1、BRITISH STANDARD Fibre optic communication subsystem basic test procedures - Part 2.4: Test procedures for digital systems - Bit-rate tolerance measurement * rn * The European Standard EN 61280-241998 has the status of a British Standard ICs 33.180.01 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERM
2、ITTED BY COPYRIGHT LAW BS EN 61280-241998 IEC 61280-2-41998 BS EN 61280-2-431998 been prepared under the direction of the E1ectrotechnica.i Sector Board, was pubiished under the authority of the Standards Board and comes into effect on 16 November 1998 hd. No. O BSI 1998 ISBN O 6 30602 X National fo
3、reword Date Text affected This British Standard is the English language vemion of EN 61280-241998. It is identical with IEC 6128CL241998. The UK participation in its preparation was entrusted by Technid Committee GEM, Fibre optics, to Subcommittee GEL/86/3, Fibre optic systems and active devices, wh
4、ich has the responsibility to: - aid enquirers to understand the tea - present to the responsible inttxmtionavEuropean committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; - monitor related inteniational and European developments and promulgate
5、them in the TJK A list of organizations represented on this subcommittee can be obtained on request to its secretaxy. Rom 1 January 1997, ali IEC publications have the number 60000 added to the old number. For instance, IEC 27-1 has been renumbered as IEC 60027-1. For a period of time during the cha
6、nge over from one numbenng system to the other, publications may contain identifiers from both systems. Cross-references Attention is drawn to the fact that CEN and CENELEC Standards normally include an annex which lists normative references to international publications with their corresponding Eur
7、opean publicaiions The Brish Standards which implement international or European publications referred to in this document may be found in the BSI Standards Cataogue under the &on entitled “InMonal Standards Correspondence Jndex“, or by using the “Find“ Wty of the BSI Standards Electronic Catalogue.
8、 A British standard does not purport to include all the necessary provisions of a contract Users of British Stanars are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a
9、front cover, an inside hnt cover, the EN title page, pages 2 to 9 and a back cover. EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 61 280-2-4 August 1998 ICs 33.180.01 English version Fibre optic communication subsystem basic test procedures Part 2-4: Test procedures for digital systems Bit-ra
10、te tolerance measurement (IEC 61 280-2-4:1998) Procdures dessai de base des sous-systmes de tlcommunication fibres optiques Prfverfahren Partie 2-4: Procdures dessai des systmes numriques - Mesure de la Lichtwellenleiter-Kommunikations- untersysteme - Grundlegende Teil 2-4: Prfverfahren fr digitale
11、Systeme - Messung der - I tolrance sur le dbit binaire Bitraten-Toleranz - -i 5i (CE1 6 1 280-2-4: 1 998) (IEC 61 280-2-4:1998) - i = This European Standard was approved by CENELEC on 1998-08-01. CENELEC members are bound to comply with the CENXENELEC Internal Regulations which stipulate the conditi
12、ons 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 Central Secretariat or to any CENELEC member. This European Standard exists in thre
13、e official versions (English, French, German). A version in any other language made by translation under the responsibiiity of a CENELEC member into its own language and notified to the Central Secretariat has the same status as the officiai versions. CENELEC members are the national electrotechnica
14、l committees of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CENELEC European Committee for Eiectrotechnical Standardization Comit Europen de Normalisati
15、on Electrotechnique Europisches Komitee fr Elektrotechnische Normung Central Secretariat: rue de Stacsart 35, B - 1050 Brussels 1998 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members. Ref. No. EN 61 280-2-4: 1998 E Page 2 EN 61280-2-4:1998 Forew
16、ord The text of document 86C/183/FDIS, future edition 1 of IEC 61 280-2-4, prepared by SC 86C, Fibre optic systems and active devices, of IEC TC 86, Fibre optics, was submitted to the IEC-CENELEC parallel vote and was approved by CENELEC as EN 61 280-2-4 on 1998-08-01. The following dates were fixed
17、: - latest date by which the ER has to be implemented at national level by publication of an identical national standard or by endorsement (dopl 1999-05-01 - latest date by which the national standards conflicting with the EN have to be-withdrawn (daw) 2001 -05-01 Endorsement notice The text of the
18、International Standard IEC 61 280-2-4:1998 was approved by CENELEC as a European Standard without any modification. Page 3 EN 61280-2-4:1998 CONTENTS Clause Page 1 Scope and object 4 2 Apparatus . 4 3 Test sample 5 5 fest result . 5 4 Test pocedure 5 Figures 7 O BSI 1998 Page 4 EN 61280-2-41998 FIBR
19、E OPTIC COMMUNICATION SUBSYSTEM BASIC TEST PROCEDURES - Part 2-4: Test procedures for digital systems - Bit-rate tolerance measurement 1 Scope and object The object of this test procedure is to measure the bit-rate tolerance of the fibre optic digital subsystem under specified conditions. Bit-rate t
20、olerance is defined by the clock frequency range of the fibre optic digital subsystem which meets the specified bit error ratio. 2 Apparatus 2.1 The test set shall be capable of providing a pseudo random bit sequence to the system consistent with the signal format (puise shape, amplitude, etc.) requ
21、ired at the system input electrical interface of the transmitter device. BER test set (pulse pattern generator, error detector and frequency synthesizer) 2.2 Optical power meter The optical power meter, which has a resolution of at least 0,l dB, and which has been calibrated for the wavelength of op
22、eration for the equipment to be tested, shall be used. 2.3 Optical attenuator The attenuator shall be capable of attenuation in steps less than or equal to 0,l dB and should be able to provide total attenuation 5 dB to 10 dB more than the system gain. Care should be taken to avoid back reflection in
23、to the transmitter. 2.4 Jumper cable Unless otherwise specified, the test jumpers shall have physical and optical properties normally equal to those of the cable plant with which the equipment is intended to operate. The jumpers shall be 2 m to 5 m long, and shall contain fibres with coatings which
24、remove cladding light. Appropriate connectors shall be used. Single mode jumpers shall be deployed with 90 mm diameter loops. If the equipment is intended for multimode operation and the intended cable plant is unknown the fibre size shall be 62,5/125 pm. 2.5 Test transmitter The test transmitter sh
25、all have electrical, optical, and mechanical characteristics similar to those of nominal transmitters that are used in the specified fibre optic terminal device. Page 5 EN 61280-2-41998 3 Test sample The test sample shall be a specified fibre optic receiver. The system inputs and outputs shall be th
26、ose normally seen by the user of the system. The test receiver shall be installed in the measurement configuration as shown in figure 1. 4 Test procedure 4.1 Unless otherwise specified, standard operating conditions apply. The ambient or reference point temperature and humidity shall be specified. 4
27、.2 Apply appropriate terminal input voltage to the system under test. Follow appropriate standard (or extended) operating conditions. Allow sufficient time (30 min unless otherwise specified by the manufacturer) for the terminal under test to reach steady-state temperature and performance condition.
28、 4.3 Turn the measurement equipment on and allow the recommended warm-up and setting time to achieve the rated measurement performance. 4.4 As part of standard operating conditions, all the terminal inputs shall be fully loaded with the pseudo random data (maximum possible word length: typically 2+2
29、3 - 1). Select a channel to be monitored. Connect the terminal output of the receiver portion on the BER test set. 4.5 Adjust the bit rate of the pulse signal to the nominal value. I - 4.6 Connect the reference jumper cable from the output of the variable optical attenuator to * the optical power me
30、ter. m * 4.7 Adjust the optical attenuator to set the received power at the manufacturer specified minimum received power level. 4.8 The jumper cable shall be reconnected to the input connector of the receiver 4.9 Measure the bit error ratio. 4.10 Repeating step 4.9 change the pulse repetition frequ
31、ency. The bit error ratio versus the bit rate shall be measured by an applicable step Ab. Plot BER versus bit-rate (B) using a graph sheet similar to that in figure 2. Unless otherwise specified, A6 shall be 10 ppm of the nominal bit-rate. 4.11 The bit-rate tolerance is given as the difference betwe
32、en maximum and minimum bit- rates which satisfy the specified error ratio divided by the nominal bit-rate (ppm). 5 Test result 5.1 Required information 5.1.1 Date and title of the test. 5.1.2 The terminal equipment, transmitter and receiver identifications. Page 6 EN 61280-2-41998 5.1.3 Identificati
33、on of test method, specific operating conditions and procedures used. 5.1.4 Results of the test, including ambient or reference point temperature and humidity. 5.2 Available information 5.2.1 Identification of the test equipment used and the measurement uncertainty due to measurement inaccuracy and
34、the display resolution of the optical power meter, and frequency synthesizer. 5.2.2 Identification of the jumper cable parameters. 5.2.3 Names of test personnel. 5.2.4 Supply voltage(s) and/or current). 5.2.5 Inpuoutput measurement condition: connector model, type of transmitter and receiver, receiv
35、er input power level. 5.2.6 Recommended warm-up time (time required for temperature stabilization). 5.3 Specification information 5.3.1 Bit rate and input signal characteristics. 5.3.2 Bit error ratio, which the system usually satisfies. Page 7 EN 61280-2-4:1998 j . BER test set I A! Pulse pattern g
36、enerator Error detector i Data Reference Data jumper cable Test transmitter Reference jumper cable . Optical power meter Figure 1 - Bit-rate tolerance measurement configuration Page 8 EN 61280-2-41998 BER -80 -80 40 -20 O 20 40 80 80 . Bit-rate deviation (pprn) IEC 716198 Figure 2 - Sample graph she
37、et Page 9 EN 61280-2-4:1998 1 OE-3 1 OE4 1 OE-5 BER 1 OE-6 1 OE-7 1 OE-8 1 OE-9 10E-10 1 OE-1 1 10E-12 -80 -60 40 -20 0 20 40 60 80 Bit-rate deviation (ppm) IEC 715% Figure 3 - Sample plot of BER versus bit-rate BS EN 61280-24 1998 IEC 61280-2-4 1998 BSI 389 Chiswick High Road London w4 4AL BSI - Br
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