Teletext interface for digital storage medium having synthetic video generator

摘要

A teletext interface is coupled between a television receiver and a medium storing a plurality of digitally encoded signals each representing a selected text/graphics character intended for transmission as a corresponding synthetic video signal during the active scanning intervals of a television signal. The teletext interface includes a ROM for converting each of the digitally encoded signals to a teletext encoded signal representing a corresponding text/graphics character and apparatus for inserting the teletext encoded signals as a plurality of teletext formated data rows in successive teletext lines of the television signal. A television receiver including a built-in teletext decoder is responsive to the teletext formated data rows for displaying the selected text/graphics characters in a high quality form while a standard receiver is responsive to the synthetic video signal for displaying the characters in a poorer quality form.