3. Non-linear distortions

We're only interested in the first category here. The linearity of a system is its ability to deliver a signal that is homothetic at all points to the input signal, and although not all RF power applications require the same quality with regard to this criterion, a good understanding of its aspects is necessary for the implementation of RF power circuits. After a brief description of the linearity issue, this section looks at the problems of definition and characterization, and reviews a number of linearization processes, some of which are applicable to amplifiers alone, others to the complete system.