1、 TECHNICAL REPORT IEC TR 60728-6-1First edition 2006-12Cable networks for television signals, sound signals and interactive services Part 6-1: System guidelines for analogue optical transmission systems Reference number IEC/TR 60728-6-1:2006(E) Publication numbering As from 1 January 1997 all IEC pu
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8、AL REPORT IEC TR 60728-6-1First edition 2006-12Cable networks for television signals, sound signals and interactive services Part 6-1: System guidelines for analogue optical transmission systems PRICE CODE IEC 2006 Copyright - all rights reserved No part of this publication may be reproduced or util
9、ized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the publisher. International Electrotechnical Commission, 3, rue de Varemb, PO Box 131, CH-1211 Geneva 20, Switzerland Telephone: +41 22 919 02 11 Telefax: +41 22 919
10、03 00 E-mail: inmailiec.ch Web: www.iec.ch X For price, see current catalogue Commission Electrotechnique Internationale International Electrotechnical Commission 2 TR 60728-6-1 IEC:2006(E) CONTENTS FOREWORD.4 INTRODUCTION.6 1 Scope.7 2 Normative references.7 3 Terms, definitions, symbols and abbrev
11、iations7 3.1 Symbols 7 3.2 Abbreviations 7 4 Topologies used for optical transmission systems in cable networks 8 4.1 Point-to-point system.8 4.2 Point-to-multi-point system8 4.3 Multi-point-to-point system 9 4.4 Real wavelength division multiplex system 10 4.5 Combinations 10 5 Influences of equipm
12、ent and fibre parameters on the system performance .10 6 Optical modulation index 11 6.1 Single wavelength system .12 6.2 WDM systems .13 6.3 Choosing the right input level at the transmitter.13 7 Carrier-to-noise ratio 14 7.1 Short-haul links with a single transmitter .14 7.2 Long-haul point-to-poi
13、nt link 15 7.3 Multiple transmitter systems (WDM) 16 7.4 Transmission systems with optical fibre amplifier 16 8 Linearity .17 8.1 Composite second order (CSO).18 8.2 Composite triple beat (CTB) 20 9 Flatness .21 10 Output level21 Annex A (informative) Brillouin scattering in optical fibres22 Annex B
14、 (informative) Noise sources of optical transmission systems24 Annex C (informative) Non-linear distortion in optical transmission systems.29 Bibliography44 Figure 1 Point-to-point system .8 Figure 2 Point-to-multi-point system.9 Figure 3 Multipoint-to-point system 9 Figure 4 Real wavelength divisio
15、n multiplex system.10 Figure 5 Definition of OMI for an optical transmitter .12 Figure C.1 Distortion of Volterra series expansion .30 TR 60728-6-1 IEC:2006(E) 3 Figure C.2 Weighted second- and third-order distortion repartition for the 42 carriers frequency allocation map defined in Table C.1 of IE
16、C 60728-3 (software window capture) 31 Figure C.3 Polarization-mode dispersion in single-mode fibre 33 Figure C.4 Static curve of a laser showing the clipping effect.34 Figure C.5 Transmitted and back-scattered power in the range of the Brillouin threshold 35 Figure C.6 Cause of self-phase modulatio
17、n35 Figure C.7 CSO caused by laser chirping and chromatic dispersion.37 Figure C.8 CSO degradation without PDL 38 Figure C.9 CSO degradation with PDL = 0,5 dB 12 38 Figure C.10 Simulated and measured intermodulation due to laser clipping .39 Figure C.11 Zoom on a CTB 43 Table 1 Interdependencies bet
18、ween equipment and system properties and performance parameters.11 Table C.1 Weightings of HD2, HD3, IMD2 and IMD330 4 TR 60728-6-1 IEC:2006(E) INTERNATIONAL ELECTROTECHNICAL COMMISSION _ CABLE NETWORKS FOR TELEVISION SIGNALS, SOUND SIGNALS AND INTERACTIVE SERVICES Part 6-1: System guidelines for an
19、alogue optical transmission systems FOREWORD 1) The International 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 questio
20、ns concerning standardization in the electrical and electronic fields. To this end and in addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC Publication(s)
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26、onsible for any equipment declared to be in conformity with an IEC Publication. 6) All users should ensure that they have the latest edition of this publication. 7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and members of its techni
27、cal 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 publication, use of, or reliance upon, this IEC Publication or any other IEC P
28、ublications. 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 elements of this IEC Publication may be the subject
29、 of patent rights. IEC shall not be held responsible for identifying any or all such patent rights. The main task of IEC technical committees is to prepare International Standards. However, a technical committee may propose the publication of a technical report when it has collected data of a differ
30、ent kind from that which is normally published as an International Standard, for example “state of the art“. IEC 60728-6-1, which is a technical report, has been prepared by technical area 5: Cable networks for television signals, sound signals and interactive services, of IEC technical committee 10
31、0: Audio, video and multimedia systems and equipment. TR 60728-6-1 IEC:2006(E) 5 The text of this technical report is based on the following documents: Enquiry draft Report on voting 100/1078/DTR 100/1142A/RVC Full information on the voting for the approval of this technical report can be found in t
32、he report on voting indicated in the above table. This publication has been drafted in accordance with the ISO/IEC Directives, Part 2. A list of all the parts of the IEC 60728 series, under the general title Cable networks for television signals, sound signals and interactive services, can be found
33、on the IEC website. The committee has decided that the contents of this publication will remain unchanged until the 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,
34、withdrawn, replaced by a revised edition, or amended. A bilingual version of this publication may be issued at a later date. 6 TR 60728-6-1 IEC:2006(E) INTRODUCTION Standards of the IEC 60728 series deal with cable networks for television signals, sound signals and interactive services including equ
35、ipment, systems and installations for head-end reception, processing and distribution of sound and television signals and their associated data signals; processing, interfacing and transmitting all kinds of signals for interactive services using all applicable transmission media. All kinds of networ
36、ks like CATV-networks MATV-networks and SMATV-networks individual receiving networks and all kinds of equipment, systems and installations installed in such networks, are within this scope. The extent of this standardization work is from the antennas, special signal source inputs to the head-end or
37、other interface points to the network up to the terminal input. The standardization of any user terminals (i.e. tuners, receivers, decoders, multimedia terminals etc.) as well as of any coaxial and optical cables and accessories thereof is excluded. TR 60728-6-1 IEC:2006(E) 7 CABLE NETWORKS FOR TELE
38、VISION SIGNALS, SOUND SIGNALS AND INTERACTIVE SERVICES Part 6-1: System guidelines for analogue optical transmission systems 1 Scope This part of IEC 60728 provides guidelines and procedures for determining the overall performance of optical transmissions systems used in cable networks for televisio
39、n signals, sound signals and interactive services. It is based on the requirements for optical equipment defined in IEC 60728-6 and should be used together with this standard. The information provided is meant to help field engineers and network planners (system designers) in planning and designing
40、optical systems. Though this content is less dense than in a standard, basic knowledge about system parameters of cable networks is needed. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited a
41、pplies. For undated references, the latest edition of the referenced document (including any amendments) applies. IEC 60728-1, Cable networks for television signals, sound signals and interactive services Part 1: Methods of measurement and system performance IEC 60728-3, Cable networks for televisio
42、n signals, sound signals and interactive services Part 3: Active wideband equipment for coaxial cable networks IEC 60728-6, Cable networks for television signals, sound signals and interactive services Part 6: Optical equipment IEC 60793-2, Optical fibres Part 2: Product specifications General IEC 6
43、1931, Fibre optics Terminology 3 Terms, definitions, symbols and abbreviations For the purposes of this document, the terms, definitions, symbols and abbreviations given in IEC 60728-1, IEC 60728-6 and IEC/TR 61931 apply. 3.1 Symbols In addition to the symbols given in the above-mentioned references
44、, the following graphical symbol is used in the figures of this technical report. WDMwavelength division multiplexer 3.2 Abbreviations In addition to the abbreviations given in the above-mentioned references, the following abbreviations are used in this technical report. 2HD second harmonic distorti
45、on 8 TR 60728-6-1 IEC:2006(E) 3HD third harmonic distortion DFB distributed feedback DWDM dense wavelength division multiplex IIN induced intensity noise IMD2 second-order intermodulation IMD3 third-order intermodulation IM-DD intensity modulation direct detection I requivalent input noise current d
46、ensity of an optical receiver OMI optical modulation index MPI multi-path interference PMD polarization mode dispersion PMP point-to-multi-point PTP point-to-point RMS root-mean-square SBS stimulated Brillouin scattering WDM wavelength division multiplexer 4 Topologies used for optical transmission
47、systems in cable networks The overall performance of optical transmission systems depends on many parameters and conditions. Separating the applications into different categories simplifies the step-by-step analysis and leads to a better overview. A logical way to build up these categories is to dis
48、tinguish different network topologies because it can be assumed that the network architecture is always known in advance. Starting from this point of view the following five topologies can be identified as relevant for the user. 4.1 Point-to-point system Point-to-point (PTP) systems consist of a sin
49、gle optical transmitter and a single optical receiver connected by a single line of fibre (Figure 1). E O E OFigure 1 Point-to-point system This configuration can typically be found in trunk-line feeding areas cabled with coax (HFC networks). Both wavelengths, 1 310 nm and 1 550 nm, are used for these systems. Most of the optical budget is consumed by the fibre attenuation (long-distance system).
