Estimate Frequency Response with Linearization-Based Input Using Linear Analysis Tool

This example shows how to perform frequency response estimation for a model using the Linear Analysis Tool. The input signal used for estimation is based on the linearization of the model.

Linearize Simulink model.

  1. Open Simulink® model.

    sys = 'scdDCMotor';
  2. In the Simulink Editor, select Analysis > Control Design > Linear Analysis.

  3. Linearize the model using the model initial conditions as the operating point.

    In the Linear Analysis tab, click Bode.

    A new linearized model, linsys1, appears in the Linear Analysis Workspace.

Create sinestream input signal.

  1. In the Estimation tab, in the Input Signal drop-down list, select Sinestream.

  2. Initialize the input signal frequencies and parameters based on linsys1.

    In the Create sinestream input dialog box, click Initialize frequencies and parameters.

    The Frequency content viewer is populated with frequency points. The software chooses the frequencies and input signal parameters automatically based on the dynamics of linsys1.

  3. In the Frequency content viewer, select all the frequency points.

  4. Specify the amplitude of the input signal.

    Enter 1 in the Amplitude box.

  5. Create the input sinestream signal.

    Click OK. The input signal in_sine1 appears in the Linear Analysis Workspace.

Estimate the frequency response.

Click Bode Plot 1 to estimate the frequency response.

The estimated system, estsys1, appears in the Linear Analysis Workspace and the its frequency response is added to Bode Plot 1.

The frequency response for the estimated model matches that of the linearized model.

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