The Discrete Fourier Transform, Part 1.
Douglas A. Lyon · The Journal of Object Technology · 2009
This paper describes an implementation of the Discrete Fourier Transform (DFT) and the Inverse Discrete Fourier Transform (IDFT).We show how the computation of the DFT and IDFT may be performed in Java and show why such operations are typically considered slow.This is a multi-part paper, in part 2, we discuss a speed up of the DFT and IDFT using a class of algorithms known as the FFT (Fast Fourier Transform) and the IFFT (Inverse Fast Fourier Transform).Part 3 demonstrates the computation of the PSD (Power Spectral Density) and applications of the DFT and IDFT.The applications include filtering, windowing, pitch shifting and the spectral analysis of re-sampling.