A test tool for NMD flange connector and a test method thereof

Abstract

This invention relates to the field of performance testing technology, and more particularly to a testing fixture and method for NMD flange connectors. The invention connects one end of the NMD flange connector to the product under test via a detection unit, and the inner conductor of the other side of the NMD flange adapter is connected to the inner conductor of a vector network analyzer. The outer conductor of the vector network analyzer is fixed to the flange of the NMD flange adapter, enabling signal transmission with low loss and low reflection. A calculation unit determines the reflection loss value based on the detection data received from the detection unit, and an analysis unit determines the test state based on the average reflection loss value over a preset period, adjusting relevant parameters accordingly. This invention improves the efficiency of electrical performance testing of NMD flange connectors.

Description

Technical Field

[0001] This invention relates to the field of performance testing technology, and in particular to a testing fixture and testing method for NMD flange connectors. Background Technology

[0002] In the field of radio frequency and microwave testing, especially when using vector network analyzers (VNAs) for high-precision S-parameter measurements, the performance of the connection port is crucial. NMD (Network Measurements Division) flange connectors, with their superior characteristics, are ideal for such high-end applications. The core advantage of NMD connectors lies in their exceptional mechanical stability and electrical consistency. Their precise threaded connection mechanism ensures excellent repeatability and connection stability, effectively eliminating errors introduced during testing due to loosening or changes in the connection. This is essential for VNA testing, which requires extremely high measurement accuracy and stability, especially in the millimeter-wave band. Their low reflection coefficient (low VSWR) and low loss characteristics minimize signal distortion, ensuring the authenticity and reliability of measurement results. However, some instrument panel-mounted NMD connectors have a standard connector interface on one end, where the outer conductor is fixed and mated via a threaded sleeve, while the other end is an open end with the inner conductor exposed. Under normal circumstances, it is impossible to properly test the actual electrical performance of the product.

[0003] Chinese Patent Publication No. CN102882591A discloses a test fixture for a PLC optical splitter, including a bracket and flanges. The bracket has slots, and multiple flanges are fixed on the bracket by being arranged in parallel through the slots.

[0004] Therefore, it is evident that the existing technology has the following problem: low efficiency in testing the electrical performance of NMD flange connectors. Summary of the Invention

[0005] Therefore, the present invention provides a testing fixture and testing method for NMD flange connectors to overcome the problem of low efficiency in testing the electrical performance of NMD flange connectors in the prior art.

[0006] To achieve the above objectives, the present invention provides a testing fixture for NMD flange connectors, comprising:

[0007] The testing unit includes an NMD flange adapter, a vector network analyzer, and a fixing fixture, used to test the transmission signal of the NMD flange connector to be tested. The first end of the NMD flange adapter is fixed to the NMD flange interface of the product to be tested via a threaded connection. The inner conductor of the second end of the NMD flange adapter has a countersunk hole and the inner conductor of the periodically calibrated vector network analyzer is coaxially connected via an elastic pin. The outer conductor connected to the vector network analyzer is fixed to the flange of the NMD flange adapter.

[0008] A calculation unit, connected to the detection unit, is used to receive detection data transmitted by the detection unit and to determine the reflection loss value based on the detection data.

[0009] An analysis unit, connected to the calculation unit, is used to determine the test state based on the average value of the reflection loss value within a preset period, and to adjust the calibration period of the vector network analyzer and the reflection loss value based on the test state.

[0010] Furthermore, the analysis unit is also used to obtain reflection loss values ​​corresponding to multiple moments in a preset period when the test state is determined to be unqualified; the analysis unit is also used to calculate the variance of the reflection loss values ​​corresponding to multiple moments in the preset period, and, when the variance is less than the preset variance, adjust the calibration period of the vector network analyzer based on the ratio of the variance to the preset variance; wherein, if the average value of the reflection loss values ​​is less than the preset average value, the test state is determined to be unqualified.

[0011] Furthermore, the analysis unit is also used to reduce the calibration cycle of the vector network analyzer based on the ratio of the variance to the preset variance, and the reduction in the calibration cycle is inversely proportional to the ratio.

[0012] Furthermore, the calculation unit also includes a calibration module, which is used to correct the reflection loss value based on the deviation value; the calibration module is also used to correct the reflection loss value based on the first reflection loss value = reflection loss value + deviation value, wherein, In the formula, The current reflection loss value is the difference between the reflection loss value when the vector network analyzer was calibrated, and T is the time difference between the current value and the last time the vector network analyzer was calibrated. This refers to the adjusted calibration cycle for the vector network analyzer.

[0013] Furthermore, the analysis unit is also used to readjust the reflection loss value at least once if the test status is unqualified after correcting the reflection loss value, until the number of adjustments is less than a preset number and the test status is qualified, or the number of adjustments is equal to the preset number and the adjustment stops; the analysis unit is also used to plot a historical period-average value curve based on the average value of the reflection loss value obtained in multiple historical periods if the test status is unqualified after stopping the adjustment; the analysis unit is also used to adjust the axial mating distance of the connector based on the ratio of the integral to the preset integral if the integral of the curve is less than a preset integral.

[0014] Furthermore, the analysis unit is also used to increase the axial mating distance of the connector based on the ratio of the integral to the preset integral, and the increase in the axial mating distance of the connector is inversely proportional to the ratio.

[0015] Furthermore, the analysis unit is also used to plot a reflection loss value-frequency curve based on the frequencies corresponding to multiple reflection loss values ​​within a preset period when the test state is unqualified after adjusting the axial mating distance of the connector; the analysis unit is also used to calculate the average value of the absolute values ​​of the slopes corresponding to multiple coordinate points of the curve, and to issue a calibration interface notification when the average value is less than a preset value.

[0016] Furthermore, the analysis unit is also used to obtain the -3dB bandwidth of the peak of the preset frequency on the input reflection coefficient curve in the vector network analyzer when the energy storage state is unqualified after the calibration interface; the analysis unit is also used to adjust the frequency step of the frequency band where the -3dB bandwidth is less than the preset average value based on the ratio of the average value to the preset average value when the average value of the bandwidth is less than the preset average value.

[0017] Furthermore, the analysis unit is also used to reduce the frequency step of the band with a bandwidth less than the preset average value by -3dB based on the ratio of the average value to the preset average value, and the reduction of the frequency step is inversely proportional to the ratio.

[0018] To achieve the above objectives, the present invention provides a testing method, which is applied to any of the above-described testing fixtures for NMD flange connectors, comprising:

[0019] The transmission signal of the NMD flange connector to be tested is detected by a testing unit including an NMD flange adapter, a vector network analyzer, and a fixing fixture. The first end of the NMD flange adapter is fixed to the NMD flange interface of the product to be tested by a threaded connection. The inner conductor of the second end of the NMD flange adapter has a countersunk hole and the inner conductor of the periodically calibrated vector network analyzer is coaxially connected by an elastic pin. The outer conductor connected to the vector network analyzer is fixed on the flange of the NMD flange adapter.

[0020] The computing unit connected to the detection unit receives the detection data transmitted by the detection unit and determines the reflection loss value based on the detection data.

[0021] The analysis unit connected to the computing unit determines the test state based on the average value of the reflection loss value within a preset period, and adjusts the calibration period of the vector network analyzer and the reflection loss value based on the test state.

[0022] Compared with existing technologies, the advantages of this invention are as follows: This invention connects one end of the NMD flange connector to the product under test via a detection unit, connects the inner conductor of the other side of the NMD flange adapter to the inner conductor of a vector network analyzer, and fixes the outer conductor of the vector network analyzer to the flange of the NMD flange adapter. This enables signal transmission with low loss and low reflection. Furthermore, a calculation unit determines the reflection loss value based on the detection data received from the detection unit; and an analysis unit determines the test state based on the average reflection loss value over a preset period, and adjusts relevant parameters based on the test state. This invention improves the efficiency of electrical performance testing of NMD flange connectors.

[0023] Furthermore, the present invention determines the cause of the test failure by averaging the reflection loss values ​​at multiple moments within a preset period, which can more accurately identify the cause and enable more precise subsequent adjustments, thereby further improving the efficiency of electrical performance testing of NMD flange connectors.

[0024] Furthermore, this invention adjusts the calibration cycle of the vector network analyzer based on the ratio of variance to preset variance. This allows for timely calibration of the vector network analyzer, thereby more accurately measuring the reflection coefficient and determining the reflection loss value more precisely. This further improves the efficiency of electrical performance testing of NMD flange connectors.

[0025] Furthermore, this invention dynamically adjusts the deviation value in the calibration module based on the calibration cycle of a vector network analyzer, thereby more accurately determining the reflection loss value, more accurately analyzing the test status, and further improving the efficiency of electrical performance testing of NMD flange connectors.

[0026] Furthermore, this invention determines the cause of test failure based on the integral of the historical period-average curve, enabling more accurate adjustment of relevant parameters based on more precise causes, thereby further improving the efficiency of electrical performance testing of NMD flange connectors.

[0027] Furthermore, the present invention increases the axial mating distance of the connector based on the ratio of the integral to the preset integral, which can indirectly increase the pressure of the elastic pin, enabling the two inner conductors to successfully mate, thereby further improving the efficiency of electrical performance testing of NMD flange connectors.

[0028] Furthermore, this invention determines the cause of test failure based on the average of the absolute values ​​of the slopes corresponding to multiple coordinate points on the reflection loss-frequency curve. This allows for more accurate adjustment of relevant parameters based on more precise causes, thereby further improving the efficiency of electrical performance testing of NMD flange connectors.

[0029] Furthermore, this invention determines the cause of unqualified energy storage status based on the average value of the -3dB bandwidth of the peak of the preset frequency on the input reflection coefficient curve in the vector network analyzer. It can determine whether the unqualified energy storage status is due to external interference, so as to make more accurate adjustments to relevant parameters based on more accurate causes, thereby further improving the efficiency of electrical performance testing of NMD flange connectors.

[0030] Furthermore, the present invention reduces the frequency step of the frequency band with a bandwidth less than the preset average value by -3dB based on the ratio of the average value to the preset average value. This can reduce the influence of external interference on the measurement results, thereby making the reflection loss value determined based on the measurement coefficient of the vector network analyzer more accurate, so as to more accurately determine the test state, and further improve the efficiency of electrical performance testing of NMD flange connectors. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the test fixture used for NMD flange connectors according to an embodiment of the present invention;

[0032] Figure 2 A schematic diagram showing how an integral flange can be disassembled into two threaded structural parts;

[0033] Figure 3 An enlarged view of the structure of the integrated flange after the second flange has been removed;

[0034] Figure 4 Flowchart of the NMD adapter test fixture assembly process;

[0035] Figure 5 This is a flowchart illustrating the steps of a test method using a test fixture for NMD flange connectors according to an embodiment of the present invention.

[0036] Figure 6 This is a flowchart illustrating the steps of determining the reflection loss based on the comparison between the average value of the reflection loss within a preset period and the preset average value in an embodiment of the present invention.

[0037] Figure 7This is a flowchart illustrating the steps for determining the test status based on the corrected reflection loss value in an embodiment of the present invention. Detailed Implementation

[0038] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0039] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0040] It should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0041] Please see Figure 1 As shown, it is a structural schematic diagram of a test fixture for NMD flange connectors according to an embodiment of the present invention.

[0042] The system includes a detection unit, a calculation unit, and an analysis unit.

[0043] The detection unit includes an NMD flange adapter, a vector network analyzer, and a fixing fixture, which is used to detect the transmission signal of the NMD flange connector to be tested. The first end of the NMD flange adapter is fixed to the NMD flange interface of the product to be tested via a threaded connection. The inner conductor of the second end of the NMD flange adapter has a countersunk hole and the inner conductor of the periodically calibrated vector network analyzer is coaxially connected via an elastic pin. The outer conductor connected to the vector network analyzer is fixed on the flange of the NMD flange adapter.

[0044] The computing unit is connected to the detection unit and is used to receive detection data transmitted by the detection unit and to determine the reflection loss value based on the detection data.

[0045] The analysis unit is connected to the calculation unit and is used to determine the test state based on the average value of the reflection loss value within a preset period, and to adjust the calibration period of the vector network analyzer and the reflection loss value based on the test state.

[0046] Specifically, such as Figure 2As shown, this is a schematic diagram of a one-piece flange being disassembled into two threaded structural parts, using double insulation support. The one-piece flange is divided into two independent parts: a first flange 7 and a second flange 11, as follows. Figure 3 As shown, this is an enlarged view of the structure of the integrated flange after the second flange has been removed. Based on the original NMD flange connector, two new test fixture parts are made: the test connection inner conductor and the test connection outer conductor. The NMD flange connector test fixture consists of a total of 10 parts: NMD threaded sleeve 1, NMD outer conductor 2, insulator 3, C-type retaining ring 4, small body 5, NMD inner conductor 6, first flange 7, connection insulator 8, test connection outer conductor 9, and test connection inner conductor 10.

[0047] Specifically, such as Figure 4 The diagram shown is a flowchart of the NMD adapter testing fixture assembly process. The specific steps are as follows:

[0048] Step 1: Remove the second flange from the NMD flange connector in its initial state;

[0049] Step 2: Insert the test fixture's test connection inner conductor into the NMD inner conductor of the NMD flange connector;

[0050] Step 3: Screw the outer conductor of the test fixture onto the first flange of the NMD flange connector. At this point, the NMD flange connector is transformed into an NMD flange adapter by adding the fixture accessories.

[0051] Step 4: Connect the NMD flange adapter to the vector network analyzer for testing. After the test is completed, remove the outer and inner test conductors of the test connection on the NMD flange adapter, and screw the second flange back onto the first flange.

[0052] Specifically, the formula for calculating the reflection loss value RL is as follows:

[0053] ;

[0054] In the formula, For incident power, This represents the reflected power.

[0055] Please see Figure 5 As shown, it is a flowchart of the testing method of the testing fixture for NMD flange connectors according to an embodiment of the present invention.

[0056] The specific testing procedures for NMD flange connectors are as follows:

[0057] S1, the transmission signal of the NMD flange connector to be tested is detected by a testing unit including an NMD flange adapter, a vector network analyzer and a fixing fixture. The first end of the NMD flange adapter is fixed to the NMD flange interface of the product to be tested by a threaded connection. The inner conductor of the second end of the NMD flange adapter has a countersunk hole and the inner conductor of the periodically calibrated vector network analyzer is coaxially connected by an elastic pin. The outer conductor connected to the vector network analyzer is fixed on the flange of the NMD flange adapter.

[0058] S2, receiving detection data transmitted by the detection unit through a computing unit connected to the detection unit, and determining the reflection loss value based on the detection data;

[0059] S3, the analysis unit connected to the computing unit determines the test state based on the average value of the reflection loss value within a preset period, and adjusts the calibration period of the vector network analyzer and the reflection loss value based on the test state.

[0060] Please see Figure 6 As shown, it is a flowchart of the steps for determining the reflection loss based on the comparison between the average value of the reflection loss within a preset period and the preset average value in an embodiment of the present invention.

[0061] Specifically, the testing fixture adopts a data-driven parameter optimization mechanism, which uses statistical analysis of a large amount of historical test data to set the values ​​of subsequent preset or critical parameters.

[0062] Specifically, if the preset average value L0 = 20dB, the comparison process between the average value L of the reflection loss within the preset period and the preset average value L0 is as follows:

[0063] If the average reflection loss L within the preset period is greater than or equal to the preset average value L0, the test status is deemed qualified.

[0064] If the average reflection loss L within the preset period is less than the preset average value L0, the test condition is determined to be unqualified.

[0065] Specifically, when the test condition is determined to be unqualified, the reflection loss values ​​at multiple times within a preset period are obtained; the variance of the multiple reflection loss values ​​is calculated. If the variance is less than the preset variance, it indicates that the measured reflection power is consistently high, causing the reflection loss value to remain consistently low, thus making the test condition unqualified. The calibration period of the vector network analyzer is then adjusted based on the ratio of the variance to the preset variance. The preset ratio of the variance to the preset variance, P0 = 0.76. The comparison process between the variance to the preset variance P and the preset ratio P0 is as follows:

[0066] If the ratio P of the variance to the preset variance is less than or equal to the preset ratio P0, the calibration cycle of the vector network analyzer will be adjusted to 0.62 times the original calibration cycle, and the adjusted value will be rounded up.

[0067] If the ratio P of the variance to the preset variance is greater than the preset ratio P0, the calibration cycle of the vector network analyzer will be adjusted to 0.79 times the original calibration cycle, with the adjusted value rounded up.

[0068] Specifically, the calculation unit also includes a calibration module. The deviation value in the calibration module is used to correct the calculated reflection loss value to determine a first reflection loss value. The first reflection loss value is the corrected reflection loss value, which is the sum of the reflection loss value and the deviation value. In the formula, The current reflection loss value is the difference between the reflection loss value when the vector network analyzer was calibrated, and T is the time difference between the current value and the last time the vector network analyzer was calibrated. The adjusted calibration cycle of the vector network analyzer allows for more accurate correction of reflection loss values.

[0069] Please see Figure 7 As shown, it is a flowchart of the steps for determining the test status based on the corrected reflection loss value in an embodiment of the present invention.

[0070] Specifically, if the test status is unqualified after correcting the reflection loss value, the reflection loss value is readjusted at least once until the number of adjustments is less than the preset number and the test status is qualified, or the number of adjustments is equal to the preset number, at which point the adjustment stops. If the test status is unqualified after stopping the adjustment, a historical period-average value curve is plotted based on the average of the reflection loss values ​​obtained over multiple historical periods. If the integral of the curve is less than the preset integral, it indicates that the pressure of the elastic pin is insufficient and cannot allow the two inner conductors to successfully mate. Then, the axial mating distance of the connector is adjusted based on the ratio of the integral to the preset integral. The preset ratio Q0 is 0.87. The comparison process between the ratio Q and the preset ratio Q0 is as follows:

[0071] If the ratio Q of the integral to the preset integral is less than or equal to the preset ratio Q0, the axial mating distance of the connector will be adjusted to 2.53 times the original axial mating distance, where the adjusted axial mating distance is rounded up.

[0072] If the ratio Q of the integral to the preset integral is greater than the preset ratio Q0, the axial mating distance of the connector will be adjusted to 1.83 times the original axial mating distance, where the adjusted axial mating distance is rounded up.

[0073] Specifically, if the test results are still unsatisfactory after adjusting the axial mating distance of the connector, the frequencies corresponding to multiple reflection loss values ​​within the preset period are obtained, and a reflection loss value-frequency curve is plotted. The average slope of multiple coordinate points on the curve is calculated. If the average value is less than the preset value, it indicates that the reflection loss is poor throughout the entire frequency band, and the curve is generally low and relatively flat. In this case, a calibration interface notification is issued.

[0074] Specifically, when the energy storage state is unqualified after interface calibration, the -3dB bandwidth of the peak at a preset frequency on the S11 curve of the vector network analyzer is obtained. The S11 curve is the reflection coefficient curve measured by the vector network analyzer, representing the ratio of the signal incident from the device port to the signal reflected from the same device port; that is, the curve showing the reflection coefficient as a function of frequency measured by the vector network analyzer. If the average bandwidth is less than the preset average, it indicates the presence of external interference, which suppresses the resonant energy distribution, thus reducing the bandwidth. Therefore, the frequency step of the band with a -3dB bandwidth less than the preset average is adjusted based on the ratio of the average bandwidth to the preset average, thereby reducing the impact of interference on the measurement results. The preset ratio R0 of the average bandwidth to the preset average is 0.88. The comparison process between the ratio R0 and the preset ratio R0 is as follows:

[0075] If the ratio R of the average bandwidth to the preset average bandwidth is less than or equal to the preset ratio R0, then the frequency step of the band with a -3dB bandwidth less than the preset average bandwidth is adjusted to 0.67 times the original frequency step, where the adjusted frequency step value is rounded up.

[0076] If the ratio R of the average bandwidth to the preset average bandwidth is greater than the preset ratio R0, then the frequency step of the band with a -3dB bandwidth less than the preset average bandwidth is adjusted to 0.83 times the original frequency step, where the adjusted frequency step value is rounded up.

[0077] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

[0078] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A test fixture for NMD flange connectors, characterized in that, include: The testing unit includes an NMD flange adapter, a vector network analyzer, and a fixing fixture, used to test the transmission signal of the NMD flange connector to be tested. The first end of the NMD flange adapter is fixed to the NMD flange interface of the product to be tested via a threaded connection. The inner conductor of the second end of the NMD flange adapter has a countersunk hole and the inner conductor of the periodically calibrated vector network analyzer is coaxially connected via an elastic pin. The outer conductor connected to the vector network analyzer is fixed to the flange of the NMD flange adapter. A calculation unit, connected to the detection unit, is used to receive detection data transmitted by the detection unit and to determine the reflection loss value based on the detection data. An analysis unit, connected to the calculation unit, is used to determine the test state based on the average value of the reflection loss value within a preset period, and to adjust the calibration period of the vector network analyzer and the reflection loss value based on the test state. The calculation unit further includes a calibration module, which is used to correct the reflection loss value based on the deviation value to determine the first reflection loss value; The calibration module is also used to correct the reflection loss value based on the first reflection loss value = reflection loss value + deviation value, wherein, In the formula, The current reflection loss value is the difference between the reflection loss value when the vector network analyzer was calibrated, and T is the time difference between the current value and the last time the vector network analyzer was calibrated. This refers to the adjusted calibration cycle for the vector network analyzer.

2. The test fixture for NMD flange connectors according to claim 1, characterized in that, The analysis unit is also used to obtain reflection loss values ​​at multiple moments in a preset period when the test state is determined to be unqualified. The analysis unit is also used to calculate the variance of the reflection loss value corresponding to multiple moments in the preset period, and, when the variance is less than the preset variance, to adjust the calibration period of the vector network analyzer based on the ratio of the variance to the preset variance. If the average value of the reflection loss is less than the preset average value, the test condition is determined to be unqualified.

3. The test fixture for NMD flange connectors according to claim 2, characterized in that, The analysis unit is also used to reduce the calibration cycle of the vector network analyzer based on the ratio of the variance to the preset variance, and the reduction in the calibration cycle is inversely proportional to the ratio.

4. The test fixture for NMD flange connectors according to claim 1, characterized in that, The analysis unit is also used to readjust the reflection loss value at least once if the test status is unqualified after correcting the reflection loss value, until the adjustment stops when the number of adjustments is less than the preset number and the test status is qualified or the number of adjustments is equal to the preset number. The analysis unit is also used to plot a historical period-average curve based on the average value of the reflection loss value over multiple historical periods when the test state is unqualified after the adjustment is stopped. The analysis unit is also used to adjust the axial mating distance of the connector based on the ratio of the integral to the preset integral when the integral of the curve is less than the preset integral.

5. The test fixture for NMD flange connectors according to claim 4, characterized in that, The analysis unit is also used to increase the axial mating distance of the connector based on the ratio of the integral to the preset integral, and the increase in the axial mating distance of the connector is inversely proportional to the ratio.

6. The test fixture for NMD flange connectors according to claim 5, characterized in that, The analysis unit is also used to plot a reflection loss value-frequency curve based on the frequencies corresponding to multiple reflection loss values ​​within a preset period when the test state is unqualified after adjusting the axial mating distance of the connector. The analysis unit is also used to calculate the average of the absolute values ​​of the slopes corresponding to multiple coordinate points of the curve, and to issue a calibration interface notification if the average value is less than a preset value.

7. The test fixture for NMD flange connectors according to claim 6, characterized in that, The analysis unit is also used to obtain the -3dB bandwidth of the peak of the preset frequency on the input reflection coefficient curve in the vector network analyzer when the energy storage state is unqualified after the calibration interface. The analysis unit is also used to adjust the frequency step of the band with a -3dB bandwidth that is less than the preset average value based on the ratio of the average value to the preset average value when the average value of the bandwidth is less than the preset average value.

8. The test fixture for NMD flange connectors according to claim 7, characterized in that, The analysis unit is also used to reduce the frequency step of the band with a bandwidth less than the preset average value by -3dB based on the ratio of the average value to the preset average value, and the reduction of the frequency step is inversely proportional to the ratio.

9. A test method, applied to the test fixture for NMD flange connectors as described in any one of claims 1-8, characterized in that, include: The transmission signal of the NMD flange connector to be tested is detected by a testing unit including an NMD flange adapter, a vector network analyzer, and a fixing fixture. The first end of the NMD flange adapter is fixed to the NMD flange interface of the product to be tested by a threaded connection. The inner conductor of the second end of the NMD flange adapter has a countersunk hole and the inner conductor of the periodically calibrated vector network analyzer is coaxially connected by an elastic pin. The outer conductor connected to the vector network analyzer is fixed on the flange of the NMD flange adapter. The computing unit connected to the detection unit receives the detection data transmitted by the detection unit and determines the reflection loss value based on the detection data. The analysis unit connected to the computing unit determines the test state based on the average value of the reflection loss value within a preset period, and adjusts the calibration period of the vector network analyzer and the reflection loss value based on the test state. The method further includes: The calibration module in the calculation unit corrects the reflection loss value based on the deviation value to determine the first reflection loss value; The process of correcting the reflection loss value based on the deviation value to determine the first reflection loss value includes: The reflection loss value is corrected based on the first reflection loss value = reflection loss value + deviation value, where, In the formula, The current reflection loss value is the difference between the reflection loss value when the vector network analyzer was calibrated, and T is the time difference between the current value and the last time the vector network analyzer was calibrated. This refers to the adjusted calibration cycle for the vector network analyzer.

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