How can I create a Bode Diagram of a dynamic model?

Dynamic Simulation

In order to create a Bode diagram you will need to use the Model Frequency Response command (ComFreqresp). This command is described within the User manual, section "Frequency Response Analysis", Chapter "RMS/EMT Simulations". 

Attached you can find a pre-configured example in which a simple second order Band pass filter with poles at 4 and 14 hz is being analysed. The center frequency of the filter is given by sqrt(4*14)=7.48 Hz. Import/activate the project and execute (as pre-configured in the example) the Frequency response analysis command. The Bode diagram of the transfer function of this filter is obtained, as shown in the attached image (snapshot.png). The center frequency is confirmed to be about 7.5 Hz, as expected.

Note that the frequency response analysis works well if operated within a limited frequency range and for small test signals that excite the dynamic model. The assumption here is that the dynamic model operates as a linear, time continuous model within the operating region in which it has been setup. Whenever the amplitude of the excitation signal is too high (or the frequency range is too broad) the frequency response analysis might generate incorrect results.


Whenever sharp peaks are existing in the amplitude diagram of the Bode Plot, there exists the risk of obtaining noisy results. Noise in the Bode Diagram may be slightly removed by adjusting the "Damping Factor" parameter of the "Calculation of Initial Conditions" command, page "Solver Options". Refer to the following FAQ for further information on the "Damping Factor" parameter: .