Comtech EF Data DT-4500-A Series - Manual (Page 143)

DT-4500-A Series Downconverters Revision 0
Appendix B MN-DT4500A
B–3
B.3 Redundant Configurations
Comtech EF Data DT-4500-A Series Downconverters can be configured in several different
redundant subsystem "Daisy Chain" configurations to meet the reliability requirements of a
communication system. These configurations include:
• 1:1 Redundant Systems
o Single Source IF Output Configuration: The online downconverter uses an IF transfer
switch to switch the IF signal. A single switched IF output is provided to and from the
online downconverter. The transfer switches are contained in the RSM installed in the
online downconverter. When a fault occurs in the online downconverter, the RSM is de-
activated to switch out the online downconverter, and switch the IF output to the
backup downconverter. Figure B-1 depicts the cable connections between the
downconverters. Figure B-2 shows the block diagram of this 1:1 redundant
downconverter configuration.
o Dual Source IF Output Configuration: Two IF outputs, IF Output #1 (priority) and IF
Output #2, are switched in the RSM to provide redundant operation of the
downconverters. The downconverters provide two switched IF outputs, IF Output #1
(priority) and IF Output #2. If Downconverter #1 faults, Downconverter #2 backs up the
priority channel and IF Signal #2 is not operational. Figure B-5 depicts the cable
connections between the downconverters. Figure B-6 shows the block diagram of the
1:1 redundant, dual source RF input, downconverter configuration.
• 1:N Redundant Systems
o An IF switch in the RSM is used to switch the IF output of a faulted online
downconverter to the backup downconverter. Figure B-7 depicts the cable connections
between the downconverters. Figure B-8 shows the block diagram for this 1:N
redundant "Daisy Chain" downconverter configuration.