w = blackman(L)
w = blackman(L,sflag)
Create a 64-point Blackman window. Display the result using
L = 64; wvtool(blackman(L))
L— Window length
Window length, specified as a positive integer.
sflag— Window sampling
Window sampling method, specified as:
'symmetric' — Use this option when using windows for
'periodic' — This option is useful for spectral
analysis because it enables a windowed signal to have the perfect periodic
extension implicit in the discrete Fourier transform. When
'periodic' is specified, the function computes a
window of length
L + 1 and returns the first
w— Blackman window
Blackman window, returned as a column vector.
The following equation defines the Blackman window of length N:
where M is N/2 when N is even and (N + 1)/2 when N is odd.
In the symmetric case, the second half of the Blackman window, M ≤ n ≤ N – 1, is obtained by reflecting the first half around the midpoint. The symmetric option is the preferred method when using a Blackman window in FIR filter design.
The periodic Blackman window is constructed by extending the desired window length by one sample to N + 1, constructing a symmetric window, and removing the last sample. The periodic version is the preferred method when using a Blackman window in spectral analysis because the discrete Fourier transform assumes periodic extension of the input vector.
 Oppenheim, Alan V., Ronald W. Schafer, and John R. Buck. Discrete-Time Signal Processing. Upper Saddle River, NJ: Prentice Hall, 1999, pp. 468–471.