A system (900, 1000, 1100) for power amplification of a radio-frequency signal, comprising: an IQ modulator configured to modulate an RF carrier signal based on a pair of IQ signals (908A,B) representative of at least the phase component of an original waveform to generate a phase-modulated RF signal (902, 1002, 1102); a fixed phase shifter (960, 1060) in communication with the IQ modulator and configured to generate a phase shift signal based on a phase characteristic of the phase-modulated RF signal (902, 1002, 1102); a feedback-controlled amplitude modulator (910, 1010, 1110) in communication with the IQ modulator and configured to modulate the phase-modulated RF signal (902, 1002, 1102) based on a feedback-corrected control signal to generate a modulated RF signal; a power amplifier (912, 1012, 1112) in communication with the amplitude modulator, wherein the power amplifier is configured to amplify the modulated RF signal and to generate an amplified RF output signal (904, 1004, 1104); an amplitude detector comprising an IQ demodulator (914, 1014) in communication with the power amplifier and the fixed phase shifter, wherein the fixed phase shifter is configured to receive the phase-modulated RF signal (902, 1002, 1102) from the IQ modulator and to synchronise a phase of the IQ modulator and a local oscillator of the IQ demodulator (914, 1014), and wherein the amplitude detector is configured to receive the phase shift signal, to detect an amplitude characteristic of the amplified RF output signal and to generate an amplitude feedback signal; and a feedback network (916, 1016, 1116) in communication with the amplitude detector and the amplitude modulator, wherein the feedback network is configured to generate the feedback-corrected control signal based on a difference between the amplitude feedback signal and an amplitude component (1006, 1106) of the original waveform. an IQ modulator configured to modulate an RF carrier signal based on a pair of IQ signals (908A,B) representative of at least the phase component of an original waveform to generate a phase-modulated RF signal (902, 1002, 1102); a fixed phase shifter (960, 1060) in communication with the IQ modulator and configured to generate a phase shift signal based on a phase characteristic of the phase-modulated RF signal (902, 1002, 1102); a feedback-controlled amplitude modulator (910, 1010, 1110) in communication with the IQ modulator and configured to modulate the phase-modulated RF signal (902, 1002, 1102) based on a feedback-corrected control signal to generate a modulated RF signal; a power amplifier (912, 1012, 1112) in communication with the amplitude modulator, wherein the power amplifier is configured to amplify the modulated RF signal and to generate an amplified RF output signal (904, 1004, 1104); an amplitude detector comprising an IQ demodulator (914, 1014) in communication with the power amplifier and the fixed phase shifter, wherein the fixed phase shifter is configured to receive the phase-modulated RF signal (902, 1002, 1102) from the IQ modulator and to synchronise a phase of the IQ modulator and a local oscillator of the IQ demodulator (914, 1014), and wherein the amplitude detector is configured to receive the phase shift signal, to detect an amplitude characteristic of the amplified RF output signal and to generate an amplitude feedback signal; and a feedback network (916, 1016, 1116) in communication with the amplitude detector and the amplitude modulator, wherein the feedback network is configured to generate the feedback-corrected control signal based on a difference between the amplitude feedback signal and an amplitude component (1006, 1106) of the original waveform.