Frequency Shift Signal Detection Instrument Motherboard Hardware And Software Design

In recent years, China’s railway industry is growing rapidly, the train speed is also improved greatly. To guarantee the safety of the train, increasingly high demand is set on railway signal equipment. In order to further improve the Automatic Train Control system, ZPW-2000automatic block with jointless frequency-shift system is researched and developed in our country, on the basis of the introduction of foreign advanced technology. However, the matching detection equipments are relatively less, which brings inconvenience to the maintenance of the system.For this case, in the paper, the main board of a frequency-shift (FSK) signal detection instrumentation was designed. ZPW2000FSK signal can be detected, with He Shoubing’s signal detection board together. The main work is as follows:(1) The current FSK signal detection instrumentation was investigated, and the FSK signal and automatic block with jointless frequency-shift system was researched. On the basis, the detection targets were set, including upper frequency, lower frequency, modulation frequency and RMS voltage of the FSK signal. On the main board, the main function modules are keyboard, display, A/D converter, data storage, serial communication interface with PC. In addition, in order to enrich the instrumentation’s function, the detection of single-frequency AC signal and DC voltage were added.(2) After consulting many documents, a circuit with the core of AVR32MCU was designed. The corresponding design of hardware and software was completed.(3) In the lab, the main board and the signal detection board were debugged together. The results were as follows:measurement error of upper and lower frequency, and modulation frequency of FSK signal was less than±0.3Hz; frequency measurement error of single-frequency AC signal was less than±0.2Hz; measurement error of all voltages was less than±1%FS.The instrumentation is powered by battery, and the circuit is designed with low power electronic device. The research in the paper turns into a pre-exploration of commercialization of FSK signal detection instrumentation, and has important practical value.