An ultrasonic generator was a device capable of creating a resonance frequency by means of acoustic energy. A covariant oscillator could be used as a makeshift ultrasonic generator. In 2371, when the Female Changeling was pretending to be Kira Nerys and trapped in rubble, she talked of a theft on Remmil VI where a band of Nausicaan raiders broke into the central museum by using an ultrasonic generator to create a sympathetic vibration in the webbing and shatter it. (DS9: "Heart of Stone")