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Expired Canadian patentCanada

D.c.-coupled video clamping circuit

CA 1265609 C · Owner: Lin, Wen Tsung · Inventors: Lin, Wen Tsung

CIPO record

Overview

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Its claims, description and drawings are in the Canadian Patents Database.

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Abstract From the Canadian patent

A d.c.-coupled video clamping circuit is disclosed for operation with normal video signals and sync suppressed scrambled video signals. For receiving normal video signals a, feedback path detects variations in sync tip level from a reference level and applies a corresponding control voltage to a d.c. signal amplifier, thereby to clamp and maintain the sync tip at a fixed (black) level. For receiving sync suppressed scrambled video signals, the feedback path is disabled and a fixed reference voltage is applied to the d.c. signal amplifier.

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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 February 6, 1990. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended February 6, 2007.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledOctober 16, 1987
GrantedFebruary 6, 1990
Term endedFebruary 6, 2007
Patent numberCA 1265609 C
Classification (IPC)H04N5/16 +2 more

Timeline

Timeline From CIPO dates

1988199019921994199619982000200220042006Application filedOct 16, 1987Patent grantedFeb 6, 1990Term endedFeb 6, 2007

Sources & verification

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