Spectrogram and PQ-Plot Based Chaotic Signals Analyses

Chaotic signals’ complexities feature the disorder state between the order and stochastic states. The time-frequency analyses will increase the representation power with the help of pq-plot in 0-1 test for chaos. This simulation work tested three equations of Logistic, Li and Chua under two methods of spectrogram and pq-plot. Three window-bands of spectrogram are selected in wide band of 128, trade-off of 512 and narrow of 2048. Three values of the chaos-sensing-factor c in pq-plots are used with 1.0456, 1 and 0.75. The simulation results show that (1) narrow band was fitted for three equations in spectrogram, (2) the evolutions of Li chaos equation met the raised power of frequency bands, and (3) compared with three cases under test, chaos-sensing-factor c in pq-plots was slightly dropped. The conclusions grasped the chaos recognition tools of both spectrogram and pq-plot of 0-1 test for chaos in digging out the visualization of time-frequency-energy-dynamics analyses.