| The subject in this thesis was originated from the fourth batch of technical innovation projects in Shandong Province in 2012. The project was applied to monitor fully-mechanized face in xuchang coal mine of zibo mining group. The system was used in 1335 fully-mechanized face of xuchang coal mine in 2014 successfully.Firstly, the principle, operating environment, advantages and disadvantages of broadband power line carrier communication was introduced. The properties of PLC channel noise were deeply analyzed. In order to understand the characteristics of power line better, uniform transmission line and two-port network theory were used to build model. With the help of MATLAB, this paper analyzed the influence on high frequency voltage signal transmission and voltage signal due to the line distance and line terminal load impedance.Secondly, some key technologies of OFDM were introduced, such as the orthogonality of the digital signal, modulation-demodulation technique, guard interval technology with cyclic prefix, characteristics of peak-to-average power ratio(PAPR) and its suppression technology using limiting amplitude wave filter. Then the analysis graphs were given by MATLAB.Finally, a broadband power line carrier communication system was designed. STM32F107VCT6 with ARM Cortex-M3 was used in the system as a control core. The modulation-demodulation processor adopted the INT5130 chip which was produced by Intel Corporation. Aimed at receiving circuit and amplification circuit, the detailed analysis were given. Software process flow charts were given in the software part.The real-time transmission of borehole operation video signal was realized in real system. The system overcame many shortcomings such as construction difficult, system unstable and maintenance difficult because of devices move in borehole. It has great significance in promoting the construction of safety mines. And it has certain practicability and popularization value. |
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