Redefinition of the Amplitude Probability Distribution Measuring Function for Electromagnetic Emissions Assessment

The amplitude probability distribution (APD) is a measuring function for assessing electromagnetic disturbances, especially those with a stochastic and time-varying distribution. According to the CISPR 16-1-1, the APD has been defined as the cumulative distribution of the probability of time that the amplitude of disturbance exceeds a specified level. The APD is highly correlated to the bit error rate of digital communication systems, and therefore, a redefinition of radiated emission limits based on the APD would be very meaningful in terms of protecting wireless systems from unintentional interferences. However, establishing emissions requirements based on the current standard APD method can be misleading and not completely traceable metrology-wise. This is because, when analyzing electromagnetic compatibility (EMC) standards, the current specifications for APD measurements are unclear and ill-posed. For instance, the APD is only defined for applications above 1 GHz and with a fixed resolution bandwidth of 1 MHz; both conditions are arbitrarily set due to legacy considerations. Given the capabilities and flexibility of available instrumentation technology, we will propose an improved and more general APD definition accompanied by a calculation algorithm. Moreover, we argue that the APD measurements shall move from a histogram-based approach and implement kernel density estimation instead. We deliver evidence that exemplifies and supports our revised APD definition through numerical simulations. The study closes with a critical discussion about why the APD is so relevant and how it can be redefined to become widely employed as part of EMC assessments.The project (21NRM06 EMC-STD) has received funding from the European Partnership on Metrology, co-financed by the European Union's Horizon Europe Research and Innovation Programme and by the Participating States. EMC Barcelona's project under grant number SNEO-20211223 has received funding from CDTI, which is supported by "Ministerio de Ciencia e Innovación" and financed by the European Union - NextGenerationEU - through the guidelines included in the `Plan de Recuperación, Transformación y Resiliencia". Dr. Azpúrua has received funding from the StandICT.eu 2023 project, financed by the European Union's Horizon Europe - Research and Innovation Programme - under grant agreement No. 951972

Conducted Emissions Verification Setup Improvement for Space Applications

Just-before-test verification is needed to ensure that electromagnetic interference measurements are correctly performed. Some standards cover such specific requirements regarding test verification, this is the case of the ECSS-E-ST-20-07c for space applications. However, some drawbacks in the standard procedure have been identified, and in this work, we provide advice for improving the conducted emissions verification. For instance, we argue that the complete frequency range of the test should be evaluated during the verification of the test equipment, not just two single frequencies. Likewise, it is demonstrated how the standard verification setup introduces a significant mismatch that can compromise the accuracy of the result. Moreover, this work highlights the capabilities of novel instrumentation like high-end oscilloscopes that effectively provide convenient alternatives to improve further and simplify the measurement methodology while achieving even more accurate results if applied correctly.This work was supported in part by the European Union's Horizon 2020 research and innovation programme under Marie Skłodowska-Curie grant agreement No. 801342 (TecniospringINDUSTRY) and the Government of Catalonia's Agency for Business Competitiveness (ACCIÓ) and in part by the Spanish "Ministerio de Ciencia e Innovación" under project PID2019- 106120RBC31/AEI/10.13039/501100011033. EMC Barcelona's project under grant number SNEO-20211223 has received funding from CDTI, which is supported by "Ministerio de Ciencia e Innovación" and financed by the European Union – NextGenerationEU – through the guidelines included in the "Plan de Recuperación, Transformación y Resiliencia." Dr. Azpúrua has received funding from the StandICT.eu 2023 project, financed by the European Union's Horizon Europe - Research and Innovation Programme - under grant agreement no. 951972

Strategies Using Time-Domain Measurements for Radiated Emissions Testing in Harsh Environments

Performing in-situ radiated emissions measurements, that is, in locations different from a standard test site, can be a challenging task because of the high electromagnetic noise levels in the ambient. A harsh electromagnetic environment characterizes such sites, and it usually results in difficulties when discerning between emissions from the equipment under test (EUT) and electromagnetic fields generated by surrounding devices. Moreover, communication signals from broadcasting services are generally significantly higher than the standard emission limits, making it even harder to determine compliance. In this article, we present different techniques leveraging the advantages of time-domain measurement systems to provide effective and practical solutions to mitigate ambient noise’s effect on radiated electromagnetic interference measurements. First, the test method used is described, and pragmatic considerations are given to ensure reliable and repeatable measurements. Multichannel time-domain measurement systems are introduced as the fundamental tool for the proposed strategies. Subsequently, different study cases are evaluated with real test examples, highlighting several criteria intended to reduce the impact of ambient noise on the actual emissions measures produced by the EUT. Finally, a real application of those strategies for measuring a photovoltaic system is described. Overall, the methods employed and the main advantages of using full-time-domain FFT-based receivers are reviewed. In addition, the possibility of incorporating this article’s outcomes into forthcoming electromagnetic standards about in-situ radiated emission measurements is also debated.This work was supported in part by the European Partnership on Metrology, co-financed by the European Union's Horizon Europe Research and Innovation Programme and by the Participating States under Project 21NRM06 EMC-STD, and in part by the "Ministerio de Ciencia e Innovación" through the Project DIN2021-012003 under Grant MCIN/AEI/10.13039/501100011033 and Grant PID2019-106120RBC31/AEI/10.13039/501100011033. EMC Barcelona was supported by the "Ministerio de Ciencia e Innovación" and financed by the European Union—NextGenerationEU, which has received funding from CDTI through the guidelines included in the "Plan de Recuperación, Transformación y Resiliencia" under Grant SNEO-20211223. Dr. Azpúrua works as a standardization expert of the StandICT.eu 2023 Project, which was financed by the European Union's Horizon Europe—Research and Innovation Programme—under Agreement 951972

Measuring Receiver Benchmark for Conducted and Radiated Emissions Testing in Space Applications

This paper compares the measurement results obtained from three different implementations of measuring receivers regarding spectral level accuracy. The objective is to validate the suitability of direct sampling electromagnetic emissions measurements with respect to those delivered by a high-end EMI receiver in frequency swept and FFT modes. The experimental setups follow the verification methods described in the ECSS-E-ST-20-07C Rev.2 standard to set realistic and reproducible conditions. Between 50 kHz and 100 MHz, common mode and differential mode currents are measured when multisine excitation signals with controlled amplitude profiles are used as references. Subsequently, conducted and radiated emissions tests are run to investigate the correlation between measurements with the different receivers. The instruments used are a low-cost USB digitiser Picoscope PS5444D, a high-performance benchtop oscilloscope R&S RTO6 and the R&S ESW44 full-compliant EMI test receiver. The analysis concludes that the emissions measurements performed with the direct sampling approach are excellent for the intended application, exhibiting an accuracy comparable to the dedicated EMI test receiver and a well adequate dynamic range and noise level.The project (21NRM06 EMC-STD) has received funding from the European Partnership on Metrology, co-financed by the European Union's Horizon Europe Research and Innovation Programme and by the Participating States. EMC Barcelona's project under grant number SNEO-20211223 has received funding from CDTI, which is supported by "Ministerio de Ciencia e Innovación" and financed by the European Union - NextGenerationEU - through the guidelines included in the `Plan de Recuperación, Transformación y Resiliencia". Dr. Azpúrua has received funding from the StandICT.eu 2023 project, financed by the European Union's Horizon Europe - Research and Innovation Programme - under grant agreement No. 951972. Dr. Pous' work was supported in part by the European Union's Horizon 2020 research and innovation programme under Marie Skłodowska-Curie grant agreement No. 801342 (TecniospringINDUSTRY) and the Government of Catalonia's Agency for Business Competitiveness (ACCIÓ) and in part by the Spanish "Ministerio de Ciencia e Innovaci´on" under project PID2019-106120RBC31/AEI/10.13039/501100011033

Time-Domain Electromagnetic Characterization of Reaction Wheel for Space Applications

The electromagnetic characterization of reaction wheels is crucial to comply with the demanding ac magnetic field cleanliness requirements of space science missions, thus, preventing interference on sensitive onboard instrumentation. Therefore, a complete assessment, including the measurement of the magnetic flux vector at different operational modes and under dynamic conditions, is proposed as a contribution beyond conventional testing methodologies. This article investigates the worst-case magnetic field emissions experimentally, using a test setup based on a multichannel acquisition and multidomain postprocessing system. The focus of the measurement campaign was on the low-frequency range (10 Hz–2 kHz). Moreover, capturing the B-field in the time-domain enabled further analysis, that is, complementary outputs for understanding the electromagnetic performance of the reaction wheel. As a result, we can relate the wheel rotation with the current and the magnetic fields, compute the field orientation, and evaluate in-band interference for the magnetic field.This work was supported in part by European Union's Horizon 2020 research and innovation programme under Marie Skłodowska-Curie under Grant Agreement 801342 (TecniospringINDUSTRY) and the Government of Catalonia's Agency for Business Competitiveness (ACCIÓ) and in part by the Spanish "Ministerio de Ciencia e Innovación" under Project PID2019-106120RBC31/AEI/10.13039/501100011033. EMC Barcelona's project under grant number SNEO-20211223 has received funding from CDTI, which is supported by "Ministerio de Ciencia e Innovación" and financed by the European Union – NextGenerationEU – through the guidelines included in the "Plan de Recuperación, Transformación y Resiliencia.

Efficient In situ Assessment of Radiated Emissions using Time-Domain Measurements

This paper presents three different case studies where the electromagnetic emissions of atypical equipment (a photovoltaic system, a passenger boarding bridge and a pallet washing machine) have been assessed in situ using time-domain measurement systems. The magnetic field (150 kHz-30 MHz) and electric field (30 MHz-1 GHz) emissions are considered. The technical challenges encountered and the solutions adopted for each scenario will be highlighted by describing the methodology employed. The goal is to relate the empirical knowledge and know-how gained through those study cases with the specific requirements and procedures defined in the standards. In that sense, multi-channel time-domain emissions measurements have been essential to carry out those measurement campaigns efficiently. The results are summarised as lessons learned during the experiences reported in this article. This work is relevant to support the revision or development of standards about in situ EMC testing as it provides helpful evidence to validate alternative radiated emissions measurement methods under realistic conditions.The project (21NRM06 EMC-STD) has received funding from the European Partnership on Metrology, co-financed by the European Union's Horizon Europe Research and Innovation Programme and by the Participating States. EMC Barcelona's project under grant number SNEO-20211223 has received funding from CDTI, which is supported by ''Ministerio de Ciencia e Innovación'' and financed by the European Union – NextGenerationEU – through the guidelines included in the "Plan de Recuperación, Transformación y Resiliencia." Dr. Azpúrua has received funding from the StandICT.eu 2023 project, financed by the European Union's Horizon Europe - Research and Innovation Programme - under grant agreement no. 951972

EMC testing of electricity meters using real-world and artificial current waveforms

In 2015, the energy measurement of some static electricity meters was found to be sensitive to specific conducted electromagnetic disturbances with very fast current changes caused by highly nonlinear loads, leading to meter errors up to several hundred percent. This article describes new results on the electromagnetic compatibility (EMC) of 16 different meters from all over Europe when exposed to real-world disturbance signals. Those test signals were obtained from household appliances and onsite measurements at metered supply points all over Europe. The results show that also the interference signals recorded onsite can cause measurement errors as large as several hundred percent, even for meters that pass the present EMC standards. This unambiguously demonstrates that the present immunity testing standards do not cover the most disturbing conducted interference occurring in present daily-life situations due to the increased use of nonlinear electronics. Furthermore, to enable the adoption of potential new test waveforms in future standards for electricity meter testing, artificial test waveforms were constructed based on real-world waveforms using a piece-wise linear model. These artificial test waveforms were demonstrated to cause meter errors similar to those caused by the original real-life waveforms they are representing, showing that they are suitable candidates for use in improved standardization of electricity meter testing.Postprint (published version

Full time-domain electromagnetic interference measurements and applications

This thesis presents a technology that has been called the Full Time-Domain Electromagnetic Interference measurement systems and its applications. Full TDEMI measurement systems are an implementation of an FFT-based receiver that enables the usage of oscilloscopes for EMI measurements. They follow the virtual instrumentation approach for transforming oscilloscopes into a compliant CISPR 16-1-1 receiver. Full TDEMI measurement systems have been assessed for characterizing their performance using waveform oriented calibration procedures that bridge the gap between direct measurements in the time domain and the processed frequency domain magnitudes. As a result, the conformity of Full TDEMI receivers is attested with respect to the requirements defined in the standards. Full TDEMI systems have advantages over the conventional swept receivers for performing challenging measurements typical of EMI assessments. Time-domain captures enable full spectrum measurements that allow analyzing transient phenomena. The number of channels available in most oscilloscopes enable synchronous measurements that allow recording the EMI using a combination of transducers. Some of the applications of the multichannel EMI measurements are the single stage evaluation of the conducted EMI of all the EUT mains lines, the instantaneous measurement of the common-mode and the differential mode voltage noise, the concurrent conducted and radiated EMI measurements, and the parallelization of multi-antenna radiated emissions testing. Such alternative test methods, have improved the EMC testing process in a variety of industries by reducing the time and the efforts required for performing a complete EMI evaluation due to the following reasons. First, Full TDEMI measurements deliver faster results because the interferences' spectrum is simultaneously estimated for all the weighting detectors. Second, the number of measurement iterations is reduced because of the multichannel possibilities and also because of an agile identification of the worst case emissions. Thirdly, Full TDEMI measurement system are a cost-effective alternative to the real-time spectrum analysers. Full TDEMI measurement systems have extended the state-of-the-art with the expected maximum detector and the empirical interference decomposition. The expected maximum detector is a statistical measure of the most probable level of the peak emissions that is based on a time-frequency modelling of the measured EMI using the extreme value theory. Using the variability information of the EMI level at each frequency bin, the expected maximum detector estimates the equivalent max hold value of a random EMI. The expected maximum detector also provides a model for quantifying the uncertainty of peak detector measurement of stochastic EMI. The Empirical Interference Decomposition is a modified implementation of the Hilbert-Huang transform with time-gating capabilities that allow a heuristic determination of characteristic oscillatory patterns without neither domain transformation nor a predefined set of basis function. The EID has been used successfully for ambient noise cancellation purposes during outdoor EMI measurements, obtaining more than 20 dB of attenuation of the usual broadcasting signals. The fundamentals of the ANC by means of EID is the identification, in the time and in the frequency domain, of intrinsic modes of emissions that area attributable to the EUT while subtracting the residual modes from the measurement results. Applications of the Full TDEMI measurement systems have been published in recognized conferences and journal. From the reasons mentioned before, the Full TDEMI measurement technology has advantages for EMI testing, analyzing and troubleshooting. It provides a complementary approach to the typical measurements entirely focused in the frequency domain and it exhibits a level of maturity that could allow it to be standardized in forthcoming years.Esta Tesis comprende un compendio de contribuciones hechas por el autor al campo de la tecnología de medición de radiofrecuencia para la compatibilidad electromagnética. En particular, esta Tesis presenta una tecnología de sistemas medición de interferencias electromagnéticas completamente basado en dominio del tiempo (Full TDEMI) y algunas de sus aplicaciones más relevantes. Los sistemas de medición Full TDEMI son una implementación de un receptor de medida basado en FFT que permite el uso de osciloscopios para mediciones de interferencias electromagnéticas. Los sistemas de medición Full TDEMI siguen el enfoque de instrumentación virtual para transformar los osciloscopios de propósito general en un receptor de medida completamente funcional y conforme con la norma CISPR 16-1-1. Por un lado, esto es factible debido a las técnicas específicas de procesamiento de señales aplicadas sobre las adquisiciones en el dominio del tiempo utilizando una capa de software dedicada. Por otro lado, los sistemas de medida Full TDEMI se han evaluado exhaustivamente para caracterizar su rendimiento utilizando procedimientos novedosos de calibración orientados a formas de onda que acortan la brecha entre las magnitudes medidas en el dominio del tiempo y las aquellas procesadas en el dominio de frecuencia. Como resultado, se certifica la conformidad de los sistemas completos de medición TDEMI con respecto a los requisitos definidos en los estándares internacionales paramediciones EMI. Además, se ha demostrado que los sistemas de medición Full TDEMI ofrecen ventajas en comparación con los receptores de barrido convencionales para realizar varias medidas desafiantes típicas de las evaluaciones de emisiones electromagnéticas. Por ejemplo, las capturas de dominio de tiempo posibilitan mediciones de espectro completo que permiten un análisis adecuado de fenómenos transitorios. Del mismo modo, la cantidad de canales disponibles en la mayoría de los osciloscopios hace viables múltiples mediciones síncronas que para registrar las perturbaciones interferentes mediante una combinación de transductores. Algunas de las aplicaciones de la medición EMI multicanal son la evaluación de etapa única de la EMI conducida de todas las líneas de alimentación de los equipos bajo prueba (EUT), la medición instantánea del voltaje del ruido en modo común y en modo diferencial, las mediciones concurrentes de la EMI conducida y radiada y la paralelización de los ensayos de emisiones radiadas con múltiples antenas. Tales métodos de prueba alternativos, han mejorado significativamente el proceso de prueba de EMC en una variedad de industrias al reducir la cantidad de tiempo y los esfuerzos necesarios para realizar una evaluación completa del sistema principalmente debido a las siguientes razones. En primer lugar, las mediciones de EMI en el dominio del tiempo arrojan resultados más rápidos porque el espectro de interferencias se estima simultáneamente para todos los detectores de ponderación estándar necesarios para determinar el cumplimiento de los límites máximos de emisiones definidos en las respectivas normas de producto. En segundo lugar, el número de iteraciones de medición se reduce debido a las posibilidades multicanal y también debido a una identificación ágil del peor caso de las emisiones de un EUT que tiene diferentes modos de funcionamiento. En tercer lugar, el sistema Full TDEMI es una alternativa económica y versátil a los analizadores de espectro en tiempo real más avanzados en lo concerniente a mediciones EMI en el rango de pocos gigahertzios. Desde el punto de vista teórico, los sistemas de medición Full TDEMI han extendido el estado del arte, como en el caso de un par de contribuciones denominadas el detector de máximo esperado y la descomposición empírica de interferencias. El detector de máximo esperado es una medida estadística del nivel más probable de las emisiones pico que se basa en un modelado tiempo-frecuencia de las interferencias medidas utilizando la teoría del valor extremo. Usando la información de variabilidad del nivel de interferencia en cada componente de frecuencia, el detector de máximo esperado se puede usar para estimar el valor de retención máximo (max-hold) equivalente de una interferencia aleatoria. El detector demáximo esperado también proporciona un modelo que cuantifica la incertidumbre de lamedición del detector de picos ante interferencias estocásticas. La descomposición de interferencia empírica (EID) es una implementación modificada de la transformada de Hilbert-Huang con capacidades de sincronización de tiempo que permiten una determinación heurística de patrones oscilatorios característicos sin requerir transformación de dominio ni un conjunto predefinido de funciones base. La descomposición de la interferencia empírica se ha utilizado con éxito para la cancelación del ruido ambiental durante prueba de concepto de mediciones de EMI de al aire libre, obteniendo más de 20 dB de atenuación de las señales habituales de radiodifusión. El fundamento de la cancelación del ruido ambiental mediante EID es la identificación, en el tiempo y en el dominio de la frecuencia, de los modos de emisión intrínsecos que son atribuibles al EUT al restar los modos residuales (ruido ambiental) de los resultados de medición. Las contribuciones mencionadas se distribuyen en cuatro artículos de revista. Los resultados de medición complementarios y las aplicaciones de los sistemas de medición Full TDEMI también se han publicado en conferencias notables en el área. Por los motivos antes mencionados, la tecnología Full TDEMI tiene ventajas significativas para los ensayos, el análisis y la resolución de problemas de EMI. Asimismo, proporciona un enfoque complementario a las mediciones típicas completamente enfocadas en el dominio de la frecuencia y exhibe un nivel de madurez que podría permitir su estandarización en los próximos años

Reducción de interferencia electromagnética de filtros pasabajas de microondas

En este trabajo se diseñó y validó a través de simulaciones un filtro pasabajas usando una topología simétrica para reducir las emisiones de interferencia electromagnética (EMI), basándonos en la cancelación del campo electromagnético generado por corrientes antisimétricas. El filtro en cuestión se implementó en microcintas con frecuencia de corte 1.1 GHz. En primera instancia, se diseñó el filtro de la manera tradicional y luego se convirtió a un filtro simétrico, ambos fueron simulados con un simulador de onda completa para obtener sus respuestas en frecuencia, distribuciones de corriente y campo eléctrico en la zona lejana. Los resultados demostraron la eficacia del diseño en la reducción de las EMI y muestran el diseño simétrico como una técnica complementaria y de aplicación directa para lograr el cumplimiento de las normas de compatibilidad electromagnética (EMC)