Comtech EF Data SDM-9000 User Manual
Page 14
Preface
SDM-9000 Satelite Modem
vi
Rev. 4
5.5.2.2 ECL ........................................................................................................................................................... 5–20
5.5.2.3 MIL-STD-188 ........................................................................................................................................... 5–20
5.5.3 Theory of Operation ......................................................................................................................................... 5–21
5.5.3.1 Transmit Data Path .................................................................................................................................... 5–23
5.5.3.2 Receive Data Path ..................................................................................................................................... 5–24
5.5.3.3 Loopbacks ................................................................................................................................................. 5–26
5.5.3.3.1 Baseband Loopback ........................................................................................................................... 5–26
5.5.3.3.2 Interface Loopback ............................................................................................................................ 5–27
5.5.3.4 Engineering Service Channel (ESC) ......................................................................................................... 5–27
5.6 Backward Alarm Theory and Connections ......................................................................................................... 5–28
CHAPTER 6. MAINTENANCE......................................................................................... 6–1
6.1 System Checkout .................................................................................................................................................... 6–1
6.1.1 Interface ............................................................................................................................................................ 6–1
6.1.2 Modulator ......................................................................................................................................................... 6–3
6.1.3 Demodulator ..................................................................................................................................................... 6–8
6.1.4 Test Points ........................................................................................................................................................ 6–10
6.1.4.1 Interface PCB ............................................................................................................................................ 6–10
6.1.4.2 Modulator PCB ......................................................................................................................................... 6–11
6.1.4.3 Demodulator PCB ..................................................................................................................................... 6–12
6.2 Fault Isolation......................................................................................................................................................... 6–13
6.2.1 Guidelines ......................................................................................................................................................... 6–13
6.2.2 System Faults/Alarms ....................................................................................................................................... 6–14
6.2.2.1 Fault/Alarm Display and Description........................................................................................................ 6–18
6.2.2.2 Fault/Alarm Analysis ................................................................................................................................ 6–19
6.2.2.2.1 Modulator Faults ................................................................................................................................ 6–19
6.2.2.2.2 Demodulator Faults............................................................................................................................ 6–20
6.2.2.2.3 TX Interface Faults ............................................................................................................................ 6–22
6.2.2.2.4 RX Interface Faults ............................................................................................................................ 6–23
6.2.2.2.5 Common Equipment Faults................................................................................................................ 6–25
6.2.2.2.6 Backward Alarms............................................................................................................................... 6–26
6.3 Module Replacement ............................................................................................................................................. 6–27
6.4 Module Identification ............................................................................................................................................ 6–27
6.5 Repacking for Shipment ........................................................................................................................................ 6–27
APPENDIX A. OPTIONS .................................................................................................. A–1
A.1 Reed-Solomon Codec ............................................................................................................................................ A–1
A.1.1 Specifications................................................................................................................................................... A–2
A.1.2 Theory of Operation......................................................................................................................................... A–2
A.1.2.1 Reed-Solomon Encoder............................................................................................................................ A–2
A.1.2.2 Reed-Solomon Decoder............................................................................................................................ A–5
A.1.3 Installation ....................................................................................................................................................... A–7
A.1.3.1 Unpacking Instructions............................................................................................................................. A–7
A.1.3.2 Tools Required ......................................................................................................................................... A–7
A.1.3.3 Installation Procedure ............................................................................................................................... A–8
A.2 Direct Broadcast Satellite ..................................................................................................................................... A–10