Determining a predistortion function includes sampling a signal to obtain a plurality of capture sets within a single sampling window. Each of the capture sets is analyzed to determine whether it satisfies preselected criteria. Example criteria include desired characteristics of a capture set average power, capture set peak power and a number of peaks within a capture set. If any capture set within the sampling window satisfies all of the preselected criteria and has the highest number of peaks, that capture set will be used for determining a predistortion function. A multiple capture set selection module applies the preselected criteria for selecting an appropriate capture set for determining the predistortion function. The predistortion function is used for applying predistortion to a signal before that signal is processed by a distorting component that introduces distortion so that the predistortion can compensate for or cancel out such distortion.