Method for detecting transverse mode vibrations in an ultrasonic hand piece having a blade

摘要

A method for detecting transverse mode vibrations in an ultrasonic hand piece/blade for determining the existence of unwanted vibration in the hand piece/blade. A tracking filter centered at the drive frequency of the generator, is used to monitor the drive frequency of the ultrasonic generator and attenuate the drive signal when it exceeds a predetermined level. The tracking filter has a wide pass band. Alternatively, a tracking filter having a pass band which is divided into several regions is used to avoid other longitudinal resonances, such as a resonance at a second harmonic, or other spectral features that would otherwise detract from the tracking accuracy of the filter.