In this paper, a quasi-peak detector mode for a time-domain electromagnetic interference (TDEMI) measurement system is described. Measurements were performed in the 30-1000-MHz range. The digital signal processing of EMI measurements can emulate in real time the modes of conventional analog 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 ten. A novel signal recording routine for TDEMI measurements and quasi-peak detection is described. Measurement results obtained from the investigation of a drill machine, monitor, and laptop obtained with the TDEMI measurement system are discussed. The comparison of the results obtained with the described TDEMI measurement system and measurements performed with a conventional EMI receiver show an average deviation over the whole frequency range less than 3 dB.

Quasi-peak detector model for a time-domain measurement system

A low-cost electromagnetic compatibility precompliance test-set is essential to reduce the development costs of any electrical device. In this paper we discuss the advantages of broadband time-domain preliminary compliance measurement techniques applied to all types of electromagnetic interferences. The digital signal processing of electromagnetic interference measurements allows emulating in real-time the various modes of conventional analogous equipment, e.g., peak, average, root mean square, and quasi-peak detector mode. Since time-domain techniques allow processing the whole amplitude spectrum in parallel, the measurement time may be reduced by at least one order of magnitude. Compliance measurement results for conducted and radiated emissions obtained with the time-domain electromagnetic interference (TDEMI) system are shown. The TDEMI system has a real-time bandwidth of 1.5 GHz. Measurement techniques for nonstationary signals and single events are discussed.

Signal processing strategies with the tdemi measurement system

Electromagnetic Compatibility or EMC is the ability for the product or equipment
under test (EUT) able to operate in its intended environment with causing undue
interference or being unduly affected by it. The requirement for non-interference has
been known for many years but it is only now with the introduction of legislation that
we are seeing a major growth in demand for testing. The USA with its FCC regulations
has for some time tried to control emissions from certain types of equipment. Japan
has also had a voluntary code (VCCI) and Europe, after some delay, fully introduced
mandatory regulations at the end of 1996.
The ultimate importance of an EMC testing is to ensure the EUT is not affected
by the other operating EUT and vice versa. These conditions apply for both conducted
(CE) and radiated emission (RE). Other areas are now introducing regulations and it
seems likely that the system will spread to encompass the whole world in the future.
Currently, measurement of an equipment under test (EUT) shall cast a doubt when the
result is close to the specification limits. In the common practice, the MU is taken as
an informational purpose only in the report and not for the EUT status. The
implementation of the measurement uncertainty for the reporting is crucial since the
EUT might fail the EMC test if the passing margin is below the International Special
Committee on Radio Interference (CISPR) standards.
In acquiring the MU for the judgement criteria, comparison with the standards
and inter-laboratory comparison shall take place. These include the standard
classification for the EUT type, expanded uncertainty estimation to the CISPR
standard (UCISPR), EMC equipment factor estimation and proficiency test with the other
accredited EMC laboratory using the Z-Score method. The inter-laboratory
comparison used the same calibrated signal source which emits the stable broadband
emission. Finally, the cumulative results are to be taken as a laboratory expanded uncertainty ULAB= 2uc(y). The thesis focused the application of the expanded
uncertainty deployment for the judgement criteria for the finalize EUT status.

Characterization of the measurement uncertainty for the electromagnetic conducted and radiated emission test

Based on the operating principle of a typical electromagnetic interference test receiver and the circuits of various commonly used detectors, a simulation model is developed. With the model, the response of each detector to broadband emission can be simulated and analyzed. The conversion factors between different types of detectors for the same type of broadband emission are determined and verified with those reported in well establish standards. The systematic analysis provides both insight and rationale behind how these conversion factors are derived.

Conversion Factors Between Common Detectors in EMI Measurement for Impulse and Gaussian Noises

The upgrade of the Large Hadron Collider (LHC) experiments at CERN sets new challenges for the powering of the detectors. One of the powering schemes under study is based on DC-DC buck converters mounted on the front-end modules. The hard environmental conditions impose strict restrictions to the converters in terms of low volume, radiation and magnetic field tolerance. Furthermore, the noise emission of the switching converters must not affect the performance of the powered systems. A study of the sources and paths of noise of a synchronous buck converter has been made for identifying the critical parameters to reduce their emissions. As proof of principle, a converter was designed following the PCB layout considerations proposed and then used for powering a silicon strip module prototype for the ATLAS upgrade, in order to evaluate their compatibility.

Optimization of the design of DC-DC converters for improving the electromagnetic compatibility with the Front-End electronic for the super Large Hadron Collider Trackers

The objective of electromagnetic interference (EMI) measurements is to determine if the emitted electromagnetic energy is low enough to fulfil the desired electromagnetic compatibility. Standards for EMI define maximum limits for the emission of interfering radio frequency (RFI) energy. The purpose of EMI measurements is, in most cases, to find out, whether or not the equipment under test (EUT) meets the limits. Two different principles to reduce time consumption of quasi-peak (QP) EMI measurements are explained. The two may be combined to minimize the test time. >

K.-O. Muller

Papers

Speeding up quasi peak weighting EMI tests