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EVERYTHING YOU NEED TO KNOW ABOUT ANALOG CAMERAS

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Analog Security Camera

WHAT IS AN ANALOG CAMERA?

Analog Cameras are Closed Circuit Television (CCTV) cameras. They were the first breeds of security cameras developed. They operate by sending analog signals (as opposed to digital, i.e. binary, signals) of live images over a coax cable to a device in order to have these signals rendered into viewable video. We won’t cover the details of analog or digital signals in this post, but you can visit our glossary if you are so inclined to learn more.

As mentioned, all analog cameras send their signals to be stored on an external device. Initially, these devices were video tape recorders. That is, the analog signal would be directly recorded onto a tape (thus preserving the analog format, since tape is technically analog). However, in modern times, the devices used to store and process signals are non-analog media, or digital video recorders (DVR). In short, the DVR converts the analog signal into a digital signal that can easily be processed into video and manipulated. Why does the signal need to be converted to digital? If the signal is converted to digital, you have MUCH more control of the data. That means that, through the DVR, you can manipulate the video (zoom in or out) and easily store a large amount of video footage since digital signals can easily be compressed. We will go into detail in a later post regarding DVR appliances.

LIMITATIONS & CONSIDERATIONS

There are two main limitations to analog cameras: lack of intelligence, and low video quality/image resolution. 

An analog camera does not have any built in intelligence. Its only specialty is transmitting video from one location to another. Any video manipulation has to be done on the DVR side. So… please keep this in mind when considering an analog camera. 

Regarding resolution, with analog systems there is an upper limit to the quality you can obtain. All analog cameras report resolution as TVL (the number of horizontal lines on a display screen). The TVL of analog cameras can range from ~300 (lower end) to ~600 for the highest quality analog cameras. 550-600 TVL is generally considered “DVD quality”. Even though DVD quality sounds good, in reality, it is not that great. The reason? TVL refers to the resolution of the sensor in the analog camera itself. However, the signal still needs to be transmitted via a coax cable, and it is this process that reduces the quality of the resolution. So, while you may have a DVD quality analog camera, the video you receive in the DVR is less than DVD quality.

One more important thing to consider is the frame rate of your analog device. Frame rate (or FPS, for “frames per second) is the rate at which images are displayed one after the other. 30 fps is considered “real time”, 15 fps is “perceived real time”, and at anything less than 15 fps, you being to see “jitters” where it appears that the video is “stopping and starting.” 

With analog systems, the FPS can vary depending on your setup. This is what you have to consider:

1) What is the Live View FPS? Live view fps is the frame rate you observed when watching all analog cameras real time.
2) What is the Record Rate FPS? While the live view of the camera might be 30 fps, the record rate of the DVR might be something different... To determine this, you have to look at fps per channel on your DVR and compare that to the fps of the DVR output. For example, the frame rate might be 30 fps per channel (per camera) on the DVR, but for the whole output of the DVR, it may be only 80 fps. This means that the sum of all the fps of each individual camera cannot exceed the 80 fps of the DVR itself! If this were the case what would happen? If you had 8 cameras attached to this particular DVR, and each channel for each camera can record 30 fps but the DVR can only record 80 fps total, then you would end up recording 10 fps per camera since 80 fps is the max the DVR can handle.

SO… WHY CHOOSE ANALOG?

Overall, we always recommend IP cameras. However, there are some advantages to analog systems.

Analog cameras are typically the cheapest types of surveillance cameras. If you have no choice and are on a tight budget, then this would be the option for you. Also, if quality was not your top concern (perhaps you just would like a camera for the comfort of having one, or as a visual deterrent for potential criminals) then this would an option for you.

Analog systems are also relatively simple, for a fully functional analog system, all you need is an analog camera, a cable of the right form factor (typically a siamese cable, which is a coax cable and a power cable contained within a single enclosure), and a DVR appliance.

Finally, with analog systems, since it is closed circuit, not only do you not deal with any hassles of networking, but you don’t deal with any of the issues encountered with networking/computer systems, the main threat being network security breaches.

"TAKE ME TO THE GOODS"

Take Charge Security offers analog cameras and complete analog surveillance systems. To browse and get familiar with what we offer, simply visit our surveillance system package collectionand/or our current selection of analog cameras. As always, if you have any questions, don't hesitate to contact us.

Yours in Security,

Dave & Mike


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