A signal analysis method based on reassigned scalogram

The acoustic signal of a mechanical watch movement consists of many modal frequencies of its escapement. However, the traditional methods neglected such valuable information which is in frequency domain. This paper presents a method for the signature analysis of mechanical watch movements by combining reassigned scalogram with finite element analysis (FEA). First, reassigned scalogram is applied to reveal the frequency components in different shocks by mapping the signal into a 2D domain of time and frequency. Then, FEA is introduced to find the modal frequencies of the mechanical watch movements. By comparing the frequencies obtained by two ways, the mechanical watch movement is easier to analyze and therefore to diagnose possible malfunctions robustly.