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The need for wireless communication has driven the communication systems to high performance. However, the main bottleneck that affects the communication capability is the Fast Fourier Transform (FFT), which is the core of most modulators. This paper presents FPGA implementation of pipeline digit-slicing multiplier-less radix 2 2 DIF (Decimation In Frequency) SDF (single path delay feedback) butterfly for FFT structure. The approach taken; in order to reduce computation complexity in butterfly multiplier, digit-slicing multiplier-less technique was utilized in the critical path of pipeline Radix-2 2 DIF SDF FFT structure. The proposed design focused on the trade-off between the speed and active silicon area for the chip implementation. The multiplier input data was sliced into four blocks each one with four bits to process at the same time in parallel. The new architecture was investigated and simulated with MATLAB software. The Verilog HDL code in Xilinx ISE environment was derived to describe the FFT Butterfly functionality and was downloaded to Virtex II FPGA board. Consequently, the Virtex-II FG456 Proto board was used to implement and test the design on the real hardware. As a result, from the findings, the synthesis report indicates the maximum clock frequency of 555.75 MHz with the total equivalent gate count of 32,146 is a marked and significant improvement over Radix 2 2 DIF SDF FFT butterfly. In comparison with the conventional butterfly architecture design which can only run at a maximum clock frequency of 200.102 MHz and the conventional multiplier can only run at a maximum clock frequency of 221.140 MHz, the proposed system exhibits better results. It can be concluded that on-chip implementation of pipeline digit-slicing multiplier-less butterfly for FFT structure is an enabler in solving problems that affect communications capability in FFT and possesses huge potentials for future related works and research areas. Key words— Pipelined digit-slicing multiplier-less; Fast Fourier Transform (FFT); Verilog HDL; Xilinx; Radix 22 DIF SDF FFT.

Most communications systems tend to achieve bandwidth, power and cost efficiencies to capable to describe modulation scheme. Hence for signal modulation orthogonal frequency division multiplexing (OFDM) transceiver is introduced to cover communications demand in four generation. However high performance Fast Fourier Transforms (FFT) as a main heart of OFDM acts beyond the view. In order to achieve capable FFT, design and realization of its efficient internal structure is key issues of this research work. In this paper implementation of high performance butterfly for FFT by applying digit slicing technique is presented. The proposed design focused on the trade-off between the speed and active silicon area for the chip implementation. The new architecture was investigated and simulated with the MATLAB software. The Verilog HDL code in Xilinx ISE environment was derived to describe the FFT Butterfly functionality and was downloaded to Virtex II FPGA board.