Design of multisine excitations to characterize the nonlinear distortions during FRF-measurements

Multisine excitation signals are designed which will be used to detect and qualify the nonlinear distortions on frequency response function (FRF) measurements, and this without making additional experiments. The main idea in this method is to apply well chosen periodic excitations where not all harmonics are excited. The nonexcited frequency lines are used to detect, qualify and quantify the nonlinear distortions, while the FRF is measured at the same time at the excited harmonics. The selection of the multisine that will be used depends on the characteristics of the system that are studied. For that reason, not every multisine will produce in every case accurate, robust, and reliable results for every system. This paper presents some signals by which the following aims are accomplished: simplicity, robustness, and a reliable nonlinear characterization.