[linux-dvb] dvb-s2 parameters - rolloff & pilot

Steven Toth stoth at linuxtv.org
Fri Dec 14 18:24:34 CET 2007


Igor wrote:
> Hi
> 
> can somebody to explain when need switch on or switch off this options ?
> 
> dvb-s2 initial pilot on/off
> 0 OFF
> 1 ON
> 
> dvb-s2 rolloff
> 0=0.20 (DVB-S2)
> 1=0.25 (DVB-S2)
> 2=0.35 (DVB-S2/DVB-S)

As far as I know, for all existing European satellites, you do not need 
to care about these parameters with the HVR4000 driver.

Pilot mode is fully automatic within the Linux driver (but slower 
because it involves a retune). I think the default Roll Off in the 
driver is 0.25, and I've not been made aware of any satellites that use 
0.20 or 0.35 (yet). Should you find a satellite which uses the 
non-default Roll Off, chances are the demod would not lock.

Regards,

- Steve



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