Application of remote monitoring technology in radio and television transmission
Tonglu County is located in the northwestern part of Zhejiang Province. It is located in the upper reaches of Qiantang River and is affiliated to Hangzhou. The mountainous environment has brought many difficulties to the radio transmission of radio and television programs. In 2006, it was set up in Yuhua Mountain, Shishui Town, 38. 1 km away from the county seat. The broadcast transmitter and its supporting facilities, and in order to ensure the security of the equipment room and broadcast television programs, a network remote monitoring system was established. The water remote Yuhuashan network remote monitoring system is constructed by #analog camera + network video, audio server + serial communication device + network transmission device + remote client. The camera is used to collect the status of each instrument of the transmitter and its attached devices. The receiving device receives the sound transmitted by the broadcast transmitter, sends it to the network video and audio server, performs encoding processing, and packs it into an IP network data packet, and sends it back to the computer room of the broadcast television station outside 38. 1 km through the VPN optical fiber data private network. The computer room monitoring and management system uses professional software and its computer system for data processing. It can monitor the operation of the entire Yuhuashan launch system and its transmitter room in real time, and realize the remote switch transmitter control through the transmitter RS232 interface. Thereby ensuring the safety of wireless transmission.
1. System features
(1) Using the #Camera + Network Video Server + Remote Client? method to build a remote monitoring system, the monitoring system does not need to monitor in the local transmitter room, and realize remote video, audio and alarm monitoring functions in the remote TV computer room; (2) The image, sound, and control commands are transmitted using the VPN IP network platform; (3) the front-end camera uses a high-definition camera with infrared function to realize fixed-camera monitoring for a fixed key monitoring area, and the monitoring task can be conveniently completed at night; (4) The client can access the video image of the front end and *transmit the sound at any time; (5) The client can perform local recording, and can set and schedule the recording work schedule to realize multiple video retrieval methods; (6) the client can Playback and retrieval of surveillance video data; (7) The client can remotely control the transmitter to power on and off; (8) The client can perform voice intercom with any front end.
2 system technology principle
The remote monitoring system is generally composed of a total control center computer, monitoring signal equipment, network interface equipment, communication network, and connection lines between devices. Figure 1 is a structural diagram of a simple remote monitoring system.
Figure 1. Block diagram of the remote monitoring system.
As can be seen from Figure 1, the issues that we should consider when implementing remote communication are: The connection between the main control center computer and the network device (the remote station and the network device are connected in the same way); modulation, coding equipment and communication network Connection; How modulation and coding equipment works; Choice of communication network; How to realize communication between remote station and main control center computer (communication protocol problem); Data management problem, data obtained by monitoring should take corresponding measures, do well Save your work and view it at any time.
The system consists of three parts: front-end equipment, image processing and transmission equipment, and network client. The front-end equipment is composed of a camera, a bracket, a video and audio server, an RS232-RS485 converter, an audio receiver, a network switch, a fiber-optic transceiver, and the like, and is responsible for collecting and transmitting video signals, audio signals, and alarm signals. The image processing and transmission equipment in the system includes a network video and audio server, an audio receiver (R401), a serial communication converter (485-232), a fiber optic transceiver, etc., and the audio receiver receives the radio wave sound sent by the transmitter and sends it to the network server. It is transmitted back to the remote monitoring room to realize the real-time monitoring function of the sound after the launch. At the same time, the room environment video signal and the transmitter status meter signal are transmitted to the remote client through the LAN or the wide area network, and the transmitter control signal and audio sent by the client can be received. Intercom signal. In the construction of transmission network, full consideration is given to the security issue of broadcast television transmission. Fiber and Category 5 are used as transmission media, which are constructed by VPN private network. VLANs are divided in VPN private network channels, and images, sounds and data are in the same VLAN. Transmission, control information is transmitted in another VLAN, which improves the security level of the monitoring network, ensures the absolute security of the transmitter operation control instructions, and converts the RS232 serial communication mode to the RJ45 network mode through the RS232-RS485 converter. The serial communication is limited by the length of the line. By using the serial communication technology, the real-time control function of the transmitter is realized 38 km away.
The network client refers to the user terminal that needs to perform remote monitoring of the network. It consists of a computer and client software. The client is mainly responsible for functions such as image display, video recording, playback and transmitter control. When the client performs remote monitoring, the transmitter The reflected power, incident power, voltage, current, etc. are reflected to the management personnel through the control software in real time. At the same time, the video and audio signals can be stored synchronously, and the sound and image data are packaged together. The sound quality during playback is not distorted, and the recording speed can reach the full speed. Real-time 25 frames / s (PAL), support multiple hard disk loop recording, no need to manually change the disk.
3. Conclusion
The application of Tonghua TV station Yuhuashan monitoring system has improved work efficiency, reduced operation and maintenance costs, and more importantly, provided real-time dynamic equipment operation and data parameters for technicians. Equipment and system functions are better played. Broadcast security provides technical support to maximize the safe broadcast of broadcast and television signals.
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