Comtech EF Data CDM-625A - Page 553

CDM-625A Advanced Satellite Modem MN-CDM625A
Appendix B Revision 4
B–17
• VersaFEC-2 adds new circular or quasi-circular constellations for higher-order modulations
(above QPSK) to replace the square VersaFEC constellations.
• Es/No span from -1.3 dB (ModCod 0) to 16.3 dB (ModCod 37), giving an average of approx.
0.45 dB per ModCod, and a 17.6 dB total span.
• The overhead associated with AUPC is eliminated. (A framed mode such as EDMAC is
normally required.)
• Combined AUPC and ACM operation is possible - VersaFEC-2 permits up to 10 dB of AUPC
power increase, followed by 17.6 dB of ACM range, for a total of 27.6 dB of fade protection.
Table B-10. The VersaFEC-2 ModCod Set – Long Block
ModCod Modulation
Code
Rate
Spectral
efficiency,
bps/Hz
Block
size,
bits
Typical * Es/No
(SNR), for
BER = 1 x 10
-8
(dB)
Latency at
128 kbps
(ms)
Min.
Data Rate,
CCM Mode
(kbps)
Max.
Data Rate,
CCM Mode
(Mbps)
Min Sym
Rate, ACM
Mode
(ksps)
Max Sym
Rate, ACM
Mode (Msps)
00
BPSK
0.489
0.489
4800
-1.3
79
18.0
6.1
37
12.5
01
QPSK
0.489
0.977
9600
1.5
153
18.0
12.2
37
12.5
02
QPSK
0.537
1.075
10560
2.0
170
19.3
13.4
37
12.5
03
QPSK
0.586
1.173
11520
2.6
185
21.1
14.7
37
12.5
04
QPSK
0.611
1.221
12000
2.8
193
22.0
15.3
37
12.5
05
QPSK
0.635
1.270
12480
3.2
200
22.9
15.9
37
12.5
06
QPSK
0.660
1.319
12960
3.5
208
23.7
16.5
37
12.5
07
QPSK
0.684
1.368
13440
3.7
215
24.6
17.1
37
12.5
08
QPSK
0.733
1.466
14400
4.4
231
26.4
18.3
37
12.5
09
8-ARY
0.521
1.564
15360
5.1
246
28.1
19.5
37
12.5
10
8-ARY
0.537
1.612
15840
5.4
254
29.0
20.2
37
12.5
11
8-ARY
0.562
1.686
16560
5.6
265
30.3
21.1
37
12.5
12
8-ARY
0.586
1.759
17280
5.8
276
31.7
22.0
37
12.5
13
8-ARY
0.611
1.832
18000
6.0
287
33.0
22.9
37
12.5
14
8-ARY
0.635
1.906
18720
6.2
299
34.3
23.8
37
12.5
15
8-ARY
0.660
1.979
19440
6.5
311
35.6
24.7
37
12.5
16
8-ARY
0.684
2.052
20160
6.9
322
36.9
25.0
37
12.2
17
8-ARY
0.708
2.125
20880
7.2
333
38.3
25.0
37
11.8
18
8-ARY
0.733
2.199
21600
7.5
345
39.6
25.0
37
11.4
19
16-ARY
0.586
2.345
23040
8.1
368
42.2
25.0
37
10.7
20
16-ARY
0.611
2.443
24000
8.6
383
44.0
25.0
37
10.2
21
16-ARY
0.635
2.541
24960
8.9
398
45.7
25.0
37
9.8
22
16-ARY
0.660
2.638
25920
9.2
413
47.5
25.0
37
9.5
23
16-ARY
0.684
2.736
26880
9.6
429
49.3
25.0
37
9.1
24
16-ARY
0.708
2.834
27840
10.0
444
51.0
25.0
37
8.8
25
16-ARY
0.733
2.932
28800
10.5
459
52.8
25.0
37
8.5
26
16-ARY
0.757
3.029
29760
10.9
474
54.5
25.0
37
8.3
27
16-ARY
0.782
3.127
30720
11.4
489
56.3
25.0
37
8.0
28
32-ARY
0.660
3.298
32400
12.0
517
59.4
25.0
37
7.6
29
32-ARY
0.684
3.420
33600
12.5
535
61.6
25.0
37
7.3
30
32-ARY
0.708
3.542
34800
12.9
554
63.8
25.0
37
7.1
31
32-ARY
0.733
3.664
36000
13.3
573
66.0
25.0
37
6.8
32
32-ARY
0.757
3.787
37200
13.7
592
68.2
25.0
37
6.6
33
32-ARY
0.782
3.909
38400
14.2
610
70.4
25.0
37
6.4
34
32-ARY
0.801
4.007
39360
14.7
625
72.1
25.0
37
6.2
35
32-ARY
0.831
4.153
40800
15.2
648
74.8
25.0
37
6.0
36
32-ARY
0.855
4.275
42000
16.0
667
77.0
25.0
37
5.8
37
32-ARY
0.879
4.397
43200
16.7
685
79.2
25.0
37
5.7