pexcit
Level of excitation of input signals
Syntax
Ped = pexcit(Data)
Ped = pexcit(Data,Maxnr)
Ped = pexcit(Data,Maxnr,Threshold)
Ped = pexcit(Data,Maxnr,Threshold,Maxsize)
[Ped,Maxnr] = pexcit(___)
[___] = pexcit(___,Name,Value)
Description
Ped = pexcit(Data) tests the degree of persistence of excitation
for the input.
Data can contain time-domain or frequency-domain input/output
data, and can be in the form of a timetable, a comma-separated pair of numeric matrices, or an iddata object. If there are multiple experiments,
data can be a cell array.
Ped is the degree or order of excitation of the inputs in
Data and is a row vector of integers with as many components as
there are inputs in Data. The intuitive interpretation of the degree
of excitation in an input is the order of a model that the input is capable of
estimating in an unambiguous way.
Ped = pexcit(Data,Maxnr) uses Maxnr to specify
the maximum order tested. Default value of Maxnr is
min(N/3,50), where N is the number of data
samples in the input data.
Ped = pexcit(Data,Maxnr,Threshold) uses
Threshold to specify the threshold level of the singular values
of the input covariance matrix. Default value of Threshold is
1e-9. Set Maxnr to [], to
allow its value to be automatically determined by the software.
Ped = pexcit(Data,Maxnr,Threshold,Maxsize) uses
Maxsize to specify the limit for the size of any matrix formed.
Default value of Maxsize is 250000. Set
Maxnr and Threshold to [],
to allow their values to be automatically determined by the software.
[Ped,Maxnr] = pexcit(___) returns the value of
Maxnr used.
[___] = pexcit(___,
uses additional model options specified by one or more name-value arguments. Name,Value)
The available arguments consist of InputName and
OutputName, which are the input and output channel names. Use
these arguments especially when data is a timetable that has more
variables than you want to use. Also use OutputName to identify the
output channels when the timetable data contains more than one
output variable. Otherwise, the software interprets only the last variable as an output
channel.
For example, specify the input and output signal variable names using sys =
pexcit(data,'InputName',["u1","u3"],'OutputName',"y1").
References
Section 13.2 in Ljung (1999).
Version History
Introduced before R2006a
See Also
advice | iddata | checkFeedback | idnlarx
