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Expired European patentEurope

Precision control frequency synthesizer having an unstable, variable frequency input signal

EP 0173699 B1 · Applicant: AT&T Corp.

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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 January 29, 1985 and granted November 29, 1989. A European patent lasts at most 20 years from filing, so its term ended January 29, 2005.
  • 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 July 29, 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.
FiledJanuary 29, 1985
PublishedMarch 12, 1986
GrantedNovember 29, 1989
Term endedJanuary 29, 2005
Application numberEP 85900928
Classification (CPC)H03L7/16 +1 more

Timeline

Timeline From EPO dates

1986198819901992199419961998200020022004Application filedJan 29, 1985PublishedMarch 12, 1986Patent grantedNov 29, 1989Term endedJan 29, 2005

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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