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Discussion Starter · #1 ·
Need some help!


I am trying to connect my PC to my Philips 55 in. HDTV (55PP9701). I am using the Geforce2 ti and powerstrip to get the tv to display 1240x1024i. I can get it to work but the quality is horrible. All I really want to do is be able to surf the web, and maybe watch DVD. My tv can handle 800x600 native from the PC but for surfing it makes it hard since you can't see much of a web page without having to scroll.
 

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You are pushing your TV WAY over its abilities.


Your TV is rated for 1500 X 1080i maximum resolution. Which means it can do 750 by 540 non-interlaced. 800 by 600 would be okay, but anything beyond that you are going to get very fuzzy and unreadable images.


You should get a hi-res monitor (projector) capable of 1024 by 768 if you want to do serious Web Surfing on your TV.


Sorry...
 

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I am not familiar with the specs of that model but I would be very concerned that pushing a 540p/1080i monitor to 600p lines might cause damage.


But I'd be interested in other opinions here.


- Tom
 

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Discussion Starter · #4 ·
Thanks for the quick reply. If my monitor can handle 1500x1080i, wouldn't I be able to display 1240x1024i, or 1024x768i? The manual seems confusing. It says that is can handle 1500x1080i, but also says it can do SVGA (800x600) at 60hz. If it can do 800x600 progressive, I would think it could do 1600x1200i. RIGHT??
 

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Your TV most likely down (or up) sample all incoming signal to the resolution that it is most comfortable with. This is a pretty common solution that most RPTV's implement to handle variety of resolution issues.


So when your TV downsamples 800 by 600 (P) to native 750 by 540 (P), you probably don't notice much difference.


However, if you are downsampling 1240 by 1024 (i), there are a couple of issues that you run into.


First, it is probably a resolution that your TV cannot handle well. You will have much more success if you are going in multiples of 750 by 540.


Second, you are interlacing. No matter what you do, interlaced text is not going to be comparable to progressive text. It makes it unreadable (especially when fonts are getting smaller).


Your monitor is probably going to look its best if you can set your resolution on the PC to ouput 750 by 540P or 1500 by 1080I.
 

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Your 1240x1024i looks like garbage for three reasons: it produces pixels not nearly as square as your PC expects; it is an interlaced mode with a fairly slow scan rate (30 frames per second... 43-1/2 fps was once considered the minimum for a 1024x768 computer display even with a special long-persistence monitor); and it does not match one of your TV's built-in scan rates (so the TV has trouble syncing with it and probably screws up convergence).


I don't like to contradict all of my friends here, but I have a different view of your situation. I went and reviewed the specs for your TV (55PP9701) (nice one, BTW... I envy you). It is clear that Philips built it to work with 3 display scan rates: 480p, 540p/1080i, and 600p (all at 60Hz). (540p and 1080i are the same. Actually, you could fake up 960i or 1200i modes on this device and they would work fine.) It probably does NOT work with other scan rates (if it did, Philips would say so), but it might possibly handle NTSC 240p/480i as well. (The TV has a line doubler that converts incoming 480i signal to 480p, so even though it has 480i inputs, it may not be able to scan at 240p/480i.)


[Note to nitpickers: I'm simplifying things a little here. I know about 525, 262-1/2, 29.97, and that sort of thing.]


Now, it is very, very likely that your Philips is a "multiple fixed-frequency monitor," *not* a sync-to-anything monitor. So the picture will only look good at 480p, 540p/1080i, and 600p, because those are the only the rates it is built to lock onto. It's very likely that you can only get the convergence right for those scan rates. Misconvergence will make the picture look like doodoo immediately.


For your unit, Philips advertises 1500 pixels horizontal resolution. That claim may be somewhat inflated, but the horizontal resolution will be about the same at all scan rates. However, using more (horizontal) pixels won't change the actual size of the picture, so if you were in 600p mode and actually shoved ~1500 pixels into each line, they'd be skinny ones, and computer text would be hard to read, because (common) computers assume that all pixels are "square" (equal width and height). For a 16x9, 600p scan you would want 1064 pixels on each line to get square pixels (actually 1067, but most VGA cards force the horz. resolution to be a multiple of 8 pixels).


I DON'T KNOW IF YOUR TV SHOWS VGA SIGNALS ACROSS THE WHOLE SCREEN, OR SCALES/SIDEBOXES THEM INTO A 4x3 PATCH. IF IT CONFINES THEM TO 4x3 PATCH, ADJUST YOUR HORIZONTAL PIXEL COUNT APPROPRIATELY.


In either case, to get a good looking computer display on your TV you should use ONE OF 480p (480x854 for widescreen), 540p (540x960 for widescreen), or 600p (600x1064 for widescreen). Obviously the 600p display is what you want if you can get it set up.


You can't get enough horizontal pixels to make any interlaced (960i/1080i/1200i) mode look perfect, but if you insist on using such a mode, I suggest you try 960i... 960x1496 will come as close as you can to square pixels using your TV's claimed capabilities (close enough for gov't work, I think). (I predict some horizontal blurring, probably acceptable if you use large fonts--you won't notice it much in graphic images). Then reduce the room lighting as much as possible (down to nil if you can, except for a 6500K backlight behind the TV). The darker the room, the less flicker you will notice from the interlaced scan. I guarantee that text will flicker a lot on a 30fps interlaced scan if you have a lot of ambient light.
 
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