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
