Radiotelephone system
CA 2021847 C · Owner: Nishi, Kazuhiko · Inventors: Nishi, Kazuhiko; Kawaguchi, Youichi; Kikuchi, Hajime
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A radiotelephone system having a base unit and a plurality of subordinate units for carrying out radiocommunication between them. The base unit has one or more sending sections and one or more receiving sections and each of the subordinate units has a sending part and a receiving part. The system includes a first frequency varying part for shifting periodically sending carrier frequencies of the sending section as well as receiving carrier frequencies of the receiving section to make one sending or receiving carrier frequency at a phase different from that at another preceding phase, a first synchronizing signal part for generating a synchronizing signal in step with a time period …
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 July 24, 1990 and granted January 4, 1994. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended July 24, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by July 24, 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.