Complex modal statistics in a reverberant dissipative body

The statistics of the ultrasonic resonance peaks of a finite elastic body a re investigated. The distribution of peak phases, and the normalized varian ce of peak amplitudes, are shown to be consistent with a hypothesis that th e 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 varian ces into better accord with measurements. (C) 2000 Acoustical Society of Am erica. [S0001-4966(00)03110-6].