What are the meanings of these CCTV system terms? IR LED, TVL, DSP, Vari-focal, CCD

by wale
(Lagos, Nigeria)


What are the meanings of these CCTV system terms:

2. TVL
3. DSP
4. Vari-focal
5. CCD


I will give you some brief answers here. For more detailed answers please visit the CCTV Glossary of Terms.


Stands for Infrared LED. For cameras that can be IR sensitive (meaning they have a cut off filter that moves) they can be equipped with IR LEDs. These IR LEDs provides light that is invisible to the human eye but the camera is able to see it even in complete darkness.

2. TVL

TV Lines. This is the designation for resolution in Analog Security Cameras. 380, 420, 480, 540 are samples of resolutions. I would not recommend anything below 540. Some of the cheaper models you see are 420 that I suppose there are still some applications where you can use them but I would make sure it is as close as possible to the subject.

3. DSP

Digital Signal Processing. Even in Analog cameras there are some adjustments made in the image using digital technology. This is where you are able to get some of your white balance, flicker control and other settings. The signal is converted back to analog when it comes out the other end of the camera.

4. Vari-focal

This is a designation for lenses. A lens that is Vari-focal means that you can adjust the field of view of the camera. Typical options would be 2.8mm to 12mm, 3mm to 8mm or possibly 5mm to 50mm. Other lens types would be a fixed or zoom.

5. CCD

Charged Coupled Device. This is the core of analog video technology today. Developed over 30 years ago it has been the standard used to capture video in many different imaging devices. From cameras, to copy machines, to point and shoot digital cameras, etc.

The largest manufacturer of CCD devices is Sony.

Hope that helps. Please check out the Glossary of Terms for more detailed information.

Peter Brissette
Security Camera Expert

Comments for What are the meanings of these CCTV system terms? IR LED, TVL, DSP, Vari-focal, CCD

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Jan 19, 2012
by: Anonymous

thank you very much to sharing your knowledge.

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