Design Of Rail Ultrasound Guided Wave Commuication System Based On 2FSK

Under the influence of long-term work and external environment,rails are prone to damage or even breakage,which in turn affects train safety.Therefore,it is very important to be able to obtain the in-service rail damage information in real time by means of communication.The existing wireless communication methods mainly include digital transmission modules,mobile communication,etc.,but there are disadvantages such as signal dead zones in tunnels and the like,and the use of ultrasonic waves to realize communication in the rails can make up for the shortcomings.This paper designs a 2FSK rail ultrasonic guided wave communication system.First,the overall scheme of the system and the modulation and demodulation algorithm are designed.In order to increase the transmission efficiency of the ultrasonic transducer,the two carrier frequencies of the system are selected near the center frequency of the transducer.On this basis,the paper completes the software and hardware design of the system.The system includes the transmitter module and the receiver module.in order to improve the signal energy of the transmitting end,the original transducer driving circuit of the laboratory is improved by a full-bridge pulse driving method,and a wake absorption circuit is added to reduce the high frequency tailing of the excitation signal.The receiving end demodulation circuit adopts a non-coherent demodulation method.The received signal is processed by a preamplifier circuit,a bandpass filter circuit,a Schmitt shaping circuit,and a level shift circuit,and then the signal is demodulated by the STM32 microcontroller.Finally,the correctness of the communication function is verified by the system joint debugging.After the system design is completed,a 100-meter ultrasonic communication experiment is completed on the railway site.Through a large number of experiments,the communication rate of the system is 800bps and the bit error rate is 0.008.It can realize low-rate communication in the rail,which provides a reference for the communication of ultrasonic waves in the rail.