Description Of The Demodulator; Overview; Figure 1-2. Demodulator Block Diagram - Comtech EF Data SDM-300L3 Installation And Operation Manual

SDM-300L3 Satellite Modem
Introduction
1.7

Description of the Demodulator

A block diagram of the demodulator is shown in Figure 1-2.
1.7.1

Overview

The demodulator converts PSK modulated carriers within the 950 to 1750 MHz range to
a demodulated baseband data stream. The converted modulation types are BPSK, QPSK,
OQPSK, and 8-PSK. The demodulator then performs FEC decoding on the data stream to
produce the error corrected data output to the data interface.
LOOPBACK
L-BAND INPUT
SWITCH
L-BAND INPUT
REF
VCXO
OC XO
OPT
HIGH
STABILITY
EXT REFERENCE
LPF
AGC
LO #1
REFERENCE
REF
SEQUENTIAL
PLL
DECODER
OPTIONAL
REED-SOLOMON
CODEC
OPTIONAL
OVERHEAD DEFRAMING
IBS/IDR, ASYNC/AUPC
DROP & INSERT
Figure 1-2
. Demodulator Block Diagram
BPF
LO #2
OPTIONAL
VITERBI
TURBO
DECODER
CODEC
MUX
PLESIOCHRONOUS
1–10
Revision 1
MN/SDM300L3.IOM
BPF
A TO D
CONVERTER
DIGITAL
SIGNAL
PROCESSING
DIGITAL
CLOCK
RECOVERY-
LOOP
DOPPLER/
INTERFACE
BUFFER