Improved Sliding DFT Filter With Fractional and Integer Frequency Bin-Index

This article presents a modified and improved filter structure based on the sliding DFT by changing the comb filter coefficient to positive and changing the comb filter delay from
$N$
to
$N/2$
. The proposed filter structure is able to track the input signal within half a cycle as compared to the conventional sliding DFT filter, which takes one complete cycle. The improved filter can be tuned to both the fractional as well as integer bin indices without having any impact on the computational complexity. The present work experimentally verifies the practical feasibility of the proposed filter by implementing it in a field programmable gate array.