Method and apparatus for automatic modulation calibration in a radio transmitter
CA 2182710 C · Owner: Christian, Paul · Inventors: Karczewski, Casimir; Christian, Paul
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
In a transmitter (100), circuitry is employed to automatically calibrate errors in a modulated carrier signal. A generator (320) is activated to generate (510) a low frequency square wave for use as data which is used to generate a modulating signal from which the modulated carrier signal is generated. The modulated carrier signal is down-converted to an intermediate frequency (IF) signal having a steady state IF signal level. The instantaneous IF signal level is compared (545) to the steady state IF signal level to determine (550) whether the instantaneous IF signal level differs from the steady state IF signal level by greater than a predetermined amount and, when, the instantaneous IF …
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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 February 17, 1995 and granted May 1, 2001. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended February 17, 2015.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by February 17, 2017.
- 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
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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.