U-Matic, 3/4U@Sony trademark. A professional Video Tape Recorder (VTR) which uses a 3/4" videocassette; term also used generically for this video format and various machines compatible with it. It incorporates two longitudinal audio channels (audio-1 and audio-2) which can be recorded separately; however their "Mix" audio output is monophonic. Channel 2 is typically used for recording SMPTE timecode. Some U-Matic models record "Address Track" timecode longitudinally in the same area of the tape as the helical video signal; this can eliminate the necessity of dedicating an audio track to timecode for video editing purposes. Nevertheless, either LTC or VITC timecode is still usually required in order to synchronize audio recorders and workstations. As other manufacturers offer video recorders and tape media which are compatible with the U-Matic standard, this popular industrial video format is also known generically as "3/4U".@Ultra-SCSI@A high-performance, 16-bit version of Wide SCSI, which is implemented via SCSI controller cards, installed in a computer's PCI expansion slots. Data transfers at up to 40 MB/second. See also SCSI, PCI, Fast SCSI, Wide SCSI.@Ultra-SCSI@A high-performance version of SCSI (see definition), announced in 1995 by a group of disk drive manufacturers, including Quantum, Seagate, and Hewlett-Packard. Ultra-SCSI is particularly suited for SCSI controller cards installed PCI expansion slots of a computer, as it supports "burst" transfer modes not only on the SCSI bus, but also on the computer's PCI bus itself. The advantage is that large data transfers (typical of digital audio and video) occupy less operating cycles of the computer's CPU, freeing it for other operations. Another advantage of Ultra-SCSI is that it is backwardly compatible with existing SCSI cables (both traditional 8-bit and 16-bit "wide"), standard SCSI connectors, operating systems and other software. See also SCSI, Fast SCSI, Wide SCSI.@Unbalanced Line@An audio line consisting of one signal-carrying conductor within a surrounding shield (outer conductor), which is also used as one of the audio signal wires; only these two wires are required. In contrast, a Balanced Line incorporates two signal-carrying wires, surround by a shield which does not carry any signal (a total of three wires). An unbalanced line is more susceptible to high-frequency loss and picking up electromagnetic interference than a Balanced Line, see definition.@Underscore@In film or video production, the music which provides a background, to provide a specific emotional atmosphere, or otherwise enhance a scene. See also Bed.@Unidirectional@Describes a microphone whose pickup pattern is more responsive in one direction than others, instead of being omnidirectional. The most common type is the Cardioid Microphone, see definition.@Unity Gain@In any signal processing device or other component in an audio signal path, the condition where the output level is exactly equal to the input level. Unity Gain is equivalent to a Gain Change of 0 dB. See also Gain.@UPC/EAN@Universal Product Code. Standardized method of identifying the catalog number of compact discs (and for machine-readable barcodes), this information is incorporated into the subcode area of the CD. See Red Book, Compact Disc.@UPS@Uninterruptible Power Supply. A device which monitors the incoming AC power (alternating current) used to supply computer or studio equipment, and immediately switches to its own internal battery backup power should the AC power fail. Usually, the UPS emits an audible signal (or in some cases triggers a message across a computer network)to alert users that they need to save their work, powering down their equipment within the time permitted by the unit's backup battery, to avoid losing data. Many LAN (local area network) servers, broadcast facilities, and digital audio editing facilities use UPS devices, in order to avoid data loss or corruption caused by improper shutdown of equipment when power failures occur. Many high-end UPS systems also supply AC power conditioning and voltage regulation.@USB@Universal Serial Bus. A type of connector used between personal computers and peripheral devices. Developed jointly by a coalition of manufacturers, USB supports a theoretical limit of up to 127 devices. Most importantly, these peripherals can be attached or removed with having to re-boot or reconfigure the computer. Newer Power Macintosh G3 models are using USB for keyboard and mouse connections, and since they also do not include a serial port, USB is the standard method of connecting MIDI interfaces to these machines. (You could also buy an optional serial port card, either for a PCI slot or the modem slot on these machines, if you must connect to an existing MIDI/SMPTE interface with a serial connection, but be SURE that the specific card you buy works with your software and hardware!) USB is also fast enough for two channels of digital audio - for example, Opcode's DATport and SONICport USB audio interfaces.@Utility@Specialized computer programs that perform relatively simple tasks, or which serve as auxiliary programs for the users of other, more complex computer applications.@
