Comtech EF Data SDM-650B - Manual (Page 127)

SDM-650B Satellite Modem Theory of Operation
Rev. 6 5–3
5.1.1 Specifications
Modulation Type QPSK (BPSK optional)
Frequency Range 50 to 90 MHz, or 100 to 180 MHz
Frequency Select Method Synthesized
Frequency Step Size 2.5 kHz
Frequency Stability 10 PPM
Channel Spacing 0.7 times the data rate divided by the encoding rate
Phase Error 2.5° max
Filtering Type Nyquist, re-equalized
Spectral Occupancy See Figure 5-2
dB at
± 0.75 symbol rate
Spurious and Harmonics -50 dBc minimum in-band, 40 dBc minimum out-of-band
Output Power Level Range -5 to -30 dBm
Output Power Adjustment 0.5 dB step size
Output Stability ± 0.5 dB over -5 to -25 dBm
± 1 dB over -25 to -30 dBm
Output Impedance 75 Ω (50 Ω optional)
Output Return Loss 20 dB minimum
Scrambling V.35 or none
Differential Encoding 2 Phase or none
FEC Encoding Convolutional, Rate 7/8, 3/4, or 1/2
I/O Connector DIN, 96-pin.