Simulation And Research On Coding Fsk Signal In The Active Balise Monitoring System

In recent years, the domestic railway develop fast. In the construction of passenger transportation dedicated line and the high-speed railway, the balise has a very widespread application. The balise sends the state information of the line situation by the form of telegram. The train analyses the telegram after receiving it, and forms the velocity curve based on the telegram, in order to guarantee the safe transportation. The balise system plays a very essential role in guaranteeing the safety of the high speed movement of the train.But as the open transmission between the Train Control Centre(TCC) and the active balise trough LEU, there has been a number of faults, since the Ministry sped up the exiting line in 2007. All these faults have impacted the safety and efficiency of the transportation seriously. For this reason, the urgency issue we need to solve now is that the monitoring equipment should be developed for the active balise according to the situation of domestic railway in order to realize the real time monitoring for the passageway between the LEU and active balise.The author researched the structure, function and working principle of both ground and onboard equipment in balise system thoroughly, analyzed and summarized the faults and problems of the balise system in recent years. Also we stated the constitution and working principle of the monitoring equipment for active balise in detail, analyzed the problems of the monitoring equipment, and put forward the way to solve the problems.Through the deep research on the structure, function and working principle of wayside equipment and onboard equipment in balise system, the author analyzed and summarized 2FSK signal indicators in the transmission between wayside equipment and onboard equipment, proposed a detecting method which is applicable to the frequency, amplitude and other indicators of the 2FSK signal in the transmission in accordance with the proven Duffing oscillator theory. We established a mathematical model and realized the simulation of detecting telegram in the active balise monitoring equipment, verified the correctness and availability of the simulation through many experiments. Finally, we analyzed the influence of the noise on the system, and proved the superiority of the new way through compared with the indicators of the error rate in theoretical value of the conventional coherent, non-coherent detection system.