Patent ID: 8026762
Filing Date: 2011-09-27
Classification: H03F

Abstract:
1. An amplifier, comprising: a signal separator for decomposing an input signal into at least two constant envelope signals; at least two amplifier circuits for amplifying the constant envelope signals; a combiner for combining the amplified constant envelope signals to form an output signal that is an amplified representation of the input signal; at least two linear correction circuits, wherein each linear correction circuit is configured to apply at least one of a gain, phase, or delay correction to a corresponding one of the constant envelope signals based upon a feedback portion of the output signal, said corrections being applied prior to amplifying the constant envelope signals; and at least two pre-distortion circuits, wherein each pre-distortion circuit is configured to apply a non-linear pre-distortion to a corresponding one of the constant envelope signals based upon the feedback portion of the output signal, said corrections being applied prior to amplifying the constant envelope signals, wherein each linear correction circuit is configured to apply said at least one gain, phase, or delay correction that is selected to minimize an error vector magnitude that is a waveform quality metric that measures a difference between the output signal of the combiner and the input signal, and wherein each pre-distortion circuit is configured to apply a non-linear pre-distortion that is selected to minimize the error vector magnitude, and wherein each pre-distortion circuit is configured to apply the non-linear pre-distortion to correct non-linear phase leading/lagging introduced by the combiner or other elements in the amplifier, and wherein the amplifier comprises at least two filters to filter the constant envelope signals following pre-distortion, and wherein each pre-distortion circuit is configured to apply the nonlinear pre-distortion to correct phase impairments introduced by said at least two filters.