METHOD AND DEVICE FOR TRANSMITTING ADDITIONAL DATA IN TELEVISION CHANNELS

摘要

In the terrestrial transmission network infrastructure, test lines and videotext are already carried mainly in the picture-free lines. Additional wireless services often fail as a result of the high cost of television studios and a shortage of frequencies. The present invention accordingly aims to make even fuller use of unused channel capacity in a TV channel for additional signals. At both the transmission and receiving ends, the signal pulses for additional video and audio data to be transmitted are formed from the FBAS useful signal by counting, evaluation and decision operations. The two signals are separated, digitised, stored, buffered and compressed at the transmission end before being superimposed on the useful signal. At the receiving end, following identical signal pulse generation, the same steps are executed in reverse order. The procedure can be carried out at the transmission end using additional equipment and at the receiving end by computer software or additional devices installed in the TV set. The procedure can be used for any additional picture and sound signals. A preferred special application is a communal picture broadcast in the manner of a slide demonstration.