Comtech EF Data SDM-2020, Installation And Operation Manual

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Operation SDM-2020 Satellite Demodulator
3–26 Rev. 3
3.3.3.3 Receive Interface Faults Menu
Refer to Figure 3-9.
Fault/Alarm Possible Problem and Action
FRAME SYNC Indicates that the demodulator cannot synchronize to the data in the
selected framing mode. Ensure the correct framing mode is selected.
DATA STABLE/AIS The data monitored for RX data is coming from the satellite. When AIS is
selected for RX data fault in the interface configuration menu, the RX
data/AIS is monitoring an alarm condition of all 1’s from the satellite.
When Data Stable is selected for RX data fault in the Interface
Configuration Menu, the RX data/AIS is monitoring a fault condition of
all 1’s or all 0’s.
This is a data stable condition meaning that the data is not transitioning.
The alarm indicates trouble in receiving data from the satellite. The
indication is a monitor function only to help isolate the source of trouble
in a system.
CLOCK PLL
(see Note)
Receiver phase-locked loop fault. Indicates the receiver Phase-Locked
Loop is at the wrong frequency or will not lock. Return the Interface card
for repair.
FIFO (see Note) This fault indicates a data under-run/over-run condition on the interface
card.
INTERFACE MODULE Interface module fault. Indicates a problem in programming the interface,
or no interface present.
This could indicate a problem in the M&C, or in the interface between the
interface section and M&C. Return the demodulator for repair.
2047 LOCK 2047 lock alarm. Indicates the 2047 lock data pattern is not locked.
Note:
This alarm is only active if 2047 Lock is ON.
BUFFER CLK ACT
(see Note)
Activity detector alarm of the selected interface RX clock. The interface
will fall back to the satellite clock when this fault is active.
BUFFER UNDERFLOW
(see Note)
Buffer underflow alarm. Indicates that a buffer underflow has occurred.
BUFFER OVERFLOW
(see Note)
Buffer overflow alarm. Indicates that a buffer overflow has occurred.
BUFFER FULL
(see Note)
Buffer full alarm. Indicates that the buffer is less than 10% or greater than
90% full.
VIDEO FRAM SYNC Indicates that the Video Frame SYNC cannot be synchronized.
Note: Not all interfaces have these features. Ensure that the interface installed is
programmed for these parameters.