User Manual

Central Terminal Level Control Unit
Operators Manual
GSI 002
605-0000-428
Issue 1.2 Date 5/11/98
Page 1 of 14 © Copyright Airspan Communications Corporation 1998
LEVEL CONTROL UNIT
1. Introduction
The Level Control Unit (LCU) is used during system commissioning and routine
maintenance. The Unit can be used to commission the Central Terminal, and set to
poll each modem shelf hourly or daily to ensure the receiver setting is at its optimum.
One Level Control Unit may be shared by up to four modem shelves in a single rack.
2. Architecture Overview
The Level Control Unit architecture as depicted in Figure 1. Components comprise;
i. A rack mounted Level Control Unit
ii. Cables and couplers to allow the Level Control Unit to be connected to the RF
sub-system.
iii. Cables to allow the Level Control Unit to be connected to each Modem Shelf
(to support communications to each Shelf Controller).
iv. Associated system firmware upgrades required to support AGC operation in
cards such as the Shelf Controller.
The following 'channel configuration' data is entered for each dependent modem
shelf;
• Coupler, cabling and LCU losses, Note: These components are labelled to show
insertion loss.
• Mode setting for each Shelf Controller i.e. Continuous mode, hourly poll, daily
poll, automatic level control suspended.
Other channel configuration data such as frequency and PN code is automatically
extracted from each shelf controller.