A Virtual Instrument for Time-Frequency Analysis of Signals With Highly Nonstationary Instantaneous Frequency

This paper presents an open-source virtual instrument for time-frequency analysis. The purpose is to show the correct practical implementation, and the performance, of a number of complex algorithms and of a practical criterion (the concentration measure) to select the proper algorithm for a given signal. The virtual instrument provides efficient solutions for signals with a highly nonstationary instantaneous frequency. Despite variations of signal phase function, a high concentration can be achieved by a suitable choice of distribution form. The distribution can be chosen manually, or the instrument can perform optimal distribution selection. Namely, a procedure for the automated selection of optimal distribution order is provided. The concentration measure is employed as a selection criterion. A variety of options provides different comparisons for several distributions simultaneously. Efficiency of the proposed instrument is demonstrated on various examples. It is important to emphasize that an extensive and complex theory is implemented as a set of open-source algorithms. All the algorithms can be used “as is” or modified and upgraded (even separately) by researchers and practitioners in the field. The virtual instrument is available at http://www.tfsa.ac.me/Open_source_codes.html,, or upon request to the authors.