Patents by Inventor Alan C. Tan

Alan C. Tan 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).

  • Detection and measurement of head disc interference using read back signal (without acoustic emission sensor or laser doppler vibrometer)
    Patent number: 6008640
    Abstract: A method and apparatus for detecting and measuring head-disc interference, in a disc drive, for the purpose of taking preventative and corrective measures, to prevent disastrous head crashes and permanent data loss, is disclosed. The method and apparatus detect and measure the frequency modulation (FM) of a read back signal generated by longitudinal head oscillation, as a result of head-disc interference. The longitudinal head oscillation can be ascribed to the non-linear response of the air bearing supporting the head on the disk surface. The response exhibits a vibration frequency in the head in the 100 to 250 kHz range. The more severe the interference contact is, the higher the vibration amplitude which then leads to read signal frequency modulation (FM). A method and apparatus is described to detect the FM modulation and thereby to detect the severity of the head disk interference for proximity recording. A pre-written pattern on the disk can be read back to monitor for FM, and a modulation index, .beta.
    Type: Grant
    Filed: September 30, 1997
    Date of Patent: December 28, 1999
    Assignee: Seagate Technology, Inc.
    Inventors: Alan C. Tan, Myint Ngwe, Joseph C. Liu