Patents by Inventor Yutaka Umetsu

Yutaka Umetsu 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).

  • Communication system with a limited communication area
    Patent number: 4378602
    Abstract: In a communication system including communication transmitting means for modulating a carrier wave having a fixed frequency by a communication signal having communication content and for radiating the modulated signal wave, and receiving means for receiving the modulated signal radiated from the communication transmitting means to demodulate the communication signal, the communication system comprises a communication shielding area provided at a desired location on a boundary between communication areas for limiting the extent of the communication areas in which the modulated signal is transmitted, and shielding transmitting means for transmitting the shielding signal wave into said communication shielding area, the shielding signal wave being received by the receiving means tuned to the carrier wave frequency at a signal receiving level equal to or more than the receiving level of the modulated signal.
    Type: Grant
    Filed: June 4, 1980
    Date of Patent: March 29, 1983
    Assignee: Hochiki Corporation
    Inventors: Yutaka Umetsu, Takeshi Takeuchi