Apparatus and method for providing digital audio in the fm broadcast band
CA 2003763 C · Owner: Robbins, Clyde · Inventors: Robbins, Clyde
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Method and apparatus are provided for transmitting, receiving, and reproducing digital audio signals as discrete carriers similar to standard FM broadcast signals. An audio signal is digitized using, for example, adaptive delta modulation techniques. Several channels of audio information, such as left and right stereo channels and a second audio program ( "SAP" ) channel can all be digitized and incorporated onto the digital broadcast signal carrier. The digitized audio signal may be modulated using multiphase modulation of the carrier of an FM broadcast band signal. A plurality of audio channels may be digitized and transmitted over the airwaves, or over a cable transmission network. …
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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 November 23, 1989 and granted October 5, 1993. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended November 23, 2009.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by November 23, 2011.
- 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.