Zero-pad before or after windowing for FFT

You must window your data, before zero-padding. The point of the windowing process is to smooth out the end-points of your data prior to taking the FFT, so that we reduce spectral leakage.

1. Why should I zero pad a signal before taking the Fourier transform?
2. What does zero padding do in FFT?
3. What is the effect of zero padding in frequency domain?
4. Does zero padding increase frequency resolution?

Why should I zero pad a signal before taking the Fourier transform?

Zero padding allows one to use a longer FFT, which will produce a longer FFT result vector. A longer FFT result has more frequency bins that are more closely spaced in frequency.

What does zero padding do in FFT?

``Zero-padding'' means adding additional zeros to a sample of data (after the data has been windowed, if applicable). For example, you may have 1023 data points, but you might want to run a 1024 point FFT or even a 2048 point FFT.

What is the effect of zero padding in frequency domain?

In this case, we can say “zero padding in the frequency domain results in an increased sampling rate in the time domain”.

Does zero padding increase frequency resolution?

In summary, the use of zero-padding corresponds to the time-limited assumption for the data frame, and more zero-padding yields denser interpolation of the frequency samples around the unit circle. Sometimes people will say that zero-padding in the time domain yields higher spectral resolution in the frequency domain.