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Expired Canadian patentCanada

Method and device for eliminating the effect of periodic disturbance variables having a known, variable frequency

CA 2020661 C · Owner: Siemens Aktiengesellschaft · Inventors: Weihrich, Georg; Wohld, Dietrich; Jungkunz, Clemens

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Abstract From the Canadian patent

A signal which is dependent solely on the disturbance variable is selected by means of a filter and fed to a disturbance detector. This disturbance detector simulates the steady and alternating component (sine component) of the selected signal as well as a, signal (cosine component) phase-leading by 90° with the latter signal. The correction signal required to exactly compensate for the disturbance variable is determined from the sine and cosine component of the periodic disturbance signal component by means of frequency-controlled function generators and a complex phasor calculation.

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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 July 6, 1990 and granted October 17, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended July 6, 2010.
  • A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by July 6, 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.
FiledJuly 6, 1990
GrantedOctober 17, 2000
Term endedJuly 6, 2010
Patent numberCA 2020661 C
Classification (IPC)H04B15/00 +2 more

Timeline

Timeline From CIPO dates

1991199319951997199920012003200520072009Application filedJuly 6, 1990Patent grantedOct 17, 2000Term endedJuly 6, 2010

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Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.