w = blackman(N)
w = blackman(N,SFLAG)
w = blackman(
N-point symmetric Blackman window in the
a positive integer.
w = blackman(N,
N-point Blackman window using the
window sampling specified by
'sflag', which can
'periodic' flag is useful for DFT/FFT
purposes, such as in spectral analysis. The DFT/FFT contains an implicit
periodic extension and the periodic flag enables a signal windowed
with a periodic window to have perfect periodic extension. When
blackman computes a length
and returns the first
N points. When using windows
for filter design, the
'symmetric' flag should
See Algorithms for a description of the difference between the symmetric and periodic windows.
If you specify a one-point window (set
N = 1),
1 is returned.
Create a 64-point Blackman window. Display the result using
L = 64; wvtool(blackman(L))
The following equation defines the Blackman window of length N:
where M is N/2 for N even and (N + 1)/2 for N odd.
In the symmetric case, the second half of the Blackman window M ≤ n ≤ N – 1 is obtained by flipping 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.
Usage notes and limitations:
Window length must be a constant. Expressions or variables are allowed if their values do not change.