Comtech EF Data CDM-625 - Manual (Page 113)

CDM-625 Advanced Satellite Modem Revision 15
Front Panel Operation MN-CDM625
5–13
modulator). In BPSK, the time-order of bits out of the FEC encoder is reversed to
make the modem compatible with certain other manufacturer modems.
• For the Txα (Tx Alpha Filter Rolloff Factor) selection, you may select 0.25 instead of the
default value of 0.35.
5.2.1.3.2 CONFIG: Tx  Freq (Frequency)
Tx-IF Frequency: 0050.0000 MHz
()
To edit the Tx-IF Frequency, use the ◄ ► arrow keys to select a digit to edit, and then use the
▲▼ arrow keys to change that digit. The available ranges are 50-180 MHz, and 950-2000 MHz
(L-Band) (FAST option). The resolution is 100Hz. Press ENTER when done.
When you use the ODU menus to configure a BUC LO-frequency, this menu displays a second
line of information:
Tx-IF Frequency: 1750.0000 MHz
(LO:12500 MHz Sat:14250.0000 MHz) ()
As you edit the IF frequency, the Satellite frequency updates accordingly.
Satellite frequency = LO ± IF frequency , where the sign ± is determined
by the LO mix parameter:
• High-sided mix [–] (includes a spectral inversion);
• Low-sided mix [+].
5.2.1.3.3 CONFIG: Tx  Power
Output Power: Mode= Manual (Manual,AUPC)
Level= –20.0 dBm ()
Use the ◄ ► arrow keys to select the Output Power Mode (top line) or to edit the Output Power
Level (bottom line) and then press ENTER.
On the top line – Use the ▲▼ arrow keys to select the Output Power Mode as MANUAL or
AUPC (see next section for conditional selection).
On the bottom line – To edit the Output Power Level, use the ◄ ► arrow keys to first select a
digit of the Tx Output Power Level, and then use the ▲▼ arrow keys to change that digit. For Tx
frequencies of 50-180 MHz, the permitted level range is 0 to –25dBm. For 950-2000 MHz
(L-Band), the range is 0 to –45dBm. Press ENTER when done.