2 specifications – Comtech EF Data SDM-100A User Manual
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SDM-100A Satellite Modem
Theory of Operation
Rev. 0
4–5
4.1.2 Specifications
Modulation Type
QPSK or BPSK
Data Rate Range
19.2 to 128 kbit/s 1/2 Rate, QPSK
28.8 to 192 kbit/s 3/4 Rate, QPSK
33.6 to 224 kbit/s 7/8 Rate, QPSK
9600 bit/s to 64 kbit/s 1/2 Rate, BPSK
Symbol Rate Range
19.2 to 128 ks/s
Test Modes
Carrier Null and Quadrature (Dual and Offset)
Frequency Range
50 to 180 MHz
Frequency Select Method
Synthesized
Frequency Step Size
2.5 kHz
Frequency Stability (RF)
±
10 PPM Internal Oscillator
Frequency Stability (SCT)
±
10 PPM Internal Oscillator
Phase Error
2.5° max.
Filtering Type
Nyquist, Pre-equalized
Spectral Occupancy
Spectral Density is -30 dB at
±
0.75 Symbol Rate
Spurious and Harmonics
-55 dBc, 0 to 500 MHz
Output Power Level Range
-5 to -30 dBm,
±
0.5 dB
Output Stability
±
0.5 dB
Output Power Adjustment
0.5 dB step size
Output Impedance
75
Ω
, 50
Ω
optional
Output Return Loss
20 dB minimum
Scrambling V.35
FEC Encoding
Convolutional K = 7 Viterbi, or Sequential Encoding
Decoding
Soft-Decision Viterbi or Sequential Rate 1/2, 3/4, or 7/8
Reported Faults
AGC Level Fault
Synthesizer
Fault
I Channel Filter Activity
Q Channel Filter Activity
Clock Activity Fault