EXPERIMENTS ON DATA BROADCASTING IN A TELEVISION CHANNEL.

Two teletext systems were developed in Europe: UK teletext (Ceefax/Oracle) and French Antiope. The latter is a special application of the universal DIDON data broadcasting system. The introduction of these new services is faced with the problem of compatibility with the existing television system. An investigation of the performance of UK teletext and DIDON thus constitutes the aim of trials undertaken by the research and development division of the Swiss PTT. After a description of the data broadcasting systems, the equipment and the measurement zones, the measuring techniques and field trials with UK teletext and DIDON are discussed. The most significant results, valid in the precise context of the experiments, and conclusions of a more general range are reported.