The Operational Modal Analysis (OMA) technique is a methodology very often applied for the identification of dynamic systems when the input signal is unknown. The applied methodology is based on a technique to estimate the frequency response functions and extract the modal parameters using only the structural dynamic response data. without assuming the knowledge of the excitation forc... https://www.spidertattooz.com/NYX-Total-Control-Drop-Foundation-Brush-PROB22-p11165/