Spread spectrum digital data transmission over TV video

• US 5,243,423 A
• Filed: 12/20/1991
• Issued: 09/07/1993
• Est. Priority Date: 12/20/1991
• Status: Expired due to Fees

• Current Assignee: Nielsen Media Research, Inc. (Nielsen Holdings plc)
• Original Assignee: A. C. Nielsen Company, LLC (MOOD Media Corporation)
• Inventors: DeJean, Jean P., Weissman, Robert, Lu, Daozheng
• Primary Examiner(s): Groody, James J.
• Assistant Examiner(s): Harvey, David E.
• Application Number:
  US07/811,805
• Time in Patent Office: 627 Days
• Field of Search: 358/142, 358/141, 358/167, 375/1
• US Class Current: 348/473
• CPC Class Codes: H04N 2005/9135 by superimposing the spectrally spread copy protection signal onto the video signal
• CPC Class Codes: H04N 5/913 for scrambling ; for copy protection
• CPC Class Codes: H04N 7/08 Systems for the simultaneous or sequential transmission of more than one television signal, e.g. additional information signals, the signals occupying wholly or partially the same frequency band , e.g. by time division H04N7/007 takes precedence

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.

Claims

1. 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.

2. A co-channel communication system as recited in claim 1, wherein said modulating means includes means for converting said data signal to a spread spectrum signal.

3. A co-channel communication system as recited in claim 1, wherein said modulating means includes means for modulating said data signal according to a pseudo-random sequence.

4. A co-channel communication system as recited in claim 1, wherein said pseudo random selecting means includes means for selecting said video lines according to a pseudo-random sequence.

5. A co-channel communication system as recited in claim 1, wherein said pseudo randomly selected video lines are in an active portion of the video raster.

6. 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.

7. A co-channel communication system as recited in claim 6, wherein said modulating means includes means for modulating said data signal according to a pseudo-random sequence.

8. A co-channel communication system as recited in claim 7, wherein said randomly selected video lines are in an active area of the video raster.

9. A co-channel communication system as recited in claim 6, wherein said modulating means includes means for converting said data signal to a spread spectrum signal.

10. A co-channel communication system as recited in claim 6, further including means for retransmitting said modulated data signal.

11. A co-channel communication system as recited in claim 6, wherein said recovering means includes means for storing the digital data after a predetermined portion of said retransmitted modulated data signal has been recovered.

12. 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.

13. A co-channel communication system as recited in claim 12, wherein said demodulating means includes means for demodulating said data signal according to a pseudo-random sequence.

14. A co-channel communication system as recited in claim 12, wherein said pseudo randomly selected video lines are in an active portion of the video raster.

15. A co-channel communication system as recited in claim 12, wherein said demodulating means includes means for demodulating a spread spectrum signal.

16. 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.

17. A method as recited in claim 16, wherein step (a) includes the step of converting said data signal to a spread spectrum signal.