Finite Impulse Response Filter
A filter with 0 poles. For any finite input you receive a finite output. See [see page 5, here].
FIR filters are defined as a weighted sum of the last N inputs, because poles are defined by previous outputs and if there're no poles then no previous outputs are used.
See [see page 5, here] for advantages/disadvantages. Highlights:
- These filters are stable (they eventually decay to zero).
- Generally require more coefficients (outputs of previous filterings).