Complex modal statistics in a reverberant dissipative body

The statistics of the ultrasonic resonance peaks of a finite elastic body are investigated. The distribution of peak phases, and the normalized variance of peak amplitudes, are shown to be consistent with a hypothesis that the modes themselves are complex Gaussian random numbers. A value q = 0.33 for the ratio of the standard deviations of the imaginary and real parts of the modes is found to fit the data, and to bring recent theory of power variances into better accord with measurements. (C) 2000 Acoustical Society of America.