The present invention provides an electronic circuit for measuring of an output power of a RF power amplifier. The electronic circuit comprises a current sensing transistor for sensing the RF current of the power amplifier and a voltage sensing module for sensing the voltage of the RF power amplifier. The electronic circuit further comprises a coherent detector for multiplying the sensed current and the sensed voltage in the time domain. In this way a signal is generated that is directly indicative of the power provided by the power amplifier irrespective of its actual load. Preferably, the coherent detector is implemented as a Gilbert quad and provides a differential output that effectively allows for DC offset compensation.