Comtech EF Data CDM-750 - Manual (Page 284)

CDM-750 Advanced High-Speed Trunking Modem Revision 2
Appendix E MN-CDM750
E–2
Example: In the diagram that follows, the (Co+No)/No measured is 4.6 dB. If Rate 1/2 QPSK is
used, this corresponds to an Es/No of approximately 2.8 dB (DVB‐S2).
The relationship used to derive the table values (the only simple way for DVB‐S2) is as follows:
Es/No = C/N = 10log
10
(10 ((Co + No)/ 10) -1) – 10log
10
(Spectral Efficiency)
where:
• Es/No and(Co+No)/No are expressed in dB,
and
• Spectral Efficiency includes the modulation type, code rate, overhead and
framing and is shown in Table E‐1 and
• Table
E-2 .