Acoustic microscopy acoustic microscope (CSAM), and C-mode scanning acoustic microscope (C-SAM). More recently acoustic microscopes based around picosecond ultrasonics systems have demonstrated acoustic imaging in cells using sub-optical wavelengths working with ultrasonic frequencies into the multi-GHz. Since the vast majority of acoustic microscopes in use today are C-SAM type instruments, this discussion will be limited to these instruments. Ultrasound is broadly defined as any sound having a frequency above 20 kHz, which is approximately the highest frequency that can be detected by the human ear. However, the acoustic microscopes emit ultrasound ranging from 5 MHz to beyond 400 MHz so that micrometre
6955 kHz 6955 kHz "6955 kHz" is the sixth episode of the third season of the American science fiction drama television series "Fringe". It first aired on November 11, 2010 in the United States. The third season spent much of its time alternating between the prime and parallel universes, and "6955 kHz" was set in the former. The storyline followed the Fringe team's investigation into a numbers station that mysteriously gave its listeners amnesia, a case that ultimately ties to a doomsday device. The episode was written by story editors Robert Chiappetta and Glen Whitman, and was directed by Joe Chappelle. Its