Patents by Inventor Augustin P. Chang

Augustin P. Chang 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).

  • High linearity multicarrier RF amplifier
    Patent number: 6504428
    Abstract: A hybrid multicarrier RF power amplifier linearization architecture combines ACT and feed-forward amplifier stages to achieve high output distortion rejection and enhanced amplifier linearity. A carrier cancellation loop is coupled with a main RF power amplifier stage having parallel RF power amplifiers coupled via intermod-complementing predistortion paths. The carrier cancellation loop is coupled to a feed-forward loop containing a feed-forward RF power amplifier, to produce a composite amplified output signal having very reduced intermodulation products. Vector modulators in the main amplifier and feed-forward amplifier stages are controlled by a digital signal processor, using outputs from various monitoring subsystems, including pilot tone detection, correlator, distortion and power detector circuits.
    Type: Grant
    Filed: May 16, 2001
    Date of Patent: January 7, 2003
    Assignee: Spectrian Corporation
    Inventors: Armando C. Cova, Emil J. Crescenzi, Jr., Augustin P. Chang, Stephen J. Foley
  • High linearity multicarrier RF amplifier
    Publication number: 20020008577
    Abstract: A hybrid multicarrier RF power amplifier linearization architecture combines ACT and feed-forward amplifier stages to achieve high output distortion rejection and enhanced amplifier linearity. A carrier cancellation loop is coupled with a main RF power amplifier stage having parallel RF power amplifiers coupled via intermod-complementing predistortion paths. The carrier cancellation loop is coupled to a feed-forward loop containing a feed-forward RF power amplifier, to produce a composite amplified output signal having very reduced intermodulation products. Vector modulators in the main amplifier and feed-forward amplifier stages are controlled by a digital signal processor, using outputs from various monitoring subsystems, including pilot tone detection, correlator, distortion and power detector circuits.
    Type: Application
    Filed: May 16, 2001
    Publication date: January 24, 2002
    Applicant: Spectrian Corporation
    Inventors: Armando C. Cova, Emil J. Crescenzi, Augustin P. Chang, Stephen J. Foley