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Expired Canadian patentCanada

Channel switching system

CA 1238724 A · Owner: Nec Corporation · Inventors: Morimoto, Hideaki; Hashimoto, Hiromi

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 channel switching system in a digital radio transmission circuit with at least one regular channel and a standby channel has a received signal supply circuit signal frequency divider circuits, signal order change circuits, a comparator, a hitless signal switching circuit and a frequency multiplier. Each channel transmits a digital multiplexed signal including a data signal of N (N is an integer of 1 or more) strings. The received signal supply circuit supplies a data signal to a receiving-side regular channel through a standby channel when a corresponding transmitting-side regular channel has a circuit failure. The signal frequency divider circuits N frequency-divide a data signal …

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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 June 28, 1988. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended June 28, 2005.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledNovember 1, 1985
GrantedJune 28, 1988
Term endedJune 28, 2005
Patent numberCA 1238724 A
Classification (IPC)H04J3/02 +1 more

Timeline

Timeline From CIPO dates

1986198819901992199419961998200020022004Application filedNov 1, 1985Patent grantedJune 28, 1988Term endedJune 28, 2005

Sources & verification

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