Comtech EF Data CDM-625A - Manual (Page 150)

CDM-625A Advanced Satellite Modem MN-CDM625A
Front Panel Operation Revision 3
6–24
demodulator automatically synchronizes to either the normal time-ordering of
bits FEC codeword pairs, or the inverted ordering used by certain other
manufacturers.
• Rxα (Rx Alpha Filter Rolloff Factor) – Use the ▲▼ arrow keys to select the Txα. Press
ENTER. Valid settings are:
Rxα (Rx Alpha rollout Factor) (%) Default
0.12 0.35
• Select Rxα = 0.35 if the Txα of the signal being received is 0.25 or 0.35.
• Select Rxα = 0.12 if the Txα of the signal being received is 0.20, 0.15, 0.10, or
0.05.
6.2.1.4.2 CONFIG: Rx Freq (Frequency)
Rx-IF Frequency: 0050.0000 MHz
()
Edit the Rx-IF Frequency by using the ◄ ► arrow keys to select a digit, and then using the ▲▼
arrow keys to change that digit. Press ENTER. Valid settings are:
IF Frequency Range Step Size (Increment)
70/140 MHz 50-180 MHz 100 Hz
L-Band (FAST Option) 950-2250 MHz 100 Hz
When you use the ODU menus to configure an LNB lockout frequency, this screen displays a
second line of information (this example uses low-sided mix):
Rx-IF Frequency: 1200.0000 MHz
(LO:12500 MHz Sat:13700.0000 MHz) ()
The Satellite frequency updates accordingly as you edit the IF frequency.
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 [+].