1、 Collection of SANS standards in electronic format (PDF) 1. Copyright This standard is available to staff members of companies that have subscribed to the complete collection of SANS standards in accordance with a formal copyright agreement. This document may reside on a CENTRAL FILE SERVER or INTRA
2、NET SYSTEM only. Unless specific permission has been granted, this document MAY NOT be sent or given to staff members from other companies or organizations. Doing so would constitute a VIOLATION of SABS copyright rules. 2. Indemnity The South African Bureau of Standards accepts no liability for any
3、damage whatsoever than may result from the use of this material or the information contain therein, irrespective of the cause and quantum thereof. ISBN 978-0-626-22808-8 SANS 61280-2-2:2009Edition 3IEC 61280-2-2:2008Edition 3SOUTH AFRICAN NATIONAL STANDARD Fibre optic communication subsystem test pr
4、ocedures Part 2-2: Digital systems Optical eye pattern, waveform and extinction ratio measurement This national standard is the identical implementation of IEC 61280-2-2:2008 and is adopted with the permission of the International Electrotechnical Commission. Published by SABS Standards Division 1 D
5、r Lategan Road Groenkloof Private Bag X191 Pretoria 0001Tel: +27 12 428 7911 Fax: +27 12 344 1568 www.sabs.co.za SABS SANS 61280-2-2:2009 Edition 3 IEC 61280-2-2:2008 Edition 3 Table of changes Change No. Date Scope National foreword This South African standard was approved by National Committee SAB
6、S TC 79, Fibre optics, in accordance with procedures of the SABS Standards Division, in compliance with annex 3 of the WTO/TBT agreement. This SANS document was published in November 2009. This SANS document supersedes SANS 61280-2-2:2006 (edition 2). IEC 61280-2-2Edition 3.0 2008-03INTERNATIONAL ST
7、ANDARD NORME INTERNATIONALEFibre optic communication subsystem test procedures Part 2-2: Digital systems Optical eye pattern, waveform and extinction ratio measurement Procdures dessai des sous-systmes de tlcommunications fibres optiques Partie 2-2: Systmes numriques Mesure du diagramme de lil optiq
8、ue, de la forme donde et du taux dextinction INTERNATIONAL ELECTROTECHNICAL COMMISSION COMMISSION ELECTROTECHNIQUE INTERNATIONALE UICS 33.180.01 PRICE CODECODE PRIXISBN 2-8318-9637-1SANS 61280-2-2:2009This s tandard may only be used and printed by approved subscription and freemailing clients of the
9、 SABS . 2 61280-2-2 IEC:2008 CONTENTS FOREWORD.4 1 Scope and object6 2 Normative references6 3 Apparatus.6 3.1 Time-domain optical detection system7 3.1.1 Optical-to-electrical (O/E) converter .7 3.1.2 Resistive signal splitter (optional).8 3.1.3 Linear-phase low-pass filter .8 3.1.4 Oscilloscope 10
10、 3.1.5 Overall system response10 3.2 Oscilloscope synchronization system .10 3.3 Pulse pattern generator .11 3.4 Optical power meter.11 3.5 Optical attenuator 11 3.6 Test cord.11 4 Test sample11 5 Procedure.12 5.1 Method 1: Basic waveform measurement .12 5.2 Method 2: Extinction measurement method u
11、sing the histogram function.12 6 Calculation .14 6.1 Basic waveform measurement definitions.14 6.2 Method 2: Extinction measurement method using the histogram function17 6.3 Eye-diagram analysis using a mask .18 7 Test result 19 7.1 Required information .19 7.2 Available information .19 7.3 Specific
12、ation information20 Annex A (informative) Oscilloscope synchronization system23 Bibliography27 Figure 1 Optical eye pattern, waveform, and extinction ratio measurement configuration .6 Figure 2 Time-domain optical detection system 7 Figure 3 Illustrations of NRZ and RZ eye-diagram parameters 17 Figu
13、re 4 Example of eye pattern measured with 0,75/T low-pass filter.18 Figure 5 Example of eye pattern measured with 3,0/T low-pass filter.19 Figure 6 Eye diagram with vertical histogram data collected from the central 20 % window19 Figure A.1 Oscilloscope synchronization system .23 Table 1 Frequency r
14、esponse characteristics .10 Table 2 Typical parameters for the measurement shown in Figure 4 .21 SANS 61280-2-2:2009This s tandard may only be used and printed by approved subscription and freemailing clients of the SABS .61280-2-2 IEC:2008 3 Table 3 Typical parameters for the measurement shown in F
15、igure 5 .22 Table A.1 Example lengths of common RG-58 cable.25 SANS 61280-2-2:2009This s tandard may only be used and printed by approved subscription and freemailing clients of the SABS . 4 61280-2-2 IEC:2008 INTERNATIONAL ELECTROTECHNICAL COMMISSION _ FIBRE OPTIC COMMUNICATION SUBSYSTEM TEST PROCE
16、DURES Part 2-2: Digital systems Optical eye pattern, waveform and extinction ratio measurement FOREWORD 1) The IEC (International Electrotechnical Commission) is a worldwide organization for standardization comprising all national electrotechnical committees (IEC National Committees). The object of
17、the IEC is to promote international co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and in addition to other activities, the IEC publishes International Standards, Technical Specifications, Technical Reports, Publicly Available Specificat
18、ions (PAS) and Guides (hereafter referred to as “IEC Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with may participate in this preparatory work. International, governmental and non-governmental organizations liai
19、sing with the IEC also participate in this preparation. The IEC collaborates closely with the International Organization for Standardization (ISO) in accordance with conditions determined by agreement between the two organizations. 2) The formal decisions or agreements of the IEC on technical matter
20、s express, as nearly as possible, an international consensus of opinion on the relevant subjects since each technical committee has representation from all interested National Committees. 3) IEC Publications have the form of recommendations for international use and are accepted by IEC National Comm
21、ittees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any misinterpretation by any end user. 4) In order to promote international unification, IEC Nati
22、onal Committees undertake to apply IEC International Standards transparently to the maximum extent possible in their national and regional standards. Any divergence between the IEC Standard and the corresponding national or regional standard shall be clearly indicated in the latter. 5) The IEC provi
23、des no marking procedure to indicate its approval and cannot be rendered responsible for any equipment declared to be in conformity with one of its standards. 6) All users should ensure that they have the latest edition of this publication. 7) No liability shall attach to IEC or its directors, emplo
24、yees, servants or agents including individual experts and members of its technical committees and IEC National Committees for any personal injury, property damage or other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and expenses arising out of the
25、 publication, use of, or reliance upon, this IEC Publication or any other IEC Publications. 8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is indispensable for the correct application of this publication. 9) Attention is drawn to the p
26、ossibility that some of the elements of this IEC Publication may be the subject of patent rights. IEC shall not be held responsible for identifying any or all such patent rights. International Standard IEC 61280-2-2 has been prepared by subcommittee 86C: Fibre optic systems and active devices, of IE
27、C technical committee 86: Fibre optics. This third edition cancels and replaces the second edition published in 2005 and constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: a) The necessity of DC coupling for extin
28、ction ratio measurement is clarified. b) The definition of extinction ratio has been revised to better harmonize with ITU-T. c) The definition of OMA has been clarified. SANS 61280-2-2:2009This s tandard may only be used and printed by approved subscription and freemailing clients of the SABS .61280
29、-2-2 IEC:2008 5 The text of this standard is based on the following documents: CDV Report on voting 86C/768/CDV 86C/801/RVC Full information on the voting for the approval of this standard can be found in the report on voting indicated in the above table. This publication has been drafted in accorda
30、nce with the ISO/IEC Directives, Part 2. A list of all parts of the IEC 61280 series, published under the general title Fibre optic communication subsystem test procedures, can be found on the IEC website. The committee has decided that the contents of this publication will remain unchanged until th
31、e maintenance result date indicated on the IEC web site under “http:/webstore.iec.ch“ in the data related to the specific publication. At this date, the publication will be reconfirmed; withdrawn; replaced by a revised edition; or amended. SANS 61280-2-2:2009This s tandard may only be used and print
32、ed by approved subscription and freemailing clients of the SABS . 6 61280-2-2 IEC:2008 FIBRE OPTIC COMMUNICATION SUBSYSTEM TEST PROCEDURES Part 2-2: Digital systems Optical eye pattern, waveform and extinction ratio measurement 1 Scope and object The purpose of this part of IEC 61280 is to describe
33、a test procedure to measure the eye pattern and waveform parameters such as rise time, fall time, overshoot, and extinction ratio. Alternatively, the waveform may be tested for compliance with a predetermined waveform mask. 2 Normative references The following referenced documents are indispensable
34、for the 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. ITU-T Recommendation G.957, Optical interfaces for equipments and systems relating to the synchronous
35、digital hierarchy 3 Apparatus The primary components of the measurement system are a photodetector, a low-pass filter, an oscilloscope, and an optical power meter, as shown in Figure 1. Pulse pattern generator Optical transmitter Optical attenuator (Clock) Data Test cordTest cord Optical interface p
36、oint Time-domain optical detection system Trigger O/ E convertor Low-pass filter Oscilloscope Optical power meter IEC 1 519/98 Figure 1 Optical eye pattern, waveform, and extinction ratio measurement configuration SANS 61280-2-2:2009This s tandard may only be used and printed by approved subscriptio
37、n and freemailing clients of the SABS .61280-2-2 IEC:2008 7 3.1 Time-domain optical detection system The time-domain optical detection system displays the intensity of the optical waveform as a function of time. The optical detection system is comprised primarily of an optical-to-electrical (O/E) co
38、nverter, a linear-phase low-pass filter and an oscilloscope. The detection system is shown in Figure 2. More complete descriptions of the equipment are listed in the following subclauses. Optional amplifier Optical signal input Optical interface point Optical to electrical converter Oscilloscope ver
39、tical Oscilloscope synchronization signal Trigger Resistive signal splitter (optional) To synchronization system (optional) Low-pass filter IEC 1 520/98 Figure 2 Time-domain optical detection system 3.1.1 Optical-to-electrical (O/E) converter The O/E converter is typically a high-speed photodiode fo
40、llowed by electrical amplification. The O/E converter is equipped with an appropriate optical connector to allow connection to the optical interface point, either directly or via an optical test cord. The O/E converter (including any optional amplification following the O/E converter) shall be able
41、to reproduce the optical waveform with sufficient fidelity to ensure a meaningful measurement. Precise specifications are precluded by the large variety of possible implementations, but general guidelines are as follows: a) acceptable input wavelength range, adequate to cover the intended applicatio
42、n; b) input optical reflectance, low enough to avoid excessive back-reflection into the transmitter being measured; For example, assume that an optical transmitter is specified to tolerate 24 dB reflectance maximum. If the input reflectance of the O/E converter is 30 dB, the converter can be directl
43、y connected to the transmitter. If, however, the input reflectance of the O/E converter is 14 dB, a common value, the effective reflectance can be lowered to 24 dB (or less) by inserting either an optical isolator or a low-reflectance attenuator of 5 dB (or more) between the transmitter and the O/E
44、converter. c) responsivity, adequate to produce a readable display on the oscilloscope; SANS 61280-2-2:2009This s tandard may only be used and printed by approved subscription and freemailing clients of the SABS . 8 61280-2-2 IEC:2008 For example, assume that a non-return-to-zero (NRZ) optical data
45、stream with an average optical power of 15 dBm is to be measured. If the sensitivity of the oscilloscope is 10 mV per division, a responsivity of 790 V/W is required in order to produce a display of 50 mV peak-to-peak (that is, five divisions peak-to-peak). d) optical noise-equivalent power, low eno
46、ugh to result in an accurately measurable display on the oscilloscope; For example, assume that a non-return-to-zero (NRZ) optical data stream with an average optical power of 15 dBm is to be measured. If the effective noise bandwidth of the measurement system is 470 MHz, and if the displayed root-m
47、ean-square noise is to be less than 5 % of the eye pattern peak-to-peak height, the optical noise-equivalent power shall be 145 pW Hz-1/2or less. e) lower cut-off (3 dB) frequency, 0 Hz; DC coupling is necessary for two reasons. First, extinction ratio measurements cannot otherwise be performed. Sec
48、ond, if AC-coupling is used, low-frequency spectral components of the measured signal (below the lower cut-off frequency of the O/E converter) may cause significant distortion via amplitude modulation of the detected waveform. f) upper cut-off (3 dB) frequency, greater than the bandwidth of the low-
49、pass filter following the O/E converter; In order to ensure repeatability and accuracy, a low-pass filter of known characteristics is inserted in the signal path before the oscilloscope. This filter alone should primarily determine the effective system bandwidth. However, the response of the entire measurement system should conform to the desired frequency response. g) transient response, overshoot, undershoot and other waveform aberrations minor so as not to interfer
