Editing Finite impulse response (section)

{{Short description|Type of filter in signal processing}}
In [[signal processing]], a '''finite impulse response''' ('''FIR''') '''filter''' is a [[filter (signal processing)|filter]] whose [[impulse response]] (or response to any finite length input) is of ''finite'' duration, because it settles to zero in finite time. This is in contrast to [[infinite impulse response]] (IIR) filters, which may have internal feedback and may continue to respond indefinitely (usually decaying).{{Citation needed|date=March 2023}}

The [[impulse response]] (that is, the output in response to a [[Kronecker delta]] input) of an N<sup>th</sup>-order discrete-time FIR filter lasts exactly <math>N+1</math> samples (from first nonzero element through last nonzero element) before it then settles to zero.

FIR filters can be [[discrete-time]] or [[Discrete time and continuous time|continuous-time]], and [[Digital data|digital]] or [[analog circuits|analog]].