Research Of Balise Uplink-signal Receiver System

With the development of railway enterprise and the construction of the Passenger Dedicated Lines and the high-speed railway, the improvement of the railroad transport capacity and the railway transportation efficiency has always been the most concerning issue in the railyway system on the basis of the present railyway lines. Whether in TBTC or CBTC, balise has been widely used and played an influential role as one of the transmitting information methods between the trains and the tracks. At present, balise used in China is not yet domestic. Balise technology from abroad can only meet the needs of the development of railway construction. However, the core technology of the balise has been monopolized by foreign companies. Designing and manufacturing of balise with our own intellectual property have vital realistic significance and economic value.Based on the analysis of the composition, sorts, principles and application of balise, this thesis focuses on the research of balise uplink-signal receiver system. With the current situation of Chinese high-speed railway train control system, this thesis proposes a new balise uplink-signal receiver system program. This program is divided into three modules:data acquisition module, data demodulation module, decoding module. According to the features of uplink-signal, the parameters such as the quantity of transmitting information, carrier frequency, demodulation scheme, the rate of transmitting information and the transmission bandwidth will be determined. Because there are much more interference signals in receiver systems, the information modulation mode and the choice of carrier frequency are especially important. Concerning of the performance and computational complexity of several demodulation algorithms, this thesis adopts the differential detection solution transfer mode in the signal demodulation. Design of digital filter is an important part in signal processing. The band-pass, low-pass and delay filters are involved in differential demodulation. This algorithm is carried out by MATLAB. The differential detection solution transfer mode will be verified in simulation by using of the SIMULINK tool. Meanwhile, on the concern of the noise environment, the factors that influence the simulation result will be analyzed. On the basis of hardware digital signal processing technology, the differential detection mode is used to finish 2FSK signal demodulation slab design in this thesis.This thesis analyzes and researches into the CRC (Cyclic Redundancy Check) and descrambling algorithm of the balise recriver on the analysis of the FFFS (Form Fit Function Specification) coding strategy of balise and the basis of the telegram decoding strategy. According to coding theory, two methods will be adopted to verify the CRC. In accordance of the process of scrambling, the descrambling operation at the receiving side will be carried out. FPGA is used to complete the design of the balise telegram decoding program. And each functional module of this program will be divided. Finally, the two modules which are CRC and the descrambling module in simulation in the balise telegram decoding process will be achieved by QuartusⅡ.