A base band to frequency up-converter is described wherein the base band to frequency up-converter comprises a first input for receiving a first base band signal of first base band samples and a second input for receiving a second base band signal of second base band samples and an output for providing up-converted radio signal samples. The base-band to radio frequency up-converter further comprises a phase converter for converting the first base band signal of first base band samples and the second base band signal of second base band samples into a first intermediate signal of first intermediate samples, a second intermediate signal of second intermediate samples, and a third intermediate signal of third intermediate samples. The intermediate samples are then up-converted into radio signal samples.