5.23.20  Tukey window function : tukey_window

tukey_window takes as arguments a real vector v of length n and optionally a real number α∈[0,1] (by default α=0.5 ) and/or an interval n₁ .. n₂ (with default values n₁=0 and n₂=n−1 ), and returns the elementwise product of the vector [v_n1,…,v_n2] and the vector w of length N=n₂−n₁+1 defined by

where β=α (N−1)/2 , for k=0,1,…,N−1 . When α=0 the rectangular window function (on-off windowing) is obtained, and the case α=1 corresponds to the Hann window function. For example, input :

followed by scatterplot(L).