Simulation Of Thickness Of Top Coal Detection And Singal Wavelet Analyzing Researchment

This thesis mainly focuses on two things, one is the simulation of the thickness of top coal detection, the other is the application on the modulus maximum of wavelet analysis,singal singularity and wavelet packet denoising. The main contents can be summarized as follows:As far as the simulation of the thickness of top coal detection, we discuss the principle and the method of thickness of the top coal detection by means of elastic wave, analyze the existing problems and put forward the corresponding solutions. After construct physics model , we undertake four kinds of simulation , that is the thickness of top coal is two meters, four meters, six meters and eight meters and conclude the condition of the wavelet main frequencies if we want to distinguish the reflected wave arriving point. As far as the first status, the wavelet main frequencies should be no less than 1200Hz, the second one is 700Hz, the third one is 500Hz and the last one is 400 Hz. At last, we compare the module result with the frequency of detected singal and put forward the requirment of focal.As far as the application of wavelet theory in the thickness of top coal detection, we bring forward the principle when choice the wavelet according to three problems. Utilizing the different expression form of signal and noise in different scales, we put the multiscale analysis theory into practical signal analyzing. Combining the theory of module maximum with the single's singularity and using the Matlab language , we identified the reflected wave's arriving point and computed the thickness of top coal. Comparing with the detection result, we can conclude that this method is feasible.Because we use the theory of module maximum in indentifing the reflected wave's arriving point, the resule can't be distinguished easily. At the same time, the resule is interfered by noise,so, we put the wavelet packet method into dispelling noise. Comparing with the two resules, we can see that the wavelet packet method is feasible and the result can be identified easily.Through the above discussment, we can conclude that in the thickness of top coal detection,elastic wave method is effective. If the focal satisfy the requirment of the frequency bnak and we take some measures on the emit and receive equipment and use advanced signal analysis method -wavelet analysis ,we can obtain ideal result .Using the wavelet theory in the thickness of top coal detection, the result's precision can be improved and the method has a wide development prospects .