▁in ▁the ▁design ▁of ▁digital ▁filters , ▁in ▁particular ▁to ▁convert ▁an ▁" ide al " ▁imp ulse ▁response ▁of ▁infinite ▁duration , ▁such ▁as ▁a ▁s inc ▁function , ▁to ▁a ▁finite ▁imp ulse ▁response ▁( FI R ) ▁filter ▁design . ▁ ▁That ▁is ▁called ▁the ▁window ▁method . ▁ ▁Statistics ▁and ▁curve ▁fitting ▁▁ ▁Window ▁functions ▁are ▁sometimes ▁used ▁in ▁the ▁field ▁of ▁statistical ▁analysis ▁to ▁restrict ▁the ▁set ▁of ▁data ▁being ▁analyz ed ▁to ▁a ▁range ▁near ▁a ▁given ▁point , ▁with ▁a ▁ ▁weight ing ▁factor ▁that ▁dimin ishes ▁the ▁effect ▁of ▁points ▁farther ▁away ▁from ▁the ▁portion ▁of ▁the ▁curve ▁being ▁fit . ▁In ▁the ▁field ▁of ▁ ▁Bay esian ▁analysis ▁and ▁curve ▁fitting , ▁this ▁is ▁often ▁referred ▁to ▁as ▁the ▁kernel . ▁ ▁Rect angular ▁window ▁applications ▁ ▁Analysis ▁of ▁trans ients ▁▁ ▁When ▁analyz ing ▁a ▁trans ient ▁signal ▁in ▁modal ▁analysis , ▁such ▁as ▁an ▁imp ulse , ▁a ▁shock ▁response , ▁a ▁s ine ▁burst , ▁a ▁ch ir p ▁burst , ▁or ▁noise ▁burst , ▁where ▁the ▁energy ▁vs ▁time ▁distribution ▁is ▁extremely ▁une ven , ▁the ▁rect angular ▁window ▁may ▁be ▁most ▁appropriate . ▁ ▁For ▁instance , ▁when ▁most ▁of ▁the ▁energy ▁is ▁located ▁at ▁the ▁beginning ▁of ▁the ▁recording , ▁a ▁non - rect angular ▁window ▁at ten u ates ▁most ▁of ▁the ▁energy , ▁de grad ing ▁the ▁signal - to - no ise ▁ratio . ▁ ▁Harm onic ▁analysis ▁▁ ▁One ▁might ▁wish ▁to ▁measure ▁the