A one-step procedure for frequency response estimation based on a Switch-Mode Transfer Function Analyzer

Frequency response analysis is a well established system identification method. In this paper, a simple and efficient method based on the classical Transfer Function Analyzer (TFA) technique is implemented for system identification. The novel algorithm has been called Switch-Mode-TFA. The originality of the proposed approach consists of: i) using a chirp TFA test input instead of a pure sine function, ii) using a variable sampling period instead of the traditional fixed sampling period and iii) a simplified implementation using switched electric circuits. The advantage of our approach is thus threefold: i) the frequency response of the system is obtained for the entire range of frequencies by means of only one identification test; ii) the number of samples per cycle remains constant, independent of the excited frequencies and iii) it can be easily implemented in hardware platforms. The results in both simulation and real-life examples indicate that the proposed Switch-Mode-TFA method can be reliably used for frequency response analysis in many other applications.