Siemens CRT, TFT manual Secam

Glossary

SECAM

Sequential Couleur A'Memorie, a colour television system used in France and few other countries.

Sensitivity of a Camera

Is the minimum light level required at the CCD chip which will gener- ate a usable video picture. It is measured in lux.

Sequential Switcher

A type of switcher that allows multiple cameras to be displayed or recorded in full screen one at a time.

Shield

Is a copper braid which covers the dielectric and centre core of a coaxial cable. It protects the video signal from EMI.

Signal Loss

Is a reduction in signal strength expressed in decibels.

Signal to Noise Ratio

It is the ratio between the signal voltage and the noise voltage gen- erated by an electronic circuit. It is measured in decibels (db).

Simplex

A description of a system which can handle only one channel of vid- eo, audio or data signal. In CCTV the term is used for multiplexers, where only one function can be performed eg recording multiplexed images, but displaying only in full screen.

Single Mode Cable

An expensive type of fibre optic cable with a narrow glass core which allows only a single path for signal transmission.

Silicon Wafer

Is a semiconductor material on which the CCD chips are etched.

Snow

Appears as small dots on the monitor and is caused by noise in the video signal.

Sodium Vapour Lamp

Is an artificial light source which is very efficient and uses sodium vapour to produce a yellow-orange light.

Spectral Response

Is the sensitivity of a device to different light frequencies.

Standard Angle Lens

This type of lens which provides a view which has the same propor- tions as seen by the human eye. It has a magnification ration of 1.

Step Down Transformer

This transformer is used in power supplies to step down or lower the main line voltage. The ratio between the number of turns of the pri- mary coil to the secondary coil determines the step down voltage.

Stranded Cable

A type of cable in which a number of wires enclosed in an outer jacket are used to transmit the electrical signal.

Sunshield

A movable accessory placed on top of outdoor housings to prevent direct light falling on the camera.

Sync Generator

Is a device which generates sync pulses which are then used to syn- chronise cameras.

Synchronisation

A process which ensures that the formation of frames in a multi cam- era system start at the same time. There are different ways to achieve camera synchronisation.

Synchronous data transmission

Stands for a transmission technique that uses a control line to trans- mit control bits for correct transmission.

Telephoto Lens

This type of lens can be used to view far away objects. It has a mag- nification ration >1.

Terminal Strip

Screw connection for interconnecting cables, various current ratings.

Test Pattern Generator

A device which generates a test pattern to be used to adjust and test a CCTV monitor.

Thermal Paper

Is a special type of paper used in video printers.

Time Based Switching

Is a feature in matrix switchers which allows various programmed camera sequences to be initiated at various times.

Time Lapse VCR

A type of video cassette recorder especially designed for CCTV. It allows more recording time on a single video tape by not recording all the frames.

Time/Date Generator

A device which generates time and date and superimposes it on the video signal.

Touch Screen

Is a type of modern monitor screen. Action can be initiated by touch- ing the relevant point on the monitor screen. Sometimes referred to as a GUI (Graphical User Interface).

Trapezoidal Distortion

Is a type of distortion in the monitor caused due to non uniform scan- ning which makes the scanning lines look wider at the top than at the bottom of the monitor.

Triaxial Cable

Is a type of coaxial cable which has two layers of shield to provide bet- ter protection against EMI.

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