Method and apparatus for displaying on a raster-scanned display system, e.g. a CRT screen, messages transmitted by a television-like signal and comprising repeating elements

摘要

This method consists in detecting in the transmitted signal a binary value code (OO) determining the start of the repetition of a message element on the display device (18). The corresponding code is permanently stored in a fixed register (57) whose content is compared with the current code of the message elements. In the event of equality, a comparator causes inhibition of a time-base circuit (43) ensuring the successive processing of the codes of the message elements. The inhibiting of the time-base circuit is suppressed by counting down the number of repetitions required or by the line synchronising signal for the tube (18). This method permits considerable reduction in the capacity of the page memory (22) in which the message elements of each message page to be displayed are stored. Application in teletext transmission networks. IMAGE