Demodulator; Figure 1-6. Power Spectral Density Chart - Comtech EF Data CDM-Qx Installation And Operation Manual

CDM-Qx/QxL Multi-Channel Satellite Modem with DoubleTalk™ Carrier-in-Carrier®
Introduction
0.00 0.10 0.20
0
-5
Comtech EF Data
CDM-Qx Transmit
-10
Power Spectral Density,
referred to symbol rate
-15
-20
-25
-30
-35
-40
-45
-50
Spectral
density,
dB
-55
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)
Input power range
(L-Band)
Acquisition range
Acquisition time
Clock tracking range
0.30 0.40 0.50 0.60
Intelsat
IESS 308/309
Limit

Figure 1-6. Power Spectral Density Chart

-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
-130 + 10log(Symbol Rate in Hz) minimum signal level
50dB AGC 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.
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.
± 100 ppm min
0.70 0.80 0.90 1.00
CDM-Qx Modulator
typically < -50 dB, and
guaranteed to be
< -45 dB at offsets
> 0.75 Rs
1–15
Revision 7
MN/CDMQx.IOM
1.10 1.20 1.30 1.40
Symbol Rate, R s
Intelsat
IESS 308/309
Limit
1.50