Specifications

SDM-100A Satellite Modem Introduction
Rev. 0 1–5
1.4 Modem Specifications
Table 1-1 lists the operating specifications of the modem.
Table 1-1. SDM-100A Specifications
Modem Specifications
Operating Frequency Range 50 to 180 MHz, synthesized in 2.5 kHz steps.
Type of Modulation Quadrature Phase Shift Keying (QPSK), or
Bi-Phase Shift Keying (BPSK).
Operating Channel Spacing Less than 0.5 dB degradation operating with 2
adjacent-like channels, each 10 dB higher at 1.3
times the symbol rate, or a minimum of 1.2 times the
specified acquisition range.
Bit Error Rate See Table 1-2.
Phase Noise In accordance with IESS-308.
Digital Interface RS-422/449 on 37-pin D.
(Field Changeable Plug-in modules) MIL-STD-188 on 37-pin D.
(One interface per module.) V.35 on 25-pin DIN.
RS-232-C on 25-pin D.
Asynchronous.
ADPCM.
Digital Data Rate
BPSK, 1/2 Rate 9.6 to 64 kbit/s.
QPSK, 1/2 Rate 19.2 to 128 kbit/s.
QPSK, 3/4 Rate 28.8 to 192 kbit/s.
QPSK, 7/8 Rate 33.6 to 224 kbit/s.
Doppler Buffer Programmable from 64 to 65536 bits, or from 1 to
50 ms total depth.
Buffer Output Clock Transmit, Receive, Internal, or External.
Transmit and external clocks must be to data rate.
Forward Error Correction Convolutional Encoding with Soft Decision.
K=7 Viterbi Decoding, or Sequential.
Data Scrambling Selectable (International Telephone and Telegraph
Consultative Committee) CCITT V.35, or None.
Prime Power 90 to 264 VAC Auto Select, 47 to 63 Hz,
50W Max., Fused at 2A. (48 VDC optional.)
Size 1.75” H x 19.0” W x 20.0” D. Refer to Figure 1-3.
Operating Temperature
0
°
to 50
°
C.
Storage Temperature
-20
°
to +70
°
C.
Humidity 0 to 95% noncondensing.
Diagnostic Features IF Loopback.
RF Loopback.
Baseband Loopback (Bi-directional, electrical).
Fault Monitoring.
Bit Error Rate Monitoring.
Remote Control via Serial Port.