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Expired Canadian patentCanada

Tuning system equalized with the slope factor of the tuning curve

CA 1111581 A · Owner: Zenith Radio Corporation · Inventors: Tanaka, Akio

CIPO record

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Abstract From the Canadian patent

A tuning system for a television receiver includes a channel number generator coupled to nominal tuning memories fine, tune memories and slope factor memories. The memory outputs are coupled to a corresponding plurality of comparators which are also coupled to counters for deriving pulse-width modulated (PWM) signals corresponding to tuning information stored in the memories. The PWM signals are supplied to a tuning voltage generator where they are combined to produce the tuning voltage for the tuner. The information in the slope factor memories is based upon the slope of the tuning curve corresponding to the selected channel number. The final tuning voltage consists of the nominal tuning …

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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

  • Granted October 27, 1981. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended October 27, 1998.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledApril 7, 1978
GrantedOctober 27, 1981
Term endedOctober 27, 1998
Patent numberCA 1111581 A
Classification (IPC)H04B1/26 +2 more

Timeline

Timeline From CIPO dates

1979198119831985198719891991199319951997Application filedApril 7, 1978Patent grantedOct 27, 1981Term endedOct 27, 1998

Sources & verification

Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.