Comtech EF Data CDM-710 Installation And Operation Manual page 121

CDM-710/L Broadcast Satellite Modem
Front Panel Operation
(Config:) Tx:  Mod  Type
Use the arrow keys to select the Transmit Modulation Type as QPSK, 8PSK,
 
16QAM, 16APSK, or 32APSK. Press ENTER.
The selections are mode-dependant:
• QPSK – DVB-S and DBVB-S2
• 8PSK – DVB-S2 and DVB-DSNG
• 16QAM – DVB-DSNG
• 16APSK – DVB-S2
• 32APSK – DVB-S2
(Config:) Tx:  Mod  Inv
Use the arrow keys to select Normal or Invert. Press ENTER.
 
(Config:) Tx:  Mod 
The Tx Alpha Rolloff (α) setting dictates how fast the spectral edges of the carrier
are attenuated beyond the 3 dB bandwidth. With 20% rolloff the edge falls off
more quickly than with 25% and 35%.
The default Tx Alpha Rolloff (α) setting is 20%. Whenever the Mode is changed,
(α) reverts to 20%. Use the   arrow keys to otherwise select 25% or 35%.
Press ENTER.
Tx Mod: QPSK 8PSK 16QAM 16APSK
32APSK
Tx Spectrum: Normal
Inverted
α
Tx (α) Rolloff %: 20 25
35
7–15
MN/CDM710.IOM
Revision 12
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