User Manual

Table Of Contents
Optical Master Unit
PRODUCT DESCRIPTION AND USER’S MANUAL
© Axell Wireless Ltd A1829300 rev H 12 (86)
2 Product and System Description
2.1 Overview
The Axell Wireless OMU is a product used in combination with fibre fed repeaters. An OMU can be equipped
to be used for frequency ranges from 88MHz to 2 170MHz.
An OMU’s basic function is to translate RF signals to light to be sent over an optical fibre, and vice versa.
In the downlink direction the OMU picks up the signal from the base station via an RF coupler system,
converts it into an analogue optical signal and transfers it over a fibre optical cable to the repeater were it is
translated back to RF and sent out via an antenna. An OMU can also be connected to a repeater. In that
case the signal is tapped from the repeater’s server antenna.
In the uplink direction the OMU receives the signal from the repeater via the fibre optical cable, converts it
to an RF signal and sends it back to the base station.
BTS
Directional
Coupler
RF
OMU
Repeater
Opto Fiber
RF
FiberOptic
Converters
Server
Antenna
An OMU-Repeater system consists of one or more Optical Master Units, OMUs and one or several fibre fed
repeaters. An OMU-Repeater system can be expanded to handle up to 24 repeaters, and cover a distance of to
up to 20 km of fibre between the OMU and the most distant repeater.
Each OMU can be equipped with up to 6 fibre optic converters. If more than 6 repeaters are needed in the
network there are two ways of expanding the system: link several OMUs together or use laser systems with
three or four colors.
Up to 4 OMUs can be cascaded and operate up to 24 repeaters as one system. When OMUs are cascaded
only one is equipped with a Control Module. This OMU is called an OMU Master and the other three
OMU slaves. The OMU Master manages the OMU slaves as well as the connected repeaters.
BTS
RepeatersOMU Units
Four OMUs cascaded in one system