Transmitter Apparatus

A transmitter apparatus ( 1 ) comprises a digital modulator ( 2 ), wherein the modulator is adapted to output a digital in-phase signal and a digital quadrature signal. The digital in-phase signal is converted to an analog in-phase signal and further processed in a path ( 31 ) for the in-phase signal, and a digital quadrature signal is converted in an analog quadrature signal and further processed in a path ( 34 ) for the quadrature signal. Thereby, an amplitude and delay mismatch in the path can occur. With the transmitter apparatus ( 1 ) of the invention the amplitude and delay mismatch can be measured. Further, an amplitude correction unit ( 43 ) is adapted for correcting the amplitude mismatch and a delay unit ( 3 ) is adapted to correct the delay mismatch. Further refinements of the amplitude and delay mismatch can be made with one or more predetermined test signals generated by a test signal generating unit ( 30 ).