The periodically time-varying two-terminal network at a steady state may be described with a circular parametric operator. Within the domain of discrete time, such operator takes the form of a real element matrix. A circular parametric operator may be transformed into the frequency domain. In this version, the quantitative assessment of mixing and generating of harmonics of input and output signals is possible. This paper presents the derivation and effects of a genuine algorithm for identification of circular parametric operators. Some results of computer simulations are presented.

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The main subject of the paper is the description and determination of the impedance operator of a linear periodically timevarying (LPTV) one-port network in the steady-state. If the one-port network parameters and the supply vary periodically with the same period, the network reaches a periodic steady state. However, the sinusoidal supply may induce a nonsinusoidal voltage or current. It is impossible to describe such a phenomenon by means of one complex number. A periodically time-varying one-port network working in a steady-state regime can be described with a circular parametric operator. Within the domain of discrete time, such an operator takes the form of a matrix with real-valued entries. The circular parametric operator can be transformed into the frequency domain using a two-dimensional DFT. This description makes it possible to quantitatively assess LPTV system input and output harmonics aliasing. The paper also presents the derivation and the proof of convergence of an iteration scheme for the identification of circular parametric operators. The scheme may be used to determine the impedance of an LPTV one-port network. Some results of computer simulations are shown.

In this paper a new algorithm for periods determination of tasks implementation in the uniprocessor measuring and control system (MCS) node with elastic scheduling model is presented. Assigned solution means modification of frequency of all tasks. The level of modification depends on the scope of permissible periods changes, the tasks execution times and the tasks priority. Streszczenie. W artykule przedstawiono nowy algorytm doboru okresów realizacji zadań w jednoprocesorowym węźle systemu pomiarowosterującego z elastycznym modelem szeregowania zadań. Wyznaczone rozwiązanie oznacza modyfikację częstotliwości wykonywania wszystkich zadań jednak w różnym stopniu w zależności od zakresu dopuszczalnych zmian okresu wykonywania, czasu wykonywania zadania oraz jego priorytetu. (Algorytm doboru okresów realizacji zadań o różnym priorytecie w węźle pomiarowo sterującym).