SMD 989
– User Manual
Page 46 (105)
By clicking the
icon, the recommended symbol rate will be inserted into the symbol rate.
Turbo PSK modulation includes many modulation types and FEC code combinations. Figure 39
shows code rates available for the Turbo PSK modulation mode and a representation of the
settings for TurboPSK single mode modulation in the dropdown menu.
Code Rate
QPSK
8PSK
16 QAM
½
X
2/3
X
X
¾
X
X
X
3/4 (2.05)
X
3/4 2.10 4/5
X
5/6
X
X
7/8
X
8/9
X
Figure 39 Advanced Modulation Turbo PSK
modes and code rates
The remaining settings include (Bold indicates
default):
Spectral Inversion
-
Normal
-
Inverted
Description:
Determines whether the spectrum is inverted or normal.
Note:
When the SMD 920 L-Band option is installed, the default spectral inversion is
inverted as the upconverter will invert. Setting the output to Inverted will give a normal
output from the upconverter. This is shown in the RF Output status for Spectral Inversion.
Alpha Filter Rolloff
-
0.35
-
0.25
-
0.20
-
0.15
-
0.10
-
0.05
Description:
The filter rolloff
is known as the Alpha coefficient (α). The smaller the α, the
less bandwidth will be required on the satellite.
Advanced Turbo Modulation Settings
The TurboPSK modulation mode provides several advanced features which may be enabled or
selected for use. The Advanced section provides settings for Sync Byte Deletion, Reduced
Latency, and PRBS.
