A power encoder includes an amplitude-phase splitter for splitting an input signal into an envelope signal and a phase modulated signal, and a pre-distortion unit for distorting the envelope signal using a look-up table (LUT) to produce a distorted envelope signal. The power encoder also includes a digital converter for combining the distorted envelope signal with the phase modulated signal to produce a distorted input signal, a pulse width modulator (PWM) for modulating the distorted input signal according to the transformation function to produce a modulated signal, and a switch mode power amplifier for amplifying the modulated signal. The look-up table stores a non-linear mapping of a transformation function and a relationship between the distorted input signal and the modulated signal is non-linear.