Harris Atlas DVL400, Technical Manual

Page: 116 / 180

4-16 888-2473-001 2/25/03
WARNING: Disconnect primary power prior to servicing.
Section 4 Theory of Operation ATLAS Series™
4.4.3 Backplane Interface Board
The Backplane Interface Board is accessed from the rear of the transmitter and is
located just above the PA Module compartment. This board has no active
components. Its function is to distribute RF, low voltage and control signals to the
PA modules. There is another Backplane Interface Board located in the second PA
cabinet of the DVL 4300 and DVL 5300 with identical functionality. There are 2
versions of the Backplane Interface Board:
•
8-Way Backplane Interface - Used in transmitter models with 6 or 8
modules and all 2 cabinet versions. Figures 4-6 and 4-8 show the RF
splitter configuration as part of the complete 8 and 6 PA module systems.
Note the resistive loads on the un-used ports.
•
4-Way Backplane Interface - Used in all transmitter models with 4
modules or less. Figures 4-7, 4-9 and 4-10 show the RF splitter
configuration as part of the complete 4, 3 and 2 PA module systems.
Note the resistive loads on the un-used ports.
NOTE:
The only difference between the 2 boards is the RF splitter and the number of
module connectors.
4.4.3.1 RF Splitter
The output of the DCU drives the 8-way (or 4-way) hybrid splitter on the Backplane
Interface Board. This type of splitter provides good isolation for the exciter and is
broadband, covering the entire UHF range.
4.4.3.2 Control Distribution
The System Control Bus is also distributed to all of the PA Modules from here. The
control bus includes both dedicated parallel control lines and the CAN (Controller
Area Network) bus.
NOTE:
There is a loop through connection for the System Control Bus for the second
PA Cabinet used with the DVL 4300 and DVL 5700. The system Control bus
cable connects from J17 to J17 on the 2 Backplane Interface Boards. This is
the only control connection for the second PA cabinet.