Zero Padding of 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.

1. Why do we use zero padding in FFT?
2. What does zero padding do?
3. What is the effect of zero padding in frequency domain?
4. Does zero padding increase frequency resolution?

Why do we use zero padding in FFT?

Zero padding enables you to obtain more accurate amplitude estimates of resolvable signal components. On the other hand, zero padding does not improve the spectral (frequency) resolution of the DFT. The resolution is determined by the number of samples and the sample rate.

What does zero padding do?

Zero padding is a technique typically employed to make the size of the input sequence equal to a power of two. In zero padding, you add zeros to the end of the input sequence so that the total number of samples is equal to the next higher power of two.

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.