Tone and periodical signal detection
CA 2247216 C · Owner: Reesor, Gordon J. · Inventors: Jin, Gary Q.; Reesor, Gordon J.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Algorithms for quickly and efficiently detecting a periodic signal such as a DTMF signal in a telephone system are described. The algorithms, implemented in a tone detector, detect the periodicity of the input data and do not require an estimation of the tone frequency.
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 September 15, 1998 and granted January 15, 2002. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended September 15, 2018.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by September 15, 2020.
- 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.