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Expired Canadian patentCanada

Compatible am broadcast/data transmission system

CA 1237782 A · Owner: Kahn, Leonard R. · Inventors: Kahn, Leonard R.

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 system for transmitting a composite signal comprising a data transmission signal component and an AM broadcast signal component. The broadcast signal component may be monophonic or stereophonic. The level of the data signal component is made a function of the modulation level so that the data signal is masked by the program modulation and, therefore, AM radio listeners will not be disturbed by the data signal. The rate of data transmission is reduced as the level of the data signal is reduced. The data signal is in quadrature with the AM carrier so as to minimize detection of the data signal by an envelope demodulator. Suitable data receivers are also disclosed.

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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 7, 1988. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended June 7, 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.
FiledMay 24, 1985
GrantedJune 7, 1988
Term endedJune 7, 2005
Patent numberCA 1237782 A
Classification (IPC)H04B1/04

Timeline

Timeline From CIPO dates

1986198819901992199419961998200020022004Application filedMay 24, 1985Patent grantedJune 7, 1988Term endedJune 7, 2005

Sources & verification

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