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Supported Data Transformations

The following table shows the different ways you can transform data from one data domain to another. If the transformation is supported for a given row and column combination in the table, the command used by the software is listed in the cell at their intersection.

Original Data FormatTo Time-Domain Data
(iddata object)
To Frequency-Domain Data
(iddata object)
To Frequency-Response Data
(idfrd object)
Time-Domain Data
(iddata object)
N/AUse fft
  • Use etfe, spa, or spafdr.

  • Estimate a linear parametric model from the iddata object, and use idfrd to compute frequency-response data.

Frequency-Domain Data
(iddata object)
Use ifft (works only for evenly spaced frequency-domain data).N/A
  • Use etfe, spa, or spafdr.

  • Estimate a linear parametric model from the iddata object, and use idfrd to compute frequency-response data.

Frequency-Response Data
(idfrd object)
Not supportedUse iddata. The software creates a frequency-domain iddata object that has the same ratio between output and input as the original idfrd object frequency-response data.
  • Use spafdr. The software calculates frequency-response data with a different resolution (number and spacing of frequencies) than the original data.

Transforming from time-domain or frequency-domain data to frequency-response data is equivalent to creating a frequency-response model from the data. For more information, see Frequency-Response Models.

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