Patents by Inventor Tadashi Sagawa

Tadashi Sagawa 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: 6115350
    Abstract: An optical disk apparatus adapted to a mark edge recording method having a structure such that a data pattern experimentally recorded on an optical disk with one write power is reproduced plural times while changing reproducing conditions (for example, a slice level for binary-coding a reproduced analog signal) and the number of errors is calculated whenever the reproducing process is performed. The thus-structured process is repeated for using a plurality of write powers. An appropriate write power for the optical disk is determined in accordance with the obtained results of the calculations of the number of errors. In a case of a read-only optical disk, a data pattern experimentally and previously recorded on the optical disk is reproduced plural times by changing the reproducing conditions (for example, a slice level for binary-coding a reproduced analog signal), and the number of errors is calculated whenever the reproducing process is performed.
    Type: Grant
    Filed: February 16, 1999
    Date of Patent: September 5, 2000
    Assignee: Fujitsu Limited
    Inventors: Satoshi Furuta, Toru Fujiwara, Shigenori Yanagi, Tadashi Sagawa, Masaharu Moritsugu
  • Patent number: 5920534
    Abstract: An optical disk apparatus adapted to a mark edge recording method having a structure such that a data pattern experimentally recorded on an optical disk with one write power is reproduced plural times while changing reproducing conditions (for example, a slice level for binary-coding a reproduced analog signal) and the number of errors is calculated whenever the reproducing process is performed. The thus-structured process is repeated for using a plurality of write powers. An appropriate write power for the optical disk is determined in accordance with the obtained results of the calculations of the number of errors. In a case of a read-only optical disk, a data pattern experimentally and previously recorded on the optical disk is reproduced plural times by changing the reproducing conditions (for example, a slice level for binary-coding a reproduced analog signal), and the number of errors is calculated whenever the reproducing process is performed.
    Type: Grant
    Filed: March 19, 1998
    Date of Patent: July 6, 1999
    Assignee: Fujitsu Limited
    Inventors: Satoshi Furuta, Toru Fujiwara, Shigenori Yanagi, Tadashi Sagawa, Masaharu Moritsugu
  • Patent number: 5777964
    Abstract: An optical disk apparatus adapted to a mark edge recording method having a structure such that a data pattern experimentally recorded on an optical disk with one write power is reproduced plural times while changing reproducing conditions (for example, a slice level for binary-coding a reproduced analog signal) and the number of errors is calculated whenever the reproducing process is performed. The thus-structured process is repeated for using a plurality of write powers. An appropriate write power for the optical disk is determined in accordance with the obtained results of the calculations of the number of errors. In a case of a read-only optical disk, a data pattern experimentally and previously recorded on the optical disk is reproduced plural times by changing the reproducing conditions (for example, a slice level for binary-coding a reproduced analog signal), and the number of errors is calculated whenever the reproducing process is performed.
    Type: Grant
    Filed: November 12, 1996
    Date of Patent: July 7, 1998
    Assignee: Fujitsu Limited
    Inventors: Satoshi Furuta, Toru Fujiwara, Shigenori Yanagi, Tadashi Sagawa, Masaharu Moritsugu