User Manual
Table Of Contents
- AMENDMENT LIST RECORD SHEET
- INTRODUCTION
- 1.SAFETY CONSIDERATIONS
- 2.OVERVIEW/SYSTEM DESCRIPTION
- 3.SPECIFICATION
- 4.SYSTEM DRAWINGS
- 5.SUB-UNIT MODULES
- 5.1Downlink Channelised Cell Enhancer 60-060602 (5U chassis)
- 5.1.1Bandpass Filters (02-010701)
- 5.1.2UHF 3dB Splitter (05-002603)
- 5.1.33dB UHF Splitter (05-002603)
- 5.1.4¼Watt 0- -30dB Switched Attenuator \(10-00
- 5.1.5Low Noise Amplifiers (11-007302 & 11-007402)
- 5.1.5.1Description
- 5.1.5.2Technical Specification, (11-007302)
- 5.1.5.3Technical Specification (11-007402)
- 5.1.5.3Drg. No. 11-007302, LNA Assembly With Alarm Relay
- 5.1.5.4Drg. No. 11-007370, LNA RF Circuit Diagram
- 5.1.5.5Drg. No. 11-007371, LNA DC Wiring Diagram
- 5.1.5.6Drg. No. 11-003971, LNA DC Circuit Diagram
- 5.1.610Watt Power Amplifier (12-001901)
- 5.1.73 Stage Amplifier Alarm Boards (12-002201)
- 5.1.8Dual DC/DC Converter (13-001803)
- 5.1.9Channel Selective Module (17-003012)
- 5.1.1024V Relay Board (20-001602)
- 5.2Uplink Channelised Cell Enhancer 50-060603 (5U chassis)
- 5.3Power Supply Shelf 50-060604 (4U chassis)
- 5.1Downlink Channelised Cell Enhancer 60-060602 (5U chassis)
- 6.INSTALLATION
- 7.MAINTENANCE
- APPENDIX AINITIAL EQUIPMENT SET-UP CALCULATIONS
5-Way Channelised UHF Cell Enhancer
Maintenance Handbook
H/book Number:-50-060601HBKM
Issue No:-
1
Date:-04/07/2003
Page:-
37 of 54
5.1.8 Dual DC/DC Converter (13-001803)
5.1.8.1 Description
This unit is employed where it is necessary to derive two fixed voltage power supply rails
from some higher voltage. Typically it is used to derive 5, 8, 12 or 15V from a 24V input.
The circuit is based upon a pair of LM257 series variable voltage regulators (LM2576, 12
& 15V & LM2575, 5V), which are each capable of supplying an absolute maximum of
1.5A output current. Note that at full output current, the dissipation of the device must
remain within design limits, bearing in mind the voltage which is being dropped across it.
The maximum allowable dissipation will also depend on the efficiency of the heatsink on
which the device is mounted.
5.1.8.2 Technical Specification
PARAMETER SPECIFICATION
Operating Voltage: 21 – 27V DC
Output Voltages: 12.0V & 12.0V (typical)
Output Current: 1.0A (maximum per o/p)
Connections: Screw Terminal Block
operational
:
-10ΒC to +55ΒC
Temperature range:
storage:
-40ΒC to +70ΒC
PCB Size: 85 x 63mm