Measuring with Modern Spectrum Analyzers

This application note examines both the theory and practice of state-of-the-art spectrum analysis by discussing specific measurements taken on an integrated RF amplifier. The theoretical portion of this document first describes how modern spectrum analyzers are designed and how they work. That is followed by a brief characterization of today's signal generators, which are needed as a stimulus when performing amplifier measurements. The effects on the spectrum that are caused by the nonlinearity of real devices under test are derived mathematically. The practical portion of this application note contains detailed test and measurement tasks that are suitable for use as lab exercises performed in small groups. The purpose of these tasks is to illustrate the explanations provided in the theoretical section and to provide a deeper understanding of the principles explained there.