Large time-bandwidth product ultrasound generation by driving piezoelectric transducer

Based on the Mason equivalent circuit, a theoretical model of ultrasonic signal generated by controlling the excitation signal has been formulated. Large TBWP (time-bandwidth product) ultrasonic signals can be generated by driving a piezoelectric transducer with modified LFM (linear frequency modulation) signal. Better performances are obtained in the waveform, bandwidth and linear time-frequency relationship. Experimental results show that better axial resolution and higher power are achieved simultaneously. More than twice the amplitude of the echo from the bottom is received by the large TBWP signal over the conventional pulse-echo method, when detecting the layered structure with a high attenuation rubber block and a thin aluminum plate bonding together.