Signal-to-noise ratio in higher order derivative spectrometry

1981 ◽  
Vol 53 (12) ◽  
pp. 1876-1878 ◽  
Author(s):  
T. C. O'Haver ◽  
T. Begley
Keyword(s):  
Signal To Noise Ratio ◽  
Higher Order ◽  
Order Derivative ◽  
Signal To Noise ◽  
Higher Order Derivative ◽  
Noise Ratio ◽  
Derivative Spectrometry

Signal-to-noise ratio estimation using higher-order moments

2006 ◽  
Vol 86 (4) ◽  
pp. 716-732 ◽  
Author(s):  
S. Chandra Sekhar ◽  
T.V. Sreenivas
Keyword(s):  
Signal To Noise Ratio ◽  
Higher Order ◽  
Ratio Estimation ◽  
Signal To Noise ◽  
Higher Order Moments ◽  
Noise Ratio

A Bispectral Analysis of the Radio Emissions of Pulsar J0437-4715

2020 ◽  
Vol 09 (04) ◽  
pp. 2050018
Author(s):  
Alexander Faustmann ◽  
Jacki Gilmore ◽  
Vereese van Tonder ◽  
Maciej Serylak
Keyword(s):  
Signal To Noise Ratio ◽  
Gaussian Model ◽  
Higher Order ◽  
Detection Methods ◽  
High Signal ◽  
Signal To Noise ◽  
Noise Ratio ◽  
Alternative Detection ◽  
Higher Order Spectra

A combination of the very low signal-to-noise ratio and the very large parameter space spanned by pulsar emissions makes pulsar detection a challenging task. Currently, brute force parameter searches are often used for pulsar detection and a cyclostationary Gaussian model is assumed for pulsar emissions. Higher-Order spectra offer high signal-to-noise ratio domains in problems where the desired signal is polluted by Gaussian noise. The presence of nonzero higher-order spectral components in pulsar bursts may offer alternative detection methods. This work presents a review of higher-order statistics and offers a motivation for their use in the characterization of pulsar bursts. A dish from the MeerKAT telescope was used to acquire recorded radio bursts from pulsar J0437-4715. These bursts were found to contain nonzero bispectral components that were dispersed in the same way as the components of the power spectrum.

scholarly journals Higher-Order Amplitude Squeezing in Six-Wave Mixing Process

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
Sunil Rani ◽  
Jawahar Lal ◽  
Nafa Singh
Keyword(s):  
Fundamental Mode ◽  
Signal To Noise Ratio ◽  
Photon Number ◽  
Higher Order ◽  
Field Amplitude ◽  
Fourth Power ◽  
Wave Mixing ◽  
Mixing Process ◽  
Signal To Noise ◽  
Noise Ratio

We investigate theoretically the generation of squeezed states in spontaneous and stimulated six-wave mixing process quantum mechanically. It has been found that squeezing occurs in field amplitude, amplitude-squared, amplitude-cubed, and fourth power of field amplitude of fundamental mode in the process. It is found to be dependent on coupling parameter “g” (characteristics of higher-order susceptibility tensor) and phase values of the field amplitude under short-time approximation. Six-wave mixing is a process which involves absorption of three pump photons and emission of two probe photons of the same frequency and a signal photon of different frequency. It is shown that squeezing is greater in a stimulated interaction than the corresponding squeezing in spontaneous process. The degree of squeezing depends upon the photon number in first and higher orders of field amplitude. We study the statistical behaviour of quantum field in the fundamental mode and found it to be sub-Poissonian in nature. The signal-to-noise ratio has been studied in different orders. It is found that signal-to-noise ratio is higher in lower orders. This study when supplemented with experimental observations offers possibility of improving performance of many optical devices and optical communication networks.

scholarly journals Prediction of signal‐to‐noise ratio gain for passive higher‐order correlation detection of energy transients

1995 ◽  
Vol 98 (1) ◽  
pp. 248-260 ◽  
Author(s):  
Lisa A. Pflug ◽  
George E. Ioup ◽  
Juliette W. Ioup ◽  
Robert L. Field
Keyword(s):  
Signal To Noise Ratio ◽  
Higher Order ◽  
Signal To Noise ◽  
Noise Ratio

Determination of the Best Emulsion for the Microscopy of Crystals

1981 ◽  
Vol 39 ◽  
pp. 32-33
Author(s):  
David A. Grano ◽  
Kenneth H. Downing
Keyword(s):  
Spatial Frequency ◽  
Information Transfer ◽  
Signal To Noise Ratio ◽  
Experimental Situation ◽  
Photographic Emulsion ◽  
Modulation Transfer ◽  
Signal To Noise ◽  
Frequency Space ◽  
Noise Ratio

The retrieval of high-resolution information from images of biological crystals depends, in part, on the use of the correct photographic emulsion. We have been investigating the information transfer properties of twelve emulsions with a view toward 1) characterizing the emulsions by a few, measurable quantities, and 2) identifying the “best” emulsion of those we have studied for use in any given experimental situation. Because our interests lie in the examination of crystalline specimens, we've chosen to evaluate an emulsion's signal-to-noise ratio (SNR) as a function of spatial frequency and use this as our critereon for determining the best emulsion.The signal-to-noise ratio in frequency space depends on several factors. First, the signal depends on the speed of the emulsion and its modulation transfer function (MTF). By procedures outlined in, MTF's have been found for all the emulsions tested and can be fit by an analytic expression 1/(1+(S/S0)2). Figure 1 shows the experimental data and fitted curve for an emulsion with a better than average MTF. A single parameter, the spatial frequency at which the transfer falls to 50% (S0), characterizes this curve.

Experiments in Bright-Field Imaging with Hollow-Cone Illumination

1981 ◽  
Vol 39 ◽  
pp. 226-227
Author(s):  
W. Kunath ◽  
K. Weiss ◽  
E. Zeitler
Keyword(s):  
Signal To Noise Ratio ◽  
Carbon Support ◽  
Electronic System ◽  
Optic Axis ◽  
Hollow Cone ◽  
Signal To Noise ◽  
Bright Field ◽  
Noise Ratio ◽  
Single Field ◽  
Field Imaging

Bright-field images taken with axial illumination show spurious high contrast patterns which obscure details smaller than 15 ° Hollow-cone illumination (HCI), however, reduces this disturbing granulation by statistical superposition and thus improves the signal-to-noise ratio. In this presentation we report on experiments aimed at selecting the proper amount of tilt and defocus for improvement of the signal-to-noise ratio by means of direct observation of the electron images on a TV monitor.Hollow-cone illumination is implemented in our microscope (single field condenser objective, Cs = .5 mm) by an electronic system which rotates the tilted beam about the optic axis. At low rates of revolution (one turn per second or so) a circular motion of the usual granulation in the image of a carbon support film can be observed on the TV monitor. The size of the granular structures and the radius of their orbits depend on both the conical tilt and defocus.

Information capacity and bandwidth limitations in the SEM

1989 ◽  
Vol 47 ◽  
pp. 84-85
Author(s):  
D. C. Joy ◽  
R. D. Bunn
Keyword(s):  
Signal To Noise Ratio ◽  
Critical Dimension ◽  
Information Capacity ◽  
Acquisition Time ◽  
Signal To Noise ◽  
Sem Image ◽  
Probe Size ◽  
Minimum Number ◽  
Noise Ratio ◽  
Signal Channel

The information available from an SEM image is limited both by the inherent signal to noise ratio that characterizes the image and as a result of the transformations that it may undergo as it is passed through the amplifying circuits of the instrument. In applications such as Critical Dimension Metrology it is necessary to be able to quantify these limitations in order to be able to assess the likely precision of any measurement made with the microscope.The information capacity of an SEM signal, defined as the minimum number of bits needed to encode the output signal, depends on the signal to noise ratio of the image - which in turn depends on the probe size and source brightness and acquisition time per pixel - and on the efficiency of the specimen in producing the signal that is being observed. A detailed analysis of the secondary electron case shows that the information capacity C (bits/pixel) of the SEM signal channel could be written as :

Speech Reception in the Presence of Classroom Noise

1979 ◽  
Vol 10 (4) ◽  
pp. 221-230 ◽  
Author(s):  
Veronica Smyth
Keyword(s):  
Signal To Noise Ratio ◽  
Learning Processes ◽  
Speech Discrimination ◽  
Signal To Noise ◽  
Speech Reception ◽  
Monosyllabic Words ◽  
Noise Ratio

Three hundred children from five to 12 years of age were required to discriminate simple, familiar, monosyllabic words under two conditions: 1) quiet, and 2) in the presence of background classroom noise. Of the sample, 45.3% made errors in speech discrimination in the presence of background classroom noise. The effect was most marked in children younger than seven years six months. The results are discussed considering the signal-to-noise ratio and the possible effects of unwanted classroom noise on learning processes.

Quantifying the Effects of Background Speech Babble on Preschool Children's Novel Word Learning in a Multisession Paradigm: A Preliminary Study

2020 ◽  
Vol 63 (1) ◽  
pp. 345-356
Author(s):  
Meital Avivi-Reich ◽  
Megan Y. Roberts ◽  
Tina M. Grieco-Calub
Keyword(s):  
Word Learning ◽  
Signal To Noise Ratio ◽  
Preschool Age ◽  
Exposure Condition ◽  
Signal To Noise ◽  
Verbal Recall ◽  
Referent Selection ◽  
Main Effect ◽  
Noise Ratio ◽  
Novel Word Learning

Purpose This study tested the effects of background speech babble on novel word learning in preschool children with a multisession paradigm. Method Eight 3-year-old children were exposed to a total of 8 novel word–object pairs across 2 story books presented digitally. Each story contained 4 novel consonant–vowel–consonant nonwords. Children were exposed to both stories, one in quiet and one in the presence of 4-talker babble presented at 0-dB signal-to-noise ratio. After each story, children's learning was tested with a referent selection task and a verbal recall (naming) task. Children were exposed to and tested on the novel word–object pairs on 5 separate days within a 2-week span. Results A significant main effect of session was found for both referent selection and verbal recall. There was also a significant main effect of exposure condition on referent selection performance, with more referents correctly selected for word–object pairs that were presented in quiet compared to pairs presented in speech babble. Finally, children's verbal recall of novel words was statistically better than baseline performance (i.e., 0%) on Sessions 3–5 for words exposed in quiet, but only on Session 5 for words exposed in speech babble. Conclusions These findings suggest that background speech babble at 0-dB signal-to-noise ratio disrupts novel word learning in preschool-age children. As a result, children may need more time and more exposures of a novel word before they can recognize or verbally recall it.

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