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Expired Canadian patentCanada

Frequency equalizer

CA 2020258 C · Owner: Eguchi, Takeo · Inventors: Eguchi, Takeo

CIPO record

Overview

Drawings and full text

Its claims, description and drawings are in the Canadian Patents Database.

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Abstract From the Canadian patent

A frequency equalizer is provided for suitably correcting a frequency characteristic of a signal transmitted through a signal transmitting system such as a coaxial cable and the like. The frequency equalizer has a plurality of serially connected fundamental circuits in each of which an input signal is processed by a series circuit of a multiplying circuit and an amplifier having its own frequency characteristic to generate a first signal, the input signal is processed by an amplifier having a flat frequency characteristic to generate a second signal and the first and second signals are added or subtracted to derive an output signal. Therefore, a desired frequency characteristic can be …

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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 29, 1990 and granted September 4, 2001. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended June 29, 2010.
  • A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by June 29, 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.
FiledJune 29, 1990
GrantedSeptember 4, 2001
Term endedJune 29, 2010
Patent numberCA 2020258 C
Classification (IPC)H04B3/14 +1 more

Timeline

Timeline From CIPO dates

1991199319951997199920012003200520072009Application filedJune 29, 1990Patent grantedSep 4, 2001Term endedJune 29, 2010

Sources & verification

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