sigwin.flattopwin Class
Namespace: sigwin
Construct flat top window object
Description
Note
The use of sigwin.flattopwin
is not recommended.
Use flattopwin
instead.
sigwin.flattopwin
creates a handle to a flat
top 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.
Construction
H = sigwin.flattopwin
returns a flat top
window object H
of length 64 with symmetric sampling.
H = sigwin.flattopwin(
returns
a flat top window object of length Length
)Length
with
symmetric sampling. Length
must be 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.flattopwin(
returns
a flat top window object Length
,SamplingFlag
)H
of length Length
with
sampling SamplingFlag
. The SamplingFlag
can
be either 'symmetric'
or 'periodic'
.
Properties
|
Flat top window length. Must be a positive integer. Entering
a positive noninteger value for |
|
|
Methods
generate | Generates flat top window |
info | Display information about flat top window object |
winwrite | Save flat top window in ASCII file |
Copy Semantics
Handle. To learn how copy semantics affect your use of the class, see Copying Objects in the MATLAB® Programming Fundamentals documentation.
Examples
Algorithms
The following equation defines the flat top window of length N
:
where M is N/2 for N even and (N + 1)/2 for N odd.
The second half of the symmetric flat top window is obtained by flipping the first half around the midpoint. The symmetric option is the preferred method when using a flat top window in FIR filter design by the window method.
The periodic flat top 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 flat top window in spectral analysis because the discrete Fourier transform assumes periodic extension of the input vector.
The coefficients are listed in the following table:
Coefficient | Value |
---|---|
a0 | 0.21557895 |
a1 | 0.41663158 |
a2 | 0.277263158 |
a3 | 0.083578947 |
a4 | 0.006947368 |
References
Oppenheim, Alan V., and Ronald W. Schafer. Discrete-Time Signal Processing. Upper Saddle River, NJ: Prentice Hall, 1989.