We are now in a position to consider the various approaches to the design of digital filters. The two types of filter, FIR and IIR, have very different design methods and so will be considered separately. In this chapter we will focus on the techniques used to design IIR or recursive filters. We begin with a very brief résumé of filter essentials.
Before we move on to the design of digital filters, it is probably worth having a very brief recap on filters.
An ideal filter will have a constant gain of at least unity in the passband and a constant gain of zero in ...