| The coal mine as the primary energy in our country, is national economy vitals. In the strong noise environment taking the coal mine as representative, the radio wave has encountered the very major difficulty in laneway when it transmits, but the mine mobile communication is shouldering important task as production, security and dispatch.It became a problem that how to realize reliable communication in the strong noise environment. The author proposed a scheme that applying the spread spectrum (SS) communication to the strong noise environment to solve this problem.The SS communication is a system that the spectrum of signal is spreaded in a wide frequency band when transmitted, and is recovered by the correlation reception when received. The SS communication, as an effective mode,is widely used in the martial and civil domain by its stronger anti-jamming ability.The main reason why the SS communication can pick up weak signal in the strong noise environment, is the function of spreading and despreading spectrum. Spreading and despreading spectrum is the basis of the system, but the key is the pseudonoise sequences. This article solved one of main problems is the generation and comparison of correlation property of pseudonoise sequences.It discussed the m-sequences,gold-sequences and balanced gold-sequences and designed MATLAB procedure. Mass datas and graphs produced by MATLAB has analysed the property of generation and correlation.It has drawn a helpful conclusion, and laid a foundation for the system design.At last,the article has proposed a scheme which can realize digital communication system in coal mine, and has established baseband receiving and transmitting system of SS.Then the author has completed the overall design and the internal module design and simulation,which is based on the Max+plus II by hiberarchy design method.The top floor schematic diagram is given.Finally it has realized this system function by the FPGA communication experimental equipment. |
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