Patents by Inventor Fumio Iwatani

Fumio Iwatani 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).

  • Carrier relay system
    Patent number: 4620257
    Abstract: In a carrier relay system in which protective relay apparatus are disposed in terminal stations respectively and interchange information between the terminal stations via a signal transmission line for detecting a trouble occurred in power transmission lines on the basis of the exchanged information, specific information K is inserted in a predetermined position of a signal transmitted from the first terminal station to the second terminal station, and the specific information K is inserted intact in another predetermined position of a signal returned from the terminal station to the terminal station. In the terminal station, the specific information K inserted in the signal transmitted therefrom is compared with the specific information K inserted in the signal returned from the terminal station for deciding the presence or absence of a trouble occurred in the power transmission lines.
    Type: Grant
    Filed: July 20, 1984
    Date of Patent: October 28, 1986
    Assignee: Hitachi, Ltd.
    Inventors: Yoshihiro Sano, Fumio Iwatani, Takao Kubo, Yoshiteru Miki