Patents by Inventor Isao Ikai

Isao Ikai 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).

  • Digital FM modulator using direct digital synthesizer
    Patent number: 5272454
    Abstract: A digital FM modulator includes an A/D converter, a multiplier, an adder, a direct digital synthesizer, and an addition data output circuit. The A/D converter digitally encodes an input modulation signal. The multiplier multiplies an output from the A/D converter and multiplication data input from an external circuit. The adder adds output data from the multiplier to addition data. The direct digital synthesizer changes an oscillation frequency on the basis of output data from the adder with respect to a reference frequency of a reference oscillator. The addition data output circuit changes the addition data to prevent a center frequency from changing in accordance with the multiplication data and outputs the addition data.
    Type: Grant
    Filed: August 14, 1992
    Date of Patent: December 21, 1993
    Assignees: NEC Corporation, Nippon Hoso Kyokai
    Inventors: Isao Ikai, Masatoshi Hamada, Yasuhiro Hasimoto, Yoshio Tachioka, Makoto Ishii