[linux-dvb] ves1820 FEC off? EN 300 468 -> cable:has inner fec, on implementing

Robert Schlabbach robert_s at gmx.net
Mon Jul 25 14:08:59 CEST 2005


From: "thomas schorpp" <t.schorpp at gmx.de>
> in 429 the framing shows only outer r-s fec.
> the latest 468 standard says we HAVE inner fec(!)

No, it just defines a way to indicate an inner FEC method through the DVB
Service Information. But since there is no inner FEC method defined for the
DVB-C transmission standard, the only possible value you can use is:

> Table 35: Inner FEC scheme
> 1111 no conv. coding
>
> i'll implement this in the driver until weekend

What do you want to implement? I suggest you start by examining the DVB
Service Information you receive (try e.g. dvbsnoop). I'm 99.99% sure you'll
find "no conv. coding" indicated in your cable delivery system descriptors.

> -if- someone gets me programming registers and values or a full
> datasheet, theres no on the web, or i try using the ves1x93 data...

The VES1820 is a demodulator for the DVB-C standard and thus has no inner
FEC (Viterbi) decoder. The circuits for this are simply not there, period.
Stop thinking about inner FEC, it is definitely _not_ the problem you are
facing.

Regards,
--
Robert Schlabbach
e-mail: robert_s at gmx.net
Berlin, Germany





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