Mocomtech CDM-QX - Manual (Page 39)

CDM-Qx/QxL Multi-Channel Satellite Modem with DoubleTalk™ Carrier-in-Carrier® Revision 7
Introduction MN/CDMQx.IOM
1–15
Figure 1-6. Power Spectral Density Chart
1.5.2 Demodulator
Note: FEC, Data rate range, operating modes, descrambling, input impedance/return loss etc, as
per Modulator.
Input power range
(70/140MHz IF) -15 to -45 dBm, < 2.048 Msps (desired carrier)
-15 to -40 dBm, > 2.048 and < 4.096 Msps (desired carrier)
-15 to -35 dBm > 4.096 Msps (desired carrier)
+35 dBc maximum composite, up to -5 dBm
Input power range
(L-Band) -130 + 10log(Symbol Rate in Hz) minimum signal level
50dB AGC range
Acquisition range ±1 to ±32 kHz, Symbol rate > 64 ksps (70/140 MHz)
±1 to ± (Symbol rate/2) kHz , Symbol Rate <=64 ksps (70/140 MHz)
±1 to ±200 kHz, Symbol rate > 625 ksps (L-Band)
±1 to ± 32 kHz, 64 ksps < Symbol Rate <=625 ksps (L-Band)
±1 to ± (Symbol rate/2)kHz, Symbol Rate <=64ksps (L-Band)
Programmable in 1 kHz increments.
Acquisition time Highly dependent on data rate, FEC rate, and demodulator acquisition range.
Note that Reed-Solomon increases acquisition time, due to the additional time taken for the
RS decoder to declare synchronization.
Clock tracking range ± 100 ppm min
-55
-50
-45
-40
-35
-30
-25
-20
-15
-10
-5
0
0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00 1.10 1.20 1.30 1.40 1.50
CDM-Qx Modulator
typically < -50 dB, and
guaranteed to be
< -45 dB at offsets
> 0.75 Rs
Comtech EF Data
CDM-Qx Transmit
Power Spectral Density,
referred to symbol rate
Symbol Rate, R s
Spectral
density,
dB
Intelsat
IESS 308/309
Limit
Intelsat
IESS 308/309
Limit