Quadrature modulation circuit
CA 2096664 C · Owner: Ueda, Hideki · Inventors: Ueda, Hideki
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A quadrature modulation circuit of the present invention has a phase shifter whose shifting amount is fixed at 90 degrees a minute amount-phase, shifter whose shifting amount is variable a detector for detecting an RF signalsupplied from the quadrature modulation circuit by a DC voltage signal and a, control circuit for generating a control signal in accordance with the DC voltage signal from the detector. The phase shifting amount of the minute amount-phase shifter is adjusted by the control signal such that the total amount of phase shifting is maintained at 90 degrees.
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 May 20, 1993 and granted May 27, 1997. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended May 20, 2013.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by May 20, 2015.
- 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.