Dynamic Performance Evaluation of Full Time Domain EMI Measurement Systems

This paper presents the evaluation of the performance of Full Time Domain Electromagnetic Interference measurement systems in terms of the noise figure, the linearity, the dynamic range, the voltage standing wave ratio and the crosstalk. The abovementioned parameters allow a broader characterization of the oscilloscope-based implementations of CISPR 16-1-1 measuring receivers, providing relevant specifications that are beyond the standardized baseline requirements. Such metrics are assessed using the actual settings and operating conditions required for compliant time-domain EMI measurements. For the specific oscilloscope used in the experiments, the noise figure is measured for all the different vertical ranges between 5 mV/div and 1 V/div. Likewise, the linearity and the dynamic range, in terms of the effective number of bits, was measured for sine wave input signals with an rms voltage swept between 20 mV and 1 V. This experiment was repeated for CISPR bands A, B and C/D using 10 kHz, 1 MHz, and 100 MHz sinusoids, respectively. The results allow a more comprehensive comparison between Full-TDEMI measurement systems and the more conventional superheterodyne architecture receivers that are completely specified in the frequency domain.