Railway Transponder Detection System

With the development of high-speed railway, there is increasingly challenge on the reliability of data transmission between the train and balise. In the"Balise Engineering factor (Temporary)"which was promulgated by Ministry of Railways in 2004, strict standards was formulated which is about the installment position of balise and the signal's quality of active balise C interface. To guarantee the train safety operation, the regular examination and maintenance is needed to the installed balise, which brings great problems for practical work. At present, manual survey through simple measuring tools is mainly used to detect the installation location of balise with the test precision and efficiency very low. The detection for the signal of active balise C interface is only judged via measuring peak-peak value with the inaccurate test result. Balise Comprehensive Measuring System is composed of handheld instrumentation, test channels and PC application software. Automatic and correct measurement can be realized to the location of installed balise, which has progress; Separate examination to the DBPL signal can be realized, which has innovation. Great sense is made in advancing the automation of train examination and safeguarding the safe operation of train.In the thesis, innovative research and design is made to three parts, including the capacitor sensor, conditioning circuit and the DBPL (Differential Bi-Phase Level) signal detection circuit. The primary content is as follows:1. Research on distance measuring channel: Starting from the principle of displacement measuring, differential capacitive transducer is established and upswing is proposed to enhance linearity, sensitivity and anti-interference through comparing advantages and disadvantages of various displacement sensors, which has progress. A examination method of pulse-width modulation based on the RC charging and discharging, is proposed through comparing domestic and foreign conditioning circuit, which has practicability and meets the system's requirements.2. Research on signal measuring channel: The active balise C interface signal is studied in the thesis. According to the encoding method, the decoding circuit is designed and a scheme is chosen. Four kinds of targets, including the sine wave amplitude, the sine wave frequency, the pulse wave amplitude and the pulse wave frequency are obtained through the separate examination, by which the signal can be detected correctly. Moreover, the type of electronic devices and the design of anti-interference on measuring channel circuit are discussed in order to enhance the system's stabilization.3. Data processing and error analysis: the measuring conditions are introduced, including system's measuring environment, methods and equipments, and the measuring results are offered. Various indicators of measuring distance and measuring signal channels are verified through processing and analyzing the data. The test results indicate that the requirements of the system can be both met by the measuring distance and signal measuring channels. Currently, the Balise Comprehensive Measuring System has passed the field application test and the government's authentication. It will soon be putted into practical use.