The numerical calculation of the Rayleigh-Sommerfeld diffraction integral is investigated. The implementation of a fast-Fourier-transform (FFT) based direct integration (FFT-DI) method is presented, and Simpson's rule is used to improve the calculation accuracy. The sampling interval, the size of the computation window, and their influence on numerical accuracy and on computational complexity a...

A novel architecture FFT processor which can carry on 1-D FFT algorithm or 2-D FFT algorithm corresponding different size of FFT is proposed in this paper. The architecture is served as a scalable IP Core which is suitable for the heterogeneous multi-core SoC on chip application. The mixed architecture FFT processor achieves balance between high processing speed and resources. Compared with a c...

In this contribution we analyzed and compared the bit error rate performance for MC-CDMA (multicarrier codedivision multiple access) systems using IFFT/FFT (inverse fast Fourier transform/fast Fourier transform) and conventional correlation receiver over a frequency selective Rayleigh fading channel. Carrier frequency offset is considered in the analysis with either equal gain combining or maxi...

The FFT processor is a very important component in Orthogonal Frequency Division Multiplexing(OFDM) communication system. In this paper, we propose an efficient variable-length radix-8/4/2 FFT architecture for OFDM systems. The FFT processor is based on radix-8 FFT algorithm and also supports radix-4 or radix-2 FFT computation. The pipelined radix-8/4/2 butterfly unit computes radix-8 FFT algor...

The Fast Fourier Transform (FFT) is widely used in various digital signal processing applications. The performance requirements for FFT in modern real-time applications has increased dramatically due to the high demand on capacity and performance of modern telecommunication systems, where FFT plays a major role. Software implementations of FFT running on a general purpose computer can no longer...

Fructans are the main storage compound in Lolium perenne. To account for the prevailing neokestose-based fructan synthesis in this species, a cDNA library of L. perenne was screened by using the onion (Allium cepa) fructan:fructan 6G-fructosyltransferase (6G-FFT) as a probe. A full length Lp6G-FFT clone was isolated with significant homologies to vacuolar type fructosyltransferases and invertas...

an important section of range-doppler imaging algorithm in sar systems which needs large number of resources, memories and solution time, is fft on the azimuth dimension. in this paper, by decomposing the fft relation, and converting to smaller dimension ffts, implementation has been simplified. the proposed method, based on removing the extra phase factors reduces the resources, memories and s...

In this paper, how to parallelize the Pre-corrected FFT algorithm for solving the scattering problem of large scale is presented and discussed. The P-FFT technique developed by our group earlier was extended in the current analysis. To show the efficiency of the MPI-based parallelization algorithm, the experiment results are given in the latter part of the paper and various comparisons are made...

This application note describes the basics of the Fast Fourier Transform and how to use a Digital Signal Processing Library. The library and design example use Microchip’s dsPIC30F Series Digital Signal Controller, specifically the dsPIC30F3013. The Transform Analysis discusses the differences between the Discrete Fourier Transform (DFT) and the Fast Fourier Transform (FFT), and how the FFT is ...