Spectral leakage in dft

1. What is spectral leakage in DFT?
2. What is spectral leakage caused by?
3. What causes spectral leakage in FFT?
4. How do you fix spectral leakage?

What is spectral leakage in DFT?

Spectral leakage occurs when a non-integer number of periods of a signal is sent to the DFT. Spectral leakage lets a single-tone signal be spread among several frequencies after the DFT operation. This makes it hard to find the actual frequency of the signal.

What is spectral leakage caused by?

Spectral leakage results from an assumption in the fast Fourier transform (FFT) and discrete Fourier transform (DFT) algorithms that the time record exactly repeats throughout all time. Thus, signals in a time record are periodic at intervals that correspond to the length of the time record.

What causes spectral leakage in FFT?

Spectral leakage due to FFT is caused by: mismatch between desired tone and chosen frequency resolution, time limiting an observation. Understand the concept using hands-on examples.

How do you fix spectral leakage?

We have seen that spectral leakage is reduced by tapering the digital signal by a window function before the DFT takes place. A generalization of this technique is the short-time discrete Fourier transform (STDFT).