In this paper

the signal s strong non-stationary feature is demonstrated with time-frequency two-dimensional analysis by using the Wigner Distribution (WD) for pressure fluctuation signal in gas-solid fluidized beds. By a parameter defined as the Local Peak Weighted Average (LPWA) in WD space

the effect of velocity and probe height of fluidized beds on LPWA of pressure fluctuation is shown experimentally. The results indicate that the LPWA has much better reproducibility and accuracy than the major frequency of power spectral density in reflecting the properties of bubble phase.