Dahua Technology releases High De nition Composite Video Interface (HDCVI) technology of Independent Intellectual Property Rights. HDCVI is a
video transmission technology in high de nition via coaxial cable, allowing reliable long-distance HD transmission at lower cost, while complex
deployment is applicable. HDCVI modulates video signal to level and then transmit by adopting base-band and quadra
ture amplitude modulation; which is also the reason of its
naming. This technology avoids the cross talk of CVBS and completely separates the brightness signal and hue signal, hence further enhances video
quality. HDCVI o ers two speci cations — 1920H (1920×1080) and 1280H (1280×720); which are compatible with the industrial standard 1080p(1920×1080)
and 720p(1280×720). In addition, the technology features a patent named auto signal compensation (ASC), which only allows an extremely low signal
distortion along long-distance transmission. HDCVI solution incorporates both cameras and DVRs, and the system is star topology structured; DVR is served as a node to have an over coax P2P
(Point-to-Point) transmission to camera. Cable selection is based on transmission distance: cable 75-3 and 75-5 are recommended for transmission
within 500 meters, cable 75-5 and above for over 500 meters. Connector or jointing technology could be applied for connecting and the installation is
exactly the same as that of conventional analog devices, which posts no special requirements either for indoor or outdoor scenarios with better
anti-interference capability o ered. To further realize multiple-signal transmission over one cable, both audio signal and dual-way data communication signal are embedded in a blanking
zone; which enhances the synchronization with video signal; and max supports 44.1kHz sampling rate thanks to ASC. The forward and reverse data channels composite 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 and etc. The forward outputting data supports high transmission baud rate as the
sending time and electric signal baud rate are predictable, meanwhile, the receiving end is of high ASC performance; on the othr hand, the reverse
outputting data supports lower baud rate due to its low signal frequency and limited data, which is e ected by the impedance matching. However,
with ASC adopted, the reverse channel could restore electric signal during long-distance transmission at some degree. Therefore, HDCVI is an optimal solution for megapixel high de nition application, featuring non-latent long-distance transmission at lower cost.
