Comtech EF Data SFC1800A - Manual (Page 20)

Theory of Operation SFC1800A Synthesized Frequency Upconverter
3-4 TM111 - Rev. 1.0
After all of the converters have been programmed, the back up converter is then set into a “Learn
Mode.” The backup poles each converter on a continuous basis, and learns then stores the
settings of each converter. Because the switch modules are on a common protection bus, each
converter knows the address (position in the rack), and the fault status of all of the converters in
the rack. In the event of multiple failures, the highest priority converter that fails is backed up first.
The chain switch provides the primary through path between the converter RF output and the
output of the switch module without being powered. It is provided with redundant power from all
converters connected in the chain. In the event that a Upconverter needs to be replaced, the
Chain Switching Module can be removed from the back of the converter and left in place without
breaking the interconnections to adjacent converters in the chain.
Refer to Figure 3-4 for Chain Switching Operation in a 1:1 configuration, and Figure 3-5 for a 1:N
configuration.