A predistortion actuator is provided. The predistortion actuator includes a plurality of branches, each of which implements a basis function that acts on a digital input signal. For at least one of the branches, the respective basis function is a sectioned basis function, where each section of the sectioned basis function corresponds to a respective section of a range of at least one input signal characteristic associated with the digital input signal, such as a value range of a magnitude, a temporal characteristic, or a hybrid of the two. A power amplifier system including the predistortion actuator is also provided. Utilizing sectioned basis functions can potentially reduce the hardware resources necessary to realize the predistortion actuator relative to conventional global basis functions. In addition, signal conditioning during coefficient training can potentially be used to reduce the dynamic range of coefficients associated with each sectioned basis function.