The Development Of Low Rectangle Coefifcient Filter In MRS System For Advance Exploration

In the underground resources mining, underground tunnel construction andtunnel construction, water inrush disasters occur most frequently and most severelydamaged of geological disasters. The sudden water-related disasters has become thebottleneck restricting the underground works, tunnels construction. MRS refers to thespecific frequency of the alternating electromagnetic field to stimulate the nuclei, sothat resonant transitions between energy levels. Because the initial amplitude of theMRS and the free water within the detection range of the number of hydrogen nucleiis proportional to that and the water content is proportional to geologic body, it can beused to detect the tunnel in front of free water exists, and the specific water content.The disaster water advance detection in the underground mine/tunnel has a verypractical significance. The method not only can effectively pre sentence in front ofwater situation, to prevent the accident of water gushing phenomenon, improve thesafety of underground engineering, can also enhance the efficiency of progress inunderground engineering, is of epoch-making significance in geological explorationindustry.MRS tunnel advance detector is very sensitive. In the mine/tunnel, theinterference and noise is extremely complex. It has caused great distress to the signalacquisition. This paper has designed a narrowband filter whose center frequency andbandwidth is tunable to filtering, then through the programmable gain amplifier in theend, and adjust the signal within the range of MRS signal detector. Innovative usesthe thinking of switch capacitor and numerical control potentiometer, implements thecontinuous adjustment of Q value. Overcome the shortcoming on the Q valueadjusting of MAX260step over too much; Reference to the thought of jagged filterdesign, this design reduced the rectangular coefficient filter effectively and improve the selectivity of filter. The anti-interference ability has been improved. And thedesign improved the SNR of the detector to make the result accurate.The thesisconsists of six chapters, each chapter is as follows:Chapter one is the exordium of this paper. It contains: the background andsignificance of the research on MRS; current progress and trend at home and abroad;and pointed out that the emphasis of this paper.Chapter two introduces the theory of the MRS tunnel advance detection; thestructure and working process of MRS tunnel advance detector; clear the detectiondifficulties of the detector.Chapter three introduces the way of filtering according to the filtering principle,derives the theoretical formula of narrowband filter, summarizes the design method oflow rectangle coefficient programmable filter.Chapter four describes the simulation of low rectangle coefficient programmablefilter system, and makes the analysis of the simulation results.Chapter five introduces the design scheme and realization of the low rectanglecoefficient of programmable filter, includes the design target, design scheme, specifichardware design and software design.Chapter six contains the indoor test, outdoor test and field test of low rectanglecoefficient programmable filter. And analyses the experimental results obtained.Chapter seven summarizes the whole paper and puts forward some suggestionsfor further improvement.After a large number of experimental tests, the performance of low rectanglecoefficient programmable filter of the MRS tunnel advance detector achieves thetarget, the performance of each module is stable, rectangular coefficient of filteringsystem is low, the filtering system has good selectivity. Accumulates data andexperience for the latter instrument anti-interference performance improvement, andlays the foundation for the further promotion of instrument performance.