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Expired Canadian patentCanada

Digital communication system

CA 1254622 A · Owner: Mitsubishi Denki Kabushiki Kaisha · Inventors: Ariyavisitakul, Sirikiat; Yoshida, Susumu; Takeuchi, Tsutomu

CIPO record

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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 communication system employs a signal whose carrier phase is shifted by a constant amount .DELTA..theta. per time slot in correspondence to each symbol (1 or 0) transmitted the phase shift being performed by .DELTA..theta./2 (or -.DELTA..theta./2) in the first 1/2 time slot and further by .DELTA..theta./2 (or - .DELTA..theta./2) in the second 1/2 time slot thereby to improve the bit error rate in multipath propagation.

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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 May 23, 1989. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended May 23, 2006.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledAugust 23, 1985
GrantedMay 23, 1989
Term endedMay 23, 2006
Patent numberCA 1254622 A
Classification (IPC)H04B7/24 +2 more

Timeline

Timeline From CIPO dates

1986198919921995199820012004Application filedAug 23, 1985Patent grantedMay 23, 1989Term endedMay 23, 2006

Sources & verification

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