Patents by Inventor Tadahiko Kameyama

Tadahiko Kameyama 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: 6473255
    Abstract: Sense current is applied in pulses, synchronized with the timing clock generated by a clock generator 5, to transducer 2 in the information storage device, reducing the time-averaged value of the sense current. The recorded information on the magnetic disk medium 1 is reproduced by the MR head as reproducing signal pulses in synchronism with the above timing clock. The amplitude of the reproducing signal pulses are proportional to the magnetic field of the magnetic disk medium 1. The reproducing signal pulses are sample-held by a sample-hold circuit 6, and after being digitized by an A/D converter 7, recorded data are retrieved through a demodulator circuit 8 of a partial-response system.
    Type: Grant
    Filed: February 18, 1998
    Date of Patent: October 29, 2002
    Assignee: Hitachi, Ltd.
    Inventors: Noriaki Hatanaka, Tadahiko Kameyama, Takeshi Maeda
  • Publication number: 20010015867
    Abstract: Sense current is applied in pulses, synchronized with the timing clock generated by a clock generator 5, to transducer 2 in the information storage device, reducing the time-averaged value of the sense current. The recorded information on the magnetic disk medium 1 is reproduced by the MR head as reproducing signal pulses in synchronism with the above timing clock. The amplitude of the reproducing signal pulses are proportional to the magnetic field of the magnetic disk medium 1. The reproducing signal pulses are sample-held by a sample-hold circuit 6, and after being digitized by an A/D converter 7, recorded data are retrieved through a demodulator circuit 8 of a partial-response system.
    Type: Application
    Filed: February 18, 1998
    Publication date: August 23, 2001
    Inventors: NORIAKI HATANAKA, TADAHIKO KAMEYAMA, TAKESHI MAEDA
  • Patent number: 5175545
    Abstract: A digital code conversion system in a magnetic recording apparatus for converting one bit of an input digital signal into a signal of two bits, in which the number of binary digits of "0" making appearance between adjacent binary digits of "1" is two at minimum and seven at maximum. In the digital code resulting from the code conversion, ratio between maximum and minimum values of the density at which the binary digit of "1" makes appearance is 1:2.
    Type: Grant
    Filed: January 17, 1989
    Date of Patent: December 29, 1992
    Assignee: Hitachi, Ltd.
    Inventors: Takamasa Uchiyama, Tadahiko Kameyama
  • Patent number: 4914438
    Abstract: In a digital information coding system for transforming a binary digital information train without limitation of bit arrangement into run length limited binary codes, the run length taking only a value obtained by adding an integer multiple of a specific positive integer s to a minimum value d, within the range of the minimum value d and the maximum value k, and the positive integer s is 2 or more and is an aliquant number relative to d+1, and the maximum value k is a value obtained by adding an integer multiple of the positive integer s to the minimum value d.
    Type: Grant
    Filed: July 29, 1988
    Date of Patent: April 3, 1990
    Assignee: Hitachi, Ltd.
    Inventor: Tadahiko Kameyama