Circuitry, method and computer program for reducing distortions in a plurality of amplified signals to be radiated by a multiple antenna system. The circuitry comprising: a plurality of inputs for receiving digital signals for a plurality of forward data paths; routing circuitry for routing the digital signals received at the plurality of inputs to pre-distortion logic for applying a pre-distortion function to each of the signals, the pre-distortion logic being operable to forward each of the signals towards a digital to radio frequency converter and subsequent amplifier for amplifying the signals prior to the signals being radiated; one or more feedback paths each comprising processing logic for comparing a feedback signal generated from one of the amplified signals with a corresponding signal received at one of the inputs to determine a function to be applied by the pre-distortion logic to the input signal; selecting logic for selecting the input signal to be provided with the feedback.