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5.3.1.3
Selecting FFT Window
Using windows can eliminate the spectral leakage in the FFT spectrum. The FFT algorithm assumes that the YT
waveform repeats all the time. When the number of cycles is integral (1, 2, 3 ...), the YT waveform starts and ends at
the same amplitude and there are no discontinuities in the signal shape.
If the number of cycles is nonintegral, the YT waveform starts and ends at different amplitudes and transitions
between the start and end points will cause discontinuities in the signal that introduces high-frequency transients.
Applying a window to the YT waveform changes the waveform so that the start and stop values are close to each
other, which reduces the discontinuities.