Effective Dynamic Range Research Articles

A sensitive and high dynamic range laser energy meter

We report a sensitive and high dynamic range photodiode-based laser energy meter. The essential blocks of the energy meter are the photodetector circuit, the signal conditioning circuit and the capacitor discharge circuit. The output signal of the energy meter is read on an oscilloscope. The effective dynamic range of the energy meter measured at a laser wavelength of 532 nm is 6 × 106 and the minimum detectable energy is about 2 pJ. The large dynamic range is obtained by incorporating different energy sensing capacitors and the amplification of the input signal. The minimum detectable energy and the effective dynamic range of the energy meter are better than that of the energy meters reported in the literature.

Producing Highly Charged Ions without Solvent Using Laserspray Ionization: A Total Solvent-Free Analysis Approach at Atmospheric Pressure

First examples of highly charged ions in mass spectrometry (MS) produced from the solid state without using solvent during either sample preparation or mass measurement are reported. Matrix material, matrix/analyte homogenization time and frequency, atmospheric pressure (AP) to vacuum inlet temperature, and mass analyzer ion trap conditions are factors that influence the abundance of the highly charged ions created by laserspray ionization (LSI). LSI, like matrix-assisted laser desorption/ionization (MALDI), uses laser ablation of a matrix/analyte mixture from a surface to produce ions. Preparing the matrix/analyte sample without the use of solvent provides the ability to perform total solvent-free analysis (TSA) consisting of solvent-free ionization and solvent-free gas-phase separation using ion mobility spectrometry (IMS) MS. Peptides and small proteins such as non-β-amyloid components of Alzheimer's disease and bovine insulin are examples in which LSI and TSA were combined to produce multiply charged ions, similar to electrospray ionization, but without the use of solvent. Advantages using solvent-free LSI and IMS-MS include simplicity, rapid data acquisition, reduction of sample complexity, and the potential for an enhanced effective dynamic range. This is achieved by more inclusive ionization and improved separation of mixture components as a result of multiple charging.

마이크로 홀로그래픽 시스템에서 미디어의 소진효과

Abstract In microholographic data storage system (MDSS), compact recording is required to achieve high capacity.[1] When the data is recorded, neighbor monomer is also affected by reaction at the focal point.[2,3] This unintended process caused more monomer consumption and degradation of total capacity. To avoid this extra consumption of dynamic range, it is required to define the effective dynamic range for MDSS. In this paper, we experimentally investigate the relation between dynamic range consumption and micro grating formation. Dynamic range consumption was monitored by real time read-out system. Micrograting was recorded with different consumption ratio and compared by diffraction efficiency of track direction. Finally, we define suitable dynamic range for MDSS Key Words : Microhologram,, Photopolymer, Dynamic range 1. 서서 론론론       ! # $% . & ' (!&)* + ,-. /012 34 +5 ,-. 6 7.  89 :; ? +5 ,-. /01 !@ !  A  $6 BC% . (!&)* + ,-. /012 3D EF GF9 HI 3D J< = $%6 KL , MN , Shift, OPQR %'S T %'S 3UV WX , 34 +5 ,-. YZ [T HI  V \W6 ] ^W% . _ (!&)* + ,-. /012 9 `

A miniature mass analyser for in-situ elemental analysis of planetary material–performance studies

The performance of a laser ablation mass analyser designed for in-situ exploration of the chemical composition of planetary surfaces has been investigated. The instrument measures the elemental and isotopic composition of raw solid materials with high spatial resolution. The initial studies were performed on NIST standard materials using IR laser irradiance (< 1 GW cm(-2)) at which a high temporal stability of ion formation and sufficiently low sample consumption was achieved. Measurements of highly averaged spectra could be performed with typical mass resolution of m/Δm ≈ 600 in an effective dynamic range spanning seven decades. Sensitive detection of several trace elements can be achieved at the ~ ppm level and lower. The isotopic composition is usually reproduced with 1% accuracy, implying good performance of the instrument for quantitative analysis of the isotopic fractionation effects caused by natural processes. Using the IR laser, significant elemental fractionation effects were observed for light elements and elements with a high ionization potential. Several diatomic clusters of major and minor elements could also be measured, and sometimes these interfere with the detection of trace elements at the same nominal mass. The potential of the mass analyser for application to sensitive detection of elements and their isotopes in realistic samples is exemplified by measurements of minerals. The high resolution and large dynamic range of the spectra makes detection limits of ~100 ppb possible.

Irreversible sensing of oxygen ingress

Absorption-based opto-chemical sensors for oxygen are presented that consist of leuco dyes (leuco indigo and leuco thioindigo) incorporated into two kinds of polymer matrices. An irreversible and visible color change (to red or blue) is caused by a chromogenic chemistry involving the oxidation of the (virtually colorless) leuco dyes by molecular oxygen. The moderately gas permeable copolymer poly(styrene- co-acrylonitrile) and a highly oxygen-permeable polyurethane hydrogel, respectively, are used in order to increase the effective dynamic range for visualizing and detecting oxygen. We describe the preparation and properties of four different types of such oxygen sensors that are obtained by dip-coating a gas impermeable foil made from poly(ethylene terephthalate) with a sensor layer composed of leuco dye and polymer.

Analytical procedures for the determination of polychlorinated- p-dioxins, polychlorinated dibenzofurans, and hexachlorobenzene in pentachlorophenol

A method for the determination of all polychlorinated dibenzo- p-dioxin (PCDDs) and polychlorinated dibenzofurans (PCDFs), and hexachlorobenzene (HCB) contained in production batches of pentachlorophenol (PCP) samples is presented. The method uses two sub-samples of the PCP sample to provide an effective dynamic range of 1:40,000,000. Following extraction of the samples and fractionation of the sample extracts, the extracts are analyzed by HRGC/HRMS, and the resulting data from both sub-samples are combined to generate the final data for each sample. Data from the analysis of 47 samples using this method are presented and show a ratio of concentrations of octachlorinated dibenzofuran (OCDF) to 2,3,7,8-tetrachlorinated dibenzofuran (TCDF) of approximately 4,000,000:1. The results show that four congeners dominate the ITEQ, which has an average value of 634 μg kg −1 (429 μg kg −1 WHO 2005 TEQ) in those samples.

The Effective Dynamic Ranges of Standard Automated Perimetry Sizes III and V and Motion and Matrix Perimetry

To establish the associations between threshold estimates of 4 perimetric tests and to define and compare the tests' effective dynamic ranges. We examined 152 patients with glaucoma and 80 controls using standard automated perimetry (SAP) with stimulus size III, SAP with size V, and motion and matrix perimetry. We explored the intertest associations using principal-components analysis. We defined the effective dynamic range bottom using the frequency of 0-dB trials on retest. We defined the upper effective dynamic range as a value above which fewer than 0.5% of the values fall in the controls. We also calculated the number of discriminable steps from normal to the floor value of the perimeter. The association between SAP III and V was approximately linear up to a sensitivity of about 20 dB on both tests and with motion and matrix perimetry up to about 25 dB from 0 dB. While the upper bounds were similar among the tests, size V SAP had a lower floor and more discriminable steps. The effective dynamic range of SAP III is substantially less than its physically tested limits. Size V stimuli have a greater effective dynamic range than size III by about 1 log unit and have about twice as many discriminable steps.

Grid-scroll hyperchaotic system based on microcontroller digital hardware implementation

Based on the microcontroller (MCU), a universal digital hardware experimental circuit for four-dimensional chaotic system is designed, from which 9×7-grids scroll chaotic and hyperchaotic attractors are generated. Reference [1] has presented a four-dimensional multi-scroll hyperchaotic system extended from Colpitts oscillator model. In this paper, a new four-dimensional grid-scroll hyperchaotic system is constructed by introducing a unit sawtooth wave function to replace the triangular function in the original system, which is realized by utilizing MCU digital hardware implementation easily. Analysis and numerical simulations are performed for the formation mechanism of grid-scroll attractor in the new system. By using Euler algorithm to discretize the proposed grid-scroll hyperchaotic system, an attractor with more grid-scroll number than that of the original system can be generated in the effective dynamic range of the experimental circuit. Experimental results verified the feasibility of grid-scroll hyperchaotic system based on MCU implementation.

Front-end electronics for the ALICE calorimeters

The ALICE calorimeters PHOS and EMCal are based on Avalanche Photo-Diode (APD) photosensors with Charge Sensitive Preamplifiers (CSP) for readout of the scintillating elements. The amplified signals are read out via 32-channel shaper/digitizer front-end electronics (FEE) with 14-bit effective dynamic range. The electronics is based on second order shapers with dual gain for each channel, getting digitized by ALTRO chips. Each APD channel is equipped with an individual 10-bit APD gain adjustment and 2 × 2 channel clusters generate a 100 ns shaped analog sums output (Fast OR) for the associated Trigger Region Units (TRU). The Fast OR signals are generated by first order shapers with a dynamic range of 12-bit given by the ADC in the TRU cards. Board controller firmware in the FPGA provides local monitoring and configuration of all parameters via the ALICE DCS system. The signal to noise ratio for MIP at 215 MeV is ∼ 7 per channel with a noise level of 30 MeV at room temperature for a dynamic range of 80 GeV for PHOS, and the fast-OR RMS noise level is about 75 MeV for a dynamic range of 250 GeV for EMCal.

Signal specific electric potential sensors for operation in noisy environments

Limitations on the performance of electric potential sensors are due to saturation caused by environmental electromagnetic noise. The work described involves tailoring the response of the sensors to reject the main components of the noise, thereby enhancing both the effective dynamic range and signal to noise. We show that by using real-time analogue signal processing it is possible to detect a human heartbeat at a distance of 40 cm from the front of a subject in an unshielded laboratory. This result has significant implications both for security sensing and biometric measurements in addition to the more obvious safety related applications.

A Novel Fiber Bragg Grating Sensor Configuration for Long-Distance Quasi-Distributed Measurement

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> A novel fiber Bragg grating (FBG) sensor configuration using three broadband light sources of different wavelength bands for the interrogation of FBG sensors distributed over 75 km of fiber is proposed and demonstrated. Rayleigh backscattering was reduced and a 60-dB effective dynamic range was demonstrated. </para>

Clinical ultraviolet dosimetry with a CCD monochromator array spectroradiometer

Single monochromator charge-coupled device (CCD) array spectroradiometers have the advantage of ease of use and speed compared with double grating instruments. Their inherently inferior stray-light rejection, however, can critically affect their accuracy in phototherapy and research-related dosimetry applications. This paper shows that without adequate correction the HR4000 (Ocean Optics Inc., Dunedin, USA) array device can overestimate the CIE erythema-weighted irradiance of common phototherapy sources and solar simulator beams by over 100%. A software stray-light correction (Ylianttila et al 2005 Photochem. Photobiol. 81 333–41), using the measured slit function of the HR4000, has been applied to spectra acquired from sources used in phototherapy and photobiology (PUVA, UV21, TL01 and solar simulator). The resulting corrected erythema-weighted irradiance measurements from the HR4000 are within 10% of those from a DM150 double grating spectroradiometer (Bentham Instruments Ltd, Reading, UK). A simple model is considered for combining estimates of measurement uncertainties. The importance of exposure bracketing to improve the dynamic range of the HR4000 is illustrated, along with the difficulty in making direct comparison of spectral values between two instruments due to wavelength scale uncertainties. Comparison with a double grating instrument in a solar simulator beam is examined here as a basis for validating CCD array device measurements. The study demonstrates that the HR4000 array spectroradiometer can provide an adequate level of accuracy for common phototherapy and photobiology applications only where a suitable stray-light correction is carefully applied and where the instrument's effective dynamic range is improved.

Use of GafChromic film to diagnose laser generated proton beams

A calibration of three types of GafChromic radiochromic film (HS, MD-55, and HD-810) was carried out on the Crocker Nuclear Laboratory's 76 in. cyclotron at UC Davis over doses ranging from 0.001 to 15 kGy. The film was digitized with a scanning microdensitometer with which it was scanned twice with two different filters to increase the film's effective dynamic range. We demonstrate how this calibrated film can be used to measure the spectrum and total energy of a laser generated proton beam. This technique was applied to an experiment on the 10 J, 100 fs Callisto laser at Lawrence Livermore National Laboratory. The resulting proton spectrum was compared to that obtained by simultaneous measurement of Ti nuclear activation; the two methods give the same proton beam slope temperature and agree in number of protons to within 27%.

A model with compression for estimating speech intelligibility in quiet and in noise

For speech reception thresholds (SRTs), measured in normally‐hearing listeners using various types of stationary noise, the Speech Intelligibility Index (SII, ANSI S3.5‐1997) model predicts a fairly constant speech proportion (of about 0.3) necessary for sentence intelligibility. For SRTs in quiet, the estimated speech proportions are often lower, and show a larger inter‐subject variability, than found for speech in noise near normal speech levels. This might be related to the fact that cochlear compression is larger at normal speech levels than near the threshold for speech in quiet. The SII model does not take this into account. The present model attempts to alleviate this problem by including cochlear compression. It is based on a loudness model for normally‐hearing and hearing‐impaired listeners [ANSI S3.4‐2007]. It estimates internal excitation levels of the speech, accounts for the compressed effective dynamic range of the internal speech signal, and calculates the proportion of speech above thresho...

Opportunistic eigenbeamforming: Exploiting multiuser diversity and channel correlations

Multiuser diversity is an inherent form of diversity present in any time-varying system with several users. An opportunistic scheduler has to be used in order to exploit this type of diversity. A scheme that increases the effective dynamic range of the channel by deploying multiple antennas at the transmitter is called opportunistic beamforming. Opportunistic beamforming increases the degree of multiuser diversity in several scenarios, including correlated channels. Nevertheless, multiuser diversity can also be combined with other transmit schemes that have proven to be effective in correlated channels, such as eigenbeamforming. Eigenbeamforming is a point-to-point link transmit technique that could easily be combined with an opportunistic scheduler to extract multiuser diversity. We refer to the joint use of eigenbeamforming with an opportunistic scheduler as opportunistic eigenbeamforming. In this work, we show that the available multiuser diversity with opportunistic eigenbeamforming is larger than the one achieved when opportunistic beamforming is employed using the proportional fair scheduler under different degrees of correlation in the channel. In the present work we have considered a single-cell scenario.

High Dynamic Range Imaging by Fusing Multiple Raw Images and Tone Reproduction

This paper presents an integrated color imaging system for taking images in extremely high dynamic range scenes. The system first fuses several differently exposed raw images to acquire more intensity information. The effective dynamic range of the image raw data can be extended to 256 times if five differently exposed images are fused. Then it runs edge detection iterations to extract the image details in different luminance levels. The proposed tone reproduction algorithm equalizes the histogram of the extracted fine edges which tends to assign larger dynamic range for highly populated regions. Finally, the local contrast enhancement is performed to further refine the image details. The experimental results show that the proposed high dynamic range imaging system has good performance on both tone and color reproduction.

Skin Viscoelasticity Displays Site- and Age-Dependent Angular Anisotropy

One of the dominant characteristics of skin aging is loss of elasticity. Although the changes in the mechanical properties of the skin over several decades of life are substantial, objective measurements have failed to capture their magnitude thus far. Moreover, the mechanical properties of the skin are not uniform in all directions, and there is a need to understand this angular anisotropy. In this work we present a methodology of documenting the angular anisotropy of skin elasticity with high sensitivity and dynamic range using the Reviscometer® RVM 600 (Courage & Khazaka Electronic GmbH, Cologne, Germany). The method is based on determining the directional dependence of the speed of an acoustic shear wave on the skin surface at intervals of 3°. Based on the angular distribution of the resonance running time, we define two parameters: the anisotropy and the angular dispersion width. We find that with increasing age the anisotropy increases, while the angular dispersion width decreases. The ratio of these values provides a sensitive parameter for the assessment of the directional behavior of the skin mechanical properties. This parameter provides a large effective dynamic range capable of demonstrating close to an order of magnitude differences in skin viscoelasticity from infants up to adults 75 years of age. Furthermore, we show that the direction of the angular anisotropy relates to the direction of the dermal cleavage lines as defined by Langer, indicating that the anisotropy of the mechanical properties of skin stems from structural parameters. Based on these results, we conclude that the proposed methodology is able to capture accurately the age-dependent changes of the mechanical properties of the skin and to demonstrate a structure-function relationship.

Use of S-Shaped Input-Output Functions for Noise Suppression in Cochlear Implants

The aim of this study is to assess the influence of the shape of the acoustic-to-electric mapping function on speech recognition in noise by cochlear implant listeners. A new acoustic-to-electric mapping function is proposed for cochlear implant users in noisy environments. The proposed s-shaped mapping function was expansive for low input levels up to a knee point level and compressive thereafter. The knee point of the mapping functions changed dynamically and was set proportional to the estimated noise floor level. The performance of the mapping function was evaluated on a sentence recognition task using IEEE sentences embedded in +5 to 10 dB SNR multitalker babble and in +5 dB SNR speech-shaped noise. Nine postlingually deafened cochlear implant users participated in the study. Results indicated that the same s-shaped mapping function did not yield significant improvements for all cochlear implant users. Significant benefits in speech intelligibility were observed, however, when the s-shaped mapping function was optimized to individual cochlear implant users. Significantly higher performance was achieved with the s-shaped mapping functions than the conventional log mapping function used by cochlear implant users in their daily strategy, in both multitalker (+5 and +10 dB SNR) and continuous speech-shaped (+5 dB SNR) conditions. These results clearly indicate that the shape of the nonlinear acoustic-to-electric mapping can have a significant effect on speech intelligibility in noise when it is optimized to individual cochlear implant users. The log functions currently used in most implant processors for mapping acoustic to electric amplitudes are not the best mapping functions to use in noisy environments. This is largely because compressive functions tend to amplify low-level segments of speech along with noise, thereby decreasing the spectral contrast and effective dynamic range. In contrast, the s-shaped mapping functions, which are partly compressive and partly expansive depending on the signal level, are more suitable for noisy environments and can produce significantly higher performance than the log-mapping functions.

Design of power-efficient pipelined truncated multipliers with various output precision

An energy-efficient multiplier is very desirable for multimedia and digital signal processing systems. In many of these systems, the effective dynamic range of input operands for multipliers is generally limited to a small range and the case with maximum range seldom occurs. In addition, the output products of multipliers are usually rounded or truncated to avoid growth in word size. Based on these features, a low-power signed pipelined truncated multiplier is proposed that can dynamically detect multiple combinations of input ranges and deactivate a large amount of the unnecessary transitions in non-effective ranges to reduce the power consumption. Moreover, the proposed multiplier can trade output precision against power consumption so as to further reduce power consumption. Experimental results show that the proposed multiplier consumes up to 90% less power than the conventional standard multiplier while still maintaining an acceptable output precision and quality.

Characterization of Electromechanical Transduction in Polyelectrolyte Gels for Mechanical Sensor Applications

AbstractWe report a new experimental method for the characterization of the electromechanical properties of polyelectrolyte gels (PG). PGs have been studied extensively, but with limited success, as mechanical actuators. However, they are also promising as potentially biocompatible mechanical sensors. In order to integrate them into actual devices, their electromechanical transduction properties need to be characterized in a reproducible manner.We have therefore developed a technique to measure the mechanically induced change in electrostatic potential in PGs. The polyelectrolyte gel is subjected to a well-defined pressure gradient by placing a thin, flat sample on a substrate with integrated concentric Platinum electrodes and indenting it with a spherical indenter. The potential values at the electrodes are measured using a MOSFET operational amplifier circuit with an input impedance of 1014 Ù and an effective dynamic range better than 16 bit. This method can be directly used to quantify electromechanical coupling in polyelectrolyte gels.