[linux-dvb] Re: New Nova-T errors

["Robert Schlabbach" <robert_s@gmx.net>]

From: "Edward Wildgoose" <Ed@Wildgooses.com>
> I have now got a new Nova-T to replace my full featured card, but
> unfortunately I'm getting a pretty scrambled picture which is
> "recognizable" as the original channel, but has huge multicoloured
> mpeg chunks all over it and lots of frame skipping (and big sound
> breakup) on most channels, and a big lag in sound on the few channels
> that the picture is OK.

Maybe your old full-featured card wasn't the problem after all, but your
signal ;)

> The Nova-T may be one of the newer designs and includes a remote control
> in the box.  The chips appear to be: Philips TDA10045H and Philips
TDM1316L

Except for the remote control this seems to be the card that Andrew has
developed the TDA1004x frontend driver on it...

> and I find that I need to use the tda1004x AND the ves1820 frontends
> to make it work

Humm, really? The VES1820 frontend really should not be needed.

> Can anyone please shine a little light on this!  I *suspect* that tuning
> is failing, for example the exact freq in Hz for BBC one is something
> like 505833330, but I have to enter this in dvbstream as "-f 505833", and
> I have an idea that this is not close enough for a good lock.

You have the wrong idea ;) The frontend module is using the 1/6th MHz step
size, and as such, 505833kHz ends up as being exactly 50583333.333 kHz
(plus oscillator offset) being programmed into the tuner PLL.

> The reason for the suspicion is that dvbtune is reporting fairly high
> error rates, and dvbstream just gives a single number, but it is in
> the 500 range.  Does this sound plausible?

It seems you simply have a weak signal. While you might try fiddling the
the frontend driver (Andrew used what ends up as a 36.166667 MHz oscillator
offset like the TechnoTrend driver does, which the DVB IF amplifier
downconverts to 5.166667 MHz, which is 166.667kHz off its centre frequency,
while I proposed using a 36 MHz oscillator offset, which would be
downconverted to 5 MHz, running the DVB IF amplifier right on centre, but
the tuner 130kHz off-centre), this may only make a marginal difference -
what you should really be looking into is improving the quality of the
signal you feed into the card...!

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



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