Patents by Inventor Nakahiko Yamaguchi

Nakahiko Yamaguchi 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: 4233668
    Abstract: Method and apparatus for testing a magnetic bubble memory are disclosed wherein a most severe magnetic bubble domain arrangement which fully causes the ununiformity of magnetic interaction between magnetic bubble domains is experimentally determined, and a basic pattern [P] and a test information pattern determining an arrangement of the basic patterns [P] and complementary patterns [P] thereof for realizing that magnetic bubble domain arrangement are stored in memory units, respectively, and the basic patterns [P] and the complementary patterns [P] are sequentially read out in accordance with the test information pattern to generate magnetic bubble domain trains in a storage area of the magnetic bubble memory.
    Type: Grant
    Filed: September 29, 1978
    Date of Patent: November 11, 1980
    Assignees: Nippon Telegraph and Telephone Public Corporation, Hitachi, Ltd.
    Inventors: Nakahiko Yamaguchi, Susumu Hibi, Shigeru Yoshizawa, Shoji Yoshimoto, Akira Kobayashi
  • Patent number: 4145750
    Abstract: A field access magnetic bubble memory device including a memory chip applied with an in-plane magnetic field at need is disclosed. At a transient stop operation of the device before its interrupted state, an in-plane field is removed after it has been held for a predetermined period following the cessation of rotation thereof. The in-plane field may be increased upon the cessation of rotation thereof. At a transient start operation of the device after the interrupted state, an in-plane field having no rotation and the same direction as at the transient stop operation is applied for a predetermined period before the initiation of rotation thereof. The applied in-plane field may be increased upon the initiation of rotation thereof.
    Type: Grant
    Filed: July 19, 1977
    Date of Patent: March 20, 1979
    Assignees: Hitachi, Ltd., Nippon Telegraph and Telephone Public Corporation
    Inventors: Shigeru Yoshizawa, Yutaka Sugita, Nobuo Saito, Yuji Arai, Nakahiko Yamaguchi