Pulse width research on half-sine excitation signal for bending vibrator

Abstract

Abstract Acoustic well logging adopts bending vibrators to transform high-voltage electric signals into acoustic signals. Excited acoustic signals have been proven best when the pulse widths are $0.5/{f_0}$ (${f_0}$ refers to the resonance frequencies of the bending vibrator). However, acoustic logging uses transformers to improve the excitation power, and these transformers change the rectangular excitation signals into similar half-sine signals. We study the relationships between the pulse widths of the similar half-sine excitation signals and the characteristics of the excited acoustic signals. Finite element analyses are performed to investigate the displacements of the center node on the surface of the piezoelectric ceramics that are excited by the pulse signals of different widths. Then, we design a circuit to realise the rectangular and half-sine excitation signals. Subsequently, acoustic experiments are carried out in our sound-deadening water tank to certify the simulation results. Results indicate that the best pulse width is $0.75/{f_0}$.