Can the FFT representation of a signal be modified w/o creating glitches?

1. What the FFT analysis of a signal tells us about the signal?
2. How do you normalize FFT?
3. Why is FFT used in signal processing?

What the FFT analysis of a signal tells us about the signal?

The output of the FFT is a complex vector containing information about the frequency content of the signal. The magnitude tells you the strength of the frequency components relative to other components. The phase tells you how all the frequency components align in time.

How do you normalize FFT?

Normalise the fft by dividing it by the length of the original signal in the time domain. Zero values within the signal are considered to be part of the signal, so 'non-zero samples' is inappropriate. The length to use to normalise the signal is the length before adding zero-padding.

Why is FFT used in signal processing?

The FFT is used to process data throughout today's highly networked, digital world. It allows computers to efficiently calculate the different frequency components in time-varying signals—and also to reconstruct such signals from a set of frequency components.