| Optical fiber vibration sensing technology can be used for disturbance monitoring in long and continuous region, based on the sensitivity and transmission characteristics which help sensing the vibration signal timely. To meet the need of wiring access technology and products in optical communication industry for Nanjing Putian telecommunication Co., Ltd in next decade, the data processing technology is studied in power/time division multiplexing regional optical fiber vibration sensing system taking the engineering application system development needs and scientific research projects as the goal.Firstly the sensing mechanism and the inhibiting effect for temperature and graded strain in Sagnac fiber interference vibration are analyzed. The frame of the power/time division multiplexing regional optical fiber vibration sensing system and its requirement for data signal processing are also introduced, based on which the scheme for data signal processing sub-system is presented. Successively, the scheme for data transmission module in data signal processing sub-system is proposed, based on which the data transmission between FPGA-USB-PC is established. The USB firmware program is designed. The interface communication between USB and PC is achieved on data processing card. The transmission of data block in the double cache is achieved, as well as the transmission of the control command and status. Then, the demodulate method which use a characteristic value characterizing the pulse signal to achieve pulse carrier signal without filtering demodulation is proposed. In this method, clock reference value is as a feature extraction reference. At the same time, the demultiplexing method is presented which adds header and flag in the pulse characteristic value to achieve the regional pulse signal demultiplexing. Lastly, the data processing software is debugged in the power/time division multiplexing regional fiber-optic vibration sensing experiment and live demonstration systems. System command and data transmission and data processing of the sub-system are verified successfully. The transmission of command and data is verified successfully, as well as the function of data processing sub-system. The results show that the transmission of the data blocks and orders are function normally, and so are the self-test of the number and the position of regions. At the same time, the demodulation and demultiplexing of data, addressing vibration signal, the configuration of parameter, detection of broken fiber and other functions in the data processing subsystem worked properly. The system can detect the disturbance signals in real-time and determin the location of the disturbance event area accurately to meet the needs of users. |
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