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Expired European patentEurope

Acoustic characteristic correction circuit in high fidelity amplifier

EP 0390971 B1 · Applicant: Ohkuma, Saburoh

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Overview

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Listed from its EPO record in Patent Yard's archive of European patents past their term. Its claims, description and drawings are in the EPO PDF and on Google Patents, and the Claude kit works from them.

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Why it's free to use

  • Filed December 12, 1989 and granted March 13, 1996. A European patent lasts at most 20 years from filing, so its term ended December 12, 2009.
  • A supplementary protection certificate, which can extend a medicine or crop-protection patent, adds at most five and a half years, so even that would have ended by June 12, 2015.
  • We check European rights only. A US or other national patent in its family could still be in force: check its family on Espacenet or Google Patents.
FiledDecember 12, 1989
PublishedOctober 10, 1990
GrantedMarch 13, 1996
Term endedDecember 12, 2009
Application numberEP 89122911
Classification (CPC)H03G5/165

Timeline

Timeline From EPO dates

1990199219941996199820002002200420062008Application filedDec 12, 1989PublishedOct 10, 1990Patent grantedMarch 13, 1996Term endedDec 12, 2009

Sources & verification

Official EPO records

Full published documentClaims, description and drawings as a PDF.EPOEuropean Patent RegisterProcedure, status, file inspection and legal events.EPOLinked open EP data recordThe bibliographic record this page is built from.EPO

Cross-check elsewhere

Google PatentsFull text, worldwide family, citing patents and legal events.patents.google.comEspacenetNational family members and their legal status.European Patent Office

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