[linux-dvb] Re: DVB-C driver (Re: More thoughts on coldbootdriver crash)

[Ragnar Sundblad <ragge@nada.kth.se>]

--On den 5 januari 2003 07:00 -0500 JosceJ@netscape.net wrote:

>> Removing zigzag completely seems a bad idea as it looks like
>> something needs a reset every now and then, my second card lost sync for
>> example an hour ago and still is not synced.  Need to get zigzag or at
>> least resetting the frontend back.
>
> This is one of the problems I am having. With zigzag enabled or disabled
> it sometimes looses lock and doesn't seem to be able to get it again. But
> this happens both with zigzag and without zigzag. I was wondering
> maybe after loosing sync a few times the driver could reset it self
> as you said.

Maybe you could find out what really happens when you drop
lock and try to fix that?

With my (yes, broken, yada yada) DVB-T card I could get a bad
lock even when tuned slightly off, which mean that if
the zigzagger thought it had a signal drop it could start to
zigzag, find the carrier on a less than optimal frequency,
and stay happy with that.

When I turned the zigzagging off the demodulator handled any
deviations just fine (if there were any), and I haven't seen
any problems because of the lack of zigzagging.

My experience with this is obviously very limited, but I am
still not convinced that zigzagging is necessarily the right
thing to try with DVB-T when you have the exact frequencies
and with a frontend that does minor corrections automatically.
Maybe one could change it to no try to retune to a frequency
that would only make the demodulator do its best to correct it.
For other situations I have no idea.

/ragge




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