Archivo: Spectral leakage caused by "windowing"

Descripción: The purpose of this image is to show that windowing a sinusoid causes spectral leakage, even if the sinusoid has an integer number of cycles within a rectangular window. The leakage is evident in the 2nd row, blue trace. It is the same amount as the red trace, which represents a slightly higher frequency that does not have an integer number of cycles. When the sinusoid is sampled and windowed, its discrete-time Fourier transform also suffers from the same leakage pattern. But when the DTFT is only sampled, at a certain interval, it is possible (depending on your point of view) to: (1) avoid the leakage, or (2) create the illusion of no leakage. For the case of the blue sinusoid (3rd row of plots, right-hand side), those samples are the outputs of the discrete Fourier transform (DFT). The red sinusoid DTFT (4th row) has the same interval of zero-crossings, but the DFT samples fall in-between them, and the leakage is revealed.
Título: Spectral leakage caused by "windowing"
Créditos: Trabajo propio
Autor(a): Bob K
Permiso: Yo, el titular de los derechos de autor de esta obra, la publico en los términos de la siguiente licencia:
Términos de Uso: Creative Commons Zero, Public Domain Dedication
Licencia: CC0
Enlace de Licencia: http://creativecommons.org/publicdomain/zero/1.0/deed.en
¿Se exige la atribución?: No