SIST-TP CLC/TR 50083-10-1:2009

Cable networks for television signals, sound signals and interactive services - Part 10-1: Guidelines for the implementation of return paths in cable networks

This document is intended to provide guidance to network designers on the issues which should be
addressed, when considering the design of a CATV (HFC) return path.Items such as return path architecture & design, channel performance, channel planning & sources of interference, measurements, segmentation & 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 CATV/HFC return path.

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

Kabelska omrežja za televizijske in zvokovne signale ter interaktivne elemente - 10-1. del: Smernice za uporabo povratnih poti v kabelskih omrežjih

General Information

• Status: Withdrawn
• Publication Date: 05-Mar-2009
• Withdrawal Date: 31-Aug-2014
• ICS: 33.060.40 - Cabled distribution systems
• Technical Committee: AVM - Audio, video and multimedia systems and equipment
• Current Stage: 9900 - Withdrawal (Adopted Project)
• Start Date: 28-Aug-2014
• Due Date: 20-Sep-2014
• Completion Date: 01-Sep-2014
• Ref Project: CLC/TR 50083-10-1:2009 - Cable networks for television signals, sound signals and interactive services - Part 10-1: Guidelines for the implementation of return paths in cable networks

Relations

• Replaced By: SIST-TP CLC/TR 50083-10-1:2014 - Cable networks for television signals, sound signals and interactive services -- Part 10-1: Guidelines for the implementation of return paths in cable networks
• Effective Date: 01-Oct-2014

Standards Content (Sample)

SLOVENSKI STANDARD
SIST-TP CLC/TR 50083-10-1:2009
01-april-2009
Kabelska omrežja za televizijske in zvokovne signale ter interaktivne elemente - 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 50083-10-1:2009
ICS:
33.060.40 Kabelski razdelilni sistemi Cabled distribution systems
SIST-TP CLC/TR 50083-10-1:2009 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST-TP CLC/TR 50083-10-1:2009

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SIST-TP CLC/TR 50083-10-1:2009

TECHNICAL REPORT
CLC/TR 50083-10-1

RAPPORT TECHNIQUE
February 2009
TECHNISCHER BERICHT

ICS 33.060.40


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







This Technical Report was approved by CENELEC on 2008-12-05.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Cyprus, the
Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.





CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung

Central Secretariat: avenue Marnix 17, B - 1000 Brussels


© 2009 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. CLC/TR 50083-10-1:2009 E

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SIST-TP CLC/TR 50083-10-1:2009
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Foreword
This Technical Report was prepared by the Technical Committee CENELEC TC 209, Cable networks for
television signals, sound signals and interactive services.
The text of the draft was submitted to the vote in accordance with the Internal Regulations, Part 2,
Subclause 11.4.3.3 (simple majority) and was approved by CENELEC as CLC/TR 50083-10-1 on
2008-12-05.
__________

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Contents
1 Scope . 7
1.1 General. 7
1.2 Specific scope of this Technical Report . 7
2 Normative references . 7
3 Terms, definitions, symbols and abbreviations . 8
3.1 Terms and definitions . 9
3.2 Symbols .11
3.3 Abbreviations .12
4 Network architecture .14
4.1 HFC architecture .14
4.2 Upgrade alternatives .16
4.3 Active or passive return path .26
4.4 In building network .26
4.5 In home network .27
5 Network design .28
5.1 Considerations .28
5.2 Return path loss, path loss difference and return path slope .28
5.3 Noise and nonlinearity, optimising signal levels .32
5.4 Isolation between outlets.35
5.5 Equalisation and filtering in return paths .35
6 Channel planning .38
6.1 Purpose of this section .38
6.2 Introduction .38
6.3 Summary .38
6.4 Considerations for channel planning .39
6.5 Common path distortion products .44
6.6 European upstream bandwidths .44
6.7 Channel width .44
6.8 QPSK/16QAM operation and channel widths .44
6.9 Available return path spectrum (Table 8) .45
6.10 Channel plans .46
6.11 Network radiation .48
7 Equipment for return path implementation .48
7.1 General.48
7.2 Return path amplifiers .48
7.3 Equipment for fibre optic return links .51
8 Installation and maintenance .51
8.1 Signal level adjustment .51
8.2 Monitoring and measurements .56

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Annex A (informative) Interference on return path .59
A.1 Multiple interference .59
A.2 Impulse interference .69
A.3 Interference from home terminals .71
A.4 Hum modulation .71
A.5 Common path distortion (CPD) .72
Annex B (informative) Methods of measurement .82
B.1 Noise power ratio (NPR) measurement on return path .82
B.2 10-Tone measurement .88
B.3 Modulation error ratio (MER) measurement on return path .91
B.4 Null packet and PRBS definitions .93
Annex C (informative) ITU DWDM grid .95
Bibliography .97
Figures
Figure 1 – Typical HFC topology . 14
Figure 2 – Regional network . 15
Figure 3 – Trunk-and-distribution architecture using only coaxial equipment . 16
Figure 4 – HFC system . 17
Figure 5 – Generic diagram showing the mapping of nodes and CMTS(s) to segments . 18
Figure 6 – Segment comprising a single CMTS to six optical nodes . 18
Figure 7 – Spectrum allocation bandwidth . 19
Figure 8 – Basic node architecture . 20
Figure 9 – Re-arranged feeds (two CMTS serving four nodes) . 21
Figure 10 – Optical node with frequency stacking . 22
Figure 11 – Divided node . 22
Figure 12 – Return path segmentation . 23
Figure 13 – Division of the node areas using additional fibres. . 23
Figure 14 – DWDM (CWDM) return path transmission . 24
Figure 15 – Digital return technology basic concept . 25
Figure 16 – Two return paths multiplexed to the transmission stream . 25
Figure 17 – Optical node segmentation . 26
Figure 18 – In house structures for transparent return path transmission . 27
Figure 19 – Example of forward and return path network with operating levels for the drop and
in home parts of the network . 29
Figure 20 – Example of a block diagram of return path amplifier. 49
Figure 21 – Commissioning of the forward path. 52
Figure 22 – Commissioning of the return path amplifiers using the same method as on the
forward path . 52
Figure 23 – Problem when commissioning return path amplifiers following the method used for
downstream amplifiers (standard output levels) . 53
Figure 24 – Unity gain method . 54
Figure 25 – Optical reverse path . 54

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Figure 26 – Optical node with reverse transmitter . 55
Figures in annexes
Figure A.1 – Typical spectrum of a return path . 59
Figure A.2 – Noise funnelling . 60
Figure A.3 – Average noise level vs. the number of subscribers and the return path frequency [6] . 61
Figure A.4 – Simplified equivalent circuit of a drop cable . 61
Figure A.5 – Screening effectiveness of a coaxial cable vs. frequency . 63
Figure A.6 – Spectrogram of noise level vs. frequency and time (example) . 65
Figure A.7 – Maximum, minimum and average noise levels vs. frequency (example) . 66
Figure A.8 – Centile analysis of noise levels vs. frequency (example) . 67
Figure A.9 – Temporal evolution of the -10 dB(mV) threshold crossing occurrence (example) . 68
Figure A.10 – Frequency evolution of the -10 dB(mV) threshold crossing occurrence (example) . 68
Figure A.11 – Illustration of impulse noise measurement according to the method described in
  EN 60728-10 . 70
Figure A.12 – Example for the use of the return path frequency range . 72
Figure A.13 – Test set-up for CPD simulation . 74
Figure A.14 – Intermodulation products with 8 MHz spacing . 75
Figure A.15 – Contact resistance as function of contact pressure . 76
Figure A.16 – Upstream pass-band characterisation . 77
Figure A.17 – Set-up of test signals . 78
Figure A.18 – Test set-up for passive devices . 78
Figure A.19 – Test set-up for power passing devices . 79
Figure A.20 – Thermal cycle profile . 79
Figure A.21 – Spectral response with CPD in the return path . 80
Figure B.1 – Band-pass and band-stop filters response . 82
Figure B.2 – NPR test set up . 83
Figure B.3 – NPR versus RF power density applied at input of optical transmitter
and determination of OMI 100 % . 84
Figure B.4 – Example of the frequency response of the optional band-pass filter. 85
Figure B.5 – Correction factor versus level difference . 86
Figure B.6 – Example of NPR dynamic range. 88
Figure B.7 – Dynamic Range (dB) plotted versus NPR (dB) . 88
Figure B.8 – Alternative NPR measurement principle . 89
Figure B.9 – Relationship between classical NPR method and multi-tone method . 90
Figure B.10 – Test set-up for Modulation Error Ratio (MER) measurement . 91
Figure B.11 – Example of constellation diagram for a 64QAM modulation format . 92
Tables
Table 1 – Summary of in home return path losses . 31
Table 2 – Calculation of return path versus temperature . 32
Table 3 – Broadcasting allocations between 5 MHz and 42 MHz . 41
Table 4 – Amateur and Citizens Band allocations between 5 MHz and 42 MHz . 41
Table 5 – DOCSIS/EuroDOCSIS symbol rates and channel widths . 42
Table 6 – Data carriers in the gaps between broadcasting bands . 43

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Table 7 – Data carriers in the gaps between broadcasting, amateur and CB bands . 43
Table 8 – Available spectrum between 5 MHz and 65 MHz . 45
Table 9 – Example of a 1,6 MHz wide channel plan (avoiding CPD products) . 46
Table 10 – Example of a 3,2 MHz wide channel plan . 47
Table 11 – Permitted radiation 0,3 MHz to 30 MHz (A-Deviation for Great Britain). 48
Table 12 – Permitted radiation 30 MHz to 68 MHz (A-Deviation for Great Britain). 48
Table 13 – Split frequencies used in Europe . 50
Table 14 – Alarm thresholds for upstream monitoring (example) . 58
Tables in annexes
Table A.1 – European EMC standards applicable to home terminals . 71
Table B.1 – Band-stop filter notch frequencies . 82
Table B.2 – Noise correction factor . 86
Table B.3 – Null transport stream packet definition . 93
Table C.1 – ITU DWDM grid. 95

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1 Scope
1.1 General
Standards 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
signals, sound signals and their associated data signals and for processing, interfacing and
transmitting all kinds of signals for interactive services using all applicable transmission media.
This includes
1)
• CATV -networks;
• MATV-networks and SMATV-networks;
• individual receiving networks;
and all kinds of equipment, systems and installations installed in such networks.
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.
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 a CATV (HFC) return path.
Items such as return path architecture & design, channel performance, channel planning & sources
of interference, measurements, segmentation & 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 CATV/HFC
return path.
2 Normative references
The following referenced documents are indispensable for the application of this document. For
dated references, only the edition cited applies. For undated references, the latest edition of the
referenced document (including any amendments) applies.
EN 50083-2 Cable networks for television signals, sound signals and interactive services -
Part 2: Electromagnetic compatibility for equipment
EN 50083-8 Cable networks for television signals, sound signals and interactive services -
Part 8: Electromagnetic compatibility for networks
EN 55013 Sound and television broadcast receivers and associated equipment - Radio
+ A1 disturbance characteristics - Limits and methods of measurement
+ A2 (CISPR 13, mod. + A1 + A2)
EN 55020 Sound and television broadcast receivers and associated equipment - Immunity
characteristics - Limits and methods of measurement (CISPR 20)
———————
1)

This word encompasses the HFC networks used nowadays to provide telecommunications services, voice, data, audio and video,

both broadcast and narrowcast.

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EN 55022 Information technology equipment - Radio disturbance characteristics - Limits and
+ A1 methods of measurement (CISPR 22, mod. + A1)
EN 55024 Information technology equipment - Immunity characteristics - Limits and methods of
+ A1 measurement (CISPR 24, mod. + A1 + A2)
+ A2
EN 60728-1 Cable networks for television signals, sound signals and interactive services -
Part 1: System performance (IEC 60728-1)
EN 60728-3 Cable networks for television signals, sound signals and interactive services -
Part 3: Active wideband equipment for coaxial 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)
EN 60728-10 Cable networks for television signals, sound signals and interactive services -
Part 10: System performance for return paths (IEC 60728-10)
EN 61280-2-2 Fibre optic communication subsystem test procedures -
Part 2-2: Digital systems - Optical eye pattern, waveform and extinction ratio
measurement (IEC 61280-2-2)
ETSI EN 300 386 Electromagnetic compatibility and Radio spectrum Matters (ERM);
Telecommunication network equipment; Electromagnetic Compatibility (EMC)
requirements
ETSI ES 201 488-1 Access and Terminals (AT); Data Over Cable Systems;
Part 1: General
ETSI ES 201 488-2 Access and Terminals (AT); Data Over Cable Systems;
Part 2: Radio Frequency Interface Specification
ETSI ES 202 488-1 Access and Terminals (AT); Second Generation Transmission Systems for
Interactive Cable Television Services - IP Cable Modems;
Part 1: General
ETSI ES 202 488-2 Access and Terminals (AT); Second Generation Transmission Systems for
Interactive Cable Television Services - IP Cable Modems;
Part 2: Radio frequency interface specification
ETSI ETS 300 800 Digital Video Broadcasting (DVB);Interaction channel for Cable TV distribution
systems (CATV)
IEC 60050 International Electrotechnical Vocabulary (IEV)
IEC 60617 database Graphical symbols for diagrams
IEC/TR 61931 Fibre optic - Terminology
ISO/IEC 13818-1 Information technology - Generic coding of moving pictures and associated audio
information: Systems

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3 Terms, definitions, symbols and abbreviations
3.1 Terms and definitions
For the purposes of this technical report, the terms and definitions listed hereafter apply. 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
common path distortion
intermodulation distortion of downstream signals, mainly due to nonlinearities found at metallic junctions. 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
3.1.2
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
[EN 60728-10, modified]
3.1.3
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
[EN 60728-10, modified]
3.1.4
gateway
functional unit that connects two computer networks with different network architectures
EXAMPLES – LAN gateway, mail gateway
NOTE The computer networks may be either local area networks, wide area networks or other types of networks.
[IEV 732-01-16]
3.1.5
headend
assembly of equipment feeding signals into a cable network from local or external sources, including
equipment for reception and signal processing
[IEV 723-09-11, modified]
NOTE The headend may, for example, comprise antenna amplifiers, frequency converters, combiners, separators and generators.
3.1.6
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)
3.1.7
hybrid fibre coaxial network
HFC network
cable network which comprises optical equipment and cables and coaxial equipment and cables in different
parts
[EN 60728-10]

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3.1.8
ingress noise
noise which is caused by electromagnetic interference into cable networks. Its power decreases with
increasing frequency. It is permanently present but slowly varies in its intensity as a function of time
[EN 60728-10]
3.1.9
(network) segment
part of a cable network comprising a set of functions and/or a specific extent of the complete cable network
[EN 60728-10]
3.1.10
network termination unit
NTU
equipment for access to
...