1、BRITISH STANDARD BS EN 61280-2-4:1998 IEC 61280-2-4:1998 Fibre optic communication subsystem basic test procedures Part 2.4: Test procedures for digital systems Bit-rate tolerance measurement The European Standard EN61280-2-4:1998 has the status of a British Standard ICS 33.180.01BS EN61280-2-4:1998
2、 This British Standard, having been prepared under the direction of the Electrotechnical Sector Board, was published under the authority of the Standards Board and comes into effect on 15November1998 BSI 05-1999 ISBN 0 580 30602 X National foreword This British Standard is the English language versi
3、on of EN61280-2-4:1998. It is identical with IEC61280-2-4:1998. The UK participation in its preparation was entrusted by Technical Committee GEL/86, Fibre optics, to Subcommittee GEL/86/3, Fibre optic systems and active devices, which has the responsibility to: aid enquirers to understand the text;
4、present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. A list of organizations represented on this subcommitte
5、e can be obtained on request to its secretary. From1January1997, all IEC publications have the number60000added to the old number. For instance, IEC27-1 has been renumbered as IEC60027-1. For a period of time during the change over from one numbering system to the other, publications may contain ide
6、ntifiers 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 European publications. The British Standards which implement international or E
7、uropean publications referred to in this document may be found in the BSI Standards Catalogue 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 n
8、ecessary provisions of a contract. Users of British Standards 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 front cover, an inside front cover, pages i and ii, th
9、e EN title page, pages 2 to 6 and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Amendments issued since publication Amd. No. Date CommentsBS EN61280-2-4:1998 BSI 05-
10、1999 i Contents Page National foreword Inside front cover Foreword 2 Text of EN 61280-2-4 3ii blankEUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 61280-2-4 August 1998 ICS 33.180.01 English version Fibre optic communication subsystem basic test procedures Part 2-4: Test procedures for digital
11、systems Bit-rate tolerance measurement (IEC 61280-2-4:1998) Procdures dessai de base des sous-systmes de tlcommunication fibres optiques Partie 2-4: Procdures dessai des systmes numriques Mesure de la tolrance sur le dbit binaire (CEI61280-2-4:1998) Lichtwellenleiter-Kommunikations- untersysteme Gru
12、ndlegende Prfverfahren Teil 2-4: Prfverfahren fr digitale Systeme Messung der Bitraten-Toleranz (IEC61280-2-4:1998) This European Standard was approved by CENELEC on 1998-08-01. CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving th
13、is 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 three official versio
14、ns (English, French, German). A version in any other language made by translation under the responsibility of a CENELEC member into its own language and notified to the Central Secretariat has the same status as the official versions. CENELEC members are the national electrotechnical committees of A
15、ustria, 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 Electrotechnical Standardization Comit Europen de Normalisation Electrotechniq
16、ue Europisches Komitee fr Elektrotechnische Normung Central Secretariat: rue de Stassart 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 61280-2-4:1998 EEN61280-2-4:1998 BSI 05-1999 2 Foreword The text of do
17、cument86C/183/FDIS, future edition1of IEC61280-2-4, prepared by SC86C, Fibre optic systems and active devices, of IECTC86, Fibre optics, was submitted to the IEC-CENELEC parallel vote and was approved by CENELEC as EN61280-2-4 on1998-08-01. The following dates were fixed: Endorsement notice The text
18、 of the International Standard IEC61280-2-4:1998 was approved by CENELEC as a European Standard without any modification. Contents Page Foreword 2 1 Scope and object 3 2 Apparatus 3 3 Test sample 3 4 Test procedure 3 5 Test result 3 Figure 1 Bit-rate tolerance measurement configuration 4 Figure 2 Sa
19、mple graph sheet 5 Figure 3 Sample plot of BER versus bit-rate 6 latest date by which the EN has to be implemented at national level by publication of an identical national standard or by endorsement (dop) 1999-05-01 latest date by which the national standards conflicting with the EN haveto be withd
20、rawn (dow) 2001-05-01EN61280-2-4:1998 BSI 05-1999 3 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 tolerance is defined by the clock frequency range of the fibre optic digital subsyst
21、em which meets the specified bit error ratio. 2 Apparatus 2.1 BER test set (pulse pattern generator, error detector and frequency synthesizer) The test set shall be capable of providing a pseudo random bit sequence to the system consistent with the signal format (pulse shape, amplitude, etc.) requir
22、ed at the system input electrical interface of the transmitter device. 2.2 Optical power meter The optical power meter, which has a resolution of at least0,1dB, and which has been calibrated for the wavelength of operation for the equipment to be tested, shall be used. 2.3 Optical attenuator The att
23、enuator shall be capable of attenuation in steps less than or equal to0,1dB and should be able to provide total attenuation5dB to10dB more than the system gain. Care should be taken to avoid back reflection into the transmitter. 2.4 Jumper cable Unless otherwise specified, the test jumpers shall hav
24、e physical and optical properties normally equal to those of the cable plant with which the equipment is intended to operate. The jumpers shall be 2m to5m long, and shall contain fibres with coatings which remove cladding light. Appropriate connectors shall be used. Single mode jumpers shall be depl
25、oyed with90mm diameter loops. If the equipment is intended for multimode operation and the intended cable plant is unknown the fibre size shall be62,5/125 4m. 2.5 Test transmitter The test transmitter shall have electrical, optical, and mechanical characteristics similar to those of nominal transmit
26、ters that are used in the specified fibre optic terminal device. 3 Test sample The test sample shall be a specified fibre optic receiver. The system inputs and outputs shall be those normally seen by the user of the system. The test receiver shall be installed in the measurement configuration as sho
27、wn 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. 4.2 Apply appropriate terminal input voltage to the system under test. Follow appropriate standard (or extended) operating
28、 conditions. Allow sufficient time (30min unless otherwise specified by the manufacturer) for the terminal under test to reach steady-state temperature and performance condition. 4.3 Turn the measurement equipment on and allow the recommended warm-up and setting time to achieve the rated measurement
29、 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 +23 1). Select a channel to be monitored. Connect the terminal output of the receiver portion on the BER test set. 4.5 Adju
30、st the bit rate of the pulse signal to the nominal value. 4.6 Connect the reference jumper cable from the output of the variable optical attenuator to the optical power meter. 4.7 Adjust the optical attenuator to set the received power at the manufacturer specified minimum received power level. 4.8
31、The jumper cable shall be reconnected to the input connector of the receiver. 4.9 Measure the bit error ratio. 4.10 Repeating step4.9 change the pulse repetition frequency. The bit error ratio versus the bit rate shall be measured by an applicable step %b. Plot BER versus bit-rate (B) using a graph
32、sheet similar to that in Figure 2. Unless otherwise specified, %b shall be 10ppm of the nominal bit-rate. 4.11 The bit-rate tolerance is given as the difference between maximum and minimum bit-rates which satisfy the specified error ratio divided by the nominal bit-rate (ppm). 5 Test result 5.1 Requ
33、ired information 5.1.1 Date and title of the test. 5.1.2 The terminal equipment, transmitter and receiver identifications. 5.1.3 Identification of test method, specific operating conditions and procedures used. 5.1.4 Results of the test, including ambient or reference point temperature and humidity.
34、EN61280-2-4:1998 4 BSI 05-1999 5.2 Available information 5.2.1 Identification of the test equipment used and the measurement uncertainty due to measurement inaccuracy and the display resolution of the optical power meter, and frequency synthesizer. 5.2.2 Identification of the jumper cable parameters
35、. 5.2.3 Names of test personnel. 5.2.4 Supply voltage(s) and/or current(s). 5.2.5 Input/output measurement condition: connector model, type of transmitter and receiver, receiver input power level. 5.2.6 Recommended warm-up time (time required for temperature stabilization). 5.3 Specification informa
36、tion 5.3.1 Bit rate and input signal characteristics. 5.3.2 Bit error ratio, which the system usually satisfies. Figure 1 Bit-rate tolerance measurement configurationEN61280-2-4:1998 BSI 05-1999 5 Figure 2 Sample graph sheetEN61280-2-4:1998 6 BSI 05-1999 Figure 3 Sample plot of BER versus bit-ratebl
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