Patents by Inventor Takashi Asakura

Takashi Asakura 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: 4723308
    Abstract: An AM signal transmitter for generating an amplitude modulated carrier comprises a voltage-increasing stage and a power-increasing stage. The voltage-increasing stage includes a pulse width modulator, responsive to an input modulation signal, for producing a pair of high frequency pulse trains which are modulated in width in a complementary fashion. The pair of pulse trains are respectfully fed to a pair of switching and amplifying elements arranged in push-pull fashion. The output of the switching and amplifying elements is processed through a low pass filter to eliminate high frequency components, and is stepped up in voltage by processing through a voltage step-up transformer. The output of the voltage step-up transformer is then fed to the power stage of the AM signal transmitter, which include a power amplifier. Both the power amplifier and the switching and amplifying elements can be powered from a single power source. Other embodiments of the invention can be realized.
    Type: Grant
    Filed: January 6, 1986
    Date of Patent: February 2, 1988
    Assignee: NEC Corporation
    Inventors: Naoki Kobayashi, Takashi Asakura, Hideo Sato