窓関数
Blackman‐Nuttall window。
w ( x ) = 0.3635819 − 0.4891775 cos  2 π x + 0.1365995 cos  4 π x − 0.0106411 cos  6 π x , if 0 ≤ x ≤ 1 {\displaystyle w(x)=0.3635819-0.4891775\cos 2\pi x+0.1365995\cos 4\pi x-0.0106411\cos 6\pi x,\ {\mbox{if }}0\leq x\leq 1}