Pulsed-signal magnetomechanical electronic article surveillance system with improved damping of transmitting antenna
CA 2234067 C · Owner: Herring, Richard L. · Inventors: Herring, Richard L.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
In a pulsed-signal magnetomechanical electronic article surveillance system a , single transmit circuit (16) is used to drive two or more parallel-connected interrogation signal transmitting antennas (18-1 18-2). One or more , switchable damping circuits (34-1 34-2) are provided in series with the antennas to promote rapid damping of the interrogation signal at the end of each signal pulse. The damping circuit(s) are situated to provide damping in the loop(s) formed by the parallel connected antennas. Each switchable damping circuit is formed of a resistance (38) connected between a respective antenna and a terminal (36-1, 36-2) of the transmit circuit as well as a switching , element …
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 January 15, 1997 and granted July 8, 2003. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended January 15, 2017.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by January 15, 2019.
- 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.