A novel approach was used for the on-line characterization of the stare of a fluidized bed. The treatment technique wing the Fast Fourier Transform of measured pressure fluctuations was developed to create plots describing the evolution of bed behavior from fixed bed to pneumatic transport. A new triad of quantities proposed are: divide ratio (degree of dominancy) of amplitude spectrum, square root of spectrum power of pressure sure fluctuations, and gas velocity. The technique was demonstrated on gas fluidization of solids having a wide size distribution composed of irregularly shaped solids.