The main objective of this project is to develop a new measurement procedure and to construct a modular measurement system for determination of complex material parameters that are used in ultrasound (US) systems which are working in the nonlinear conditions. The materials' parameters in existing US systems used in biomedicine and industry are determined at low excitation levels assuming linear physical principles and consistent thermodynamical conditions. This is different from real operating conditions where range of applied powers and types of excitation signals is various and very often far away from linear. The neglect of these nonlinearities in active and passive materials, used in the complete US system construction process, leads to the problem of the US systems’ efficiency factor in the nonlinear driving conditions. The construction of modular measurement system with included and modified interferometry and time of flight principle with added new measurement procedure is crucial for developing novel US systems with higher electroacoustic efficiency factors. The new method is based on tracking the resonant frequency changes of the nonlinear electro-mechanical-acoustical system for determination complex material parameters. The new modular measurement system will enable exposure of materials to the US fields with various driving conditions. Tracking the resonant frequency changes of excitated loading medium sample (active piezoceramic or passive construction elements or different types of loading mediums) will be a novel method for determination of material parameters when nonlinear effects appear in the loading mediums. As a result of more precise constructive material parameters determination, prototypes of US systems with probes and electronic excitation circuits for applications in biomedicine and industry, with obtained higher electroacoustic efficiency factors will be developed, constructed and tested during this project.