Comtech EF Data VMS v3.12.x Vipersat - Manual (Page 278)

Devices MN/22156, rev 12
4-60 VMS User Guide
FEC Type
The FEC Type setting is fixed at DVB-S2 for the Hub unit, and VersaFEC for
the Remote unit.
Roll Off
This parameter represents the Tx α (alpha) filter roll-off factor that dictates how
fast the spectral edges of the carrier are attenuated beyond the 3 dB bandwidth.
A lower value corresponds to a faster attenuation and thus less broadening of
the power spectrum density, and less satellite bandwidth required.
Can be set to 20% (default), 25%, or 35%.
ModCod
For the CDM-800, the ModCod is automatically selected; it is determined from
the QoS Group configuration (see the section “Network | WAN | QoS | Groups”
on page 4-28).
For the CDM-840, the ModCod is auto-configured in ACM mode when Link
Adaptation is Enabled. When ACM is not enabled, set this parameter manually.
Frequency
For the CDM-800, enter the center Frequency for the TDM outbound carrier.
• L-Band: 950.000–2150.000 MHz
• IF: 50.000–180.000 MHz
For the CDM-840, the Frequency is automatically managed by the VMS once
the unit has registered with the active server.
Symbol Rate
For the CDM-800, set the Symbol Rate.
Valid range is 1000.000–62000.000 ksps.
For the CDM-840, the Symbol Rate is automatically managed by the VMS once
the unit has registered with the active server.
Data Rate
This parameter appears for CDM-840 units only.
The Data Rate is auto-configured in ACM mode when Link Adaptation is
Enabled. When ACM is not enabled, set this parameter manually.
Valid range is 16–16000 kbps.