Patents by Inventor Thomas R. Tullsen

Thomas R. Tullsen 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).

  • Bipolar voltage to frequency converter
    Patent number: 4839788
    Abstract: A bipolar voltage to frequency converter which utilizes a single operational amplifier for generating appropriate signals representative of the frequency and signs of a bipolar input signal. The present invention has applications in chemical chromatography, absorption meters and data acquisition systems.
    Type: Grant
    Filed: January 29, 1988
    Date of Patent: June 13, 1989
    Assignee: Dionex Corporation
    Inventor: Thomas R. Tullsen
  • Chromatographic optical detector with logarithmic calibration circuit
    Patent number: 4700059
    Abstract: An optical detector is provided. The optical detector provides automatic zeroing of a logarithmic ration function in applications such as absorption meters, fluorometers and other chromatographic techniques.
    Type: Grant
    Filed: March 13, 1986
    Date of Patent: October 13, 1987
    Assignee: Dionex Corporation
    Inventor: Thomas R. Tullsen