CN110531170A - Shielded cable shielding attenuation measurement method - Google Patents

Shielded cable shielding attenuation measurement method Download PDF

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Publication number
CN110531170A
CN110531170A CN201910778948.2A CN201910778948A CN110531170A CN 110531170 A CN110531170 A CN 110531170A CN 201910778948 A CN201910778948 A CN 201910778948A CN 110531170 A CN110531170 A CN 110531170A
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CN
China
Prior art keywords
measurement
signal level
shielded cable
cable
tested
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
CN201910778948.2A
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Chinese (zh)
Inventor
李立嘉
罗亚锋
沈涛
崔强
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BEIJING ZHINAN TECHNOLOGY Co Ltd
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BEIJING ZHINAN TECHNOLOGY Co Ltd
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Priority to CN201910778948.2A priority Critical patent/CN110531170A/en
Publication of CN110531170A publication Critical patent/CN110531170A/en
Withdrawn legal-status Critical Current

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    • GPHYSICS
    • G01MEASURING; TESTING
    • G01RMEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R29/00Arrangements for measuring or indicating electric quantities not covered by groups G01R19/00 - G01R27/00
    • G01R29/08Measuring electromagnetic field characteristics
    • G01R29/0807Measuring electromagnetic field characteristics characterised by the application
    • G01R29/0814Field measurements related to measuring influence on or from apparatus, components or humans, e.g. in ESD, EMI, EMC, EMP testing, measuring radiation leakage; detecting presence of micro- or radiowave emitters; dosimetry; testing shielding; measurements related to lightning
    • G01R29/0835Testing shielding, e.g. for efficiency
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01RMEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/08Locating faults in cables, transmission lines, or networks

Abstract

The present invention provides a kind of shielded cable shielding attenuation measurement method, includes the following steps: that the Injection Signal level that unshielded position is extracted in same measuring signal access completes reference measure;The Injection Signal level for extracting tested shielded cable position completes shield EMC measurement;It is compared with the reference measurement values and shield EMC measurement value of identical parameter and unit, it is final to obtain tested shielded cable shielding attenuation value.

Description

Shielded cable shielding attenuation measurement method
Technical field
The present invention relates to a kind of method for measuring shielded cable shielding attenuation, especially one kind can be accurate, true, reliable The method for obtaining shielded cable shielding attenuation measurement result.
Background technique
Currently, having has two kinds of pincers method of absorbing clamp method and injection to the measurement of shielded cable shielding attenuation.Absorbing clamp method is A certain signal level is directly injected into tested shielded cable by signal generator, with measurement receiving device measurement card in quilt The signal level that the absorbing clamp surveyed outside shield layer of shielded cable obtains obtains the tested shielding electricity by comparing two signal levels The shielding attenuation value of cable;Injection pincers method is by the injection pincers being stuck in outside tested shield layer of shielded cable that a certain signal level is straight It connects and is injected into tested shielded cable, the signal level in tested shielded cable is measured with measurement receiving device, by comparing two Signal level obtains the shielding attenuation value of the tested shielded cable.
Main problem existing for both methods is, when the coaxial cable of tested shielded cable non-50 omega transfer impedance, Because being difficult to obtain the actual transfer impedance of tested cable, it can not accomplish that the measuring device of tested cable and 50 Ω characteristic impedances is realized The exact matching of impedance, therefore measure and receive in the output signal level value and injection pincers method that signal generator indicates in absorbing clamp method The signal level measuring value that equipment provides cannot be guaranteed its authenticity, then the shielding attenuation of the tested shielded cable finally obtained Measurement result can not really reflect the real standard of tested shielded cable shielding attenuation.
Summary of the invention
The purpose of the present invention is to provide a kind of shielded cable shielding attenuation measurement method, solve to hinder in tested shielded cable In the case where anti-difference, existing measurement method is made because being tested the measuring device mismatch of cable transmission impedance and 50 Ω characteristic impedances At measurement error, to guarantee the true and reliable of measurement result.
To solve the above problems, the embodiment of the present invention provides a kind of shielded cable shielding attenuation measurement method, including as follows Step:
The Injection Signal level that unshielded position is extracted in same measuring signal access completes reference measure;
The Injection Signal level for extracting tested shielded cable position completes shield EMC measurement;
It is compared with the reference measurement values and shield EMC measurement value of identical parameter and unit, it is final to obtain tested shielded cable Shielding attenuation value.
Further, the reference measure and the shield EMC measurement are completed by measuring system, and the measuring system includes Signal level generates and injection subsystem and signal level measuring subsystem;
The signal level is generated with injection subsystem by signal generator, measurement cable, measurement servicing unit, tested screen Cover cable and terminal load composition;Wherein the signal generator is used to pass through signal level for measurement access;The measurement is auxiliary It helps device for realizing the connection perforation of measurement cable and tested shielded cable, unmask state in measuring signal access is provided Measurement position point;
The signal level measuring subsystem is by first line current draw equipment, the second line current extract equipment and survey Measure receiving device composition;The first line current draw equipment and the second line current extract equipment are respectively used to extract measurement The signal level of unshielded position and tested shielded cable position in signal path;The measurement receiving device is used for line electricity The signal level that stream extract equipment is extracted measures, and provides reference measurement values and shield EMC measurement value.
Further, the method specifically comprises the following steps:
S1: signal generator, measurement cable, measurement servicing unit, tested shielded cable and terminal load are sequentially connected; First line current draw equipment is arranged in measurement servicing unit;By the setting of the second line current extract equipment in tested screen It covers on cable;
S2: signal generator provides measured signal level, so that measured signal level is auxiliary through measurement cable and current measurement Device is helped to be injected into tested shielded cable;
S3: first line current draw equipment is connected with measurement receiving device, measures unmask state in access Signal level measuring obtains reference measurement values I0
S4: the second line current extract equipment is connected with measurement receiving device, carries out the survey of signal level after shielding attenuation Amount, obtains shield EMC measurement value I1。。
Further, the method also includes: use reference measurement values I0(dB) shield EMC measurement value I is subtracted1(dB) it is shielded Pad value SA (dB).
Further, the first line current draw equipment and the second line current extract equipment are that current measurement is visited Head.
Compared with prior art, the present invention uses identical measuring device, extracts in same measuring signal access without screen The Injection Signal level for covering position completes reference measure, and the Injection Signal level for extracting tested shielded cable position is completed shielding and surveyed Amount, and be compared with the reference measurement values and shield EMC measurement value of identical parameter and unit, it is final to obtain tested shielded cable screen Cover pad value.This method be suitable for any transfer impedance shielded cable shielding attenuation measurement, be not required to consider shielded cable with Resistance matching problem between measuring device obtains true and reliable measurement result.
Detailed description of the invention
Fig. 1 for a kind of shielded cable shielding attenuation measurement method provided in an embodiment of the present invention showing using measuring system It is intended to.
In figure: the first current measurement probe of 1-;The second current measurement probe of 2-;3- signal generator;The load of 4- terminal;5- Measure receiving device;6- measurement servicing unit;7- measures cable;8- is tested shielded cable.
Specific embodiment
Several illustrative embodiments shown in below with reference to the accompanying drawings describe the principle and spirit of the invention.It should Understand, describe these embodiments just for the sake of make those skilled in the art can better understand that in turn realize the present invention, And this scope of the present invention is not limited in any way.
A kind of shielded cable shielding attenuation measurement method provided in an embodiment of the present invention, alternatively referred to as equivalent comparison method, It is a kind of using identical measuring device, the Injection Signal level that unshielded position is extracted in same measuring signal access is completed Reference measure, the Injection Signal level for extracting tested shielded cable position complete shield EMC measurement, and with identical parameter and unit Reference measurement values and shield EMC measurement value are compared, the final measurement method for obtaining tested shielded cable shielding attenuation value.
In the method, entire measuring system include two relatively independent subsystems: one be by signal generator 3, Measure " signal level generation and the injection subsystem of cable 7,4 composition of measurement servicing unit 6, tested shielded cable 8 and terminal load System ", the other is being connect by two current measurement probes (the first current measurement probe 1 and the second current measurement probe 2) and measurement " the signal level measuring subsystem " that receiving unit 5 forms.Although the signal generator of 50 Ω characteristic impedances may be with tested shielding The transfer impedance of cable is inconsistent, but signal level measuring when measuring signal access unmask state is shielded with through shielded cable Signal level measuring after decaying is realized by " signal level measuring subsystem ", in measurement process, is extracted from signal level It is transferred to signal level measuring to complete under 50 Ω characteristic impedances, i.e. the impedance with " signal level generates and injection subsystem " It is uncorrelated whether matching, so, impedance mismatch factor present in " signal level generates and injection subsystem " will not be to survey Amount result affects, to ensure that the true and reliable of measurement result.
In the following, first being explained to the technical term in the embodiment of the present invention:
Reference measure: being with line current extract equipment (specifically can be current measurement probe, also referred to as electric current clamp etc.) The signal level value that unmask state flows through signal path, i.e. reference measurement values are measured on current measurement auxiliary device.With reference to The parameter that measured value provides can be electric current, voltage or power etc..
Shield EMC measurement: being with line current extract equipment (specifically can be current measurement probe, also referred to as electric current clamp etc.) The signal level value for having masked state to flow through signal path, i.e. shield EMC measurement value are measured on the position of shielded cable.Shielding is surveyed The parameter and unit that magnitude provides are identical as reference measurement values.
Above-mentioned measurement method provided in an embodiment of the present invention, is completed using measuring system, which mainly includes such as Lower equipment:
Signal generator 3: pass through signal level for measurement access.
Current measurement probe: it 2, is respectively used to extract unshielded (reference measure) position in measuring signal access and is tested The signal level of shielded cable (shield EMC measurement) position.Wherein it is known as the survey of the first electric current for the current measurement probe of reference measure Amount probe 1, the current measurement probe for carrying out shield EMC measurement is known as the second current measurement probe 2.
Measurement receiving device 5: for measuring to the signal level that measuring probe extracts, reference measurement values and screen are provided Cover measured value.Measuring receiving device 5 specifically can be using measurement receiving instrument, such as spectrum analyzer.
Measurement servicing unit 6: for realizing the connection perforation of measurement cable 7 and tested shielded cable 8, measuring signal is provided The measurement position point of unmask state in access.Measurement servicing unit can use cable connector.
Specifically, it is based on the above measuring system, measurement method includes measuring process below
S1: instrumentation plan as shown in Figure 1 measures the connection of equipment and tested shielded cable.By signal generator 3, cable 7, measurement servicing unit 6, tested shielded cable 8 and terminal load 4 is measured to be sequentially connected according to above-mentioned put in order Together.First measuring probe 1 is stuck in measurement servicing unit 6;Second measuring probe 2 is stuck on tested shielded cable 8.
S2: the measured signal level that signal generator 3 provides is injected into tested through measurement cable 7 and measurement servicing unit 6 In shielded cable 8.
S3: access is measured with first measuring probe 1 of measurement 5 connection card of receiving device in measurement servicing unit 6 The signal level measuring of middle unmask state obtains reference measurement values I0
S4: shielding attenuation is carried out with second measuring probe 2 of measurement 5 connection card of receiving device on tested shielded cable 8 The measurement of signal level afterwards obtains shield EMC measurement value I1
Finally, the calculating of shielding attenuation is carried out,
Formula (1) is shown in the calculating of tested shielded cable shielding attenuation.
SA=I0- I1……………………………………(1)
In formula:
SA --- shielding attenuation value, unit are decibel (dB);
I0--- reference measurement values, unit are decibel (dB);
I1--- shield EMC measurement value, unit are decibel (dB).
This method is suitable for the measurement of the shielded cable shielding attenuation of any transfer impedance, is not required to consider shielded cable and survey Measure the resistance matching problem between equipment.
In addition, this method is not only applicable in the measurement of single shielded cable shielding attenuation, it is also applied for shielded multiconductor cable screen Cover the measurement of decaying.
Specific case used herein elaborates inventive concept, the explanation of above example is only intended to Help understands core of the invention thought.It should be pointed out that for those skilled in the art, not departing from this Under the premise of inventive concept, any obvious modification, equivalent replacement or the other improvements made should be included in the present invention Protection scope within.

Claims (5)

1. a kind of shielded cable shielding attenuation measurement method, which comprises the steps of:
The Injection Signal level that unshielded position is extracted in same measuring signal access completes reference measure;
The Injection Signal level for extracting tested shielded cable position completes shield EMC measurement;
It is compared with the reference measurement values and shield EMC measurement value of identical parameter and unit, it is final to obtain tested shielded cable shielding Pad value.
2. the method according to claim 1, wherein the reference measure and the shield EMC measurement pass through measurement system System is completed, and the measuring system includes that signal level generates and injection subsystem and signal level measuring subsystem;
The signal level is generated with injection subsystem by signal generator, measurement cable, measurement servicing unit, tested shielding electricity Cable and terminal load composition;Wherein the signal generator is used to pass through signal level for measurement access;The measurement auxiliary dress The connection perforation for realizing measurement cable and tested shielded cable is set, the measurement of unmask state in measuring signal access is provided Location point;
The signal level measuring subsystem is connect by first line current draw equipment, the second line current extract equipment and measurement Receiving unit composition;The first line current draw equipment and the second line current extract equipment are respectively used to extract measuring signal The signal level of unshielded position and tested shielded cable position in access;The measurement receiving device is for mentioning line current The signal level for taking equipment to extract measures, and provides reference measurement values and shield EMC measurement value.
3. according to the method described in claim 2, it is characterized in that, the method specifically comprises the following steps:
S1: signal generator, measurement cable, measurement servicing unit, tested shielded cable and terminal load are sequentially connected;By One line current extract equipment is arranged in measurement servicing unit;By the setting of the second line current extract equipment in tested shielding electricity On cable;
S2: signal generator provides measured signal level, so that measured signal level is through measurement cable and current measurement auxiliary dress It sets and is injected into tested shielded cable;
S3: first line current draw equipment is connected with measurement receiving device, measures the signal of unmask state in access Level measurement obtains reference measurement values I0
S4: the second line current extract equipment is connected with measurement receiving device, the measurement of signal level after shielding attenuation is carried out, obtains To shield EMC measurement value I1。。
4. according to the method described in claim 3, it is characterized in that, the method also includes: use reference measurement values I0(dB) it subtracts Shield EMC measurement value I1(dB) shielding attenuation value SA (dB) is obtained.
5. method according to claim 1 to 4, which is characterized in that the first line current draw equipment and second Line current extract equipment is current measurement probe.
CN201910778948.2A 2019-08-22 2019-08-22 Shielded cable shielding attenuation measurement method Withdrawn CN110531170A (en)

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Application Number Priority Date Filing Date Title
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114264851A (en) * 2021-12-22 2022-04-01 北京大泽科技有限公司 Electromagnetic shielding attenuation measurement method for shielded cable

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101191806A (en) * 2006-11-29 2008-06-04 比亚迪股份有限公司 Apparatus and method for testing automobile electromagnetic sensitivity
CN101871975A (en) * 2010-06-21 2010-10-27 中国人民解放军理工大学 System and method for testing cable transfer impedance time domain
US20110219147A1 (en) * 2010-03-02 2011-09-08 Wael William Diab Method And System For Determining Characteristics Of An Attached Ethernet Connector And/Or Cable
CN103543342A (en) * 2012-07-10 2014-01-29 中国兵器工业新技术推广研究所 Method and system for testing shielding performance of cable
CN104215885A (en) * 2013-06-05 2014-12-17 石从元 Method and device for detecting whether insulation and shielding performances of in-operation power cable are lowered or not
CN208109955U (en) * 2018-03-28 2018-11-16 上海乐来汽车分析测试有限公司 A kind of shielding properties test macro of Belt connector harness
CN109375020A (en) * 2018-11-09 2019-02-22 中国汽车技术研究中心有限公司 A kind of test device and method of new-energy automobile high-tension cable shield effectiveness
CN109709435A (en) * 2019-03-07 2019-05-03 重庆大学 A kind of measurement method of electric automobile high-voltage shielded cable shield effectiveness

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101191806A (en) * 2006-11-29 2008-06-04 比亚迪股份有限公司 Apparatus and method for testing automobile electromagnetic sensitivity
US20110219147A1 (en) * 2010-03-02 2011-09-08 Wael William Diab Method And System For Determining Characteristics Of An Attached Ethernet Connector And/Or Cable
CN101871975A (en) * 2010-06-21 2010-10-27 中国人民解放军理工大学 System and method for testing cable transfer impedance time domain
CN103543342A (en) * 2012-07-10 2014-01-29 中国兵器工业新技术推广研究所 Method and system for testing shielding performance of cable
CN104215885A (en) * 2013-06-05 2014-12-17 石从元 Method and device for detecting whether insulation and shielding performances of in-operation power cable are lowered or not
CN208109955U (en) * 2018-03-28 2018-11-16 上海乐来汽车分析测试有限公司 A kind of shielding properties test macro of Belt connector harness
CN109375020A (en) * 2018-11-09 2019-02-22 中国汽车技术研究中心有限公司 A kind of test device and method of new-energy automobile high-tension cable shield effectiveness
CN109709435A (en) * 2019-03-07 2019-05-03 重庆大学 A kind of measurement method of electric automobile high-voltage shielded cable shield effectiveness

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114264851A (en) * 2021-12-22 2022-04-01 北京大泽科技有限公司 Electromagnetic shielding attenuation measurement method for shielded cable
CN114264851B (en) * 2021-12-22 2023-08-04 北京大泽科技有限公司 Electromagnetic shielding attenuation measurement method for shielded cable

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