Patents by Inventor Tetsuo Igawa

Tetsuo Igawa 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: 4659999
    Abstract: In a signal generator based on Direct Frequency Synthesis, a first reference frequency generator generates a signal of a reference frequency. A plurality of second reference frequency generators, respectively, generates K signals with different frequencies Asin(.omega..sub.1 t+.psi.), Asin(.omega..sub.2 t+.psi.) . . . Asin(.omega..sub.K t+.psi.), which are in phase at time point (t=0), in response to the output signal of the first reference frequency generator. A switching circuit selectively switches the output signals from the plurality of said second reference frequency generators. A timing pulse generator generates timing pulses to operate said switching circuit at time T as given by .vertline..omega..sub.i+1 T-.omega..sub.i T.vertline.=2l.pi. (l:integer) where i=1, 2 . . . K-1.
    Type: Grant
    Filed: October 24, 1984
    Date of Patent: April 21, 1987
    Assignee: Anritsu Electric Company Limited
    Inventors: Hatsuo Motoyama, Tetsuo Igawa