IP v. Analog

What are the main differences between Analog and IP? When choosing a surveillance platform, there are a few significant factors to consider.



Analog and Digital

Video can be transmitted in two ways, Analog or Digital. An Analog video signal is a wave form, an electronic signal that varies in frequency. Digital video is a series of 1s and 0s (binary) or short pulses of electricity followed by brief pauses. Analog video has been around for about 50 years and is the basis for the majority of video surveillance systems. Digital video is newer and has only been around for about 10 years and is relative newcomer to video surveillance cameras.



Analog Video

Analog video (often referred to as NTSC in the US or PAL overseas) is transmitted in waves of electricity (1 volt peak to peak) over a wire. This is the kind of video signal you get out of a yellow port on a DVD player or VCR. Analog cameras have a Charge Coupled Device (CCD) board that captures the light reflected from an object and changes it into electricity. In surveillance, this analog signal is typically sent over RG-59 coaxial (two wires, one for signal and one for an interference shield) cable. This electrical current or analog video signal is received by a capture board in the DVR that converts it to digital video. The DVR displays this video on the screen and records it to the hard drive.



Analog Challenges

The biggest issue with analog video is the resolution (size) of the image is limited to standard definition (SD or approximately 720x540). Analog signals can offer suffer from signal loss. If the signal is too low you get a degraded version of the picture. Low signals are darker, have lower contrast, poorer colors and may shift (shake) from side to side or up and down. If the signal is too low no image is displayed. Low signals can caused by splitting the line (about 35% of the signal makes it to each of the ends), cheap thin cables, or super long cables. This is why iTech Digital uses quality thick cables and other specialty video equipment.



Digital Video

Digital video is encoded in a computer language of 1’s and 0’s to be transmitted. Digital video in the surveillance world is often referred to as Internet Protocol (IP) video. “IP” means that it uses the same networking standards as the Internet. All IP video is digital but not all digital video is IP. This transmission occurs typically done over DVI, HDMI, or over a Ethernet network (IP). Most modern video for TV and some movies captured using digital cameras. In this case the information is captured and stored digitally from start to finish. Network or IP cameras are all digital. They two have a CCD or CMOS chip but the camera never converts the signal into an analog wave. The information is digital from start to finish. Each camera is actually a mini computer which is why they tend to me more expensive.



Digital Challenges

Digital cameras are usually more expensive and do not work with traditional DVRs. There is no low signal strength for digital, it is an all or nothing format and cameras may drop out rather than displaying a poor image. Also, just because a signal is Digital does not mean that the picture quality is better. A good quality Analog camera may be just as good or better than an IP camera.



What does iTech Digital use?

We use both analog cameras (i2i or i2i Blue) or digital IP cameras (i2i Blue only).

Matt Craig
Matt Craig is the Technology Development Manager at iTech Digital. He works with our security solutions installation and support team to build partnerships with customer IT departments.
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