Video tape recorder with audio carrier absence detection
CA 2032290 C · Owner: Miyake, Yoshitaka · Inventors: Miyake, Yoshitaka
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A video tape recorder for recording and/or reproducing a stereo frequency-modulated audio signal by a pair of carrier signals of an indispensable first carrier signal and an additional second carrier signal is comprised of a circuit for demodulating the second carrier signal to provide a demodulated output, and a comparator for comparing an amplitude of the demodulated output with a predetermined value wherein when the, amplitude of the demodulated output is below the predetermined value, it is determined that the second carrier signal exists.
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 December 14, 1990 and granted August 1, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended December 14, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by December 14, 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.