Comtech EF Data SDM-650B - Manual (Page 55)

SDM-650B Satellite Modem Configuration
Rev. 5 3–13
3.2.1.3 Specification
Circuit Supported SD, ST, TT, RD, RT, DM, RR, MOD, FAULT,
DEMOD FAULT, MC.
Amplitude (RD, RT, ST, DM, RR) 4, ± 2V differential into 100 Ω .
DC Offset (RD, RT, ST, DM, RR) 0, ± 0.4V.
Impedance (RD, RT, ST, DM, RR) Less than 100 Ω , differential.
Impedance (SD, TT, MC) 100, ± 20 Ω , differential.
Polarity True when B positive wrt A.
False when A positive wrt B.
Phasing (RD, RT) False to True transition of RT nominally in
center of RD data bit.
Symmetry (ST, TT, RT) 50%, ± 5%.
Frequency Stability (ST) ± 100 PPM.
Modulator Fault Open collector output.
15V max.
20 mA max. current sink.
Fault is open circuit.
Demodulator Fault Open collector output.
15V max.
20 mA max. current sink.
Fault is open circuit.