When I input 1080p from the HTPC to my 1209s, I find several faint vertical lines over the left side of the image. The lines are more obvious in brighter scenes. Is it the raster ringing? There is no problem in 1080i. How can I get rid of these lines?
I read from the official forum of crystalio, the 'raster ringing' is due to the extreme short retrace time required for this sort of resolution (1080p). Does it mean the 'ringing' is inevitable in 1080p and phase the video to the right is the only solution. Anyone with the same experience in using 1080p? In fact, I've changed all the cables and display card from ATI9600 to Matrox P650.
I think all 9" CRT including 1209s are well coped with 1080p. The vertical refresh rate of 1080p is only 60Hz .
Some "ringing" is inevitable. It's caused by the fast retrace needed for 1080P "strumming" the resonant circuit made up of the horizontal deflection yoke cables and the interwinding capacitance of the deflection yoke.
The darker bands are where the electron beam sweep speed increases and the lighter ones where the beam slows.
This will always show when you have reduced the back porch too far. That's the reason the back porch is way too wide for most of our PJs - it has to accommodate the worst/cheapest display devices out there.
Our PJs use far higher class and better designed circuitry, so the porches can be safely reduced. I reduce mine until the ringing (as seen in Kal's photo) is JUST discernable on a plain white scene when I am looking for it. It is therefore never seen in real material.
I had to leave my back porch at around the powerstrip default for a 1280x720 HDTV signal - that is, around 250. This gave the raster enough time to stabilize. Front porch is in the low single digits.
I then shifted the raster over and then used H-phase to shift the image in the other direction.
So now my Horiz raster shift in the 70-80 range and H-phase is in the 20-30 range (instead of both being around 50). Oh well. I guess it'll run a bit hotter...
There other two other options however:
1. NOT maximize my phosphor usage like I do and have large front/back porches such that everything is perfectly centered and H-phase and H raster shift are both around 50. (Not an option).
2. Do #1 but then increase the max width pot (P2 on the SMPS) such that the image area uses a good amount of phosphor width again. The raster would extend off the CRT surface on the left and right sides so blanking should be used.
Hmmm.... I wonder which way is worse for the PJ... increasing horiz deflection or using a lot of raster shift... I'll start a new thread with pictures...
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