Patents by Inventor Donald Reid Bush

Donald Reid Bush 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).

  • Spread spectrum clock generator and associated method
    Patent number: 5872807
    Abstract: A clock circuit includes an oscillator for generating a reference frequency signal, and a spread spectrum clock generator cooperating with the oscillator for generating a spread spectrum clock output signal having a fundamental frequency and reduced amplitude EMI spectral components at harmonics of the fundamental frequency. The spread spectrum clock generator preferably includes a clock pulse generator for generating a series of clock pulses, and a spread spectrum modulator for frequency modulating the clock pulse generator to broaden and flatten amplitudes of EMI spectral components which would otherwise be produced by the clock pulse generator. The spread spectrum modulator frequency modulates the clock pulses with specific profiles of frequency deviation versus the period of the profile. Electronic devices including the spread spectrum clock circuit and associated method are also disclosed.
    Type: Grant
    Filed: February 13, 1997
    Date of Patent: February 16, 1999
    Assignee: Lexmark International, Inc.
    Inventors: James Ronald Booth, Donald Reid Bush, John Thomas Fessler, Keith Bryan Hardin
  • Spread spectrum clock generator and associated method
    Patent number: 5867524
    Abstract: A clock circuit includes an oscillator for generating a reference frequency signal, and a spread spectrum clock generator cooperating with the oscillator for generating a spread spectrum clock output signal having a fundamental frequency and reduced amplitude EMI spectral components at harmonics of the fundamental frequency. The spread spectrum clock generator preferably includes a clock pulse generator for generating a series of clock pulses, and a spread spectrum modulator for frequency modulating the clock pulse generator to broaden and flatten amplitudes of EMI spectral components which would otherwise be produced by the clock pulse generator. The spread spectrum modulator frequency modulates the clock pulses with specific profiles of frequency deviation versus the period of the profile. Electronic devices including the spread spectrum clock circuit and associated method are also disclosed.
    Type: Grant
    Filed: February 13, 1997
    Date of Patent: February 2, 1999
    Assignee: Lexmark International Inc.
    Inventors: James Ronald Booth, Donald Reid Bush, John Thomas Fessler, Keith Bryan Hardin