The paper presents a new method for experimental studies of typical prototypes with triple modal reservation. The authors propose to define the investigated devices in the frequency domain and then by using Advanced Design System software to redefine their characteristics in the time domain. The paper contains recommendations for the preparation and conduction of such experimental studies. Using these recommendations, the authors conducted measurements of the complex S-parameters of the circuits with triple modal reservation in the frequency range from 10 MHz to 18 GHz before and after failures. Then, to analyze the response to ultra-wideband interference, a pulse in the trapezoidal waveform with a duration of 150 ps was excited in Advanced Design System to the input of the reserved circuit. The maximum amplitude value at the end of the reserved circuit is obtained for all the faults studied. The authors also present the optimal order of switching the reserving circuits. This paper proposes the methods for analyzing the frequency and time characteristics. It makes possible to analyze the characteristics of circuits with multiple modal reservation and to determine the optimal switching order for reserving circuits. The proposed method requires commonly used equipment and a minimum set of technical tools that can reduce economic expenditures and time costs.