What happens when N increases in N-point DFT [duplicate]

1. What is the effect of increasing size of DFT on spectrum?
2. What happens if we apply DFT twice to a signal?
3. What is N in N-point fft?
4. What is n-point in DFT?

What is the effect of increasing size of DFT on spectrum?

The DFT of the window is what would convolve with our original frequencies. As the time length of the window increases, the width of the main lobe of its transform in frequency gets more narrow (the nulls are located at 1/T) and therefore the frequency resolution increases.

What happens if we apply DFT twice to a signal?

Applying the DFT twice results in a scaled, time reversed version of the original series. The transform of a constant function is a DC value only.

What is N in N-point fft?

N is the number of points used to calculate the fft, it does not increase physical resolution but adds more point to the spectrum for more visual resolution, N is arbitrary.

What is n-point in DFT?

Definition. An N-point DFT is expressed as the multiplication , where is the original input signal, is the N-by-N square DFT matrix, and. is the DFT of the signal.