Provides a useful EVM troubleshooting decision tree.

Error vector magnitude (EVM) measurements can provide a great deal of insight into the performance of digitally modulated signals. With proper use, EVM and related measurements can pinpoint exactly the type of degradations present in a signal and can even help identify their sources. This note reviews the basics of EVM measurements on the Agilent Technologies 89400 vector signal analyzers, and outlines a general procedure that may be used to methodically track down even the most obscure signal problems.