Table Of Contents - Comtech EF Data SDM-100A Installation And Operation Manual

SDM-100A Satellite Modem
CHAPTER 4. THEORY OF OPERATION.................................................................. 4-1
4.1 Modulator .....................................................................................................................................................4-1
4.1.1 Theory of Operation ...............................................................................................................................4-1
4.1.2 Specifications..........................................................................................................................................4-5
4.2 Demodulator .................................................................................................................................................4-6
4.2.1 Theory of Operation ...............................................................................................................................4-6
4.2.2 Specifications..........................................................................................................................................4-6
4.2.3 Viterbi Decoding Theory ........................................................................................................................4-7
4.2.4 Sequential Decoding Theory ..................................................................................................................4-9
4.3 Monitor and Control..................................................................................................................................4-11
4.3.1 Non-Volatile Memory...........................................................................................................................4-11
4.3.2 M&C Theory of Operation ...................................................................................................................4-11
4.3.3 Remote Interface Specification.............................................................................................................4-11
4.3.4 Remote Interface Configuration ...........................................................................................................4-12
4.3.5 Modem Defaults ...................................................................................................................................4-13
4.4 Digital Interfaces ........................................................................................................................................4-14
4.4.1 RS-422 Interface...................................................................................................................................4-14
4.4.1.1 Connector Pinouts .........................................................................................................................4-17
4.4.1.2 Specification..................................................................................................................................4-18
4.4.2 V.35 Interface .......................................................................................................................................4-18
4.4.2.1 Connector Pinouts .........................................................................................................................4-21
4.4.2.2 Specification..................................................................................................................................4-22
4.4.3 RS-232-C Interface...............................................................................................................................4-22
4.4.3.1 Theory of Operation ......................................................................................................................4-23
4.4.3.2 Connector Pinouts .........................................................................................................................4-25
4.4.4 Asynchronous Interface ........................................................................................................................4-26
4.4.5 Terrestrial Interface Change .................................................................................................................4-26
CHAPTER 5. MAINTENANCE................................................................................... 5-1
5.1 System Checkout ..........................................................................................................................................5-1
5.1.1 Interface Checkout..................................................................................................................................5-1
5.1.2 Modulator Checkout ...............................................................................................................................5-2
5.1.3 Demodulator Checkout ...........................................................................................................................5-2
5.1.4 Test Points ..............................................................................................................................................5-6
5.1.4.1 Demodulator/M&C/Interface Test Points .......................................................................................5-6
5.1.4.2 Modulator Test Points .....................................................................................................................5-7
5.2 Fault Isolation...............................................................................................................................................5-8
5.3 Module Identification...................................................................................................................................5-9
APPENDIX A. REMOTE CONTROL OPERATION ...................................................A-1
A.1 General ........................................................................................................................................................ A-1
A.2 Message Structure ...................................................................................................................................... A-2
A.2.1 Start Character ...................................................................................................................................... A-2
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