Pulsed Response of Focused Arrays in Echographic B-Mode Systems

The transient response of a focused array in echographic systems for imaging in medical and nondestructive evaluation applica- tions is obtained in an analytic form. The results constitute an extension of the response to a monochromatic excitation. The actual shapes of the pulses used are explicitly accounted for by means of suitable parame- ters, as the resonance frequency and the damping factor of the trans- ducers. The one- and two-way responses are evaluated through the use of the linear system theory and complex envelopes for the involved sig- nals. Gaussian-shaped envelopes, which fit most practical situations at a satisfactory amount, are considered for the pulses. Simple expres- sions in a closed form directly relate the response to the system param- eters.