scholarly journals Noise of short-time integrators for readout of uncooled infrared bolometer arrays

2010 ◽  
Vol 8 ◽  
pp. 129-133
Author(s):  
D. Würfel ◽  
D. Weiler ◽  
B. J. Hosticka ◽  
H. Vogt
Keyword(s):  
Transfer Functions ◽  
Noise Analysis ◽  
Far Infrared ◽  
Noise Sources ◽  
Readout Circuits ◽  
Time Integrators ◽  
Noise Equivalent Temperature Difference ◽  
Short Time ◽  
Bolometer Arrays ◽  
Key Parameter

Abstract. As state-of-the-art readout circuits short-time integrators in Far Infrared (FIR) uncooled bolometer arrays are commonly used. This paper compares the transfer functions of an ideal continuous-time integrator with that of a real integrator with focus an OTA parameters and noise analysis. Beside the noise sources at the non-inverting input of the OTA special care has to be taken to account for capacitances at the inverting input. The Noise Equivalent Temperature Difference (NETD) as the key parameter for bolometer applications for a real short-time integrator will be derived. As the result it will be shown, that the NETD is 1/f-noise limited.

scholarly journals Noise conversion of Schottky diodes in mm-wave detectors under different nonlinear regimes: modeling and simulation versus measurement

2015 ◽  
Vol 8 (3) ◽  
pp. 479-493 ◽  
Author(s):  
Jéssica Gutiérrez ◽  
Kaoutar Zeljami ◽  
Enrique Villa ◽  
Beatriz Aja ◽  
Maria Luisa de la Fuente ◽  
...  
Keyword(s):  
Transfer Functions ◽  
Noise Analysis ◽  
Schottky Diodes ◽  
Source Parameters ◽  
Low Frequency ◽  
Operating Conditions ◽  
Noise Sources ◽  
Wave Detector ◽  
Detector Output ◽  
Conversion Matrix

This paper presents and discusses several methods for predicting the low-frequency (LF) noise at the output of a mm-wave detector. These methods are based on the extraction of LF noise source parameters from the single diode under a specific set of bias conditions and the transfer or conversion of these noise sources, under different operating conditions including cyclostationary regime, to the quasi-dc output of a mm-wave detector constructed with the same model of diode. The noise analysis is based on a conversion-matrix type formulation, which relates the carrier noisy sidebands of the input signal with the detector output spectrum through a pair of transfer functions obtained in commercial software. Measurements of detectors in individual and differential setups will be presented and compared with predictions.

scholarly journals Noise Considerations of Integrators for Current Readout Circuits

2005 ◽  
Vol 3 ◽  
pp. 331-336 ◽  
Author(s):  
B. Bechen ◽  
A. Kemna ◽  
M. Gnade ◽  
T. v. d. Boom ◽  
B. Hosticka
Keyword(s):  
Dynamic Range ◽  
Noise Analysis ◽  
Readout Circuit ◽  
Noise Sources ◽  
Input Capacitance ◽  
Readout Circuits ◽  
Gain Switching ◽  
A Current

Abstract. In this paper the noise analysis of a current integrator is carried out and measures to reduce the overall noise are presented. The effects of various noise sources are investigated and their dependence on the input capacitance and on the gate area of the input transistors of the OTA used for the readout is shown. Both, input capacitance and gate area, should be kept as small as possible. Moreover, the linearity of the integrator is examined. In addition to that, the available application of such sensor readout circuit, which is a CMOS photodetector readout, is introduced. It uses an automatic gain switching, so that the dynamic range is extended.

Master curves for the response of layered systems to compressional seismic waves

1967 ◽  
Vol 57 (3) ◽  
pp. 515-543 ◽  
Author(s):  
Luis M. Fernandez
Keyword(s):  
Seismic Waves ◽  
Transfer Functions ◽  
Point Of View ◽  
Time Lags ◽  
Master Curves ◽  
Layer System ◽  
Crust And Upper Mantle ◽  
Response Characteristics ◽  
Families Of Curves ◽  
Short Time

abstract The layers of the earth's crust act as a filter with respect to seimic energy arriving at a given station. Consequently the motion recorded at the surface depends not only on the frequency content of the source and on the response characteristics of the recording instrument, but also on the elastic parameters and thicknesses of the transmitting layers. This latter dependence is the basis for a method of investigating the structure of the crust and upper mantle. To facilitate this investigation a set of master curves for the transfer functions of the vertical and horizontal component of longitudinal waves and their ratios is presented. The calculation of these curves is in terms of a dimensionless parameter. This calculation allows one to group the curves corresponding to different crustal models into families of curves. The characteristics of these curves are discussed from the point of view of their “periodicity” in the frequency domain and of their amplitude in order to investigate the influence of the layer parameters. Considerations, either of constructive interference or of Fourier analysis of a pulse multiply reflected within the layer system, reveal that the amplitudes of the transfer curves depend on the velocity contrasts at the interfaces of the system. The “periodicity” or spacing of the peaks depends on the time lags between the first arrivals and the arrivals of the different reverberations. Closely spaced fluctuations correspond to large-time lags, and widely spaced fluctuations to short-time lags.

Exposure to industrial noise: impacts on cognitive performance

2021 ◽  
Vol 263 (4) ◽  
pp. 2590-2600
Author(s):  
Luiz Henrique Mesa Casa Pereira ◽  
Björn Knöfel ◽  
Jan Troge ◽  
Welf-Guntram Drossel ◽  
Marcel Klein ◽  
...  
Keyword(s):  
Cognitive Performance ◽  
Noise Analysis ◽  
Low Frequency ◽  
Cumulative Effect ◽  
Noise Sources ◽  
Industrial Noise ◽  
Sound Levels ◽  
Office Environments ◽  
High Sound ◽  
High Frequency Content

Research on the relation between exposure to noise and cognitive performance inside industrial environments is not as broad as on office environments. For a better understanding of the specific industrial noise problems, participants performed arithmetic tests inside a hemi anechoic room while they were exposed to sounds of five typical industrial noise sources. The subjects also classified how annoying they perceived the noise signals. The effect of noise on the arithmetic test's performance was larger on accuracy than on velocity, which was verified using a Student t-test. Spectral-temporal characteristics - especially high frequency content and strong low frequency modulation - appear to relate better with lower performance on the test than high sound levels. Subjects that evaluated noise as more annoying performed worse in a final arithmetic test (under silence) after being exposed to the noises, indicating a possible cumulative effect of noise on performance. The findings provide a better insight in the cognitive behavior of people who are exposed to industrial noise. Hence, the study will proceed with the specific noise analysis of single industrial workplaces.

scholarly journals 7.5. Tentative detection of far infrared excess in Arp 220

1998 ◽  
Vol 184 ◽  
pp. 301-302
Author(s):  
Kin-Wing Chan ◽  
S. H. Moseley ◽  
E. Dwek ◽  
T. L. Roellig ◽  
S. Casey ◽  
...  
Keyword(s):  
Synchrotron Radiation ◽  
Time Scale ◽  
Far Infrared ◽  
Infrared Emission ◽  
Short Time Scale ◽  
Active Nucleus ◽  
Infrared Excess ◽  
Grating Spectrometer ◽  
The Galaxy ◽  
Short Time

We report 36 to 50 μm observations of Arp 220 by the Goddard Cryogenic Grating Spectrometer on the Kuiper Airborne Observatory in May 1994. In this measurement, we find the galaxy to be four times brighter than in the measurements of Joy et al. (1986). If both of the observations are correct, this large far infrared luminosity increasing in a short time scale between the two observations suggests that the infrared emission in Arp 220 consists mostly of nonthermal synchrotron radiation which originates from the active nucleus.

Pseudo-linear-array analysis of passive surface waves based on beamforming

2020 ◽  
Vol 221 (1) ◽  
pp. 640-650
Author(s):  
Ya Liu ◽  
Jianghai Xia ◽  
Feng Cheng ◽  
Chaoqiang Xi ◽  
Chao Shen ◽  
...  
Keyword(s):  
Surface Wave ◽  
Surface Waves ◽  
Urban Areas ◽  
High Efficiency ◽  
Linear Array ◽  
Array Analysis ◽  
Noise Sources ◽  
Set Up ◽  
Wave Methods ◽  
Short Time

SUMMARY Linear arrays are usually deployed for passive surface-wave investigations because of their high efficiency and convenience. In populated urban areas, it is almost impossible to set up a 2-D array in terms of the restriction from the existing infrastructures. The limited azimuthal coverage, however, lacks the ability to attenuate velocity overestimation caused by directional noise sources. We came up with a novel idea to compensate the azimuthal coverage by adding two more offline receivers to a conventional linear array, which is called pseudo-linear-array analysis of passive surface waves (PLAS). We used a beamforming algorithm to capture noise sources distribution and extract accurate dispersion curves. We used array response function to explain the superiority of the pseudo-linear array over the linear array and present the basic workflow of PLAS. Synthetic tests and field examples demonstrated the feasibility of PLAS to measure unbiased dispersion image. Comparison with mostly used passive surface wave methods (refraction microtremor, multichannel analysis of passive surface waves, spatial autocorrelation method, frequency–wavenumber analysis) suggested that PLAS can serve as an alternative passive surface wave method, especially in urban areas with restricted land accessibility and short-time acquisition demands.

Experimental Studies of Excess Noise Sources in Concrete Based Materials as a Limiting Factor for Electromagnetic Emission Measurement

2013 ◽  
Vol 592-593 ◽  
pp. 529-532
Author(s):  
Robert Macků ◽  
Pavel Koktavý ◽  
Tomas Trčka ◽  
Vladimir Holcman
Keyword(s):  
Flicker Noise ◽  
Noise Analysis ◽  
Experimental Studies ◽  
Electromagnetic Emission ◽  
Dielectric Materials ◽  
Excess Noise ◽  
Limiting Factor ◽  
Emission Measurement ◽  
Noise Sources ◽  
Geometrical Properties

This paper deals with excess noise sources in dielectric materials. We focus especially on the concrete samples that are frequently tested to ensure information about the reliability and level of degradation. Nevertheless, the testing methods are limited mainly by the proper contact creation, signal detection and noise defined sensitivity. Our efforts are directed to the noise properties assessment. It turns out that the Johnson-Nyquist noise and the 1/f (flicker) noise are generated in the different regions with the different response to the internal or external electric field. In addition the noise analysis is affected by the internal polarization phenomena and the material residual humidity. This issue in connection with the sample geometrical properties and the dielectric noise measurement methodology take part in this paper.

Investigating Spatio-temporal Changes in Subglacial Hydrology from Dense Array Seismology.

2020 ◽  
Author(s):  
Ugo Nanni ◽  
Florent Gimbert ◽  
Philippe Roux ◽  
Albanne Lecointre
Keyword(s):  
Water Flow ◽  
Seismic Noise ◽  
Water Pressure ◽  
Noise Analysis ◽  
Drainage System ◽  
Dense Array ◽  
Noise Sources ◽  
Spatio Temporal ◽  
Surrounding Areas ◽  
Subglacial Drainage

<p>Subglacial hydrology strongly modulates glacier basal sliding, and thus likely exerts a major control on ice loss and sea-level rise. However, the limited direct and spatialized observations of the subglacial drainage system make difficult to assess the physical processes involved in its development. Recent work shows that detectable seismic noise is generated by subglacial water flow, such that seismic noise analysis may be used to retrieve the physical properties of subglacial channelized water flow. Yet, investigating the spatial organisation of the drainage system (e.g. channels numbers and positions) together with its evolving properties (e.g. pressure conditions) through seismic observations remains to be done. The objective of this study is to bring new insights on the subglacial hydrology spatio-temporal dynamics using dense array seismic observations.</p><p>We use 1-month long ground motion records at a hundred of sensors deployed on the Argentière Glacier (French Alps) during the onset of the melt season, when the subglacial drainage system is expected to strongly evolve in response to the rapidly increasing water input. We conduct a multi-method approach based on the analysis of both amplitude and phase maps of seismic signals. We observe characteristic spatial patterns, consistent across those independent approaches, which we attribute to the underlying subglacial drainage system.</p><p>The phase-driven approach shows seismic noise sources that focuses in the along-flow direction as the water input increases. We identify this evolution as the development of the main subglacial channel whose position is coherent with the one expected from hydraulic potential calculations. During periods of rapid changes in water input (5 days over 31) and concomitant glacier acceleration the amplitude-driven approach shows spatial pattern highly consistent with the seismic noise sources location. At this time, we suggest that the spatial variations in the amplitude are representative of the water pressure conditions in subglacial channels and surrounding areas. Our spatialized observations therefore reveal the spatio-temporal evolution of the subglacial drainage system together with its changing pressure conditions. We observe, for instance, that channels develop at the very onset of the melt-season and rapidly capture the water from surrounding areas. Such unique observations may allow to better constrain the physics of subglacial water flow and therefore strengthen our knowledge on the dynamics of subglacial environments.</p>

Low Frequency Noise Analysis in Advanced CMOS Devices

2011 ◽  
Vol 324 ◽  
pp. 441-444 ◽  
Author(s):  
Jalal Jomaah ◽  
Majida Fadlallah ◽  
Gerard Ghibaudo
Keyword(s):  
Experimental Data ◽  
Noise Analysis ◽  
Low Frequency ◽  
Deep Submicron ◽  
Electrical Noise ◽  
Frequency Noise ◽  
Low Frequency Noise ◽  
Noise Sources ◽  
The Impact ◽  
Mobility Fluctuations

A review of recent results concerning the low frequency noise in modern CMOS devices is given. The approaches such as the carrier number and the Hooge mobility fluctuations used for the analysis of the noise sources are illustrated through experimental data obtained on advanced CMOS generations. Furthermore, the impact on the electrical noise of the shrinking of CMOS devices in the deep submicron range is also shown.

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