Specifications

Theory of Operation SDM-650B Satellite Modem
5–2 Rev. 6
A block diagram of the modulator is shown in Figure 5-1.
INPUT
DATA
DATA
SCRAMBLER
DIFFERENTIAL
ENCODER
FORWARD ERROR
ENCODER
CORRECTION
I CHANNEL
NYQUIST FILTERS
COMBINER
POWER
NYQUIST FI LTERS
Q CHANNEL
CLOCK
GENERATOR
CLOCK
OUTPUT
INPUT
CLOCK
CLOCK SYNTHESIZER
IF
MULTIPLE LOOP
SYNTHESIZER
BANDPASS
IF OUTPUT
50 to 90 MHz
or
OUTPUT LEVEL
CONTROL
100 to 180 MHz
FILTERFILTER
MICRO-COMPUTER
BUS INTERFACE
PROCESSOR
BUS
Figure 5-1. Modulator Block Diagram
Refer to Section 5.1.2 for a detailed description of the modulator.