Patents by Inventor Seiichi Ishizaki

Seiichi Ishizaki 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).

  • Filter unit, mobile communication terminal test system, and mobile communication terminal test method
    Patent number: 8805311
    Abstract: [Problem] To provide a band stop filter unit, a mobile communication terminal test system, and a mobile communication terminal test method that are flexibly adaptable to the addition/change of a specification in a frequency band for mobile communication. [Means for Resolution] There are provided a first variable filter (102) and a second variable filter (103) which are connected to each other in series, respectively have YIG elements to vary tuning frequencies (f1 and f2), and attenuate the desired signal within predetermined bandwidths (?BW1 and ?BW2) having centers of the tuning frequencies. The tuning frequency (f1) and the tuning frequency (f2) are controlled to be the same as each other or around each other when the desired signal is located at a low frequency band side.
    Type: Grant
    Filed: August 26, 2010
    Date of Patent: August 12, 2014
    Assignee: Anritsu Corporation
    Inventors: Tomohiko Maruo, Hiroshi Watanabe, Seiichi Ishizaki
  • FILTER UNIT, MOBILE COMMUNICATION TERMINAL TEST SYSTEM, AND MOBILE COMMUNICATION TERMINAL TEST METHOD
    Publication number: 20110053622
    Abstract: [Problem] To provide a band stop filter unit, a mobile communication terminal test system, and a mobile communication terminal test method that are flexibly adaptable to the addition/change of a specification in a frequency band for mobile communication. [Means for Resolution] There are provided a first variable filter (102) and a second variable filter (103) which are connected to each other in series, respectively have YIG elements to vary tuning frequencies (f1 and f2), and attenuate the desired signal within predetermined bandwidths (?BW1 and ?BW2) having centers of the tuning frequencies. The tuning frequency (f1) and the tuning frequency (f2) are controlled to be the same as each other or around each other when the desired signal is located at a low frequency band side.
    Type: Application
    Filed: August 26, 2010
    Publication date: March 3, 2011
    Applicant: ANRITSU CORPORATION
    Inventors: Tomohiko Maruo, Hiroshi Watanabe, Seiichi Ishizaki