Practical filters attenuate over a finite frequency range rather than cutting off instantly.

Evidence

The effects of these four types of filter are shown in Figure 1.56 and one can see that a bank of band-pass filters are the most appropriate for analyz­ ing the spectrum of a sound wave. Note that although practical filters have specified cut-off frequencies which are determined by their design, they do not cut off instantly as the frequency changes. Instead they take a finite fre­ quency range to attenuate the signal. — David Howard, Jamie Angus, coustics and Psychoacoustics, 469

Categorization

• XREF: connects to: Filters attenuate gradually over a frequency range rather than cutting sharply — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 471