A Time-Domain system for EMI measurements above 1 GHz with high sensitivity

In this work, a broadband Time-Domain EMI Measurement System with high sensitivity for measurements from 9 kHz to 18 GHz is presented. Combining ultra-fast analog-to-digital-conversion and real-time digital signal processing on a field-programmable-gate-array (FPGA) with ultra-broadband multi-stage down-conversion, scan times can be reduced by several orders of magnitude in comparison to a traditional heterodyne EMI Receiver. The system´s ultra-low noise figure of 6-8 dB over the complete frequency range allows for broadband measurements with highest sensitivity of EMI near the noisefloor up to 18 GHz. The time-behaviour of non-stationary EMI can be evaluated via the real-time Spectrogram.