CCTV CAMERAS: DIFFERENCE BETWEEN ANALOG AND DIGITAL CCTV

Analog vs. IP Technologies

Analog Security Camera System Design

Description: The following diagrams depict the basic setup of an analog camera system and a network-based (aka IP) camera system.

Analog System Design

In the traditional analog CCTV application, security cameras capture an analog video signal and transfer that signal over coax cable to the Digital Video Recorder (DVR). Each camera may be powered by plugging in the power supply right at the camera or by using RG59 Siamese cable which bundles the video and the power cables. The DVR converts the analog signal to digital, compresses it, and then stores it on a hard drive for later retrieval. Intelligence is built into the DVR to handle such things as scheduling, motion detection, and digital zoom. Monitors for viewing the video are connected to the DVR, or it can be set up to publish over an internal network for viewing on PCs. The DVR can also be set up to broadcast over the Internet and can add password protection and other features. When broadcasting over the Internet, the video for all of the cameras is transmitted as one stream (one IP address). Therefore, it is very efficient.

IP / Network Security Camera System Design

IP Camera System Design

In the IP world, each network camera captures an analog image but immediately converts it to digital inside the camera. Some digital processing can happen right at the camera, such as compression and motion detection. The digital video stream is then broadcast over the local area network (LAN) using Ethernet (CAT5 or CAT6) cable. Power is supplied to the cameras through the ethernet cable via Power-Over-Ethernet (POE) adapters built into the cameras and at the (POE enabled) switch. (FYI – Older style IP cameras do not have POE built in so POE adapters had be added to the system like this.) The ethernet cable for each camera is plugged into the switch which feeds into the network hub. As with all network devices, some set-up needs to be done for each network camera to set up its IP address and other identifying attributes.

A Network Video Recorder (NVR) performs the same function as its DVR cousin in the analog world. It captures each camera’s signal, compresses, and records it. The main difference is that the video feeds are digital (and much higher resolution) and not analog. Software built into the NVR provides features such as intelligent search and zoom, etc. The NVR combines the video streams from the cameras and handles the broadcast over the LAN and internet for local and remote viewing.

 

Advantages of digital CCTV security systems over analog systems are numerous and include:

  • Not limited by distance because of its ability to use WiFi or an existing internet connection
  • Digital CCTV systems can be installed in New Jersey homes or businesses and be viewed by someone with a computer and internet connection living in New York City
  • Multiple cameras comprising a digital CCTV system can be directed to a wireless focal point that contributes to minimizing the amount of wiring needed to complete installation of such a system
  • Images transmitted by digital CCTVs are measured in terms of megapixels. Megapixels are tiny “dots” that compose a digital image and are able to provide images with greater clarity and resolution than images send through an analog security camera system
  • Hours of vital information captured by digital CCTVs can be stored efficiently on DVDs, CD-Rs, HDD or FDD to be viewed at later times
  • The flexibility and connectivity features of digital CCTVs allow them to be installed just about anywhere that requires protection from criminal elements.

High-quality and dependable CCTV systems sold by professional security companies like Vertex Security have the ability to capture at least 30 frames per second, which is considered “real-time”. Although two to six or seven frames per second is adequate enough to record a criminal, home or business owners using digital CCTVs entertain a much higher possibility than users of analog devices of helping the police find and arrest the suspect due to providing such high resolution images.

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