In this tutorial, Richard G. Lyons, author of the best-selling DSP book Understanding Digital Signal Processing, discusses the estimation of time-domain sinewave peak amplitudes based on fast Fourier transform (FFT) data.
"FFTW is a C subroutine library for computing the discrete Fourier transform (DFT) in one or more dimensions, of arbitrary input size, and of both real and complex data (as well as of even/odd data, i.e. the discrete cosine/sine transforms or DCT/DST)."
ScopeDSP™ generates, reads, writes, windows, and plots sampled-data signals. It features an Arbitrary-N FFT algorithm to quickly perform Time-Frequency conversions, and it calculates many statistics in Time and Frequency. These features, plus a highly refined graphical user interface, make ScopeDSP the premier spectral analysis software tool for use by professionals working in Digital Signal Processing.
How to interpolate the peak location of a DFT or FFT if the frequency of interest is between bins
by Matt Donadio
If the actual frequency of a signal does not fall on the center frequency of a DFT (FFT) bin, several bins near the actual frequency will appear to have a signal component. In that case, we can use the magnitudes of the nearby bins to determine the actual signal frequency.
The Fast Fourier Transform is one of the most important topics in Digital Signal Processing but it is a confusing subject which frequently raises questions. Here, we answer Frequently Asked Questions (FAQs) about the FFT.
1. FFT Basics
1.1 What is the FFT?
The Fast Fourier Transform (FFT) is simply a fast (computationally efficient) way to calculate the Discrete Fourier Transform (DFT).