5.5 The Singular-Value Plot
For MIMO systems, BodePlot returns a total of individual Bode plots, and consequently, the amount of information quickly grows with the number of inputs and outputs . SingularValuePlot provides a means to generalize this information by generating a plot of the frequency dependence of singular values of the transfer matrix evaluated at different values of (or for discrete-time systems, being the sampling period).
Creating the singular-value plots.
Here is a mixing tank system (see Section 10.1).
This plots the frequency dependence of the singular values.