Abstract: Distortion introduced in phase modulated RF signals by amplifiers and other signal processors is substantially reduced by modifying complex modulating signals I,Q in a way that compensates for the amplifier phase error .phi..sub.e as a function of amplifier power P. In a preferred embodiment, I, Q are combined to calculate the amplifier power level and scaled by a parameter, e.g., K1=-d.phi..sub.e /dP, to provide factor B so that compensated signals I"=AQ+BI and Q"=AI-BQ, where A is a constant, can be determined. When an RF carrier modulated by I", Q" is passed through the distorting amplifier the amplifier induced distortion is cancelled. Substantial reduction in bit error probability is obtained. The method can also be used for post-distortion correction.