scholarly journals Signal-to-Noise Ratio and Astronomical Fourier Transform Spectroscopy

1988 ◽  
Vol 132 ◽  
pp. 71-78
Author(s):  
J. P. Maillard
Keyword(s):  
Fourier Transform ◽  
Signal To Noise Ratio ◽  
Resolving Power ◽  
High Resolution Spectroscopy ◽  
Signal To Noise ◽  
Array Detectors ◽  
Noise Ratio ◽  
The Fourier Transform ◽  
Large Telescopes ◽  
Very High

The multiplex properties of the Fourier Transform Spectrometer (FTS) can be considered as disadvantageous with modern detectors and large telescopes, the dominant noise source being no longer in most applications the detector noise. Nevertheless, a FTS offers a gain in information and other instrumental features remain: flexibility in choosing resolving power up to very high values, large throughput, essential in high–resolution spectroscopy with large telescopes, metrologic accuracy, automatic substraction of parasitic background. The signal–to–noise ratio in spectra can also be improved: by limiting the bandwidth with cold filters or even cold dispersers, by matching the instrument to low background foreoptics and high–image quality telescopes. The association with array detectors provides the solution for the FTS to regain its full multiplex advantage.

scholarly journals A High-Resolution Dyadic Transform for Non-Stationary Signal Analysis

Mathematics ◽  
2021 ◽  
Vol 9 (23) ◽  
pp. 3041
Author(s):  
Eduardo Trutié-Carrero ◽  
Diego Seuret-Jimenez ◽  
José M. Nieto-Jalil
Keyword(s):  
Fourier Transform ◽  
Wavelet Transform ◽  
Signal Analysis ◽  
Signal To Noise Ratio ◽  
Signal To Noise ◽  
Dyadic Wavelet ◽  
Dyadic Wavelet Transform ◽  
Noise Ratio ◽  
The Fourier Transform ◽  
Non Stationary Signal

This article shows a new Te-transform and its periodogram for applications that mainly exhibit stochastic behavior with a signal-to-noise ratio lower than −30 dB. The Te-transform is a dyadic transform that combines the properties of the dyadic Wavelet transform and the Fourier transform. This paper also provides another contribution, a corollary on the energy relationship between the untransformed signal and the transformed one using the Te-transform. This transform is compared with other methods used for the analysis in the frequency domain, reported in literature. To perform the validation, the authors created two synthetic scenarios: a noise-free signal scenario and another signal scenario with a signal-to-noise ratio equal to −69 dB. The results show that the Te-transform improves the sensitivity in the frequency spectrum with respect to previously reported methods.

scholarly journals The Most Efficient Tool for very High Resolution and very High Signal to Noise Ratio Spectral Observation of Stars

1988 ◽  
Vol 132 ◽  
pp. 15-21
Author(s):  
S. Y. Jiang
Keyword(s):  
High Efficiency ◽  
Signal To Noise Ratio ◽  
Spectral Observation ◽  
Resolving Power ◽  
High Signal ◽  
Large Telescope ◽  
Signal To Noise ◽  
Noise Ratio ◽  
Very High ◽  
Light Efficiency

Today even for the most efficient spectrograph combined with a large telescope the light efficiency is only about 0.01 to 0.1 for spectral resolving power R larger than 10000 in optical wavelength band (OWB). Consequently for a very high signal to noise ratio spectral observation of rather bright stars still needs very large telescope. The main reason is that there are too many optical surface with rather low light efficiency and serious light loss at the limited slit width. In this paper we suggest a very high efficiency telescope-spectrograph system which will give an overall light efficiency varied from 0.21 at 400 nm to 0.44 at 700 nm, four fold higher than before. Using this system for R = 100000, S/N larger than 100 the limiting magnitude will be about 15.

Analytical model for the signal-to-noise-ratio of drift tube ion mobility spectrometers

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Ansgar T. Kirk ◽  
Alexander Bohnhorst ◽  
Stefan Zimmermann
Keyword(s):  
Ion Mobility ◽  
Drift Tube ◽  
Signal To Noise Ratio ◽  
Resolving Power ◽  
Operating Point ◽  
Optimum Operating ◽  
Signal To Noise ◽  
Experimental Parameters ◽  
Noise Ratio ◽  
Optimum Operating Point

Abstract While the resolving power of drift tube ion mobility spectrometers has been studied and modelled in detail over the past decades, no comparable model exists for the signal-to-noise-ratio. In this work, we develop an analytical model for the signal-to-noise-ratio of a drift tube ion mobility spectrometer based on the same experimental parameters used for modelling the resolving power. The resulting holistic model agrees well with experimental results and allows simultaneously optimizing both resolving power and signal-to-noise-ratio. Especially, it reveals several unexpected relationships between experimental parameters. First, even though reduced initial ion packet widths result in fewer injected ions and reduced amplifier widths result in more noise, the resulting shift of the optimum operating point when reducing both simultaneously leads to a constant signal-to-noise-ratio. Second, there is no dependence of the signal-to-noise-ratio at the optimum operating point on the drift length, as again the resulting shift of the optimum operating point causes all effects to compensate each other.

scholarly journals A New Multichannel Fourier Transform Spectrometer

1999 ◽  
Vol 170 ◽  
pp. 36-40
Author(s):  
Tyler E. Nordgren ◽  
Arsen R. Hajian
Keyword(s):  
Fourier Transform ◽  
Extrasolar Planets ◽  
Signal To Noise Ratio ◽  
Fourier Transform Spectrometer ◽  
Test Bed ◽  
Signal To Noise ◽  
Stellar Spectra ◽  
Band Emission ◽  
Noise Ratio ◽  
Ratio Scales

AbstractStellar spectra have been obtained using a multichannel Fourier Transform Spectrometer (FTS) which incorporates components of the Navy Prototype Optical Interferometer. It is well known that a FTS can provide superior wavelength stability as compared to traditional spectrometers. Unfortunately the FTS traditionally suffers from exceptionally poor sensitivity, which until now has limited its uses to sources with high fluxes and/or those with narrow band emission (e.g. the Sun, nebulae, and laboratory samples). We present stellar observations using a new FTS design which overcomes this sensitivity limitation by using a conventional multichannel spectrometer in conjunction with the FTS system. The signal-to-noise ratio of spectra from our test-bed observations are consistent with the theoretical prediction and show that for N channels the sensitivity scales like N, while the signal-to-noise ratio scales like . With this type of an instrument on a 3-m telescope and 9 000 channels we expect to be able to detect and measure such exciting astrophysical phenomenon as gravitational redshifts from single, main sequence stars and extrasolar planets of terrestrial mass.

Sign in / Sign up

Export Citation Format

Share Document