Suppression of narrowband interference generated by the power supply of the railway systems in public defibrillators devices

Abstract

A specific problem using the public access defibrillators arises at the railway stations. Some countries as Germany, Austria, Switzerland, Norway, Sweden and Slovenia are using AC railroad net power-supply system with rated frequency of 16.6(6) Hz, frequency modulated from 15.69 Hz to 17.36 Hz. The power supply frequency contaminates the electrocardiogram (ECG). It is difficult to be suppressed or eliminated due to the fact that it considerably overlaps the frequency spectra of the ECG. The interference impedes the automated decision of the public access defibrillators whether a patient should be (or should not be) shocked. The aim of study of this thesis is the suppression of the 16.6(6) Hz interference generated by the power supply of the railway systems in few central european countries. For this purpose, an adaptive filter and a band-stop filter are used and the results obtained are compared in order to get the most suitable solution.