Sun Surveillance, wireless solar powered video surveillance, glossary g

The Glossary

An all inclusive glossary of security lingo is provided for your convenience. This list
will undoubtedly be helpful when delving in to the realm of security.

G:

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.

Courtesy of CCTV Labs and CCTV focus magazine