Zero Padding in the Time Domain

Unlike time-domain interpolation [254], ideal spectral interpolation is very easy to implement in practice by means of zero padding in the time domain. That is,

Since the frequency axis (the unit circle in the plane) is finite in length, ideal interpolation can be implemented exactly to within numerical round-off error. This is quite different from ideal (band-limited) time-domain interpolation, in which the interpolation kernel is sinc; the sinc function extends to plus and minus infinity in time, so it can never be implemented exactly in practice.^3.9

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Subsections

• Practical Zero Padding

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About the Author: Julius Orion Smith III
Julius Smith's background is in electrical engineering (BS Rice 1975, PhD Stanford 1983). He is presently Professor of Music and Associate Professor (by courtesy) of Electrical Engineering at Stanford's Center for Computer Research in Music and Acoustics (CCRMA), teaching courses and pursuing research related to signal processing applied to music and audio systems. See http://ccrma.stanford.edu/~jos/ for details.