Spectral noise due to sampling errors in Fourier-transform spectroscopy

Year: 2001

Authors: Palchetti L., Lastrucci D.

Autors Affiliation: Istituto di Ricerca sulle Onde Elettromagnetiche “Nello Carrara, Consiglio Nazionale delle Ricerche, Via Panciatichi 64, Firenze, I-50127, Italy

Abstract: An assessment is made of the spectral noise in Fourier-transform spectroscopy caused by sampling errors in the interferogram acquisition. Numerical evaluations are performed in the case of the REFIR (radiation explorer in the far infrared) instrument developed for the measurement of the long-wavelength Earth emissions from satellite platforms. In this case the slow response of a room-temperature pyroelectric detector, the relatively short acquisition time, the broadband operation, and the wish for a relaxed requirement of the mirror drive accuracy make sampling error an important issue. Different sampling methods can be considered for reduction of the spectral noise induced by sampling errors. The effects of different sampling methods are quantified and discussed for the selection of the most-suitable option for this instrument. We find that only sampling methods that introduce some compensation (either analog or digital) of the frequency dependence of amplitude and phase components of the acquisitionsystem responsivity provide satisfactory results. In particular, the equal time sampling followed by a digital filter and numerical resampling has been examined minutely with a simulation model used to perform sensitivity tests of the main parameters that characterize the procedure.

Journal/Review: APPLIED OPTICS

Volume: 40 (19)      Pages from: 3235  to: 3243

KeyWords: Digital filters; Error analysis; Mirrors; Radiation; Sampling; Satellites, Spectral noise, Fourier transform infrared spectroscopy
DOI: 10.1364/AO.40.003235

Citations: 30
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