A polar modulation transmitter offers a split architecture for determining amplitude modulation path delay of the transmitter and comprises a split supply modulation circuit and a split power amplifier circuit. The split supply modulation circuit includes a common supply input and is configured to receive a common amplitude-modulation signal at respective signal inputs and output first and second modulated supply signals responsive to the common amplitude-modulation signal. The split power amplifier circuit includes first and second supply inputs each coupled to one of the respective modulated supply signals, first and second signal inputs and first and second outputs each responsive to the respective supply and signal inputs, the split power amplifier circuit being configured to receive a common phase-modulation signal at its signal inputs and combine its outputs to form a signal having amplitude modulations responsive to the common amplitude-modulation signal and phase modulations responsive to the common phase-modulation signal.