CCTV cable used for CCTV
The CCTV cable used for CCTV is coaxial cable with an impedance of 75 ohms.
CCTV cable can be divided into baseband coaxial cable and broadband coaxial cable (i.e. network coaxial cable and video coaxial cable). Coaxial cable is divided into 50 Ω baseband cable and 75 Ω broadband cable. Baseband cable is divided into thin coaxial cable and thick coaxial cable. Baseband cable is only used for digital transmission, and the data rate can reach 10Mbps.
Closed circuit television cable refers to a cable with two concentric conductors, and the conductor and shielding layer share the same axis. The most common closed-circuit television cable is composed of copper conductor isolated by insulating material. Outside the inner insulating material is another layer of ring conductor and its insulator, and then the whole cable is wrapped by PVC or Teflon sheath.
Television monitoring system
TV monitoring system is one of the important means of modern management, detection and control. Closed circuit television monitoring system can show the picture of the monitored and controlled object in real time, vividly and truly when people cannot or cannot observe directly. People use this feature to obtain a large amount of information in time, which greatly improves the accuracy and reliability of the anti-theft alarm system. Moreover, TV monitoring system has become an extremely effective observation tool for people to monitor and control in modern management.
In modern intelligent buildings, security center must be set up. Multiple CCTV monitors can be set in the security center to observe the population, main channels and important parts at any time. CCTV monitoring system is mainly composed of camera or imaging device generating image, image transmission device, image control equipment and image processing and display, CCTV cable and recording equipment. The system installs the camera in the monitoring place openly or covertly, and the captured image and sound (as required) signals are transmitted to the controller through the transmission cable. It can manually or automatically select the picture to be taken, and can remotely control the variable lens and rotating pan tilt on the camera to search the monitoring target and expand the monitoring range. In addition to single picture and multi picture display on the monitor according to the setting requirements, the image signal can also monitor the on-site sound and record the required picture in real time. The TV monitoring system has real-time and high sensitivity, and can convert non visible light information into visible images, which is convenient for concealment and remote control; It can monitor a wide range of space, and can expand the monitoring range when used in combination with PTZ; It can real-time alarm linkage, freeze frame video and alarm.
The personnel on duty can conveniently realize various functions such as camera viewing, video recording, macro editing, calling, alarm monitoring, review and so on through the keyboard in the monitoring center. The system can also upload field images in real time in 7fcp / IP mode on LAN or WAN through network transmission equipment. On the integrated platform, the monitoring system can be linked with other security systems, including anti-theft alarm, access control and other systems. Any alarm information can be sent, the on-site image can be switched to the designated monitor for display, and the alarm video can be triggered.
Closed circuit television is opposite to open circuit television broadcasting of television stations.
Broadcasting is divided into wireless broadcasting and wired broadcasting. The open circuit broadcasting of TV station is equivalent to wireless broadcasting (the user obtains the TV signal from the antenna), and the closed-circuit television is equivalent to wired broadcasting (cable TV mode: the TV signal is transmitted from the satellite transmission end to the designated user through cable). It transmits TV signals through wires. It mainly converts audio and video signals into a certain RF signal (i.e. a certain channel), so that they can be transmitted in the closed-circuit television system.
Closed circuit television generally refers to television other than broadcasting, such as industrial television, military television, medical television, underwater television, etc.
Closed circuit television  is usually used in areas requiring monitoring, such as banks, casinos, airports, military bases, campuses, police stations and convenience stores.
In the commercial field, the closed-circuit television system can notice the situation in other different areas from a central control room. For example, if it is not suitable for people to monitor in person in some places, a closed-circuit television system can be installed for continuous video recording, or only monitor some specific events according to instructions.
Early closed-circuit television systems used video tapes as storage media. In recent years, single or multiple hard disks have been used as storage media to save the inconvenience of replacing video tapes and storage. If higher recording capacity and reaction speed are required, disk array cards are also used to strengthen the recording storage capacity.
The closed-circuit television industry has developed into a new form, that is, digital video recorders are used to record a large number of videos clearly, retain them for many years, and analyze or operate the saved videos.
However, the security video of daily property management is only retained for 7 to 30 days because the society has laws to regulate it. In the past, many crimes could be solved by closed-circuit video, such as sex wolves, shop theft, robbery and so on.
The simplest closed-circuit television uses a camera to send the shooting signal to the monitor through the closed-circuit CCTV cable, or send the shooting signal to multiple monitors through the multi-channel distribution amplifier.
The application scope of closed-circuit television is very wide, and it is expanding at an unprecedented speed. It can be said that closed-circuit television is indispensable in all sectors of the national economy where modern technology is used.
Closed circuit television monitoring system is an important part of the security technology prevention system. It is an advanced comprehensive system with strong prevention ability. It can directly watch all the conditions of the monitored place through the remote control camera and its auxiliary equipment (lens, PTZ, etc.), and can also operate in linkage with other security technology prevention systems such as anti-theft alarm system, Make its prevention ability more powerful. The technical requirements of CCTV monitoring system mainly include: camera definition, system transmission bandwidth, signal-to-noise ratio of video signal, system of TV signal, camera, etc.
The use of closed-circuit television monitoring system can protect personal safety, save time and cost, improve efficiency, realize real-time command and dispatching, process and save information. CCTV monitoring system has been increasingly widely used in public security, Finance (banks, postal savings, stock exchanges), industry and mining, traffic management (highways, national highways, urban transportation hubs), transportation (airports, docks, railways, highway passenger stations), hospitals, businesses (shopping malls, supermarkets, jewelry stores, wholesale markets), schools, residential property management, military Hotels (hotels, restaurants, office buildings), important material warehouses and security and other fields have become one of the symbols of modern management.