On Sep 2, 2006, at 7:51 AM, graywolf wrote: > Supersonic means just above the human hearing range, ultrasonic means > far above it but below the range of radio waves. Usually that is > something like 15kc to 30kc for supersonic, and 30kc to 100kc for > ultrasonic waves. It is the frequency that is important to the label, > not the media. Note that the terms are used differently when used for > aircraft rather than electronics.
That's rather imprecise. The dictionary defines "supersonic" and "ultrasonic" as meaning: --- ultrasonic adjective of or involving sound waves with a frequency above the upper limit of human hearing. supersonic adjective involving or denoting a speed greater than that of sound. --- These adjectives do not change meaning in the context of aircraft or electronics, or anything else, and they do not compete with one another. If you go to http://www.dictionary.com and look them up, you'll see quotations from 5-8 credible dictionary sources, only one of which suggests the kind of tiering you allude as a possible alternative definition to ultrasonic. Godfrey -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net
