The formulation allows the designer to explicitly
define the weighting matrices such that the process
response at a certain frequency is penalized the most,
thereby concentrating the control effort on that particular
frequency. Unfortunately, Equation (3) is not readily
solved in its current form due to the frequency
dependency. It was shown by Gupta that by utilizing
Parseval’s theorem, the cost function in Equation (3)
can be interpreted as a problem of minimizing suitably