We have also seen that real RHP zeros necessarily imply undershoot in the response to a step reference change. As might be expected, similar concepts apply to multivariable systems. This means that it is necessary to also account for the interactions between outputs rather than simply being able to focus on one output at a time. These issues will be explored below. Summary Analogous to the SISO case, MIMO performance specifications can generally not be addressed independently from another, since they are linked by a web of trade-offs.
MIMO systems are subject to the additional design specification of desired decoupling.
Alternatively, if dynamic decoupling is enforced, the constraint is dispersed over several channels.