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

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189 The remainder of the components and materials have been chosen in accordance with the requirements set by Underwriters Laboratories in the US. Mechanical construction System A 19" rack has been designed for system BZA201 08. The rack is 1800 mm high, 585 mm wide and 365 mm deep. The rack has a built-in rail system for the connection of a battery fuse unit, distribution unit and rectifier. If the plant comprises several racks they are interconnected by means of horizontal copper bars. Rectifier The rectifier is constructed for installation in a 19" rack and designed for natural cooling (self-convection), fig. 6. The rear plate of the unit is a large heat sink. When the rectifier is mounted in the rack the cooling flanges are automatically inserted in the cooling channel of the rack. In order to obtain sufficient creepage distance between the power semiconductors and the heat sink, the semiconductors are mounted on aluminium brackets that are pressed against the heat sink but insulated from it by a sheet of capton foil, fig. 7. This means that the heat sink does not have to be protected against human contact. The semiconductors are connected to two printed board assemblies, which are mounted in parallel with the heat sink. The transistors are mounted on the foil side of the upper board with their drive circuits close by on the same board. The two control units are plugged into this printed board, as are the capacitors and the primary side of the transformer. The primary and secondary bridges and the output filter are connected to the lower board. The rectifier is connected to the mains by means of plugs and to the current bus-bars of the system via the output switch. This means that there is not need to call in an authorized electrical contractor if a rectifier has to be changed. The rectifier cover is made of perforated steel and screens radiated interference. Fig. 7 An angle bracket with power transistors fixed to the large heat sink (see also fig. 6). An insulating foil with good heat transfer properties is placed between the bracket and the heat sink
Fig. 9 Rectifier BMJ A01 001 with the front panel open, showing the inner front panel, which provides screening. A simplified circuit diagram is printed on this panel, and the measuring instrument and LEDs are mounted in the top left-hand corner. The operating handle for the output switch is placed in the bottom left-hand corner. Fig. 8 Rectifier BMJ 401 001 with the outer front panel closed. The cut-out in the panel gives access to the electronic measuring instrument for voltage and current, the light emitting diodes that indicate operating states and the control switch (for selecting the operating mades ON, OFF/RESET or CHARGE). The output switch is placed on the left side of the unit. It connects the rectifier output circuit to bars in the rack The components on the mains side are installed in screened compartments in order to minimize the conducted interference to the mains. Heavy components, such as chokes, transformers and the large electrolyte capacitors, are mounted in the perforations in the unit frame. The plug-in printed board assemblies are held by guide rails in the case. The unit has an inner and an outerfront panel. All control devices and instruments are mounted on the inner panel. Only items needed for normal operation are accessible through the outer panel, fig. 8. HMIMMI Installation The system construction ensures easy installation and rapid putting into operation. Each rack in BZA20108 is delivered on site as a fully tested unit equipped with a distribution unit, battery fuse unit and rectifier. When the equipment in installed it is only necessary to check that there is no transport damage. The installation work consists merely of setting up the racks and connecting mams cables and distribution cables. The rectifier is designed for high personal safety. All live parts are inaccessible even when the outer front panel is
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 and 10: 160 Fig. 10 The teleconference room
Page 11 and 12: GERHARD GOBL Public Telecommunicati
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: 188 Fig. 6 The rectifier with the o
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

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

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