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CDM-Qx Satellite Modem Revision 5
Front Panel Operation MN/CDMQx.IOM
5–16
If the user changes a parameter within this hierarchy, the other parameters may
become invalid. In this case, the software will change those other parameters, in
order that the configuration remains valid at all times.
Example: Suppose the user has selected Viterbi + Reed Solomon, QPSK, Rate
1/2. Now, the user changes the modulation type from QPSK to 16-QAM. In this
case, Rate 1/2 is no longer a valid code rate, and so it will be automatically
changed to the nearest valid code rate (Rate 3/4). Each of the configuration sub-
branches will now be described in detail.
(ConfigTxFEC) – TX FEC TYPE
All possible choices are presented at all times. If an option is not installed
(either Hardware, or FAST) or not valid, the ◄ ► arrow keys will force the
cursor to skip past the unavailable choice.
FEC Type RULES COMMENT
Vit (Viterbi) Always valid
Vit+R-S (Viterbi +Concatenated
Reed-Solomon)
Always valid
TCM+R-S (Trellis Coded
Modulation + Concatenated Reed-
Solomon)
If 8-PSK FAST is enabled Fixed at 8-PSK and
Rate 2/3
TPC (Turbo) If the TPC codec is installed
(ConfigTxMod) – MODULATION SCHEME
All possible choices are presented at all times. If an option is not installed
(either Hardware, or FAST) or valid , the ◄ ► arrow keys will force the
cursor to skip past the unavailable choice.
CASE RULES
BPSK Valid for all FEC types except TCM+R-S
QPSK Valid for all FEC types except TCM+R-S
8-PSK Valid for TCM+R-S, TPC (Turbo) requires 8-PSK FAST option
16-QAM Valid for Viterbi + R-S, TPC (Turbo) requires 16-QAM FAST option
Modulation: BPSK QPSK 8
-
P
SK
16-QAM (◄ ►, ENT)
Tx FEC: Vit Vit+RS TCM+RS
TPC (◄ ►, ENT)
IMPORTANT
IMPORTANT