Abstract:Variable fractional delay filters are widely used in delay compensation technologies due to their ability to achieve arbitrary fractional delay transformations. However, due to the high complexity of solving its filter coefficients and poor adaptability, its application in engineering is severely limited. To address this challenge, this paper proposes a method to flexibly change the performance of fractional time-delay filters by adjusting the filter parameters under the condition of low computational complexity, and completes the FPGA simulation verification. The method precisely controls the window shape by adjusting the width factor of the window function, thereby optimizing the time-frequency characteristics of the filter at different orders and providing more accurate frequency selectivity compared to traditional methods. In addition, this paper adopts the orthogonal triangular decomposition least squares matrix method to solve the filter coefficients, and the designed filter requires only one matrix inverse under the condition of guaranteeing the accuracy of group delay, which effectively avoids the complex mathematical operations such as partial derivatives and double integration. Simulation results show that the method proposed in this paper reduces the computational complexity by one order of magnitude compared with the existing methods under the condition of maintaining the same delay accuracy, with the maximum magnitude error reaching -104 dB and the maximum group delay error reaching 2.34×10-4. FPGA verification results show that the design method has low hardware computational resource consumption, greatly improving the efficiency of the design of the Farrow filter.