Abstract: This specification relates to an apparatus which stores a machine-learned model including a first neural network block including multiple convolutional neural network layers, a second neural network block including at least one dilated convolutional neural network layer, and a linear transformation block. The apparatus is configured to receive input data representing in-phase and quadrature signals of an input signal that is to be amplified by a power amplifier, to process the received input data using the first neural network block of the machine learned model to generate a first neural network block output, to process the received input data using the second neural network block of the machine learned model to generate a second neural network block output, and to combine, using the linear transformation block, the first neural network block output and the second neural network block output to generate a pre-distorted signal for amplification by the power amplifier.