1、BSI Standards PublicationCable networks for television signals, sound signals and interactive servicesPart 10-1: Guidelines for the implementation of return paths in cable networksPD CLC/TR 50083-10-1:2014National forewordThis Published Document is the UK implementation of CLC/TR 50083-10-1:2014. It
2、 supersedes PD CLC/TR 50083-10-1:2009 which is withdrawn.The UK participation in its preparation was entrusted by Technical Committee EPL/100, Audio, video and multimedia systems and equipment, to Subcommit-tee EPL/100/4, Cable distribution equipment and systems.A list of organizations represented o
3、n this committee can be obtained onrequest 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 2014.Published by BSI Standards Limited 2014ISBN 978 0 580 85318 0
4、ICS 33.060.40Compliance with a British Standard cannot confer immunity fromlegal obligations.This Published Document was published under the authority of theStandards Policy and Strategy Committee on 30 June 2014.Amendments/corrigenda issued since publicationDate Text affectedPUBLISHED DOCUMENTPD CL
5、C/TR 50083-10-1:2014TECHNICAL REPORT RAPPORT TECHNIQUE TECHNISCHER BERICHT CLC/TR 50083-10-1 June 2014 ICS 33.060.40 Supersedes CLC/TR 50083-10-1:2009 English Version Cable networks for television signals, sound signals and interactive services - Part 10-1: Guidelines for the implementation of retur
6、n paths in cable networks Rseaux de distribution par cbles pour signaux de tlvision, signaux de radiodiffusion sonore et services interactifs - Partie 10-1: Lignes directrices relatives la mise en oeuvre de la voie de retour dans les rseaux cbls Kabelnetze fr Fernsehsignale, Tonsignale und interakti
7、ve Dienste - Teil 10-1: Leitfaden fr die Einrichtung von Rckkanlen in Kabelnetzen This Technical Report was approved by CENELEC on 2014-06-02. CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic, Denmark, Estonia, Finland, F
8、ormer Yugoslav Republic 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. European Committee for Electrotech
9、nical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels 2014 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members. Ref. No
10、. CLC/TR 50083-10-1:2014 E PD CLC/TR 50083-10-1:2014CLC/TR 50083-10-1:2014 - 2 - Contents Foreword . 5 1 Scope . 6 1.1 General 6 1.2 Specific scope of this Technical Report . 6 2 Normative references . 6 3 Terms, definitions, symbols and abbreviations 7 3.1 Terms and definitions. 7 3.2 Symbols . 10
11、3.3 Abbreviations . 11 4 Network architecture 13 4.1 HFC architecture 13 4.2 Upgrade alternatives 15 4.3 Active or passive return path . 25 4.4 In building network . 25 4.5 In home network 25 5 Network design . 26 5.1 Considerations . 26 5.2 Return path loss, path loss difference and return path slo
12、pe 26 5.3 Noise and nonlinearity, optimizing signal levels 31 5.4 Isolation between outlets . 33 5.5 Equalization and filtering in return paths 33 6 Channel planning . 36 6.1 Purpose of this section. 36 6.2 Introduction 36 6.3 Summary 36 6.4 Considerations for channel planning . 37 6.5 Common path d
13、istortion products 41 6.6 European upstream bandwidths 41 6.7 Channel width 41 6.8 QPSK/16QAM operation and channel widths 41 6.9 Available return path spectrum (Table 8). 42 6.10 Channel plans 43 6.11 Network radiation . 45 7 Equipment for return path implementation . 45 7.1 General 45 7.2 Return p
14、ath amplifiers 45 8 Installation and maintenance 48 PD CLC/TR 50083-10-1:2014- 3 - CLC/TR 50083-10-1:2014 8.1 Signal level adjustment 48 8.2 Monitoring and measurements 52 Annex A (informative) Interference on return path 54 A.1 Multiple interference . 54 A.2 Impulse interference 63 A.3 Interference
15、 from home terminals EMC standards of home terminals . 65 A.4 Hum modulation . 66 A.5 Common path distortion (CPD) 66 Annex B (informative) Null packet and PRBS definitions . 74 B.1 Null packet definition 74 B.2 PRBS definition 74 Annex C (informative) ITU DWDM grid 75 Bibliography 77 Figures Figure
16、 1 Typical HFC topology 14 Figure 2 Regional network . 15 Figure 3 Trunk-and-distribution architecture using only coaxial equipment 15 Figure 4 HFC system . 16 Figure 5 Generic diagram showing the mapping of nodes and CMTS(s) to segments . 17 Figure 6 Segment comprising a single CMTS to N optical no
17、des . 17 Figure 7 Spectrum allocation bandwidth 18 Figure 8 Basic node architecture . 19 Figure 9 Re-arranged feeds (two CMTS serving four nodes) 20 Figure 10 Optical node with frequency stacking 21 Figure 11 Divided node 21 Figure 12 Return path segmentation . 22 Figure 13 Division of the node area
18、s using additional fibres . 22 Figure 14 DWDM (CWDM) return path transmission 23 Figure 15 Digital return technology basic concept . 23 Figure 16 Two return paths multiplexed to the transmission stream . 24 Figure 17 Optical node segmentation 25 Figure 18 In house structures for transparent return p
19、ath transmission 26 Figure 19 Example of forward (862 MHz) and return path (65 MHz) network with operating levels for the drop and in home parts of the network . 28 Figure 20 Example of a block diagram of return path amplifier . 46 Figure 21 Commissioning of the forward path . 48 Figure 22 Commissio
20、ning of the return path amplifiers using the same method as on the forward path 49 Figure 23 Problem when commissioning return path amplifiers following the method used for downstream amplifiers (standard output levels) . 49 Figure 24 Unity gain method 50 Figure 25 Optical reverse path 50 PD CLC/TR
21、50083-10-1:2014CLC/TR 50083-10-1:2014 - 4 - Figure 26 Optical node with reverse transmitter 51 Figures in annexes Figure A.1 Typical spectrum of a return path. 54 Figure A.2 Noise funnelling 55 Figure A.3 Average noise level vs. the number of subscribers and the return path frequency 19 . 56 Figure
22、A.4 Simplified equivalent circuit of a drop cable . 56 Figure A.5 Screening effectiveness of a coaxial cable vs. frequency . 58 Figure A.6 Spectrogram of noise level vs. frequency and time (example) 60 Figure A.7 Maximum, minimum and average noise levels vs. frequency (example) 61 Figure A.8 Centile
23、 analysis of noise levels vs. frequency (example) 62 Figure A.9 Temporal evolution of the -10 dB(mV) threshold crossing occurrence (example) . 63 Figure A.10 Frequency evolution of the -10 dB(mV) threshold crossing occurrence (example) . 63 Figure A.11 Illustration of impulse noise measurement accor
24、ding to the method described in EN 60728-10 65 Figure A.12 Example for the use of the return path frequency range . 66 Figure A.13 Test set-up for CPD simulation 68 Figure A.14 Intermodulation products with 8 MHz spacing . 68 Figure A.15 Contact resistance as function of contact pressure . 69 Figure
25、 A.16 Upstream pass-band characterization . 70 Figure A.17 Set-up of test signals 71 Figure A.18 Test set-up for passive devices 71 Figure A.19 Test set-up for power passing devices 72 Figure A.20 Thermal cycle profile 72 Figure A.21 Spectral response with CPD in the return path 73 Tables Table 1 Su
26、mmary of in home return path losses . 30 Table 2 Calculation of return path versus temperature . 31 Table 3 Broadcasting allocations between 5 MHz and 42 MHz 38 Table 4 Amateur and Citizens Band allocations between 5 MHz and 42 MHz . 39 Table 5 DOCSIS/EuroDOCSIS symbol rates and channel widths 39 Ta
27、ble 6 Data carriers in the gaps between broadcasting bands . 40 Table 7 Data carriers in the gaps between broadcasting, amateur and CB bands . 40 Table 8 Available spectrum between 5 MHz and 65 MHz . 42 Table 9 Example of a 1,6 MHz wide channel plan up to 65 MHz (avoiding CPD products) . 43 Table 10
28、 Example of a 3,2 MHz wide channel plan up to 65 MHz 44 Table 11 Permitted radiation 0,3 MHz to 30 MHz (A-Deviation for Great Britain) . 45 Table 12 Permitted radiation 30 MHz to 68 MHz (A-Deviation for Great Britain) . 45 Table 13 Split frequencies used in Europe 47 Table 14 Alarm thresholds for up
29、stream monitoring (example). 53 Tables in Annexes Table A.1 European EMC standards applicable to home terminals 65 Table B.1 Null transport stream packet definition 74 Table C.1 ITU DWDM grid . 75 PD CLC/TR 50083-10-1:2014- 5 - CLC/TR 50083-10-1:2014 Foreword This document (CLC/TR 50083-10-1:2014) h
30、as been prepared by CLC/TC 209 “Cable networks for television signals, sound signals and interactive services“. This document supersedes CLC/TR 50083-10-1:2009. CLC/TR 50083-10-1:2014 includes the following significant technical changes with respect to CLC/TR 50083 10-1:2009: a) the introduction of
31、a new “General Scope“; b) the introduction of new upper frequency limit 85 MHz for return path as an option; c) the introduction of some new “Terms and definitions“ due to the new general scope and due to the introduction of the extended return path frequency range to 85 MHz; d) the deletion of Clau
32、se B.1 on “Noise power ratio“; e) the deletion of Clause B.2 on “10-tone measurement“; f) the deletion of Clause B.3 on “MER measurement“. EN 50083 is currently composed of the following parts: EN 50083-2, Cable networks for television signals, sound signals and interactive services Part 2: Electrom
33、agnetic compatibility for equipment; CLC/TR 50083-5-1, Cable networks for television signals, sound signals and interactive services Part 5-1: IP gateways and interfaces for headends; EN 50083-8, Cable networks for television signals, sound signals and interactive services Part 8: Electromagnetic co
34、mpatibility for networks; EN 50083-9, Cable networks for television signals, sound signals and interactive services Part 9: Interfaces for CATV/SMATV headends and similar professional equipment for DVB/MPEG-2 transport streams; EN 50083-10, Cable networks for television signals, sound signals and in
35、teractive services Part 10: System performance for return paths; CLC/TR 50083-10-1, Cable networks for television signals, sound signals and interactive services Part 10-1: Guidelines for the implementation of return paths in cable networks the present document. Attention is drawn to the possibility
36、 that some of the elements of this document may be the subject of patent rights. CENELEC and/or CEN shall not be held responsible for identifying any or all such patent rights. _ PD CLC/TR 50083-10-1:2014CLC/TR 50083-10-1:2014 - 6 - 1 Scope 1.1 General Standards and other deliverables of the EN 5008
37、3 and EN 60728 series deal with cable networks including equipment and associated methods of measurement for headend reception, processing and distribution of television and sound signals and for processing, interfacing and transmitting all kinds of data signals for interactive services using all ap
38、plicable transmission media. These signals are typically transmitted in networks by frequency-multiplexing techniques. This includes for instance: regional and local broadband cable networks, extended satellite and terrestrial television distribution networks and systems, individual satellite and te
39、rrestrial television receiving systems and all kinds of equipment, systems and installations used in such cable networks, distribution and receiving systems. The extent of this standardization work is from the antennas and/or special signal source inputs to the headend or other interface points to t
40、he network up to the terminal input of the customer premises equipment. The standardization work will consider coexistence with users of the RF spectrum in wired and wireless transmission systems. The standardization of any user terminals (i.e. tuners, receivers, decoders, multimedia terminals etc.)
41、 as well as of any coaxial, balanced and optical cables and accessories thereof is excluded. 1.2 Specific scope of this Technical Report This document is intended to provide guidance to network designers on the issues which should be addressed when considering the design of return paths for regional
42、 or local broadband networks. Items such as return path architecture Third Generation Transmission Systems for Interactive Cable Television Services IP Cable Modems ETSI ES 201 488 series, Access and Terminals (AT); Data Over Cable Systems ETSI ES 202 488 series, Access and Terminals (AT); Second Ge
43、neration Transmission Systems for Interactive Cable Television Services IP Cable Modems 3 Terms, definitions, symbols and abbreviations 3.1 Terms and definitions For the purposes of this document, the following terms and definitions apply. NOTE As far as possible the available terms and definitions
44、are taken from IEC 60050 series and are repeated below. The relevant IEV-numbers or other references are given in rectangular brackets after the definition text. 3.1.1 CATV networks regional and local broadband cable networks designed to provide sound and television signals as well as signals for in
45、teractive services to a regional or local area Note 1 to entry: This was originally defined as Community Antenna Television networks. 3.1.2 common path distortion intermodulation distortion of downstream signals, mainly due to nonlinearities found at metallic junctions Note 1 to entry: The distortio
46、ns are manifest as a series of beats (caused by analogue downstream channels) or a band(s) of noise (caused by digital downstream channels) most noticeably in the upstream path. CPD may also be present in the downstream path, but since it adds with other downstream distortions (i.e. CTB and CSO), ca
47、used by active components, it is difficult to differentiate between the two. The nonlinear behaviour found at passive junctions may be due to a number of reasons including corrosion, typically from exposure to the elements, dissimilar metals, contact pressure, and junctions involving connectors cont
48、aminated with carbonaceous materials. 3.1.3 downstream direction direction of signal flow in a cable network from the headend or any other central point (node) of a cable network towards the subscriber SOURCE: EN 60728-10:2014, modified 3.1.4 extended satellite television distribution network or sys
49、tem distribution network or system designed to provide sound and television signals received by satellite receiving antenna to households in one or more buildings Note 1 to entry: This kind of network or system could be eventually combined with terrestrial antennas for the additional reception of TV and/or radio signals via terrestrial networks. Note 2 to entry: This kind of netw
