Pre-distorter and corresponding method for deriving same

Abstract

A method of deriving a pre-distorter for a corresponding non-linear amplifier is disclosed. The first step of the method is to form the pre-distorter's topology. This is done by first determining a corresponding inverse topology to the non-linear amplifier's topology. The non-linear amplifier has a topology comprising filter and non-linear amplifier elements. The inverse topology comprises corresponding inverse filter and amplifier elements to the amplifier's filter and non-linear amplifier elements. Then, those of the inverse filter and amplifier elements for which compensation with the pre-distorter is desired are selected. Any of the inverse filter and amplifier elements that were not selected are then removed from the inverse topology to form the pre-distorter's topology. Thus, the pre-distorter's topology comprises the selected inverse filter and amplifier elements. After the pre-distorter's topology is determined, a predefined input signal is applied to the non-linear amplifier. In response, measurements of selected signals of the non-linear amplifier are made. Once the measurements are made, coefficients that define the selected inverse filter and amplifier elements' are estimated. This is done in response to the measurements that were made.