Transmission/reception device for a mobile radio, having - a polar modulator that is based on the processing of a digital complex baseband signal (x(k)) in the form of a digital magnitude signal (r(k)) and a digital phase signal (φ(k)) and that comprises -- a first amplifier for amplifying a radio-frequency signal (y'(t)) that is dependent on the digital phase signal (φ(k)) and the output power of which can be modulated on the basis of the digital magnitude signal (r(k)), and -- at least one predistorter (11, 12), connected upstream of the first amplifier in the signal direction, for at least partially compensating for distortion brought about by the first amplifier using adjustable predistortion, - a second amplifier that is connected downstream of the first amplifier, - a reception path that is used both -- for receiving radio signals and -- for adjusting the at least one predistorter (11, 12) to ascertain a measurement signal that is dependent on the output signal (s(t)) from the first amplifier, - a coupling path for electrically coupling the input of the reception path to the output of the first amplifier, wherein the second amplifier is deactivated for adjusting the at least one predistorter (11, 12), and - a control and evaluation means (34, 36) for adjusting the at least one predistorter (11, 12) on the basis of the measurement signal. - a polar modulator that is based on the processing of a digital complex baseband signal (x(k)) in the form of a digital magnitude signal (r(k)) and a digital phase signal (φ(k)) and that comprises -- a first amplifier for amplifying a radio-frequency signal (y'(t)) that is dependent on the digital phase signal (φ(k)) and the output power of which can be modulated on the basis of the digital magnitude signal (r(k)), and -- at least one predistorter (11, 12), connected upstream of the first amplifier in the signal direction, for at least partially compensating for distortion brought about by the first amplifier using adjustable predistortion, -- a first amplifier for amplifying a radio-frequency signal (y'(t)) that is dependent on the digital phase signal (φ(k)) and the output power of which can be modulated on the basis of the digital magnitude signal (r(k)), and -- at least one predistorter (11, 12), connected upstream of the first amplifier in the signal direction, for at least partially compensating for distortion brought about by the first amplifier using adjustable predistortion, - a second amplifier that is connected downstream of the first amplifier, - a reception path that is used both -- for receiving radio signals and -- for adjusting the at least one predistorter (11, 12) to ascertain a measurement signal that is dependent on the output signal (s(t)) from the first amplifier, -- for receiving radio signals and -- for adjusting the at least one predistorter (11, 12) to ascertain a measurement signal that is dependent on the output signal (s(t)) from the first amplifier, - a coupling path for electrically coupling the input of the reception path to the output of the first amplifier, wherein the second amplifier is deactivated for adjusting the at least one predistorter (11, 12), and - a control and evaluation means (34, 36) for adjusting the at least one predistorter (11, 12) on the basis of the measurement signal.