Abstract: Disclosed is a fast Fourier transform device of a wireless LAN orthogonal frequency division multiplexing (OFDM) system. The device comprises: an FFT/IFFT unit constituted with one hardware, for performing a fast Fourier transform (FFT) and an inverse fast Fourier transform (IFFT); and a control signal input unit for outputting a control signal for controlling an operation of the FFT/IFFT unit.

Abstract: A pipelined FFT (fast Fourier transform) processor including a CBFP (convergent block floating point) algorithm, includes an inverse multiplexer for inverse-multiplexing an 8K-/2K-point input data, a first to sixth radix-4 operation circuit for receiving an output of the inverse multiplexer and performing a butterfly operation, a multiplexer connected between the first and second radix-4 operation circuits and for selectively outputting an output of the inverse multiplexer or a first butterfly unit, a radix-2 operation circuit connected to the sixth radix-4 operation circuits and for performing a butterfly operation, a convergent block floating point circuit connected to respective output terminals of the radix-4 operation circuit and the radix-2 operation circuit and for scaling a butterfly operation result, an addition circuit for accumulation and adding scaling indexes outputted from the convergent block floating point circuit, and a decoder for scaling an output of the radix-2 operation circuit in accorda