Audio signal identification using code labels inserted in the audio signal
CA 2248314 C · Owner: Central Research Laboratories Limited · Inventors: Todd, Martin Peter; Johnson, Nigel
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
In an arrangement for decoding code labels embedded in audio signals by inserting signal bursts at selected frequencies into notch frequencies in the audio signal, problems of speed variations in the device producing the audio signal creating notch frequency variation are overcome by providing a plurality of decoders in parallel receiving an incoming signal each decoder , having notch frequencies incrementally displaced from those of the other decoders.
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 14, 1997 and granted May 20, 2003. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended January 14, 2017.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by January 14, 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.