AC sweep
The AC sweep feature is a frequency analysis of a periodic system. It uses the steadystate determination algorithm to compute the transfer function of a periodic system at different frequencies of a userdefined frequency sweep range. For each frequency, the following steps are performed:
 apply the (sinusoidal) AC sweep perturbation (see figure below to add this component in the circuit) to the periodic system,
 determine the steadystate operation of this perturbed system,
 compute the system response at this perturbation frequency.
Important
The AC sweep perturbation device must be in the top level circuit. If it is placed in a subcircuit, Simba will send an error.
The perturbation frequencies are defined by specifying:
 the frequency sweep range with the start and the endfrequency,
 the sweep type: linear or logarithmic,
 the start and the endmagnitude of the sinusoidal perturbation,
 the number of points within this range.
Once executed, the transfer function between the perturbation signal S_p and the selected output variable S_o is then available in the Results tab. The transfer function is computed such as: 20 \log\left( S_o / S_p\right)
Important
The AC analysis on a range with low or very low frequencies should be carefully considered with the minimum time step which is set: it can lead to a very high number of points per period to be simulated for the steady state detection. For example, an analysis @10Hz with a minimum time step of 1e10s could lead to an analysis of 1e9 points.
Python API
The AC Sweep is entirely accessible from the Python API to automate transfer function analysis.
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