Comtech EF Data SDM-650B - Manual (Page 26)

Introduction SDM-650B Satellite Modem
1–2 Rev. 5
1.1 Purpose and Function
The modem is a high performance, full-duplex, Bi-Phase Shift Keying/Quadrature Phase
Shift Keying (BPSK/QPSK), digital modulator/demodulator (modem), for Frequency
Division Multiple Access (FDMA) satellite communication systems.
The modem provides an interface between Single Channel Per Carrier (SCPC) fixed-rate
terminal equipment, having a data rate of 19.2 kbit/s to 3.584 Mbit/s.
The modem also provides an interface between IF converter equipment operating in a 50 to
90 MHz band, or 100 to 180 MHz band (Figure 1-2).
CUSTOMER
DATA
DIGITAL
INTERFACE MODULATOR
ENCODER/ TRANSMIT
RF EQUIPMENT
REMOTE
SERIAL
INTERFACE
MICRO- POWER
AC POWER
ANTENNA
SUPPLY COMPUTER
FAULT
INDICATORS
RECEIVE
RF EQUIPMENT DECODER
DEMODULATOR/
SATELLITE
DATA MODEM
SDM-650B
Figure 1-2. Satellite Communications System with an SDM-650B