: ▁ ▁Other ▁polynomial ▁windows ▁ ▁Wel ch ▁window ▁▁ ▁The ▁Wel ch ▁window ▁consists ▁of ▁a ▁single ▁par abol ic ▁section : ▁ ▁The ▁defining ▁quadratic ▁polynomial ▁reaches ▁a ▁value ▁of ▁zero ▁at ▁the ▁samples ▁just ▁outside ▁the ▁span ▁of ▁the ▁window . ▁ ▁S ine ▁window ▁▁ ▁The ▁corresponding ▁ ▁function ▁is ▁a ▁cos ine ▁without ▁the ▁ π / 2 ▁phase ▁offset . ▁ ▁So ▁the ▁s ine ▁window ▁is ▁sometimes ▁also ▁called ▁cos ine ▁window . ▁As ▁it ▁represents ▁half ▁a ▁cycle ▁of ▁a ▁sin us oid al ▁function , ▁it ▁is ▁also ▁known ▁vari ably ▁as ▁half - s ine ▁window ▁or ▁half - cos ine ▁window . ▁ ▁The ▁aut oc or relation ▁of ▁a ▁s ine ▁window ▁produces ▁a ▁function ▁known ▁as ▁the ▁Boh man ▁window . ▁ ▁Power - of - s ine / cos ine ▁windows ▁▁ ▁These ▁window ▁functions ▁have ▁the ▁form : ▁ ▁The ▁# Rect angular ▁window ▁( ), ▁the ▁# S ine ▁window ▁( ), ▁and ▁the ▁Hann ▁window ▁() ▁are ▁members ▁of ▁this ▁family . ▁ ▁Cos ine - sum ▁windows ▁ ▁This ▁family ▁is ▁also ▁known ▁as ▁generalized ▁cos ine ▁windows . ▁ ▁In ▁most ▁cases , ▁including ▁the ▁examples ▁below , ▁all ▁coefficients ▁ak   ≥   0 .   ▁These ▁windows ▁have ▁only ▁ 2 K   +   1 ▁non - zero ▁N - point ▁D FT ▁coefficients , ▁and ▁they ▁are ▁all ▁real - valu ed . ▁ ▁Hann ▁and ▁Ham ming ▁windows ▁▁