By: Arthur Cooper
Submitted: 2011-04-03 23:45:50 | Word Count: 664
These days there are more Closed Circuit TeleVision or CCTV camera systems than applications for their uses. If you are interested in such a system, it will serve you well to do some research before venturing out to make your fist purchase. At Security Camera King, we encourage you to shop around, because we know that we offer the highest quality systems and the best possible prices. After you’ve looked at other offers, we’re sure you’ll come back to us to make your final purchase.
You may be asking what is meant by the term “CCTV Camera System.” A CCTV camera system is simply a digital video camera system that normally includes a Digital Video Recorder and a display monitor. Today’s systems are entirely digital and the systems are component systems, meaning that when putting together your system, you can choose different pieces of the system that have different functions to tailor fit the system to your needs.
[ advertisement ]
First a little history. Closed Circuit Television or CCTV got its name way back in the days of analog transmissions. A typical video security system was referred to as a Closed Circuit system because the cameras did not broadcast their signals to the open public. These cameras were basically smaller versions of the cameras used in television studios. However, television studio broadcasts were amplified and distributed to the open public (i.e. anyone that had a receiver or television).
CCTV on the other hand, consisted of a circuit of one or more cameras, each connected to a video recorder by means of a video transmission cable. Analog CCTV camera systems recorded their video on magnetic tape, usually VHS or Beta format. The used tape had to be ejected and a new one put in place every few hours or a “loop” tape was used. When a loop tape reached the end of the tape, it simply continued over again on the beginning of the tape, re-recording over the original.
Today, CCTV camera systems are digital. Instead of sending their video transmissions in analog type signals, they are sent in binary or digital form, usually in the form of bits or bytes, the same sort of digital segments used by personal computers. The camera data is compiled into a digital video file which can either be stored on a hard drive disk or other storage media and/or viewed on a digital monitor.
Since the data is digital, many of the individual electronic components of a modern CCTV camera system are the same things used in personal computing. For example, the computer Hard Disk Drive or HDD is the major constituent of the DVR storage. A computer processor, much like the Central Processing Unit or CPU of a personal computer compiles the digital video files, controls and coordinates camera activity as well as playback and other DVR functions.
Since the original video security systems were analog and were called CCTV camera systems, there may be some confusion or crossover that exists today when describing digital video systems. For example, analog CCTV cameras displayed their video on older CRT (cathode ray tube) type television monitors. The CRT monitor displays a picture by rapidly projecting horizontal lines across the screen; the more horizontal lines per fixed vertical area, the greater the detail or resolution of the video.
Digital video is not displayed in horizontal lines, but as a series of horizontal and vertical dots called pixels. These pixels may be circular or square in shape. Generally speaking, the more pixels in a video for a fixed area, the greater the detail of the video because the dots are much smaller. This allows for finer detail in the image.
So where’s the confusion? Today you may still see CCTV camera systems that describe their clarity or detail or resolution of the camera in terms of Televsion Lines or TVL. Yet other cameras may describe their resolution in terms of pixels. For more information on determining the equivalencies of resolution for these systems see the articles in our knowledge base.
Since most of our monitors that are manufactured today are no longer CRT type but are more commonly LCD (liquid Crystal Display) or LED (Light Emitting Diode), it would see logical that over time, the TVL descriptor will eventually lose out to the more familiar digital “pixel” resolution (for example 720 X 340 pixels), but for the time being, it is well enough that you are aware that the difference exists.
Author Resource:-
Click here to read the rest of CCTV Camera Systems. If you enjoyed this article, you also might like our other stories about Security Cameras.
