CCTV Video Signal Measuring
It is quite common that in a CCTV installation, engineers experience poor video signal quality at the DVR end. You may have done all correct but you still can’t figure out why you can’t get the video signals right. You have used high quality cameras, you have ran the cable in metal cable trays and you have avoided all causes of interferences but you still experience poor video signals, degraded video footages.
In reality we often face the above mentioned challenge. To understand more about video signals, one should understand unit of measure used in CCTV video signals. I R E institute of radio engineering America set standards in measuring video signals, video signal is measured in voltage.
A good video signal should have 40 I.R.E units equivalent to 0.2857143 volts, unit is equal to 1 volt peek to peek. As this is hard to measure by a volt multi-meter, oscilloscope is used and it is not easy to use a bulky oscilloscope there are new compact tester have been induced.
Pictures that view in the monitor is created by cameras which produce synchronization pulses that occurs 15,750 times a second. Each picture frame will have one sync pluse which makes monitor to start drawing video lines across the screen. To form a video screen that we see in the monitor needs two frames and 262 and half pulse makes a frame.
If I.R.E is less than 40 units, pictures will break up or roll. If the I.R.E is more than 40 units, picture will be more gray and degraded.
Iris level setting for correct CCTV video output
The correct setting for white balance is 100 I.R.E units. Automatic or manual iris should be set at the same level 100 I.R.E units to avoid any washed out or dim picture.
Peek to peek measurement in CCTV video signal
A quick peek to peek measure will ensure that your CCTV camera is producing the right quality image. It should be 140 I.R.E units to get standard picture from a CCTV camera.
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