Understanding EVM

White Paper Overview 

The need for greater data throughput influences either increased bandwidth and/or higher modulation orders. Higher order modulation requires higher modulation accuracy, therefore quantifying modulation accuracy is critical in the design, test, and debugging of modern radio frequency communications technologies.

This paper provides an introduction to error vector magnitude (EVM); the primary metric of modulation accuracy. It discusses the fundamentals of the digital modulation schemes used in modern radio frequency communications systems, in particular, APSK and QAM, the fundamentals of error vector magnitude, and basics of constellation diagrams including diagnosis and troubleshooting common root causes of EVM.