On Thu, Sep 24, 2009 at 02:55:42PM -0400, Michael Krufky wrote:
> On Tue, Sep 22, 2009 at 5:09 PM, <spam@xxxxxxxxxxxxxxxxx> wrote:
> >
> > Switches IF AGC control via GPIO 21 of the saa7134. Improves DTV reception and
> > FM radio reception.
> >
> > Signed-off-by: Henk.Vergonet@xxxxxxxxx
>
> Reviewed-by: Michael Krufky <mkrufky@xxxxxxxxxxxxxx>
>
> Henk,
>
> This is *very* interesting... Have you taken a scope to the board to
> measure AGC interference? This seems to be *very* similar to
> Hauppauge's design for the HVR1120 and HVR1150 boards, which are
> actually *not* based on any reference design.
>
> I have no problems with this patch, but I would be interested to hear
> that you can prove it is actually needed by using a scope. If you
> don't have a scope, I understand.... but this certainly peaks my
> interest.
>
> Do you have schematics of that board?
>
> Regards,
>
> Mike Krufky
>
One note: I have tested the tda18271 signedness fixes in the debug
repository. This is a big improvement in reception.
Based on the latest testing with all the fixes I would say that
switching the AGC line via gpio is not needed and leaving it at 0 gives
the best results.
(This is purely based on SNR and BER readings from tzap)
So I would recomend: leaving config at zero.
static struct tda18271_config zolid_tda18271_config = {
.std_map = &zolid_tda18271_std_map,
.gate = TDA18271_GATE_ANALOG,
- .config = 3,
+// .config = 3,
.output_opt = TDA18271_OUTPUT_LT_OFF,
};
Regards,
Henk
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