...As of February 2009 all TV signals will be digital so I would not be concerned that much with the quality of standard quality signal. Cheers.
We're talking about two different things here. The digital transition that will occur in February is a move from analogue to digital
transmission, not from standard to high
definition signal quality.
What this means is that folks who are still using an old television set that is not equipped to display a digital signal will essentially see nothing but snow. But for those of us with digital televisions, the inherent quality of the picture on a standard definition channel will remain unchanged, kinda crappy.
The difference between standard and high definition is a matter of number of horizontal lines being "painted" to create the image you see. It's sorta similar to the notion of pixels on a computer screen. 480/720/1080, those are the most typical numbers of lines we'll see drawn on screen -- though there are others, too.
Standard definition is 480 lines. The low number of horizontal lines of data means that, for each line drawn, the line is required to present the image in larger chunks over the area of your screen. t's got to take fewer pieces of the image and spread them over a greater area. When you now look at high definition --1080 -- the number of lines of data drawn is that much greater. Each line is only responsible for a much smaller amount of image area to present. More lines equals finer image detail.
The "i" or "p" simply refers to the manner in which the lines are presented/drawn on the screen. Interlaced (i) images are presented as two sets of 540 lines (540 is for 1080, divide any other number by two to get its respective halves). The lines are drawn in an alternating sequence -- 1,3,5,...then 2,4,6... so quickly that our eyes can't see them being drawn, but that's the essential idea behind interlacing. The progressive image paints the lines in sequence -- 1,2,3,4... Somehow this results in higher image detail. Not sure on the guts of that one, though it may have to do with processor power. You can google the idea and find many discussions that do a much better job than I can of explaining...
As for lcd vs. plasma. As has been mentioned, lcd is backlit -- it uses light to create its colors and tones. So what this means for your picture is that it is using white light to create black tones (black/white is expressed as "tones" not colors. Colors are red, green, blue). Anyhow, making black from white is kinda counterintuitive when you stop to think about it. Each pixel on an lcd starts as white light, but in order to create black they combine all of the colors in full density to block the light and thereby render a "black" for you. While they've made great leaps in the quality of the black that lcd screens can render, there may still be this factor/notion to "overcome." At least it was a factor two years ago when I bought my plasma.
This is why lcd's will advertise their contrast value. The higher contrast ratio should give a "snappier" picture as the unit will have finer degrees/steps of value as it goes from white to its final black value. The funky thing about this is that I don't believe that there's an industry standard for how the contrast ratio is calculated and thus expressed. So you'd do well to understand how each respective manufacturer is calculating this value when comparing different brands.
I went with plasma only because my fussy eyes didn't like the quality of the black tones on lcd's at the time. Maybe this isn't, or is not as much of, an issue any longer. I dunno, I'm not doing any research on this stuff right now...I'm very happy with my Panasonic plasma. And it "only" does 1080i.
As has been mentioned, plasma's draw more power and will reach higher operating temps. Not the most green choice I suppose. Not like it's a huge power draw, but it's more than a similarly sized lcd. If you live in a small space without a/c I guess the heat that such a device might give off could be an issue.
Apologies for the length of the post...
Thanks!
