Research And Implementation Of 25Hz Phase-sensitive Track Circuit Receive Board Based On Cortex-M3

Track circuit is the basis for automatic control equipment of railway signals. The using of track circuit can automatically detect the position of the vehicle and control the display of the signal machine. Besides, ground signal can be passed to the locomotive, which can control the train. It's very important to monitor The parameters of the track circuit.This paper is derived from the project of Micro Computer Monitoring System of Beijing Jiaotong University. The station machines of micro computer monitoring system are composed of many collecting machines with different functions which each includes several collecting boards to collect useful parameters such as power screen, Electric Switch, track circuit and so on. On the track circuit, The monitoring function of phase angle is a important basis to determine whether there is a track on, which is of great significance to ensure the traffic safety. In this paper, the author designed a new Analog Monitoring Board of Railway Monitoring Machine based on TJWX-2006 Micro Computer Monitoring System Technology standard. A algorithm based on correlation function is put forward after analyze the signal character of the 25Hz phase sensitive track circuit. This algorithm can measure the amplitude and phase of the input signal, and can effectively inhibit the interference such as traction current frequency and random noise.In this system, the input signal is first isolated and transformed by Current Transformer, and then the signal Filtered by the VCVS circuit formed of operational amplifier is passed to the Cortex-M3 microcontroller core digital circuitry to be conversion, Operation, storage and at last output by RS-485 communication interface.