U: (1) Colour difference signal used in PAL. (B—Y) reduced in amplitude and bandwidth limited to about 1.2 MHz. U = 0.493 (B—Y). (2) Rackheight unit. A measure of the height of equipment racks, where 1 U = 44.5 mm (1.75 inch).
U-format: The video cassette format using 19 mm (¾ inch) tape compatible with the U-matic system.
ultra high frequency (UHF): The region of the electromagnetic spectrum between 300 MHz and 3000 MHz. See Appendix N .
ultra low frequency (ULF): The region of the electromagnetic ...