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CDM-600 Satellite Modem Revision 7
Front Panel Operation MN/CDM600.IOM
6–36
6.3.4 MONITOR
Select the parameter to Monitor using the [←][→]
arrow keys, then press ENTER.
MONITOR: LIVE-ALARMS
An example of an Alarm screen is shown. The highest priority alarm currently active for
each of the four alarm types is shown:
Unit PSU: Power supplies (+5V, +12V, -5V, +18V, -12V) are always monitored by an
onboard supervisory IC.
TX and RX SYNTH: The PLLs in the IF sections are monitored for an unlocked
condition.
POWER CAL: Calibration data stored in EEPROM is checked at power up to verify
that the factory calibration has not been corrupted.
FPGA downloads (Main chain, Turbo FEC, Modem “Top” card, Mux and Demux) are
verified to have been loaded successfully.
Hi-Stab Freq Ref Module: No PLL Lock – This will suppress the TX carrier.
Transmit NO CLOCK: Clock activity from the Tx terrestrial source is checked, if expected. If
absent, the modem falls back to the internal SCT clock to drive the modulator.
FIFO SLIP: alarm occurs when the terrestrial clock source differs from the
programmed data rate, or may indicate a hardware failure.
TX AIS: Alarm Indication Signal (all 1’s) present at the Tx terrestrial input is
monitored.
AUPC LEVEL: If AUPC is enabled, a Tx alarm occurs if the power increase limit has
been reached.
Hi-Stab Freq Ref Module: Ref Activity Fault
Receive DEMOD LOCK: indicates either the demodulator or the following FEC decoder
cannot lock to the incoming signal.
AGC ALARM: is indicated if the demod signal level is >-20 or <-60 dBm.
FRAME SYNC: indicates that the de-framing unit (EDMAC, IBS or IDR) or Reed-
Solomon outer decoder cannot synchronize to the data being sent to it by the demod
and/or FEC decoder.
BUFF SLIP: occurs when Doppler or Plesiochronous effects cause the Rx data
buffer to empty or fill completely. The results in a reset to 50%.
RX AIS: Alarm Indication Signal (all 1’s) present at the Rx satellite input is monitored.
EbNo ALARM: occurs when the monitored level drops below that programmed by
the user in the CONFIG, RX, EbNo menu.
BUFF CLOCK: indicates that the desired buffer reference is not present, causing the
buffer to fall back on Rx satellite timing to clock its output.
MONITOR: LIVE-ALARMS STORED-EVENTS
STATISTICS RX-PARAMS AUPC-PARAMS
LIVE UNIT= NONE NET= NONE
ALARMS RECV=DEMOD LOCK XMT= NONE