Verification of frequency analysis experimental setup

In a variety of engineering tasks, accurate measurement of signal spectrum presents necessary requirement. Hardware bring-up with noise sources tracing, through DC power sources validation and profiling, AD and DA signal conversion, communication channels verification, mutual units influence checks and many other applications lean on frequency analysis results. In many real life scenarios engineers take frequency spectrum results from the measurement units as is, without deeper investigation abut measurement uncertainty, especially related to ratio between signal period and windowing function length which could introduce significant differences. Aim of this paper is to highlight two things, first is advantage of automated custom tailored test setup, which decreases probability of gross errors and second is error validation of the harmonic content of complex periodical signals. Digital high-end oscilloscope with embedded FFT function including several windowing functions is used as test unit in automation process and also for the measurement error investigation.