Video telephone employing pulse width modulation for data transmission
CA 2063258 A1 · Owner: Perelman, Frank M. · Inventors: Perelman, Frank M.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A video telephone employing pulse width modulation (10) is implemented. Minimal components are employed and the entire circuit is comprised of digital components except for a few analog components including a comparator (98) for detecting transitions in a received pulse width modulation signal. The pulse width magnitude for each transmitted data is determined by the binary value of the data input (81). The video picture along with the synchronization signals from a video source (12) are digitized and stored in a memory (24). The video telephone (10) operates by sending and receiving via pulse width modulation both the video data and the synchronization signals. The inverse of the video is …
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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 June 19, 1990. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended June 19, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by June 19, 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.