A. Gaggelli

Politecnico di Milano, Milano, Lombardy, Italy

Are you A. Gaggelli?

Claim your profile

Publications (4)2.65 Total impact

  • D. Bellan, A. Gaggelli, S.A. Pignari
    [Show abstract] [Hide abstract]
    ABSTRACT: This paper deals with three-axial systems for time-domain measurement of radiated emissions. A statistical analysis is developed in order to assess the influence of noise on the system measurement uncertainty in the case of nonstationary emissions, for which averaging techniques cannot be exploited. For a vector field with spatial components consisting of multiple sinusoids in additive white or colored noise, the modifications in the statistics of the measured signals due to application of the discrete Fourier transform to the digitized time series are investigated. The analysis is carried out in the frequency domain, and is used for probabilistic detection and maximum likelihood estimation of the amplitude of spectral lines close to the noise floor (i.e., in the typical conditions imposed by short-time measurement windows due to signal nonstationarity). Results are extended to sum, sum of squares, and logarithm of the amplitude of the spectral lines. As an application example, statistical estimates are derived for the safety factor used to assess compliance with the International Commission on Non-Ionizing Radiation Protection (ICNIRP) guidelines, in case of nonionizing radiation exposure to multiple frequency magnetic fields. The theoretical work is validated both versus test signals with known statistical properties and against measurement data obtained with a time-domain system for magnetic field measurement in the bandwidth 100 kHz-1.5 GHz.
    IEEE Transactions on Electromagnetic Compatibility 06/2009; · 1.33 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: This paper deals with the assessment of low-frequency magnetic-field emissions (MFE) in the engine-driver cab and the passengers' compartments of rolling stock. For emissions' measurement, an experimental setup is designed, involving a three-axial magnetic-field sensor mounted on an antenna positioner, and optically linked to the data-handling system. Measurement is accomplished in the time domain and allows one to retrieve digitized time series of the spatial components of the magnetic-flux density (MFD) vector, at specific points in the measurement volume. Worst case emissions are related to the train operating modes by referring to an experiment that includes acceleration from an initial stop, inertial motion, and braking up to a new stop. The nonstationary behavior of the most relevant MFD sinusoidal components is evidenced, and it is accounted in the spectral analysis by resorting to short-time Fourier transform based on a fixed-length time windows of proper duration. For safety assessment, a compliance check of MFE levels with exposure limits is proposed, based on the computation of an instantaneous safety parameter, obtained by extending requirements developed in the International Commission on Non-Ionizing Radiation Protection guidelines for the simpler case of multiple-frequency steady-state fields.
    IEEE Transactions on Electromagnetic Compatibility 03/2004; · 1.33 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: This article reports the statistical analysis of an experimental procedure to monitor magnetic flux density (MFD) emissions on board of rolling stock. Measurements are operated in the time-domain and are aimed to track possibly modulated sinusoidal components of MFD emissions. The impact of additive internal noise (generated by the measurement equipment) as well as external noise (due to nonsinusoidal sources) is investigated. Since the final goal is safety assessment, the transformations experienced by the experimental data are analyzed and the statistics of a safety parameter (reported in the ICNIRP guidelines) is derived in closed form. Specifically, the expected value and variance of such a parameter are obtained analytically. Results' validity is checked on test signals with known statistical properties, by a repeated-run analysis.
    Electromagnetic Compatibility, 2003 IEEE International Symposium on; 09/2003
  • Source