Question

What are two approaches to the design of IIR digital lters from analog lters? Explain them in a more detail.

Answer 1

The two possible approches for IIR filter desin are:

1. Transforamtion design method

i) The Sampling transformaiton or Impulse Invariant Method

ii) Bilinear Transformation method

2. Design using Optimization techniques

In transformation method, using a mapping between the analog and the dicrete frequienceis, we translate the dicrete filter specifications to that of an analog filter, and design the filter in analgo domain. And finally, the dicrete filter is obtained by transforming the designed analog filter.

The Optimization method designs the filter directly by setting the rational approximation of IIR filter as a nonlinear optimization problem