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Expired European patentEurope

Equalization circuits for magnetic recording channels

EP 0147550 B1 · Applicant: International Business Machines Corporation

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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 October 16, 1984 and granted June 22, 1988. A European patent lasts at most 20 years from filing, so its term ended October 16, 2004.
  • 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 April 16, 2010.
  • 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.
FiledOctober 16, 1984
PublishedJuly 10, 1985
GrantedJune 22, 1988
Term endedOctober 16, 2004
Application numberEP 84112379
Classification (CPC)G11B20/10009 +2 more

Timeline

Timeline From EPO dates

1985198719891991199319951997199920012003Application filedOct 16, 1984PublishedJuly 10, 1985Patent grantedJune 22, 1988Term endedOct 16, 2004

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

Everything on this page comes from the EPO record linked above. EPO data used under CC BY 4.0.