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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.

They say a picture is worth
a thousand words ....


Conventional (CRT) Colour Monitors

In recent years, the swing away from monochrome towards full colour operation, hasn’t been driven so much by the improvement in technology, but more likely the overall reduction in relative cost.

As modern high resolution colour cameras are today little different in price from older jobbing black and white units, it’s now much easier for end users to invest in impressive technology without breaking the bank ... unless of course they’re bank robbers .... obviously.
Anyway, back to Colour Monitors, what can we say about them. Well using conventional Cathode Ray Tube technology, they’re heavy, power hungry, hot and that’s just for starters.

There are actually two main levels of sophistication used in everyday CCTV systems. Firstly, there are a number of (normally 14” but up to 28” tube) plastic cased monitors, which are generally based on a domestic Television chassis, without the RF (Radio Frequency and programme Tuner sections) components installed. These relatively inexpensive models, provide a simple cost effective solution for most basic applications where only one or two monitors are to be used.

Although relatively low in terms of achievable resolution (generally 280 - 300 lines on average, although some will scrape 400 lines), they will nevertheless display a very acceptable picture quality, which in truth would fulfil many applications satisfactorily. Most will also be able to reproduce sound through an internal speaker, although this is normally the sum total of the monitors capabilities.

The more expensive metal cased versions, are true ‘system’ monitors, with the ability to provide centre resolutions of up to 800 lines or more in some cases.

It’s important to remember that as with all CRT based units, the edge definition will normally be significantly less, and overall picture regularity may indeed vary from unit to unit.

Continued>

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