ABSTRACT
This chapter discusses the discrete Fourier transform, which is a digital version of Fourier transform and then window functions for performing discrete Fourier transform, and finally the algorithm of Fast Fourier Transform (FFT) and its programming. Many software packages of FFT have been developed in many programming languages, including FORTRAN, C, Basic, VBA, Mathematica, Maple, Python, and so on. The chapter also discusses some other interpolation techniques based on discrete Fourier transform. There are various types of interpolation, such as constant, triangle, bell and cubic B-spline interpolation. The chapter describes that zero-padding enables interpolation in the object domain. One of the common techniques for increasing the sampling rate in the spectrum domain is “zero padding”. The zero padding is to append zero-valued samples to the end of the original samples.
