CN101685125B - Method of testing isolation between wire cables by adopting harmonic waves - Google Patents
Method of testing isolation between wire cables by adopting harmonic waves Download PDFInfo
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- CN101685125B CN101685125B CN 200810215272 CN200810215272A CN101685125B CN 101685125 B CN101685125 B CN 101685125B CN 200810215272 CN200810215272 CN 200810215272 CN 200810215272 A CN200810215272 A CN 200810215272A CN 101685125 B CN101685125 B CN 101685125B
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Abstract
The invention relates to the field of electromagnetic compatibility detection, and provides a method of testing isolation between wire cables by adopting harmonic waves. The method comprises the following steps: 1. according to the requirements of a testing frequency range fa-fb and a frequency separation accuracy fi, determining the fundamental frequency of the harmonic waves and the harmonic order; 2. generating harmonic signals and injecting the harmonic signals into interfering wire cables; 3. testing the intensity of each order of the harmonic waves of the interfering wire cables and theinterfered wire cables; and 4. computing the isolation between the wire cables on each harmonic frequency point. The method can simultaneously complete the detection of the electromagnetic compatibility isolation on a wider bandwidth by injecting a group of harmonic waves once, thereby greatly improving the testing efficiency.
Description
Technical field
The present invention relates to electromagnetic compatibility detection technique field, relate in particular to the detection method field of isolation between cable.
Background technology
Along with the complicated and diversification of electronic system use cable, coupled relation becomes increasingly complex between cable, and it is increasing that electromagnetic compatibility is analyzed difficulty.Especially along with the frequency of transmitting signal in the cable improves constantly, occupied bandwidth is constantly expanded, other responsive cables of radiation interference that cable produces with antenna form have become the important source of electromagnetic compatibility problem.
During the response of the electromagnetic coupled between test cable at present, adopt by the Frequency point method of testing: under the condition of the demand that satisfies test frequency scope and frequency interval, frequency that at every turn can only the signalization source, after single-frequency signals injected cable, tested the electromagnetic coupled response of this frequency at tested cut cable by receiver or frequency spectrograph.Owing to once can only test the frequency response of a frequency, when testing the broadband response between a cable, need carry out single frequency point scanning to whole frequency band, the time, long speed was slow.A large amount of cables that in some complicated electronic systems, distributed, the coupling test job amount between cable is very big, and the time of adopting existing conventional test methodologies to consume makes us being difficult to bear.
Why electromagnetic coupled test at present or electromagnetic susceptibility (EMS) test all are to adopt single-frequency signals, be in order to prevent that multifrequency signal from producing non-linear sensitivity characteristic, the responsive phenomenon that unexpected interference noise or other frequencies cause occurs, also reduced the technical difficulty to signal controlling simultaneously.
But in the reality test, the equipment or the measured object that often run into belong to linear system, needn't consider the nonlinear response between many signals, such as the test cable at interval when spending, because radiation cable and disturbed cable itself can not produce unexpected interference noise, can inject a plurality of test signals simultaneously, test the isolation of a plurality of frequencies simultaneously.
Isolation (space isolation) be electromagnetic wave in the transmission course of space because the transmission medium loss, or factors such as the refraction in the delivering path, diffraction, reflection cause the measuring of decay of energy.Determine under the space condition, can determine as the distance between two objects, angle, relative position, transmission medium that then the space isolation between the object is definite constant.Therefore when the circuit types of two cables, position are definite, can obtain isolation between cable by test.
Owing to have nonlinear device in the equipment, service frequency signal causes service frequency signal to produce nonlinearities change and expanding service band at waveform by nonlinear device, multiple frequency in frequency of operation produces some new spectrum components, and the spectrum component on these frequency of operation multiple frequencies is referred to as harmonic wave.Harmonic wave not only can be wasted net horsepower and the frequency spectrums of operation generation of other equipment is disturbed, but because electronic equipment uses nonlinear device in a large number, causes harmonic phenomena very serious and general, and people have studied the whole bag of tricks and come harmonic carcellation.
In the research in electromagnetic compatibility field, always harmonic wave as the important disturbing factor that influences the electronic equipment Electro Magnetic Compatibility, the starting point of those skilled in the art research all is how to suppress harmonic wave, how to overcome the adverse effect of harmonic wave.
Summary of the invention
The present invention is directed to present test cable at interval in the process of degree, once can only test the frequency response of a frequency, when testing the broadband response between cable, need carry out single frequency point scanning to whole frequency band, long slow-footed problem of time, a kind of harmonic wave test cable that adopts has been proposed at interval from the method for spending, utilize harmonic signal in broad spectrum, to distribute, coupling belongs to the characteristics of linear system response between the cable, at interval test a plurality of frequencies simultaneously to improve test speed when spending at the test cable, once test the frequency response in the whole frequency range simultaneously, shorten the test duration of isolation.
This method comprises the steps:
Step 1: according to test frequency scope f
a-f
bWith frequency span accuracy f
iDemand determine harmonic wave fundamental frequency and overtone order.
According to test frequency scope f
a-f
bWith frequency span accuracy f
iDemand select harmonic signal fundamental frequency and overtone order, the frequency interval f between each harmonic frequency
cShould be smaller or equal to frequency span accuracy f
i, the minimum harmonic frequency of harmonic signal should be smaller or equal to the lower limit f of test frequency scope
a, maximum harmonic frequency should be more than or equal to the upper limit f of test frequency scope
b, the minimum harmonic number of times m * f of injection signal
c≤ f
a, inject the higher harmonics frequency n * f of signal
c〉=f
b
Step 2: produce harmonic signal and inject the interference cable;
Step 3: the intensity of cable and disturbed cable each harmonic is disturbed in test;
Step 4: calculate the isolation on each harmonic frequency point between cable, computing formula is L=(U
o+ R
1)-(U
i+ R
2), U
iFor disturbing the injection intensity of certain harmonic frequency point of harmonic signal in the cable, U
oFor coupled signal in the disturbed cable at the intensity of this harmonic frequency point, R
1The reception coefficient of the couple current checkout equipment that in disturbed cable, produces for harmonic signal electromagnetic coupled between cable, R
2In disturbing cable, inject the reception coefficient of signal intensity detection apparatus for certain harmonic frequency point of harmonic signal.
In above-mentioned test process, if the disturbed cable that uses in the step 3 with disturb the cable signal intensity detection apparatus to adopt through the identical signal intensity detection apparatus of verification and model to guarantee to receive coefficient (R
1, R
2) identical, then the isolation computing formula in the step 4 is reduced to L=U
o-U
i
If in step 3, take the method for test step by step for disturbed cable and interference cable signal intensity, use same signal detection apparatus, successively disturbed cable and interference cable signal intensity are detected, then the isolation computing formula in the step 4 is reduced to L=U
o-U
i
Use this method to carry out isolation detection between cable, by the traditional response that can only test a Frequency point at every turn, need repeatedly test just can finish the test of whole frequency range, change the response of once testing all the harmonic frequency points in the whole frequency range simultaneously into, shortened the test duration of isolation.
Description of drawings
The process flow diagram of Fig. 1 the method for the invention.
Embodiment
Fig. 1 is the bright process flow diagrams of we, specifies the implementation process of this method below in conjunction with example, and required in the present embodiment test frequency scope is 40-120MHz, and frequency resolution is 20MHz.
Step 1: determine harmonic wave fundamental frequency and overtone order.According to test frequency scope f
a-f
bWith frequency span accuracy f
iDemand select harmonic frequency signal, the frequency interval f between each harmonic frequency
cShould be smaller or equal to test frequency resolution f
i, the minimum harmonic frequency of harmonic signal should be smaller or equal to the lower limit f of frequency range
a, maximum harmonic frequency should be more than or equal to the upper limit f of test frequency scope
b, the minimum harmonic number of times m * f of injection signal
c≤ f
a, inject the higher harmonics frequency n * f of signal
c〉=f
b
Because required test frequency scope is 40-120MHz, frequency resolution is 20MHz, and the selection fundamental frequency is 20MHZ, and the minimum harmonic number of times is 2 times, and higher harmonics number of times is 6 times harmonic wave.
Step 2: produce harmonic wave and inject cable.
The fundamental frequency that is produced by harmonic signal generator (signal source or special oscillator) is 20MHz, and the minimum harmonic number of times is 2 times, and higher harmonics number of times is 6 times harmonic signal and injects tested cable.Can selective receiver or frequency spectrograph observe interference harmonic signal in the disturbed cable.All stable when injecting signal and coupled signal, adjust the intensity of injecting signal, guarantee that each harmonic frequency point produces in the harmonic signal minimum coupled signal intensity is greater than the end level 3dB that makes an uproar in disturbed cable.In the present embodiment, the coupled signal intensity minimum of disturbed harmonic wave when 40MHz, at this moment the end level of making an uproar at this frequency place is 15dB μ V, then can to survey minimum levels be 18dB μ V to this harmonic wave, in the present embodiment, in 40Mhz frequency place coupled signal strength control at 18.5dB μ V.
Step 3: the intensity of cable and disturbed cable each harmonic is disturbed in test.
When injecting signal and coupled signal and all stablized, begin to measure each harmonic frequency intensity of harmonic signal of injection interference cable and each harmonic frequency intensity of harmonic signal that the coupling of disturbed cable produces, the test frequency scope that covers is between 40Mhz and the 120Mhz, as table 1.
Can adopt computer generation to replace and manually finish kinetic measurement, data recording, result treatment work, further alleviate tester's work load.
Step 4: calculate the isolation on each harmonic frequency point between cable, computing formula is L=(U
o+ R
1)-(U
i+ R
2), U
iFor disturbing the harmonic signal that injects in the cable at the injection intensity of certain harmonic frequency point, U
oBe the coupled signal that in disturbed cable, the produces intensity at this harmonic frequency point, R
1Be the reception coefficient of the induced signal strength detection equipment that produces in the disturbed cable, R
2For disturbing the reception coefficient of the harmonic signal strength detection equipment that injects in the cable.
Use in the present embodiment through verification and the identical signal intensity detection apparatus of model and detect the signal intensity disturbed in cable and the disturbed cable to guarantee to receive coefficients R
1, R
2Identical; Also can take test step by step, use same signal intensity detection apparatus successively to test the injection interference signal intensity of disturbing cable, the coupled signal intensity on the disturbed cable, guarantee to receive coefficients R
1, R
2Identical, make computing formula be reduced to L=(U
o+ R
1)-(U
i+ R
2)=U
o-U
iThe test data of present embodiment and isolation result of calculation see Table 1.
| Overtone order | 2 | 3 | 4 | 5 | 6 |
| Resonance frequency (MHz) | 40 | 60 | 80 | 100 | 120 |
| Inject signal intensity U i(dBμV) | 26.5 | 31.2 | 35.2 | 30 | 20 |
| Coupled signal intensity U o(dBμV) | 18.5 | 24.3 | 21.8 | 21.4 | 14.4 |
| Isolation L (dB) between cable | 8.0 | 6.9 | 13.4 | 8.6 | 5.6 |
Test data in the table 1 test implementation example and isolation result of calculation
Claims (3)
1. one kind is adopted harmonic wave test cable at interval from the method for degree, it is characterized in that comprising the steps:
Step 1: according to test frequency scope f
a-f
bWith frequency span accuracy f
iDemand determine harmonic signal fundamental frequency and overtone order, require the minimum harmonic frequency of harmonic signal should be smaller or equal to the lower limit f of test frequency scope
a, maximum harmonic frequency should be more than or equal to the upper limit f of test frequency scope
b, the frequency interval f between each harmonic frequency
cShould be smaller or equal to frequency span accuracy f
i
Step 2: produce harmonic signal and inject the interference cable;
Step 3: the intensity of cable and disturbed cable each harmonic is disturbed in test;
Step 4: calculate the isolation on each harmonic frequency point between cable, computing formula is L=(U
o+ R
1)-(U
i+ R
2), U
iFor disturbing the injection intensity of certain harmonic frequency point of harmonic signal in the cable, U
oFor coupled signal in the disturbed cable at the intensity of this harmonic frequency point, R
1Be the reception coefficient of disturbed cable coupled signal strength detection equipment, R
2For disturbing the reception coefficient that injects signal intensity detection apparatus in the cable.
2. employing harmonic wave as claimed in claim 1 is tested cable at interval from the method for degree, it is characterized in that in step 3, measures disturbed cable harmonic signal intensity and disturbs the receiving equipment employing of coupled signal intensity in the cable to receive coefficients R
1, R
2Identical receiving equipment, the computing formula in its step 4 is reduced to L=U
o-U
i
3. employing harmonic wave test cable as claimed in claim 1 is at interval from the method for spending, it is characterized in that in step 3, the mode of same receiving equipment step measurement is adopted in the measurement of interference cable and disturbed cable each harmonic intensity, successively test the interference signal intensity of interfering line cable-end injection, the coupled signal intensity on the disturbed cable, the computing formula in its step 4 is reduced to L=U
o-U
i
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| CN101685125B true CN101685125B (en) | 2013-10-09 |
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| CN110297126A (en) * | 2018-03-21 | 2019-10-01 | 中国科学院金属研究所 | The frequency spectrum multiple scale analysis method of testing of instrumentation amplifier Frequency Response |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4160947A (en) * | 1976-10-26 | 1979-07-10 | Dainichi-Nippon Cables, Ltd. | Apparatus and method for electrically testing multi-core cable |
| CN1558687A (en) * | 2004-01-14 | 2004-12-29 | 中兴通讯股份有限公司 | Test apparatus and test method for isolation between antennas of wireless co-frequency direct amplifying station |
| CN1731714A (en) * | 2005-09-02 | 2006-02-08 | 中兴通讯股份有限公司 | System and method for testing RF module upstream channel gain and isolation degree |
| DE102005003248A1 (en) * | 2005-01-24 | 2006-07-27 | Infineon Technologies Ag | Power transistor gate isolation testing method for semiconductor device, involves applying test potential to wire and another test potential between gate contact and source contact to determine faulty current |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE10252869A1 (en) * | 2002-11-12 | 2004-05-27 | Pfalzwerke Ag | Voltage isolation test unit for multiple phase cables has sprung supported measurement electrodes in hinged semicircular ring clamped to insulation |
-
2008
- 2008-09-22 CN CN 200810215272 patent/CN101685125B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4160947A (en) * | 1976-10-26 | 1979-07-10 | Dainichi-Nippon Cables, Ltd. | Apparatus and method for electrically testing multi-core cable |
| CN1558687A (en) * | 2004-01-14 | 2004-12-29 | 中兴通讯股份有限公司 | Test apparatus and test method for isolation between antennas of wireless co-frequency direct amplifying station |
| DE102005003248A1 (en) * | 2005-01-24 | 2006-07-27 | Infineon Technologies Ag | Power transistor gate isolation testing method for semiconductor device, involves applying test potential to wire and another test potential between gate contact and source contact to determine faulty current |
| CN1731714A (en) * | 2005-09-02 | 2006-02-08 | 中兴通讯股份有限公司 | System and method for testing RF module upstream channel gain and isolation degree |
Non-Patent Citations (4)
| Title |
|---|
| 同平台天线间隔离度测试;陈玉东等;《电子测量技术》;20070331;第30卷(第3期);全文 * |
| 王冰切等.电子战特种飞机的天线隔离度测试.《宇航计测技术》.2007,第27卷(第3期),全文. |
| 电子战特种飞机的天线隔离度测试;王冰切等;《宇航计测技术》;20070531;第27卷(第3期);全文 * |
| 陈玉东等.同平台天线间隔离度测试.《电子测量技术》.2007,第30卷(第3期),全文. |
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