IIR filters designed for comparison and minimum-order design exploration using Matlab

Digital signaling has become more and more applied in the field of electronics including radio, audio, and TV. It offers better accuracy, greater flexibility, increased storage capabilities and high-speed transmission of data of all kinds (including audio and video data) over long distances. The basic types of digital filters are finite impulse response (FIR) and infinite impulse response (IIR) filters. In this paper we model three different lowpass IIR filters: Butterworth, Chebyshev and elliptic using Matlab to compare their response and to explore minimum-order designs to specify the passband and the stopband in terms of the amount of tolerable ripple and frequencies.