Comprehensive Study for Selection of Proper IIR Filter: Specifications Dependant Approach

Filters are greatly used in signal processing and telecommunication engineering to eliminate the unwanted part of the signal i.e. noise. In modern years, filters are used in mobile communication for reducing the speech echo or in biomedical test (like Electrocardiogram, EEG etc.) to reduce the noise associated with the signal. Filters can be classified in two broad domains-Analog and Digital. The hierarchy involved in digital filters are further divided into two types-Infinite Impulse Response (IIR) and Finite Impulse Response (FIR). IIR filter are known for their infinite impulse response, there are various specification upon which the design depends, and all the techniques are used in different types of filter design. In this paper we have described the three main IIR filters i.e. Butterworth filter, Chebyshev Type I, Chebyshev Type-II. As the number of specifications are large, we should have a proper way to determine a specific filter for a particular application. In order to find the best suited filter, a specification dependent approach has been discussed which compares the parameters with respect to passband ripple, stopband attenuation, order of the filter and slope. and outputs the best filter suitable for a specific application. All the simulations have been carried out using MATLAB 2015-a and the algorithm has been coded using Python - high level programming language.