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The paper presents a novel approach to relate the probability of malfunction of an EUT to the emission profile of the electromagnetic environment where the EUT is going to be installed. The proposed algorithm calculates the probability of malfunction at each frequency for both steady state signals and transient signals and then the overall probability of malfunction per number of frequencies.
Adaptive active filters can be successfully used to filter out interference on power and signal lines, where passive filters have great limitations especially if the interference is at low frequency and is known to drift slowly. Two solutions of adaptive filters are examined: the conventional LMS (Least Mean Square) filter and the LMS filter with trainer units, which have the best filtering characteristics...
Large amount of data are obtained from simulation or experimental activities. In most cases they are not of easy interpretation; factor analysis provides a tool to highlight those situations of major interest in EMC related to interaction mechanisms between electrical, geometrical and mechanical parameters. The case of field to cable coupling, a typical immunity problem, is presented to illustrate...
To shield low-frequency magnetic field is necessary to surrounding the entire volume of interest with ferromagnetic metal barriers. However it is as much known that a good ferromagnetic material is more expensive especially with high permeability ferromagnetic material and also is very heavy. An adequate and cheaper possibility is the use of a multilayer screens. In this paper, we have investigated...
In EMC testing of medical devices the risk assessment is a subject of great importance and is a rather new topic. Unfortunately no much experience exists on this subject. This paper presents an approach which has been used in the risk assessment of IVD (In Vitro Diagnostic) medical devices. We show how the risk can be assessed in a probabilistic manner proposing a procedure applicable to both steady...
In the fields of electromagnetic interference and electromagnetic compatibility, it is important to measure the strength of the electric field originating from electric devices. For this purpose, knowledge of the antenna factor of a receiving antenna is necessary. In this paper, we discuss the recently measurement methods called Antenna Impedance Method as a new calibration method able to obtain the...
This paper presents the approach proposed to determine the uncertainty of immunity tests when the Equipment under Test (EUT) is susceptible and when it is not. An important issue of immunity testing is the Susceptibility Threshold, which represents the boundary between the susceptibility and the immunity regions of an EUT.
This paper provides a novel policy for EMC antenna calibration in order to establish when antennas must be calibrated on the basis of their actual degraded conditions. The proposed policy is to measure the reflection coefficient at the antenna terminal and to compare it to a reference standard of the same antenna when properly calibrated.
A typical electromagnetic (EMC) issue is the determination of the electromagnetic fields inside an enclosure with thin aperture. The solution times of Intermediate Level Circuit Model (ILCM) are three orders of magnitude less than the traditional numerical techniques. The Logistic Regression (LR) algorithm is used to analyze the outputs of the simulation runs. This regression model allows to highlight...
Adaptive active filters can be successfully used to filter out interference on power and signal lines, where passive filters have great limitations especially if interference is at low frequency and is known to drift slowly. Three possible solutions of adaptive filters are examined. Conventional LMS filters generate intermodulation products, which in some cases are not acceptable. The novel solution...
The idea proposed in this paper is to relate susceptibility uncertainty to the cause generating it, which corresponds to the conducted or radiated signal injected into the equipment under test (EUT). But even with this simplification there are still problems mainly due to the need to perform repetitive tests, which are not compatible with the cost implications involved. Simulation tools using Monte...
The distribution and interleaving of signals represents a simple method, which can be used successfully for general purpose filtering. Presently it is commonly utilized in switched mode power converters. The mathematical formulation of the method is presented and widened to cover more general situations; moreover with the help of a system simulator the cases of low pass and band pass filters are studied...
In this paper the ISO/IEC 17025 accreditation requirements relevant to radiated emission tests performed according to parts 2 and 3.1 of norms EN 50121 and IEC 62236 are discussed. This is particularly difficult due to the unconventional nature of test environment, not only because tests are performed outdoors but mainly because radiated emissions from system under test shall be measured while it...
The need of performing immunity tests with the aim of meeting the functional safety requirements is addressed proposing an approach based upon the statistical data processing of test results, which allows to determine the susceptibility threshold of the device under test (DUT) and its safety margin intended as the distance between the actual DUT performance in the presence of the susceptibility signal...
Multiple linear regression can be successfully used to detect the shielding effectiveness (SE) degradation of enclosures by comparing the results of tests performed at regular time intervals. Simulations are performed on a rectangular metal enclosure with rectangular and circular apertures of various sizes. The frequency curves of the voltages picked by sensors located inside shielded enclosures are...
The uncertainty evaluation in the calibration of two-port networks transmission coefficient is here dealt with Attention is focused on the covariance contribution of the uncertainty expression and on the effect of mismatch terms. To this aim, the approach suggested by the Guide for the expression of uncertainty in measurement (GUM) is discussed, and solutions are proposed aimed at optimally combining...
Logistic Regression, a statistical analysis tool used for epidemiological studies, can be successfully exploited to interpret susceptibility test results with the twofold aim of understanding which are the most significant causes affecting the Device under Test (DUT) and of providing a technique to define a global figure of safety margin when many test parameters are involved. The background of Logistic...
The use of the computer to obtain an Emission Measurement Automatic System (EMAS) is described. Major advantages are increased measurement accuracy and reduction of testing time and effort. Frequency accuracy better than 0.1 percent and amplitude accuracy (assuming an ideal calibrator) better than 0.5 dB have been demonstrated. The computer is used both for controlling the test execution and for off-line...
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