Revisiting oustaloup's recursive filter for analog realization of fractional order differintegrators

Rational approximation of fractional order (FO) elements is becoming increasing important in fractional order control design and signal processing. Among the available continuous time and discrete rational approximation techniques, the Oustaloup's recursive filter which gives a band-limited realization of FO elements is the focus of the present study. Its another variant, commonly known as modified Oustaloup's filter is also analyzed in the same light, so as to produce low order analog approximation of FO differ-integrators.