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SDM-300A Satellite Modem
3.3.2
Configuration Demodulator
Refer to Figure 3-5.
RX-x CODE_RATE/TYPE
RX-IF FREQUENCY
DESCRAMBLER
DIFF. DECODER
Rev. 4
Receiver code rate/type selection. Select one of the following or a
variable rate selection (V) as follows:
RX-x QPSK 1/2
Code Rate
Data Rate Range
BPSK 1/2
2.4 to 1250 kbit/s
QPSK 1/2
4.8 to 2500 kbit/s
QPSK 3/4
7.2 to 3750 kbit/s
QPSK 7/8
8.4 to 4375 kbit/s
8PSK 2/3
64 to 5000 kbit/s
OQPSK 1/2
4.8 to 2500 kbit/s
OQPSK 3/4
7.2 to 3750 kbit/s
OQPSK 7/8
8.4 to 4375 kbit/s
BPSK 1/1
4.8 to 2500 kbit/s
QPSK 1/1
9.6 to 5000 kbit/s
Notes:
1. Max Symbol Rate: 2500 Kbit/s
2. Max Data Rate for Low Var Rate: 512 kbit/s
Upon entry, the current receiver rate is displayed with the flashing
cursor on the first character of the code rate on line 1. The data rate is
displayed on line 2. Press [↑] or [↓] to select one of four pre-defined
rates (A, B, C, or D). To select the currently defined variable data rate,
select RX-V, and press [ENTER] twice.
To change the rate using the variable rate selection, press [ENTER]
when RX-V is displayed. A flashing cursor is displayed on the first
character of the coding type on line 1. Press [←] or [→] to move the
flashing cursor, and [↑] or [↓] to increment or decrement the digit at the
flashing cursor. Press [ENTER] to execute the change.
Programs the demodulator receive frequency between 50 and 180 MHz,
in 1 Hz steps.
Upon entry, the current receive frequency is displayed with the flashing
cursor on the first character. Press [←] or [→] to move the flashing
cursor, and [↑] or [↓] to increment or decrement the digit at the flashing
cursor. Press [ENTER] to execute the change.
Programs the descrambler ON or OFF.
Upon entry, the status of the descrambler is displayed. Press [↑] or [↓]
to make the selection. Press [ENTER] to execute the change.
Programs the differential decoder ON or OFF.
Upon entry, the status of the differential decoder is displayed. Press [↑]
or [↓] to make the selection. Press [ENTER] to execute the change.
Operation
3–13
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