Cascadia Digital video recorder Manual de usuario descargar pdf (Pagina 15)

CCTV Glossary

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Gain - Any increase or decrease in strength of an electrical signal. Gain is measured in terms of

decibels or number of times of magnification.

Gamma - A correction of the linear response of a camera in order to compensate for the monitor

phosphor screen nonlinear response. It is measured with the exponential value of the curve

describing the non-linearity. A typical monochrome monitor’s gamma is 2.2, and a camera needs

to be set to the inverse value of 2.2 (which is 0.45) for the overall system to respond linearly (i.e.,

unity).

Gamut - The range of voltages allowed for a video signal, or a component of a video signal.

Signal voltages outside of the range (i.e., exceeding the gamut) may lead to clipping, crosstalk or

other distortions.

Gen-lock - A way of locking the video signal of a camera to an external generator of

synchronization pulses.

GHz - GigaHertz. One billion cycles per second.

GB - Gigabyte. Unit of computer memory consisting of about one thousand million bytes (a

thousand megabytes). Actual value is 1,073,741,824 bytes.

GND - Ground (electrical).

Gray scale - A series of tones that range from true black to true white, usually expressed in 10

steps.

Ground loop - An unwanted interference in the copper electrical signal transmissions with

shielded cable, which is a result of ground currents when the system has more than one ground.

For example, in CCTV, when we have a different earthing resistance at the camera, and the

switcher or monitor end. The induced electrical noise generated by the surrounding electrical

equipment (including mains) does not discharge equally through the two earthings (since they are

different) and the induced noise shows up on the monitors as interference.

GUI - Graphical user interface.

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Cascadia Digital video recorder Manual de usuario Pagina 15