  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.
