Code converters
CA 1113609 A · Owner: Post Office · Inventors: Everard, John D.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A digital-to-analogue converter which uses a technique of two-level quantisation in order to generate a pulse density modulated signal which yields the analogue signal when filtered. Standard digital logic adders and registers are used in the conversion of PCM signals to the pulse density modulated signal. The adders and registers are arranged as a feedback loop in which an approximation signal capable of either a "high" or a "low" level is compared repetititively with a PCM signal and the difference is accumulated but at the end of each operation the accumulated total is tested and the value of the approximation signal for the next cycle is chosen so as to reduce the accumulated total. The …
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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
- Granted December 1, 1981. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended December 1, 1998.
- 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.