Transconductance variable method and circuit, and variable bandwidth filter and variable gain amplifier using same

Read the whole patent

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.

Why it's free to use

• Filed December 16, 1997 and never granted as a European patent. Had it been granted, its 20-year term would have ended December 16, 2017.
• 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 16, 2023.
• 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.