Why Visual Spectra Lie in Noisy Environments
Introduction Engineers rely heavily on spectral plots to diagnose signals. Yet many DSP failures begin with trusting what “looks obvious” in frequency graphs. In noisy environments, visual spectra frequently misrepresent reality. This article explains why human interpretation of spectral plots is unreliable under noise and how estimator behavior distorts perception. The Illusion of Smoothness Spectra appear smooth due to: window averaging visual scaling plotting interpolation But underlying estimates still contain large statistical variance. ...