GABWIN Compute a Gabor window from text or cell array
Usage: [g,info] = gabwin(g,a,M,L);
[g,info]=GABWIN(g,a,M,L) computes a window that fits well with the
specified number of channels M, time shift a and transform length
L. The window itself is specified by a text description or a cell array
containing additional parameters.
The window can be specified directly as a vector of numerical
values. In this case, GABWIN only checks assumptions about transform
sizes etc.
[g,info]=GABWIN(g,a,M) does the same, but the window must be a FIR
window, as the transform length is unspecified.
GABWIN(g,a,M,L,lt) or GABWIN(g,a,M,[],lt) does as above but for a
non-separable lattice specified by lt. Please see the help of
MATRIX2LATTICETYPE for a precise description of the parameter lt.
The window can be specified as one of the following text strings:
'gauss' Gaussian window fitted to the lattice,
i.e. tfr=a*M/L.
'dualgauss' Canonical dual of Gaussian window.
'tight' Tight window generated from a Gaussian.
In these cases, a long window is generated with a length of L.
It is also possible to specify one of the window names from FIRWIN. In
such a case, GABWIN will generate the specified FIR window with a length
of M.
The window can also be specified as cell array. The possibilities are:
{'gauss',...}
Additional parameters are passed to PGAUSS.
{'dual',...}
Canonical dual window of whatever follows. See the examples below.
{'tight',...}
Canonical tight window of whatever follows.
It is also possible to specify one of the window names from FIRWIN as
the first field in the cell array. In this case, the remaining
entries of the cell array are passed directly to FIRWIN.
Some examples: To compute a Gaussian window of length L fitted for a
system with time-shift a and M channels use:
g=gabwin('gauss',a,M,L);
To compute Gaussian window with equal time and frequency support
irrespective of a and M*:
g=gabwin({'gauss',1},a,M,L);
To compute the canonical dual of a Gaussian window fitted for a
system with time-shift a and M channels:
gd=gabwin('gaussdual',a,M,L);
To compute the canonical tight window of the Gaussian window fitted
for the system:
gd=gabwin({'tight','gauss'},a,M,L);
To compute the dual of a Hann window of length 20:
g=gabwin({'dual',{'hann',20}},a,M,L);
The structure info provides some information about the computed
window:
info.gauss
True if the window is a Gaussian.
info.tfr
Time/frequency support ratio of the window. Set whenever it makes sense.
info.wasrow
Input was a row window
info.isfir
Input is an FIR window
info.isdual
Output is the dual window of the auxiliary window.
info.istight
Output is known to be a tight window.
info.auxinfo
Info about auxiliary window.
info.gl
Length of window.
Url: http://ltfat.github.io/doc/gabor/gabwin.html
See also: pgauss, firwin, wilwin.
Package: ltfat