Abstract-An alternative approach for assessing the conformity of electromagnetic interference measuring receivers with respect to the baseline CISPR 16-1-1 requirements is proposed. The method's core is based on the generation of digitally synthesized complex waveforms comprising multisine excitation signals and modulated pulses. The superposition of multiple narrowband reference signals populating the standard frequency bands allows for a single-stage evaluation of the receiver's voltage accuracy and frequency selectivity. Moreover, characterizing the response of the weighting detectors using modulated pulses is more repeatable and less restrictive than the conventional approach. This methodology significantly reduces the amount of time required to complete the verification of the receiver's baseline magnitudes, because time-domain measurements enable a broadband assessment while the typical calibration methodology follows the time-consuming narrow band frequency sweep scheme. Since the reference signals are generated using arbitrary waveform generators, they can be easily reproduced from a standard numerical vector. For different test receivers, the results of such assessment are presented in the 9 kHz-1 GHz frequency range. Finally, a discussion on the measurement uncertainty of this methodology for assessing measuring receivers is given.
This paper studies the advantages of applying timedomain based instrumentation to conduct electromagnetic interference emissions from rolling-stock. In IEC 62236-3-1 or EN 50121-3-1 standards, it is mandatory to measure the railway vehicle in static and in-motion conditions. When conventional frequency sweep instrumentation is employed, difficulties regarding ambient noise variation and the short-duration of worst-case emission modes take place. In Annex B of the standard, a test procedure is described to acquire the worst-case EMI, however, as it is explained at the paper the effective measured time at each frequency is only 0.08 ms in some frequency bands. Hence, multiple movements of the vehicle are needed increasing the uncertainty of the measured source and making difficult to distinguish vehicle EMI from background noise interference. To solve this problem, a Full-TDEMI measurement system is proposed with the availability to increase the effective measured time, reduced the ambient noise variation, the usage of multiple antennas at the same time and the possibility to discard transient interference that should not be evaluated. At the end of the paper, measurements carried out with the time-domain system are shown demonstrating the effectivity of the methodology.
A robust approach for estimating the expected maximum levels of radiofrequency, time-varying, electromagnetic emissions is proposed. The expected maximum peak value is intended to provide a statistical approximation for the worst case emissions scenario that accounts for the variability of the measured interference. The estimates are obtained through Monte Carlo resampling from a non-parametric distribution fitted by means of kernel density estimation applied to the time-frequency representation of the assessed interference. As a key advantage, calculating the expected maximum peak value does not require increasing the dwell time or holding the maximum value over successive sweeps. Results indicate the methodology is better suited than previous approaches for calculating the expected maximum peak value because it does not depend on normality assumptions difficult to guarantee in practice. The proposed technique is an example of how full time-domain EMI measurements can be exploited for obtaining further insights.
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