Range Of Data Rates; Rx/Tx Error Performance Characteristics; Table B-1. The Versafec Modcod Set - Comtec CDM-840 Installation And Operation Manual

CDM-840 Remote Router
Appendix B
Table B-1 specifies the 12 modulations types / code rates that comprise the VersaFEC ModCod
Set. These chosen modulation types (BPSK, QPSK, 8-QAM and 16-QAM) and code rates afford a
continuous progression of performance in terms of both Eb/No and spectral efficiency – essential
aspects of a well-engineered ACM system.
Modulation Code Rate
BPSK 0.488
QPSK 0.533
QPSK 0.631
QPSK 0.706
QPSK 0.803
8-QAM 0.642
8-QAM 0.711
8-QAM 0.780
16-QAM 0.731
16-QAM 0.780
16-QAM 0.829
16-QAM 0.853
B.3.1

Range of Data Rates

See Sect. 1.4 CDM-840 SPECIFICATIONS for the range of available data rates.
B.4 CDM-840 Rx/Tx Error Performance Characteristics
For Rx DVB-S2 Operation: Figure B-2 through Figure B-5 show the guaranteed error
performance characteristics of the CDM-840 while receiving with Normal frames (64,800 bits),
Pilots ON.
For Tx VersaFEC Operation: Figure B-6 through Figure B-9 illustrate the guaranteed error
performance characteristics of the CDM-840.

Table B-1. The VersaFEC ModCod Set

Spectral
Block size, Typical Eb/No, for
Efficiency,
bits BER = 5 x 10
bps/Hz
0.49 2k
1.07 4.1k
1.26 4.1k
1.41 4.1k
1.61 4.1k
1.93 6.1k
2.13 6.1k
2.34 6.1k
2.93 8.2k
3.12 8.2k
3.32 8.2k
3.41 8.2k
B–4
Latency at
64 kbps, in
-8
milliseconds
2.4 dB 26
2.2 dB 53
2.7 dB 59
3.4 dB 62
3.8 dB 66
4.6 dB 89
5.2 dB 93
5.6 dB 97
6.3 dB 125
7.0 dB 129
7.5 dB 131
8.0 dB 132
MN-CDM840
Revision 3
Min. Data Rate, Max. Data Rate,
CCM mode CCM mode
16.00 kbps 2.19 Mbps
17.07 kbps 4.80 Mbps
20.19 kbps 5.67 Mbps
22.577 kbps 6.34 Mbps
25.69 kbps 7.22 Mbps
30.83 kbps 8.67 Mbps
34.14 kbps 9.60 Mbps
37.44 kbps 10.53 Mbps
46.80 kbps 13.26 Mbps
49.92 kbps 14.04 Mbps
53.04 kbps 14.91 Mbps
54.60 kbps 15.35 Mbps