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
Charles Samuel Franklin from this site in 1936. Franklin received the 1922 IRE Morris N. Liebmann Memorial Award "for his investigations of short wave directional transmission and reception". Franklin received British patent 242342 in 1924 for "a pronounced directional effect from aerials of the type that are electrically long in comparison with the signal wavelength". Alas, this antenna is so physically tall (about 1,813 feet at 540 kHz, and about 612 feet at 1600 kHz) that its use is generally restricted to frequencies of 1400 kHz and above, with one example at 1500 kHz (KSTP, St. Paul, MN, non-directional, daytime only) and two