A method for calibrating a radio frequency (RF) transmitter begins by mixing a modulated RF signal with an in-phase (I) component of a local oscillation or a quadrature (Q) component of the local oscillation to produce a baseband representation of the modulated RF signal. The method continues by converting the baseband representation of the modulated RF signal into a digital baseband signal. The method continues by filtering the digital baseband signal to produce at least one frequency spectrum component. The method continues by interpreting the at least one frequency spectrum component to produce a calibration signal. The method continues by calibrating at least one of DC offset and gain offset of digital transmitter processing module based on the calibration signal.