  A number of techniques with different degrees of accuracies have been devised
for the measurement of acoustic wave attenuation in solids and liquids. Still,
a wide variation is observed in the attenuation values in different materials
reported in the literature. Present numerical study based on a 'propagating
wave' model analysis clearly shows that the attenuation constant obtained from
exponential fitting of the echo heights in pulse-echo method differs from the
exact value of intrinsic attenuation in the medium, even in the ideal situation
of plane wave propagation without diffraction, dispersion or scattering.
