冬瓜视频app下载

    Notice: Our company introduced the latest POE POE power switch and splitter (PD), fiber optic transceivers, etc., please consult
Current Position:Home > news
Products
Contact Us
Phone:0519-88025678
Contact:Mr chen
Phone:13306121036
Address:Changzhou Wujin Hi-tech District People's Road 151
news

Twisted Pair Transmitter role?

Standard video signal interface is typically 75Ω, unbalanced way , and twisted-pair transmission is 100Ω, balanced way, so we should use twisted pair transmission of video signals to try to resolve the 75Ω ← → 100Ω balanced and unbalanced ← → conversion issues . There are two ways to accomplish this conversion : one way is to use a passive transmission of the transformer, it does not have power , but will have some signal loss , limited drive capability ; Another is to use an active way through a broadband amplifier and a dedicated chip, and impedance conversion can be done only in a balanced manner , and can provide a stronger driving and amplifying the image signal to compensate for the disadvantage is the need to supply to work. Passive transfer can pass 300 to 600 meters, while the active transmitter can transmit about 1500 to 2800 meters .

 

冬瓜视频app下载    How to make wiring easy and economical to do it . Twisted : Twisted is an ordinary five eight-core four pairs , and each pair of lines of wire twisted together with each other all the way image transmission . So four of the eight core and four images can be transmitted , thus optimizing the use of larger wire .

 

    However, unlike the project site as we want to idealize will exist some distance between the camera and the camera , then gave wiring brought some difficulties. So give some suggestions on twisted pair cabling for reference.

 

冬瓜视频app下载    Pulls out a pair of pumping out a pair of wire cabling to the front when Jieshang Qu reach a point, and then reach a point . But such a connection to the cable is damaged ( the project is generally not recommended to use ) , when the wiring is complete connectors must handle .

 

冬瓜视频app下载    Comparison of long-distance video transmission , the use of the active transmitter. Wiring to a more centralized point , the transmitter in a box . Transmitter to transmit the camera coaxial with the end use of the active transmitter , the transmitter to the coaxial connection between the camera up to 200 meters permit filling attention ( when using a passive transmitter , the front and rear ends video cable connection can not be too long , it is best within a few meters ) .

 

    When using twisted pair transmission of power supply requirements are relatively high , the best selection of on-site power transformer , switching power supply centralized power supply , power transmission distance is not too long ( too far away will be powered when the power is low or unstable transmission causing image is not normal ) .

 

    PTZ or speed dome can pass control twisted pair transmission signal ( can pass 1000 m , preferably with six lines ) , the other is redundant twisted pair transmission of video signals. When more than one ball machine together, can control the line of string in the same twisted pair uploaded to control the back-end .

 

 [ Performance Analysis ]

    A coaxial cable in the monitoring system , using coaxial cable 75Ω-5 is more common. In general, the distributed capacitance of this coaxial cable in 50-60pF / m or so , plus the DC resistance of the cable , the signal will be transmitted by the attenuation. Tests show that the frequency of 5MHz signal coaxial 75Ω-5 in the transmission of 100m, will be attenuated about 5dB, the higher the signal frequency , the greater the attenuation suffered . A high frequency signal is a wideband video signal , high- frequency portion is located the color image , when transmission of a color image signal with a coaxial cable , the brightness and color will be attenuated , especially with increasing transmission distance of the color image fades even distorted. Found in the laboratory tests , a color image signal transmission in the coaxial 75Ω-5 about 200m, and the color has a significant amplitude attenuation . If you want to transmit over longer distances , but also join coaxial video amplifier , you can guarantee that the distance 2Km can transmit high quality video signals.

冬瓜视频app下载    2 , using twisted-pair twisted-pair transmission medium , the general use of the widespread use of Category 5 UTP cable. Its characteristic impedance of about 100Ω, the distributed capacitance of about 15pF / m, compared with coaxial cable attenuation greater coaxial transmission distance just 43%. Use twisted pair video transmission devices and automated with the use of twisted pair , you can ensure that the distance 1.5Km can be high-quality transmission of video signals. Use special instruments for laboratory performance twisted pair to transmit the image signal has been tested with the following results :

    Test Equipment : TektronixTSG-271PAL signal generator , TektronixVN700A video signal analyzer

冬瓜视频app下载    DUT : ONDON ( Anton ) twisted pair video transmission , Category 5 UTP cable

    ( 1 ) when the transmission distance of 300m

冬瓜视频app下载    Index : DG ≤ 1%; DP ≤ 1 °; SNR ≥ 65dB

    ( 2 ) the transmission distance is 1500m

冬瓜视频app下载    Index : DG ≤ 2%; DP ≤ 2 °; SNR ≥ 60dB.


    tags:
    Review the information
    I want to review
    Home | Company Profile | Honor | News | Products | Technical Support | Contact Us | 中文