Patents by Inventor R. Andrew Hatfield

R. Andrew Hatfield 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).

  • Spectrum analyzer and logarithmic amplifier therefor
    Patent number: 4812772
    Abstract: The spectrum analyzer comprises an input for receiving eletromagnetic signals in a predetermined first frequency band and an image reject mixer for reducing the power of images of the received signals while down-converting the signals to an intermediate frequency. The image reject mixer reduces the signal power level to approximately that of the background noise of the signal. The mixer is swept through a predetermined frequency band in order to down-convert each frequency in the received signal band individually. The down-converted signals are logarithmically compressed using a multi-stage logarithmic compression circuit having variable gain amplifiers in each stage.
    Type: Grant
    Filed: October 7, 1987
    Date of Patent: March 14, 1989
    Assignee: AVCOM of Virginia, Inc.
    Inventor: R. Andrew Hatfield
  • Spectrum analyzer and logarithmic amplifier therefor
    Patent number: 4720673
    Abstract: The spectrum analyzer comprises an input for receiving electromagnetic signals in a predetermined first frequency band and an image reject mixer for reducing the power of images of the received signals while down-converting the signals to an intermediate frequency. The image reject mixer reduces the signal power level to approximately that of the background noise of the signal. The mixer is swept through a predetermined frequency band in order to down-convert each frequency in the received signal band individually. The down-converted signals are logarithmically compressed using a multi-stage logarithmic compression circuit having variable gain amplifiers in each stage.
    Type: Grant
    Filed: May 15, 1985
    Date of Patent: January 19, 1988
    Assignee: Avcom of Virginia, Inc.
    Inventor: R. Andrew Hatfield