Types of Wireless Cameras
Simple and rapid deployment make wireless cameras a popular choice for many users, but there are a few different options for connectivity which can make a large difference in performance and image quality.
The classic method for wireless CCTV is to simply broadcast the signal over the air from the camera and have the receiver tuned to the same frequency, the same way broadcast television used to work - this is sometimes referred to as "analog wireless", and is still a common method used in many of the wireless kits you see available at retailers. This type of transmission is the least desirable as it does not have any mechanism for coping with signal loss. Any interference will cause the video to break up, become distorted, or black out completely. It can also be difficult to have multiple cameras of this type working in the same environment as they will often experience cross-talk with each other. In addition to the interference problems, analog broadcast CCTV is vulnerable to prying eyes, as anyone with a wireless scanner or even a baby monitor nearby can intercept and view the transmission.
A more modern version of this method which addresses many of these issues is digitally-paired wireless. This method modulates the video signal into a digital bitstream that is transmitted as data between the sender and receiver, similar to the way modern digital broadcast TV works. This allows the camera to become "paired" with the receiver, which creates a secured method of communication between the two, preventing any eavesdropping. Having a buffered, digital signal greatly improves image quality, and prevents any signal loss from causing distortion or noise. Though interference can still occur, it typically will not impact the signal unless it becomes bad enough to block transmission altogether.
At the endpoint of either of these methods, the receiver will output a standard composite NTSC video signal, which will be ready to feed into a typical DVR or other recording device. The extra electronics in the digital method make it a bit more expensive, but that is rapidly changing, and the benefits make it the better choice between the two methods.
A rapidly evolving alternative to CCTV is IP-based surveillance. In an IP-based security setup, each camera is a network device that outputs a data stream instead of a composite video signal; and instead of a traditional DVR, you use software to manage and manipulate the cameras. Wireless cameras that fall into this category use 802.11 "wifi" to connect to your wireless data network, just like a laptop, tablet or other computing device would. The video streams are read over the network by your network video recording (NVR) software. This provides a layer of security since the video is being transmitted as data over an encrypted channel, and also provides a stable image thanks to data buffering. In addition, IP is not limited to the standard NTSC output of analog cameras (720x486), and we are more frequently seeing megapixel cameras with full 1080p HD output and better. This type of system provides the highest quality and most stable video performance coupled with the best management features, but is the most expensive and complex to setup of the available choices.
No matter which wireless option you go with, none of them can currently beat a wired connection for reliability, quality and performance. All wireless devices are susceptible to interference in some form - the degree of compensation for this signal loss is one of the primary factors differentiating the available options.
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Submitted by Mark M. - 8/15/2011 @4:09pm
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|Submitted by RickCrown - 04/24/2013 02:26:30 AM|
|This post really very helpful as I am looking for a wireless camera for my home. These days I am very much worried about the security of my kids at home, when I am in office. I had read about home security.