CDM-600 Satellite Modem Revision 7
Front Panel Operation MN/CDM600.IOM
6–10
If ALARM ACTION is selected, the following menu will be displayed:
Select the action that will occur if the AUPC causes the maximum output power level to
be reached, either NONE or TX ALARM.
Select the action that will occur if the remote demod is unlocked. The choices are: NOM-
PWR (Nominal Power), where the output level will revert to the nominal power level set
under MANUAL or MAX-PWR, (Maximum Power), where the output level will change
to the maximum permitted. The user should then press ENTER.
CONFIG: TX: ENCODER
Select the parameter to edit using the [←] [→] arrow keys.
The Encoder options are shown in the parentheses. Select using the [↑] [↓] arrow keys,
then press ENTER. The choices are:
• Viterbi
• Sequential
• Trellis Coded Modulation - 8-PSK Rate 2/3 only (FAST option)
• TPC (Turbo) (Hardware option)
• None (uncoded)
• LDPC (Hardware option) Note: This option of encoding is only displayed if
the TPC/LDPC Codec is installed.
Select ON or OFF for Reed-Solomon using the [↑] [↓] arrow keys, then press ENTER. If
Reed-Solomon is ON, proceed to the next menu.
If None is selected, the bottom line of the display will change from the R-S selection to
the Differential Encoding selection, as shown below:
IMPORTANT
If the user selects Differential Encoding=OFF, there is no way for the
modem to resolve the phase ambiguities associated with PSK
modulations. For BPSK there is a 1 in 2 chance that the polarity of the
data will be correct. IN QPSK there is a 1 in 4 chance the data will be
correct.

ENCODER = TPC (NONE,VIT,SEQ,TCM,TPC,LDPC)

REED-SOLOMON= OFF (ON,OFF)

MAX TX PWR ACTION = NONE (NONE, TX-ALM)

REM DEMOD UNLOCK ACT = NOM-PWR(NOM, MAX)

ENCODER = NONE (NONE,VIT,SEQ,TCM,TPC,LDPC)

DIFF-ENCODER= OFF (ON, OFF)