Monitoring the default installation is webcam now, so most of our technical articles are for network camera, of course, there are friends will ask analog cameras in the background, especially about AHD, TVI and CVI cameras, there are several friends asked.
Although not many use, but still spend a time alone and talk about all.
AHD, TVI and CVI is to simulate all three high-definition cameras.
High-definition cameras, AHD simulation is one of the analog camera, it and traditional analog equipment operation, using ordinary SYV video line - 75-3 or 75-5 coaxial transmission, but can realize low cost, long distance and anti-interference, no delay of mega pixel hd video transmission.
HDTVI hd video transmission interface camera, it is a high definition video transmission based on the coaxial cable of the specifications.
Compound HDCVI hd video high-definition cameras, it is a kind of based on the coaxial cable of the hd video transmission specification, adopts analog modulation technology transmission line by line scan high-definition video.HDCVI technology with independent intellectual property rights of the adaptive technology, to ensure the 75-3 and above specifications of coaxial cable transmission at least 500 meters high quality hd video, break through the existing high-definition video transmission technology transfer limit.
In use, CVI, TVI, AHD all follow simulation sd transmission way and the method, can reduce the complexity of the construction deployment, reduce the complementary material cost and the complexity of maintenance, as well as the technical requirements of construction personnel;Apply to the upgrade of the old system, but without changing the original system, on the basis of the standard definition easily upgrade to hd.
CVI, TVI, AHD hd on the coaxial cable transmission, and the transmission distance increase obviously;Has a higher resolution than ordinary simulation, no light crosstalk effects;Compared with the SDI further transmission, strong anti-jamming ability;Network hd compared with no delay, image lossless, convenient operation, etc.
Because a customer simulation to hd video line is long and has a sealed inside a wall, heavy wiring is difficult, so consider using coaxial hd.In the preparation in CVI, TVI, AHD three choose one.Because AHD is new and not as manufacturer's high-profile as CVI (bad), so the first test AHD.Hair is AHD 8-way DVR (support AHD - M, 960 p), and form a complete set of 960 p video camera.Immediately after the arrival of the test.Bright 960 p image effect is very sharp, do have the effect of 130 w pixels, and a webcam.After the 200 m video line test, barely visible image degradation.The effect is still good.But the backend has the following problem.
1. The first are DVR four modes: digital mode (1080 p, 960 p support 8-way AHD - M), the simulation model (support 8-way 720 p AHD -l, D1, etc.), 4 road network 1080 p model, 1 road network 1080 p + 8 road 720 p mode.If you are unable to access hd 960 p mode analog cameras, and connected to the analog cameras and unable to access the image after good 960 p.So my 960 p hd can run independently, can not coexist and analog cameras.This I asked the dealer, I can make it 4 960 p + 4 road D1 patterns, he said no.
2. AHD -m models appeared to maximum 8 road now.Some other solutions for 16 and 32 channels.My clients are now 16 road (or more) of the DVR, so it is unable to fully replace.
AHD DVR still has many advantages, such as simulation, coaxial, network lines, to a certain extent compatible with simulation and quasi high definition coexist, plus open plan, does have some prospects.But as said above, there are a lot of practical problems, so now just wait and see.
