VIDEO AND DATA CO-CHANNEL COMMUNICATION SYSTEM

摘要

In the present invention, ancillary data is modulated onto a carrier frequency which is within a low energy density portion of a frequency band of a video signal, and the modulated carrier data (44) is combined with the video signal (46) so that the modulated carrier is either in an active video region or in an overscan region of the video signal. The ancillary data may be spread over several frequencies and summed at the output of a decoder to enhance the legibility of the ancillary data at the output of the decoder. Frequencystepping may be used to add the ancillary data at ones of a plurality of selected frequencies within the frequency band of the video signal. Then ancillary data may be hierarchically apportioned between respective uniquely specified sequential segments corresponding to many distribution points of the video signal.