The invention concerns a radio frequency transmitter (RFT) and a method of amplifying a radio frequency input signal (S.sub.IN) in the radio frequency transmitter (RFT). The radio frequency transmitter (RFT) comprises a digital signal generator (DSG) with a generation unit (GU) adapted to generate a pulsed bit stream signal and a switch mode power amplifier (SMPA) with a transistor circuit (PT) adapted to amplify the radio frequency input signal (S.sub.IN). The digital signal generator (DSG) further comprises a control unit (CU) adapted to detect in said pulsed bit stream signal a sequence of a constant signal height longer than a predefined threshold. The control unit (CU) is also adapted to initiate, upon detection of said sequence, a generation of a modified pulsed bit stream signal by an insertion of one or more notches in said sequence. Said notches interrupt said sequence by a signal of a signal height different from the signal height of the sequence. The radio frequency transmitter (RFT) further comprises connecting means (CM) adapted to provide said transistor circuit (PT) with said modified pulsed bit stream signal as the radio frequency input signal (S.sub.IN).