Method of and apparatus for modifying a video signal to prevent unauthorized recording and reproduction thereof
CA 1095164 A · Owner: Sony Corporation · Inventors: Morio, Minoru; Kambara, Masahiro
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A method of and apparatus for modifying a video signal such that a video picture can be reproduced by a video display device in response to the modified video signal but if the modi-, fied video signal is transmitted and then recorded on a video signal recorder, a satisfactory video picture cannot be reproduced if that recorded modified video signal subsequently is played back. A pulse whose amplitude is substantially equal to the peak white level of the video signal is inserted into respective horizontal blanking intervals of the video signal. If this modified video signal is recorded on a conventional type of video signal recorder the presence of the inserted pulse signal is detected by …
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Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Granted February 3, 1981. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended February 3, 1998.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
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Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.