Communications, Audio: Frequencies higher than the human ear can hear, or higher than 20,000 Hz.

An electronic method of non destructive testing utilizing sound waves.

Pertaining to sound waves whose frequencies lie above the upper limit of audibility, i.e., above 20,000 cycles per second.

(adj.) (1) Sounds that the human ear cannot hear. (2) Of or relating to acoustic frequencies above the range that the human ear can hear, or above approximately 20,000 hertz.

a special machine used for the cleaning of medical

An Ultrasonic Cleaner is a device used by jewelers to clean jewelry using ultrasonic waves. This method loosens dirt most effectively, and small home units can also be found.

A cleaning machine for gemstones and jewelry that blasts dirt away with ultrasonic waves. But cannot be used on all types of gemstones such as pearls. Be sure to consult a professional jeweler before cleaning any jewelry.