The time-domain electromagnetic interference measurement system

TLDR

The study introduces a real‑time broadband TDEMI measurement system covering 30–1000 MHz. The system samples antenna signals, converts them via A/D, and applies digital processing including FFT, Welch, and Bartlett periodograms. Compared to existing EMI systems, the TDEMI system captures full phase and amplitude across the band, reduces measurement time by tenfold, and enables real‑time emulation of conventional detector modes and advanced analysis such as phase spectra and time‑frequency methods.

Abstract

A novel real-time broad-band time-domain electromagnetic interference (TDEMI) measurement system for the 30-1000-MHz frequency range is described. The signals from the antenna are sampled, analog-to-digital (A/D) converted and digitally processed. The fast-Fourier transform (FFT), the Welch- and Bartlett periodograms are digitally computed. Compared with state-of-the-art EMI measurement systems, the novel described TDEMI system samples the complete phase and amplitude information of the EMI simultaneously over the whole frequency band under consideration. With the presented time domain measurement system the measurement time can be reduced by a factor of 10. The digital processing of EMI measurements allows emulation in real-time of the various modes of conventional analogous equipment, e.g., peak, average, rms and quasi-peak detector and also introduces new concepts of analysis, e.g., phase spectra, short-time spectra, statistical evaluation and FFT-based time-frequency analysis methods.