Comtech EF Data CDM-625A, Installation And Operation Manual

Page: 636 / 756

CDM-625A Advanced Satellite Modem MN-CDM625A
Appendix F Revision 4
F–30
•
Power Available / MHz = 1995.26 / 36 = 55.424 W
•
If a carrier uses 24 dBW, its PEB = 10
2.4
/ 55.424 = 4.532 MHz
This corresponds to 12.59% of available transponder power.
CnC Ratio
Ratio of Interfering Carrier Power to Desired Carrier Power (unit in dB).
The
Interfering Carrier
is the Tx Carrier from local modulator; the
Desired Carrier
is the carrier from the
distant end received by the local demodulator.
At the station transmitting C1: CnC Ratio (in dB) = PowerC1 (in dBm) – PowerC2 (in dBm)
Eb/No
Ratio of Energy per bit (Eb) to Noise density (No) (unit in dB):
• Eb/No = C/No – 10log(DR) [ where DR is the Data Rate ]
•
Eb/No = Es/No – 10log(SE) [
where SE is Spectral Efficiency
]
Es/No
Ratio of Energy per symbol (Es) to Noise density (No) (unit in dB):
• Es/No = C/No – 10log(SR) [ where SR is the Symbol Rate ]
•
Es/No = Eb/No + 10log(SE) [
where SE is Spectral Efficiency
]
C/N
Ratio of Carrier Power (C) to Noise (N) (unit in dB):
Equivalent to Es/No when calculated in the Symbol Rate bandwidth.
C/No
Ratio of Carrier Power (C) to Noise Density (N
o
) (unit in dBHz)