Two-frequency transmitting apparatus with tone-modulation phasing for an instrument landing system
CA 2089524 C · Owner: Alcatel Sel Aktiengesellschaft · Inventors: Poschadel, Werner; Greving, Gerhard
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Two-frequency transmitting apparatus (S1 S2, LA) for, instrument-landing systems is disclosed which is insensitive to so-called DDM distortions caused by reflections of the clearance signal from obstacles (H) located near the runway (RW). This insensitivity is achieved by different phase shifts of the equal modulation frequency (90 Hz and 150 Hz) used for the course and clearance signals. The different phase shifts correspond to a phase shift of a common fundamental frequency (30 Hz). The two-frequency transmitting apparatus can be used to specify a localizer course or a glide path.
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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 15, 1993 and granted September 9, 2003. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended February 15, 2013.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by February 15, 2015.
- 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.