Application Of ZFFT Based On Polyphase Filterband In Detection Of Track Circuit Signal

Urban rail transit system is characterized by its high-speed, convenience and large capacity. Signal system which is the important control equipment of urban rail transit system for drive direction and train movement plays the important role in ensuring the drive safety, enhancing the transport efficiency and is one of key technologies of the rail transit system.It is necessary to detect parameter of track circuit with high precision and real time. FS-2500 track circuit is used in beijing metro line one and eight.It uses the FSK to transform control information.In current, the methods used to check the operation parameter of FS-2500 need to be improved.According to the characteristic of the FS-2500 FSK signal,a new ZFFT arithmetic based on polyphase filter is put forward In this paper.Some work as follows:1. Development of track circuit and some detecting methods are introduced briefly.The FSK signal of FS-2500 is analyzed in theory in this paper and precision and real time target is put forward.2. According to the characteristic of FSK, a new ZFFT method based on polyphase filter is introduced and used in the detection of FSK track signal with real time and high precision on the base of traditional ZFFT. Then with new digital signal processing technology, a new ZFFT with polyfilter is used in detecting FSK track signal With new digital signal technology this methed can be made into devices.3. The system is devided into several parts and designed.the software of this equipment is described particularly. Then, we tested the FS-2500 track circuit signal and gave the result of our method .Finally what we should do next is suggested.With this method,the detecting of FS-2500 track circuit signal can meet the demands of precision and real time.