Automatic frequency control circuit
CA 2012280 C · Owner: Satomi, Hideo · Inventors: Satomi, Hideo
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An AFC circuit for use in a chrominance signal processing circuit of a VTR basically includes a NCO (9) a frequency divider (9, 10, 11, 12, 13) for frequency-dividing an output of the NCO and a phase, comparing circuit (17) for comparing phases of the output, of the divider and a horizontal synchronizing signal extracted from an inputted video signal to supply an error output to the VCO. When a phase relation between the output of the divider and the horizontal synchronizing signal becomes a miss-locked state out of the phase-locked state, a frequency-dividing operation is stopped at a timing corresponding to a rise of a normal inputted signal in a phase-locked state and the …
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 March 15, 1990 and granted August 31, 1999. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended March 15, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by March 15, 2012.
- 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.