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Expired Canadian patentCanada

Automatic dynamic equalizing

CA 1279581 C · Owner: Short, William R. · Inventors: Short, William R.; Chellquist, Malcolm

CIPO record

Overview

Drawings and full text

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

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Abstract From the Canadian patent

An automatic dynamic equalizer includes left and right input terminals, an input adder and left and right output adders. The left and right input terminals are connected to inputs of the input adder and inputs of the left and right output adder, respectively. The output of the input adder is connected to the input of a 2:1 compressor. The output of the 2:1 compressor is connected to the input of a bandpass filter having a transmission in the low bass frequency region centered at a frequency of about 60 Hz. The output of the bandpass filter is coupled to inputs of the left and right output adders.

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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 January 29, 1991. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended January 29, 2008.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledDecember 21, 1987
GrantedJanuary 29, 1991
Term endedJanuary 29, 2008
Patent numberCA 1279581 C
Classification (IPC)H03H11/04 +1 more

Timeline

Timeline From CIPO dates

1988199119941997200020032006Application filedDec 21, 1987Patent grantedJan 29, 1991Term endedJan 29, 2008

Sources & verification

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