Active filter circuit
CA 2014968 C · Owner: Hosoya, Nobukazu · Inventors: Hosoya, Nobukazu; Sasaki, Toru; Miura, Katsunori
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An active filter circuit includes a first and second differential pairs each having a pair of transistors. A capacitor is connected to a collector of each on transistor of the first and second differential pairs. A first and second negative feed-back paths are connected, respectively, between the collector and a base of one transistor of the first differential pair and between the collector of one transistor of the second differential pair and a base of the other transistor of the first differential pair. By applying suitable voltages to respective inputs of the differential pairs the active filter circuit functions as a band-pass filter, lowpass filter, high-pass filter band, elimination …
Read the whole patent
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
- Filed April 19, 1990 and granted December 14, 1999. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended April 19, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by April 19, 2012.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.