Acoustic Sensors

Acoustic Sensors include those that use sound as a sensing medium. Doppler techniques allow the measurement of velocities. Ultrasound often provides more information about mechanical machinery vibrations, fluid leakage, and impending equipment faults than do other techniques. Sonar uses sound to determine distance using time-of-flight information. It is effective in media other than air, including

underwater. Caution should be used in that the propagation speed of acoustic signals depends on the medium. The speed of sound at sea level in a standard atmosphere is cs=340.294 m/s. Subterranean echoes from earthquakes and tremors can be used to glean information about the earth’s core as well as about the tremor event, but deconvolution techniques must be used to remove echo phenomena and to compensate for uncertain propagation speeds. membraneDrive electrodesDetector electrodesmembraneDrive