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Frequency-response data model

Use `frd`

to create real-valued or complex-valued
frequency-response data models, or to convert dynamic system models to frequency-response data model
form.

Frequency-response data models store complex frequency response data with corresponding
frequency points. For example, a frequency-response data model *H*(*jw _{i}*), stores the frequency response at each input frequency

`frd`

model object can represent SISO or MIMO
frequency-response data models in continuous time or discrete time. For more information, see
Frequency Response Data (FRD) Models.You can also use `frd`

to create generalized frequency-response data
(`genfrd`

) models.

You can obtain `frd`

models in one of the following ways.

Create the model from frequency response data using the

`frd`

command. For example, you can create an`frd`

model with frequency response data taken at specific frequencies.For an example, see SISO Frequency-Response Data Model.

Convert a linear model such as an

`ss`

model into an`frd`

model by computing the frequency response of the model at specified frequencies.For an example, see Convert State-Space Model to Frequency-Response Data Model.

Estimate the model using offline frequency response estimation workflows. These workflows require Simulink

^{®}Control Design™ software.For more information, see Estimate Frequency Response at the Command Line (Simulink Control Design) and Estimate Frequency Response Using Model Linearizer (Simulink Control Design).

sets properties of the frequency-response data model using one or more name-value
arguments for any of the previous input-argument combinations.`sys`

= frd(___,`Name,Value`

)

interprets frequencies in the units specified by `sys`

= frd(`ltiSys`

,`frequency`

,FrequencyUnits)`FrequencyUnit`

.

The following lists contain a representative subset of the functions you can use with
`frd`

models. In general, many functions applicable to Dynamic System Models are also
applicable to a `frd`

object. `frd`

models do not work with
any time-domain analysis functions.