C
N
N
C
N
E
S
N
0
E
t
N
0
E
Dec
N
0
E
b
N
0
P300H
P300 Modem Installation and Operating Handbook
Page 151
8.12.5 Tables to Convert (C+N)/N to Eb/No
4.6
2.75
4.8
3.05
Adjust for
Adjust for
Adjust for
modulation:
FEC Rate:
RS Codec:
BPSK: -0dB
½ Rate: +3.0dB
(n,k,t)=
QPSK: -3.0dB
¾ Rate: +1.25dB
(126,112,7): +0.51dB
OQPSK: -3.0dB
I
Rate: +0.58dB
(219,201,9): +0.37dB
8PSK: -4.77dB
E
Rate: +1.76dB
(225,205,10): +0.40dB
5.0
3.35
5.2
3.64
5.4
3.92
5.6
4.20
5.8
4.47
6.0
4.74
6.2
5.01
6.4
5.27
6.6
5.53
6.8
5.78
7.0
6.03
7.2
6.28
7.4
6.53
7.6
6.77
7.8
7.01
8.0
7.25
8.2
7.49
8.4
7.72
8.6
7.95
8.8
8.19
9.0
8.42
9.2
8.64
9.4
8.87
9.6
9.10
9.8
9.32
10.0
9.54
10.5
10.09
11.0
10.64
11.5
11.18
12.0
11.72
12.5
12.25
13.0
12.78
13.5
13.30
14.0
13.82
14.5
14.34
15.0
14.86
15.5
15.38
16.0
15.89
16.5
16.40
17.0
16.91
17.5
17.42
18.0
17.93
18.5
18.44
19.0
18.94
19.5
19.45
>20
=(C+N) / N
(error <0 .04dB)
Example: 8SPK with
E
Rate TCM FEC, & RS=(219,201,9)
(C+N)/N=
C/N=
8PSK so
2/3 Rate FEC, so
RS Code (219,201,9) so
8.4dB
7.72dB
subtract 4.77dB
add 1.76dB
add 0.37dB
Measure
Look up
Calculate Eb/No = C/N - 2.64dB