Compatible wide-screen teletext for use with HDTV systems

The display characteristics of current 4:3 aspect ratio television systems limit typical teletext displays to 24 rows of 40 columns. Due to the restricted transmission capacity and the need for affordable decoders, enhanced forms of teletext have not been brought into service. Now, the establishment of HDTV broadcasting services offering higher resolution and displays of wider aspect ratio coupled with adequate transmission capacity for auxiliary services will provide opportunities to overcome these limitations of current teletext systems. In the change from conventional-definition television to HDTV, however, compatibility between existing 4:3 teletext and future 16:9 HDTV teletext service needs to be given due consideration. A first system approach presenting the so-called "side-panel" solution as one of the proposals under discussion for a future HDTB teletext is discussed