CLC/TR 50083-10-1:2014

SLOVENSKI STANDARD
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
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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

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

- 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 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

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
...