CN117607559A - System and method for measuring attenuation of impedance asymmetric attenuator - Google Patents
System and method for measuring attenuation of impedance asymmetric attenuator Download PDFInfo
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- CN117607559A CN117607559A CN202311466725.5A CN202311466725A CN117607559A CN 117607559 A CN117607559 A CN 117607559A CN 202311466725 A CN202311466725 A CN 202311466725A CN 117607559 A CN117607559 A CN 117607559A
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- 238000005259 measurement Methods 0.000 claims abstract description 36
- 230000005540 biological transmission Effects 0.000 claims description 14
- 238000012360 testing method Methods 0.000 claims description 13
- 230000004044 response Effects 0.000 claims description 9
- 238000007796 conventional method Methods 0.000 abstract description 2
- 238000013016 damping Methods 0.000 description 10
- 230000001052 transient effect Effects 0.000 description 10
- 238000010586 diagram Methods 0.000 description 7
- 230000008569 process Effects 0.000 description 6
- 230000000694 effects Effects 0.000 description 3
- 238000012986 modification Methods 0.000 description 2
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- 230000009286 beneficial effect Effects 0.000 description 1
- 230000006870 function Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- 238000003012 network analysis Methods 0.000 description 1
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- 239000013307 optical fiber Substances 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R29/00—Arrangements for measuring or indicating electric quantities not covered by groups G01R19/00 - G01R27/00
- G01R29/16—Measuring asymmetry of polyphase networks
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R1/00—Details of instruments or arrangements of the types included in groups G01R5/00 - G01R13/00 and G01R31/00
- G01R1/20—Modifications of basic electric elements for use in electric measuring instruments; Structural combinations of such elements with such instruments
- G01R1/203—Resistors used for electric measuring, e.g. decade resistors standards, resistors for comparators, series resistors, shunts
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Abstract
The application discloses a system and a method for measuring attenuation of an impedance asymmetric attenuator, which solve the problem that a network analyzer method is not suitable for measuring the attenuation of the asymmetric attenuator. A measuring system for attenuation of an impedance asymmetric attenuator comprises a network analyzer and a fixed impedance unit. The fixed impedance unit is used for providing a fixed impedance, and the fixed impedance is connected with the impedance asymmetric attenuator to be measured in parallel and then connected to two ends of the network analyzer. The input end impedance of the impedance asymmetric attenuator is parallel to the fixed impedance and then is equal to the source impedance of the network analyzer. The method and the device effectively avoid mismatched measurement errors caused by impedance mismatch; compared with the conventional method, the method has better adaptability and accuracy for measuring the impedance asymmetric attenuator.
Description
Technical Field
The application relates to the technical field of radio metering, in particular to a system and a method for measuring attenuation of an impedance asymmetric attenuator.
Background
Attenuation is one of the basic parameters of radio metering, and characterizes the degree of attenuation of the amplitude of radio signals in the transmission process, and is the transmission characteristic of various transmission lines, electronic components, electronic equipment and systems, and in particular, attenuation measurement has important significance in military metering and military metering.
The types of attenuators are various, and can be classified into fixed attenuators and variable attenuators according to the variable conditions of attenuation; according to different output forms, the optical fiber can be divided into a waveguide attenuator and a coaxial attenuator; according to different principles, the impedance asymmetric attenuator can be divided into a resistive attenuator, a rotary attenuator, a cut-off attenuator, an absorption attenuator and the like, and belongs to one of the resistive attenuators.
At present, the method for measuring the attenuation of the resistance type attenuator adopts a network analyzer method. In order to realize the measurement of the attenuation, a network analyzer is adopted for direct measurement, and the scanning type, frequency, scanning point number, average frequency and intermediate frequency bandwidth of the network analyzer are set according to the requirement of the measured attenuator during measurement; then, performing full two-port calibration or connecting two test ports of the network analyzer to perform transmission frequency response calibration; setting measurement parameters; and finally, connecting the measured attenuator to the position between the two end cables of the network analyzer, and recording the reading of the network analyzer at the moment, namely the attenuation of the resistive attenuator.
However, the measurement process of the network analyzer method is performed under the condition of ideal impedance matching, that is, under the condition that two port loads of the network analyzer are completely matched, and the measurement of the attenuation amount of the impedance asymmetric attenuator is inaccurate due to mismatch errors caused by incomplete load matching, especially for the impedance asymmetric attenuator with input impedance of 600 Ω and output impedance of 50 Ω (which is a common impedance asymmetric attenuator in electromagnetic compatibility test). There is a need for an apparatus and method that can reduce mismatch effects and enable measurement of the attenuation of an impedance asymmetric attenuator.
Disclosure of Invention
The embodiment of the application provides a system and a method for measuring the attenuation of an impedance asymmetric attenuator, which solve the problem that a network analyzer method is not suitable for measuring the attenuation of the asymmetric attenuator.
In a first aspect, an embodiment of the present application provides a system for measuring attenuation of an impedance asymmetric attenuator, including a network analyzer and a fixed impedance unit. The fixed impedance unit is used for providing a fixed impedance, and the fixed impedance is connected with the impedance asymmetric attenuator to be measured in parallel and then connected to two ends of the network analyzer. The input end impedance of the impedance asymmetric attenuator is parallel to the fixed impedance and then is equal to the source impedance of the network analyzer.
In one embodiment, the fixed impedance unit is a pass-through impedance converter. The pass-through impedance converter includes a resistor, a shield box, and a radio frequency port. The resistor is sealed in a shielding box, and radio frequency ports are arranged at two ends of the resistor.
In one embodiment, the fixed impedance unit further comprises an adjustment device. The adjusting device is used for adjusting the impedance of the fixed impedance unit.
In one embodiment, the network analyzer is selected from model E5061B.
In a second aspect, an embodiment of the present application further provides a method for measuring an attenuation amount of an impedance asymmetric attenuator, where the system for measuring an attenuation amount of an impedance asymmetric attenuator according to any one of the embodiments of the first aspect includes:
installing an impedance asymmetric attenuator to be measured on the measurement system;
adjusting the impedance value of the fixed impedance unit;
and starting the network analyzer to obtain a measurement result.
In one embodiment, determining the impedance value of the fixed impedance unit specifically includes the steps of:
determining a network analyzer source impedance;
determining the input end impedance of the impedance asymmetric attenuator to be measured;
and calculating the impedance value of the fixed impedance unit according to the source impedance of the network analyzer and the impedance of the input end.
In one embodiment, before the impedance asymmetry attenuator to be measured is connected to the measurement system, the method further comprises the steps of:
and starting up the network analyzer to preheat, so that the temperature and devices in the machine are stable.
In one embodiment, after the impedance asymmetry attenuator to be measured is connected to the measurement system, the method further comprises the steps of:
setting parameters of a network analyzer;
performing transmission frequency response calibration on two test ports of the network analyzer;
and setting measurement parameters.
In one embodiment, the parameters of the network analyzer include scan type, frequency, number of scans, average number of times, intermediate frequency bandwidth.
The above-mentioned at least one technical scheme that this application embodiment adopted can reach following beneficial effect:
the measuring method adopted by the application can realize the measurement of the attenuation of the impedance asymmetric attenuator. The measuring device is composed of the through type impedance converter, so that the measuring requirement of impedance mismatch of the impedance asymmetric attenuator is met; the measurement error caused by mismatch due to impedance mismatch is effectively avoided; compared with the conventional method, the method has better adaptability and accuracy for measuring the impedance asymmetric attenuator.
Drawings
The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiments of the application and together with the description serve to explain the application and do not constitute an undue limitation to the application. In the drawings:
FIG. 1 is a block diagram of a method for measuring open circuit voltage of a damped sinusoidal transient signal generator using an impedance asymmetric attenuator;
FIG. 2 is a block diagram of a device of a prior art network analyzer method;
FIG. 3 is a diagram illustrating a system for measuring attenuation of an impedance asymmetric attenuator according to an embodiment of the present application;
FIG. 4 is a specific block diagram of a measurement system for attenuation of an impedance asymmetric attenuator according to an embodiment of the present application;
FIG. 5 is a flowchart of a method for measuring attenuation of an impedance asymmetric attenuator according to an embodiment of the present application;
fig. 6 is a flowchart of another method for measuring attenuation of an impedance asymmetric attenuator according to an embodiment of the present application.
Detailed Description
For the purposes, technical solutions and advantages of the present application, the technical solutions of the present application will be clearly and completely described below with reference to specific embodiments of the present application and corresponding drawings. It will be apparent that the described embodiments are only some, but not all, of the embodiments of the present application. All other embodiments, which can be made by one of ordinary skill in the art without undue burden from the present disclosure, are within the scope of the present disclosure.
As shown in fig. 1, an impedance asymmetric attenuator is used for measuring the open-circuit voltage of a damping sinusoidal transient signal generator of key equipment in a CS116 test project in a GJB151B, in the measuring process, the impedance asymmetric attenuator with input impedance of 600 Ω and output impedance of 50 Ω is connected to the output end of the damping sinusoidal transient signal generator, then the open-circuit voltage of the damping sinusoidal transient signal generator is measured by an oscilloscope, and in the whole measuring process, the impedance asymmetric attenuator provides attenuation of 40 dB.
The impedance asymmetric attenuator is used for damping the damping sinusoidal transient pulse peak value output by the damping sinusoidal transient signal generator, and because the amplitude output by the damping sinusoidal transient signal generator reaches 2000V, in order to measure the voltage pulse output by the damping sinusoidal transient signal generator in an open circuit state, the impedance asymmetric attenuator is used as an attenuation matching network, on one hand, the 600 omega input end can simulate the open circuit state of the damping sinusoidal transient pulse generator, and on the other hand, the 50 omega output end can be matched with the 50 omega input impedance of an oscilloscope, so that the open circuit state of the damping sinusoidal transient pulse generator can be simulated, and the effects of attenuation and impedance matching of high-voltage pulses are also achieved.
As shown in fig. 2, the existing method for measuring the attenuation of the resistive attenuator is mainly a network analyzer method, and the measuring process of the method is performed under the condition of ideal impedance matching, namely, under the condition that two port loads of the network analyzer are completely matched, the measurement of the attenuation of the resistive attenuator is completed in a 50Ω transmission system, and when the impedance asymmetric attenuator, especially the input impedance and the output impedance asymmetric attenuator, is measured according to the method, mismatch errors are generated due to incomplete load matching, so that inaccurate measurement of the attenuation of the impedance asymmetric attenuator can be caused.
The following describes in detail the technical solutions provided by the embodiments of the present application with reference to the accompanying drawings.
Fig. 3 is a block diagram of a measurement system for attenuation of an impedance asymmetric attenuator according to an embodiment of the present application. The application embodiment provides a measuring system for attenuation of an impedance asymmetric attenuator, which comprises a network analyzer 1 and a fixed impedance unit 2.
The fixed impedance unit is used for providing a fixed impedance, and the fixed impedance is connected with the impedance asymmetric attenuator to be measured in parallel and then connected to two ends of the network analyzer.
It should be noted that, in fig. 3, the fixed impedance unit and the impedance asymmetric attenuator to be measured are in a series connection relationship, but in the internal circuit, the fixed impedance provided by the fixed impedance unit and the asymmetric attenuator are in a parallel connection relationship.
In one embodiment, the fixed impedance unit is a pass-through impedance converter. The pass-through impedance converter includes a resistor, a shield box, and a radio frequency port. The resistor is sealed in a shielding box, and radio frequency ports are arranged at two ends of the resistor.
Specifically, the impedance asymmetric attenuator to be measured is connected with the through converter and then connected between the cables at two ends of the network analyzer.
Fig. 4 is a specific structural diagram of a measurement system for attenuation of an impedance asymmetric attenuator according to an embodiment of the present application.
As shown in fig. 4, in the case of unmatched measured impedance, a through impedance converter is designed, and after the converter is connected with the input end of the impedance asymmetric attenuator, impedance matching of a measurement system can be realized, maximum power transmission is obtained, and influence of mismatch errors is reduced.
For example, according to the principle of impedance matching of the system, from a 600 Ω port to a pass-through impedance converter, 600 Ω and the pass-through impedance converter are connected in parallel and then equal to 50 Ω; i.e. the source impedance R of the network analyzer 2 =50Ω, calculating the impedance R of the pass impedance converter according to the circuit parallel equation 1 。
And (3) according to the resistance value of the fixed impedance calculated in the formula (1), selecting a proper resistor to seal the whole circuit in a shielding box, and installing corresponding radio frequency ports at two ends to manufacture a practical through impedance converter.
The input end impedance of the impedance asymmetric attenuator is parallel to the fixed impedance and then is equal to the source impedance of the network analyzer.
In one embodiment, the fixed impedance unit further comprises an adjustment device. The adjusting device is used for adjusting the impedance of the fixed impedance unit and is equal to the source impedance of the network analyzer after being matched with the input end impedance of the impedance asymmetric attenuator.
Since the fixed impedance unit needs to be changed according to the impedance of the input end of the impedance asymmetric attenuator to be measured, the fixed impedance unit preferably further comprises an adjusting device, and the size of the fixed impedance is changed through the adjusting device.
It should be noted that, the fixed impedance and the fixed impedance unit described in the present application refer to providing a fixed impedance during the measurement process, and not only providing a fixed impedance.
For example, according to the measuring system of the application, the attenuation of an impedance asymmetric attenuator with the model number 9454-1 is measured, a network analyzer and a through impedance converter are connected according to the diagram shown in fig. 3 to form the measuring system, the model number E5061B of the network analyzer is selected, and the through impedance converter is selected from grinding equipment.
The device under test: impedance asymmetric attenuator
Model: 9454-1
Frequency range: 100 Hz-1 GHz
The attenuation technical index is as follows: 40dB (maximum allowable error: + -1.5 dB (frequency range: 100 Hz-700 MHz), 1dB to +3dB (frequency range: 700 MHz-1 GHz))
Input impedance: 600 omega
Output impedance: 50 omega
Measuring the index: attenuation amount
The measurement was performed according to the steps of the measurement method of the present invention, and the measurement data are shown in table 1.
Table 1 model 9454-1 attenuation amount measurement data table for impedance asymmetric attenuator
From the data in table 1, the measured value of the attenuation of the impedance asymmetric attenuator of the model meets the technical index requirement of the maximum allowable error in the whole frequency range, and further proves that the attenuation of the impedance asymmetric attenuator of the model meets the theoretical requirement well, and the rationality and accuracy of the application are verified.
Fig. 5 is a flowchart of a method for measuring attenuation of an impedance asymmetric attenuator according to an embodiment of the present application. An embodiment of the present application further provides a method for measuring an attenuation amount of an impedance asymmetric attenuator, where the system for measuring an attenuation amount of an impedance asymmetric attenuator according to any one of the embodiments of the first aspect includes the steps of:
step 110, installing an impedance asymmetric attenuator to be measured on the measurement system;
step 120, adjusting the impedance value of the fixed impedance unit;
and 130, starting a network analyzer to obtain a measurement result.
And after the network analyzer finishes scanning measurement, recording the reading of the network analyzer at the moment, namely the attenuation of the impedance asymmetric attenuator.
Fig. 6 is a flowchart of another method for measuring attenuation of an impedance asymmetric attenuator according to an embodiment of the present application.
In one of the embodiments of the present invention,
step 110, installing an impedance asymmetric attenuator to be measured on the measurement system;
step 120, adjusting the impedance value of the fixed impedance unit;
the method for determining the impedance value of the fixed impedance unit specifically comprises the following steps:
step 1201, determining the source impedance of a network analyzer;
step 1202, determining the input end impedance of an impedance asymmetric attenuator to be measured;
step 1203, calculating an impedance value of the fixed impedance unit according to the network analysis source impedance and the input end impedance.
And 130, starting a network analyzer to obtain a measurement result.
In one embodiment, before the impedance asymmetry attenuator to be measured is connected to the measurement system, the method further comprises the steps of:
and starting up the network analyzer to preheat, so that the temperature and devices in the machine are stable.
In one embodiment, after the impedance asymmetry attenuator to be measured is connected to the measurement system, the method further comprises the steps of:
setting parameters of a network analyzer;
performing transmission frequency response calibration on two test ports of the network analyzer;
the effect of the transmission frequency response calibration is equivalent to the normalization test process, namely, the test result is firstly stored in a memory of the network analyzer to obtain a reference line, and then the test result of the measured impedance asymmetric attenuator is compared with the reference line, so that the attenuation of the impedance asymmetric attenuator can be obtained.
Setting the scanning type, frequency, scanning point number, average frequency and intermediate frequency bandwidth of the network analyzer; then, performing full two-port calibration or connecting two test ports of the network analyzer to perform transmission frequency response calibration; setting a measurement parameter as S21; and finally, connecting the measured impedance asymmetric attenuator between the cables at two ends of the network analyzer, and recording the reading of the network analyzer at the moment, namely the attenuation of the impedance asymmetric attenuator.
And carrying out transmission frequency response calibration on the network analyzer test port 1 and the network analyzer test port 2.
For example, in a specific implementation mode, a frequency range is set, two ports of the network analyzer are respectively connected with cables, then two sections of cables are connected through a through connector, and the calibration of transmission frequency response is realized through a transmission frequency response calibration menu function of the network analyzer.
The foregoing is merely exemplary of the present application and is not intended to limit the present application. Various modifications and changes may be made to the present application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc. which are within the spirit and principles of the present application are intended to be included within the scope of the claims of the present application.
Claims (9)
1. The system for measuring the attenuation of the impedance asymmetric attenuator is characterized by comprising a network analyzer and a fixed impedance unit;
the fixed impedance unit is used for providing a fixed impedance, and the fixed impedance is connected with the impedance asymmetric attenuator to be tested in parallel and then connected to two ends of the network analyzer;
the input end impedance of the impedance asymmetric attenuator is parallel to the fixed impedance and then is equal to the source impedance of the network analyzer.
2. The system for measuring the attenuation of an impedance asymmetric attenuator according to claim 1, wherein said fixed impedance unit is a pass-through impedance converter;
the pass-through impedance converter comprises a resistor, a shielding box and a radio frequency port;
the resistor is sealed in a shielding box, and radio frequency ports are arranged at two ends of the resistor.
3. The system for measuring the attenuation of an impedance asymmetric attenuator according to claim 1, wherein said fixed impedance unit further comprises an adjusting means;
the adjusting device is used for adjusting the impedance of the fixed impedance unit.
4. The system for measuring the attenuation of an impedance asymmetric attenuator according to claim 1, wherein said network analyzer is selected from the group consisting of model E5061B.
5. A method for measuring the attenuation of an impedance asymmetric attenuator according to any one of claims 1 to 4, comprising the steps of:
installing an impedance asymmetric attenuator to be measured on the measurement system;
adjusting the impedance value of the fixed impedance unit;
and starting the network analyzer to obtain a measurement result.
6. The method for measuring attenuation of an impedance asymmetric attenuator according to claim 5, wherein determining the impedance value of the fixed impedance unit comprises the steps of:
determining a source impedance of the network analyzer;
determining the input end impedance of the impedance asymmetric attenuator to be measured;
and calculating the impedance value of the fixed impedance unit according to the source impedance and the input end impedance.
7. The method for measuring the attenuation of an impedance asymmetric attenuator according to claim 5, further comprising the steps of, before said impedance asymmetric attenuator to be measured is connected to said measuring system:
and starting up the network analyzer to preheat, so that the temperature and devices in the machine are stable.
8. The method for measuring attenuation of an impedance asymmetric attenuator according to claim 5, further comprising the steps of, after said impedance asymmetric attenuator to be measured is connected to said measuring system:
setting parameters of a network analyzer;
and carrying out transmission frequency response calibration on the two test ports of the network analyzer.
9. The method of measuring attenuation of an impedance asymmetric attenuator according to claim 5, wherein the parameters of said network analyzer include scan type, frequency, number of scan points, average number of times, intermediate frequency bandwidth.
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| CN202311466725.5A CN117607559A (en) | 2023-11-06 | 2023-11-06 | System and method for measuring attenuation of impedance asymmetric attenuator |
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| CN202311466725.5A CN117607559A (en) | 2023-11-06 | 2023-11-06 | System and method for measuring attenuation of impedance asymmetric attenuator |
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