Howtosignalprocessing
- What is non uniform fast Fourier transform?
- How is DFT calculated in FFT?
- What is the drawback of DFT?
- How many samples do I need for FFT?
What is non uniform fast Fourier transform?
In applied mathematics, the nonuniform discrete Fourier transform (NUDFT or NDFT) of a signal is a type of Fourier transform, related to a discrete Fourier transform or discrete-time Fourier transform, but in which the input signal is not sampled at equally spaced points or frequencies (or both).
How is DFT calculated in FFT?
fft , with a single input argument, x , computes the DFT of the input vector or matrix. If x is a vector, fft computes the DFT of the vector; if x is a rectangular array, fft computes the DFT of each array column. Compute the DFT of the signal and the magnitude and phase of the transformed sequence.
What is the drawback of DFT?
In the Fourier analysis of mixed-structure signals, the disadvantages of DFT are most significantly manifested. These disadvantages are picket-fence, leakage, aliasing effects and amplitude modulation spectrum.
How many samples do I need for FFT?
The number of samples (N) in the FFT must be an integer power of 2. Therefore, N = 2p, where p is a positive integer. This rule minimizes the number of multiplications—and therefore the computation time—needed to compute the coefficients of the Fourier series.
