IEC 61280-2-2-2012 Fibre optic communication subsystem test procedures - Part 2-2 Digital systems - Optical eye pattern waveform and extinction ratio measuremen.pdf

1、 IEC 61280-2-2 Edition 4.0 2012-10 INTERNATIONAL STANDARD Fibre optic communication subsystem test procedures Part 2-2: Digital systems Optical eye pattern, waveform and extinction ratio measurement IEC 61280-2-2:2012(E) colour inside THIS PUBLICATION IS COPYRIGHT PROTECTED Copyright 2012 IEC, Genev

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9、ERNATIONAL STANDARD Fibre optic communication subsystem test procedures Part 2-2: Digital systems Optical eye pattern, waveform and extinction ratio measurement INTERNATIONAL ELECTROTECHNICAL COMMISSION U ICS 33.180.01 PRICE CODE ISBN 978-2-83220-420-7 Registered trademark of the International Elect

10、rotechnical Commission Warning! Make sure that you obtained this publication from an authorized distributor. colour inside 2 61280-2-2 IEC:2012(E) CONTENTS FOREWORD . 4 1 Scope . 6 2 Normative references . 6 3 Terms and definitions . 6 4 Apparatus . 7 4.1 General . 7 4.2 Reference receiver definitio

11、n . 8 4.3 Time-domain optical detection system . 8 4.3.1 Overview . 8 4.3.2 Optical-to-electrical (O/E) converter . 9 4.3.3 Linear-phase low-pass filter . 9 4.3.4 Oscilloscope 10 4.4 Overall system response . 11 4.5 Oscilloscope synchronization system. 11 4.5.1 General . 11 4.5.2 Triggering with a c

12、lean clock . 12 4.5.3 Triggering using a recovered clock 12 4.5.4 Triggering directly on data . 13 4.6 Pattern generator 14 4.7 Optical power meter 14 4.8 Optical attenuator 14 4.9 Test cord . 14 5 Signal under test 14 6 Instrument set-up and device under test set-up 14 7 Measurement procedures . 15

13、 7.1 Overview . 15 7.2 Extinction ratio measurement 15 7.2.1 Configure the test equipment . 15 7.2.2 Measurement procedure 15 7.2.3 Extinction ratio calculation . 16 7.3 Eye amplitude . 17 7.4 Optical modulation amplitude (OMA) measurement using the square wave method 17 7.4.1 General . 17 7.4.2 Osc

14、illoscope triggering 17 7.4.3 Amplitude histogram, step 1 17 7.4.4 Amplitude histogram, step 2 18 7.4.5 Calculate OMA 18 7.5 Contrast ratio (for RZ signals) . 18 7.6 Jitter measurements 18 7.7 Eye width 19 7.8 Duty cycle distortion (DCD) . 19 7.9 Crossing percentage . 20 7.10 Eye height . 21 61280-2

15、-2 IEC:2012(E) 3 7.11 Q-factor/signal-to-noise ratio (SNR). 21 7.12 Rise time . 21 7.13 Fall time 22 8 Eye-diagram analysis using a mask 23 8.1 Eye mask testing using the no hits technique . 23 8.2 Eye mask testing using the hit-ratio technique . 24 9 Test result 26 9.1 Required information . 26 9.2

16、 Available information . 26 9.3 Specification information . 26 Bibliography 27 Figure 1 Optical eye pattern, waveform and extinction ratio measurement configuration . 8 Figure 2 Oscilloscope bandwidths commonly used in eye pattern measurements . 10 Figure 3 PLL jitter transfer function and resulting

17、 observed jitter transfer function 13 Figure 4 Histograms centred in the central 20 % of the eye used to determine the mean logic one and 0 levels, b 1and b 0 . 16 Figure 5 OMA measurement using the square wave method 18 Figure 6 Construction of the duty cycle distortion measurement . 20 Figure 7 Co

18、nstruction of the crossing percentage measurement 21 Figure 8 Construction of the risetime measurement with no reference receiver filtering . 22 Figure 9 Illustrations of several RZ eye-diagram parameters 23 Figure 10 Basic eye mask and coordinate system 24 Figure 11 Mask margins at different sample

19、 population sizes . 26 Table 1 Frequency response characteristics 11 4 61280-2-2 IEC:2012(E) INTERNATIONAL ELECTROTECHNICAL COMMISSION _ FIBRE OPTIC COMMUNICATION SUBSYSTEM TEST PROCEDURES Part 2-2: Digital systems Optical eye pattern, waveform and extinction ratio measurement FOREWORD 1) The Intern

20、ational Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international co-operation on all questions concerning standardization in the electrical and electr

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29、iance 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 possibility that some of the

30、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 IEC technical committee 86: Fi

31、bre optics. This fourth edition cancels and replaces the third edition published in 2008 and constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: a) additional definitions; b) clarification of test procedures. 61280

32、-2-2 IEC:2012(E) 5 The text of this standard is based on the following documents: CDV Report on voting 86C/1043/CDV 86C/1074/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 ac

33、cordance with the ISO/IEC Directives, Part 2. A list of all parts in 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 unt

34、il the stability 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. A bilingual version of this publication may be issued at a later

35、 date. IMPORTANT The colour inside logo on the cover page of this publication indicates that it contains colours which are considered to be useful for the correct understanding of its contents. Users should therefore print this document using a colour printer. 6 61280-2-2 IEC:2012(E) FIBRE OPTIC COM

36、MUNICATION SUBSYSTEM TEST PROCEDURES Part 2-2: Digital systems Optical eye pattern, waveform and extinction ratio measurement 1 Scope The purpose of this part of IEC 61280 is to describe a test procedure to verify compliance with a predetermined waveform mask and to measure the eye pattern and wavef

37、orm parameters such as rise time, fall time, modulation amplitude and extinction ratio. 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. Fo

38、r undated references, the latest edition of the referenced document (including any amendments) applies. IEC 61280-2-3, Fibre optic communication subsystem test procedures Part 2-3: Digital systems Jitter and wander measurements 3 Terms and definitions For the purposes of this document, the following

39、 terms and definitions apply. 3.1 amplitude histogram graphical means to display the power or voltage population distribution of a waveform 3.2 contrast ratio ratio of the nominal peak amplitude to the nominal minimum amplitude of two adjacent logical 1s when using return-to-zero transmission 3.3 du

40、ty cycle distortion DCD measure of the balance of the time width of a logical 1 bit to the width of a logical 0 bit, indicated by the time between the eye diagram nominal rising edge at the average or 50 % level and the eye diagram nominal falling edge at the average or 50 % level 3.4 extinction rat

41、io ratio of the nominal 1 level to the nominal 0 level of the eye diagram 3.5 eye diagram type of waveform display that exhibits the overall performance of a digital signal by superimposing all the acquired samples on a common time axis one unit interval in width 61280-2-2 IEC:2012(E) 7 3.6 eye heig

42、ht difference between the 1 level, measured three standard deviation below the nominal 1 level of the eye diagram, and 0 level, measured three standard deviations above the nominal 0 level of the eye diagram 3.7 eye mask constellation of polygon shapes that define regions where the eye diagram may n

43、ot exist, thereby effectively defining the allowable shape of the transmitter waveform 3.8 eye width time difference between the spread of the two crossing points of an eye diagram, each measured three standard deviations toward the centre of the eye from their nominal positions 3.9 jitter deviation

44、 of the logical transitions of a digital signal from their ideal positions in time manifested in the eye diagram as the time width or spread of the crossing point 3.10 observed jitter transfer function OJTF ratio of the displayed or measured jitter relative to actual jitter, versus jitter frequency,

45、 when a test system is synchronized with a clock derived from the signal being measured 3.11 reference receiver description of the frequency and phase response of a test system, typically a fourth-order Bessel-Thomson low-pass, used to analyze transmitter waveforms with the intent of achieving consi

46、stent results whenever the test system complies with this expected response 3.12 signal-to-noise ratio SNR similar to Q-factor, the ratio of the difference of the nominal 1 and 0 level of the eye diagram to the sum of the standard deviation of both the 1 level and the 0 level of the eye diagram 3.13

47、 unit interval for the NRZ signal, the unit interval is one bit period or the inverse of the signalling rate 4 Apparatus 4.1 General 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. Many transm

48、itter characteristics are derived from analysis of the transmitter time-domain waveform. Transmitter waveform characteristics can vary depending on the frequency response and bandwidth of the test system. To achieve consistent results, the concept of a reference receiver is used. The reference recei

49、ver definition defines the combined frequency and phase response of the optical-to-electrical converter, any filtering, and the oscilloscope. The reference receiver frequency response is typically a low pass filter design and is discussed in detail in 4.2. At high signalling rates, reference receiver frequency response can be difficult to achieve when configured using individual components. It is common to integrate the reference receiver within the oscilloscope system to