Comtech EF Data CDM-625 - Page 287

CDM-625 Advanced Satellite Modem Revision 13
Forward Error Correction Options MN-CDM625
7–9
Table 7-6. Comparison of all Comtech EF Data TPC/LDPC Modes (CDM-625 with
TPC/LDPC Codec)
Mode
Eb/No at
BER = 10
-6
(typical)
Eb/No at
BER = 10
-8
(typical)
Spectral
Efficiency
(bps per Hz)
Symbol Rate
Occupied *
Bandwidth for
1 Mbps Carrier
QPSK Rate 1/2 Viterbi ** 5.5 dB 6.8 dB 1.00 bps/Hz 1.0 x bit rate 1190 kHz
BPSK Rate 1/2 LDPC
1.7 dB
1.9 dB
0.50 bps/Hz
2.0 x bit rate
2380 kHz
BPSK Rate 21/44 TPC 2.8 dB 3.0 dB 0.48 bps/Hz 2.1 x bit rate 2493 kHz
BPSK Rate 5/16 TPC 2.4 dB 3.0 dB 0.31 bps/Hz 3.2 x bit rate 3808 kHz
QPSK/OQPSK Rate 1/2 LDPC
1.7 dB
1.9 dB
1.00 bps/Hz
1.0 x bit rate
1190 kHz
QPSK/OQPSK Rate 21/44 TPC 2.8 dB 3.3 dB 0.96 bps/Hz 1.05 x bit rate 1246 kHz
QPSK/OQPSK Rate 2/3 LDPC 2.1 dB 2.4 dB 1.33 bps/Hz 0.75 x bit rate 892 kHz
QPSK/OQPSK Rate 3/4 LDPC 2.7 dB 2.9 dB 1.50 bps/Hz 0.67 x bit rate 793 kHz
QPSK/OQPSK Rate 3/4 TPC
3.4 dB
4.0 dB
1.50 bps/Hz
0.67 x bit rate
793 kHz
QPSK/OQSK Rate 7/8 TPC 4.2 dB 4.3 dB 1.75 bps/Hz 0.57 x bit rate 678 kHz
QPSK/OQPSK Rate 0.95 TPC 6.0 dB 6.5 dB 1.90 bps/Hz 0.53 x bit rate 626 kHz
8-PSK Rate 2/3 TCM **
and RS (IESS-310)
5.6 dB 6.2 dB 1.82 bps/Hz 0.56 x bit rate 666 kHz
8-QAM Rate 2/3 LDPC
4.3 dB
4.6 dB
2.00 bps/Hz
0.50 x bit rate
595 kHz
8-QAM Rate 3/4 LDPC 5.3 dB 5.5 dB 2.25 bps/Hz 0.44 x bit rate 529 kHz
8-PSK/8-QAM Rate 3/4 TPC 6.1 dB 6.7 dB 2.25 bps/Hz 0.44 x bit rate 529 kHz
8-PSK/8-QAM Rate 7/8 TPC 6.7 dB 6.9 dB 2.62 bps/Hz 0.38 x bit rate 453 kHz
8-PSK/8-QAM Rate 0.95 TPC
9.2 dB
10.2 dB
2.85 bps/Hz
0.35 x bit rate
377 kHz
16-QAM Rate 3/4 LDPC 6.7 dB 6.8 dB 3.00 bps/Hz 0.33 x bit rate 396 kHz
16-QAM Rate 3/4 TPC 7.4 dB 8.1 dB 3.00 bps/Hz 0.33 x bit rate 396 kHz
16-QAM Rate 7/8 TPC
7.9 dB
8.1 dB
3.50 bps/Hz
0.28 x bit rate
340 kHz
16-QAM Rate 3/4 **
Viterbi/Reed-Solomon
7.5 dB 8.0 dB 2.73 bps/Hz 0.37 x bit rate 435 kHz
16-QAM Rate 7/8 **
Viterbi/Reed-Solomon
9.0 dB 9.5 dB 3.18 bps/Hz 0.31 x bit rate 374 kHz
* The occupied bandwidth is defined at the width of the transmitted spectrum taken at the –10 dB points on t he plot of power
spectral density. This equates to 1.19 x symbol rate for the CDM-625 transmit filtering.
** Included for comparative purposes