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1、BS EN 3475-810:2009 ICS 49.06 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW BRITISH STANDARD Aerospace series Cables, electrical, aircraft use Test methods Part 810: Structural return loss 0 Licensed CopyChinese University of Hong Kong, 11/04/2009 07:32, Uncontrolled Copy, (
2、c) BSI This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 March 2009 BSI 2009 ISBN 978 0 580 62412 4 Amendments/corrigenda issued since publication DateComments BS EN 3475-810:2009 National foreword This British Standard is the UK implementat
3、ion of EN 3475-810:2009. The UK participation in its preparation was entrusted to Technical Committee ACE/6, Aerospace avionic electrical and fibre optic technology. A list of organizations represented on this committee can be obtained on request to its secretary. This publication does not purport t
4、o include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard cannot confer immunity from legal obligations. Licensed CopyChinese University of Hong Kong, 11/04/2009 07:32, Uncontrolled Copy, (c) BSI BS EN 3475-810:2009 EU
5、ROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 3475-810 February 2009 ICS 49.060 English Version Aerospace series - Cables, electrical, aircraft use - Test methods - Part 810: Structural return loss Srie arospatiale - Cbles lectriques usage aronautique - Mthodes dessais - Partie 810: Affaiblisse
6、ment de rflexion structurel Luft- und Raumfahrt - Elektrische Leitungen fr Luftfahrtverwendung - Prfverfahren - Teil 810: Rckfludmpfung This European Standard was approved by CEN on 11 July 2008. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions
7、 for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN Management Centre or to any CEN member. This European Standard exists in three off
8、icial versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as the official versions. CEN members are the national standards bodies of Austri
9、a, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMIT
10、TEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: Avenue Marnix 17, B-1000 Brussels 2009 CENAll rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 3475-810:2009: E Licensed CopyChinese Un
11、iversity of Hong Kong, 11/04/2009 07:32, Uncontrolled Copy, (c) BSI BS EN 3475-810:2009 EN 3475-810:2009 (E) 2 Contents Page Foreword 3? 1?Scope 4? 2?Normative references 4? 3?Definition 4? 4?Preparation of specimens .4? 5?Apparatus .4? 6?Methods 4? 7?Requirements .5? Licensed CopyChinese University
12、 of Hong Kong, 11/04/2009 07:32, Uncontrolled Copy, (c) BSI BS EN 3475-810:2009 EN 3475-810:2009 (E) 3 Foreword This document (EN 3475-810:2009) has been prepared by the Aerospace and Defence Industries Association of Europe - Standardization (ASD-STAN). After enquiries and votes carried out in acco
13、rdance with the rules of this Association, this Standard has received the approval of the National Associations and the Official Services of the member countries of ASD, prior to its presentation to CEN. This European Standard shall be given the status of a national standard, either by publication o
14、f an identical text or by endorsement, at the latest by August 2009, and conflicting national standards shall be withdrawn at the latest by August 2009. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and/or CENELEC shall not
15、be held responsible for identifying any or all such patent rights. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, F
16、inland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. Licensed CopyChinese University of Hong Kong, 11/04/2009 07:32, Uncontrolled
17、 Copy, (c) BSI BS EN 3475-810:2009 EN 3475-810:2009 (E) 4 1 Scope This standard specifies methods for measuring structural return loss for digital data transmission cable. It shall be used together with EN 3475-100. 2 Normative references The following referenced documents are indispensable for the
18、application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 3475-100, Aerospace series Cables, electrical, aircraft use Test methods Part 100: General EN 3475-805, Aer
19、ospace series Cables, electrical, aircraft use Test methods Part 805: Characteristic impedance 3 Definition The structural return loss is used for quantifying the level of the reflected signal and to represent the structural effects of the cable itself relative to its own impedance (Zc). The SRL res
20、ult is sensitive to how the characteristic impedance is centred about the load impedance. 4 Preparation of specimens Test specimen shall be of 100 metres minimum length. The ends of the cable under test must be prepared in such way that the assembly of the pairs/quads is maintained. The measurements
21、 may be performed on production drums and/or on the final delivery package from one direction. 5 Apparatus HF Network Analyser. One impedance transformer (balun) with the appropriate frequency range, impedance and balanced at least as well as the pair under test facilitates making measurements on sy
22、mmetric pairs under balanced conditions. 6 Methods The SRL is a calculated parameter. The SRL is obtained from the measured complex impedance open and short circuit, see EN 3475-805 Method C and the calculation of the fitted characteristic impedance. Licensed CopyChinese University of Hong Kong, 11/
23、04/2009 07:32, Uncontrolled Copy, (c) BSI BS EN 3475-810:2009 EN 3475-810:2009 (E) 5 Fitted characteristic impedance calculation: The following formula gives the cable characteristic impedance module in function of the frequency f(Hz). 2/3 32 2/1 1 0 f K f K f K KZf+= The K0 to K3 coefficients are e
24、xtracted from the following expression: = = = = = = = = = 3 2 1 0 1 3 1 2/5 1 2 1 2/3 1 2/5 1 2 1 2/3 1 1 2 1 2/3 11 1 2/3 11 1 2/3 / 1 / 1 / 1 / 1111 1111 1111 111 K K K K ffff ffff ffff fff N f Z f Z f Z Z N i i N i i N i i N i i N i i N i i N i i N i i N i i N i i N i i N i i N i i N i i N i i N
25、i i so N i i so N i i so N i so where Zo/s is the measured complex impedance obtained from open and short circuit measurement Zf(); Zf is the fitted characteristic impedance (); f is the frequency (Hz); N is the number of measured points. Structural return loss calculation: The SRL for cable pairs i
26、s obtained by the formula: fso fso ZZ ZZ SRL + = / / log 20 where SRL is expressed in dB. 7 Requirements The SRL values obtained shall not exceed the values specified in the product standard. Licensed CopyChinese University of Hong Kong, 11/04/2009 07:32, Uncontrolled Copy, (c) BSI BS EN 3475-810:20
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