Patents by Inventor Kohji Nakao

Kohji Nakao 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: 7852589
    Abstract: Embodiments in accordance with the present invention provide a magnetic disk drive capable of achieving error recovery stably in a simple configuration in the event of thermal asperity (TA) and minimizing the error recovery time required, and a method for controlling the disk drive. According to one embodiment, if TA occurs, a cutoff frequency of a high-pass filter to which a data read signal is input is first increased and a loop gain of a low-order finite impulse response (FIR) filter connected in series to an FIR filter is also increased as high as possible. Next, a Viterbi decoder to which a signal is input from the low-order FIR filter provides feedback to the low-order FIR filter so that an input signal error becomes a minimum. Tap coefficients of the low-order FIR filter are thus optimized.
    Type: Grant
    Filed: April 25, 2007
    Date of Patent: December 14, 2010
    Assignee: Hitachi Global Storage Technologies, Netherlands, B.V.
    Inventors: Masaomi Ikeda, Takao Matsui, Masahiko Koizumi, Masato Taniguchi, Kohji Nakao, Hideaki Maeda
  • Publication number: 20070263310
    Abstract: Embodiments in accordance with the present invention provide a magnetic disk drive capable of achieving error recovery stably in a simple configuration in the event of thermal asperity (TA) and minimizing the error recovery time required, and a method for controlling the disk drive. According to one embodiment, if TA occurs, a cutoff frequency of a high-pass filter to which a data read signal is input is first increased and a loop gain of a low-order finite impulse response (FIR) filter connected in series to an FIR filter is also increased as high as possible. Next, a Viterbi decoder to which a signal is input from the low-order FIR filter provides feedback to the low-order FIR filter so that an input signal error becomes a minimum. Tap coefficients of the low-order FIR filter are thus optimized.
    Type: Application
    Filed: April 25, 2007
    Publication date: November 15, 2007
    Applicant: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Masaomi Ikeda, Takao Matsui, Masahiko Koizumi, Masato Taniguchi, Kohji Nakao, Hideaki Maeda
  • Publication number: 20050052784
    Abstract: A compact hard disk drive that operates silently at a low power consumption needs a suspension assembly that places a low load on the magnetic head. In one embodiment, a suspension assembly comprises a head arm mounted on a carriage shaft, a load beam capable of placing load on a magnetic head and serving as a beam, and a flexure assembly. The flexure assembly includes a flexure formed by processing a thin metal sheet, an insulating layer laminated to the flexure, a wiring pattern formed on the insulating layer, and a protective layer coating the wiring pattern. The flexure has a flexible part for placing load on the magnetic head, a gimbals to which the magnetic head is attached, and a base part attached to the head arm. The elastic part of the flexure generates a very load in the range of about 0.5 to about 1 g.
    Type: Application
    Filed: July 21, 2004
    Publication date: March 10, 2005
    Applicant: Hitachi Global Storage Technologies Netherlands, B.V.
    Inventors: Hiroo Inoue, Taichi Nakamura, Kohji Nakao, Akihiro Sera