Method and apparatus for reading and writing a multilevel signal from an optical disc
CA 2356858 A1 · Owner: Wong, Terrence L. · Inventors: Powelson, Judith C.; Mclaughlin, Steve W.; Warland, David K.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A system and method are disclosed for reading a multilevel signal from an optical disk (200). The method includes reading a raw analog data signal from a disk (200) using an optical head (204) and adjusting the amplitude of the raw analog data signal. A timing signal is recovered from the amplitude adjusted analog data signal by a signal processor (214). Correction is made for amplitude modulation of the raw analog data signal by processing the raw analog data signal and the timing signal.
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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 February 8, 2000. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended February 8, 2020.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by February 8, 2022.
- 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.