Estimation of non linear attenuation using frequency agility processing

A technique is developed to estimate frequency-dependent attenuation in reflection which does not depend on a prior knowledge of the linearity property of the attenuation. It is accepted that attenuation increases linearly with frequency for normal soft tissue but is more generally described by alpha (f)= beta f/sup /n. The author expands on a time-domain procedure introduced recently to cases of nonlinear frequency attenuation by estimating beta and n using a frequency agility technique. The predicted variance is comparable to frequency-domain methods while simultaneously estimating an additional parameter and not being restricted to linear cases. Experimental results are compared to theoretical predictions.<>