Compatible non-linear pre-emphasis for composite video signals
CA 2099131 A1 · Owner: Nds Limited · Inventors: Beech, Brian Herbert
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
When a video signal including a component modulated onto a subcarrier (such as a PAL signal) is subjected to a non-linear pre-emphasis known for MAC signals, with the object of reducing the effects of noise encountered in transmitting the composite signal through an f.m. channel, problems of noise and differential gain remain. These problems are overcome by subjecting the composite signal to a filtering step before application of the non-linear processing so as, to filter out the subcarrier, the chrominance subcarrier in a PAL signal, and to compand the chrominance sidebands. Preferably a notch filter is used which has a notch shaped as a Gaussian curve.
Read the whole patent
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 20, 1991. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended December 20, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by December 20, 2013.
- 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.