Comtech EF Data SDM-2020 - Manual (Page 73)

SDM-2020 Satellite Demodulator Revision 4
Front Panel Operation MN/SDM2020D.IOM
6–9
Function Select: Configuration: Demodulator: RX-DR
with G.703 Data Interface (Conditional)
RX-DR QPSK 3/4
8.448 MBPS
Programs the demodulator data rate (DR), in 1 bps steps, limited by code rate and data
interface. On entry, the current data rate is displayed with the flashing cursor on the first
character. Press [
←] or [→] to move the flashing cursor. Press [↑] or [↓] to increment or
decrement the digit at the flashing cursor. Press to execute the change.
Code Rate Data Rate
QPSK 1/2
QPSK 3/4
QPSK 7/8
QPSK 5/6
QPSK 2/3
8-PSK 2/3
8-PSK 5/6
16-QAM 3/4
16-QAM 7/8 6.313 Mbps
8.448 Mbps
32.064 Mbps
34.368 Mbps
44.736 Mbps
51.840 Mbps
1. Programming is done by either data rate or symbol rate. Data rate refers to the
equivalent serial data rate at the data interface connector.
2. Symbol rate refers to the modulation rate after framing, trellis (Viterbi) coding,
and Reed-Solomon coding are applied.
3. The framing type selection affects the symbol rate (if programming from the data
rate [RX-DR] menu), or the data rate (if programming from the symbol rate
[RX-SR] menu).
a. If data rate is programmed, the symbol rate menu is updated to reflect the
code rate and framing selections.
b. If symbol rate is programmed, the data rate display is similarly updated.