Note:
The use of 
sigwin.hann
creates a handle to a Hann window
object for use in spectral analysis and FIR filtering by the window
method. Object methods enable workspace import and ASCII file export
of the window values.
The symmetric Hann window of length N
is defined as:
$$w(n)=\frac{1}{2}\left(1\mathrm{cos}\frac{2\pi n}{N1}\right),\text{\hspace{1em}}0\le n\le M1$$
where M
is N/2
for N
even and (N+1)/2
for N
odd.
The second half of the symmetric Hann window $$M\le n\le N1$$ is obtained by flipping the first half around the midpoint. The symmetric option is the preferred method when using a Hann window in FIR filter design.
The periodic Hann window is constructed by extending the desired window length by one sample, constructing a symmetric window, and removing the last sample. The periodic version is the preferred method when using a Hann window in spectral analysis because the discrete Fourier transform assumes periodic extension of the input vector.
H = sigwin.hann
returns a symmetric Hann
window object H
of length 64.
H = sigwin.hann(
returns a symmetric Hann window object with length Length)
Length
. Length
requires
a positive integer. Entering a positive noninteger value for Length
rounds the length to the nearest integer. Entering
a 1 for Length
results in a window with
a single value of 1.
H = sigwin.hann(
returns a Hann window object
with sampling Length
,SamplingFlag
)Sampling_Flag
. The SamplingFlag
can be either 'symmetric'
or 'periodic'
.

Hann window length. Must be a positive integer. Entering a positive
noninteger value for 


generate  Generates Hann window 
info  Display information about Hann window object 
winwrite  Save Hann window object values in ASCII file 
Handle. To learn how copy semantics affect your use of the class, see Copying Objects in the MATLAB^{®} Programming Fundamentals documentation.
Default length N = 64
symmetric Hann window:
H = sigwin.hann; wvtool(H)
Generate length N=128
periodic Hann window,
return values, and write ASCII file:
H = sigwin.hann(128,'periodic'); % Return window with generate win = generate(H); % Write ASCII file in current directory % with window values winwrite(H,'hann_128')
Oppenheim, Alan V., and Ronald W. Schafer. DiscreteTime Signal Processing. Upper Saddle River, NJ: Prentice Hall, 1989.