Modulator; Figure 4-2. Modulator Block Diagram - Comtech EF Data SDM-300A Installation And Operation Manual

SDM-300A Satellite Modem
4.2

Modulator

The modulator provides PSK modulated carriers within the 50 to 180 MHz range. The
types of modulation that encode the transmitted baseband data from the interface PCB
are:
•
•
•
•
Refer to Section 4.2.3 for a description of each modulation type.
A block diagram of the modulator is shown in Figure 4-2.
D ATA
IN TE R FA C E
C LK
SC T
R E FE R E N C E
Rev. 4
BPSK
QPSK
OQPSK
8PSK
O P TIO N A L
F R A M IN G U N IT
IBS /ID R , A S Y N C /AU P C
D R O P & IN S E RT
S C T
PL L
O PT IO N A L
L O

Figure 4-2. Modulator Block Diagram

O P TIO N A L
M U X
R E ED -SO LO M O N
E N C O D ER
C O N V O L U TIO N A L
E N C O D ER
D IG ITA L
B P F SIG N A L
P R O C E SS IN G
P O W E R L E VE L
B P F
C O N TR O L
Theory of Operation
M O N ITO R
&
C O N TR O L
R F
LP F
O U TP U T
R F LO O P BA C K
O U TP U T
4–5