User Manual

Demand Assignment
System Overview GSI 003
605-0000-450
Draft Issue 1.3dr Date 8/02/00
Page 6 of 8
DTU Spare Spare Spare Spare
PSU1 PSU2 SC
Spare Modem Modem Modem Modem Modem Modem AU Spare AU
DTU/XTU/CU
SITESPAN
2
SITESPAN
1
SLOT 5 SLOT 9
E1IN
E1IN
E1OU
T
E1OU
T
CABINET RACK
CONTROL
55B ALARM
COMBINER
BASEBAND
DOOR LED
RF CAL
-48V FAN AUX5 AUX9
SCAUX
SCLAT
JTAG
-48VB
-48VA
BATTPOS
COMBINER BASEBAND
E5
E5
Figure 12. Modem Shelf with front covers removed
9.3.2. RF Combiner Shelf
The RF Combiner Shelf forms the interface between the Antenna/Feeder Sub-system
and individual Modem Shelves. The RF Combiner Shelf performs the functions
necessary to connect up to four RF signals to the Antenna/Feeder Sub-system.
In the transmit direction, the baseband signals from Modem Shelves one and two are
converted to RF, amplified, combined and filtered before being sent to the first antenna.
The second pair of RF channels (from Modem Shelves three and four) are similarly
treated, but are fed via a duplexer (used in the receive path for extraction of the receive
signal) to the second antenna.