PALplus
PALplus is a variant of the PAL television standard introduced in 1991 that uses a 16:9 aspect ratio and was developed for terrestrial networks. PALplus's 16:9 format is compatible with PAL, but should not be confused with conventional television broadcasts that are broadcast in this aspect ratio.
PALplus has less interference from chrominance and luminance and makes optimum use of the display area of a 16:9 screen. With PALplus, additional signals and information are transmitted in the vertical blanking interval in line 23, allowing a perfect picture reconstruction in 16:9 format without corresponding restrictions in the vertical, as with conventional PAL, where the picture height in a 16:9 broadcast consists of only 432 lines. This helper signal from line 23 is decoded in a special decoder and ensures that in PALplus reception the receiver displays 576 visible lines.