[linux-dvb] [PATCH] Tuner calibration for some Nova-T devices

[José Oliver Segura]

       Hi Treza,

       thanks a lot for the patch. I've been able only to do some
quick tests (hope to be able to perform some more this afternoon), and
I've found that this patch seems to give some improvements (great!),
but some other "strange" effects still appear (thus, I start to think
that they have no relation with signal strength). I wrote a little
program that performs a tzap for each of the channels in
channels.conf, gets output about signal strenght, ber, unc, etc. and
writes out a summary. Below you could find the compared results (pre
and post patch):

[root at mediacenter ~]# tail -11 output.prepatch.signal.test
Summary statistics:
Frequency       Signal  Ber             Unc
=========       ======  ========        ========
514000000       a151    00000000        00000001
570000000       96f9    00000000        00000000
794000000       8308    00000000        00000001
818000000       7539    00193640        00000fae
834000000       79b8    00044993        00000bd6
842000000       7b72    00004394        00000009
850000000       79ce    00051580        000023f1
858000000       7843    000694ee        00001d2b

[root at mediacenter ~]# tail -11 output.afterpatch.signal.test
Summary statistics:
Frequency       Signal  Ber             Unc
=========       ======  ========        ========
514000000       9ae6    00000000        00000000
570000000       9a0e    00000000        00000001
794000000       940e    00000000        00000000
818000000       734b    0003d40d        000026e8
834000000       8a8e    00000000        00000000
842000000       8c8f    00000000        00000000
850000000       843d    0000002c        00000000
858000000       8154    000000df        00000001


       As can be seen, output for post-patch looks better related to
Ber/Unc, despite the fact that some of the signal strenghts are not
improved (but others are, that looks good). There are still problems
with the 818000000 Hz band (note the high Ber/Unc), but I think that
these problems doesn't have relation with signal strenght, as long as
with the same signal strenght I can get better or worse results (just
loop tzapping / ^C some channel in this frequency causes the increase
of BER/UNC numbers). Could it be related to some management issue in
the frontend instead of some signal strenght problem?

       I'll try to perform some more tests this afternoon (maybe also
try the SPURCHECK flag) and post results. If any of you is interested
in some specific number/information/log, just let me know and I'll do
my best to get them.

       Best,
       Jose

On 12/15/06, treza at chez.com <treza at chez.com> wrote:
> Hi folks
>
> Here is a patch for Hauppage Nova-T-Stick and Nova-T-500 users.
> It sets the MT2060 IF1 frequency according to the
> calibration values stored in the EEPROM.
>
> It is supposed to enhance the signal quality, but, hey,
> there is no guarantee.
> Feedbacks would be much appreciated, to know whether it
> deserves being applied.
>
> For those who have a MT2060 based device, very low signal
> levels and feel _very_ lucky,
> they can also activate MT2060_SPURCHECK in the mt2060_priv.h
> file. At worst case it will change nothing.
>
> Patrick, the (dib0700_state.mt2060_if1 field in dib0700.h
> becomes useless with this patch, is it right or shall I move
> the code to the "frontend_attach" functions ?)
>
> Signed-off-by: Olivier DANET <odanet at caramail.com>