Apparatus for compensating of phase rotation in a final amplifier stage
First Claim
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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Abstract
An apparatus for compensating the phase rotation in the feedback loop of a cartesian feedback power amplifier in a final transmitter stage for quadrature modulation of the complex difference signal between a complex input signal and the corresponding complex feedback signal with a complex modulation signal for forming a modulated real valued first signal and for quadrature modulation of the output signal from the power amplifier with a complex demodulation signal for forming the complex feedback signal. The phase shift between the first signal and the second signal and between the quadrature component of the first signal and the second signal is detected for determining the phase rotation of the feedback loop. Furthermore, the phase rotation of the complex modulation signal can be changed with a compensating phase rotation defined by the determined phase rotation.
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Citations
12 Claims
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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, comprising
means 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, and means 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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7. Apparatus for compensating the phase rotation in a feedforward manner in a feedback loop of a cartesian feedback power amplifier in a transmitter final stage, comprising
means 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 modulated 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 rotation between the complex difference signal and the complex feedback signal, means for phase rotation of one of said complex modulation, demodulation, difference and feedback signals with a phase rotation counteracting said phase rotation in a feedforward manner.
Specification