Patents by Inventor Duane P. Cooper

Duane P. Cooper has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Multichannel matrix logic and encoding systems
    Patent number: 4152542
    Abstract: Apparatus and methods relating to "quadrasonic" encoding and decoding systems, including synthetic supplementary channel systems, matrix logic systems, and systems employing stereo compatible matrix variations.
    Type: Grant
    Filed: September 26, 1977
    Date of Patent: May 1, 1979
    Inventor: Duane P. Cooper