Patents by Inventor Robert Ravoalavoson

Robert Ravoalavoson 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).

  • Digital method of correcting non-linearity in a transmission chain, and apparatus implementing the method
    Patent number: 5105446
    Abstract: The invention provide a digital method of correcting non-linearity in a transmission chain, in which the effects of amplifier non-linearities are compensated by applying predistortion in baseband prior to modulation, with the signal being processed digitally in real time. The invention also provides apparatus for implementing the method. The invention is particularly applicable to radio beams for conveying digital signals.
    Type: Grant
    Filed: October 5, 1990
    Date of Patent: April 14, 1992
    Assignee: Alcatel Transmission par Faisceaux Hertziens
    Inventors: Robert Ravoalavoson, Guy Allemand
  • Method of servo-controlling the parameters of a modulator having 2.sup.n phase and amplitude states, and a circuit for implementing the method
    Patent number: 5054037
    Abstract: Servo-controlling position in a modulator having 2.sup.n phase and amplitude states (used for e.g. 16-QAM radio beam transmission) is achieved by monitoring the amplitude of the signal output from the modulator. In a first or inner loop, any constellation centering error in the modulation states is corrected; in a second or middle loop, any quadrature error between the modulated carriers is corrected; and in a third or outer loop, any amplitude difference between the X and Y channels input to the modulator is corrected.
    Type: Grant
    Filed: January 18, 1990
    Date of Patent: October 1, 1991
    Assignee: Alcatel N.V.
    Inventors: Didier Martineau, Robert Ravoalavoson