Comtech EF Data SDM-300L3 - Manual (Page 81)

SDM-300L3 Satellite Modem Revision 1
Front Panel Operation MN/SDM300L3.IOM
4–13
FUNCTION SELECT: CONFIGURATION: MODULATOR:
CARRIER MODE
CARRIER MODE
NORMAL-MODULATED
Programs the modem for alternate carrier modes. All modes, except Normal-Modulated
are Test Modes. Four modes of operation are available:
NORMAL-MODULATED This mode is normally selected.
CENTER-CW Generates a CW-carrier at the current modulator frequency. This can be used to
measure the output frequency.
DUAL-CW Generates a dual side-band suppressed carrier signal. Side-bands are at one-half of
the symbol rate from the carrier. This is used to check the channel balance and
carrier null.
OFFSET-CW Generates a single, upper, side-band-suppressed carrier signal. The upper side-
band is at one-quarter of the symbol rate from the carrier. When inverted spectrum
is selected, this generates a single, lower, side-band-suppressed carrier.
Upon entry, the Center mode is displayed. To activate this test mode, press .
Press [
↑ ] or [ ↓ ] to select the desired mode. To return to the Configuration menu, press
[CLEAR].
FUNCTION SELECT: CONFIGURATION: MODULATOR:
MODEM REFERENCE
MODEM REFERENCE
INTERNAL
Select either: Internal, EXT1 MHz, EXT5 MHz, EXT 10MHz, EXT 20MHz, or
Output 10 MHz.
IMPORTANT
Use only Internal or EXT 10 MHz with a Block Up Converter (BUC) or
Outdoor Unit (ODU).
Upon entry, the current status of the scrambler is displayed. Press [
↑ ] or [ ↓ ] to make the
selection. Press to execute the change.
Note: If any EXT REF is selected for the modem reference and is disconnected or not
present at CP3, an alarm is generated, and the modem switches to its Internal Clock.