Comtech EF Data CDM-625, Installation And Operation Manual

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CDM-625 Advanced Satellite Modem Revision 1
Front Panel Operation MN-0000036 (Ref MN/CDM625.IOM)
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.
When selecting
Reed-Solomon On
, proceed to the next menu.
CONFIG: Tx
Æ
FEC
Æ
Reed-Solomon On
Reed-Solomon Encoding =Standard(126/112)
(Standrd(126/110),IESS-310(219/201)) (
v
)
Use the
▲ ▼
arrow keys to select one of the listed parameters, then press
ENTER
. Possible
selections, depending on the Framing mode, are as follows:
•
IESS-310, open or closed network 219/201
•
IBS, open or closed network 126/112
•
EDMAC or D&I++, closed network 200/180
•
IDR, open network 225/205, 219/201 or 194/178
•
ESC++ closed network 126/112
•
Unframed closed network
ƒ Comtech standard 220/200
ƒ Legacy EF Data 225/205, with V.35 scrambling
5.4.3.5 CONFIG: Tx
Æ
Mod (Modulation)
Modulation=QPSK (B,Q,OQ,8PSK,16Q,8QAM)
FEC Rate=1/2 (1/2,3/4,7/8) (
34v
)
This menu permits the user to edit the Modulation type and the FEC rate. Select one of the
parameters using the
◄ ► arrow keys, then edit it using the
▲ ▼
arrow keys.
The Encoder type dictates the Modulation Type and FEC rate choices:
Encoder Type Modulation Type FEC Rate Choice
No Encoder
BPSK
QPSK, OQPSK
Fixed at 1/1
Fixed at 1/1
Non-Turbo Encoder
BPSK
TCM 8-PSK (FAST option)
QPSK, OQPSK
16-QAM (Vit+RS only) Fixed at Rate 1/2
Fixed at Rate 2/3
1/2, 3/4, 7/8
3/4, 7/8
5–13