Patents by Inventor Masayuki Mizoguchi

Masayuki Mizoguchi 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).

  • Subscriber line testing system
    Patent number: 4447679
    Abstract: A testing system connects a subscriber line to be tested by way of a semiconductor switch of a type driven by a constant current to a test equipment to test a subscriber line and a terminal equipment. The test system includes a compensation circuit having means for measuring a constant current component contained in a current flowing through the semiconductor switch into a test line, and means for drawing a constant current component to drive the switch through the test line on the basis of the measuring result to supply the current component obtained by subtracting the constant current component from the current flowing through the test line to the testing equipment.
    Type: Grant
    Filed: March 22, 1982
    Date of Patent: May 8, 1984
    Assignees: Hitachi, Ltd., Nippon Telegraph & Telephone Public Corporation
    Inventors: Takafumi Kojima, Shigeru Yoshida, Masayuki Mizoguchi