Transfer function estimation
sys = tfest(data,np)
sys = tfest(data,np,nz)
sys = tfest(data,np,nz,iodelay)
sys = tfest(___,Name,Value)
sys = tfest(data,init_sys)
sys = tfest(___,opt)
estimates
a continuoustime transfer function, sys
= tfest(data
,np
)sys
,
using time or frequencydomain data, data
, and
contains np
poles. The number of zeros in the sys
is max(np1,0)
.
estimates
a transfer function containing sys
= tfest(data
,np
,nz
)nz
zeros.
estimates
a transfer function with transport delay for input/output pairs sys
= tfest(data
,np
,nz
,iodelay
)iodelay
.
uses
additional options specified by one or more sys
= tfest(___,Name,Value
)Name,Value
pair
arguments. All input arguments described for previous syntaxes also
apply here.
uses
the dynamic system sys
= tfest(data
,init_sys
)init_sys
to configure the
initial parameterization of sys
.
specifies
the estimation behavior using the option set sys
= tfest(___,opt
)opt
.
All input arguments described for previous syntaxes also apply here.

Estimation data. For time domain estimation, Timeseries models, which are models that contain no measured
inputs, cannot be estimated using For frequency domain estimation,
For multiexperiment data, the sample times and intersample behavior of all the experiments must match. 

Number of poles in the estimated transfer function.
For systems that are multipleinput, or multipleoutput, or both:


Number of zeros in the estimated transfer function.
For systems that are multipleinput, or multipleoutput, or both:
For a continuoustime model, estimated using discretetime data,
set 

Transport delay. For continuoustime systems, specify transport delays in the
time unit stored in the For a MIMO system with ny outputs and nu inputs,
set The specified values are treated as fixed delays.
Use 

Estimation options.


Dynamic system that configures the initial parameterization
of If Use the To specify an initial guess for, say, the numerator of To specify constraints for, say, the numerator of
You can similarly specify the initial guess and constraints for the denominator and transport lag. If 
Specify optional commaseparated pairs of Name,Value
arguments.
Name
is the argument
name and Value
is the corresponding
value. Name
must appear
inside single quotes (' '
).
You can specify several name and value pair
arguments in any order as Name1,Value1,...,NameN,ValueN
.

Sample time. Use the following values for
Default: 

Input delay for each input channel, specified as a scalar value
or numeric vector. For continuoustime systems, specify input delays
in the time unit stored in the For a system with You can also set Default: 0 

Feedthrough for discretetime transfer function. Must be a NybyNu logical matrix. Use a scalar to specify a common value across all channels. A discretetime model with 2 poles and 3 zeros takes the following form: $$H{z}^{1}=\frac{b0+b1{z}^{1}+b2{z}^{2}+b3{z}^{3}}{1+a1{z}^{1}+a2{z}^{2}}$$ When the model has direct feedthrough, Default: 

Identified transfer function.

[1] Garnier, H., M. Mensler, and A. Richard. "Continuoustime Model Identification From Sampled Data: Implementation Issues and Performance Evaluation." International Journal of Control, 2003, Vol. 76, Issue 13, pp 1337–1357.
[2] Ljung, L. "Experiments With Identification of ContinuousTime Models." Proceedings of the 15th IFAC Symposium on System Identification. 2009.
[3] Young, P. C. and A.J. Jakeman. "Refined instrumental variable methods of timeseries analysis: Part III, extensions." International Journal of Control 31, 1980, pp 741–764.