Transducer excitation with switched-mode encoded signals for harmonic and amplitude control verified using the Leach model

Abstract

An excitation method to reduce harmonic content in the third harmonic was verified utilizing SPICE modeling. The SPICE model incorporated a MOSFET model and the Leach model to form a multi-level switch-mode pulser circuit. The pulser circuit was driven with a Harmonic Reduction PWM excitation sequence and a stepped excitation sequence with a fundamental frequency of 2 Mhz. An FFT of the excitation sequences was compared to verify the performance of the MOSFETs with the excitation sequences. It was found that at the third harmonic, the harmonic content was reduced by 22.2 dB.