Adjacent channel interface performance, Frequency stability, Digital data rates – Comtech EF Data SDR-54A User Manual
Page 64: 5 adjacent channel interface performance, 6 frequency stability, 2 digital data rates
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SDR-54A Satellite Demodulator
Revision 4
Specifications
MN/SDR54A.IOM
8.1.5 Adjacent Channel Interface Performance
The degradation in performance in terms of Eb/No shall not exceed 0.5 dB as a result of
adjacent channel interference caused by the presence of two simultaneous adjacent
channels. The channels are similar to the desired but up to 6 dBc higher in power. The
channel spacing varies as follows:
QPSK
± 1.3 x symbol clock
BPSK
± 1.3 x symbol clock
8.1.6 Frequency Stability
The frequency stability of the standard configuration is
± 15 ppm. The high-stability
option provides for a frequency stability of
± 0.5 ppm.
8.2
Digital Data Rates
The data rate (Table 8-3) for the demodulator is programmable in 1 bps steps. The symbol
rate is automatically calculated based on demodulation type and FEC coding. Any data
rate entered that exceeds data rate or symbol rate specifications will be rejected. The
demodulator is capable of supporting symbol rates from 9.6 kbps to 2.5 Ms/s. This
corresponds to data rates as follows:
Table 8-3. Digital Data Rates
Modulation
FEC
Data Rate
BPSK
1/2 Viterbi
4.8 to 1250 kbps
QPSK
1/2 Viterbi
9.6 to 2500 kbps
QPSK
3/4 Viterbi
14.4 to 3750 kbps
QPSK
7/8 Viterbi
16.8 to 4000 kbps
BPSK
1/2 Viterbi & Reed-Solomon
4.8 to 1138 kbps
QPSK
1/2 Viterbi & Reed-Solomon
9.6 to 2277 kbps
QPSK
3/4 Viterbi & Reed-Solomon 14.4 to 3416 kbps
QPSK
7/8 Viterbi & Reed-Solomon 16.8 to 3986 kbps
Note: For RS-232 data interface, maximum data rate = 64.0 kbps.
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