1、BRITISH STANDARD BS EN 50289-1-7:2001 Communication cables Specifications for test methods Part 1-7: Electrical test methods Velocity of propagation The European Standard EN 50289-1-7:2001 has the status of a British Standard ICS 33.120.10 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COP
2、YRIGHT LAWBS EN 50289-1-7:2001 This British Standard, having been prepared under the direction of the Electrotechnical Sector Committee, was published under the authority of the Standards Committee and comes into effect on 15 September 2001 BSI 08-2001 ISBN 0 580 38300 8 National foreword This Briti
3、sh Standard is the official English language version of EN 50289-1-7:2001. The UK participation in its preparation was entrusted by Technical Committee EPL/46, Cables, wire and waveguides, RF connectors and accessories for communication and signalling, to Subcommittee EPL/46/1, Communication cables,
4、 which has the responsibility to: A list of organizations 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 Catalog
5、ue under the section entitled “International Standards 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 cor
6、rect application. Compliance with a British Standard 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; monito
7、r related international and European developments 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 9 and a back cover. The BSI copyright date displayed in this document indicates when the document was last iss
8、ued. Amendments issued since publication Amd. No. Date CommentsEUROPEAN STANDARD EN 50289-1-7 NORME EUROPENNE EUROPISCHE NORM June 2001 CENELEC European Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Cen
9、tral Secretariat: rue de Stassart 35, B - 1050 Brussels 2001 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members. Ref. No. EN 50289-1-7:2001 E ICS 33.120.20 English version Communication cables - Specifications for test methods Part 1-7: Electrica
10、l test methods - Velocity of propagation Cbles de communication - Spcifications des mthodes dessai Partie 1-7: Mthodes dessais lectriques - Vitesse de propagation Kommunikationskabel - Spezifikationen fr Prfverfahren Teil 1-7: Elektrische Prfverfahren - Ausbreitungsgeschwindigkeit This European Stan
11、dard was approved by CENELEC on 2001-03-01. CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concern
12、ing such national standards may be obtained on application to the Central Secretariat or to any CENELEC member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CENELEC member into it
13、s own language and notified to the Central Secretariat has the same status as the official versions. CENELEC members are the national electrotechnical committees of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway,
14、Portugal, Spain, Sweden, Switzerland and United Kingdom.EN 50289-1-7:2001 2 Foreword This European Standard was prepared by SC 46XC, Multicore, Multipair and Quad Data communication cables, of Technical Committee CENELEC TC 46X, Communication cables. The text of the draft was submitted to the formal
15、 vote and was approved by CENELEC as EN 50289-1-7 on 2001-03-01. The following dates were fixed: - latest date by which the EN has to be implemented at national level by publication of an identical national standard or by endorsement (dop) 2002-04-01 - latest date by which the national standards con
16、flicting with the EN have to be withdrawn (dow) 2004-04-01 This European Standard has been prepared under the European Mandate M/212 given to CENELEC by the European Commission and the European Free Trade Association. _ 3 EN 50289-1-7:2001 Contents Foreword 1 1 Scope .4 2 Normative references4 3 Def
17、initions4 4 Test method6 4.1 Equipment 6 4.2 Test sample 6 4.3 Procedure.6 4.3.1Calibration procedure 6 4.3.2Measuring procedure.6 5 Expression of test results.7 5.1 Phase measurement7 5.2 Calculation of velocity of propagation8 5.3 Resonance method .9 6 Test report9EN 50289-1-7:2001 4 1 Scope Part
18、1-7 of EN 50289 details the test methods to determine the velocity of propagation of the finished cables used in analogue and digital communication systems. It is to be read in conjunction with Part 1-1 of EN 50289, which contains essential provisions for its application. 2 Normative references This
19、 European Standard incorporates by dated or undated reference, provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publica
20、tions apply to this European Standard only when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies (including amendments). EN 50289-1-1 2001 Communication cables Specifications for tests methods - Part 1-1: Electrical test me
21、thods General requirements EN 50289-1-11 2001 Communication cables - Specifications for test methods - Part 1-11: Electrical test methods - Characteristic impedance, input impedance, return loss EN 50290-1-2 1) - Communication cables - Part 1-2: Definitions 3 Definitions For the purpose of this Euro
22、pean Standard, the definitions of EN 50290-1-2 apply in addition to the following ones. 3.1 velocity of propagation Phase velocity The phase velocity of propagation, p , as defined in EN 50290-1-2, is derived from the measurement of the phase constant at known frequencies:f 2 p = (1)1)At draft stage
23、 5 EN 50289-1-7:2001 Group velocity The group velocity of propagation, g , as defined in EN 50290-1-2, is derived from the measurement of the phase constant at known frequencies:f f 2 f 2 d df 2 1 2 1 2 g = = (2) where = velocity of propagation in m/s; g = group velocity of propagation in m/s; p = p
24、hase velocity of propagation in m/s; f = frequency, where f 2 f 1 ; = phase constant in radians/m at frequency f 2and f 1 . may be either derived from a transmission measurement as indicated below or from an open/short circuit measurement as explained in EN 50289-1-11. ()() = B sin A - 1 2A arctan L
25、 2 (3) o s Z Z A = (4) () o s - B = (5) where L = cable length in meter; |Z o | = magnitude of the input impedance of the cable with an open circuit at the cable end; |Z s | = magnitude of the input impedance of the cable with a short circuit at the cable end; o = phase angle of the input impedance
26、of the cable with an open circuit at the cable end; s = phase angle of the input impedance of the cable with a short circuit at the cable end. NOTE The velocity of propagation, group velocity and phase velocity are almost equal for frequencies greater than 1 MHz when measured on symmetric or coaxial
27、 cables (when the cables operate only in TEM mode).EN 50289-1-7:2001 6 4 Test method 4.1 Equipment As an alternative to a network analyser a generator and phase meter or vector voltmeter may be used. Accuracy of test set up shall be better than 1 %. 4.2 Test sample When symmetrical cables are to be
28、measured, the ends of the cable under test (CUT) shall be prepared, such that when connected to the terminals of the test equipment the twisting of the pairs/quads is maintained. 4.3 Procedure 4.3.1 Calibration procedure The phase shift of the test set-up shall be measured over the whole specified f
29、requency range. The whole frequency range shall be measured with a linear sweep. The calibration data shall be recorded to enable the test results to be corrected. Generator Receiver Ri Ri Impedance matching device when needed Figure 1 - Calibration set up 4.3.2 Measuring procedure The CUT shall be
30、connected to the terminators of the measuring devices/baluns. The set-up shall be optimised, such that the mismatching between the measuring ports and the CUT is minimised by the baluns and the impedance matching device. The phase shift shall be measured over the whole specified frequency range and
31、at the same frequency points as for the calibration procedure. The whole frequency range shall be measured with a linear sweep. All pairs/quads of the CUT shall be measured. 7 EN 50289-1-7:2001 Generator Receiver Ri Ri Cable under test Pair x Figure 2 - Measuring set-up 5 Expression of test results
32、5.1 Phase measurement For the evaluation of the velocity of propagation it is necessary to have full phase shift information. Normally phase meters and vector voltmeters measure the phase in the range of - and + . In this case the phase shift has to be transformed into a monotonic decreasing functio
33、n of frequency in the range of 0 and - (Figure 3). Some network analysers provide this function. + - Frequency 0 Figure 3 Phase shift expandedEN 50289-1-7:2001 8 As an example the following computation may be used. For I=2 To Number of frequency points K=0 WHILE Phase (I) Phase (I-1) K=K+1 Phase (I)
34、Phase (I)-Kx2 END While NEXT I 5.2 Calculation of velocity of propagation The velocity of propagation shall be calculated as follows taking into account the calibration : (f) = ( meas(f) cal(f)/ L (6) where meas(f) = expanded phase shift measured at measuring procedure; cal(f) = expanded phase shif
35、t measured at calibration procedure; L = length of CUT. Phase velocityf 2 p = (7) Group velocity Applying following equation: g (f) = 2 f 2- f 1 / (f 1 ) - (f 2 ) (8) f 2 = f + f/2 (9) f 1= f - f/2 (10) f 0,05 measured frequency range if f 1f maxthen f 2= f max where f min/ f max = lowest/highest me
36、asured frequency f min =f start+ f/2; 9 EN 50289-1-7:2001 f max =f stopt- f/2; g = velocity of propagation at Frequency f; = phase constant. 5.3 Resonance method The frequencies f sand f owhere f sis the frequency of the minimum voltage (maximum impedance) at the near end of a short-circuited cable
37、and f ois the frequency of the maximum voltage (minimum impedance) of an open circuited cable are measured according to open/short method as described in EN 50289-1-11. The frequency of the first maximum or minimum is designated f s/o1 , the second f s/o2 , etc. The propagation time T pnat the n thr
38、esonance (frequency f s/on ) is given by the formula s/on pn f 4 1 - 2n = T (11) The phase velocity of propagation is calculated using the following formula: p= L/T p (12) where L is the physical length of the cable in meter. NOTE The electrical length of the coupling device and the adapter should b
39、e taken into account. The accuracy can be improved by taking the mean values : f n= (f o+ f s )/2 (13) T pn= (T pon+ T psn )/2 (14) For best accuracy the cable terminations (short-circuit or open circuit) shall have the same electrical length. 6 Test report The test report shall include: - temperatu
40、re, - frequency range, - sample length, - the phase velocity, group velocity, propagation time and delay as required.BS EN 50289-1-7:2001 BSI 389 Chiswick High Road London W4 4AL BSI British Standards Institution BSI is the independent national body responsible for preparing British Standards. It pr
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