Comtech EF Data CDD-562AL - Manual (Page 230)

CDD-562AL/564A/L Multi-Channel Demodulator Revision 0
Eb/N0 Measurement MN-CDD562AL564AL
B–2
Example: In this diagram, the (Co+No)/No measured is 4.6 dB. If Rate 1/2 QPSK is being used, this
would correspond to an E
b
/N
0
of approximately 2.6 dB.
The exact relationship used to derive the table values is as follows:
E
b
/N
0
= 10 log
10
(10
(Co+No/No )/10)
-1) - 10 log
10
(FEC Code Rate) - 10 log
10
(bits/symbol)
Where:
E
b
/N
0
and (Co+No)/No are expressed in dB
Bits/symbol = 1 for BPSK
Bits/symbol = 2 for QPSK
Bits/symbol = 3 for 8-PSK/8-QAM
Bits/symbol = 4 for 16-QAM
Code Rate for ‘uncoded’ = 1