# FFT

## Reducing FFT Scalloping Loss Errors Without Multiplication

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

"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)."

Synopsis:
C library for computing the discrete Fourier transform
Author(s):
Frigo, Matteo and Johnson, Steven G.

## ScopeDSP

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.

Synopsis:
FFT signal analysis software
Author(s):
Iowegian International

## How to interpolate the peak location of a DFT or FFT if the frequency of interest is between bins

### Problem

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).