Flux flow noise power spectra in the presence of local pinning interactions

1977 ◽  
Vol 28 (1-2) ◽  
pp. 83-93 ◽  
Author(s):  
F. Habbal ◽  
W. C. H. Joiner
Keyword(s):  
Power Spectra ◽  
Noise Power ◽  
Flux Flow ◽  
Flow Noise

Experimental and Theoretical Comparison of the Precision of Flame Atomic Absorption, Fluorescence, and Emission Measurements

1981 ◽  
Vol 35 (3) ◽  
pp. 317-324 ◽  
Author(s):  
N. W. Bower ◽  
J. D. Ingle
Keyword(s):  
Atomic Absorption ◽  
Flicker Noise ◽  
Power Spectra ◽  
Inner Filter Effect ◽  
Atomic Emission ◽  
Noise Power ◽  
Experimental Conditions ◽  
Noise Characteristics ◽  
Fluorescence Measurements ◽  
Flame Atomic Absorption

Theoretical equations and experimental evaluation procedures for the determination of the precision of flame atomic absorption, emission, and fluorescence measurements are presented. These procedures and noise power spectra are used to evaluate the precision and noise characteristics of atomic copper measurements with all three techniques under the same experimental conditions in an H2-air flame. At the detection limit, emission and fluorescence measurements are limited by background emission shot and flicker noise whereas absorption measurements are limited by flame transmission lamp flicker noise. Analyte flicker noise limits precision at higher analyte concentrations for all three techniques. Fluctutations in self-absorption and the inner filter effect are shown to contribute to the noise in atomic emission and fluorescence measurements.

scholarly journals Noise masking method based on an effective ratio mask estimation in Gammatone channels

2018 ◽  
Vol 7 ◽  
Author(s):  
Feng Bao ◽  
Waleed H. Abdulla
Keyword(s):  
Signal To Noise Ratio ◽  
Estimation Method ◽  
Wiener Filter ◽  
Power Spectra ◽  
Auditory Scene Analysis ◽  
Accurate Estimation ◽  
Noise Power ◽  
Noise Masking ◽  
Time Frequency ◽  
Mask Estimation

In computational auditory scene analysis, the accurate estimation of binary mask or ratio mask plays a key role in noise masking. An inaccurate estimation often leads to some artifacts and temporal discontinuity in the synthesized speech. To overcome this problem, we propose a new ratio mask estimation method in terms of Wiener filtering in each Gammatone channel. In the reconstruction of Wiener filter, we utilize the relationship of the speech and noise power spectra in each Gammatone channel to build the objective function for the convex optimization of speech power. To improve the accuracy of estimation, the estimated ratio mask is further modified based on its adjacent time–frequency units, and then smoothed by interpolating with the estimated binary masks. The objective tests including the signal-to-noise ratio improvement, spectral distortion and intelligibility, and subjective listening test demonstrate the superiority of the proposed method compared with the reference methods.

Thermopower and 1/f Noise Measurements in Amorphous Silicon-Carbon Alloys

1995 ◽  
Vol 377 ◽  
Author(s):  
H. M. Dyalsingh ◽  
G. M. Khera ◽  
J. Kakalios
Keyword(s):  
Amorphous Silicon ◽  
Power Spectra ◽  
Carbon Films ◽  
Noise Power ◽  
Mobility Edge ◽  
Silicon Carbon ◽  
Noise Measurements ◽  
Noise Statistics ◽  
Hydrogenated Amorphous ◽  
Q Function

ABSTRACTThermopower, conductivity and 1/f noise measurements have been performed on a series of n-type doped hydrogenated amorphous silicon carbon films that are prepared with varying gas phase concentrations of CH4. The increased disorder at the mobility edge associated with alloying is characterized by the Q-function, which is obtained by combining thermopower and conductivity measurements, and is also reflected in the noise power spectra and noise statistics.

Induced flux-flow noise in type II superconductors

Physica B+C ◽  
1976 ◽  
Vol 84 (2) ◽  
pp. 189-199
Author(s):  
H.M. Choe ◽  
A. Van der Ziel
Keyword(s):  
Type Ii ◽  
Flux Flow ◽  
Type Ii Superconductors ◽  
Flow Noise

Flux-flow noise in superconductors

1981 ◽  
Vol 75 (1) ◽  
pp. 1-55 ◽  
Author(s):  
John R. Clem
Keyword(s):  
Flux Flow ◽  
Flow Noise

Wiener noise power spectra of radiological television systems using a digital oscilloscope

1990 ◽  
Vol 17 (1) ◽  
pp. 58-64 ◽  
Author(s):  
J. A. Rowlands ◽  
G. DeCrescenzo
Keyword(s):  
Power Spectra ◽  
Noise Power ◽  
Digital Oscilloscope

Prediction of Ship Acoustic Signature Due to Fluid Flow

2007 ◽  
Author(s):  
Mae L. Seto ◽  
Rubens Campregher ◽  
Stefan Murphy ◽  
Julio Militzer
Keyword(s):  
Flow Field ◽  
Immersed Boundary ◽  
Noise Power ◽  
Far Field ◽  
Acoustic Analogy ◽  
Noise Component ◽  
Cavitation Inception ◽  
Flow Noise ◽  
Acoustic Signature ◽  
Acoustic Ranging

The contribution of flow noise to the radiated acoustic signature of CFAV Quest is of interest. Quest is the research ship used by Defence R&D Canada as a quiet platform. It is difficult to identify the flow noise component in an acoustic ranging so there is interest in predicting the flow noise as a first step towards extracting it from range measurements. Below propulsor cavitation inception speeds, machinery-induced noise dominates. While flow noise does not usually dominate in the presence of machinery-induced noise or propulsor cavitation, it is unclear what fraction of the total noise power flow noise constitutes. A direct numerical simulation for a complex ship geometry was impractical so an alternative approach was sought. An immersed boundary method was used to model the presence of the ship in the flow domain. The unsteady flow field was calculated using a finite volume method over an unstructured Cartesian grid. The flow field around Quest in straight and level flight was calculated at Reynolds numbers between 1.8×108 and 4.3×108, corresponding to a full-scale speed range of 4 to 10 knots. Results from such flow field predictions become the hydrodynamic sources in the integrals of Lighthill’s acoustic analogy to predict the far-field acoustic signature from the flow past the hull. These far-field predictions consist of computing the propagation and radiation of the hydrodynamic sources. This assumes noise generation and its propagation are decoupled. Under certain circumstances, knowledge of the predicted flow component helps to extract it from a standard acoustic ranging.

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