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CDM-600L Satellite Modem
Front Panel Operation
CONFIG: TX: SCRAMBLER
TX SCRAMBLER = NORMAL (NORMAL,OFF)
Select either ON or OFF, using the [↑] [↓] arrow keys, then press ENTER.
The choice of scrambler is selected automatically, and will be depend on the exact
operating mode. For example, if no framing is being used, the ITU V.35 scrambler
(Intelsat variant) will be used. If IBS framing is selected, the IESS-309 scrambler will be
used, etc.
6.3.1.4
CONFIG: RX
RX-IF DECODER
DATA=00064.000kbps
The sub-branches available are:
CONFIG: RX: RX-IF
ACQUISITION SWEEP RANGE = +/- 10 kHz
RX FREQ=1200.0000MHz SPECTRUM INVERT=OFF
Edit the Acquisition Sweep Range of the demodulator. The value of the digit is changed
using the [↑] [↓] arrow keys. Press ENTER.
The value entered determines the amount of frequency uncertainty the demodulator will
sweep over in order to find and lock to an incoming carrier. When operating at low bit
rates, large values of sweep range (compared to the data rate) will cause excessively long
acquisition times. For example: selecting ± 32 kHz with a data rate of 2.4 kbps, BPSK,
will result in an average acquisition time of around 3 minutes.
Edit the Receive Frequency (Rx FREQ) of the demodulator. Select the digit to be edited
using the [←] [→] arrow keys. The value of the digit is changed using the [↑] [↓] arrow
keys. Press ENTER. Note that the range is from 950 to 1950 MHz.
SPECTRUM INVERT should normally be in the OFF position. When in the ON
position, the receive spectrum is inverted (which is the same as reversing the direction of
phase rotation in the demodulator). Note that in BPSK mode, the demodulator will
automatically synchronize to either the normal time-ordering of bits FEC codeword pairs,
or the inverted ordering used by certain other manufacturers.
ENCODER SCRAMBLER
DEMOD
DATA DESCRAM
SYMBOL=00064.000ksym
6–13
Revision 0
MN/CDM600L.IOM
EbNo
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