Pros and Cons of Classical IIR design methods
The following quick reference guide is aimed at providing developers with a quick overview of the pros and cons of the four Classical IIR design methods, i.e. Butterworth, Chebyshev I, Chebyshev II and Elliptic.
The frequency response charts shown below, show the differences between the various design prototype methods for a 5th order lowpass filter with the same specifications. As seen, the Butterworth response is the slowest to roll-off and the Elliptic the fastest.
Butterworth (5th order)
Filter characterstics
Elliptic (5th order)
Filter characterstics
Chebyshev type I (5th order)
Filter characterstics
Chebyshev type II (5th order)
Filter characterstics
The Bessel prototype is not supported, as the Bilinear transform warps the linear phase characteristics. However, a Bessel filter design method is available in ASN FilterScript