Patent ID: 9054652
Filing Date: 2015-06-09
Classification: H03F,H04B

Abstract:
1. A method comprising: determining, estimating, or computing a coarse time delay represented by an integer T1; determining or selecting a current reference point for a transmitted signal waveform of an RF power amplifier; shifting the transmitted signal waveform by a set of offsets comprising a plurality of non-integer fractional steps from (T1−Xd) to (T1+Xd) where T1 is the integer and Xd is a non-integer fractional step size value for defining the plurality of non-integer fractional steps about the integer T1 such that the non-integer fractional steps progress in a positive direction as well as a negative direction from the integer T1; at each of the plurality of non-integer fractional steps, correlating the transmitted signal waveform with a feedback signal waveform to obtain a respective correlation value for each of corresponding fractional steps of the plurality of non-integer fractional steps; obtaining a correct fractional delay value by selecting a fractional step of the plurality of non-integer fractional steps having a highest respective correlation value; applying the obtained correct fractional delay value to the transmitted signal waveform to provide a compensated transmitted signal waveform, and combining the compensated transmitted signal waveform with the feedback signal waveform to reduce or eliminate at least one intermodulation product of the RF power amplifier.