Frequency to Time FFT
A Frequency to Time FFT study step, which you can add to a time-dependent study, performs an inverse FFT (or, alternatively, the nonuniform Fourier transform) from the frequency domain (input) to the time domain (output). As the default solver it adds an FFT solver.
Syntax
model.study(stdname).create(fname, "FreqToTimeFFT");
model.study(stdname).feature(fname).set(pname,value);
Description
Study step.
The following properties are available.
Table 6-128: Properties for Study Settings.
Property
Value
Default
Description
addstatsol
on | off
off
Add stationary solution.
fftoutrange
Numeric vector
 
Output times.
fftscaling
cont | discrete
cont
Use a discrete or continuous scaling for the Fourier transform.
fftwinalpha
Real scalar
0.5
Window parameter for a Tukey window.
fftwincenterinv
Real scalar
50
Window center for a Gaussian window function.
fftwincutoff
Real scalar
1
Cutoff fraction for window function in [0, 1].
fftwindev
Real scalar
1
Standard deviation for a Gaussian window function.
fftwindowinv
on | off
off
Use window function.
fftwinexpr
String
1
Expression for window function (when set to fromexpr). Can be expressed in terms of t, freq, niterFFTin, and niterFFTout (if applicable).
fftwinmaxinv
Real scalar
100
Maximum (end) value for window.
fftwinmininv
Real scalar
0
Minimum (start) value for window.
fftwintypeinv
fromexpr | cutoff | rectangle | gauss | hamming | hanning | blackman | tukey
fromexpr
Method for window function.
linpmethod
sol | init
sol
Prescribe the input values using a solution or an initial expression.
linpsol
String
 
Solution that defines input values for the FFT study step.
linpsoluse
String
 
Subsolution that defines the input values for the FFT study step/FFT solver.
linpstudy
String
 
Study that defines input values for the FFT study step.
statmanualsolnum
Integer
1
Index to stationary solution to add.
statmethod
sol | init
sol
For an added stationary solution, use a solution or initial expression.
statsolnum
auto | first | last | interp | manual | positive integer
auto
Selection method for stationary solution to add.
statstudy
String
zero
Study from which the added stationary solution is chosen.
statt
String
 
Specify time for interpolated solution to add.
tunit
String
s
Time unit.
winpunit
String
Hz
Frequency unit for window.
Table 6-129: Properties for Physics and Variables Selection.
Property
Value
Default
Description
activate
String Map
 
See Physics and Variables Selection.
activateCoupling
String Map
 
See Physics and Variables Selection.
activaterom
String Map
 
See Physics and Variables Selection.
disabledcommon
Reference Array
 
See Physics and Variables Selection.
disabledcoordinatesystems
Reference Array
 
See Physics and Variables Selection.
disabledcoupling
Reference Array
 
See Physics and Variables Selection.
disabledpair
Reference Array
 
See Physics and Variables Selection.
disabledphysics
Reference Array
 
See Physics and Variables Selection.
disabledreduced
Reference Array
 
See Physics and Variables Selection.
disabledvariables
Reference Array
 
See Physics and Variables Selection.
disableFrameControl
Reference Array
 
See Physics and Variables Selection.
discretization
String Map
 
See Physics and Variables Selection.
equationform
String Map
 
See Physics and Variables Selection.
equationform_freq
String Map
 
See Physics and Variables Selection.
equationform_freq_src
String Map
 
See Physics and Variables Selection.
reconstructors
String Map
 
See Physics and Variables Selection.
useadvanceddisable
on | off
off
See Physics and Variables Selection.
Table 6-130: Properties for Values of Dependent Variables.
Property
Value
Default
Description
notlistsolnum
Vector of integers
[1]
Indices to selected solutions for values for variables not solved for.
notmanualsolnum
Vector of integers
[1]
Indices to solutions for values for variables not solved for.
notsolmethod
init | sol
init
Method for values for variables not solved for.
notsolnum
auto | all | first | last | from_list | interp | manual | positive integer
auto
Solution selection for values for variables not solved for.
notstudy
String
 
Reference to study or "zero" for zero solution.
nott
String
 
Specify time for interpolated solution of values for variables not solved for.
outputInterface
The interfaces to use as key
 
An output property for the physics interfaces in the output. It can be used as keys while setting the outputmap and outputselectionmap.
outputmap
String Map
 
See Store in Output for possible options and defaults (this property corresponds to the Output column). Possible values are physics, all, none, or selection.
outputselectionmap
String Map
 
A semicolon-separated string array of the output selections (specified with tags).
See setEntry() for information about setting the values for a property that uses a String Map. If you use the set(pname,value) method, you have to provide all alternating property name and property value pairs.
Table 6-131: Property for Mesh selection.
Property
Value
Default
Description
mesh
Vector of strings
 
Select meshes for geometries. The length of the vector is two times the number of geometries. Example value when two geometries geom1 and geom2 are available is: new String[]{"geom1","mesh1","geom2", "mesh2"}.