The Monitor
The monitor receives the transmitted electronic video signal from the camera and paints it across a
cathode ray tube (CRT) to display an image to a viewer. Although similar in function to a TV set, a CCTV monitor provides higher lines of resolution (better picture quality) and accepts only video signals rather than RF/antenna signals.

Lines of resolution refers to the total number of horizontal lines the camera or monitor is able to
reproduce. The more lines on a screen, the better or sharper the video picture will appear. CCTV
monitors can provide up to 1000 lines of resolution compared to an average of 300 lines provided by television sets.

Figure 13: Nine and fourteen inch monitors often serve as dedicated monitors. The 14-inch
size is also popular for call-up monitors. Monitor size is measured diagonally.

Several factors can affect the monitoring function: Size of the monitor (9" and 14" are popular sizes), its positioning and angle relative to where the viewer sits, the quantity of monitors, and the quality (resolution) of the monitor itself (see figure 13). In all cases, sufficient growth must be factored into any console design. It's also important to note that all monitors generate heat. Whether on a table or enclosed in a console, be sure to provide adequate ventilation and air-conditioning.

Most CCTV systems use both dedicated monitors and call-up, or switchable, monitors. A dedicated monitor displays the video from only one camera. A call-up, or switchable, monitor enables operators to "call or switch" different cameras to the monitor. Generally, call-up/switchable monitors are larger than dedicated monitors and give operators the ability to view multiple images simultaneously (multiplexed) as well as scrutinize the camera image more closely.

There are many different monitor sizes available. When choosing the proper size of monitor, you must first determine the distance of the monitor in relationship to the user. Also determine the quantity of cameras to be displayed on a given monitor simultaneously (multiplexed).

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