Study On The Method Of Detecting Frequency-shift Track Signal And Its Realization Based On FPGA

Railway is the important equipment of the transportation in our country, it isdisplaying an important role in the development of the national economy. As the railwayspeed increasing,driving safety has become the focus of the people. In order to ensure thesafety of the train, we need to ensure that railway signal received correctly. Therefore, thedetection of Frequency-Shift Track Signal’s detection has become a focus of research.Frequency-shift track circuit system used two categories: China’s self-developedEighteen Informations Auto-blocking system and UM71non-insulated track circuitsystem. Both of the two system are selected frequency as pass parameters, so as to realizethe automatic control of the train.In this paper, Through analyzing the spectrum of the frequency-shift signal,and onthe basic of the shortcomings of the traditional detection methods, we can put forward anew method for detecting Frequency-Shift Track Signal’s frequency parameters. Due tothe high frequency parameter accuracy requirements, we propose a sub-samplingtechniques to reduce the sampling frequency of the signal; For Frequency-Shift TrackSignal energy rather concentrate characteristics, we put forward the under-samplingfrequency spectrum refinement to improve the resolution of detection. UM71trackcircuit, it has only one peak,then the carrier frequency is the peak frequency, thespectrum of Eighteen Informations Auto-blocking system has two peaks, the the carrierfrequency is the average of the sum of the two peaks frequency, due to the deviation ofthe two kinds of systems, thus accomplishes the detection of the upper and lowerfrequencies of the signal.At last,we give the parameter detecting system based on FPGA.In hardware,thispaper design central process and control module which taking EP4CE115F29as core.Italso includes a signal preprocessing circuit,a power supply circuit,a memory circuit and adisplay circuit,and Nios II soft-core system architecture,which have given the corresponding schematic design.The software has done a detailed exposition separatelyfrom the main program, each functional module design ideas, software process.