1、BRITISH STANDARD BS EN 60512-25-6:2004 Connectors for electronic equipment Tests and measurements Part 25-6: Test 25f: Eye pattern and jitter The European Standard EN 60512-25-6:2004 has the status of a British Standard ICS 31.220.10 BS EN 60512-25-6:2004 This British Standard was published under th
2、e authority of the Standards Policy and Strategy Committee on 9 August 2004 BSI 9 August 2004 ISBN 0 580 44239 X National foreword This British Standard is the official English language version of EN 60512-25-6:2004. It is identical with IEC 60512-25-6:2004. The UK participation in its preparation w
3、as entrusted by Technical Committee EPL/48, Electromechanical components and mechanical components, to Subcommittee EPL/48/2, Connectors for electronic equipment, which has the responsibility to: A list of organizations represented on this subcommittee can be obtained on request to its secretary. Cr
4、oss-references The British Standards which implement international or European publications referred to in this document may be found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or o
5、f British Standards Online. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. aid enquirers to understand the text;
6、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. Summary of pages This document comprises a front cover,
7、 an inside front cover, the EN title page, pages 2 to 17 and a back cover. The BSI copyright notice displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. Date CommentsEUROPEAN STANDARD EN 60512-25-6 NORME EUROPENNE EUROPISCHE NORM July 2
8、004 CENELEC European Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Central Secretariat: rue de Stassart 35, B - 1050 Brussels 2004 CENELEC - All rights of exploitation in any form and by any means reser
9、ved worldwide for CENELEC members. Ref. No. EN 60512-25-6:2004 E ICS 31.220.10 English version Connectors for electronic equipment - Tests and measurements Part 25-6: Test 25f: Eye pattern and jitter (IEC 60512-25-6:2004) Connecteurs pour quipements lectroniques - Essais et mesures Partie 25-6: Essa
10、i 25f: Diagramme de loeil et gigue (CEI 60512-25-6:2004) Steckverbinder fr elektronische Einrichtungen - Mess- und Prfverfahren Teil 25-6: Prfung 25f - Augendiagramm und Jitter (IEC 60512-25-6:2004) This European Standard was approved by CENELEC on 2004-07-01. CENELEC members are bound to comply wit
11、h the CEN/CENELEC Internal Regulations which stipulate the conditions 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 Secretari
12、at or to any CENELEC member. This European Standard exists in three official versions (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 o
13、fficial versions. CENELEC members are the national electrotechnical committees of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slo
14、venia, Spain, Sweden, Switzerland and United Kingdom. Foreword The text of document 48B/1429/FDIS, future edition 1 of IEC 60512-25-6, prepared by SC 48B, Connectors, of IEC TC 48, Electromechanical components and mechanical structures for electronic equipment, was submitted to the IEC-CENELEC paral
15、lel vote and was approved by CENELEC as EN 60512-25-6 on 2004-07-01. The following dates were fixed: latest date by which the EN has to be implemented at national level by publication of an identical national standard or by endorsement (dop) 2005-04-01 latest date by which the national standards con
16、flicting with the EN have to be withdrawn (dow) 2007-07-01 _ Endorsement notice The text of the International Standard IEC 60512-25-6:2004 was approved by CENELEC as a European Standard without any modification. _ Page2 EN60512256:2004CONTENTS FOREWORD.5 1 Introduction9 1.1 Scope9 1.2 Terms and defi
17、nitions 9 2 Test resources9 2.1 Equipment.9 2.2 Fixture.11 3 Test specimen11 3.1 Description11 4 Test procedure.11 4.1 General.11 4.2 Eye pattern13 4.3 Jitter15 5 Details to be specified.17 6 Test documentation17 Annex A (normative) Schematics of sample termination19 Annex B (informative) Eye patter
18、n interpretation Practical guidance23 Figure A.1 Single-ended terminations .19 Figure A.2 Differential (balanced) terminations .21 Figure B.1 Typical eye pattern response.23 Figure B.2 Eye pattern response showing eye height and eye width 25 Figure B.3 Eye pattern response with mask (no hits).27 Fig
19、ure B.4 Eye pattern response showing hits inside mask .29 Figure B.5 DSO automatic method, showing vertical limits approximately 20 mV apart, referenced in 4.3.1.3.2 31 Figure B.6 DSO Manual method, showing two vertical cursors one on each side of the eye, referenced in 4.3.1.4.1.33 Figure B.7 Metho
20、d D, pulse test single pattern, showing the pulse width, referenced in 4.3.2.4 35 Page3 EN60512256:2004CONNECTORS FOR ELECTRONIC EQUIPMENT TESTS AND MEASUREMENTS Part 25-6: Test 25f: Eye pattern and jitter 1 Introduction 1.1 Scope and object This part of IEC 60512 is applicable to electrical connect
21、ors, cable assemblies, or interconnection systems within the scope of IEC TC 48. This standard describes methods for measuring an eye pattern response and jitter in the time domain. 1.2 Terms and definitions For the purpose of this part of IEC 60512, the following terms and definitions apply. 1.2.1
22、eye pattern oscilloscope display of synchronized pseudo-random digital data (signal amplitude versus time), showing the superposition of accumulated output waveforms 1.2.2 jitter difference between the earliest and latest times at which a signal crosses a specified reference voltage level 1.2.3 bit
23、period time interval between the successive like edges (rise to rise or fall to fall) of the clock signal. This is the reciprocal of the clock frequency 1.2.4 skew difference in propagation delay between two signal paths 1.2.5 measurement system rise time rise time measured with fixture in place, wi
24、thout the specimen, and with filtering (or normalization). The rise time is typically measured from 10 % to 90 % levels 2 Test resources 2.1 Equipment 2.1.1 High speed pattern generator with clock output capable of producing a signal with specified rise and fall times and data pattern. Page4 EN60512
25、256:20042.1.2 Signal analyzer with external clock input capable of infinite persistence display. This is typically a digital sampling oscilloscope (DSO) with sampling head. It is preferred that the DSO have a masking capability. NOTE Make sure not to exceed the maximum allowable input ratings of the
26、 oscilloscope input ports. This will prevent costly damage and provide reliable measurements. Even signal excursions that are within the maximum allowable signal levels of the oscilloscope can result in unstable eye pattern responses. 2.2 Fixture 2.2.1 The test fixtures shall provide for proper sign
27、al(s) and ground pattern(s) and, if required, proper termination of adjacent signal lines. 2.2.2 When measuring a differential response, make sure that the test fixtures and test cables are delay matched to minimize the skew. It is recommended that the skew of the test cables and fixtures be less th
28、an 5 % of the bit period. 3 Test specimen 3.1 Description For this test procedure, the test specimen shall be as follows. 3.1.1 Separable connectors A mated connector pair. 3.1.2 Cable assembly Assembled connectors and cables, and mated connectors. 3.1.3 Sockets A socket and test device or a socket
29、and pluggable header adapter. 4 Test procedure 4.1 General 4.1.1 Allow sufficient time for the equipment to warm-up and stabilize (according to the equipment manufacturers instructions). 4.1.2 If the specimen does not have a single-ended characteristic impedance of 50 or a differential impedance of
30、100 , impedance matching pads should be used. The required values are calculated using the equations in Figures A.1 or A.2. Use standard resistors having values nearest the values calculated from these equations. 4.1.3 Adjust the data generator for proper signal characteristics. These include rise t
31、ime, amplitude, data rate, and encoding scheme. NOTE Rise time adjustments should be made using hardware filters at the signal source and not using software filtering on the analyzer. Page5 EN60512256:20044.1.4 Trigger the oscilloscope on the data generator clock signal, making sure the clock signal
32、 does not exceed the normal operating range of the clock input port. 4.1.5 Where possible, measure the eye pattern and/or jitter of the fixture and test cables without the specimen. Adjust the oscilloscope controls to display an eye pattern. The time base setting should be selected so that one unit
33、interval (bit period) occupies at least 50 % of the horizontal display. The vertical sensitivity should be selected so that the signal amplitude occupies 50 % to 100 % of the vertical display. See Annex B for examples. 4.2 Eye pattern 4.2.1 Method A, mask test 4.2.1.1 Set the oscilloscope to infinit
34、e persistence display mode and set data acquisition to stop after the required number of waveforms. 4.2.1.2 Insert the specimen and initiate data acquisition to generate a preliminary eye pattern. 4.2.1.3 After the preliminary eye pattern data has been acquired, display or create the desired mask. M
35、ake sure the eye pattern and mask are positioned with respect to each other and centered on the horizontal axis of the display). The mask should be placed (left to right) so that it best fits into the eye pattern. See Figures B.3 and B.4 for examples. 4.2.1.4 If available, enable the function on the
36、 DSO that counts the number of data points that fall within the mask (referred to as “mask hits”). 4.2.1.5 Initiate data acquisition to generate a new eye pattern. 4.2.1.6 After the data acquisition is completed, record the number of mask hits. If the automatic counting function (“hit counter”) is n
37、ot available on the DSO, count and record the number of mask hits. 4.2.1.7 If required by the referencing document, make a hard copy of the oscilloscope display. 4.2.2 Method B, eye opening test 4.2.2.1 Set the oscilloscope to infinite persistence display mode and set data acquisition to stop after
38、the required number of waveforms. 4.2.2.2 Insert the specimen and initiate data acquisition to generate the eye pattern. 4.2.2.3 After the eye pattern has been acquired, measure and record the eye height at a time corresponding to 50 % of the bit period (V at 50 % t). Measure and record the eye widt
39、h at a voltage level corresponding to 50 % of the signal amplitude (t at 50 % V). 4.2.2.4 If required by the referencing document, make a hard copy of the oscilloscope display. Page6 EN60512256:20044.3 Jitter 4.3.1 Method C, Pseudo-Random Bit Sequence (PRBS) test, (multiple pattern) 4.3.1.1 Display
40、the eye pattern per 4.2. 4.3.1.2 Center trace around the horizontal axis such that the entire eye pattern amplitude is visible on the display. 4.3.1.3 DSO, automatic method: 4.3.1.3.1 If the oscilloscope contains automatic statistical measurement capability, it is recommended to use the DSO function
41、s to measure the jitter at the eye crossing point. 4.3.1.3.2 When using manual measurement limits, ensure that the vertical limits are as close together as possible, but a maximum of 20 mV apart; see Figure B.5. 4.3.1.4 DSO, manual method: 4.3.1.4.1 If the automatic measurement function is not avail
42、able, position two vertical cursors, one on each side of the eye cross transition; see Figure B.6. 4.3.1.4.2 Read the jitter value from the delta (distance between) the cursor positions. 4.3.2 Method D, pulse test (single pattern) 4.3.2.1 Set the generator for a DC balanced test pattern. This shall
43、be a square wave or PRBS pattern at the specified frequency. 4.3.2.2 Set the oscilloscope to infinite persistence display mode, and adjust the vertical position to center the waveform vertically on the display, with the half amplitude at the center of the screen. 4.3.2.3 Adjust the generator to prod
44、uce the specified test pattern. This pattern may be chosen to simulate a long idle sequence, and is specific to the data pattern to be used in the application. It is typically a pattern of a logic “1” followed by 20 or more logic “0”s. For single ended measurements, measure the logic “1“ and logic “
45、0“ levels, and adjust the generator if necessary to ensure the half amplitude of the waveform is still at center screen. For differential measurements, measure the logic “1“ and logic “0“ levels of both channels. Adjust the generator to minimize the offset in voltage or time between channels. If any
46、 voltage offset is present between channels, the amount of offset shall be added to or subtracted from (as appropriate) the half-amplitude measurement point for the pulse width in 4.3.2.4. 4.3.2.4 Measure the width of the pulse that crosses the half-amplitude point (center screen), using cursors or
47、oscilloscope measurement functions; see Figure B.7. 4.3.2.5 Subtract the half-amplitude pulse width measured in 4.3.2.4 from the bit time (1 divided by the clock frequency of the generator) to obtain the jitter. Page7 EN60512256:20045 Details to be specified The following details shall be specified
48、in the reference document. 5.1 Signal rise time, amplitude, and clock frequency 5.2 Data pattern; for example, a (2 23 1) for PRBS or a 1 + (20 0) for pulse pattern 5.3 Single-ended or differential 5.4 Termination value (and tolerances) 5.5 Signal/ground pattern, including the number and location of
49、 signal and grounds to be wired for this test 5.6 Specimen environment impedance if other than 50 for single-ended or 100 for differential 5.7 Whether a hard copy of the oscilloscope display is required 5.8 Method A or B of evaluating eye pattern, (mask or eye opening) 5.8.1 Mask definition and position (if desired) relative to the eye pattern or clock 5.8.2 Number of waveforms or samples to be acquired in generating
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