Transmission system for coded speech signals and/or voiceband data
CA 2121896 C · Owner: Davis, Andrew Gordon · Inventors: Davis, Andrew Gordon
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A digital coder receives (input 100) either speech or voice-band data. When receiving speech this is coded by a digital speech coder (102) formatted into frames with parity bits (106). If modulated data are present this is recognized by a detector (107) which routes the signals instead via a demodulator (108). Parity bits are generated from the same frame portions but parity is inverted (110) so that a parity checking unit at a receiver (not shown) can readily recognize the change. Preferably means (111) are provided to insert into data frames codewords identifying the start and end and indicating the type of modulation in use. Additional detectors (107) and demodulators can be added for …
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 November 13, 1992 and granted June 30, 1998. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended November 13, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by November 13, 2014.
- 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.