Patents by Inventor Grant S. Christiansen

Grant S. Christiansen 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).

  • Publication number: 20040208611
    Abstract: A technique that eliminates or minimizes the effects of reflective surfaces to reduce or eliminate interference in the data stream and allow an optical wireless communication link to be used reliably. The most important reflective surface is the reflective surface in front of the data detector itself, as that is the one that will be reflected after the transmitting and receiving stations are properly aligned. The greatest reduction in reflected data associated with a remote detector is then achieved by angling the surface in front of the data detector itself, such that reflections from that surface will not fall within the field of view of the remote detector once the stations are properly aligned.
    Type: Application
    Filed: April 24, 2002
    Publication date: October 21, 2004
    Inventors: Eric G. Oettinger, Mark D. Heminger, Mark D. Hagen, Karl K. Northrup, Robert E. Jansen, James E. Noxon, Grant S. Christiansen
  • Publication number: 20040208529
    Abstract: A method of implementing packet corruption to halt propagation in an optical wireless communication link in a manner that simultaneously minimizes network overhead and maintains a high bandwidth loop sufficient to control the motion of the mirror.
    Type: Application
    Filed: May 14, 2002
    Publication date: October 21, 2004
    Inventors: James E. Noxon, Karl K. Northrup, Grant S. Christiansen
  • Patent number: 6639748
    Abstract: The present invention may be regarded as a disk drive comprising a disk having a plurality of data tracks, each data track comprising a plurality of sectors. A sync mark detector detects a sync mark pattern in a sector, wherein when the sync mark pattern is detected a sync mark detect signal and a polarity signal are generated. The polarity signal represents an expected polarity of pulses in a read signal representing data stored in the sector, wherein the polarity signal enhances the detection of an estimated data sequence from the read signal.
    Type: Grant
    Filed: February 28, 2001
    Date of Patent: October 28, 2003
    Assignee: Western Digital Technologies, Inc.
    Inventors: Grant S. Christiansen, Mark D. Hagen
  • Patent number: 6603622
    Abstract: The present invention may be regarded as a disk drive comprising a disk having a plurality of data tracks, each data track comprising a plurality of sectors. A sync mark detector detects a sync mark pattern in a sector by filtering a read signal with a matched filter having an impulse response substantially matched to a dibit response of the disk drive. The output of the matched filter is correlated with a dual polarity correlator to generate first and second correlated signals. The sync mark pattern is detected when either the first or second correlated signals exceeds a threshold.
    Type: Grant
    Filed: February 28, 2001
    Date of Patent: August 5, 2003
    Assignee: Western Digital Technologies, Inc.
    Inventors: Grant S. Christiansen, Mark D. Hagen
  • Patent number: 6369969
    Abstract: A disk drive is disclosed comprising a bias layer in a magnetoresistive (MR) head actuated over a disk having a plurality of data tracks, each data track comprising a plurality of sectors. A sync mark detector detects a sync mark pattern in a sector, wherein when the sync mark pattern is detected a sync mark detect signal and a polarity signal are generated. The polarity signal indicates when the polarity of the bias layer has deviated from a preferred polarity, wherein the polarity of the bias layer is realigned back toward the preferred polarity.
    Type: Grant
    Filed: February 28, 2001
    Date of Patent: April 9, 2002
    Assignee: Western Digital Technologies, Inc.
    Inventors: Grant S. Christiansen, Mark D. Hagen