Research And Design Of Portable Balise Detection Tool

In the high-speed railway signaling system,the balise is an important source of information for the train.It's packets are vital to the entire railway communication systems.This paper is based on the laboratory project of balise transmission system,to develop a portable device that can achieve packet reading and writing tasks for balise.Meanwhile,in order to provide more support for the active balise,this paper also adds quality detecting function for DBPL signal issued by C interface units.This paper first designed a hardware platform using Altera's Cyclone III FPGA as processing core,then realized the entire software architecture on this platform.The designs of modulation and demodulation algorithms as well as digital filter are more crucial in this paper,and they are achieved by using Verilog HDL after a variety of research to select the optimal one.To ensure the stability and reliability of the program,Matlab and Modelsim are also used to do the simulation and verification.In this paper,the following work are completed:1.Built the hardware platform:through analyzing the function requirements,the hardware platform is divided into four parts,which are power supply circuits?FPGA and it's configuration circuit?USB interface circuit and antenna with amplifier circuit.This paper completed the work including device selection?schematic design?board layout?vote?welding and debugging.In the paper,the schematic are described in detail and I also makes a brief introduction of the PCB layout design.2.FPGA software design:This paper uses top-down design methodology to design the software architecture.The program is divided into 4 function parts,they are controling and communicating section?read balise section?program balise section and DBPL detecting section,this paper also implements the sub-modules of these functions sections of which the steps and processes is given in this paper.3.Reaserch on digital filter:reaserch the advantages of different types of digital filters and the merits of various implementation structures.Giving a detailed description of design flow of digital filter through finishing the separation of the two carrier frequencies of the FSK signal with ?R filter.4.Study the algorithm:Investigating the FSK demodulation algorithm,OOK modulation algorithm and DBPL decoding algorithm.In this paper,various algorithms are derived and explained,the implementation steps and processes are also given.This paper has designed a portable balise detection tool that has been used in practice.