Patents by Inventor Stuart K. Francis

Stuart K. Francis 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).

  • Rotational vibration compensation using a fixed head and a constant frequency pattern
    Patent number: 6304406
    Abstract: An apparatus and method for minimizing the effects of rotational vibration upon a disc drive having a base deck supporting a rotatable disc and an actuator having a moveable data head. A fixed head is supported over the disc at a predetermined radius and transduces a circumferentially extending frequency pattern written to the disc at a constant frequency to generate a readback signal. A frequency modulation (FM) demodulator generates a rotational velocity signal indicative of application of rotational vibration to the base deck in relation to changes in frequency of the readback signal. A servo circuit controllably positions the moveable data head in response to the rotational velocity signal and servo information readback by the moveable data head. The servo circuit interrupts a data transfer operation between the moveable data head and a host device when a magnitude of the rotational velocity signal exceeds a predetermined threshold.
    Type: Grant
    Filed: December 18, 1998
    Date of Patent: October 16, 2001
    Assignee: Seagate Technology LLC
    Inventors: D Brent Douglas, Lealon R. McKenzie, Nathaniel B. Wilson, Stuart K. Francis, Arthur J. Clark
  • Rotational vibration compensation using a dedicated surface with a constant frequency pattern
    Patent number: 6285522
    Abstract: An apparatus and method for minimizing the effects of rotational vibration upon a disc drive having first and second heads supported adjacent first and second disc recording surfaces, respectively. A frequency modulation (FM) demodulator generates a rotational velocity signal indicative of application of rotational vibration to the base deck in relation to changes in frequency of a readback signal generated from a circumferentially extending frequency pattern written to the first disc recording surface at a constant frequency. A servo circuit controllably positions the first and second heads in response to servo information stored on the second disc recording surface and the rotational velocity signal from the FM demodulator. The servo circuit further interrupts a data transfer operation between the second disc recording surface and a host device when a magnitude of the rotational velocity signal exceeds a predetermined threshold.
    Type: Grant
    Filed: December 18, 1998
    Date of Patent: September 4, 2001
    Assignee: Seagate Technology LLC
    Inventors: Lealon R. McKenzie, D. Brent Douglas, Nathaniel B. Wilson, Stuart K. Francis
  • Method and apparatus for controlling a motor in a disc drive by modulating the commutation angle
    Patent number: 6016043
    Abstract: A motor control circuit controls a motor in a disc drive is provided. The motor control circuit includes a commutation circuit which provides commutation signals to the motor to commutate the motor at a commutation frequency. A frequency modulation circuit is operably coupled to the commutation circuit. The frequency modulation circuit provides a modulation signal which frequency modulates the commutation frequency according to a predetermined pattern.
    Type: Grant
    Filed: January 28, 1998
    Date of Patent: January 18, 2000
    Assignee: Seagate Technology, Inc.
    Inventors: Andrew R. Motzko, Garry E. Korbel, John M. Baker, Stuart K. Francis