On parameter stability regions for several parameters using frequency response

The goals of this short paper are twofold. First, the parameter stability region, or the -decomposition technique as it is called in the Russian literature, for obtaining regions of stability in terms of one complex or two real parameters is shown to be applicable when certain elements of the system are given by numerical frequency response data. Second, a technique is presented for interpreting the parameter regions of stability obtained by the -decomposition method in a space of several parameters.