Digital Filters

Abstract

One of the main purposes of digital filtering is to improve the quality of the signal. In this chapter, we give an overview of digital filtering. This often uses transformations in order to maintain the desired information in the presence of undesired signals that could corrupt it. Finite Impulse Response (FIR) and Infinite Impulse Response (IIR) filters are linear time invariant filters because the coefficients of the filters do not vary with time (i.e., they are time invariant) as well as because the signal is decomposed into a linear combination of basic signals (i.e., the linearity property). The FIR filter is non-recursive as this does not have feedback. In contrast the IIR filter has a recursive component because of feedback. The application of FIR filters to signal processing is more computationally involved than with IIR filters because FIR needs more coefficients than IIR filters.