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Expired Canadian patentCanada

Self checking dynamic memory system

CA 1107862 A · Owner: Western Electric Company, Incorporated · Inventors: Fleming, Thomas W.; Cenker, Ronald P.; Huff, Frank R.

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

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Abstract From the Canadian patent

Abstract of the Disclosure The storage space of the instant system is considered, for refresh purposes, to contain 512 groups of 26 bit digital words with each group containing 128 such words. Memory refresh is implemented by sequentially refreshing the groups of digital words at the rate of one group every 2.8 microseconds giving an ex-, pected total memory refresh time of approximately 1.43 milliseconds. A particular digital word from each group of digital words refreshed is read from the memory and transmitted to a parity check circuit which generates fault signals for any digital word having faulty parity. At the end of each of the approximately 1.43 millisecond refresh cycles, the …

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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 August 25, 1981. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended August 25, 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.
FiledMay 10, 1979
GrantedAugust 25, 1981
Term endedAugust 25, 1998
Patent numberCA 1107862 A
Classification (IPC)G11C29/00 +2 more

Timeline

Timeline From CIPO dates

1980198219841986198819901992199419961998Application filedMay 10, 1979Patent grantedAug 25, 1981Term endedAug 25, 1998

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