Design And Implementation For Key Technique In Emergency Broadcast AM/SW Overcast Net

Since 2009, the national emergency broadcast system’s construction has been steadily improved with the general thought of each center with a covering net. It focuses on strengthening the construction of pre-warning information releasing platform, improving pre-warning ability of the information terminal, so as to realize emergency broadcast by using the existing radio and television broadcast coverage resources. To realize the emergency broadcast in AM/SW radio overcast net, the thesis takes AM/SW overcast net’s construction for emergency broadcast system as the research subject, aiming at two problems of how to achieve the connection between AM/SW overcast net and the emergency broadcast information publishing platform, and how to achieve pre-warning function of the AM/SW terminal, and it emphasizes on three key technologies which are emergency broadcast message receiving, analyzing, terminal waking-up in the AM/SW radio transmitting station. The following work has been completed:Firstly, it elaborates the researching background and significance, the developing situation of emergency broadcast AM/SW overcast net, analyzes the key technology and problem in setting up emergency broadcast AM/SW overcast net, studies the relative basic theory, proposes and proves the feasible solutions, and then gradually finds out the method of each crucial technical link according to the technical route of the solutions.Secondly, it studies and realizes receiving data in emergency broadcast TS through UDP. According to the standard of digital audio and video transmission technology and emergency broadcast message transmission protocol, during the process of UDP receiving data, it designs the receiving cache model and proposes the double buffer memory processing method in the process of collecting the information, which can properly receive text and audio data packaged and released by emergency broadcast information publishing platform in AM/SW transmitting stations.Thirdly, it studies and realizes analyzing the emergency broadcast TS data. According to the format of emergency broadcast TS data, it presents an analysis algorithm of emergency broadcast audio data and description on the analyzing process of the emergency broadcast text contents, which makes the receiving device respond by address and output emergency program’s audio under control so as to realize the covering on the specified area by the emergency broadcast.Fourthly, it chooses DTMF signal suitable for AM/SW transmission as a remote wake-up control signal, develops the corresponding DTMF signal board, inserts the remote control signal by the switching device, and increases terminal DTMF receiving module to recognize control signal and automatically turn it on at the terminal. In addition, it also designs the security transmission mechanism to ensure the transmission safety and to prevent the terminal from being illegally used and controlled.Fifthly, it introduces the other technology links related to building the emergency broadcast AM/SW overcast net, fully evaluates the research project and proposes the improving direction and thoughts.By using the thought of reforming the existing transmitting station in emergency broadcast AM/SW overcast net,the thesis solves the connecting issues of AM/SW overcast net and terminal wake-up problem, and fills the blank in the application research of connecting AM/SW overcast net with emergency broadcast information management platform.It provide a safer and efficient method to realize the terminal waking-up technology which can be also used in common radios. Its results can be used as an emergency broadcast reforming project by existing AM/SW transmitting stations which are less cost and less difficultly constructed. According to the project, AM/SW transmitting station can use the existing transmitter and frequency point to realize emergency broadcasting, the audience can use the remotely wake-up terminal to broadcast automatically while the emergency broadcast is on.