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2.4.
Audio/Video Input and Out Connections
2.4.1. Video Input
DVR (WITHOUT HDD) video input port to the BNC input signal requirements: PAL / NTSC BNC
(1.0VP-P, 75Ω). Video signal should comply with national standards, a higher signal to noise ratio,
low distortion, low interference; image must be clear, invisible change, real and natural color,
brightness is appropriate.
Ensure stable and reliable camera signal:
Cameras should be installed in a suitable location, to avoid backlighting, low light conditions, or the
use of good results backlight compensation cameras, low-light cameras. Camera and DVR (WITHOUT
HDD) power supply should be common ground, and reliable, in order to ensure the normal
operation of the camera.
Ensure stable and reliable transmission line:
Using high-quality, shielded coaxial good video, and based on the transmission distance to choose
the right model. If the distance is too far, should be based on the specific circumstances, the use
of twisted pair, add video compensation equipment, fiber optic transmission and other ways to
ensure signal quality.
Video signal line should avoid strong electromagnetic interference to other equipment and lines,
especially should avoid high-voltage current string into.
Lugs ensure good contact:
Signal and shield lines should be firm, well-connected, avoid Weld, lap welding, to avoid
oxidation.
2.4.2. Select and Connect the Video Output Device
Video output is divided into PAL / NTSC BNC (1.0VP-P, 75Ω) output and VGA output (VGA is
optional)
Choose to use computer to replace the monitor should pay attention to the following questions:
•
Do not keep long boot state to extend the life of the equipment;
•
Regular degaussing, which will help maintain the normal operation of the display?
•
Away from strong electromagnetic interference devices.
Use TV as a video output device is an unreliable alternative. It also requires minimizing the use of
time and strictly controls the interference power caused by neighbouring devices. Inferior TV
leakage risks may cause damage to other equipment.
2.4.3. Audio input
BNC connector (only one to support intercom function)
Audio input impedance is high, and therefore must be used active pickups. Similar to the video input
audio transmission requires line to avoid interference, avoid Weld, poor contact, and special
attention to prevent a string of high-voltage current into.
2.4.4. Audio output
Audio output signal parameters is generally greater than 200mv 1KΩ (BNC), you can directly connect
the low impedance headphones, powered speakers or other sound through power amplifier output
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