> From: [email protected]
> To: [email protected]
> Date: Thu, 18 Feb 2010 19:28:58 -0500
> Subject: Re: [ivtv-users] hvr-1600, frame CRC mismatch - incomplete frame
>
> On Thu, 2010-02-18 at 10:33 -0500, Kyle Lil wrote:
> >
> >
>
> > OK, so I built an attenuator with a potentiometer in position Z2 for
> > the circuit diagram you sent me. I'm sure there are probably a whole
> > slew of problems this could introduce (especially since I did not put
> > a pot in position Z1 also), but I wanted to be able to easily look at
> > the various attenuation levels (and I don't have a soldering iron at
> > home, just at work). What I found was that the glitches are still
> > apparent even when I turn the potentiometer to a level that make my
> > cable box OOB AGC go to >30% (which it now rates as "fair" instead of
> > "good"). The cable box and HVR-1600 are at the output of the same
> > splitter, which is after (downstream of) the adjustable attenuator I
> > built. The way I constructed the circuit, I could not provide enough
> > attenuation to cause the tuner to lose station lock, but with the
> > maximum attenuation (~-14dB from attenuator + -6dB from the two
> > splitters between the HVR-1600 and the wall) I could achieve, the
> > glitch rate was the same (or maybe slightly higher).
>
> Hmmm. Crud, io suspect there must be something else going on.
>
> My next guess is that the HVR-1600's AGC is responding too quickly (or
> too slowly?) to variations in the incoming signal.
>
> I'll have to think about it though.
>
> Since I have a somewhat similar condition on two ATSC stations, I'll
> work up a debug patch for the s5h1409 driver that reports some more
> stats from the CX24227. I have never used the additional statistics
> registers before and I don't have much faith in the documentation I
> have, so I'm not sure if they work or will be useful. We'll see. I
> won't be able to do anything until Saturday night at the earliest.
>
>
>
> >
> >
> > I will try to build an attenuator today that is able to reduce the
> > signal all the way down to an un-lockable level. Is it possible that
> > the HVR-1600 is so sensitive that a signal level my cable box rates as
> > only fair is still too large for it?
>
> I would doubt it, but it still could be the case.
>
> I think if we can get more stats from the CX24227 chip, we may get more
> insight as to what might be wrong.
>
> Regards,
> Andy
>
>
>
>
> _______________________________________________
> ivtv-users mailing list
> [email protected]
> http://ivtvdriver.org/mailman/listinfo/ivtv-users
That sounds great, Andy. Thanks so much for spending the time to get to the
bottom of this.
I built the more powerful attenuator and essentially what I see is that the
error rate increases dramatically as the gain approaches zero.
Please let me know if you are able to get the CX24227 to report more statistics
and have some tests you'd like me to run on my end.
Kyle
_________________________________________________________________
Hotmail: Powerful Free email with security by Microsoft.
http://clk.atdmt.com/GBL/go/201469230/direct/01/_______________________________________________
ivtv-users mailing list
[email protected]
http://ivtvdriver.org/mailman/listinfo/ivtv-users
