Patents by Inventor Takehiro Futami

Takehiro Futami 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: 4091345
    Abstract: An electromechanical filter comprises a mechanical resonator, a pair of electromechanical transducers mechanically coupled to each other with the resonator interposed, and a pair of external matching circuits electrically connected to the respective transducers. Each matching circuit comprises a coil and a temperature-compensation capacitor connected to form a resonance circuit with the equivalent parallel capacitance of the associated transducer included therein. Resonant frequencies of the respective resonance circuits are rendered different from the passband center frequency of the filter. Preferably, the first-order temperature coefficients of the resonant frequency and the equivalent inductance of each transducer are selected to be (1) both negative and (2) positive and negative as the resonant frequency of the associated resonance circuit is rendered (1) higher and (2) lower than the center frequency.
    Type: Grant
    Filed: August 26, 1976
    Date of Patent: May 23, 1978
    Assignee: Nippon Electric Company, Ltd.
    Inventors: Takeshi Yano, Seiichiro Kanazawa, Takehiro Futami, Yasuyuki Ishiyama
  • Patent number: 3949326
    Abstract: Electromechanical filters of the type having a plurality of resonators coupled to each other by couplers which make it possible to provide a transmission frequency characteristic with finite-attenuation poles are disclosed. The filters have a first resonator disposed on the input side and a second resonator disposed on the output side of the filter. A plurality of third resonators, at least two in number, are disposed between the first and second resonators. The third resonators are coupled mechanically in parallel to the first and second resonators by a plurality of couplers so that one of the first and second resonators is in reverse phase relationship with one of the third resonators. Also, the coupling coefficients between the couplers differ from each other.
    Type: Grant
    Filed: February 27, 1975
    Date of Patent: April 6, 1976
    Assignee: Nippon Electric Company Limited
    Inventors: Takeshi Yano, Takehiro Futami, Seiichiro Kanazawa, Tetsuo Hayashi