Comtech EF Data SDM-2020 - Manual (Page 61)

SDM-2020 Satellite Modulator Revision 7
Front Panel Operation MN/SDM2020M.IOM
5-19
5.6.5.1 FAULTS/ALARMS:MODULATOR
MODULATOR
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Selections available include the following:
Fault/Alarm Possible Problem and Action
IF SYNTHESIZER Modulator IF synthesizer is faulted. This is considered a major alarm and
will turn OFF the modulator output. Return the modulator for repair.
DATA CLOCK SYN
This alarm is considered a
major alarm and will turn
OFF the modulator IF output TX data clock synthesizer fault. This fault is an indication that the internal
clock VCO has not locked to the incoming data clock, or the internal clock
synthesizer has not locked to the internal reference. Check to see that the
proper data rate has been set up and selected. Verify that the incoming data
rate matches what has been selected in the modulator. Verify the frequency
of the input data clock to be within the lock range of 100 PPM. If the inputs
to the modulator are all correct and the problem still exists, replace the
modulator and return it for repair.
I CHANNEL
This alarm is considered a
major alarm and will turn
OFF the modulator IF output. Activity alarm for the I channel digital filter.An alarm in this position indicates
either a fault in the scrambler, or if the scrambler is disabled, it indicates a
loss of incoming data. If the fault is active with the scrambler turned OFF,
check to see that there is input data at the DATA I/O connector. If data is
present, the problem could be in the interface section. If the fault is active
with the scrambler turned ON, the problem could be in the modulator
section. Return the modulator for repair.
Q CHANNEL Activity alarm for the Q channel digital filter. Follow the same procedure as
for the I channel.
AGC LEVEL Output power automatic gain control level fault. Indicates that the level at
the modulator output is not the level that is programmed. Replace the
modulator and return it for repair.
MODULE Modulator module fault. Typically indicates the modulator will not
program.This could indicate a problem in the interface between the
modulator and M&C due to modulator firmware being installed incorrectly, or
a pin not making contact. Verify the modulator firmware is correctly installed.
If the problem still exists, return the modulator for repair.
IF MODULE IF module fault. Typically indicates the IF module is not responding.
CONFIGURATION Modulator configuration fault. Indicates the modulator cannot execute a
programmed configuration parameter.
1 Use the [ ←] [→] arrows to make a selection.
2 Press .