APPARATUS AND METHOD OF PIPELINED FAST FOURIER TRANSFORM USING RADIX 2 SQUARE SUPPORTING VARIABLE INPUT SIZES

摘要

A device and a method for performing pipelined FFT(Fast Fourier Transform) allowing variable input sizes with radix-2 square are provided to perform a usual 2^n-point FFT operation with a small occupation area and complexity by using a radix-2^2 structure. A first stage(501-1) includes a plurality of first multiplexers, which switches a signal path to enable an input signal to be inputted to a second butterfly connected to a twiddle multiplier and be output through an I/Q exchanger without passing a first butterfly connected to the I/Q exchanger. At least one intermediary stage(501-2) includes a plurality of second multiplexers, which switches the signal path to multiply the input signal passing the first butterfly by a twiddle factor and perform an I/Q exchange operation to the signal passing the second butterfly. The last stage(501-n) includes the multiplier and a plurality of third multiplexers switching the signal path to multiply the input signal passing the first butterfly by the twiddle factor and multiply the signal passing the second butterfly by 'I'. A controller controls a switching operation of the multiplexers according to a signal flow.