Digital Finite Impulse Response Notch Filter with Non-Zero Initial Conditions, Based on an Infinite Impulse Response Prototype Filter

Abstract

In this paper a concept of finite impulse response (FIR) narrow band-stop (notch) filter with non-zero initial conditions, based on infinite impulse response (IIR) prototype filter, is proposed. The filter described in this paper is used to suppress power line noise from ECG signals. In order to reduce the transient response of the proposed FIR notch filter, optimal initial conditions for the filter have been determined. The algorithm for finding the length of the initial conditions vector is presented. The proposed values of the length of initial conditions vector, for several ECG signals and interfering frequencies, are calculated. The proposed filters are tested using various ECG signals. Computer simulations demonstrate that the proposed FIR filters outperform traditional FIR filters with initial conditions set to zero.

AI-Enabled Electrocardiogram Analysis for Disease Diagnosis

“…The fixed range (50-60 Hz) makes removing power line interference easier. The typical solution is using a notch filter and their variant with the downside of adding a ripple to the ECG wave [38][39][40][41]. Some other solutions are adaptive filters, such as the Hilbert Huang Transform adaptive filter; the downside, in this case, is the requirement of a reference signal [42][43][44][45][46].…”

A Review on the State of the Art in Atrial Fibrillation Detection Enabled by Machine Learning

“…It can be caused by the electronic devices not grounded properly or other electronic devices in operation near the ECG device as shown in Figure 6 (b).PLI can be minimized by properly grounding the electric equipment or keeping other electronic devices away from the ECG recording device. Fixed notch filters like infinite impulse response (IIR) and finite impulse response (FIR) [58] and their variant like High-Q Comb FIR [59] are commonly used to removed PLI from ECG signal [56], [60]- [62]. Disadvantages of the fixed notch filter are that it modifies the ECG signal, produces ripples and also requires some fixed parameters.…”

Time-Varying IIR Notch Filter with Reduced Transient Response Based on the Bézier Curve Pole Radius Variability

“…The useful signal s(n) used in the procedure for determining the value of the starting pole radius is equal to zero. Therefore, this signal has been omitted in Equation (10). In the considered procedure the 50 Hz sine wave signal is used as an input signal.…”

“…The trade off between the duration of the transient response and the selectivity of notch filters has been examined in a few works. In [10,11] the authors introduce non-zero initial conditions to the output of notch filters. As a result, the transient response of these filters is considerably suppressed.…”