Comtech EF Data CDM-625 - Page 15

CDM-625 Advanced Satellite Modem Revision 13
Table of Contents MN-CDM625
xi
7.4 Reed-Solomon Outer Codec ................................................................................................ 7–3
7.4.1 Closed Network Modes ............................................................................................................................ 7–3
7.4.2 Open Network Modes .............................................................................................................................. 7–4
7.5 Trellis Coding (FAST Option) ................................................................................................ 7–4
7.6 Turbo Product Codec (Hardware Option) ............................................................................. 7–5
7.7 TPC and Low Density Parity Check (LDPC) coding ................................................................. 7–6
7.7.1 Introduction ............................................................................................................................................... 7–6
7.7.2 LDPC versus TPC ........................................................................................................................................ 7–7
7.7.3 End-to-End Processing Delay ................................................................................................................. 7–10
7.8 VersaFEC
(Short-block LDPC) .............................................................................................. 7–11
7.8.1 VersaFEC Extensions ............................................................................................................................... 7–13
7.8.1.1 Extended CCM Codes......................................................................................................................... 7–13
7.8.1.2 Ultra-Low-Latency (ULL) Codes ......................................................................................................... 7–13
7.9 Uncoded Operation (No FEC) ............................................................................................. 7–14
CHAPTER 8. AUTOMATIC UPLINK POWER CONTROL (AUPC) .................................... 8–1
8.1 Introduction ....................................................................................................................... 8–1
8.2 Setting AUPC Parameters .................................................................................................... 8–2
8.2.1 Target Eb/No ............................................................................................................................................. 8–2
8.2.2 Max Range ................................................................................................................................................. 8–2
8.2.3 Alarm .......................................................................................................................................................... 8–3
8.2.4 Demod Unlock ........................................................................................................................................... 8–3
8.3 Compensation Rate ............................................................................................................. 8–3
8.4 Monitoring ......................................................................................................................... 8–4
CHAPTER 9. CLOCK MODES AND DROP AND INSERT (D&I) ........................................ 9–1
9.1 Introduction ....................................................................................................................... 9–1
9.2 Transmit Clocking ............................................................................................................... 9–1
9.2.1 Internal Clock ............................................................................................................................................. 9–1
9.2.2 TX Terrestrial.............................................................................................................................................. 9–2
9.2.3 RX Loop-Timed, RX=TX ............................................................................................................................. 9–2
9.2.4 RX Loop-Timed, RX<>TX (Asymmetric Loop Timing) ............................................................................ 9–2
9.2.5 External TT with ST = RX Satellite ............................................................................................................ 9–2
9.3 Receive Clocking ................................................................................................................. 9–4
9.3.1 Buffer Disabled (RX Satellite) ................................................................................................................... 9–4
9.3.2 Buffer Enabled, TX=RX (TX Terrestrial or Int (SCT) Clock) ..................................................................... 9–4