The present invention relates to pre-distortion in transmitter circuits and provides a circuit for introducing pre-distortion into the output of a transmitter, wherein said pre-distortion comprises a pre-cursor, a cursor and a post-cursor, the circuit comprising: a first driver arranged to switch an output drive between said pre-cursor and said cursor; a second driver arranged to switch an output drive between said post-cursor and said cursor; a third driver arranged to switch an output drive between a positive cursor drive and a negative cursor drive. The arrangement provided give flexibility when setting the pre-cursor, cursor and post-cursor levels.