Farrow structure for complex digital Hilbert filter of low complexity

Abstract

In this paper we analyze the complexity of Hilbert Transform Filters (HTF) composed of two Variable Fractional Delay Filters Rotated (VFDR). HTF combines both Hilbertian and fractional delay filtering in one step. One of the most important advantages of this system lies in the usage of a Farrow structure, which allows on-line tuning of filter characteristics. To reduce the complexity of designed filter we employ the symmetry of the coefficients representing the impulse response and ability to share the delay elements within the branch filters and we use the same filters in both real and imaginary part of the system.