Comtech EF Data SDM-650B - Manual (Page 29)

SDM-650B Satellite Modem Introduction
Rev. 5 1–5
1.3 System Specification
Table 1-1 lists the operating specifications of the modem.
Table 1-1. Operating Specifications
System Specifications
Operating Frequency Range 50 to 90 MHz, or 100 to 180 MHz. Synthesized in
2.5 kHz steps.
Type of Modulation QPSK.
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 75 kHz minimum.
BER See Table 1-2.
Digital Interface RS-422/-449.
V.35.
DS-1 STD.
G.703.
Others optional.
Digital Data Rate:
Variable Rate
Single Rate
19.2 to 3584 kbit/s configurable. Choice of up to four
pre-defined rates, or variable rate option.
19.2 to 48 kbit/s, 1/2 rate BPSK only.
19.2 to 2048 kbit/s.
19.2 to 3584 kbit/s.
2048 kbit/s maximum for 1/2 rate.
3072 kbit/s maximum for 3/4 rate.
3584 kbit/s maximum for 7/8 rate.
Forward Error Correction Convolutional encoding with soft decision, sequential,
or K=7 Viterbi decoding.
Data Scrambling Selectable.
CCITT V.35.
None.
Diagnostic Features RF Loopback.
IF Loopback.
Digital Data Loopback.
Fault Monitoring.
BER Monitoring.
Remote Control via Serial Port.
Prime Power 90 to 132 VAC, or 180 to 264 VAC, 47 to 63 Hz.
75W maximum, fused at 2A.
-48 VDC optional.
Size 5.25” x 19.0” x 18.0” (3RU).
Additional Modulator Specifications
Output Power -5 to -30 dBm, adjustable in 0.5 dB steps.
+5 to -15 dBm with high power option.
Output Spurious and Harmonics -50 dBc in-band (50 to 90 MHz, or 100 to 180 MHz).
-40 dBc out-of-band.
Output Impedance 75 Ω .
Output Return Loss 20 dB.
Output Frequency Stability ± 10 PPM.
Data Clock Source Internal or External.
Internal Data Clock Stability ± 50 PPM.