Elliptic Digital Filters Research Articles

EKG MORFOLOJİSİNE DAYALI ÖZELLİKLERİ KULLANAN ETKİLİ BİR ARİTMİK KALP ATIŞI SINI

Clinically, analyzing the ECG records is often quite time-consuming. Therefore, it is important to perform rapid analysis and detect abnormalities in ECG signals such as arrhythmias. For this reason, computer-aided diagnostic systems are being developed. With the developed systems, abnormalities in the ECG record can be easily detected. Thus, the developed systems are useful for clinicians in determining the diagnosis and treatment methods of heart diseases. In this study, an IIR based elliptic digital filter was used for removing the baseline wander in the ECG signal. Morphologically based features of the ECG signal are extracted. Then, the most meaningful of these features were selected by using the SelectKBest method and the f_ classif score function. Five basic arrhythmias labelled according to the AAMI standard have been classified using machine learning methods utilizing these feature data sets. Logistic Regression (LR), Linear Discriminant Analysis (LDA), Support Vector Machine (SVM) and Multi Layer Perceptron (MLP) machine learning methods were used as classifiers for arrhythmia diagnosis. The performance results obtained with these classifiers were examined and the LR method, which predicts the five basic arrhythmias as satisfactorily high was proposed as a classifier. The performance results of the LR method were obtained as Accuracy 99.766%, Sensitivity 99.416%, Specificity 99.854% and F1-Score 99.416%. In this study, the arrhythmia diagnosis method has been proposed which predicts five basic arrhythmias satisfactorily high. The proposed method can be used beneficially in computer-aided diagnostic systems. In this study, Google Colaboratory was used for the software and hardware needs of machine learning methods.

Design of computationally efficient elliptic IIR filters with a reduced number of shift-and-add operations in multipliers

In this paper, a new design method for elliptic IIR filters that provides the implementation of half of the multiplication constants with few shifters and adders is proposed. An IIR filter, when derived by the bilinear transformation from an elliptic minimal Q-factor analog prototype, has its z-plane poles on the circle that is orthogonal to the unit circle and has the center on the real axis of the plane. Due to this property, the center of the circle can be used as a parameter for the representation of a pole, whereas the second parameter is the radius of the pole. It is shown in this paper that the center of the circle is uniquely determined by the frequency for which the filter attenuation is 3 dB. This result is used for the realization based on the parallel connection of two all-pass networks. It is shown that all second-order all-pass sections can be implemented with one common multiplication constant determined by the center of the circle. The design method is presented that, by an appropriate distribution of a margin in the filter performance, predetermines the value of the common constant according to the desired number of shift-and-add operations. This way, half of the multipliers are replaced with a limited number of shifters and adders. Conventional computer programs for IIR elliptic digital filters can be used. The direct approach for the distribution of the z-plane poles among two all-pass functions is developed. The application and efficiency of the proposed design method are demonstrated by examples.

Universal digital biquads which are free of limit cycles

Two second-order, multiple-output digital-filter structures are described which realize simultaneously a low-pass, a high-pass, a bandpass, a notch, and an all-pass transfer function. The two structures can be stabilized with respect to limit-cycle oscillations by employing the techniques of magnitude truncation and controlled rounding, and each uses four multipliers and two unit delays. The two structures are attractive for VLSI implementation since each can serve as the basis of a versatile, universal digital-filter chip which can be used for the implementation of Butterworth, Chebyshev, and elliptic digital filters and also for the design of digital equalizers.

A multi-output second-order digital filter structure for VLSI implementation

A multi-output second-order digital filter structure without zero-input and constant-input oscillations is presented. It could be used for the realization of low-pass, high-pass, band-pass, and band-stop Butterworth, Chebyshev, and elliptic digital filters, and all-pass digital filters. The overall structure consists of two delays, three multipliers, and nine adders, which could be adopted for VLSI implementation.

Universal multiple-output second-order digital filter

A universal, second-order, digital-filter structure is proposed, which realises simultaneously a lowpass, a highpass, a bandpass, a notch and allpass transfer function. The structure uses two unit-delays and four multipliers, and is quite attractive for VLSI implementation since a versatile universal chip can be fabricated, which can be used for the implementation of Butterworth, Chebyshev and elliptic digital filters as well as digital equalisers.

Erratum: Design of elliptic digital filters: prescribed specifications

Erratum: Design of elliptic digital filters: prescribed specifications

An algorithm to evaluate the L<inf>∞</inf>norm for some common filters

The L <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∞</inf> norm is used in some algorithms to determine the ordering of the pole-zero sections of cascade digital filters. This note develops simple expressions that easily evaluate the L <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∞</inf> norm entirely in the Z-domain for filters having zeros on the unit circle (i.e., Butterworth, Chebyshev, and elliptic digital filters designed using the bilinear Z-transformation).

Design of elliptic digital filters: prescribed specifications

The design of elliptic digital filters through the bilinear transformation is considered. Sets of formulas are derived which can be used to design filters satisfying prescribed specifications. A simple design procedure based on these formulas is then described. The procedure is illustrated by designing an 8th-order bandpass filter and a 10th-order bandstop filter.

Optimisation of digital filters in the discrete space of coefficients

A method is described for the minimization of the coefficient word lengths for an elliptic digital filter implemented in fixed point by the cascade structure, and some typical examples are given.

Elliptic digital filters

A synthesis procedure is given for elliptic digital filters of order 2q, q=1, 2, 3…. The pulse transfer function is obtained in the form of biquadratic products in z−1. An example illustrates how this method is used to synthetise an elliptic digital filter.