CCTV HD-CVI is a solution for megapixel high definition applications, featuring non-latent long-distance transmission at a lower cost. The name has to do with its base band and quadrature amplitude modulation technology, which is able to avoid CVBS cross talk, completely separate brightness and hue signal, and further enhances video quality.
The HD-CVI solution incorporates both cameras and DVRs. The system is star topology structured — the DVR serves as a node for an over coax P2P (Point-to-Point) transmission to the camera. The technology offers two specifications: 1080p (1920×1080) and 720p (1280×720). In addition, the technology features the Auto Signal Compensation (ASC) patent, which only allows an extremely low signal distortion along long-distance transmissions.
Transmitting data over 500m over a coaxial cable can be realized, depending on the cable selected. Cable 75-3 and 75-5 are recommended for transmissions within 500m, cable 75-5 and above for over 500m.
3 Signals in 1 Coaxial Cable
HD-CVI composites video, audio, and control signals together and then transmits them over one coaxial cable, simplifying installation.
To further realize multiple-signal transmission over one cable, both audio and dual-way data communication signals are embedded in a blanking zone. This enhances synchronization with the video signal and supports a max sampling rate of 44.1kHz thanks to ASC.
The forward and reverse data channels are composited in the frame blanking zone, realizing a two-way end-to-end transmission to support control commands such as camera focus, PTZ control, real-time alarm, etc. The forward outputting data supports a high transmission baud rate, as the sending time and electric signal baud rate are predictable, and the receiving end is of high ASC performance.
On the contrary, the reverse outputting data supports a lower baud rate due to its low signal frequency and limited data, which are affected by impedance matching and channel transmission uncertainty. However, by adopting ASC, the reverse channel can restore some degree of electrical signal during long-distance transmission.
The HD-CVI solution can not only render smooth HD transmission during long-distance transmissions, but is also free from IP hassles and allows for simple installation; it also features a no-latency capability for real-time performance. With no need for compression processing to maintain its original video quality, it is able to present good quality vivid images. In comparison with other analog systems, HD-CVI has an advantage on the transmission distance front, as it can transmit 500m by using 75-3 cable for general transmission media and features a low signal distortion rate.
In a word, HD-CVI not only provides a good solution that offers megapixel image quality over long-distance transmission, but also ease of installation.