1、 International Telecommunication Union ITU-T J.185TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (06/2012) SERIES J: CABLE NETWORKS AND TRANSMISSION OF TELEVISION, SOUND PROGRAMME AND OTHER MULTIMEDIA SIGNALS Digital transmission of television signals Transmission equipment for transferring multi-c
2、hannel television signals over optical access networks by frequency modulation conversion Recommendation ITU-T J.185 Rec. ITU-T J.185 (06/2012) i Recommendation ITU-T J.185 Transmission equipment for transferring multi-channel television signals over optical access networks by frequency modulation c
3、onversion Summary Recommendation ITU-T J.185 describes a transmission method for transferring multi-channel television signals over optical access networks. ITU-T J.185 transmission equipment is capable of realizing multi-channel AM-VSB, 64-QAM, and 256-QAM video signal transmission through the use
4、of frequency modulation conversion. History Edition Recommendation Approval Study Group 1.0 ITU-T J.185 2002-02-13 9 2.0 ITU-T J.185 2012-06-13 9 ii Rec. ITU-T J.185 (06/2012) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommun
5、ications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunic
6、ations on a worldwide basis. The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. The approval of ITU-T Recommendations is covered by the procedur
7、e laid down in WTSA Resolution 1. In some areas of information technology which fall within ITU-Ts purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. NOTE In this Recommendation, the expression “Administration“ is used for conciseness to indicate both a telecomm
8、unication administration and a recognized operating agency. Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these
9、 mandatory provisions are met. The words “shall“ or some other obligatory language such as “must“ and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. INTELLECTUAL PROPERTY RIGHTS ITU d
10、raws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members
11、 or others outside of the Recommendation development process. As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not r
12、epresent the latest information and are therefore strongly urged to consult the TSB patent database at http:/www.itu.int/ITU-T/ipr/. ITU 2012 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. Rec. ITU-T J.185 (06
13、/2012) iii Table of Contents Page 1 Scope 1 2 References. 1 3 Definitions 2 3.1 Terms defined elsewhere 2 3.2 Terms defined in this Recommendation . 2 4 Abbreviations and acronyms 2 5 Conventions 3 6 System description 4 7 Performance of analogue and/or digital video transmission system 4 7.1 Specif
14、ied transmission quality for analogue video signal 4 7.2 Specified transmission quality for digital video signal 4 Annex A Multi-channel video broadcast system over optical access network: system A 6 A.1 System description 6 A.2 TX . 8 A.3 V-OLT 11 A.4 V-ONT 12 Annex B Multi-channel video broadcast
15、system with cascaded V-OLTs: system B . 14 B.1 System description 14 B.2 TX . 16 B.3 V-OLT 19 B.4 V-ONT 20 Appendix I FM frequency deviation and minimum received optical power for CATV band of 47 to 864 MHz . 23 Appendix II FM frequency deviation and minimum received optical power for CATV band of 4
16、7 to 2100 MHz . 25 Bibliography. 27 Rec. ITU-T J.185 (06/2012) 1 Recommendation ITU-T J.185 Transmission equipment for transferring multi-channel television signals over optical access networks by frequency modulation conversion 1 Scope This Recommendation describes a method of transmitting multi-ch
17、annel television signals over an optical access network that utilizes frequency modulation (FM) conversion. In this FM transmission system, multi-channel frequency-division multiplexing (FDM) television signals are simultaneously converted into one single wideband FM signal. This FM signal is then t
18、ransmitted through the optical access network by using the intensity modulation technique. The video-optical network terminal (V-ONT) at the customer premises converts the received single FM signal into the original multi-channel FDM video signals, i.e., coaxial cable television (CATV) signals. The
19、interface for this FM transmission system is the same as that of the amplitude modulation sub-carrier multiplexing (AM-SCM) system. Therefore, the FM transmission system can replace the AM-SCM system. The FM transmission system is required to have an FM converter, i.e., frequency modulator and frequ
20、ency demodulator, in addition to the AM-SCM transmission systems equipment. However, it has a better efficiency than the AM-SCM transmission system against the noise deterioration caused by optical transmission/splitter loss and optical reflections. In the SCM technique, the main carrier is the opti
21、cal frequency signal carrier; the sub-carriers transfer the electrically multiplexed FDM video signals in the optical sideband. This system can be added to the ITU-T G.983.1 series B-PON system by using ITU-T G.983.3 wavelength-division multiplexing (WDM) technology, to the ITU-T G.984 series G-PON
22、system and ITU-T G.987 series XG-PON system by using ITU-T G.984.5 WDM technology, and to the IEEE 802.3ah/802.3av EPON systems. This integration would allow the system to offer broadcast services and also data and voice communication services over the same optical access network. By using the bidir
23、ectional data PON system, upstream signals, e.g., control functionality and upstream data indicating the users requirements, can be transmitted as well. 2 References The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisio
24、ns of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations
25、and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. ITU-T J.83 Recommendation ITU-T J.83 (2007), Digital mult
26、i-programme systems for television, sound and data services for cable distribution. ITU-R BO.1408-1 Recommendation ITU-R BO.1408-1 (2002), Transmission system for advanced multimedia services provided by integrated services digital broadcasting in a broadcasting-satellite channel. ITU-R BT.1306-3 Re
27、commendation ITU-R BT.1306-3 (2006), Error-correction, data framing, modulation and emission methods for digital terrestrial television broadcasting. IEC 60728-1 IEC 60728-1 (2007), Cable networks for television signals, sound signals and interactive services-Part 1; System performance of forward pa
28、ths. 2 Rec. ITU-T J.185 (06/2012) 3 Definitions 3.1 Terms defined elsewhere This Recommendation uses the following terms defined elsewhere: 3.1.1 access network b-ITU-T K.44: That part of the overall telecommunication network that is located between a telecommunication centre and the customer premis
29、es building. 3.1.2 carrier b-ITU-R V.662-3: An oscillation or wave, usually periodic, some characteristic of which is intended to be constrained by modulation to follow the values of a signal or of another oscillation. 3.1.3 sub-carrier multiplexing b-ITU-T G.982: Multiplexing multiple electrical fr
30、equencies onto a single fibre at a single wavelength to provide an individual frequency to each multipoint-to-point path. 3.1.4 trunk network b-ITU-T K.44: That part of the telecommunication system that is located between two telecommunication centres and that provides the communication between the
31、centres. 3.2 Terms defined in this Recommendation None. 4 Abbreviations and acronyms This Recommendation uses the following abbreviations and acronyms: AC Alternating Current AM-SCM Amplitude Modulation Sub-Carrier Multiplexing AM-VSB Amplitude Modulation Vestigial Sideband AMP/BRC-U Amplifier and B
32、ranch Unit APD Avalanche Photo Diode BER Bit Error Rate B-PON Broadband Passive Optical Network CATV Cable Television CNR Carrier-to-Noise Ratio CSO Composite Second Order distortion CTB Composite Triple Beat distortion DC Direct Current DI Discrete Interference D/U Desired-to-Undesired signal ratio
33、 E/O Electrical to Optical converter EPON Ethernet Passive Optical Network FEC Forward Error Correction FDM Frequency-Division Multiplexing FM Frequency Modulation G-PON Gigabit Passive Optical Network Rec. ITU-T J.185 (06/2012) 3 IF Intermediate Frequency IM Intensity Modulated ISDB-T Integrated Se
34、rvices Digital Broadcasting Terrestrial MER Modulation Error Rate NTSC National Television System Committee OFDM Orthogonal Frequency Division Multiplexing OMI Optical Modulation Index PAL Phase Alternating Line PIN-PD p-i-n Photo Diode PON Passive Optical Network PSK Phase Shift Keying QAM Quadratu
35、re Amplitude Modulation QPSK Quadrature Phase Shift Keying RA Repeater Amplifier RF Radio Frequency RIN Relative Intensity Noise RMS Root Mean Square SBS Stimulated Brillouin Scattering SCM Sub-Carrier Multiplexing SECAM Squentiel couleur mmoire STB Set-Top Box TC8PSK Trellis-Coded Eight Phase Shift
36、 Keying TX Transmitter V-OLT Video-Optical Line Terminal V-ONT Video-Optical Network Terminal VSWR Voltage Standing Wave Ratio WDM Wavelength-Division Multiplexing XG-PON 10-Gigabit Passive Optical Network XM Cross Modulation distortion 5 Conventions In this Recommendation: The keywords “is required
37、 to“ indicate a requirement which must be strictly followed and from which no deviation is permitted, if conformance to this Recommendation is to be claimed. The keywords “is recommended“ indicate a requirement which is recommended but which is not absolutely required. Thus, this requirement need no
38、t be present to claim conformance. The keywords “can optionally“ indicate an optional requirement which is permissible, without implying any sense of being recommended. This term is not intended to imply that the vendors 4 Rec. ITU-T J.185 (06/2012) implementation must provide the option, and the fe
39、ature can be optionally enabled by the network operator/service provider. Rather, it means the vendor may optionally provide the feature and still claim conformance with this Recommendation. 6 System description Figure 1 is a system description of multi-channel television signals transmission employ
40、ing frequency modulation (FM) conversion. Video signal from the headend is input to the transmitter (TX) and E/O converted, and then transmitted to the video-optical network terminal (V-ONT) via the video-optical line terminal (V-OLT). For actual installations, this system covers not only the optica
41、l access network, but also the optical trunk network with cascaded V-OLTs. Figure 1 System configuration of an FM-converted multi-channel television signal transmission system 7 Performance of analogue and/or digital video transmission system 7.1 Specified transmission quality for analogue video sig
42、nal Table 1 shows specified transmission quality for the amplitude modulation vestigial sideband (AM-VSB) analogue video signal. The carrier power of the analogue video signal is measured as the peak envelope power. Table 1 Specified transmission quality for analogue video signal TV system M-system
43、NTSC B, G-system PAL L-system SECAM Noise bandwidth 4.0 MHz 4.75 MHz 5.0 MHz CNR 43 dB (Note) 44 dB 44 dB CSO 53 dB 52 dB 52 dB CTB 54 dB 52 dB 52 dB XM 46 dB 46 dB 46 dB DI 57 dB (Note) Not specified Not specified NOTE Refer to IEC 60728-1. 7.2 Specified transmission quality for digital video signa
44、l Tables 2 and 3 show specified transmission quality for the digital video signal. TX V-OLT V-ONTHeadendRec. ITU-T J.185 (06/2012) 5 Table 2 Specified transmission quality for the digital video signal 64-QAM signal 256-QAM signal Annex A of ITU-T J.83 Annex B of ITU-T J.83 Annex A of ITU-T J.83 Anne
45、x B of ITU-T J.83 Annex A of ITU-T J.83 Symbol rate Not specified 5.057 Mbaud 5.274 Mbaud 5.36 Mbaud 5.274 Mbaud CNR (Note 4) 27 dB (Notes 1, 2) 27 dB (Notes 1, 2) 26 dB (Note 2) 40 dB (Notes 1, 2) 34 dB (Notes 1, 2) MER Not specified Not specified Not specified 32 dB (Note 1) Not specified CSO/CTB
46、Not specified Not specified 39 dB (Note 3) 47 dB (Note 3) 45 dB (Note 3) Pre-FEC BER Not specified 1 105Not specified 1 109Not specified Post-FEC BER Not specified 1 1012Not specified 1 1015Not specified NOTE 1 This value includes the simultaneous presence of all impairments in the 6-MHz channel ban
47、dwidth, including composite distortion or other discrete interference. NOTE 2 The carrier power is measured as the average root mean square (RMS) signal power. NOTE 3 These undesired signals are caused by interference among AM-VSB channels. NOTE 4 Noise bandwidth is defined by symbol rate.Table 3 Sp
48、ecified transmission quality for the digital video signal QPSK signal (Note 5) TC8PSK signal (Note 5) ISDB-T (Note 6) Noise bandwidth 28.86 MHz 28.86 MHz 5.6 MHz CNR (Note 4) 8 dB (Notes 1, 2) 11 dB (Notes 1, 2) 24 dB (Notes 1, 2) CSO/CTB Not specified Not specified 45 dB (Note 3) NOTE 1 This value
49、includes the simultaneous presence of all impairments in the 6-MHz channel bandwidth, including composite distortion or other discrete interference. NOTE 2 The carrier power is measured as the average RMS signal power. NOTE 3 These undesired signals are caused by interference among AM-VSB channels. NOTE 4 Noise bandwidth is defined by symbol rate. NOTE 5 Refer to ITU-R BO.1408-1
