A test for determining systems with “mixed” small gain and passivity properties

“Mixedness” is a property that captures elements of the notions of passivity and small gain. In the frequency domain, a linear, time-invariant system is called “mixed” if, over some frequency bands, it is strictly passive and, over the remaining frequencies, it has a gain of less than one; there exist no frequencies over which the system has neither of the notions of these properties associated with it. In this paper, a test is developed for determining whether or not a linear, time-invariant system is “mixed”.