Generic Tracking Specifications Translation from Time Domain to   Frequency Domain
  In certain types of robust control techniques, it is common having to deal with control problems where the specifications, described in the time domain, need to be translated to the frequency domain. This usually happens in techniques, such as Quantitative Feedback Theory, where the control problem is developed in the frequency domain. Therefore, not only process plants and disturbances should be specified in this domain, but also the limits and restrictions initially imposed in time. The question is important if we consider that any deviation in the parameters transfer from one domain to another will decisively influence in the development of the problem and, above all, in the finally result expressed in temporal terms. The technique presented allows the translation of the upper frequency limit in generic tracking specifications from time domain to frequency domain accurately. It will use approaches based on 2nd order systems or an envelope approach based on higher order systems. 
Javier Joglar-Alcubilla
cs.SY