CONTROL AND DATA ACQUISITION FOR A HIGH RESOLUTION DYNAMIC FOURIER TRANSFORM SPECTROMETER

Persistent Link:
http://hdl.handle.net/10150/282043
Title:
CONTROL AND DATA ACQUISITION FOR A HIGH RESOLUTION DYNAMIC FOURIER TRANSFORM SPECTROMETER
Author:
McCurnin, Thomas William, 1931-
Issue Date:
1981
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
A Fourier Transform Spectrometer (FTS) is an interferometric instrument configured so that the optical spectrum of the input to the instrument can be determined from the Fourier transform of the output. Spectral resolution is proportional to the maximum path differences in the interferometer. The Kitt Peak 1-Meter FTS is a high resolution instrument featuring a one-meter maximum path difference. The instrument is of the continuous motion type and utilizes equal time sampling of the interferogram. Realization of the potential of a one-meter path difference instrument requires very precise path difference positioning. Static and dynamic position accuracies of approximately seven Angstrom units are achieved in this instrument. Path difference command and control is accomplished through use of phase-lock techniques. A key element in the implementation is a Zeeman frequency stabilized Zeeman laser. Stabilization is accomplished by phase-locking the Zeeman frequency to a quartz crystal controlled system reference frequency. Path position information is derived by a control position interferometer which utilizes the Zeeman laser so that one cycle in phase at the Zeeman frequency corresponds to one wavelength in path difference at the laser optical frequency. Position control is achieved by phase-locking the output of the position control interferometer to a command signal. The command signal is synthesized from the laser Zeeman frequency by an additional phase-lock loop. Two approaches to minimizing spectral ghosts resulting from velocity errors are developed. One technique is applicable to band-pass designs. The second optimizes response of low-pass designs that include a single high-pass pole to reject the average value of the interferogram. Both techniques result in ghost responses improved by factors of at least ten to one-hundred compared with those of conventional data filters. The instrument includes an autoranging analog-to-digital converter with fifteen bits of resolution and total range of twenty-two bits developed to cope with the large dynamic range of the interferogram. These efforts together with careful design and construction have resulted in a powerful instrument which is in active use.
Type:
text; Dissertation-Reproduction (electronic)
Keywords:
Fourier transform spectroscopy.
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Graduate College; Electrical Engineering
Degree Grantor:
University of Arizona
Advisor:
Schooley, Larry C.

Full metadata record

DC FieldValue Language
dc.language.isoen_USen_US
dc.titleCONTROL AND DATA ACQUISITION FOR A HIGH RESOLUTION DYNAMIC FOURIER TRANSFORM SPECTROMETERen_US
dc.creatorMcCurnin, Thomas William, 1931-en_US
dc.contributor.authorMcCurnin, Thomas William, 1931-en_US
dc.date.issued1981en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractA Fourier Transform Spectrometer (FTS) is an interferometric instrument configured so that the optical spectrum of the input to the instrument can be determined from the Fourier transform of the output. Spectral resolution is proportional to the maximum path differences in the interferometer. The Kitt Peak 1-Meter FTS is a high resolution instrument featuring a one-meter maximum path difference. The instrument is of the continuous motion type and utilizes equal time sampling of the interferogram. Realization of the potential of a one-meter path difference instrument requires very precise path difference positioning. Static and dynamic position accuracies of approximately seven Angstrom units are achieved in this instrument. Path difference command and control is accomplished through use of phase-lock techniques. A key element in the implementation is a Zeeman frequency stabilized Zeeman laser. Stabilization is accomplished by phase-locking the Zeeman frequency to a quartz crystal controlled system reference frequency. Path position information is derived by a control position interferometer which utilizes the Zeeman laser so that one cycle in phase at the Zeeman frequency corresponds to one wavelength in path difference at the laser optical frequency. Position control is achieved by phase-locking the output of the position control interferometer to a command signal. The command signal is synthesized from the laser Zeeman frequency by an additional phase-lock loop. Two approaches to minimizing spectral ghosts resulting from velocity errors are developed. One technique is applicable to band-pass designs. The second optimizes response of low-pass designs that include a single high-pass pole to reject the average value of the interferogram. Both techniques result in ghost responses improved by factors of at least ten to one-hundred compared with those of conventional data filters. The instrument includes an autoranging analog-to-digital converter with fifteen bits of resolution and total range of twenty-two bits developed to cope with the large dynamic range of the interferogram. These efforts together with careful design and construction have resulted in a powerful instrument which is in active use.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.subjectFourier transform spectroscopy.en_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.disciplineElectrical Engineeringen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorSchooley, Larry C.en_US
dc.identifier.proquest8203734en_US
dc.identifier.oclc8705449en_US
dc.identifier.bibrecord.b13912446en_US
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