Comtech EF Data CDM-750 - Manual (Page 37)

CDM-750 Advanced High-Speed Trunking Modem Revision 2
Introduction MN-CDM750
1–13
1.4.6 Demodulator (Dual IF)
70 / 140 MHz
Impedance / Connector
Input Power
Maximum Composite Level
50 to 180 MHz in 100 Hz steps
75
Ω / BNC Female. Return loss 15 dB min
Desired Carrier = -58 + 10Log(Symbol Rate in Msps) dBm min and -18 dBm max – See Fig. 1-5
The lesser of +20 dBc – 10log(Symbol Rate in Msps) or -3 dBm
L-Band
Impedance / Connector
Input Power
Maximum Composite Level
950-2150 MHz in 100 Hz steps, demodulator
50Ω, Type N Female. Return loss 10 dB min
Desired Carrier = -65 + 10log (Symbol Rate in Msps) dBm min and -25 dBm max – See Fig. 1-6.
The lesser of +30 dBc – 10log(Symbol Rate in Msps) or -10 dBm
Acquisition Range ±150 KHz ≤ 5 Msps, ≤ 500 KHz > 5 Msps.
Es/No performance as per
DVB-S2 QEF PER 1E-7
Specifications (Normal
Frames)
[Applies with one like
modulated carrier spaced 1.3 x
Symbol Rate and 10 dB higher
than the desired carrier.
Conditions are 30 Msps and
Pilots ON] Mod/Cod Es/No Mod/Cod Es/No
QPSK 1/2 1.4 16-APSK 2/3 9.9
3/5 2.7 3/4 11.2
2/3 3.4 4/5 12.0
3/4 4.6 5/6 12.4
4/5 5.1 8/9 13.8
5/6 5.6 9/10 14.0
8/9 6.7 32-APSK 3/4 14.6
9/10 6.8 4/5 15.8
8-PSK 3/5 6.4 5/6 16.6
2/3 7.4 8/9 19.1
3/4 8.5 9/10 19.5
5/6 10.0
8/9 11.3
9/10 11.6
Figure 1-5. 70/140 MHz Input Level vs. Symbol Rate