Patents by Inventor Keisuke Sakae

Keisuke Sakae 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: 5982836
    Abstract: A phase synchronizer is disclosed that provides a stable output signal while improving synchronization speed. The phase synchronizer includes one or two feedback circuits. The feedback circuit(s) includes a phase comparator for generating a pulse signal in accordance with a difference between the phases of an input signal and a feedback signal, a charge pump for converting the pulse signal supplied from the phase comparator to an analog voltage signal, a loop filter for removing high-frequency signal components from the analog voltage signal output from the charge pump and supplying as a filtered analog voltage signal (LF1 or LF2), and a voltage-controlled oscillator coupled to the loop filter for generating an oscillation output signal having a frequency which varies in accordance with the filtered analog signal (LF1 or LF2). The oscillation output signal is also supplied as the feedback signal to the phase comparator.
    Type: Grant
    Filed: April 2, 1997
    Date of Patent: November 9, 1999
    Assignee: Fujitsu Limited
    Inventors: Keisuke Sakae, Kimio Yoshikawa
  • Patent number: 5657359
    Abstract: A phase synchronizer is disclosed that provides a stable output signal while improving synchronization speed. The phase synchronizer includes one or two feedback circuits. The feedback circuit(s) includes a phase comparator for generating a pulse signal in accordance with a difference between the phases of an input signal and a feedback signal, a charge pump for converting the pulse signal supplied from the phase comparator to an analog voltage signal, a loop filter for removing high-frequency signal components from the analog voltage signal output from the charge pump and supplying as a filtered analog voltage signal (LF1 or LF2), and a voltage-controlled oscillator coupled to the loop filter for generating an oscillation output signal having a frequency which varies in accordance with the filtered analog signal (LF1 or LF2). The oscillation output signal is also supplied as the feedback signal to the phase comparator.
    Type: Grant
    Filed: November 2, 1995
    Date of Patent: August 12, 1997
    Assignee: Fujitsu, Limited
    Inventors: Keisuke Sakae, Kimio Yoshikawa