Non-sharp cut filters for assembling and splitting in weston clean pal
CA 2078432 A1 · Owner: British Broadcasting Corporation · Inventors: Drewery, John Oliver; Wells, Nicholas Dominis
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An assembler and splitter of a Weston PAL (W-PAL) video signal has filter functions F1, F2 at the assembler for the luminance and chrominance components and corresponding functions F3 F4, at the splitter. The transfer functions are defined as F1 = (L2 + L1)/2 + (L2 - L1) z-1/2, F2 = -(H1 - H2)/2 + (H1 + H2) z-1/2, F3 = (L2 - L1)/2 + (L2 + L1) z-1/2, F4 = (H1 + H2)/2 - (H1 - H2) z-1/2 and wherein H1 (f) = L2 (2fsc - f) and H2 (f) = L1 (2fsc - f). Thus the filters are non-sharp cut and are compatible with normal PAL.
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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 January 24, 1992. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended January 24, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by January 24, 2014.
- 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.