Active Circuit Design of a Fractional Order Butterworth Filter[J]. Acta Electronica Sinica, 2018, 46(5): 1160-1165. DOI: 10.3969/j.issn.0372-2112.2018.05.021.
the transfer function of the fractional low-pass filter is approximated as a Butterworth filter.The coefficients of the transfer function are calculated after determining the order and the cutoff frequency.Then
the circuit design
simulation and circuit implementation are based on the transfer function.In this paper
the circuit in any order can be implemented by changing few parts of the circuit which has a strong flexibility.