Patents by Inventor Li-Cheng R. Zai

Li-Cheng R. Zai 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: 6429775
    Abstract: An apparatus, method, and system are provided for sending radio frequency (RF) power to RF transponders (RFID tags), wherein the frequency sent to the tags is changed very rapidly.
    Type: Grant
    Filed: September 11, 2000
    Date of Patent: August 6, 2002
    Assignee: Intermec IP Corp.
    Inventors: Rene D. Martinez, Harley Kent Heinrich, Paul J. Sousa, Li-Cheng R. Zai
  • Patent number: 5635848
    Abstract: A digital and analog controller for controlling a high-speed probe actuator is disclosed. This method and system provide the probe actuator system with improved damping ratio and reduced impact force, so the throughput of the tester is increased with fast settling actuator armature. With this method and system, the steady-state probe force is less sensitive to the servo system, test probe and variation in the probing distance d. An electronic circuit, which consists of analog operational amplifiers, monostable multivibrators, and D flip-flops, is presented for low-cost applications.
    Type: Grant
    Filed: March 10, 1995
    Date of Patent: June 3, 1997
    Assignee: International Business Machines Corporation
    Inventors: James M. Hammond, James C. Mahlbacher, Kenneth G. Roessler, Michael Servedio, Li-Cheng R. Zai
  • Patent number: 5541520
    Abstract: A method and apparatus for determining when transient responses of a signal have ended. A plurality of filters is provided. Operation of success of filters is cause to begin at successive times. The convergence of the outputs of the various filters is then tested. When convergence is detected, the signal provided by the first started filter of the successive filters that indicated convergence is used as an output signal. The signal is typically an electronic module test signal from an electronic module. Testing for convergence is performed by averaging outputs of each filter started to determine an average value; determining a deviation of each output of the filters from the average value; totaling the deviation to determine a total deviation; and comparing the total deviation to a reference level. Preferably, the total deviation is integrated over a period of time to provide an integrated total deviation; and the integrated total derivation is compared to the reference level.
    Type: Grant
    Filed: October 31, 1994
    Date of Patent: July 30, 1996
    Assignee: International Business Machines Corporation
    Inventors: Li-Cheng R. Zai, Shaul Halevi
  • Patent number: 5515366
    Abstract: Direct communication between a primary portable unit initiating the communication and a secondary portable unit is established utilizing two handshaking operations. The first handshaking operation is performed in the base station channel to establish initial contact between the primary and secondary portable units. After initial contact is made, the second handshaking operation is performed to establish communication in an unoccupied channel. The base station channel and the unoccupied channel may be a TDMA/TDD channel or a TDMA/FDD channel.
    Type: Grant
    Filed: November 17, 1994
    Date of Patent: May 7, 1996
    Assignee: International Business Machines Corporation
    Inventors: Trieu C. Chieu, Anand Narasimhan, Gary E. O'Neil, Li-Cheng R. Zai