A novel time-domain EMI Measurement System for Measurement and Evaluation of Discontinuous Disturbance according to CISPR 14 and CISPR 16

Measurement of electromagnetic interference has been performed in the past by EMI receivers operating in frequency domain. For the measurement of discontinuous disturbance for IT and Household appliances EMI receivers are used to tune to a specific frequency. The output of the Intermediate Frequency is connected to a disturbance analyzer. The measurement is repeated at four frequencies. Due to the limited dynamic range of the IF-Output in many cases the measurement has to be repeated with a higher attenuator setting. Such disturbance analysis can take up to 16 hours for the measurement of one device under test. Measurements of electromagnetic interference in time-domain allow to reduce the scan time, in comparison to automated scans performed by the tuned selective voltmeters, which are known as EMI receivers. By real-time implementation of several thousand Quasi-Peak Detectors on the field programmable gate arrays (FPGA) and real-time evaluation of the virtual IF-Signal at several frequencies calculated at the same time scan time is reduced. In this paper a time-domain EMI measurement system covering the frequency range 9 kHz - 18 GHz is presented that allows to measure emissions according to CISPR 16-1-1, and perform the discontinuous disturbance analysis as described by CISPR 16-1-1, CISPR 14-1 and CISPR 22. Measurements on household appliance are shown.