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

1、BSI Standards PublicationFibre optic communication subsystem test proceduresPart 2-2: Digital systems Optical eye pattern, waveform and extinction ratio measurementBS EN 61280-2-2:2012Incorporating corrigendum February 2015BS EN 61280-2-2:2012National forewordThis British Standard is the UK implemen

2、tation of EN 61280-2-2:2012. It is identical to IEC 61280-2-2:2012, incorporating corrigendum February 2015. It supersedes BS EN 61280-2-2:2008 which is withdrawn.The UK participation in its preparation was entrusted by Technical Committee GEL/86, Fibre optics, to Subcommittee GEL/86/3, Fibre optic

3、systems and active devices.A list of organizations represented on this committee can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. The British Standards Institution 2

4、015. Published by BSI Standards Limited 2015ISBN 978 0 580 89801 3ICS 33.180.01Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 March 2013.Amendments/corrigenda

5、 issued since publicationDate Text affected31 March 2015 Implementation of IEC corrigendum February 2015: Figure 11 updatedBRITISH STANDARDEUROPEAN STANDARD EN 61280-2-2 NORME EUROPENNE EUROPISCHE NORM December 2012CENELEC European Committee for Electrotechnical StandardizationComit Europen de Norma

6、lisation ElectrotechniqueEuropisches Komitee fr Elektrotechnische Normung Management Centre: Avenue Marnix 17, B - 1000 Brussels 2012 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members. Ref. No. EN 61280-2-2:2012 E ICS 33.180.01 Supersedes EN 612

7、80-2-2:2008 English version Fibre optic communication subsystem test procedures - Part 2-2: Digital systems - Optical eye pattern, waveform and extinction ratio measurement (IEC 61280-2-2:2012) Procdures dessai des sous-systmes de tlcommunications fibres optiques - Partie 2-2: Systmes numriques - Me

8、sure du diagramme de loeil optique,de la forme donde et du taux dextinction(CEI 61280-2-2:2012) Prfverfahren fr Lichtwellenleiter-Kommunikationsuntersysteme - Teil 2-2: Digitale Systeme - Messung des optischenAugendiagramms, der Wellenformund des Extinktionsverhltnisses(IEC 61280-2-2:2012) This Euro

9、pean Standard was approved by CENELEC on 2012-11-29. CENELEC members are bound to complywith the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standardthe status of a national standard without any alteration. Up-to-date lists and bibliographical references

10、concerning such national standards may be obtained onapplication to the CEN-CENELEC Management Centre or to any CENELEC member. This European Standard exists in three official versions (English, French, German). A version in any otherlanguage made by translation under the responsibility of a CENELEC

11、 member into its own language and notifiedto the CEN-CENELEC Management Centre has the same status as the official versions. CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus,the Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Repu

12、blic of Macedonia, France, Germany,Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland,Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. EN 61280-2-2:2012 - 2 - Foreword The text of document 8

13、6C/1043/CDV, future edition 4 of IEC 61280-2-2, 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 approved by CENELEC as EN 61280-2-2:2012. The following dates are fixed: latest date by which the document has to

14、 be implemented at national level by publication of an identical national standard or by endorsement (dop) 2013-08-29 latest date by which the national standards conflicting with the document have to be withdrawn (dow) 2015-11-29 This document supersedes EN 61280-2-2:2008. EN 61280-2-2:2012 includes

15、 the following significant technical changes with respect to EN 61280-2-2:2008: - additional definitions; - clarification of test procedures. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CENELEC and/or CEN shall not be held res

16、ponsible for identifying any or all such patent rights. Endorsement notice The text of the International Standard IEC 61280-2-2:2012 was approved by CENELEC as a European Standard without any modification. In the official version, for Bibliography, the following notes have to be added for the standa

17、rds indicated: IEC 60825-1 NOTE Harmonised as EN 60825-1. IEC 61281-1 NOTE Harmonised as EN 61281-1. BS EN 61280-2-2:2012- 3 - EN 61280-2-2:2012 Annex ZA (normative) Normative references to international publications with their corresponding European publications The following documents, in whole or

18、 in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. NOTE When an international publication has

19、been modified by common modifications, indicated by (mod), the relevant EN/HD applies. Publication Year Title EN/HD Year IEC 61280-2-3 - Fibre optic communication subsystem test procedures - Part 2-3: Digital systems - Jitter and wander measurements EN 61280-2-3 - BS EN 61280-2-2:2012 2 61280-2-2 IE

20、C:2012(E) CONTENTS 1 Scope . 6 2 Normative references . 6 3 Terms and definitions . 6 4 Apparatus . 7 4.1 General . 7 4.2 Reference receiver definition . 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 filt

21、er . 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 clean 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

22、 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 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 c

23、alculation . 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 Oscilloscope 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 si

24、gnals) . 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 BS EN 61280-2-2:201261280-2-2 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

25、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 Available information . 26 9.3 Specification information . 26 Bibliography 27 Figure 1 Optical eye pattern, waveform and extincti

26、on ratio measurement configuration . 8 Figure 2 Oscilloscope bandwidths commonly used in eye pattern measurements . 10 Figure 3 PLL jitter transfer function and resulting observed jitter transfer function 13 Figure 4 Histograms centred in the central 20 % of the eye used to determine the mean logic

27、one and 0 levels, b1and b0. 16 Figure 5 OMA measurement using the square wave method 18 Figure 6 Construction of the duty cycle distortion measurement . 20 Figure 7 Construction of the crossing percentage measurement 21 Figure 8 Construction of the risetime measurement with no reference receiver fil

28、tering . 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 population sizes . 26 Table 1 Frequency response characteristics 11 BS EN 61280-2-2:2012 6 61280-2-2 IEC:2012(E) FIBRE OPTIC COMMUNI

29、CATION 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 waveform

30、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. For un

31、dated 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 ter

32、ms 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 duty c

33、ycle 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 ratio r

34、atio 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 BS EN 61280-2-2:201261280-2-2 IEC:2012(E

35、) 7 3.6 eye height 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 e

36、ye diagram may not 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

37、jitter deviation 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 j

38、itter frequency, 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

39、 achieving consistent 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

40、eye diagram 3.13 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 Figur

41、e 1. Many transmitter 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

42、 reference receiver 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, r

43、eference 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 achieve reference receiver specifications. Use of a BS EN 61280-2-2:2012 8 61280-2-2 IEC:2012(E) low-pass f

44、ilter which alone achieves reference receiver specifications often will not result in a test system that achieves the required frequency response. 4.2 Reference receiver definition A reference receiver typically follows a fourth-order low-pass Bessel response. A well-defined low-pass frequency respo

45、nse will yield consistent results across all test systems that conform to the specification. A low-pass response reduces test system noise and approaches the bandwidth of the actual receiver that the transmitter will be paired with in an actual communications system. As signal transients such as ove

46、rshoot and ringing, which can lead to eye mask failures, are usually suppressed by the reduced bandwidth of the system receiver, it is appropriate to use a similar bandwidth in a transmitter test system. The Bessel phase response yields near constant group delay in the passband, which in turn result

47、s in minimal phase distortion of the time domain optical waveform. The bandwidth of the frequency response typically is set to 0,75 (75 %) of the signalling rate. For example, the reference receiver for a 10,0 GBd signal would have a 3 dB bandwidth of 7,5 GHz. For non-return to zero (NRZ) signals, t

48、his response has the smallest bandwidth that does not result in vertical or horizontal eye closure (inter-symbol interference). When the entire test system achieves the fourth-order Bessel low-pass response with a bandwidth of 75 % of the baud rate, this is referred to as a Bessel-Thomson reference

49、receiver. Return-to-zero (RZ) signals require a larger bandwidth reference receiver, but which has not been specified in any standards committees. Figure 1 Optical eye pattern, waveform and extinction ratio measurement configuration 4.3 Time-domain optical detection system 4.3.1 Overview The time-domain optical detection system displays the power of the optical waveform as a function of time. The optical detection system is comprised primarily of a linear optical-to-electrical (O/E) converter,