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
European cable television frequencies band. In most cable networks, the UHF band is unusable because its frequency is too high, so TV stations are only allocated within Band I, III, the Mid-, Super- and Hyperband. Even in modern cable networks, only some UHF channels (like only channels 21-26) may be usable. This leads to a high level of congestion in many European cable TV networks, especially as analogue transmission, which is still commonplace in cable television in Europe, is being migrated to digital transmission. European cable television frequencies These tables detail the frequencies used in European cable networks. Cable networks use frequencies which are