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Guide to Closed Circuit TV (CCTV)

So would you like to play "Spot the CCTV Camera?". Eagle eyed visitors may recognise the profusion of street furniture, surrounding a single heritage dome camera keeping watch over part  of Londons' prestigious Oxford Street shopping area.

If you need to handle
multiple images ....

Ten 'Must Know' things about Multiplexers

1) Like a computer, the speed of the multiplexers image sampling circuitry, will dictate how many images per second can be captured (the more images /sec, the less 'stepped' the movement looks in each individual channel).

2) Most multiplexers can display images from a single camera or using a top end model, a mosaic of up to 32 individual camera pictures

3) With most ‘Duplex’ multiplexers, picture quality is noticeably improved in a ‘Live’ mosaic, rather than a 'VCR' output mosaic.

4) At present, a very limited number of multiplexers can be ‘hot linked’ to a Digital Video Recorder, using a high resolution 'digital' signal connection.

5) Most multiplexers offer ‘Loop through’ video connectors on the back, so camera signals can also be linked to secondary display equipment (such as switchers, quad etc.).

6) Although multiplexers can form the pivotal hub of a large CCTV system, without backup, they can also be the weakest link..

7) Some of the more advanced units on the market, also offer sophisticated motion detection functions as standard.

8) Some multiplexers include ‘Video Loss Alarm’ circuits, so if a camera fails or is disabled, an indicator + alarm will go off.

9) With a few “TRIPLEX’ units, it is possible to display video playback, and live images on the same screen, whilst recording at the same time

10) Using two identical multiplexers, it is usually possible to transmit a large number of images down a single communication link (cable, fibre optic etc.) and then reconstitute the individual signals at the other end ... very cost effective!!

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