Comtech EF Data CDM-570AL - Page 601

CDM-570A/570AL Satellite Modem with Optional Packet Processor
Revision 5
DoubleTalk Carrier-in-Carrier Option G–35 MN-CDM570A
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)
Co+No/No
Ratio of Carrier Density (C
o
) + Noise (N
o
) to Noise Density (N
o
) (unit in dB):
C/N = C/N
o
– 10log(B) [where B is bandwidth in Hz]
E
b
/N
o
= C/N
o
– 10log(DR) [where DR is data rate in bits/sec]
= C/N + 10log(B) – 10log(DR)
= C/N – 10log(SE) [where SE is Spectral Efficiency]
E
b
/N
o
= 10log (10
((Co+No/No)/10)
– 1) – 10log(SE) [where SE is Spectral Efficiency]
[Note: Spectral Efficiency is in bps / Hz]