Patents by Inventor Keith R. Griffith

Keith R. Griffith 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).

  • Patent number: 10613559
    Abstract: A method described herein includes describing a load current with a discrete time function. The method includes using a first frequency and a second frequency to provide an approximation of the described load current, wherein a transform applied to the discrete time function identifies the first frequency and the second frequency. The method includes estimating a loop inductance and a loop resistance of a wire loop by exciting a transmit circuit with a voltage reference step waveform, wherein the transmit circuit includes the wire loop. The method includes scaling the approximated load current to a level sufficient to generate a minimum receive voltage signal in a receiver at a first distance between the wire loop and the receiver. The method includes generating a first voltage signal using the scaled load current, estimated loop inductance, and estimated loop resistance. The method includes exciting the transmit circuit with the first voltage signal.
    Type: Grant
    Filed: March 7, 2019
    Date of Patent: April 7, 2020
    Assignee: RADIO SYSTEMS CORPORATION
    Inventors: Scott A McFarland, Keith R. Griffith
  • Publication number: 20190204860
    Abstract: A method described herein includes describing a load current with a discrete time function. The method includes using a first frequency and a second frequency to provide an approximation of the described load current, wherein a transform applied to the discrete time function identifies the first frequency and the second frequency. The method includes estimating a loop inductance and a loop resistance of a wire loop by exciting a transmit circuit with a voltage reference step waveform, wherein the transmit circuit includes the wire loop. The method includes scaling the approximated load current to a level sufficient to generate a minimum receive voltage signal in a receiver at a first distance between the wire loop and the receiver. The method includes generating a first voltage signal using the scaled load current, estimated loop inductance, and estimated loop resistance. The method includes exciting the transmit circuit with the first voltage signal.
    Type: Application
    Filed: March 7, 2019
    Publication date: July 4, 2019
    Inventors: Scott A. McFarland, Keith R. Griffith
  • Patent number: 10268220
    Abstract: A method described herein includes describing a load current with a discrete time function. The method includes using a first frequency and a second frequency to provide an approximation of the described load current, wherein a transform applied to the discrete time function identifies the first frequency and the second frequency. The method includes estimating a loop inductance and a loop resistance of a wire loop by exciting a transmit circuit with a voltage reference step waveform, wherein the transmit circuit includes the wire loop. The method includes scaling the approximated load current to a level sufficient to generate a minimum receive voltage signal in a receiver at a first distance between the wire loop and the receiver. The method includes generating a first voltage signal using the scaled load current, estimated loop inductance, and estimated loop resistance. The method includes exciting the transmit circuit with the first voltage signal.
    Type: Grant
    Filed: July 14, 2016
    Date of Patent: April 23, 2019
    Assignee: Radio Systems Corporation
    Inventors: Scott A McFarland, Keith R Griffith
  • Publication number: 20180017981
    Abstract: A method described herein includes describing a load current with a discrete time function. The method includes using a first frequency and a second frequency to provide an approximation of the described load current, wherein a transform applied to the discrete time function identifies the first frequency and the second frequency. The method includes estimating a loop inductance and a loop resistance of a wire loop by exciting a transmit circuit with a voltage reference step waveform, wherein the transmit circuit includes the wire loop. The method includes scaling the approximated load current to a level sufficient to generate a minimum receive voltage signal in a receiver at a first distance between the wire loop and the receiver. The method includes generating a first voltage signal using the scaled load current, estimated loop inductance, and estimated loop resistance. The method includes exciting the transmit circuit with the first voltage signal.
    Type: Application
    Filed: July 14, 2016
    Publication date: January 18, 2018
    Inventors: Scott A. McFarland, Keith R. Griffith