[linux-dvb] TDA10046H very slow to tune

Hartmut Hackmann hartmut.hackmann at t-online.de
Tue Aug 15 21:11:08 CEST 2006


Hi, Barry

Barry Scott wrote:
> I'm noticing that the KWORLD DVB-T 220 with the
> TDA10046H tuner is very slow to tune 2 to 5 seconds.
> Cards like the AverMedia 771 tune in less then a second.
> 
> Is this a problem with the driver or the chip?
> 
> Barry
> 
This is not normal, do you use a recent version of driver and firmware?
The tuning takes about 0.5 seconds. With good signals, the TDA10046
locks within a second. You need to add the time for the DVB application
to fill its buffers and to find an I-frame. This is longer but the same
for all cards.
But: the first lock in a session (open dvb device) always takes longer
becase the chips need to recover from sleep mode, check and download the
firmware and determine some parameters. This is partly intention, partly
chip behaviour.

If the lock always takes longer, this might be due to poor signal quality.
Updating the firmware might help.
There also is one special issue with the TDA8275a silicon tuner: Due to
its pinciple, it is sensitive to strong transmitters on another channel.
Classic tuner "cans" handle this better.

Hartmut



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