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 25 of 50
4.3. Channel Module Shelf 50-157404 (3 channels)
There is one, 3 channel, Channel Module Shelf in this system, it houses the Channel Selectivity
Modules that define the passbands for channels 13 to 15 and is housed in a 4U rack mount sub-rack
assembly.
Downlink signals enter the Channel Module Shelf from the Downlink Splitter/Combiner shelf via the
SMA port labelled “C” at the rear of the Channel Module Shelf.
The downlink signal passes through 2 Way Splitter/Combiner 05-002603 (this has one of its outputs
terminated with a 50 Load Termination (93-930003) providing scope for future expansion), the path
is then split into three equal paths by a 3 Way Splitter/Combiner (05-003803), 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 the three paths are combined by a second 3 Way
Splitter/Combiner (05-003803), the resultant signal path then passes through a second 2 Way
Splitter/Combiner 05-002603 (with one of its inputs terminated with a 50 Load Termination (93-
930003) providing scope for future expansion). The downlink signal then exits the Channel Module
Shelf to return to the Downlink Splitter/Combiner shelf via the SMA port labelled “E” at the rear of the
Channel Module Shelf