Extraction Apparatus of Phase and Amplitude Error in Linear Power Amplifier

摘要

PURPOSE: An apparatus for extracting error of phase and amplitude from a linear power amplifier is provided to increase the efficiency of the LPA(Linear Power Amplifier) by eliminating an error amplifier required in a feedforward manner. CONSTITUTION: A pre-amplifier(1) amplifies a weak RF(Radio Frequency) signal up to a proper level. A first directional coupler(2) distributes the signal to a first main amplifier(3) and a delay line(8). First and second main amplifiers(3,15) amplify signals inputted through the first directional coupler(2) and a third vector modulator. A second directional coupler(4) distributes the signal amplified through the first main amplifier(3) to a second delay line(5) and a second vector modulator(9). The first and second delay lines(8,5) compensate time delay of the signals outputted from the pre-amplifier(1) and the first main amplifier(3). A first distributer(10) distributes the signal passing through the first delay line(8). A second distributer(11) couples the signal distributed from the first distributer(10) and the signal inputted through the second directional coupler(4) and the second vector modulator(9). A third distributer(13) couples the signal distributed from the first distributer(10) and the output signal of the second distributer(11). First to third vector modulators(12,9,14) simultaneously control the amplitude and phase of the signals under the control of a control board(16). A 90-degree hybrid coupler(6) receives the signals from the second delay line(5) and the second main amplifier(15) and outputs a main signal and an error signal on a separated output port. An isolator(7) blocks that a signal on an output signal of a 90-degree hybrid coupler is inputted to an LPA.