Phase-modulated load apparatus and method
AssigneeFuturewei Technologies, Inc.
InventorsMunawar Kermalli, Zhengxiang Ma
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Abstract
Methods and apparatus are provided to improve the efficiency of an outphasing amplifier through modulating the phase angle of a reflected signal in the outphasing amplifier. An outphasing amplifier includes a first amplifier and a second amplifier. A circulator is provided having a first port coupled to an output of the outphasing amplifier, a second port coupled to a load and a third port coupled to a phase shifter. The phase shifter is configured to provide a different phase angle of a reflected signal from the phase shifter to the outphasing amplifier through the circulator.
Claims20
An apparatus comprising:
- an outphasing amplifier comprising a first amplifier and a second amplifier;
- and
- a circulator having a first port coupled to an output of the outphasing amplifier, a second port coupled to a load and a third port coupled to a phase shifter, wherein the phase shifter is configured, responsive to a control signal, to provide a different phase angle of a reflected signal from the phase shifter to the outphasing amplifier through the circulator, wherein the different phase angle is generated based upon a maximum efficiency envelope curve, wherein the maximum efficiency curve is formed by connecting maximum efficiency values of a group of curves, and wherein the group of curves include a first curve and second curve, and wherein the first curve is a curve of efficiency versus power when the load is a resistor and the second curve is a curve of efficiency versus power at a particular phase angle provided by the phase shifter.
A system comprising:
- a processor configured to generate a first constant-envelope signal and a second constant-envelope signal from an amplitude-modulated signal;
- an outphasing amplifier comprising a first amplifier and a second amplifier, wherein the first amplifier and the second amplifier receive the first constant-envelope signal and the second constant-envelope signal respectively;
- a circulator comprising:
- a first port coupled to an output of the outphasing amplifier;
- a second port coupled to a load;
- and
- a third port coupled to a phase shifter;
- and
- the phase shifter configured to provide a different phase angle of a reflected signal from the phase shifter to the outphasing amplifier through the circulator in response to a control signal, wherein the different phase angle is generated based upon a maximum efficiency curve, wherein the maximum efficiency curve is formed by connecting maximum efficiency values of a group of curves, and wherein at least one maximum efficiency value is not from a curve of efficiency versus power when the load is a resistor.
A method comprising:
- decomposing an amplitude-modulated signal into a first phase-modulated signal and a second phase-modulated signal;
- amplifying the first phase-modulated signal and the second phase-modulated signal to produce a first amplified signal and a second amplified signal through a first amplifier and a second amplifier respectively;
- combining the first amplified signal and the second amplified signal at an output of an outphasing amplifier, wherein the outphasing amplifier comprises the first amplifier and the second amplifier;
- and
- in response to a load variation, adjusting a phase angle of a reflected signal from a phase shifter to the outphasing amplifier, wherein the phase angle is generated based upon a maximum efficiency envelope curve, and wherein the method further comprises obtaining a phase angel value based upon the load variation and generating a control signal based upon the phase angle value, wherein the control signal is used to adjust the phase angle of the reflected signal from the phase shifter to the outphasing amplifier.
Dependencies are inferred from the claim text.