Patents by Inventor Weihua Chen

Weihua Chen 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: 7675285
    Abstract: An apparatus includes a sense element and an oscillator. The oscillator is coupled to the sense element and is used to generate an oscillator signal and a gain control signal. The oscillator signal is amplitude compensated when noise is detected in the sense element. A method includes detecting magnetic interference in a sense element coupled to an oscillator, and adjusting a gain control signal in the oscillator to compensate for the magnetic interference.
    Type: Grant
    Filed: September 9, 2004
    Date of Patent: March 9, 2010
    Assignee: Rockwell Automation Technologies, Inc.
    Inventors: Weihua Chen, Saeed Shafiyan-Rad
  • Publication number: 20090140727
    Abstract: An inductive proximity sensor is disclosed. The proximity sensor includes a source circuit with an inductive element configured to deliver energy to a resonator when a source current is changed. In various embodiments, the source current is provided a step current source. In various embodiment, the source current is provided by constant current source coupled to the inductive element by a switch. Apparatus and methods for operating the inductive proximity sensor are disclosed.
    Type: Application
    Filed: November 29, 2007
    Publication date: June 4, 2009
    Inventors: George E. Rollins, Weihua Chen, Prachi S. Kulkarni, Diana A. Sufariu
  • Publication number: 20090085560
    Abstract: An inductive proximity sensor is disclosed. The proximity sensor includes a housing having at least a first pair of inductive coils disposed within the housing. One of the first pair of inductive coils is opposite in polarity from another one of the first pair of inductive coils. The sensor optionally includes a second set of inductive coils, having opposite polarity.
    Type: Application
    Filed: September 28, 2007
    Publication date: April 2, 2009
    Inventors: George E. Rollins, Weihua Chen, Prachi S. Kulkarni, Diana A. Sufariu
  • Publication number: 20090052660
    Abstract: This invention provides a method for encrypting and decrypting Instant Messaging data. A client encrypts Instant Messaging data using a data encryption key and transmits the data encryption key to a server; the server encrypts the data encryption key using a uniform server key and transmits the encrypted data encryption key to the client. When the server needs to assist with decryption, the client transmits to the server a data encryption key encrypted using a uniform server key; the server acquires the data encryption key and transmits it to the client; the client decrypts Instant Messaging data locally stored using the data encryption key. By embodiments of this invention, server doesn't need to store one key for encrypting and decrypting data encryption key for each client, only needs to store a uniform server key, thereby saving storage spaces of server, and reducing the burden of server performing encrypting and decrypting.
    Type: Application
    Filed: October 28, 2008
    Publication date: February 26, 2009
    Applicant: TENCENT TECHNOLOGY (SHENZHEN) COMPANY LIMITED
    Inventors: Weihua Chen, Ziguang Gao, Mao Ye
  • Publication number: 20080174373
    Abstract: A phase-locked loop employing a plurality of oscillator complexes is disclosed. The phase-locked loop includes a clock output and a plurality of oscillator complexes operable to generate output signals. The phase-locked loop further includes control logic which is configured to selectively couple an output signal of one of the plurality of oscillator complexes to the clock output.
    Type: Application
    Filed: January 19, 2007
    Publication date: July 24, 2008
    Inventors: Liang Dai, Brandon Wayne Lewis, Jeffrey Todd Bridges, Weihua Chen
  • Patent number: 7274189
    Abstract: An apparatus includes a first circuit, a second circuit, and a capacitor. The first circuit includes a sense element. The capacitor couples the first circuit to the second circuit. The first feedback path couples the second circuit to the first circuit. And the second feedback path couples the second circuit to the first circuit. A method includes generating, for an oscillator signal having an amplitude and a gain, a substantially direct current signal related to an amplitude, and controlling the gain with the substantially direct current signal.
    Type: Grant
    Filed: September 9, 2004
    Date of Patent: September 25, 2007
    Assignee: Rockwell Automation Technologies, Inc.
    Inventors: Weihua Chen, Saeed Shafiyan-Rad
  • Publication number: 20060061351
    Abstract: An apparatus includes a sense element and an oscillator. The oscillator is coupled to the sense element and is used to generate an oscillator signal and a gain control signal. The oscillator signal is amplitude compensated when noise is detected in the sense element. A method includes detecting magnetic interference in a sense element coupled to an oscillator, and adjusting a gain control signal in the oscillator to compensate for the magnetic interference.
    Type: Application
    Filed: September 9, 2004
    Publication date: March 23, 2006
    Inventors: Weihua Chen, Saeed Shafiyan-Rad
  • Publication number: 20060049827
    Abstract: An apparatus includes a first circuit, a second circuit, and a capacitor. The first circuit includes a sense element. The capacitor couples the first circuit to the second circuit. The first feedback path couples the second circuit to the first circuit. And the second feedback path couples the second circuit to the first circuit. A method includes generating, for an oscillator signal having an amplitude and a gain, a substantially direct current signal related to an amplitude, and controlling the gain with the substantially direct current signal.
    Type: Application
    Filed: September 9, 2004
    Publication date: March 9, 2006
    Inventors: Weihua Chen, Saeed Shafiyan-Rad
  • Patent number: 5681111
    Abstract: A method and apparatus for determining the temperature of an environment at an elevated temperature (i.e., one exceeding about 300.degree. C.) wherein oxides that do not melt at such temperatures, do not age significantly at such temperatures and which have a sensitivity for such measurements are employed as thermistor resistors. Such oxides are calcium zirconate, yttria, alumina, dysprosia, magnesia, the oxide combinations alumina-silica, zirconia-silica and titania-silica. Measurements in electric current change is preferably the measurement of alternating current rather than the conventional dc current. A particularly useful instrument for such measurements consists of such a resistor with a laminate of connector metal such as diffusion bonded precious metal sheets or foils on separated surface areas as electrode connectors.
    Type: Grant
    Filed: June 17, 1994
    Date of Patent: October 28, 1997
    Assignee: The Ohio State University Research Foundation
    Inventors: Sheikh A. Akbar, Weihua Chen, Virginia D. Patton, Ching C. Wang