This entry contributed by Dana Romero
Ultrasonic frequencies are frequencies of sound energy higher than the upper limit of the human hearing range, about 20 kHz. With the exception of surface acoustic wave (SAW) devices (which operate at frequencies higher than 100 MHz), most common ultrasonic devices operate at frequencies well below 1 MHz because of increasing attenuation at higher frequency.
Some of the most notable uses of ultrasonic frequencies are sonar, ultrasonic welding, ultrasonic cleaning, nondestructive testing (e.g., sound reflected by cracks, bubbles, or poorly bonded layers), medical sonograms, and sounds used by animals such as bats in their version of sonar.
Acoustics, Hearing Range, Sonar, Sonics, Ultrasound
