Comtech EF Data DMD1050 - Manual (Page 31)

DMD1050 Satellite Modem Board Theory of Operation
MN-DMD1050 3–5
Revision 9
Sync
Data
I/O
Collector
Terrestrial
Phy
Rx DSP
Tx DSP
Digital
Baseband
Processor
M&C
DEMOD
FPGA
Universal
Modem
MOD
FPGA
Terminal
Remote
Port
Power
Regulator
2 x 10
1 x 10
-6
8
Reference
Ref. (Opt.)
Remote Serial Interfaces
DMD1050
Universal Satellite
Modem
Tx
RF
Equipment
Rx
RF
Equipment
IF Input
950-2050 MHz
IF Output
950-2050 MHz
0 to -25 dBm
+24 VDC
Asynchronous
Overhead
LAN
10 Base-T
Ethernet
Ethernet
Data
Interface
Antenna
Open
Faults
Figure 3-4. DMD1050 Universal Satellite Modem Functional Block Diagram
3.2.3 Rx Baseband Processing
The Receive Processor performs the inverse function of the Tx Processor. Data received from the
satellite passes through the BB Loopback Circuit to the Reed-Solomon Decoder to the Deframer.
The Deframer acquires the IBS/IDR/DVB frame, synchronizes the Reed-Solomon Decoder and
extracts the received data and overhead from the frame structure, placing the data into the PD
Buffer, sending the overhead data to the UIM. The data is extracted from the buffer and is sent to
the UIM. Backward Alarm indications are sent to the M&C Subsystem.
3.3 Monitor & Control (M&C)
The modems M&C system is connected to most of the circuitry on any board contained in the
modem. These connections provide status on the working condition of the circuitry as well as
providing the data required for the various measurements the modem provides. The M&C