Zero-padding vs. nonzero-padding in computation of auto-correlation with FFT

1. Does zero padding affect FFT?
2. Why zero padding is needed in FFT?
3. Does zero padding improve FFT resolution?
4. Why zero padding is used in linear convolution?

Does zero padding affect FFT?

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.

Why zero padding is needed in FFT?

In addition to making the total number of samples a power of two so that faster computation is made possible by using the fast Fourier transform (FFT), zero padding can lead to an interpolated FFT result, which can produce a higher display resolution.

Does zero padding improve FFT resolution?

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.

Why zero padding is used in linear convolution?

Zero padding enables the use of a longer FFT, resulting in a larger FFT result vector. The frequency bins of a lengthier FFT result are more closely spaced in frequency. It can quickly compute linear convolutions using the FFT. It's used to make the FFT bigger for a power of two.