Patents by Inventor Zhiwei Xu

Zhiwei Xu 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).

  • Publication number: 20060014509
    Abstract: A system or method for a circuit network that receives an RF signal, and where a plurality of switching transistors receive an RF signal output by the circuit network and perform mixing with a local oscillation (LO) signal received on a LO input. An active bias circuit performs active bias of the plurality of switching transistors in a feedback loop provided between the LO input and an output of the plurality of switching transistors.
    Type: Application
    Filed: July 14, 2004
    Publication date: January 19, 2006
    Inventors: Zhiwei Xu, Pei-Ming Chow, Mau-Chung Chang
  • Publication number: 20060009171
    Abstract: A system or method for calibrating an RF transmitter includes inputting a test tone to the RF transmitter. LO leakage calibration is performed on an output of the RF transmitter with the test tone inputted thereto, in order to determine a minimum LO leakage. Thereafter, sideband image calibration is performed on the output of the RF transmitter with the test tone inputted thereto, in order to determine a minimum sideband image. Operational values for the RF transmitter are stored in memory based on the detected minimum LO leakage and the detected minimum sideband image, to be used during a normal operation mode of the RF transmitter.
    Type: Application
    Filed: July 9, 2004
    Publication date: January 12, 2006
    Inventors: Zhiwei Xu, Shan Jiang, Charles Chien
  • Publication number: 20060006951
    Abstract: A system or method for controlling a voltage controlled oscillator (VCO) or LO buffer includes an amplitude detector for detecting an amplitude value at a node corresponding to the at least one output line. A comparator compares the detected amplitude value with a predetermined amplitude value, and outputs a first digital value when the detected amplitude value is greater than the predetermined amplitude value, and a second digital value when the detected amplitude value is less than the predetermined amplitude value. An accumulator accumulates outputs of the comparator so as to provide an accumulated digital amplitude value. A digital-to-analog converter converts the accumulated digital amplitude value to an accumulated analog amplitude value. The analog accumulated amplitude value is provided as an updated bias control signal to the bias transistor of the VCO or LO buffer.
    Type: Application
    Filed: July 9, 2004
    Publication date: January 12, 2006
    Inventors: Zhiwei Xu, Yi-Cheng Wu, Mau-Chung Chang
  • Publication number: 20060009180
    Abstract: A calibration system for an RF system that includes an RF receiver capable of operating in a normal mode and in a calibration mode. The calibration system includes a phase delay unit provided on at least one of an I channel output and a Q channel output of the RF receiver. The system further includes a phase detector configured to detect a phase difference between the I channel output of the RF receiver and the Q channel output of the RF receiver. The system also includes a calibration control unit configured to provide a digital calibration control signal to the RF receiver based on the phase difference as provided by the phase detector.
    Type: Application
    Filed: July 9, 2004
    Publication date: January 12, 2006
    Inventors: Zhiwei Xu, Shan Jiang, Charles Chien
  • Publication number: 20050206402
    Abstract: Various methods and systems for determining one or more properties of a specimen are provided. One system for determining a property of a specimen is configured to illuminate a specimen with different wavelengths of light substantially simultaneously. The different wavelengths of light are modulated at substantially the same frequency. The system is also configured to perform at least two measurements on the specimen. A minority carrier diffusion length of the specimen may be determined from the measurements and absorption coefficients of the specimen at the different wavelengths. Another system for detecting defects on a specimen is configured to deposit a charge at multiple locations on an upper surface of the specimen. This system is also configured to measure a vibration of a probe at the multiple locations. Defects may be detected on the specimen using a two-dimensional map of the specimen generated from the measured surface voltages.
    Type: Application
    Filed: March 10, 2005
    Publication date: September 22, 2005
    Inventors: Jianou Shi, Jeffrey Rzepiela, Shiyou Pei, Zhiwei Xu, John Alexander
  • Patent number: 6759255
    Abstract: A method to detect metal contamination on a semiconductor topography is provided. The semiconductor topography may include a semiconductor substrate or a dielectric material disposed upon a semiconductor substrate. The metal contamination may be driven into the semiconductor substrate by an annealing process. Alternatively, the annealing process may drive the metal contamination into the dielectric material. Subsequent to the annealing process, a charge may be deposited upon an upper surface of the semiconductor topography. An electrical property of the semiconductor topography may be measured. A characteristic of at least one type of metal contamination may be determined as a function of the electrical property of the semiconductor topography. The method may be used to determine a characteristic of one or more types of metal contamination on a portion of the semiconductor topography or the entire semiconductor topography.
    Type: Grant
    Filed: May 10, 2001
    Date of Patent: July 6, 2004
    Assignee: KLA-Tencor Technologies Corp.
    Inventors: Zhiwei Xu, Arun Srivatsa, Amin Samsavar, Thomas G Miller, Greg Horner, Steven Weinzierl
  • Publication number: 20020090746
    Abstract: A method to detect metal contamination on a semiconductor topography is provided. The semiconductor topography may include a semiconductor substrate or a dielectric material disposed upon a semiconductor substrate. The metal contamination may be driven into the semiconductor substrate by an annealing process. Alternatively, the annealing process may drive the metal contamination into the dielectric material. Subsequent to the annealing process, a charge may be deposited upon an upper surface of the semiconductor topography. An electrical property of the semiconductor topography may be measured. A characteristic of at least one type of metal contamination may be determined as a function of the electrical property of the semiconductor topography. The method may be used to determine a characteristic of one or more types of metal contamination on a portion of the semiconductor topography or the entire semiconductor topography.
    Type: Application
    Filed: May 10, 2001
    Publication date: July 11, 2002
    Inventors: Zhiwei Xu, Arun Srivatsa, Amin Samsavar, Thomas G. Miller, Greg Horner, Steven Weinzierl
  • Patent number: 6157135
    Abstract: A lighting device including a temperature sensing device for controlling the operation of the light emitting device. The lighting device includes a housing, a reflector coupled to the housing, a bulb received in the housing, the bulb being connected to a source of electrical power, and a capillary tube thermostat received in the housing. The capillary tube is an elongated metal member having a hollow center filled with a vacuum charged fluid. The fluid is calibrated to open the thermostat between 150.degree. F. and 350.degree. F. The capillary tube thermostat is in electrical communication with the power source and is supported by the housing in thermal communication with the bulb. The thermostat extends along at least a portion of the length of the bulb. The thermostat is also in thermal communication with the reflector, and thus will open the thermostat contacts if an overheat condition is detected at either the bulb or the reflector.
    Type: Grant
    Filed: January 15, 1999
    Date of Patent: December 5, 2000
    Inventors: Zhiwei Xu, Peisheng Qian
  • Patent number: D437963
    Type: Grant
    Filed: October 14, 1999
    Date of Patent: February 20, 2001
    Assignee: Beme International LLC
    Inventors: Zhiwei Xu, Brian Graves, Joseph Manno
  • Patent number: D438323
    Type: Grant
    Filed: October 14, 1999
    Date of Patent: February 27, 2001
    Assignee: Beme International LLC
    Inventors: Zhiwei Xu, Brian Graves, Joseph Manno
  • Patent number: D443098
    Type: Grant
    Filed: October 14, 1999
    Date of Patent: May 29, 2001
    Assignee: Beme International LLC
    Inventors: Zhiwei Xu, Brian Graves, Joseph Manno
  • Patent number: D443379
    Type: Grant
    Filed: October 14, 1999
    Date of Patent: June 5, 2001
    Assignee: Beme International LLC
    Inventors: Zhiwei Xu, Brian Graves, Joseph Manno
  • Patent number: D432005
    Type: Grant
    Filed: November 17, 1999
    Date of Patent: October 17, 2000
    Assignee: Beme International LLC
    Inventors: Zhiwei Xu, Brian Graves
  • Patent number: D432398
    Type: Grant
    Filed: August 18, 1999
    Date of Patent: October 24, 2000
    Assignee: Beme International LLC
    Inventors: Brain Graves, Zhiwei Xu
  • Patent number: D432399
    Type: Grant
    Filed: November 17, 1999
    Date of Patent: October 24, 2000
    Assignee: Beme International LLC
    Inventors: Zhiwei Xu, Brian Graves
  • Patent number: D433317
    Type: Grant
    Filed: August 18, 1999
    Date of Patent: November 7, 2000
    Assignee: Beme International LLC
    Inventors: Brain Graves, Zhiwei Xu
  • Patent number: D433620
    Type: Grant
    Filed: November 17, 1999
    Date of Patent: November 14, 2000
    Assignee: Beme International LLC
    Inventors: Zhiwei Xu, Brian Graves
  • Patent number: D433925
    Type: Grant
    Filed: August 18, 1999
    Date of Patent: November 21, 2000
    Assignee: Beme International LLC
    Inventors: Brian Graves, Zhiwei Xu
  • Patent number: D434643
    Type: Grant
    Filed: August 18, 1999
    Date of Patent: December 5, 2000
    Assignee: Beme International LLC
    Inventors: Brain Graves, Zhiwei Xu
  • Patent number: D434973
    Type: Grant
    Filed: November 17, 1999
    Date of Patent: December 12, 2000
    Assignee: Beme International LLC
    Inventors: Zhiwei Xu, Brian Graves