Process and device for transmitting video signals in a confined spaces
CA 2069748 A1 · Owner: Charbonnages De France · Inventors: Degardin, Daniel; Baudet, Jacques; Charpentier, Dominique
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A UHF carrier signal modulated by a video signal where the frequency and the format of a line synchronisation signal are known, is transmitted in a transmission region in a confined medium by a microwave link. In a reception region, two signals are received along two angularly offset privileged axes, each is frequency-demodulated along identical processing channels, the existence in the signal emitted from one of the channels, the "starting channel" of, a periodic signal with the line synchronisation frequency is checked and this signal is selected if the check proves positive. If the periodic signal disappears the test is, applied to the other channel; if that check is positive this other …
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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
- Filed December 7, 1990. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended December 7, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by December 7, 2012.
- 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
Timeline From CIPO dates
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.