Function select: configuration: demodulator – Comtech EF Data SDM-2020 User Manual

Page 72

SDM-2020 Satellite Demodulator

Revision 4

Front Panel Operation

MN/SDM2020D.IOM

6–8

6.1.5.2

Function Select: Configuration: Demodulator

CONFIGURATION

DEMODULATOR

Press [

→} key to go to any of the following sub-menus. Press to review or

edit the menu.

Function Select: Configuration: Demodulator: RX-DR

without G.703 Data Interface (Conditional)

RX-DR QPSK

1/2

DATA RATE

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:

QPSK 1/2 3/4 7/8 5/6 2/3
8-PSK

2/3 5/6 8/9

16-QAM

3/4 7/8

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.