Patent ID: 6404823
Filing Date: 2002-06-11
Classification: H03F,H04B

Abstract:
An envelope feedforward power amplifier that provides high efficiency when amplifying signals having a non-constant envelope, comprising:an envelope extractor configured to separate an input signal into a first signal having a non constant envelope and a second signal having a constant envelope; a time delay operatively coupled to said envelope extractor and configured to delay said first signal to produce a delayed signal; a first amplifier operatively coupled to said time delay and configured to amplify said delayed signal to produce a modulation signal; an up-converter operatively coupled to said envelope extractor and configured to up-convert said second signal to a higher frequency to produce an up-converted signal, said up-converted signal having a substantially constant envelope; a second amplifier operatively coupled to said up-converter and configured to amplify said up-converted signal to produce a carrier signal, said second amplifier operating at a constant power level near saturation; and an envelope combiner operatively coupled to an output of said first amplifier and said second amplifier, said envelope combiner configured to use said modulation signal to amplitude modulate said carrier signal, said time delay configured to provide a time delay so that said modulation signal and said carrier signal arrive at said envelope combiner at substantially the same time.