Double conversion digital tuning system
CA 2104182 C · Owner: Zenith Electronics Corporation · Inventors: Dobrovolny, Pierre
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A double conversion tuning system for a high definition television receiver includes a microprocessor supplying first and second digital numbers to first and second local oscillators. The first local oscillator is controlled by a wide band phase locked loop that includes a programmable divider that receives the first digital number from the microprocessor and a prescaler that couples the first local oscillator signal to the programmable divider. The output of the programmable divider supplies one input of a phase detector the other input of which, is supplied with the divided down output of a crystal reference source. The output of the phase detector controls the first local oscillator …
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 August 16, 1993 and granted March 30, 1999. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended August 16, 2013.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by August 16, 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.