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
Australian and New Zealand television frequencies allocation issue was not fixed until the late 1990s, when the FM band was expanded to the standard full 20 MHz block. As of the mid-2010s NZ totally abandoned its VHF band for UHF channels above 25. There is a frequency offset for many DTV channels between Australia and NZ, because of historical reasons relating to the introduction of PAL. DVB-T channel allocation note Table notes : Text in "italics" means these frequencies are not currently used but set aside as a Guardband or for future use. The ABC has the highest number of transmission sites: often, but not always,