Maintenance
SDM-300A Satellite Modem
5–6
Rev. 4
5.1.3 Demodulator
Checkout
Use the following procedure to test the demodulator.
1. Set up the equipment as shown in Figure 5-1. Refer to
Chapter 4
for the
demodulator specifications.
2. Set up the modem with an external IF loop and level. Use a properly operating
modulator, and ensure that power levels, data rates, code rates, etc., are
compatible.
3. Allow the modem to lock up. Depending on the data rate and overhead type,
lock up may take several seconds. When the green carrier detect LED is on and
the DEMUX lock fault has been cleared (where applicable), the modem will run
at the specified error rate. Run the TX power level (input amplitude) over the
full range, and offset the TX frequency from the RX frequency by 35 kHz.
Ensure the modem still runs within the specified error rate.
4. Set up the modem to check the constellation patterns with an oscilloscope that is
set in the X-Y mode. Typical constellation patterns with noise and without noise
are shown in Figure 5-4. These test points are available on the auxiliary
connector (J9, pins 6 and 8). It is not necessary to open the modem to look at
these test points.
Содержание SDM-300A
Страница 1: ...Part Number MN SDM300A IOM Revision 4 SDM 300A Satellite Modem Installation and Operation Manual...
Страница 33: ...Introduction SDM 300A Satellite Modem 1 14 Rev 4 This page is intentionally left blank...
Страница 36: ...SDM 300A Satellite Modem Installation Rev 4 2 3 Figure 2 1 Installation of the Mounting Bracket...
Страница 57: ...Operation SDM 300A Satellite Modem 3 4 Rev 4 This page is intentionally left blank...
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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...
Страница 275: ...Options SDM 300A Satellite Modem A 86 Rev 4 This page is intentionally left blank...
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...
Страница 388: ...Specifications SDM 300A Satellite Modem C 58 Rev 4 This page is intentionally left blank...
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...