Patents by Inventor James N. Liu

James N. Liu 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).

  • Measuring noise figure and y-factor
    Patent number: 5191294
    Abstract: Apparatus for measuring the noise parameters of a device under test (DUT), with full compensation for impedance mismatches between the DUT and the test apparatus. The apparatus includes an S-parameter measuring device, such as vector network analyzer (VNA), combined with a noise module. The noise module includes, among other things, a pair of test ports for the DUT, a noise source which can be turned on or off by an external controller, a receiver, and a switch for coupling the output of the DUT to selectably either the receiver or port 2 of the VNA.
    Type: Grant
    Filed: July 21, 1992
    Date of Patent: March 2, 1993
    Assignee: Wiltron Company
    Inventors: Martin I. Grace, Donald A. Bradley, James N. Liu