Dictionary of Technical Terms - O
one-shot (monostable multivibrator)
A circuit that produces an output signal of fixed duration when an input signal of any duration is applied. Setting edit points while VTRs are rolling. A non-precision method of editing similar to live video switching. Edit that has a start time but no designated out-point. An edit that runs until stopped by the operator. The program (software or firmware) that controls a computer's functions. An optical fiber with a high refractive index clad with a material having a lower index of refraction. A coupling device consisting of a light emitter and a photodetector used to couple signals without any electrical connection. Used for voltage and noise isolation between input and output while transfer- ring the desired signal. A transform which causes an object to move in a circle around a point on the X-Y grid. Diodes arranged in such a way as to construct an OR gate. Sampling of a line of repetitive video signal in such a way that samples in each line are in the same horizontal position. An electronic device that generates alternating-current at a frequency determined by the values of the components in its circuits. Open systems interconnection. Originating service office. Optical time domain reflectometer. A device that tests losses in optical fiber. An edit out-point. The first frame that is not recorded (after the end of an edit). Edit out-point timing. The current, voltage, power, or driving force delivered by a circuit or device. The impedance a device presents to its load. The impedance measured at the output terminals of a transducer with the load disconnected and all impressed driving forces taken as zero. See return loss. In electronic equipment, the final stage that produces the finished output signal(s). The ratio of attenuation provided by the output stage to an interfering signal driving one output compared to a second output. The ratio is measured at the second output. A good specification protects output signals against incorrect cabling, such as accidental untermination or double termination. A remote broadcast, typically from a remote truck.ovenized crystal oscillator (OXO)
A crystal oscillator that is surrounded by a temperature regulated heater (oven) to maintain a stable frequency in spite of external temperature variations. 1. In audio or video, a signal that is superimposed over a second signal. Also called voice over in audio. 2. In video switchers, a selection that determines which key layer appears on top of the other key layer in a mix/effects. A video monitor condition in which the raster extends slightly beyond the physical edges of the CRT screen, cutting off the outer edges of the picture. The first maximum excursion of a pulse beyond the 100% level. That portion of a pulse that exceeds its defined level temporarily before settling to the correct level. Overshoot amplitude is expressed as a percentage of the defined level. See also ringing.
