Field Trial of Optical Fibre Cable-TV System Optical Fibre System for ...

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Optical Fibre System for Digital Cable-TV Transmission, ZAV 280/4 Gerhard Gobi and Sten Jacobson ZAV 280/4 is a system for digital transmission of television and stereo sound programs over optical fibre. It has been designed for use in large cable-TV distribution networks, at the upper network levels. The digital transmission ensures high picture and sound quality regardless of the size of the network. ZAV 280/4 was developed by Ericsson in collaboration with the Swedish Telecommunications Administration and the first field trial took place in a suburb of Stockholm (Skarpnäck). The authors describe the design and function of the system and also discuss the network structure. UDC 535.394:621.397.74 cable television optical links digital communication systems System ZAV 280/4 has been developed to provide high-quality transmission of picture and audio signals in large and medium-sized cable-TV networks. The high quality is ensured by means of digital transmission over optical fibre. In a cable-TV network, fig. 1, ZAV 280/4 is used at the trunk and primary network levels, while conventional analog coaxial cable systems are used at the secondary and on premises network levels. Such a network structure is sometimes called a hybrid network because different transmission systems are used in different parts of the network. As can be seen from the system designation, ZAV 280/4, the system data rate is 280 Mbit/s, which permits the transmission of four digital video signals and 16 audio channels, corresponding to four television programs and four to six stereo audio programs (depending on whether the television programs have stereo or mono sound). The system also has a data transmission capacity of 2x640 kbit/s. ZAV 280/4 has a modular structure based on the standard transmission rate of 139.264 Mbit/s, both as regards the electrical and the mechanical construction. ZAV 280/4 can therefore be used as encoding equipment with either 140 or 565 Mbit/s line systems. The system is then equipped with CMI adapters instead of optical transmitters and receivers in order to provide a standard CCITT D4 interface. The system offers optical transmission over multi-mode fibres at a wavelength of 850 nm or over single-mode fibres at 1300 nm, with a repeater span of 5-7 km (with a fibre bandwidth of 500- 800 MHz km) or 25-30 km respectively. Active (electrical) and passive (optical) branching equipment and regenerators are also available to ensure flexibility as regards network configuration. The basic version of ZAV 280/4 comprises two 19" magazines having a Hepeater and active branching Trunk network-^ Primary network Base^p band ^7 Local centre Repeater Trunk line wn
GERHARD GOBL Public Telecommunications Division Telefonaktiebolaget LM Ericsson STEN JACOBSON Ericsson Fiber Optics AB Fig. 3 Block diagram of the digital optical fibre cable-TV transmission system ZAV 280/4 heightof six building modules (244 mm) at both the send and receive sides, fig. 2. System ZAV 280/4 has been developed in collaboration with the Swedish Telecommunications Administration. Equipment ZAV 280/4 is made up of a number of function blocks as in fig. 3. The equipment is accommodated in 19" magazines for rack mounting. The encoder (ZFV 495012/101 or 102) contains video encoders, audio encoders, data transmitter and multiplexer. The output is a 139.264 Mbit/s data stream (CMI or binary coded) which contains two video signals, eight audio signals, a 640 kbit/s data signal and synchronizing information. The encoder can also be furnished with a 280 Mbit/s optical transmitter which multiplexes data from two encoder blocks and transmits it over an optical fibre. It is then called a transmitter (ZFV 495011). The branching unit (ZFV 49505 or ZFV 49506) is a function block containing optical receivers, optical transmitters and adapter functions in various combinations. A branching unit enables the signal to be branched into at mosl six optical and one electrical output. The decoder (ZFV 495021/102 or 103) contains frame synchronization and demultiplexing for 139.264 Mbit/s in addition to a video decoder, audio decoder and data receiver. The decoder may also be furnished with a 280 Mbit/s optical receiver which demultiplexes the received signal and supplies two decoders with a 140 Mbit/s data stream each. It is then called a receiver (ZFV 495021/101). Picture encoder Picture decoder Sound encoder Data transmitter 140 Mbit/s encoder Frame multiplexer D1 D2 Optical transmitter
Page 1 and 2: ERICSSON REVIEW 4 1985 Field Trial
Page 3 and 4: Trial of Optical Fibre Cable-TV Sys
Page 5 and 6: Head end (HC] 280 Mbit/s Farsta aut
Page 7 and 8: 158 Switching equipment Fig. 7 Futu
Page 9: 160 Fig. 10 The teleconference room
Page 13 and 14: Fig. 5, above left Two-channel A/D
Page 15 and 16: Digital input signals Digital outpu
Page 17 and 18: Power ZAV 280/4 has individual powe
Page 19 and 20: Wavelength Division Multiplexing fo
Page 21 and 22: 172 Subscriber side BP-890 Controll
Page 23 and 24: Fig. 8 Transmission characteristics
Page 25 and 26: Most computer cabinets are 19" wide
Page 27 and 28: 178 Fig. 5 Modems in Series 7 Modem
Page 29 and 30: Computer Aided Production of Plasti
Page 31 and 32: Fig. 4 Product geometry displayed o
Page 33 and 34: Rectifier for Mobile Telephone Syst
Page 35 and 36: I OR | OFU OS I CMUP HlsHi W±±±h
Page 37 and 38: 188 Fig. 6 The rectifier with the o
Page 39 and 40: Fig. 9 Rectifier BMJ A01 001 with t
Page 41 and 42: The Renewal of the London Undergrou
Page 43 and 44: 194 Rickmansworth, and the Loughton
Page 45 and 46: 196 Fig. 5 Optical fibre cable rout
Page 47 and 48: 198 In planning the optical fibre n
Page 49 and 50: Fig. 9 The digital telephone DIAVOX
Page 51 and 52: 202 Fig. 11 Transmission equipment
Page 53 and 54: 204 Fig. 2 Automatic testing of mul
Page 55 and 56: 206 Relative occurrence for F Fig.
Page 57 and 58: Fig. 5 Field testing of a 140 Mbit/
Page 59 and 60: 210 Fig. 7 The system down time as
Page 61 and 62:
MTBF (years) Equipment 2-5 Transmul
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