SIST-TP CLC/TR 50083-10-1:2014

SLOVENSKI STANDARD
SIST-TP CLC/TR 50083-10-1:2014
01-oktober-2014
1DGRPHãþD
SIST-TP CLC/TR 50083-10-1:2009
Kabelska omrežja za televizijske signale, zvokovne signale in interaktivne storitve
- 10-1. del: Smernice za uporabo povratnih poti v kabelskih omrežjih
Cable networks for television signals, sound signals and interactive services -- Part 10-1:
Guidelines for the implementation of return paths in cable networks
Kabelnetze für Fernsehsignale, Tonsignale und interaktive Dienste -- Teil 10-1: Leitfaden
für die Einrichtung von Rückkanälen in Kabelnetzen
Réseaux de distribution par câbles pour signaux de télévision, signaux de radiodiffusion
sonore et services interactifs -- Partie 10-1: Lignes directrices relatives à la mise en
oeuvre de la voie de retour dans les réseaux câblés
Ta slovenski standard je istoveten z: CLC/TR 50083-10-1:2014
ICS:
33.060.40 Kabelski razdelilni sistemi Cabled distribution systems
SIST-TP CLC/TR 50083-10-1:2014 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST-TP CLC/TR 50083-10-1:2014


TECHNICAL REPORT CLC/TR 50083-10-1

RAPPORT TECHNIQUE

TECHNISCHER BERICHT
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 return paths in cable networks
Réseaux de distribution par câbles pour signaux de Kabelnetze für Fernsehsignale, Tonsignale und interaktive
télévision, signaux de radiodiffusion sonore et services Dienste - Teil 10-1: Leitfaden für die Einrichtung von
interactifs - Partie 10-1: Lignes directrices relatives à la Rückkanälen in Kabelnetzen
mise en oeuvre de la voie de retour dans les réseaux
câblés


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, Former 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 Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für 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. CLC/TR 50083-10-1:2014 E

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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
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 slope . 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 distortion 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 path amplifiers . 45
8 Installation and maintenance . 48

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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 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 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 nodes . 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 areas 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 path 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 — Commissioning 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

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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 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 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 according 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 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 — Summary 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
Table 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 — 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 upstream 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

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Foreword
This document (CLC/TR 50083-10-1:2014) has 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 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 Clause 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:
Electromagnetic 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 compatibility 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 interactive 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 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.
__________

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1 Scope
1.1 General
Standards and other deliverables of the EN 50083 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 applicable 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 terrestrial 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 the 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.) 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 or local broadband networks.
Items such as return path architecture & design, channel performance, channel planning and sources of
interference, measurements, segmentation and re-segmentation, in home networks, distortion and
commissioning are included. This document is not intended as a design reference but provides details which
need to be addressed on individual issues relating to the design of the return path for a regional or local
broadband network.
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 undated references,
the latest edition of the referenced document (including any amendments) applies.
EN 60728-1:2008, Cable networks for television signals, sound signals and interactive services — Part 1:
System performance of forward paths (IEC 60728-1:2007)
EN 60728-3, Cable networks for television signals, sound signals and interactive services — Part 3: Active
wideband equipment for cable networks (IEC 60728-3)
EN 60728-4, Cable networks for television signals, sound signals and interactive services — Part 4: Passive
wideband equipment for coaxial cable networks (IEC 60728-4)
EN 60728-5, Cable networks for television signals, sound signals and interactive services — Part 5: Headend
equipment (IEC 60728-5)
EN 60728-6, Cable networks for television signals, sound signals and interactive services — Part 6: Optical
equipment (IEC 60728-6)

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EN 60728-10:2014, Cable networks for television signals, sound signals and interactive services — Part 10:
System performance for return paths (IEC 60728-10:2014)
ETSI EN 302 878 series, Access, Terminals, Transmission and Multiplexing (ATTM); 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 Generation 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 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 interactive 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 distortions 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), caused 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 contaminated 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 system
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 network or system could also carry control signals for satellite switched systems or other signals for
special transmission systems (e.g. MoCA or WiFi) in the return path direction.
3.1.5
extended terrestrial television distribution network or system
distribution network or system designed to provide sound and television signals received by terrestrial
receiving antenna to households in one or more buildings
Note 1 to entry:  This kind of network or system could be eventually combined with a satellite antenna for the additional reception of
TV and/or radio signals via satellite networks.
Note 2 to entry: This kind of network or system could also carry other signals for special transmission systems (e.g. MoCA or WiFi) in
the return path direction.

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3.1.6
forward path (downstream)
physical part of a cable network by which signals are distributed in the downstream direction from the
headend or any other central point (node) of a cable network towards the subscriber
[SOURCE: EN 60728-10:2014, modified]
3.1.7
gateway
functional unit that connects two computer networks with different network architectures
EXAMPLES LAN gateway, mail gateway.
Note 1 to entry:  The computer networks may be either local area networks, wide area networks or other types of networks.
[SOURCE: IEC 60050, IEV 732-01-16 – definition altered and original Note 2 turned into the present
"EXAMPLES" paragraph]
3.1.8
headend
assembly of equipment feeding signals into a cable network from local or external sources, including
equipment for reception and signal processing
[SOURCE: IEC 60050, IEV 723-09-11, modified – definition altered]
Note 1 to entry:  The headend may, for example, comprise antenna amplifiers, frequency converters, combiners, separators and
generators.
3.1.9
hub
local area distribution point for the insertion and recovery of two-way narrowcast signals such as
DOCSIS/EuroDOCSIS with broadcast transmissions from the headend in the RF domain (frequency
multiplexing)
3.1.10
hybrid fibre
...