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Expired Canadian patentCanada

Digital equalizer apparatus enabling separate phase and amplitude characteristic modification

CA 1284187 C · Owner: Matsumoto, Masaharu · Inventors: Satoh, Katsuaki; Matsumoto, Masaharu; Ishikawa, Seiichi

CIPO record

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Abstract From the Canadian patent

A digital equalizer for audio system applications is based on a FIR (finite impulse response) digital filter whose amplitude and phase/frequency characteristics can be respectively independently established in accordance with input data representing an arbitrary amplitude/frequency characteristic and input phase data from which an arbitrary phase/frequency characteristic for the filter can be derived. In addition to audio frequency response equalization, the apparatus can be provided with a microphone howl suppression function.

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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

  • Granted May 14, 1991. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended May 14, 2008.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledMarch 23, 1988
GrantedMay 14, 1991
Term endedMay 14, 2008
Patent numberCA 1284187 C
Classification (IPC)H03H17/06 +1 more

Timeline

Timeline From CIPO dates

1989199119931995199719992001200320052007Application filedMarch 23, 1988Patent grantedMay 14, 1991Term endedMay 14, 2008

Sources & verification

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