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Analog versus Digital Recorders NJ |
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The need for the storage and subsequent retrieval of video has been apparent since the first live viewing CCTV station was installed. For nearly two decades, VHS tapes have been the most prominent method of video storage. In recent years, major advancements in digital recording and storage technology have finally given the users of CCTV products a viable alternative. "Analog" refers to information being presented continuously, while "digital" refers to data defined in individual steps. Analog information's advantage is its ability to fully represent a continuous stream of information. Digital data, on the other hand, is less affected by unwanted interference, or noise. In digital computers, data is stored in individual bits, which have a value of either 1 (on) or 0 (off). If graphed, analog signals are shaped as sine waves, while digital signals are square waves. To put it simply, analog images are recorded onto VHS tapes while digital images are recorded on a variety of mass storage devices, such as a hard disk drive. To clarify further, cameras transmit images in an analog format. While time lapse VCR's simply record these analog images, a High Definition Digital Recorder converts the analog signal to a digital format so it can be compressed and stored. Once in a digital format, the data can be easily preserved and quickly searched in a fashion similar to an audio CD. It is features such as this that have clearly made High Definition Digital Recorders the CCTV recording unit of choice. Some addition information to support this statement is presented below. Analog has several disadvantages that Digital Recording does not: Analog systems are extremely hard to upgrade and their feature sets cannot be modified without adding or replacing expensive hardware. Many problems arise when data is stored on VHS tapes. For example, VHS tapes must be searched sequentially which is time consuming and expensive. The quality of video stored on VHS tapes can be dramatically reduced when tapes are copied or reused. An archive of VHS tapes requires a lot of storage space and can be difficult to organize and maintain. Finally, tapes must be manually switched periodically requiring extra attention and personnel.
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In sharp contrast, High Definition Digital Recording offers the following advantages: High Definition Digital Recorders are based on industry standard industrial grade computer hardware. This means replacement parts are readily available and software may be upgraded through a remote or internet based connection. HDDR's store video in an efficient digital file format: Video clips are digitally watermarked to prevent tampering. Through compression technology, digital images require little storage space. Digital image quality and resolution are much better than analog. Copying a file is fast, easy, and never affects the image quality. Historical footage can be accessed in a matter of seconds by searching according to time, date, or alarm activity. Digital images never wear out. They can be viewed thousands of times without affecting the image's quality. Historical and live video can be access anywhere in the world through a wide variety of remote connection types. Motion detection is easily set up allowing users to define multiple motion detection zones within the viewable area of each camera. The sensitivity may also be quickly adjusted. High Definition Digital Recorders can replace several pieces of analog equipment including time lapse VCR's, multiplexors, PTZ controls, looping switchers, and remote viewing stations. As clearly demonstrated here, the vast improvements in digital recording technology have finally given CCTV users a crystal clear alternative to the world of analog. |
AACOM Inc. |