Dissertation > Excellent graduate degree dissertation topics show

The Measure and Control System of Fourier Spectrum Based on DSP

Author: ZhangJingBo
Tutor: WuHanHua
School: Jilin University
Course: Measuring Technology and Instruments
Keywords: Fourier Spectrometer FFT DSP
CLC: TH744.1
Type: Master's thesis
Year: 2005
Downloads: 272
Quote: 2
Read: Download Dissertation

Abstract

The Fourier transform spectrometer has been widely used in many fields such as agriculture, astronomy, automobile, biology, chemistry, etc.. The Fourier transform spectrum technology includes much knowledge such as optics, electronics, mathematics and computer science and so on. The traditional Fourier transform spectrometer based on Michelson interferometer is a time modulating spectrometer. This kind of spectrometer is very sensitively to shake because it produces the phase place by moving the mirror. So it has very high request to the measuring environment, this makes its application receive very great limitation. The space modulating static type Fourier transform spectrometer of has solved above-mentioned problems. And many institute study on it in the world at present. In order to get the spectrum information, first, the Fourier transform spectrometer changes interfering picture to disperse digital information and then make a Fourier transform. So the converting from interfering picture to electronic signal is an important link of Fourier transform spectrometer and digital signal processing is necessary. As the other measuring instruments, with the development of modern photoelectron technology and computer technology, Fourier transform spectrometer becomes more miniaturization, integrated and intelligent. The high integrated CCD device with wide spectrum responding range and high spectrum resolution is the mainly converting device from interfering picture to electronic signal of the static Fourier transform spectrometer. With wide application of CCD, people have thoroughly researched the method of CCD driven and CCD signal acquisition. But there isn’t a compact integrated signal acquisition and CCD driven system that is suitable for polarization interfere spectrometer. In order to find a good acquisition and driven system we must go on study. The quality of the digitization signal gathered from interfering picture directly influences the final resolution ratio of spectrum; the time of measurement is mainly decided by digital signal processing system. The CCD driven system and data acquisition system are separated with the process system in the early Fourier transform spectrometer. The data collecting card gathers the data and then the all-purpose computer finishes data processing. To make instrument miniaturization and intelligent require instrument can break away from general computer finish the work of treatment of datum independently. With the appearance of digital signal processor (DSP), realization this function become possible. At first, the thesis introduces the basic principle and characteristic of Fourier transform spectrum based on the Wollaston prism. Set up an essential theoretical foundation for the data process of the measure and control system. From the Fourier transform spectrometer principle we can know that interference picture and spectrogram of light source have Fourier transform relation. In theory, as long as sample the interference picture and make a Fourier transform, then can get the spectrogram of the light source. So, it is that the measure and control system of Fourier transform spectrometer has two key contents that are the sampling interference picture and process digital signal. On the basis of understanding static type Fourier transform spectrometer principle, we design a measure and control system which is best suitable for static Fourier transform spectrum. Then the thesis make an system study on the operation principle of CCD , driven technology, CCD video signal gathering method and the data process method. CCD is a kind of photoelectric coupling device, you must offer the appropriate time sequence pulse for it then CCD can finish the conversion from the optical signal to the electric signal. CCD time sequence signal control circuit usually has four kinds of realization ways: the digital circuit driven method, one-chip computer driven method, EPROM driven method and special-purpose IC drives method. Each of these methods has advantage and disadvantage. you should choose the suitable drive method according to different actual conditions. According to CCD sensor difference use, there are two kinds of process methods of CCD video signal: first, make the CCD video signal to two value one or zero and then gather the data ; second Change dispersed video signal into continuous voltage value and then

Related Dissertations

CLC: > Industrial Technology > Machinery and Instrument Industry > Instruments, meters > Optical instruments > Physical optical instruments > Spectrometers
© 2012 www.DissertationTopic.Net Mobile