1、BRITISH STANDARD AEROSPACE SERIES BS EN 3475-805:2002 Cables, electrical, aircraft use Test methods Part 805: Characteristic impedance The European Standard EN 3475-805:2002 has the status of a British Standard ICS 49.060 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBS EN 34
2、75-805:2002 This British Standard, having been prepared under the direction of the Engineering Sector Policy and Strategy Committee, was published under the authority of the Standards Policy and Strategy Committee on 25 June 2002 BSI 25 June 2002 ISBN 0 580 39909 5 National foreword This British Sta
3、ndard is the official English language version of EN 3475-805:2002. The UK participation in its preparation was entrusted by Technical Committee ACE/6, Aerospace avionic electrical and fibre optic technology, to Subcommittee, ACE/6/2, Aerospace Cables, which has the responsibility to: A list of orga
4、nizations represented on this subcommittee can be obtained on request to its secretary. Cross-references The British Standards which implement international or European publications referred to in this document may be found in the BSI Standards Catalogue under the section entitled “International Sta
5、ndards Correspondence Index”, or by using the “Find” facility of the BSI Standards Electronic Catalogue. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Stan
6、dard does not of itself confer immunity from legal obligations. aid enquirers to understand the text; present to the responsible European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European development
7、s and promulgate them in the UK. Summary of pages This document comprises a front cover, an inside front cover, the EN title page, pages 2 to 5 and a back cover. The BSI copyright date displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No
8、. Date CommentsEUROPEANSTANDARD NORMEEUROPENNE EUROPISCHENORM EN3475805 June2002 ICS49.060 Englishversion AerospaceseriesCables,electrical,aircraftuseTest methodsPart805:Characteristicimpedance SriearospatialeCbleslectriquesusage aronautiqueMthodesdessaisPartie805:Impdance caractristique LuftundRaum
9、fahrtElektrischenLeitungenfrLuftfahrt VerwendungPrfverfahrenTeil805:Wellenwiderstand ThisEuropeanStandardwasapprovedbyCENon20January2002. CENmembersareboundtocomplywiththeCEN/CENELECInternalRegulationswhichstipulatetheconditionsforgivingthisEurope an Standardthestatusofanationalstandardwithoutanyalt
10、eration.Uptodatelistsandbibliographicalreferencesconcernings uchnational standardsmaybeobtainedonapplicationtotheManagementCentreortoanyCENmember. ThisEuropeanStandardexistsinthreeofficialversions(English,French,German).Aversioninanyotherlanguagemadebytra nslation undertheresponsibilityofaCENmemberi
11、ntoitsownlanguageandnotifiedtotheManagementCentrehasthesamestatusasthe official versions. CENmembersarethenationalstandardsbodiesofAustria,Belgium,CzechRepublic,Denmark,Finland,France,Germany,Greece, Iceland,Ireland,Italy,Luxembourg,Malta,Netherlands,Norway,Portugal,Spain,Sweden,SwitzerlandandUnited
12、Kingdom. EUROPEANCOMMITTEEFORSTANDARDIZATION COMITEUROPENDENORMALISATION EUROPISCHESKOMITEEFRNORMUNG ManagementCentre:ruedeStassart,36B1050Brussels 2002CEN Allrightsofexploitationinanyformandbyanymeansreserved worldwideforCENnationalMembers. Ref.No.EN3475805:2002EEN3475805:2002(E) 2 Foreword Thisdoc
13、ument(EN3475805:2002)hasbeenpreparedbytheEuropeanAssociationofAerospace Manufacturers(AECMA). AfterenquiriesandvotescarriedoutinaccordancewiththerulesofthisAssociation,thisStandardhas receivedtheapprovaloftheNationalAssociationsandtheOfficialServicesofthemembercountriesof AECMA,priortoitspresentatio
14、ntoCEN. ThisEuropeanStandardshallbegiventhestatusofanationalstandard,eitherbypublicationofanidentical textorbyendorsement,atthelatestbyDecember2002,andconflictingnationalstandardsshallbe withdrawnatthelatestbyDecember2002. AccordingtotheCEN/CENELECInternalRegulations,thenationalstandardsorganization
15、softhefollowing countriesareboundtoimplementthisEuropeanStandard:Austria,Belgium,CzechRepublic,Denmark, Finland,France,Germany,Greece,Iceland,Ireland,Italy,Luxembourg,Malta,Netherlands,Norway, Portugal,Spain,Sweden,SwitzerlandandtheUnitedKingdom.EN3475805:2002(E) 3 1 Scope Thisstandardspecifiesmetho
16、dsformeasuringthecharacteristicimpedanceofacable. ItshallbeusedtogetherwithEN3475100. 2 Normativereferences ThisEuropeanStandardincorporatesbydatedorundatedreferenceprovisionsfromotherpublications. Thesenormativereferencesarecitedattheappropriateplacesinthetextandthepublicationsarelisted hereafter.F
17、ordatedreferences,subsequentamendmentstoorrevisionsofanyofthesepublicationsapplyto thisEuropeanStandardonlywhenincorporatedinitbyamendmentorrevision.Forundatedreferencesthe latesteditionofthepublicationreferredtoapplies. EN3475100 AerospaceseriesCables,electrical,aircraftuseTestmethodsPart100:Genera
18、l EN3475804 AerospaceseriesCables,electrical,aircraftuseTestmethodsPart804:Velocityof propagation 3 Preparationofspecimens Theseshallbestrippedandpreparedforconnectiontothemeasuringdevice. 4 Methods 4.1 MethodA:measurementwithimpedancebridgeoncoaxialcable Lengthofsample: 3m Equipment:impedancemeasur
19、ingbridge Frequency:asindicatedintheproductstandard Measuringprinciple:theinputimpedanceofthesampleshallbemeasuredfirstwithitsendinopencircuit (Z co )andthenwithitsendinshortcircuit(Z cc ). Thecharacteristicimpedanceofthecableshallbecalculatedfromthesetwomeasurementsusingthe followingformula: cc co
20、c Z . Z Z = 4.2 MethodB:reflectometermeasurementoncoaxialcable Themeasurementshallbetakenusingthesameequipmentandonthesamesampleasforthevelocityof propagation,connectedinthesamewayaccordingtoEN3475804. ThecharacteristicimpedanceZ c ofthecableshallbecalculatedfromthereflectioncoefficientshownonthe os
21、cilloscopescreenusingtheformula: r - r + = 1 1 Z Z o c sothatZ o =valueinohmsofcharacteristicimpedanceincommonmode.EN3475805:2002(E) 4 Measurementof r shallbetakenonemetrefromthecableinput( t/3). Figure1 4.3 MethodC:shieldedsymmetriccablemeasurement Thecharacteristicimpedanceofthecableatthespecified
22、frequencyshallbederivedfromtheinput impedanceofalengthofcablewhenitsfarendisputinopenandshortcircuit,usingthefollowingformula: cc co c Z . Z Z = (1) Z co andZ cc shallbederivedfromthereflectioncoefficients r co and r cc attheinputofthelengthofcable, usingthefollowingformulas: co co b co 1 1 . Z Z r
23、- r + = (2) co cc b cc 1 1 . Z Z r - r + = (3) InwhichZ b isthecharacteristicimpedanceofthetestsetupattheplacewherethecableisconnected. 4.3.1 Apparatus Avectorielnetworkanalyserabletomakereflexionmeasurementononeportdevices Abalunwith: 1) coaxialportmatchedtothecharacteristicimpedanceZ c ofthenetwor
24、kanalyser; 2) symmetricalportwithcharacteristicimpedanceZ b =75 W . Seefigure2. Figure2EN3475805:2002(E) 5 4.3.2 Measurementprocedure Calibration Thescatteringparametersofthebalunshallbederivedfromthereflectioncoefficientsmeasuredatthe coaxialportofthebalunwhenitssymmetricalportisloadedasitfollows:
25、opencircuit r symco shortcircuit r symcc matchedZ b =75Wr symad bythefollowingformulas: s 11 = r symad (4) co sym cc sym co sym cc sym ad sym 2 s 22 r - r r - r - r = (5) s 12 .s 21 =( r symad - r symcc)(1s 22 )( 6 ) 4.3.3 Measurements Thevaluesofthereflectioncoefficientsatthecoaxialportofthebalunsh
26、allbemeasuredwiththe symmetricalportloadedbythelengthofcabletobemeasured,whenitsfarendisasitfollows: opencircuit r co shortcircuit r cc Thevaluesofthereflectionfactorattheinputofthecableshallbederivedfromtheabovevaluesbythe followingformulas: cc cc cc s s( s)s. s 11 22 11 12 21 = - -+ r r co co cc s
27、 s( s)s. s 11 22 11 12 21 = - -+ r r Z co andZ cc arederivedfromtheformulasgivenin(2)and(3). Z c isderivedfromtheformulagivenin(1). 5 Requirement Thecharacteristicimpedanceshallbewithinthelimitsindicatedintheproductstandard.BS EN 3475-805:2002 BSI 389 Chiswick High Road London W4 4AL BSI British Sta
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