal medium can include a data signal propagated in baseband or as part of a carrier wave, carrying computer-readable program code. Such propagated data signals can take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. A computer-readable signal medium can also be any computer-readable medium other than a computer-readable storage medium, which can send, propagate, or transmit a program for use by or in connection with an instruction execution system, apparatus, or device. The program code contained on the computer-readable medium can be transmitted using any suitable medium, including but not limited to: wires, optical fibers, RF (radio frequency), etc., or any suitable combination thereof.

[0058] The aforementioned computer-readable medium may be included in the aforementioned electronic device; or it may exist independently and not assembled into the electronic device. The aforementioned computer-readable medium carries one or more programs, which, when executed by the electronic device, cause the electronic device to perform a zero-sample image anomaly detection method according to the above embodiments.

[0059] Computer program code for performing the operations of this disclosure can be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, and C++, and conventional procedural programming languages ​​such as the "C" language or similar programming languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server.

[0060] In cases involving remote computers, the remote computer can be connected to the user's computer via any type of network—including a local area network (LAN) or a wide area network (WAN), or it can be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0061] It should be understood that various parts of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0062] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0063] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" or "several" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0064] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for measuring the relative length of a multi-path balanced feeder, characterized in that, include: Connect the feeder under test to the test link and collect the S-parameter matrix; The phase slope is obtained by fitting the S-parameter matrix. The relative length of the balanced feeder is calculated based on the linear relationship between the phase slope and the feeder length.

2. The method for measuring the relative length of multi-channel balanced feeders as described in claim 1, characterized in that, The test link includes a vector network analyzer, a first attenuator, a second attenuator, a first balun, and a second balun. The first attenuator and the second attenuator are connected in series in two test ports of the vector network analyzer. The first balun is connected to the first attenuator via a phase-stable cable, and the second balun is connected to the second attenuator via a phase-stable cable. The impedance ratios of the first and second baluns are different.

3. The method for measuring the relative length of multi-channel balanced feeders as described in claim 2, characterized in that, The process of setting up the test link includes: A first attenuator and a second attenuator are connected in series at the first test port of the vector network analyzer. After connecting the phase-stabilized cables to the rear ends of the first and second attenuators respectively, perform SOLT calibration and store the calibration data; Connect the first balun to the first attenuator via a phase-stable cable, and connect the second balun to the second attenuator via a phase-stable cable.

4. The method for measuring the relative length of multi-channel balanced feeders as described in claim 2, characterized in that, The step of connecting the feeder under test to the test link and collecting the S-parameter matrix includes: Connect the XΩ main port of the feeder under test to the first balun and the YΩ branch port to the second balun. Connect the non-tested branch ports of the feeder under test to the corresponding impedance loads. The S-parameter matrix is ​​collected based on the set sweep frequency parameters.

5. The method for measuring the relative length of a multi-channel balanced feeder as described in claim 4, characterized in that, The step of acquiring the S-parameter matrix according to the set frequency sweep parameters includes: Based on the set sweep frequency parameters, the S-parameter matrix is ​​collected multiple times and the average value is taken.

6. The method for measuring the relative length of multi-channel balanced feeders as described in claim 1, characterized in that, The process of fitting the S-parameter matrix to obtain the phase slope includes: The phase-frequency curve of the S-parameter matrix is ​​fitted using the weighted least squares method to obtain the phase slope, which is expressed by the formula: In the formula, Indicates phase, Indicates frequency, Indicates the phase slope, For constant terms; , For the first Frequency point phase noise variance , These are the average values ​​of frequency and phase, respectively. , The first The frequency and phase corresponding to the frequency point This represents the total number of frequency points.

7. The method for measuring the relative length of multi-channel balanced feeders as described in claim 1, characterized in that, The calculation of the relative length of the balanced feeder based on the linear relationship between the phase slope and the feeder length includes: Calculate the phase slope difference between the two feeder segments, and substitute it into the linear relationship based on the phase slope and feeder length to calculate the relative length of the balanced feeder. The linear relationship is expressed as: In the formula, Indicates the relative length of the balanced feeder. This represents the speed of light in a vacuum. This represents the difference in phase slope between the two feed lines. Indicates the center frequency of the sweep frequency. This indicates the sweep bandwidth.

8. A device for measuring the relative length of a multi-channel balanced feeder, characterized in that, The system includes a test link and a length measurement module. The feeder under test is connected to the test link, and the output of the test link is connected to the length measurement module. The length measurement module includes: The acquisition unit is used to acquire the S-parameter matrix; The fitting unit is used to fit the S-parameter matrix to obtain the phase slope. The length calculation unit is used to calculate the relative length of the balanced feeder based on the linear relationship between the phase slope and the feeder length.

9. The multi-channel balanced feeder relative length measuring device as described in claim 8, characterized in that, The test link includes a vector network analyzer, a first attenuator, a second attenuator, a first balun, and a second balun. The first attenuator and the second attenuator are connected in series in two test ports of the vector network analyzer. The first balun is connected to the first attenuator via a phase-stable cable, and the second balun is connected to the second attenuator via a phase-stable cable. The impedance ratios of the first and second baluns are different.

10. The multi-channel balanced feeder relative length measuring device as described in claim 8, characterized in that, The fitting unit is specifically used for: The phase-frequency curve of the S-parameter matrix is ​​fitted using the weighted least squares method to obtain the phase slope, which is expressed by the formula: In the formula, Indicates phase, Indicates frequency, Indicates the phase slope, For constant terms; , For the first Frequency point phase noise variance , These are the average values ​​of frequency and phase, respectively. , The first The frequency and phase corresponding to the frequency point This represents the total number of frequency points.

Images