Patents by Inventor Brian L. Abernathy

Brian L. Abernathy 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).

  • Position digitizer circuit for a moveable instrument
    Patent number: 5107079
    Abstract: The invention is a digitizer circuit in a peripheral system for a computer comprising a moveable instrument and a planar grid in which an excitation signal in one of said instrument and grid generates an induced signal in the other one of said instrument and grid, and wherein the phase difference between said excitation and induced signals is indicative of the position of said instrument with respect to said grid, comprising means for summing said excitation and induced signals to produce a sum signal and means for producing an output signal whose frequency is a function of the amplitude of said sum signal.
    Type: Grant
    Filed: March 18, 1991
    Date of Patent: April 21, 1992
    Assignee: Calcomp Inc.
    Inventors: Jason J Hoendervoogt, Brian L. Abernathy