Behandlingssystem with alternerande underbaervaog Foer vidskaermtelevisionssignal with foerstorad upploesningsfoermaoga

An NTSC compatible EDTV wide screen system encodes and decodes a television signal which comprises: (1) a main signal consisting of an NTSC signal N in standard format and in which low frequency side area information has been compressed in its upper scanning area; (2) a time expanded high frequency picture information component X for the side areas; and (3) an expanded high frequency picture information component Z for horizontal luminance. The components 2 and 3 modulate an alternating subcarrier ASC which has a different frequency to the colour subcarrier within the frequency band which is used by the colour picture information.