Maximum flattened fractional delay filter based on farrow structure
Shuang Du, Yaoliang Song, Congwei Jin, Yuting Zhu · 2023
The fractional delay filters are widely used in beamforming of broadband signals; however, conventional digital fractional delay filters are associated with high computational complexity. The Farrow structure fractional delay filter features a multi-stage sub-filter parallel structure, where the fractional delay is not affected by the sub-filter coefficients, thereby minimizing computational complexity. Nevertheless, the conventional Farrow structure is plagued by considerable passband fluctuations and high-frequency errors. To tackle these concerns, this article proposes a Farrow structure fractional delay filter design approach based on the maximum flatness method. This technique employs the maximum flatness method to design Farrow structure sub-filters, thereby reducing high-frequency errors and passband fluctuations compared to the conventional Farrow structure.