| Title |
Constant Geometry Programmable Input Length 2-Dim FFT/IFFT System using Unified Twiddle Factor LUT |
| Authors |
이정훈(Jeonghun Lee) ; 유재희(Jaehee You) |
| DOI |
https://doi.org/10.5573/ieie.2026.63.6.65 |
| Keywords |
2-dimensional constant geometry FFT; LUT; Twiddle factor |
| Abstract |
An architecture for high-speed processing with reduced hardware complexity and power consumption is presented based on the Constant Geometry 2D parallel FFT, using an unified twiddle factor LUT with efficient feeding structure. The proposed architecture is optimized for a parallel structure with multiple PEs, enabling large input lengths. The architecture can be easily optimized for various applications due to configurable serial/parallel butterfly stage structure. Furthermore, the architecture can support both CGFFT and CGIFFT by reusing hardware. Since twiddle factors are duplicated across multiple PEs, an unified LUT that integrates same twiddle factors is proposed. Moreover, by exploiting the redundancy between the real and imaginary components of the twiddle factors, only the real parts are used to reduce the LUT size. A feeding structure is also designed to distribute the twiddle factors to each PE efficiently, and partial butterfly computation results are directly fed from the LUT, thereby reducing the number of required complex multipliers by 25%. The proposed approach greatly reduces the twiddle factor LUT amount to 0.003% compared with conventional FFT under the same throughput. The unified twiddle factor LUT and its feeding structure are verified through synthesis by Verilog. |