Analog cameras are used for video surveillance and control due to the sensitivity and signal transmission over a wide dynamic range. Distribution of these devices was due to the good price-performance ratio of the installed video surveillance system.
The composition of the security video system
Video recorder is the basis of surveillance equipment built on video cameras. Being a VCR with additional functional add-ons, the device registers, reads, records the incoming signal. Analog video cameras of the PAL / NTSC range are connected to the DVR to transmit images with recording and viewing on the monitor. System components operate using a power source, the design and power of which depend on the necessary conditions. With the help of cables, connectors, receivers and signal transmitters, the DVR and cameras are combined into a single network.
Features of continuous video technology
The physical transfer of data from the sensor to the recorder in the form of a continuous signal is obsolete, but it is still used due to the simplicity and low price of devices operating on this principle. The use of analog video cameras reduces the cost of installing and maintaining small surveillance systems or when expanding them. Surveillance using analog video technology is carried out in large areas, when the control center is located at a considerable distance from the observation zones.
Differences from digital video technology
Different types of video equipment differ not only in the transmission method of the optical image. PAL / NTSC cameras appeared earlier, but now they are obsolete. A digital image is obtained without noise and interference, but the cost of purchasing components increases by two to three times. Using analog video cameras does not allow you to analyze streaming video for fire or smoke, to recognize numbers or faces in automatic mode.
Each individual camera unit is connected using its own coaxial cable, unlike digital ones that can operate from a single network interface via a twisted pair UTP cable. An analog system cannot work without a DVR, and some digital models can record video in the internal memory. All devices of the PAL / NTSC security system need to install separate power supplies for network components, and digital video equipment is powered by a cable that transmits a signal.
Benefits of PAL / NTSC Camcorders
Despite the outdated technology, analog video surveillance is popular not only due to the low price of components, but also by several positive qualities of the system. The signal from the cameras is transmitted directly, without delays and transformations, and the image is recorded by the DVR, which also displays it on the monitor. If necessary, additional elements, for example, motion sensors, are connected to the DVR. Maintenance and adjustment of the system does not require high qualification, therefore, along with low costs for purchased equipment, the cost of specialists is reduced.
The removal distance of the outdoor analog video camera from the control center is 300-350 meters versus 90-100 meters of digital models, which allows you to cover a larger area for surveillance. The resulting image takes up less memory in the recorder, which makes it possible to record video longer or install more cameras at the same recording time.
Application of PAL / NTSC video surveillance technology
A relatively small budget imposes restrictions on the choice of equipment for protection and monitoring. Sometimes it’s better to put in more cheap cameras than to use expensive components that are difficult to set up. Analog video surveillance is suitable for areas remote from the city where there are problems with access to the Internet and building a remote network - in cottages, in country houses, garden societies.
The protection of large perimeters imposes restrictions on the use of digital cameras. The maximum length of coaxial cable allows you to operate security video systems at large facilities with a small number of cameras.
Using AHD Cameras
From the user's point of view, digital and analog video cameras differ in image quality and price. The security systems market has replenished with AHD equipment combining the advantages of analog systems with digital FullHD quality. Installing a DVR using AHD technology makes it possible to install analog cameras of the old and new models at the same time. This expands the scope of application of analog surveillance systems, combining the low price of components with high quality of the signal output to the monitor. The transmission range of the signal over the coaxial cable in this case increases to 500 meters, but the required amount of memory for recording video becomes larger. AHD equipment is more expensive than classic, but cheaper than digital.