HDTV
(High Definition TV )

HDTV (High Definition Television) defines TV image formats with a higher picture quality than standard TV (SDTV). A standard TV picture is composed of 576 active lines, HD provides an image with a format of either 720 or 1080 active lines on the screen. Ultra High Definition TV (UHD) provides either 2160 or 4320 active lines.

A standard TV picture is send as two interlaced frames. One frame is build up from all the even lines followed by a frame build from all the uneven lines. HDTV has two different ways to build the picture, an interlaced frame 50 times a second resulting in a complete interlaced image twenty five times a second or a progressively scanned complete picture fifty times a second. HDTV is also always formatted as 16:9, which means that the size of the picture is much broader compared to its height than a conventional standard TV format of 4:3. Hence, for equal picture resolution HDTV needs proportionately a greater number of pixels per line than for the conventional 4:3 format.

The various flavours of HDTV and Ultra High Definition (UHD TV) are given in the table below.