By MICHAEL MILLER
Buying a TV Set That's Right for HDTV
Let's start with HDTV reproduction. There are three primary formats of HDTV in use today: 720p, 1080i, and 1080p. These numbers refer to the number of scan lines in the picture, and whether the picture is interlaced or progressive scan. In comparison, standard definition television is 480i -- only 480 scan lines, interlaced.
Theoretically, progressive scanning is better than interlaced, in that the entire set of scan lines appears onscreen at the same time. With interlaced scanning, only half the scan lines appear at once, creating a picture that interlaces two halves of the total picture. However, when the number of scan lines is so high, most viewers can't tell the difference between 720 lines progressive scan or 1080 lines interlaced. The quality is so much better than standard definition, they both look great.
You need a set that can reproduce a minimum of 720p HDTV programming. This is the most common type of HDTV set sold today. Some higher-end sets, however, can reproduce up to a 1080p picture, which is even higher resolution than a 720p set. These sets typically come with a higher price point than the 720p sets.
So, should you go with a 720p or a 1080p set? This is where it starts to get a bit confusing. Most HDTV broadcasts today are either 720p or 1080i. There are no 1080p broadcasts, although the new high definition HD DVD and Blu-ray DVD formats promise 1080p resolution. So a 1080p TV isn't technically necessary, although it's nice to have. And whichever resolution set you buy, the TV's internal electronics will either convert lower-resolution signals to the set's native resolution or convert higher-resolution signals accordingly. For example, if you have a 720p display and are watching a 1080i program, the TV converts the 1080i signal to fit the 720p display. If you have a 1080p display and are watching a 720p program, the TV converts the 720p signal to fit the 1080p display. It's all done automatically, and the conversion is virtually unnoticeable to the viewer.
Michael Miller is a writer and commentator on technology and digital lifestyle topics.
