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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 ....

Display Multiplexers

Although PIP and Quad units are technically display multiplexers, this terminoligy is normally reserved for larger capacity units capable of accepting eight, sixteen, or even more cameras.

When multiplexers were first introduced some years ago, it was not unusual to find a unit designed specifically as a display only multiplexer, capable of splitting the screen up into various mosaics of images.

This would give the option of displaying a number of cameras; 4, 6, 8, 10, 12 or 16 images in various size and layout configurations, which all sounds very promising, until you realise that sixteen images compressed onto a 14” high resolution monitor, can provide some difficulties when it comes to identifying exactly what is going on in an individual picture (this problem still holds true for many modern Town Centre camera schemes, where many incidents tend to be missed, simply because the images are too small to observe properly).

The solution of course is to use a much larger monitor, but then the cost shoots up significantly, as indeed does the requirement for available space.

One particular technical problem of note, is that if you leave a mosaic on screen for long periods, it will very quickly ‘burn in’ to a conventional CRT monitor tube.

The solution of course, is to use an LCD flatscreen display, but then the downside is the substantial increase in
overall unit cost.

Nowadays, almost all system multiplexers are designed and built as display and record devices, capable of
providing a wide range of additional facilities, and indeed, as more and more systems convert over from analogue to digital recording, much of the display / recording multiplexer functionality is now built into the recorders as standard.

Record Multiplexers >>

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