Comtech EF Data cdm-570a - Summary of Specifications; Versafec ACM

CDM-570A/570AL Satellite Modem with Optional Packet Processor
Revision 5
Adaptive Coding and Modulation (ACM) Option P–19 MN-CDM570A
P.10 Summary of Specifications
P.10.1 VersaFEC ACM
System Type
Adaptive Coding and Modulation, using BPSK, QPSK, 8-QAM , 16-QAM and
VersaFEC short-block LDPC coding – total of 12 ModCods
Symbol Rate Range
37-3000 ksps
Interface
10/100 Base T Ethernet, with auto-negotiated Congestion Control
Remote SNR Reporting
Automatically reported from remote modem – built in function at the physical
layer – requires no additional overhead
Max Span of Data Rate
7:1 over range of adaptation
Switch Point (decreasing SNR)
Corresponds to SNR (Eb/No) that gives BER = 5 x 10
-8
Switch Point Hysteresis
0.3 dB
Max Fading Rate
Approximately 1 dB/second (higher if Target Eb/No margin >1 dB)
Max ModCod Update Rate
One update every two seconds (no restriction on distance between ModCods)
Configurable Parameters
• Minimum and Maximum ModCod (ModCod0 through ModCod11)
• Remote Demod Unlock Action: Maintain current ModCod
Go to minimum ModCod
• Target Eb/No margin (0-4.5 dB, 0.5 dB steps)
System Latency
54 ms max. (for a system operating at 100 ksps, and assuming a WAN
buffer of 20 ms, not including satellite path)
Monitored Parameters
• Tx and Rx ModCods
• Local and Remote SNR
(-3.0 to +22.0dB, 0.1dB resolution, ±0.5 dB accuracy)
• Config and monitor menus displaying data rate, modulation and code rate update
dynamically with ModCod
List of ModCods
See Appendix B, Table B-3