Fast Fourier Transform (FFT) Subroutine for Determining Frequency Response Data for Digital Simulations.

Abstract : A FFT (Fast Fourier Transform) computer subroutine using VAX-11 FORTRAN has been written to perform the FFT. The FFT algorithm used to write the FFT subroutine is an in-place, decimation in frequency, Radix-2 algorithm originally proposed by Gentlemen and Sande. The subroutine can be linked with a system simulation to provide the frequency spectrum impulse data as a part of the system simulation. The FFT subroutine is a very useful, fast computational algorithm which can be used with any digital system simulation when frequency spectrum processing is needed in the calculation of the system's frequency response. This report outlines the development and checkout of the FFT and computer subroutine. (Author)