Infinite impulse response

Infinite impulse response (IIR) is a fundamental property applying to many linear time-invariant systems that are distinguished by having an impulse response h ( t ) {\displaystyle h(t)} that does not become exactly zero past a certain point but continues indefinitely. This is in contrast to a finite impulse response (FIR) system, in which the impulse response does become exactly zero at times t > T {\displaystyle t>T} for some finite T {\displaystyle T} , thus being of finite duration.

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