Maintenance
SDM-300A Satellite Modem
5–14
Rev. 4
5.2.3.2 Demodulator
Faults
Fault/Alarm
Possible Problem and Action
CARRIER DETECT
Carrier detect fault.
Indicates the decoder is not locked. This is the most common fault
displayed in the modem. Any problem from the input data on the
modulator end of the circuit to the output of the decoder can cause this
alarm.
First, ensure the demodulator has an RF input at the proper frequency
and power level. Ensure the demodulator data rate is properly
programmed. Refer to the fault isolation procedure for Data Clock Syn
in the modulator section. Verify the frequency of the data transmitted
from the modulator is within 100 PPM.
IF SYNTHESIZER
Demodulator IF synthesizer fault.
Indicates the demodulator IF synthesizer is faulted.
This fault is a hardware failure. Contact the Comtech EFData Customer
Support Department.
I CHANNEL
Indicates a loss of activity in the I channel of the quadrature
demodulator.
Typically indicates a problem in the modulator side of the circuit. Check
for proper RF input to the demodulator. If the input to the demodulator
is correct, then the problem is in the baseband processing.
Q CHANNEL
Indicates a loss of activity in the Q channel of the quadrature
demodulator.
Follow the same procedure for the I channel fault.
BER THRESHOLD
Indicates the preset BER threshold has been exceeded.
Setting of this alarm is done in the Utility menu. This is an alarm based
on the corrected BER reading on the front panel.
MODULE
Demodulator module fault.
Typically indicates that the demodulator module is missing or will not
program. Contact the Comtech EFData Customer Support Department.
Содержание SDM-300A
Страница 1: ...Part Number MN SDM300A IOM Revision 4 SDM 300A Satellite Modem Installation and Operation Manual...
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Страница 36: ...SDM 300A Satellite Modem Installation Rev 4 2 3 Figure 2 1 Installation of the Mounting Bracket...
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Страница 169: ...Theory of Operation SDM 300A Satellite Modem 4 18 Rev 4 This page is intentionally left blank...
Страница 176: ...SDM 300A Satellite Modem Maintenance Rev 4 5 7 WITH NOISE WITHOUT NOISE Figure 5 4 Typical Eye Constellations...
Страница 189: ...Maintenance SDM 300A Satellite Modem 5 20 Rev 4 This page is intentionally left blank...
Страница 200: ...SDM 300A Satellite Modem Options Rev 4 A 11 Figure A 2 D I with Asynchronous Overhead Data Flow...
Страница 205: ...Options SDM 300A Satellite Modem A 16 Rev 4 Figure A 3 E1 Framing Formats...
Страница 206: ...SDM 300A Satellite Modem Options Rev 4 A 17 Figure A 4 T1 Framing Formats...
Страница 237: ...Options SDM 300A Satellite Modem A 48 Rev 4 Figure A 10 IDR Interface Block Diagram...
Страница 241: ...Options SDM 300A Satellite Modem A 52 Rev 4 Figure A 11 IBS Interface Block Diagram...
Страница 257: ...Options SDM 300A Satellite Modem A 68 Rev 4 CBA Figure A 19 Reed Solomon Codec Installation...
Страница 260: ...SDM 300A Satellite Modem Options Rev 4 A 71 CBA Figure A 20 Overhead Interface PCB Installation...
Страница 265: ...Options SDM 300A Satellite Modem A 76 Rev 4 Figure A 24 8 Channel Multiplexer Installation...
Страница 273: ...Options SDM 300A Satellite Modem A 84 Rev 4 Figure A 26 Flex Mux Multiplexer Installation...
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Страница 330: ...SDM 300A Satellite Modem Remote Control Operation Rev 4 B 55...
Страница 362: ...Specifications SDM 300A Satellite Modem C 32 Rev 4 Figure C 7 8PSK BER Specification Curves 1544 kbit s...
Страница 366: ...Specifications SDM 300A Satellite Modem C 36 Rev 4 1 1 Rate Specification Figure C 9 Uncoded 1 1 BPSK QPSK and OQPSK...
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Страница 392: ...Glossary SDM 300A Satellite Modem g 4 Rev 4 This page is intentionally left blank...
Страница 398: ...Index SDM 300A Satellite Modem i 6 Rev 4 This page is intentionally left blank...