The Transfer Function Analyzer revisited

Frequency response analysis is a well established system identification method. In this paper, a novel frequency domain method based on the classical Transfer Function Analyzer (TFA) technique is implemented for the identification of three systems: i) a mass-spring-damper system; ii) a human respiratory impedance; and iii) the yaw movement of an unmanned aerial vehicle (UAV). The novel technique has been called Chirp-TFA. The originality of the proposed approach consists in: i) using a chirp TFA test input instead of a pure sine function, and ii) using a variable sampling period instead of the traditional fixed sampling period. The advantage of our approach is thus twofold: i) the frequency response of the system is obtained for the entire range of frequencies by means of only one identification test and ii) the number of samples per cycle remains constant, independent of the excited frequencies. The results indicate that the proposed Chirp-TFA method can be reliably used for frequency response analysis in many real-life applications.