Patents by Inventor John P. Zirbel

John P. Zirbel 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).

  • Real-time audio spectrum analyzer
    Patent number: 4275460
    Abstract: A propeller modulation enhancement and display system which suppresses hull cho and displays propeller modulation of a return sonar signal in real time. The real-time operation is obtained through the use of a multichannel frequency spectrum analyzer having a plurality of narrow bandpass filters covering the frequency of interest. Suppression of the hull echo is obtained through the use of a narrow band-reject filter having a variable center frequency. The filter precedes the multichannel frequency spectrum analyzer.
    Type: Grant
    Filed: September 26, 1966
    Date of Patent: June 23, 1981
    Assignee: The United States of America as represented by the Secretary of the Navy
    Inventor: John P. Zirbel