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SDM-300L3 Satellite Modem
Specifications
Using vector analysis of the constellation pattern, QPSK represents a symbol with the
carrier phase angle at 45°, 135°, 225°, or 315°. The 1/2, 3/4, and 7/8 rates provide the
desired input/output bit rates.
14.11.3
OQPSK Decoding (Optional)
The demodulator PCB converts the transmitted baseband data into a modulated OQPSK
carrier within the same parameters as QPSK.
The OQPSK modulation is mainly different from QPSK by offsetting the I and Q channel
modulation signals. This offset prevents the RF envelope from going through zero. Under
certain conditions, this may allow less back-off in the High Power Amplifier (HPA)
system. The 1/1, 1/2, 3/4, and 7/8 rates encoded provide the desired input/output bit rates.
14.11.4
8-PSK Decoding
The demodulator converts transmitted baseband data into modulated 8-PSK carrier at the
following parameters:
Using vector analysis of the constellation pattern, 8-PSK represents a symbol with carrier
phase angles at 22.5°, 67.5°, 112.5°, 157.5°, 202.5°, 247.5°, 292.5°, and 337.5°. The rate
encoding provides the desired input/output bit rates.
Code Rate
Symbols/Bit
1/1
1
1/2
2
3/4
1.5
7/8
1.143
Code Rate
Symbols/Bit
1/1
1
1/2
2
3/4
1.333
7/8
1.143
Code Rate
Symbol/Bit
2/3
1.5
3/4
1.333
14–30
Bits/Hz
2
1
1.33
1.75
Bits/Hz
2
1
1.5
1.75
Bit/s Hz
2
2.25
Revision 0
MN/SDM300L3.IOM
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