In this paper, an advanced ultra-fast, broadband time domain EMI measurement system is described. Measurements were performed in the 30–1000MHz range. The digital signal processing of EMI measurements allows to emulate in real-time the modes of conventional analogous equipment, e.g. Peak-, Average-, RMS- and Quasi-Peak- Detector. With the presented time domain measurement system the measurement time can be reduced by a factor of 10. A novel signal recording routine for time-domain EMI (TDEMI) measurements and Quasi-Peak-Detection is described. Measurement results obtained from the investigation of a drillmachine, monitor and laptop obtained with the timedomain electromagnetic interference (TDEMI) measurement system are discussed. The results obtained with the described system have been compared with measurements performed with a conventional EMI receiver.