Autocorrelation spectral analysis has demonstrated excellent stability, flexibility, and noise floor levels in radio astronomy applications, largely due to its predominantly digital signal processing. Extending this approach to the wide bandwidths required in millimeter-wave stratospheric remote sensing requires advances in fast digital signal processing techniques. To reach a target bandwidth of 400 MHz requires an 800-MHz digitizer sample rate and processing throughput. We have produced in quantity the required delay-multiply-count digital building block (or node) operable above 400 MHz We have demonstrated logic of the speed required for the 800-MHz digitizer and the distributor which divides the data into multiple slower streams for processing by the node cascades, but have not yet completed these faster portions. The completed instrument will offer 2% spectral resolution to 400 MHz total instantaneous bandwidth, and 1% resolution for all total bandwidths below 200 MHz. Observation time penalty due to the 3-level signal representation used is 57%.
{"title":"A 400-MHz Bandwidth Autocorrelation Spectrum Analyzer","authors":"P. Ekstrom","doi":"10.1364/sam.1980.wp25","DOIUrl":"https://doi.org/10.1364/sam.1980.wp25","url":null,"abstract":"Autocorrelation spectral analysis has demonstrated excellent stability, flexibility, and noise floor levels in radio astronomy applications, largely due to its predominantly digital signal processing. Extending this approach to the wide bandwidths required in millimeter-wave stratospheric remote sensing requires advances in fast digital signal processing techniques. To reach a target bandwidth of 400 MHz requires an 800-MHz digitizer sample rate and processing throughput. We have produced in quantity the required delay-multiply-count digital building block (or node) operable above 400 MHz We have demonstrated logic of the speed required for the 800-MHz digitizer and the distributor which divides the data into multiple slower streams for processing by the node cascades, but have not yet completed these faster portions. The completed instrument will offer 2% spectral resolution to 400 MHz total instantaneous bandwidth, and 1% resolution for all total bandwidths below 200 MHz. Observation time penalty due to the 3-level signal representation used is 57%.","PeriodicalId":199214,"journal":{"name":"Topical Meeting on Spectroscopy in Support of Atmospheric Measurements","volume":"82 4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123240568","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
For several years Microwave Rotational Spectrometry (M.R.S.) has(1,2) shown promise of becoming a powerful analytic method for polar gases. The particular features of interest in M.R.S. are the very high specificity and linearity of response over a wide dynamic range. Because of the high specificity, it is possible to measure the concentrations of several gases by the same technique, in the same instrument, with a single sample. For example one can detect and quantify any one of many sulfur containing molecules (such as OCS, SO2, H2S, CH3SH, etc.) without regard to interferences. The wide range linear response provides an ease of calibration not found with most other techniques.
{"title":"Microwave Rotational Spectrometry in the Analysis of Trace Atmospheric Constituents","authors":"E. A. Rinehart, J. Harder","doi":"10.1364/sam.1980.tup13","DOIUrl":"https://doi.org/10.1364/sam.1980.tup13","url":null,"abstract":"For several years Microwave Rotational Spectrometry (M.R.S.) has(1,2) shown promise of becoming a powerful analytic method for polar gases. The particular features of interest in M.R.S. are the very high specificity and linearity of response over a wide dynamic range. Because of the high specificity, it is possible to measure the concentrations of several gases by the same technique, in the same instrument, with a single sample. For example one can detect and quantify any one of many sulfur containing molecules (such as OCS, SO2, H2S, CH3SH, etc.) without regard to interferences. The wide range linear response provides an ease of calibration not found with most other techniques.","PeriodicalId":199214,"journal":{"name":"Topical Meeting on Spectroscopy in Support of Atmospheric Measurements","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116820834","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Absolute absorption measurements were made on 172 selected lines in the near IR spectrum of H2O. Line strengths and N2 pressure broadening coefficients were determined with standard deviations in the range 1-5% for a majority of the lines. Self-broadening coefficients and pressure shifts were also measured for several lines. The line selection criteria were based on the requirements for remotely measuring atmospheric humidity profiles with narrow-band, tunable, pulsed lasers by means of light detection and ranging (lidar).
{"title":"Water Vapor Absorption Parameters For Selected Lines, 715-732nm And 932-961nm(1)","authors":"G. Schwemmer, B. Gentry, T. Wilkerson, L. Giver","doi":"10.1364/sam.1980.wp20","DOIUrl":"https://doi.org/10.1364/sam.1980.wp20","url":null,"abstract":"Absolute absorption measurements were made on 172 selected lines in the near IR spectrum of H2O. Line strengths and N2 pressure broadening coefficients were determined with standard deviations in the range 1-5% for a majority of the lines. Self-broadening coefficients and pressure shifts were also measured for several lines. The line selection criteria were based on the requirements for remotely measuring atmospheric humidity profiles with narrow-band, tunable, pulsed lasers by means of light detection and ranging (lidar).","PeriodicalId":199214,"journal":{"name":"Topical Meeting on Spectroscopy in Support of Atmospheric Measurements","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116252985","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The scientific objectives of the IRIS experiment of the Voyager 1 and 2 missions[1] (encounters with Jupiter in March and July 1979) are the study of the atmospheres of Jupiter, Saturn and possibly Uranus, from radiometric measurements in the infrared by means of a Michelson interferometer. For the first time, more than 50000 spectra of Jupiter were recorded with a spectral resolution of 4.3 cm-1.
{"title":"The Ammonia Infrared Absorption Reinvestigated in Connection with the Voyager Mission to Jupiter and Saturn","authors":"N. Husson, A. Chédin, N. Scott","doi":"10.1364/sam.1980.tup9","DOIUrl":"https://doi.org/10.1364/sam.1980.tup9","url":null,"abstract":"The scientific objectives of the IRIS experiment of the Voyager 1 and 2 missions[1] (encounters with Jupiter in March and July 1979) are the study of the atmospheres of Jupiter, Saturn and possibly Uranus, from radiometric measurements in the infrared by means of a Michelson interferometer. For the first time, more than 50000 spectra of Jupiter were recorded with a spectral resolution of 4.3 cm-1.","PeriodicalId":199214,"journal":{"name":"Topical Meeting on Spectroscopy in Support of Atmospheric Measurements","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130813974","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
For more than a year we have obtained monthly spectra of the earth s atmosphere in the 1.0-2.5μm region using the Fourier Transform Spectrometer (FTS) at the McMath Solar Telescope of Kitt Peak National Observatory. At the present time the spectra are obtained over a range of airmasses ranging between 1 and 10 airmasses. The individual spectra cover the entire 1.0-2.5μm region in a single observation with a resolution of 9.5 mK. The signal-to-noise ratios are generally greater than 1000 for all but the 10 airmass spectra.
{"title":"The PNL/KPNO Telluric Spectrum Program","authors":"G. Stokes, J. Brault, L. Testerman","doi":"10.1364/sam.1980.tup25","DOIUrl":"https://doi.org/10.1364/sam.1980.tup25","url":null,"abstract":"For more than a year we have obtained monthly spectra of the earth s atmosphere in the 1.0-2.5μm region using the Fourier Transform Spectrometer (FTS) at the McMath Solar Telescope of Kitt Peak National Observatory. At the present time the spectra are obtained over a range of airmasses ranging between 1 and 10 airmasses. The individual spectra cover the entire 1.0-2.5μm region in a single observation with a resolution of 9.5 mK. The signal-to-noise ratios are generally greater than 1000 for all but the 10 airmass spectra.","PeriodicalId":199214,"journal":{"name":"Topical Meeting on Spectroscopy in Support of Atmospheric Measurements","volume":"84 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116401135","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Theory of line shape will be discussed with emphasis on the relationship between observables and molecular parameters, including consideration of theoretical constraints.
线形理论将重点讨论可观测物与分子参数之间的关系，包括考虑理论约束。
{"title":"Line Widths and Shapes","authors":"S. Clough","doi":"10.1364/sam.1980.tub2","DOIUrl":"https://doi.org/10.1364/sam.1980.tub2","url":null,"abstract":"Theory of line shape will be discussed with emphasis on the relationship between observables and molecular parameters, including consideration of theoretical constraints.","PeriodicalId":199214,"journal":{"name":"Topical Meeting on Spectroscopy in Support of Atmospheric Measurements","volume":"70 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114825446","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A high resolution, 3 meter focal length grating spectrometer utilizing liquid nitrogen cooled order sorting optics has been developed for laboratory spectroscopy of atmospheric constituents in the 2 μm to 30 μm spectral region, the spectrometer uses a Littrow optical design modified to allow either two or four diffractions off the 25 cm echelle grating. The theoretical resolution is 0.011 cm−1 for double pass and 0.006 cm−1 for four pass operation. The fundamental limitation in achieving high resolution in infrared grating spectroscopy has been the problem of high noise associated with high room temperature background. In order to perform measurements with sufficient signal to noise, grating spectrometers must generally be operated with slit widths substantially greater than the diffraction limit. This results in an increase in signal but with a loss in resolution. In the near infrared, where relatively low blackbody background photon fluxes occur, spectrometers with resolutions as high as 0.015 cm−1 have been used. In the thermal infrared, however, the resolution of grating spectrometers has been limited to about 0.05 to 0.10 cm−1 by the high blackbody backgrounds occurring in this region.
{"title":"A Cooled Optics Spectrometer for High Resolution Measurements in Support of Atmospheric Research","authors":"L. Strow, C. Korb, B. Gentry","doi":"10.1364/sam.1980.tup21","DOIUrl":"https://doi.org/10.1364/sam.1980.tup21","url":null,"abstract":"A high resolution, 3 meter focal length grating spectrometer utilizing liquid nitrogen cooled order sorting optics has been developed for laboratory spectroscopy of atmospheric constituents in the 2 μm to 30 μm spectral region, the spectrometer uses a Littrow optical design modified to allow either two or four diffractions off the 25 cm echelle grating. The theoretical resolution is 0.011 cm−1 for double pass and 0.006 cm−1 for four pass operation. The fundamental limitation in achieving high resolution in infrared grating spectroscopy has been the problem of high noise associated with high room temperature background. In order to perform measurements with sufficient signal to noise, grating spectrometers must generally be operated with slit widths substantially greater than the diffraction limit. This results in an increase in signal but with a loss in resolution. In the near infrared, where relatively low blackbody background photon fluxes occur, spectrometers with resolutions as high as 0.015 cm−1 have been used. In the thermal infrared, however, the resolution of grating spectrometers has been limited to about 0.05 to 0.10 cm−1 by the high blackbody backgrounds occurring in this region.","PeriodicalId":199214,"journal":{"name":"Topical Meeting on Spectroscopy in Support of Atmospheric Measurements","volume":"76 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122199327","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The results presented here were obtained from interferograms recorded at an altitude of 40 km during the sunset period of the Stratoprobe VI balloon flight from Palestine, Texas (32°N latitude) on Nov. 8, 1978. The interferometer, built by Bomem Inc., has a resolution of 0.05 cm-1 un-apodized, and has been described by Buijs et al.(1980). For the Stratoprobe balloon flights series several modifications were made. A sun tracker was added to the instrument to improve the tracking provided by the solar table on the gondola. The installation of an electronic numerical filter reduced the data rate by a factor of 31, providing 5100 samples from each one-sided interferogram. The time required for one interferometer scan was 83 seconds. Interferograms were recorded in the 1840-1990 cm-1 and 2860-3000 cm-1 regions simultaneously.
{"title":"Methane Profiles at 32°N from Infrared Absorption Measurements on Project Stratoprobe","authors":"H. Fast, W. Evans, H. Buijs, G. Vail","doi":"10.1364/sam.1980.tup3","DOIUrl":"https://doi.org/10.1364/sam.1980.tup3","url":null,"abstract":"The results presented here were obtained from interferograms recorded at an altitude of 40 km during the sunset period of the Stratoprobe VI balloon flight from Palestine, Texas (32°N latitude) on Nov. 8, 1978. The interferometer, built by Bomem Inc., has a resolution of 0.05 cm-1 un-apodized, and has been described by Buijs et al.(1980). For the Stratoprobe balloon flights series several modifications were made. A sun tracker was added to the instrument to improve the tracking provided by the solar table on the gondola. The installation of an electronic numerical filter reduced the data rate by a factor of 31, providing 5100 samples from each one-sided interferogram. The time required for one interferometer scan was 83 seconds. Interferograms were recorded in the 1840-1990 cm-1 and 2860-3000 cm-1 regions simultaneously.","PeriodicalId":199214,"journal":{"name":"Topical Meeting on Spectroscopy in Support of Atmospheric Measurements","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125721675","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In recent years many studies have been focused on the problems associated with the infrared radiation observable in the upper atmosphere. Identification of the spectral features in the observed radiation is a key to improving our understanding of the physical and chemical processes in the upper atmosphere. In our laboratory experimental program we study the infrared emission features of various atmospheric species, atomic and molecular, using the technique of Fourier spectroscopy.
{"title":"Infrared Emission Spectroscopy of Atmospheric Atoms and Molecules*","authors":"Ron Johansson, Martti Peltola, H. Sakai","doi":"10.1364/sam.1980.wp12","DOIUrl":"https://doi.org/10.1364/sam.1980.wp12","url":null,"abstract":"In recent years many studies have been focused on the problems associated with the infrared radiation observable in the upper atmosphere. Identification of the spectral features in the observed radiation is a key to improving our understanding of the physical and chemical processes in the upper atmosphere. In our laboratory experimental program we study the infrared emission features of various atmospheric species, atomic and molecular, using the technique of Fourier spectroscopy.","PeriodicalId":199214,"journal":{"name":"Topical Meeting on Spectroscopy in Support of Atmospheric Measurements","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128995852","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Illustrations of the diverse approaches necessary for understanding excited states will be offered in discussions of spectra of NO, N2O, NO2, ClO2, O3 and H2CO.
{"title":"Spectroscopy of Electronically Excited States","authors":"K. Innes","doi":"10.1364/sam.1980.tua1","DOIUrl":"https://doi.org/10.1364/sam.1980.tua1","url":null,"abstract":"Illustrations of the diverse approaches necessary for understanding excited states will be offered in discussions of spectra of NO, N2O, NO2, ClO2, O3 and H2CO.","PeriodicalId":199214,"journal":{"name":"Topical Meeting on Spectroscopy in Support of Atmospheric Measurements","volume":"2011 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127372698","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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