DFT is basically a frequency sampling of Discrete Time Fourier Transform that produces periodic results. This is because a finite sequence of equally spaced samples of a function can be converted into equivalent length sequences of equally spaced samples. An approximate frequency spectrum of a signal can be obtained using DFT Algorithm.If the length of signal is increased then its DFT produces more compressed frequency spectrum. So we use zero padding to reduce the frequency spacing in the output spectrum. This reduces the approximation error.
Which is faster DITFFT or DIFFFT?
ReplyDeleteIn DITFFT the input need to be rearranged which is time consuming as far as the algorithm is concerned.
DeleteIn practice there's no major difference in implementation as far as no. of steps and calculations are concerned.But the hardware implementation gets changed in both the cases.For certain FFT variants hardware implementation is much more optimized.
ReplyDeleteRefer this: http://www.ti.com/lit/an/spra152/spra152.pdf
Informative content
ReplyDeleteThanks.
DeleteDFT is a generalized complex computation method for frequency domain analysis. Here, complex numbers are used as a signal is represented as a sum of sines and cosines which have a mutual 90 degree phase shift.
ReplyDeleteRepresentation using sine and cosine terms is what we call definition of Fourier Transform. DFT is its frequency sampling in discrete domain.
DeleteThe magnitude spectrum is periodic due to the characteristic of twiddle factor
ReplyDeleteExactly. Hence the input to a DFT block need not be necessarily periodic.
DeleteBut the output will always be periodic.
Deletediscrete Fourier transform (DFT) is a specific kind of discrete transform, used in Fourier analysis.It transforms one function into another, which is called the frequency domain representation, or simply the DFT
ReplyDeletewell written
ReplyDelete