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Expired Canadian patentCanada

Amplifier circuit having second order signal cancellation

CA 2033305 C · Owner: Isota, Yoji · Inventors: Urasaki, Shuji; Takagi, Tadashi; Toyoshima, Gen

CIPO record

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Abstract From the Canadian patent

An amplifier circuit suitable for use in various types of communication devices, radar systems and the like, wherein a fundamental-wave signal extracted from an input side is converted into a second order signal and the second order signal is shifted so as to be opposite in phase and equal in amplitude to a second order signal produced by an amplifier such as an FET or multistage operational amplifier. The phase shifted signal is applied to the amplifier output whereby the, second order signal produced by the amplifier can assuredly be equivalently short-circuited and the operation efficiency of the amplifier can be improved.

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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 December 27, 1990 and granted November 9, 1993. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended December 27, 2010.
  • A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by December 27, 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.
FiledDecember 27, 1990
GrantedNovember 9, 1993
Term endedDecember 27, 2010
Patent numberCA 2033305 C
Classification (IPC)H03F1/32

Timeline

Timeline From CIPO dates

1991199319951997199920012003200520072009Application filedDec 27, 1990Patent grantedNov 9, 1993Term endedDec 27, 2010

Sources & verification

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