Digital filters impulse response

Bialkowski, S. E., Real-Time Digital Filters Finite Impulse Response Filters, Anal. Chem. 60, 1988, 355A-361A. 

The perceptual approach. The perceptual approach seeks to reproduce only the perceptually salient characteristics of reverberation. Let us assume that the space of all percepts caused by reverberation can be spanned by N independent dimensions, which correspond to independently perceivable attributes of reverberation. If each perceptual attribute can be associated with a physical feature of the impulse response, then we can attempt to construct a digital filter with N parameters that reproduces exactly these N attributes. In order to simulate the reverberation from a particular room, we can measure the room response, estimate the N parameters by analyzing the impulse... 

In an efficient digital simulation, lumped loss factors of the form Gk (0)) are approximated by a rational frequency response Gk(c,mT). In general, the coefficients of the optimal rational loss filter are obtained by minimizing I Ylk (go) - Gk d r ) I with respect to the filter coefficients or the poles and zeros of the filter. To avoid introducing frequency-dependent delay, the loss filter should be a zero-phase, finite-impluse-response (FIR) filter [Rabiner and Gold, 1975], Restriction to zero phase requires the impulse response g.k(n) to be finite in length (i.e., an FIR filter) and it must be symmetric about time zero, i.e., ) k(-n) = gk(n). In most implementations, the zero-phase FIR filter can be converted into a causal, linear phase filter by reducing an adjacent delay line by half of the impulse-response duration. 

Small, G. W., Harms, A. C., Kroutil, R. T., Ditillo, J. T. Loerop, W. R. (1990) Design of optimized finite impulse-response digital-filters for use with passive Fourier-transform infrared interferograms. Ana/. Chem. 62, 1768-1777. 

Digital LTI Filters are often described in terms of their time domain difference equation, which relates input samples to output samples. The finite impulse response or FIR filter has the difference equation ... 

A digital filter with impulse response having infinite length is called an infinite impulse response (HR) filter. An important class of HR filters can be described by the difference equation... 

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