Abstract text

A solution is provided for correcting distortions on a radio frequency output signal of a power amplifier. There is provided an apparatus, comprising: a processor configured to determine at least one correction factor for a distortion on a radio frequency output signal of a power amplifier on the basis of estimated characteristics of a distorted time-varying supply voltage from a power supply to a power amplifier and an interface configured to feed the at least one correction factor to an input signal of the power amplifier.