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Apparatus for compensating of phase rotation in a final amplifier stage

  • US 5,483,681 A
  • Filed: 08/24/1993
  • Issued: 01/09/1996
  • Est. Priority Date: 08/24/1992
  • Status: Expired due to Term
First Claim
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1. Apparatus for compensating the phase rotation in the feedback loop of a cartesian feedback power amplifier in a transmitter final stage, comprisingmeans for quadrature modulation of a complex difference signal between a complex input signal and a corresponding complex feedback signal with a complex modulation signal for forming a modulated real valued first signal,means for quadrature demodulation of a real valued second signal, which is derived from an output signal from the power amplifier, and wherein said output signal is derived from said modulated real value first signal with a complex demodulation signal for forming the complex feedback signal,means for detecting a measure of a phase shift between the real valued first signal and the real valued second signal and between a quadrature component of the real valued first signal and the real valued second signal or a quadrature component of the real valued second signal and the real valued first signal, for determining a measure of the phase rotation of the feedback loop, andmeans for phase rotation of one of said complex modulation, demodulation, difference and feedback signals with a phase rotation compensating said determined phase rotation.

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