Spread spectrum digital data transmission over TV video
AssigneeA. C. Nielsen Company
InventorsJean P. DeJean, Daozheng Lu, Robert Weissman
Life of this patent
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Abstract
A co-channel communication system allows transmission of one or more data signals in an active or visible portion of a video raster in a manner that is imperceptible to a viewer. More particularly, the data signal is transmitted over a preselected active video lines of a video raster. In order to reduce the perceptibility of the data signal, the video lines over which the data signal is transmitted is varied according to a random sequence. In an alternate embodiment, the data is also modulated at relatively low modulation levels, for example, by converting the data signal to a spread spectrum signal.
Claims17
A co-channel communication system for transmitting one or more data signals concurrently with a raster type video signal comprising:
- means for modulating said data signals;
- means for pseudo randomly selecting video lines on which said data signals are to be modulated;
- and
- means for combining said modulated data signals with said video signal on said pseudo randomly selected video lines of the video raster.
A co-channel communication system for transmitting and receiving a signal comprising a raster type video signal and a data signal comprising:
- means for modulating said data signal;
- means for pseudo randomly selecting video lines on which said data signal is to be modulated;
- means for combining said modulating data signal and said video signal on said pseudo randomly selected video lines;
- means responsive to said combining means and said pseudo randomly selecting means for transmitting said combined signal;
- means for receiving said combining signal;
- and
- means for recovering said data signal from said combined signal.
A co-channel communication system for receiving a data signal concurrently transmitted with a raster type video signal, comprising:
- means for demodulating pseudo randomly selected video lines, said pseudo randomly selected video lines being selected according to a pseudo-random sequence;
- and
- means for recovering said data signal from said pseudo randomly selected video lines.
A method for transmitting one or more data signals with a raster type video signal on one or more predetermined channels in a manner such that the data is imperceptible to a viewer viewing a display of the video signal comprising the steps of:
- (a) modulating the data signal;
- (b) pseudo randomly selecting video lines on which to modulate the data signal;
- and,
- (c) combining said modulated data signal with a raster type video signal on said pseudo randomly selected video lines of a video raster.
Dependencies are inferred from the claim text.