LFT uncertain model validation with time and frequency domain measurements

We study a model validation problem pertaining to linear fractional transform (LFT) uncertainty models. We extend previous validation approaches, based upon either time or frequency measurements, to one using simultaneously time and frequency domain data. We show that this problem can be reduced to two independent convex feasibility tests, each of which corresponds to the time or frequency domain data alone, and each can be verified numerically using available algorithms and software programs. The merit of such a mixed time and frequency domain approach, therefore, lies in that not only can it accommodate the two distinctively different types of measurement data simultaneously, but also from a computational standpoint it will not suffer from a complexity growth beyond that associated with the existing time domain tests.