Patents by Inventor Hideki Yamashita

Hideki Yamashita 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: 6819188
    Abstract: A phase-locked loop oscillator with loop gain compensation. The phase-locked loop oscillator includes a phase comparator, a loop filter, a voltage-controlled oscillator, a control device, and a variable-gain amplifier disposed between the phase comparator and the loop filter. The oscillator detects the output signal voltage of the loop filter and controls the amplification rate of the variable-gain amplifier so that the loop gain is compensated and held constant, without sacrificing continuity.
    Type: Grant
    Filed: November 26, 2002
    Date of Patent: November 16, 2004
    Assignee: Agilent Technologies, Inc.
    Inventor: Hideki Yamashita
  • Publication number: 20040223566
    Abstract: A data transmission system with which optimal skew adjustment is achieved by a structure transmitting skew adjustment signals in place of data signals and detecting the amount of skew between the clock signals and the data signals. The skew adjustment signals are alternating signals with twice the period of the clock signals, and one signal state persists for a longer time than the other signal state.
    Type: Application
    Filed: January 30, 2004
    Publication date: November 11, 2004
    Applicant: AGILENT TECHNOLOGIES, INC.
    Inventor: Hideki Yamashita
  • Publication number: 20030098745
    Abstract: A phase-locked loop oscillator with loop gain compensation. The phase-locked loop oscillator includes a phase comparator, a loop filter, a voltage-controlled oscillator, a control device, and a variable-gain amplifier disposed between the phase comparator and the loop filter. The oscillator detects the output signal voltage of the loop filter and controls the amplification rate of the variable-gain amplifier so that the loop gain is compensated and held constant, without sacrificing continuity.
    Type: Application
    Filed: November 26, 2002
    Publication date: May 29, 2003
    Applicant: Agilent Technologies, Inc.
    Inventor: Hideki Yamashita
  • Patent number: 6316943
    Abstract: Apparatus is described for generating a frequency-sweepable measurement signal and a local signal with a frequency separated from the measurement signal frequency by an intermediate frequency. The measurement signal and a local signal are generated by a simple structure, including a high-frequency variable-frequency signal source, a low-frequency fixed-frequency signal source, a first frequency divider and a second frequency divider. The variable-frequency signal source is a sweepable signal source. The first frequency divider divides an output frequency fa from the variable-frequency signal source by n and outputs a measurement signal with a frequency of fa/n. The signal of the variable-frequency signal source is also applied to the first input of the second frequency divider, and the signal of fixed-frequency signal source, with a frequency of fb, is applied to the second input.
    Type: Grant
    Filed: December 22, 1999
    Date of Patent: November 13, 2001
    Assignee: Agilent Technologies, Inc.
    Inventors: Hideki Yamashita, Kazuyuki Yagi
  • Patent number: 6028425
    Abstract: Apparatus is described for generating a frequency-sweepable measurement signal and a local signal with a frequency separated from the measurement signal frequency by an intermediate frequency. The measurement signal and a local signal are generated by a simple structure, including a high-frequency variable-frequency signal source, a low-frequency fixed-frequency signal source, a first frequency divider and a second frequency divider. The variable-frequency signal source is a sweepable signal source. The first frequency divider divides an output frequency fa from the variable-frequency signal source by n and outputs a measurement signal with a frequency of fa/n. The signal of the variable-frequency signal source is also applied to the first input of the second frequency divider, and the signal of fixed-frequency signal source, with a frequency of fb, is applied to the second input.
    Type: Grant
    Filed: January 13, 1997
    Date of Patent: February 22, 2000
    Assignee: Hewlett-Packard Company
    Inventors: Hideki Yamashita, Kazuyuki Yagi
  • Patent number: 5929670
    Abstract: A method for improving the precision of a signal generator utilizing counters. The difference between an external standard signal frequency and an internal standard frequency is measured by digital counters. The signal of this internal standard frequency signal source is counted by a first counter and the frequency of an external standard frequency signal source is counted by a second counter. A calculating and control part determines the accurate frequency of internal standard frequency signal source from count values of both counters. The measurement frequency signal source generates a signal with the desired frequency. The circuit is digitally implemented.
    Type: Grant
    Filed: January 13, 1997
    Date of Patent: July 27, 1999
    Assignee: Hewlett-Packard Company
    Inventor: Hideki Yamashita
  • Patent number: 5746282
    Abstract: A power-assisted cart includes a wheeled platform for supporting a load thereon; driving wheels mounted on the wheeled platform for, when driven, moving the wheeled platform; a drive unit for driving the driving wheels; an operating unit which may be in the form of a handle mounted on the wheeled platform for receiving an external force applied thereto when the cart is desired to be moved; a force detector for detecting a magnitude and direction of the external force applied to the operating unit; and a control for generating to the drive unit an output substantially proportional to the external force detected by the force detector.
    Type: Grant
    Filed: April 12, 1996
    Date of Patent: May 5, 1998
    Assignee: Matsushita Electric Works, Ltd.
    Inventors: Shigeki Fujiwara, Hideki Yamashita, Hiroshi Maeda
  • Patent number: 5321364
    Abstract: A network analyzer having .means for determining the type and element values of a hypothetical lossless matching circuit for a device under test (DUT) and for computing and displaying S parameters of the DUT in combination with the matching circuit.
    Type: Grant
    Filed: November 6, 1992
    Date of Patent: June 14, 1994
    Assignee: Hewlett Packard Company
    Inventors: Akira Nukiyama, Hideki Yamashita