Patents by Inventor Norihisa Yamamoto

Norihisa Yamamoto 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: 5323242
    Abstract: In a video signal apparatus, a carrier signal generating circuit includes a VCO for generating a signal having a frequency at least twice that of a carrier signal necessary for conversion to a lower band with a sub-carrier in an NTSC system, a one-half divider circuit for dividing the VCO frequency signal by two, a delayed flip-flop circuit for receiving the divided signal and the sub-carrier signal to generate a difference frequency signal, a 1/40 divider circuit for dividing the Q output, a phase comparator circuit for comparing the phases of the 1/40 divided signal and the horizontal synchronizing signal to output a phase difference, a frequency discriminator circuit for comparing the phase of the flip-flop output with the frequency-divided output of the horizontal synchronizing signal to output a frequency error, and a circuit for converting the output of the phase comparator circuit and the frequency error into DC voltages and applying their sum as a control voltage for the VCO.
    Type: Grant
    Filed: January 12, 1990
    Date of Patent: June 21, 1994
    Assignees: Hitachi, Ltd., Hitachi Microcomputer Engineering, Ltd.
    Inventors: Norihisa Yamamoto, Hirokazu Kitamura, Katsuyoshi Yamashige, Takashi Kurihara, Tadashi Matsushima
  • Patent number: 4605901
    Abstract: A frequency-voltage converter comprising a feedback frequency generating means associated with controlled means, a saw-tooth wave generating means, a current source for the saw-tooth wave, pulse generating means and sample-and-hold means, the frequency-voltage converter being characterized by further provision of supply voltage switching means for changing the feedback frequency of the controlled means by changing the voltage to be supplied to the current source to change the current from the current source and to thereby the slope of the saw-tooth wave from the saw-tooth wave generating means.
    Type: Grant
    Filed: April 20, 1983
    Date of Patent: August 12, 1986
    Assignees: Hitachi, Ltd., Hitachi Microcomputer & Engineering, Ltd.
    Inventors: Yasunori Kobori, Isao Fukushima, Hideo Nishijima, Yoshinori Masuda, Norihisa Yamamoto