Figure 5-1. Modulator Block Diagram - Comtech EF Data SDM-650B Installation And Operation Manual

Theory of Operation
A block diagram of the modulator is shown in Figure 5-1.
INPUT DATA
DATA SCRAMBLER
INPUT
CLOCK
CLOCK
GENERATOR
OUTPUT CLOCK
CLOCK SYNTHESIZER
MICRO-COMPUTER
PROCESSOR
BUS BUS INTERFACE
Refer to Section 5.1.2 for a detailed description of the modulator.
5–2
FORWARD ERROR
DIFFERENTIAL
CORRECTION
ENCODER
ENCODER
FILTER

Figure 5-1. Modulator Block Diagram

I CHANNEL
NYQUIST FILTERS
Q CHANNEL
NYQUIST FILTERS
MULTIPLE LOOP
SYNTHESIZER
IF
BANDPASS
FILTER
SDM-650B Satellite Modem
POWER
COMBINER
IF OUTPUT
50 to 90 MHz
or
100 to 180 MHz
OUTPUT LEVEL
CONTROL
Rev. 6