하나 이상의 출력을 입력으로 재사용하는 필터This feedback typically results in an unnding impulse response (IIR Filter) Recursive filterIn signal processing, a recursive filter is a type of filter which reuses one or more of its outputs as an input. This feedback typically results in an unending impulse response (commonly referred to as infinite impulse response (IIR)), characterised by either exponentially growing, decaying, or sinusoidal signal output components.https://en.wikipedia.org/wiki/Recursive_filter