Research And Design Of Portable Balise Detection Tools On FPGA

The transponder is one of the most basic information storage and transmission units in the whole railway traffic system,especially in the train control signal system of high speed railway,which provides necessary information and state information for the train.The normal operation of the transponder and the security of the internal message information are related to the safety of the entire railway network,so it is necessary to make regular maintenance for the answering device.This paper,taking the actual project of the laboratory as the background,analyzed the equipment requirement and the feasibility of the implementation scheme,developed a portable transponder detection device(BEPT)to realize the convenient operation of the corresponding answering device detection and information updating.The system is mainly divided into two parts:hardware and software.In the early stage of R&D,the research status of transponder detection equipment at home and abroad was investigated,and the advantages and disadvantages of the same type of equipment design were analyzed and referred.This paper analyzes functional requirements and identifies two main functions of answering and reading.After modularizing the function,the hardware and software system is designed:the hardware part,the Cyclone ? series field programmable gate array(FPGA)chip of ALTERA company is selected as the digital signal processing chip,and the MK60 of NXP company is selected as the main control chip for display and interactive operation,and the ADC sampling circuit is designed.The power amplifying circuit,antenna circuit,filter circuit and power circuit are used as peripheral circuits.The algorithm and software realization,the theoretical analysis and Simulation of the frequency shift keying(FSK)demodulation algorithm are carried out.From the complexity of the algorithm and the environment conditions of the equipment application,the absolute value detection is chosen as the core demodulation algorithm and the calculation is made.The difficulty and performance of the method are simulated and analyzed.A modified binary switch key control(OOK)modulation algorithm is designed to realize the dual functions of OOK signal modulation and power supply.The parameter design of the modulation algorithm is theoretically analyzed.The comparison and verification of the measurement results of the actual equipment shows the rationality of the OOK modulation algorithm.After the core algorithm is completed,the function of the software system is realized by Verilog HDL.After the completion of the hardware system design,the power consumption of each circuit module is calculated,and the circuit is optimized,which improves the system efficiency and prolongs the battery life.After the completion of the FPGA program,the logical simulation is carried out with the Modelsim software,and the logic function of the system is verified with the data of various conditions as the test sample.In the online debugging phase,the waveform of the key signal was analyzed by signaltap sampling,and the working condition of the equipment was tested for a long time.To sum up,this paper designs and implements the transponder detection equipment and has entered the railway field work through acceptance.