An Improved Design for the IIR-Type Digital Fractional Order Differential Filter

In this paper, a novel design for improving the fractional order differential filter is put forward. By analyzing the frequency characteristic of typical fractional order differential filter, it can be seen that these kinds of differential filters have merits and demerits respectively and also could be complementary each other. So based on these features, three kinds of novel first order differential filters are constructed by the interpolated method. And then we choose a differential filter from these three kinds of filters which has much better frequency characteristic, also the improved IIR-type fractional order differential filter will be obtained by the method of continuous fraction expansion (CFE). The experiment result shows that the frequency response of the improved fractional order differential filter is more approximate to the ideal fractional order differential filter. And it also shows that the method put forward in the paper can improve the performance of the fractional order differential filter obviously under the premise of not increasing the structure complexity of the filter.