The controller controls the amplifier and a modulated power supply, supplying power to the amplifier, by detecting an RF envelope of a signal input to the amplifier. Predistortion of the amplifier synchronous with changes of bias is provided using a look-up table. Specifically, amplitude predistortion, phase predistortion and DC voltage level adjustments are made to the RF signal. Adjustments for gain and phase variation are applied synchronously with bias changes.