You can estimate both continuous-time or discrete-time grey-box
models for data with the following characteristics:
Time-domain or frequency-domain data, including time-series
data with no inputs.
Nonlinear grey-box models support only time-domain data.
Single-output or multiple-output data
You must first import your data into the MATLAB® workspace.
You must represent your data as an iddata or idfrd object. For more information about
preparing data for identification, see Data Preparation.