Abstract - Pedro Ramos

For many years, impedance measurements have been one of the most researched and developed fields in the measurement of electrical quantities. The relevance of impedance measurements is derived from the fact that the electrical impedance is a key parameter that describes the electrical characteristics of materials, circuits, components and the electrical output of many sensors.

Impedance Spectroscopy (IS) is widely used in science and industry because it describes the impedance variation within a certain frequency range of interest. Impedance measurement systems are constantly being improved to take advantage of new developments in ADC capabilities and in the processing capabilities of new microcontrollers/processors. These factors have led to the development of small portable embedded impedance measurement systems that span multiple frequency decades and/or impedance ranges. At the core of these developments is also the development of new signal processing algorithms that can be executed in the device without the need for offline analysis and that can deliver in real-time important real-time estimates.

In this presentation, examples of impedance measurement methods are described together with examples from implementations of portable embedded impedance measurement systems. The algorithms used to extract, from the ADC measured samples, the impedance values are analyzed. To conclude, algorithms that can estimate, from the impedance frequency response, the equivalent circuit parameters are presented.

Pedro M. Ramos was born in Lisbon, Portugal, in 1972. Received the Diploma and the Master’s and Ph.D. degrees in electrical and computer engineering from Instituto Superior Técnico, University of Lisbon - UL (formerly Technical University of Lisbon), Lisbon, Portugal, in 1995, 1997, and 2001, respectively. Associate Professor with habilitation at Instituto Superior Técnico, UL and Senior Researcher of the Instrumentation and Measurement Research Group at the Instituto de Telecomunicações. Current research interests include impedance measurements, impedance spectroscopy, sine-fitting algorithms, automatic measurement systems, power-quality monitoring/measurements, determination of uncertainty in measurement systems, and non-destructive electronic measurement systems. Member of IMEKO TC4—Measurement of Electrical Quantities since 2006, Scientific Secretary of IMEKO T4 in 2012-2014 and the Vice-Chair of IMEKO TC4 in 2015-2018. IEEE Senior Member since 2013.