An apparatus for generating a radio frequency signal based on a symbol within a constellation diagram is provided. The constellation diagram is spanned by a first axis representing an in-phase component and an orthogonal second axis representing a quadrature component. The apparatus includes a processing unit configured to select one of a plurality of segments of the constellation diagram containing the symbol. The segment is delimited by two radially extending boundaries, wherein the two radially extending boundaries span an opening angle of the segment that is different from 90°. The processing unit is further configured to calculate a first coordinate of the symbol with respect to a third axis, and a second coordinate of the symbol with respect to a fourth axis. At least one of the third axis and the fourth axis coincides with one of the two radially extending boundaries. The apparatus further includes a plurality of digital-to-analog converter cells configured to generate the radio frequency signal using the first coordinate and the second coordinate.