By Joel Johnson..:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />

Illustration by Fran Saa

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There is a magic time in the evolution of a consumer electronics product when it descends from the realm of fantasy into reality because of a new combination of price, availability and choice. For high-definition TV, that time is now. Great HDTVs can now be found for under $1000--and even many big, 42-in. sets are under $2000. There is finally plenty of content available to watch--popular prime time TV shows and many sporting events are broadcast in HD. But the terminology and specifications for high-definition television are as confusing as ever. Wouldn't it be great if someone explained all the jargon in plain English and gave you the information you need to find and set up a great HDTV? We thought so, too.

WHAT IS HIGH-DEFINITION TELEVISION, REALLY?
It's important to remember that there are two sides to HDTV. There is such a rush these days to buy a high-definition display that many people don't consider where their hi-def content will come from. If you have one without the other, you aren't getting a true HD experience.

High-definition television is as much about the signal as it is the set. For years, analog standard-definition television (SDTV) has been transmitted in a format known as 480i. This means that 480 horizontal lines of pixels (or picture elements--the tiny little dots that compose the image on your TV screen) are broadcast interlaced (odd-numbered lines painted in 1/60 second, then even-numbered lines painted in the following 1/60 second). The alternating lines whiz by so fast that, to the human eye, they blend together.

Computer monitors, on the other hand, paint their screens using progressive scan--every line is painted in every frame. Since modern HDTV is an evolution of both television-broadcast and monitor technology, we ended up with a multitude of broadcast standards including 1080i (interlaced), 720p (progressive) and the emerging 1080p.

HD signals can be broadcast in any of these formats. Luckily, the signal's format doesn't matter much to the TV viewer because hi-def sets use digital processing and can adapt to most formats. What matters is the resolution that each set ends up displaying. And a true HDTV can display more lines of resolution than a conventional analog SDTV. That means more pixels, which means a more detailed picture--right down to the mud on the faces of NFL linemen and the crow's-feet on the faces on Desperate Housewives. In fact, TVs that display video at the highest HD resolution (1080p) have over six times as many pixels as SDTV. So why don't all the new-generation sets displayed in stores look spectacular? Usually, it's for one of two reasons. First, not every fancy new TV displays a hi-def image. Enhanced-definition televisions (EDTVs) are the middle ground of the digital television world, displaying images that are superior to SDTV, but converting true HD signals down to a lower resolution.

Second, many stores aren't plugging their HDTVs into a hi-def source. Many sets are playing DVDs, which are only marginally better than standard definition.

Which raises the question: How can I tell if a TV is an HDTV? Essentially, it needs to be able to display at least 720 progressive lines or 1080 interlaced lines of pixels. Many manufacturers have started to list the resolution of their sets in "width by height in pixels." For instance: "WXGA (1366 x 768 pixels)." Most HDTVs have a 16:9 widescreen aspect ratio (as opposed to the 4:3 screens common to SDTV), so the 1366 in the example above refers to the number of vertical rows of pixels, while the 768 refers to the horizontal lines. Since 768 is higher than 720, the set has more than enough lines to display HDTV "natively," or without downconverting the signal. So if you have one question to ask yourself (or a salesperson), it's this: Does the TV I want to buy display high-definition natively?