Description of the demodulator, Overview, 7 description of the demodulator – Comtech EF Data SNM-1001L User Manual
Page 33: 1 overview
SNM-1001L Satellite Modem
Revision 1
Introduction
MN/SNM1001L.IOM
1–9
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,
Offset QPSK, and 8-PSK. The demodulator then performs FEC decoding on the data
stream to produce the error corrected data output to the data interface.
Figure 1-2. Demodulator Block Diagram
DIG
I
T
A
L
SIG
N
A
L
PROC
E
S
S
I
N
G
DIG
I
T
A
L
CL
O
C
K
RECO
V
E
R
Y
-
LO
O
P
S
W
I
T
C
H
R
E
F
V
C
X
O
R
E
F
P
L
L
O
C
X
O
O
P
T
H
I
G
H
S
T
A
B
I
L
I
T
Y
A
G
C
L
PF
BPF
LO #2
L
O
O
P
B
A
C
K
L-BAND INPUT
L-BAND INPUT
B
P
F
A T
O
D
CONV
E
R
T
E
R
L
O #1
REFERENCE
VITERBI
DECODER
S
EQUENTIAL
DECODER
OPTIONAL
REED-SOLOMON
CODEC
DOPPLER
/
PLESIOCHRO
N
O
U
S
BUFFER
MUX
I
N
T
E
RFACE
E
X
T
R
E
F
E
R
E
N
C
E
OPTIONAL
TURBO
CODEC