scholarly journals SCLC Degradation in 980 nm Pump Laser by Using Electrical Noise

ISRN Optics ◽  
2012 ◽  
Vol 2012 ◽  
pp. 1-4
Author(s):  
B. Orsal ◽  
I. Asaad
Keyword(s):  
Defect Density ◽  
Optical Power ◽  
Longitudinal Mode ◽  
Pump Laser ◽  
Electrical Noise ◽  
Noise Sources ◽  
Noise Spectral Density ◽  
Noise Current ◽  
Noise Measurements ◽  
Pump Lasers

The knowledge of the noise levels is important for pump laser diodes as it allows to study and to locate the noise sources and their origin. 980 nm fresh and aged pump lasers have been characterized by using electrical noise measurements. At 10 Hz, the spectra are dominated by () noise. Current noise spectral density (CNSD) is dominated by (). The trapping defect density near the n+n- and p+p- interfaces is related to pinching of the space-charge-limited current (SCLC) effect. An excess electrical noise due to longitudinal mode hopping is correlated with optical power fluctuations.

New Method to Determine the a-Si:H Pin Diode Series Resistance by Noise Measurements

1998 ◽  
Vol 507 ◽  
Author(s):  
F. Blecher ◽  
K. Seibel ◽  
M. Hillebrand ◽  
M. Böhm
Keyword(s):  
Series Resistance ◽  
Partial Information ◽  
Low Noise ◽  
Operating Conditions ◽  
New Method ◽  
Measuring System ◽  
Pin Diode ◽  
Noise Current ◽  
Current Voltage ◽  
Noise Measurements

ABSTRACTThe series resistance limits the linearity of photodiodes and decreases the efficiency of solar cells. It is usually determined from IV-measurements for moderate and high forward current density. This method, however, provides only partial information about Rs, since the series resistance depends on the operating point. An alternative method is based on noise measurements. System noise of the measuring system with a low-noise current-voltage converter has been investigated. A new method for extraction of photodiode series resistance from noise measurements is suggested. Noise measurements are carried out for a-Si:H pin diodes. The series resistance of an amorphous pin diode has been extracted for different operating conditions using the new measurement method.

scholarly journals Parametric Power Spectral Density Analysis of Noise from Instrumentation in MALDI TOF Mass Spectrometry

2007 ◽  
Vol 3 ◽  
pp. 117693510700300 ◽  
Author(s):  
Hyunjin Shin ◽  
Miray Mutlu ◽  
John M. Koomen ◽  
Mia K. Markey
Keyword(s):  
Mass Spectrometry ◽  
Signal Processing ◽  
Mass Spectra ◽  
Thermal Noise ◽  
Electrical Noise ◽  
Noise Sources ◽  
Stochastic Signal ◽  
Power Spectral ◽  
Stochastic Signal Processing ◽  
Periodic Components

Noise in mass spectrometry can interfere with identification of the biochemical substances in the sample. For example, the electric motors and circuits inside the mass spectrometer or in nearby equipment generate random noise that may distort the true shape of mass spectra. This paper presents a stochastic signal processing approach to analyzing noise from electrical noise sources (i.e., noise from instrumentation) in MALDI TOF mass spectrometry. Noise from instrumentation was hypothesized to be a mixture of thermal noise, 1/f noise, and electric or magnetic interference in the instrument. Parametric power spectral density estimation was conducted to derive the power distribution of noise from instrumentation with respect to frequencies. As expected, the experimental results show that noise from instrumentation contains 1/f noise and prominent periodic components in addition to thermal noise. These periodic components imply that the mass spectrometers used in this study may not be completely shielded from the internal or external electrical noise sources. However, according to a simulation study of human plasma mass spectra, noise from instrumentation does not seem to affect mass spectra significantly. In conclusion, analysis of noise from instrumentation using stochastic signal processing here provides an intuitive perspective on how to quantify noise in mass spectrometry through spectral modeling.

Airframe noise measurements on JAXA Jet Flying Test Bed “Hisho” using a phased microphone array

2017 ◽  
Vol 16 (4-5) ◽  
pp. 255-273 ◽  
Author(s):  
Takehisa Takaishi ◽  
Hiroki Ura ◽  
Kenichiro Nagai ◽  
Yuzuru Yokokawa ◽  
Mitsuhiro Murayama ◽  
...  
Keyword(s):  
Microphone Array ◽  
Low Frequency ◽  
Landing Gear ◽  
Frequency Resolution ◽  
Test Bed ◽  
Noise Sources ◽  
Low Frequencies ◽  
Airframe Noise ◽  
Noise Measurements ◽  
Wooden Platform

In 2015, the Japan Aerospace Exploration Agency launched the Flight demonstration of QUiet technology to Reduce nOise from High-lift configurations project to verify by flight demonstration the feasibility of practical noise-reducing aircraft modification concepts. In order to serve as a baseline for comparison before modification, airframe noise sources of the JAXA Jet Flying Test Bed “Hisho” were measured with a 30 m diameter array of 195 microphones mounted on a wooden platform built temporary beside the runway of Noto Satoyama Airport in Japan. A classical Delay and Sum in the time domain beamforming algorithm was adapted for the present study, with weight factors introduced to improve the low-frequency resolution and autocorrelations eliminated to suppress wind noise at high frequencies. In the landing configuration at idle thrust, the main landing gear, nose landing gear, and side edges of the six extended flap panels were found to be the dominant “Hisho” airframe noise sources. Deconvolution by the DAMAS and CLEAN-SC algorithms provided clearer positions of these sound sources at low frequencies. Integration of acoustical maps agreed well with the sound pressure level measured by a microphone placed at the center of the microphone array and gave detailed information about the contribution of each noise source.

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.

Internally Generated Noise From Gas Turbine Engines. Measurement and Prediction

1967 ◽  
Vol 89 (2) ◽  
pp. 177-185 ◽  
Author(s):  
M. J. T. Smith ◽  
M. E. House
Keyword(s):  
Gas Turbine ◽  
Full Scale ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Test Results ◽  
Radiation Patterns ◽  
Noise Sources ◽  
Prediction Technique ◽  
Noise Measurements ◽  
Engine Compressor

The noise sources from gas turbine engines are defined and their radiation patterns identified from test results. Examination of single-stage and full-scale engine compressor noise measurements leads to a prediction technique being evolved for inlet and efflux levels.

Noise at Workplaces in the Call Center

2010 ◽  
Vol 35 (2) ◽  
pp. 253-264 ◽  
Author(s):  
Bożena Smagowska
Keyword(s):  
Hearing Loss ◽  
Call Center ◽  
Call Centers ◽  
European Countries ◽  
Assessment Criteria ◽  
Noise Sources ◽  
Work Activities ◽  
Basic Work ◽  
Noise Measurements

AbstractIn the last years the number of new forms of workplaces, such as call centers, increases. It is defined as a workstation where the basic tasks of a worker are carried out with the use of a phone and a computer. According to statistics, about 1.3-4% of workers are employed in call centers in the European countries. The noise is one of the harmful and annoying hazards of call center workstations. The paper presents the noise sources in call center rooms, assessment criteria of noise and results of noise measurements in call center workstations. The results of measurements show that the noise at call center workstations (during the use of handset receiver phone by operators) can be harmful (causing the risk of hearing loss) and annoying, as it makes it difficult to carry out the basic work activities and causes additionally auditory disadvantageous changes in health.

In situ characterization of laser diodes from wide-band electrical noise measurements

1986 ◽  
Vol 4 (7) ◽  
pp. 804-812 ◽  
Author(s):  
P. Andrekson ◽  
P. Andersson ◽  
A. Alping ◽  
S. Eng
Keyword(s):  
Laser Diodes ◽  
Wide Band ◽  
Electrical Noise ◽  
In Situ Characterization ◽  
Noise Measurements
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