Digital Predistortion for Improved EVM Performance

This document provides a comprehensive guide on how signal and spectrum analyzers can be used to create a Hammerstein model for the vector signal generator's output stage, and subsequently addresses the inherent non-linearities characteristics.

DPD Fundamentals and Linearizing RF Output Stages

Direct DPD vs. Hammerstein Model Approach

Step-by-Step Hammerstein Model Workflow

Applying/Handling Model Files on the SMW

EVM Evaluation and Example Use Cases

Application Note

Inherent non-linearities in a PA impacts the signal quality when operated at elevated power levels. DPD technique addresses these limitations by pre-distorting the signal with the inverse PA characteristic before feeding it to the PA. The cascade of the PA and the DPD leads to a linear characteristic. This method is used in most state-of-the-art cellular, non-cellular or satellite communication devices. As the architecture of the RF chain of a signal generator is similar, it may also be used to improve the performance of a signal generator’s output stage. This article provides practical examples of R&S solution to accomplish this.