Specifications

Introduction SDM-100A Satellite Modem
1–2 Rev. 0
1.1 Purpose and Function
The modem is ideally suited for networks implemented with digitized voice compressors.
These types of circuits require the minimum processing delay provided by the modem’s
Viterbi decoder. A system block diagram is shown in Figure 1-2.
The modem is also employed in transportable applications, where small size and low
power consumption are important.
SDM-100A
S
A
TEL LITE
MODEM
J8
A
DPCM
RS-232,
RS-422,
V.35, or
A
SYNC
D
A
T
A
CLK
SCT
ENCODER/
MODUL
A
TOR
M&C
M&C
CP1
IF OUTPUT
TR
A
NSMIT
RF
EQUIPMENT
50 to 180 MHz
-5 to -30 dBm
INTERF
A
CE
EXT.
CLOCK
CUSTOMER
D
A
T
A
I/O
J7
J8
A
L
A
RMS
FORM C
CONT
A
CTS
COMM
A
ND
BUS
POWER
SUPPLY
90 to 264 V
A
C,
47 to 63 Hz
A
NTENN
A
REMOTE
SERI
A
L
INTERF
A
CE
J6
MONITOR &
CONTROL
D
A
T
A
CLK
DECODER
DEMOD
CP2
IF INPUT
50 to 90 MHz
100 to 180 MHz
-30to-55dBm
RECEIVE RF
EQUIPMENT
DISPL
A
Y&
KEYP
A
D
FRONT
P
A
NEL
REMOTE
(OPT.)
Figure 1-2. SDM-100A Block Diagram
The modem provides total flexibility in selection of the following data rates:
19.2 to 128 kbit/s 1/2 rate
28.8 to 192 kbit/s 3/4 rate
33.6 to 224 kbit/s 7/8 rate QPSK
9.6 to 64 kbit/s 1/2 rate BPSK
These parameters, as well as selection of elastic buffer, scrambler, differential encoder,
power levels, and carrier frequencies, can be selected from the front panel, or by remote
control via a serial interface.
Since the modem is software defined, it can be programmed to be end-to-end compatible
with other manufacturer’s modems at similar rates.