[rdkent]

Steve:
Without writing a book - a tv picture is made up of a lot of lines scanning across the screen. The set of line that make up a complete image are called a frame. Resolution is defined by the number of horizontal lines displayed to make up each frame. Standare tv resolution uses 480 lines for each frame. HDTV uses either 720 or 1080 lines to make each frame. The "i" refers to interlacing. That refers to whether each of those frames contains all the lines of image or every other line. Interlaced signals take every other line from 2 frames, each lasting 1/60th of a second, and combine them into one frame lasting 1/30th of a second. Tricks your eye into thinking it's seeing twice the resolution actually displayed. In non-interlaced video, called progressive scan (or "p") frames are displayed every 1/60 second containing all of the lines of video. Most HDTV's now are 720p or 1080i, and 1080p is becoming more common. For the average viewer (like me) it is hard to really see the difference between the 3. Kind of like my hearing inability to really appreciate the difference between a $500 stereo system and a $5000 system. There is no doubt, however, that you can really see the difference between standard tv and HDTV. Hope this helps without TOO much detail.

Ron