User Manual

Axell Wireless Limited
Technical Literature
15 Channel UHF Hybrid Select Repeater
Document Number 50-157401HBK Issue No. 1 Date 26/03/2008 Page 19 of 50
4.2. Channel Module Shelf 50-157403 (6 channels)
There are two, 6 channel, Channel Module Shelves in this system, one houses the Channel
Selectivity Modules that define the passbands for channels 1 to 6 and the other houses the Channel
Selectivity Modules that define the passbands for channels 7 to 12.
Each 6 channel shelf is housed in a 4U rack mount sub-rack assembly.
Downlink signals enter the Channel Module Shelves from the Downlink Splitter/Combiner shelf via the
SMA ports at the rear of the Channel Module Shelves. For the shelf that houses Channel Selectivity
Modules for channels 1 to 6 the input port is labelled “A”. On the shelf that houses Channel Selectivity
Modules for channels 7 to 13 the input port is labelled “B”
The following describes shelf 1, shelf 2 (except for the channel frequencies) is identical.
The downlink signal is split into two equal paths by 2 Way Splitter/Combiner 05-002603, each path is
then split into three equal paths by a pair of 3 Way Splitter/Combiners (05-003803), this provides six
signal paths. Each path is then fed to a Channel Selectivity Module (17-003047)
The channel modules are used to provide the required selectivity to define the operating passband;
they provide selectivity, automatic gain levelling and on frequency operation using phase-locked
tuning from a set of 16 DIP switches which digitally control the channel frequency. The DIP switches
are housed in an accompanying Channel Control Module 17-002101, one Control Module is provided
for each Selectivity Module.
After leaving the Channel Selectivity Modules each set of three paths is combined by a second set of
3 Way Splitter/Combiners (05-003803), the resultant two signal paths are further combined by another
2 Way Splitter/Combiner (05-002603) and the downlink signal then exits the Channel Module Shelf to
return to the Downlink Splitter/Combiner shelf via the SMA ports at the rear of the Channel Module
Shelves. For the shelf that houses Channel Selectivity Modules for channels 1 to 6 the output port is
labelled “D”. On the shelf that houses Channel Selectivity Modules for channels 7 to 13 the output
port is labelled “E”