Application of rough set theory for NVNA phase reference uncertainty analysis in hybrid information system

The representation and processing of uncertainty knowledge are among the most commonly investigated problems in the rough set theory. In this paper, we apply the rough set theory to analyze the phase uncertainty of multi-tone stimulus scheme for nonlinear vector network analyzer (NVNA) phase reference frequency response in hybrid information system (HIS). Matlab was used to process the oscilloscope-based measured data for time and frequency response. The phase uncertainty experimental results revealed a significant correlation between the standard uncertainty and the response amplitude. Additionally, the lower amplitude in spectrum corresponded to higher phase uncertainty and vice versa. The proposed multi-tone stimulus scheme provides high resolution and rich intermodulation components around each harmonic for NVNA phase reference standard in HIS. The measured results were in good agreement with the theoretical formula-based results, and therefore, confirmed the validity of the proposed work.