HDTV
Key features of HDTV’s
All digital displays make their pictures up using pixels, where the more pixels a screen has, the better and the image. This is called the screen resolution and it is well worth having a basic knowledge of the resolution formats if you want to make the most informed choice when purchasing your new HD kit.
The two formats for High-Definition are 720p and 1080i. The 1080i format contains 1080 lines of image information, which is produced using the interlaced (hence the 'i') system. This means the pictures on your television are produced in two separate 'sweeps', with the odd lines (1, 3, 5, 7 etc) created during the first sweep and the even lines (2, 4, 6, 8 etc) created during the second. The sweeps are so quick, however, that the human eye sees only one complete image.
The 720p format, while having fewer lines of image information, uses progressive-scan technology (hence the 'p'), where all the lines are created at once, as opposed to two separate sweeps. This ensures an exceptionally smooth image, which is often preferable to 1080i for fast-moving footage (again, such as football).
But as technology improves and with the launch of High-Definition (which is shot in widescreen format), the only real choice is to opt for a widescreen TV when making your next purchase. Almost all large (28-inch and above) screens are now only available in widescreen format though, making it an easy decision to make!
Where the image on your screen is created by two 'sweeps', where the odd lines are produced in the first sweep and the even lines in the second sweep, with the two sweeps interlaced to create one picture. One of the key High-Definition formats, 1080i, uses interlacing technology.
