A 1 + Iα/I Order Generalized Butterworth Filter Structure and Its Field Programmable Analog Array Implementation

Fractional-order Butterworth filters of order 1 + α (0 < α < 1) can be implemented by a unified structure, using the method presented in this paper. The main offered benefit is that the cutoff frequencies of the filters are fully controllable using a very simple method and, also, various types of filters (e.g., low-pass, high-pass, band-pass, and band-stop) could be realized. Thanks to the employment of a Field Programmable Analog Array device, the implementation of the introduced method is fully reconfigurable, in the sense that various types of filter functions as well as their order are both programmable.