Abstract: The invention introduces a coding unit for a high frequency power amplifier which encodes a useful signal into a binary signal so that a better energy conversion efficiency is achieved—even at an output power below the maximum output power of the high frequency power amplifier. The coding unit has a polar modulation unit, a pulse width modulation unit and a multiplier. Therein, the polar modulation unit has an input connected to an input of the coding unit and is designed to represent an input signal applied to the input of the coding unit as an envelope signal and a binary phasing signal. The pulse width modulation unit is connected to a first output of the polar modulation unit for the envelope signal and is designed to convert the envelope signal into a pulse-width modulated envelope signal and to output it to a first input of the multiplier.