Comtech EF Data SLM-5650A Installation And Operation Manual page 510

I.2 Processing Flow and Symbol Rate Calculation
The SLM-5650A supports both serial and Ethernet interfaces, and provides options for framing,
modulation and spreading. Figure I-1 shows the processing flow for these functions when the
SLM-5650A 'J6 EIA530' rear panel connector and the optional Network Processor Module's Port
'1' are used for the Serial and Ethernet interfaces, respectively.
The symbol rate S
with FEC encoding, modulation, and transport overhead factors as shown in the equation
"S
=B /M C F
R R O R RS
•
Operand 1 –
•
Operand 2 – C
stated FEC code rate = "3/4")
•
Operand 3 – F
o
o
•
Operand 4 –
o
o
o
Appendix J
Figure I-1. SLM-5650A – Feature Block Diagram
(Carrier 3dB Bandwidth) is a function of the programmed data bit rate B
R
" (referred to hereafter as "Equation 1"), containing the following Operands:
F F
T C
M
= Modulation Order
O
= Code Rate of the Forward Error Correction (FEC) (e.g., CR = 0.75 if
R
= Reed Solomon Framing Factor, where:
RS
F = (n/k) where (201,219) is default RS for MIL-165A
RS
F = 1 where the RS is disabled.
RS
F
= CnC AUPC Mode or ACPC Control Framing Factor, where:
c
F = 15/16 if AUPC Mode is enabled;
C
F = 32605/32768 if ACPC Mode is enabled;
C
F = 1 if neither feature is enabled.
C
Only one of these two features (AUPC Mode or ACPC Mode)
may be enabled at any given time.
'1' if BPSK
'2' if QPSK
'3' if 8PSK
'4' if 16QAM
I–2
SLM-5650A Satellite Modem
Revision 10
R
MN-SLM-5650A