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The Study On Signal Processing Method And Subdivision Technology Based On Diffraction Grating

Posted on:2016-06-08Degree:MasterType:Thesis
Country:ChinaCandidate:Y WangFull Text:PDF
GTID:2308330461477171Subject:Mechanical engineering
Abstract/Summary:PDF Full Text Request
With the progress of modern society, nano-technology, bio-medicine, semiconductor manufacturing and ultra-precision machining technology are developing rapidly in recent years. However, the micron level measurement methods are no longer meeting the requirement of fabrication. It is now need some measurement devices with higher resolution, higher speed but with smaller size. In the field of grating displacement sensor, the productions of foreign companies could achieve the highest resolution of picometer leve, but the resolution of the relevant domestic products are far less than them. As a result, it is extremely important for us to develop a kind of high-resolution processing method and subdivision technology for grating signal, in order to make up the domestic black for the modernization and scientific progresses of our country.In the first part of this paper, some theories such as Huygens principle, Doppler shift, interference between different frequencies and polarization optics were introduced. Besides, the Jones calculus of the optical path was derived and then it was proved that the path could obtain four sinusoidal optical signals with equal amplitudes and the phase between adjacent signal is 90 degree.A kind of pre-processing circuit for the optical signals was designed, which was aiming to reduce the adverse influences of amplitude errors, DC level shift and non-orthogonality of the signals.Secondly, the theories of the wavelet transform and the elliptic fitting compensation were studied to developed a program with the help of Lab VIEW and MATLAB. The program was designed to refine the quality of the subsequent used signal through largely removing the signal noise and then further improving orthogonality.Also, a variety of common used subdivision methods were introduced and analyzed their advantages and disadvantages. Based on the Lab VIEW, a high resolution subdivision signal program was achieved to process the collection signals.Finally, the actual signals were collected and pre-processed with the designed circuits and then subdivided by designed programs. At the end of this paper, the resolution of the subdivision results were analyzed and some advice were gave to improve it.
Keywords/Search Tags:Diffraction Grating, Subdivision, Wavelet Transform, Elliptic FittingCompensation
PDF Full Text Request
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