Patents by Inventor Massaaki Ueki

Massaaki Ueki 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 analog converter
    Patent number: 5021788
    Abstract: A PWM digital-to-analog converter is disclosed in which a value representing a differential between a first pulse width modulated waveform based upon input digital data and a second pulse width modulated waveform representing a 2's complement version of the input digital data is produced by a differential amplifier and high frequency components thereof are attenuated to produce an analog output signal and with an improved distortion factor.
    Type: Grant
    Filed: February 13, 1990
    Date of Patent: June 4, 1991
    Assignee: Sony Corporation
    Inventors: Massaaki Ueki, Toshihiko Masuda, Takashi Kanai