The approximation that was given in (2.24) conforms to a particular type of approximation known as a Padé rational approximation[Bak75]. Padé approximations have long been a subject of interest in numerical analysis1. Although several forms of approximating functions exist, including polynomial and exponential approximations, Padé approximation employs a rational approximant. Padé approximations may not be always well-suited to general mathematical functions, but their applicability to network transfer functions is particularly appealing since these functions are in a rational form (as is a network transfer function), and the poles of the Padé approximant approach the poles of the system rather well.
Unable to display preview. Download preview PDF.