A physical device for the measurement of weak harmonic distortions radiated from a piezoelectric rod

A physical device that promotes the acoustic radiation of the quadratic non-linear wave component from a piezoelectric element is designed, built and tested. The guiding model used to design the device, based on non-linear equivalent circuits for active and passive layers, is briefly recalled. Experimental signals where the second harmonic is the main component are shown. This work is expected to improve the accuracy of second harmonic component evaluation, in particular for NDE applications.