[Elimination on Power Line Interference from ECG Signal Using Combined Double-sided Narrow-band Notch Filter].

The aim of current research was to find negative effects caused by eliminating power line interference in ECG signal with narrow-band recursive notch filter and to search for a filtering method that will solve a problem of signal distortion. During the study the method of ECG filtering with narrow-band recursive filter was described. The main negative attribute of this filter is a transient noise, also called "ringing" effect, as the reaction to a single impulse visible as R spikes on the ECG signals. It was discovered, that "ringing" effect appears after the impulse during forward filtering and before the impulse during backward filtering. Based on this effect we proposed a method the main idea of which was to build the finite signal with regions without transients.