A signal processing tool to compute and visualize the Choi–Williams distribution and the Hilbert–Huang transform of nonstationary signals in fusion research

This article describes the implementation of the Choi–Williams distribution (CWD) and the Hilbert–Huang transform (HHT) in an integrated signal processing and visualization tool, with emphasis on the techniques used to speed up the calculations. The new tool, which has been specifically designed for the time–frequency analysis of nonstationary signals in fusion research, allows full control of the calculations and immediate visualization of the results through an interactive graphical user interface (GUI).