Error Vector Magnitude: The Heart of Everything Wireless
Application Notes
Want to achieve greater data capacity? Optimize signal-to-noise ratio (SNR).
Want to increase power efficiency? Improve your digital predistortion algorithm.
Want to increase your communication signal’s power? Minimize the wideband distortion.
How are all these connected? Error vector magnitude, or EVM.
To optimize SNR, first look in-band. By definition, EVM is the measure of in-band SNR. Improving your digital predistortion algorithm improves signal linearity, which in turn improves EVM. At the core of characterizing and minimizing wideband distortion is a traditionally challenging and expensive residual EVM measurement.
It’s unavoidable. EVM crosses all paths in the pursuit of more data, higher power, and greater efficiency. And its implications are greater today than ever before.
This application note looks at three key places where EVM intersects with radiofrequency (RF) engineers’ design goals for transceivers and power amplifiers in wireless and satellite communications industries: achieving greater data capacity, increasing power efficiency, and increasing wideband signal power. Additionally, we offer recommendations for test hardware and software designed to meet the respective design goals.
We begin with a brief overview of EVM.