The ``Finite'' in FIR

From Eq.(5.7), we can see that the impulse response becomes zero after time . Therefore, a tapped delay line (Fig.5.5) can only implement finite-duration impulse responses in the sense that the non-zero portion of the impulse response must be finite. This is what is meant by the term finite impulse response (FIR). We may say that the impulse response has finite support [52].

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written by 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.