scholarly journals Design of a Carrier Wave for Capacitive Transducer with Large Dynamic Range

Sensors ◽  
2020 ◽  
Vol 20 (4) ◽  
pp. 992 ◽  
Author(s):  
Zhu Li ◽  
Xian Zhang ◽  
Shu Zou ◽  
Xiangqing Huang ◽  
Chao Xue ◽  
...  
Keyword(s):  
Dynamic Range ◽  
Noise Analysis ◽  
New Method ◽  
Capacitive Transducer ◽  
Limiting Factor ◽  
Voltage Reference ◽  
Direct Digital Synthesis ◽  
Carrier Wave ◽  
Amplitude Noise ◽  
Lower Amplitude

Capacitive transducers are widely used in fundamental physics experiments, seismology, Earth or planetary observations, and space scientific and technical applications because of their high precision, simple structure, and compatibility with various measurements. However, in real applications, there is a trade-off between their resolution and dynamic range. Therefore, this paper is aimed at enlarging the dynamic range while ensuring high resolution. In this paper, a noise analysis of a capacitive transducer is presented, which shows that the amplitude noise of the carrier wave is the main limiting factor. Hence, a new method of generating a carrier wave with lower-amplitude noise is proposed in the paper. Based on the experimental verification, it is found that the carrier wave produced through the new method performed significantly better than the typical digital carrier wave when they were compared in the same sensing circuit. With the carrier wave produced through the new method, the dynamic range of the capacitive transducer can reach 120.7 dB, which is 18.3 dB greater than for the typical direct digital synthesis (DDS) method. In addition, the resolution of the carrier wave is mainly limited by the voltage reference components.

An Improved Doppler Shift Simulation Method Based on Third-Order DDS

2014 ◽  
Vol 614 ◽  
pp. 356-362 ◽  
Author(s):  
Rui Li ◽  
Yuan Long Cai ◽  
Xin Bei Bai ◽  
Ming Quan Lu
Keyword(s):  
Doppler Shift ◽  
Dynamic Range ◽  
Doppler Frequency ◽  
Simulation Method ◽  
Global Navigation Satellite Systems ◽  
Direct Digital Synthesis ◽  
Third Order ◽  
Satellite Systems ◽  
Digital Synthesis ◽  
Global Navigation Satellite

A method to simulate the Doppler frequency shift of high dynamic signals of Global Navigation Satellite Systems (GNSS) is provided in this paper. The methodology of the method based on third-order Direct Digital Synthesis (DDS) is introduced and the efficient implementation architecture is proposed. The design criteria of the DDS are investigated according to the precision and dynamic range of the Doppler shift. The simulation results are also demonstrated, which indicate that the method is available for the high precision Doppler shift simulation of GNSS signals.

scholarly journals On What Scale Can We Predict the Agronomic Onset of the West African Monsoon?

2016 ◽  
Vol 144 (4) ◽  
pp. 1571-1589 ◽  
Author(s):  
Rory G. J. Fitzpatrick ◽  
Caroline L. Bain ◽  
Peter Knippertz ◽  
John H. Marsham ◽  
Douglas J. Parker
Keyword(s):  
West Africa ◽  
Noise Analysis ◽  
West African Monsoon ◽  
West African ◽  
New Method ◽  
The West ◽  
African Monsoon ◽  
Spatial Consistency ◽  
Local Stakeholders ◽  
Local Rainfall

Abstract Accurate prediction of the commencement of local rainfall over West Africa can provide vital information for local stakeholders and regional planners. However, in comparison with analysis of the regional onset of the West African monsoon, the spatial variability of the local monsoon onset has not been extensively explored. One of the main reasons behind the lack of local onset forecast analysis is the spatial noisiness of local rainfall. A new method that evaluates the spatial scale at which local onsets are coherent across West Africa is presented. This new method can be thought of as analogous to a regional signal against local noise analysis of onset. This method highlights regions where local onsets exhibit a quantifiable degree of spatial consistency (denoted local onset regions or LORs). It is found that local onsets exhibit a useful amount of spatial agreement, with LORs apparent across the entire studied domain; this is in contrast to previously found results. Identifying local onset regions and understanding their variability can provide important insight into the spatial limit of monsoon predictability. While local onset regions can be found over West Africa, their size is much smaller than the scale found for seasonal rainfall homogeneity. A potential use of local onset regions is presented that shows the link between the annual intertropical front progression and local agronomic onset.

scholarly journals Development of a new method for ATFCM based on trajectory-based operations

2017 ◽  
Vol 233 (1) ◽  
pp. 261-284 ◽  
Author(s):  
Dany Gatsinzi ◽  
Francisco J Saez Nieto ◽  
Irfan Madani
Keyword(s):  
Traffic Control ◽  
Hot Spot ◽  
Control Variable ◽  
Air Traffic ◽  
New Method ◽  
Limiting Factor ◽  
Time Of Arrival ◽  
Closure Rate ◽  
Control Intervention ◽  
The Times

This paper discusses a possibility to evolve the current Air Traffic Flow and Capacity Management towards a more proactive approach. This new method focuses on reducing the expected probability of air traffic control intervention based on “hot spot” identification and mitigation at strategic level by applying subliminal changes on the times of arrival at the crossing or merging points (junctions). The concept is fully aligned with the trajectory-based operation principles. The approach assumes that the changes on the times of arrival only demand small speed changes from the involved aircraft. In this study, the hot spots are defined as clusters of aircraft expected to arrive to the junctions. Two aircraft are said to be in the same cluster if their proximity and closure rate are below a given threshold. Some exercises are proposed and solved by applying this method. The obtained results show its ability to remove the potential conflicts by applying simple linear programming. This approach seeks to change the current capacity limiting factor, established by the number of aircraft occupying simultaneously each sector, to another parameter where the level of traffic complexity, flowing towards junctions, is identified and mitigated at strategic level. The speed changes, used as the control variable and computed before or during the flight, are designed to provide an adjustment on aircraft’s required time of arrival at the junctions in order to have a de-randomised and well-behaved (conflict free) traffic. This will enable improvements in airspace capacity/ safety binomial. It is recognised that this measure alone is unable to produce a conflict free airspace, and then other collaborative and coordinated actions, such as adjusting and swapping departing times at the departing airports (before the aircraft are taking off), offsetting some flights from nominal route, and allowing multi-agent separation management (while they are in flight) should be applied together with this method.

scholarly journals Design and Validation of Probes and Sensors for the Characterization of Magneto-Ionic Radio Wave Propagation on Near Vertical Incidence Skywave Paths

Sensors ◽  
2019 ◽  
Vol 19 (11) ◽  
pp. 2616
Author(s):  
Ben A. Witvliet ◽  
Rosa M. Alsina-Pagès ◽  
Erik van Maanen ◽  
Geert Jan Laanstra
Keyword(s):  
Magnetic Field ◽  
Wave Propagation ◽  
Radio Wave ◽  
Dynamic Range ◽  
Signal To Noise Ratio ◽  
Radio Wave Propagation ◽  
Direct Digital Synthesis ◽  
Earth’S Magnetic Field ◽  
Earth's Magnetic Field ◽  
Propagation Of Waves

This article describes the design and validation of deployable low-power probes and sensors to investigate the influence of the ionosphere and the Earth’s magnetic field on radio wave propagation below the plasma frequency of the ionosphere, known as Near Vertical Incidence Skywave (NVIS) propagation. The propagation of waves that are bent downward by the ionosphere is dominated by a bi-refractive mechanism called ‘magneto-ionic propagation’. The polarization of both downward waves depends on the spatial angle between the Earth’s magnetic field and the direction of propagation of the radio wave. The probes and sensors described in this article are needed to simultaneously investigate signal fading and polarization dynamics on six radio wave propagation paths. The 1-Watt probes realize a 57 dB signal-to-noise ratio. The probe polarization is controlled using direct digital synthesis and the cross-polarization is 25–35 dB. The intermodulation-free dynamic range of the sensor exceeds 100 dB. Measurement speed is 3000 samples/second. This publication covers design, practical realization and deployment issues. Research performed with these devices will be shared in subsequent publications.

scholarly journals Equivalence of Open-Loop and Closed-Loop Operation of SAW Resonators and Delay Lines

Sensors ◽  
2019 ◽  
Vol 19 (1) ◽  
pp. 185 ◽  
Author(s):  
Phillip Durdaut ◽  
Michael Höft ◽  
Jean-Michel Friedt ◽  
Enrico Rubiola
Keyword(s):  
Closed Loop ◽  
Dynamic Range ◽  
Limit Of Detection ◽  
Noise Analysis ◽  
Open Loop ◽  
Sensor System ◽  
Electronic Systems ◽  
Delay Lines ◽  
Resonant Sensors ◽  
Closed Loop Systems

Surface acoustic wave (SAW) sensors in the form of two-port resonators or delay lines are widely used in various fields of application. The readout of such sensors is achieved by electronic systems operating either in an open-loop or in a closed-loop configuration. The mode of operation of the sensor system is usually chosen based on requirements like, e.g., bandwidth, dynamic range, linearity, costs, and immunity against environmental influences. Because the limit of detection (LOD) at the output of a sensor system is often one of the most important figures of merit, both readout structures, i.e., open-loop and closed-loop systems, are analyzed in terms of the minimum achievable LOD. Based on a comprehensive phase noise analysis of these structures for both resonant sensors and delay line sensors, expressions for the various limits of detection are derived. Under generally valid conditions, the equivalence of open-loop and closed-loop operation is shown for both types of sensors. These results are not only valid for SAW devices, but are also applicable to all kinds of phase-sensitive sensors.

scholarly journals Development of a shutterless continuous rotation method using an X-ray CMOS detector for protein crystallography

2009 ◽  
Vol 42 (6) ◽  
pp. 1165-1175 ◽  
Author(s):  
Kazuya Hasegawa ◽  
Kunio Hirata ◽  
Tetsuya Shimizu ◽  
Nobutaka Shimizu ◽  
Takaaki Hikima ◽  
...  
Keyword(s):  
Data Collection ◽  
Dynamic Range ◽  
Protein Structures ◽  
Protein Crystallography ◽  
New Method ◽  
Oxide Semiconductor ◽  
X Ray ◽  
Rotation Method ◽  
Continuous Rotation ◽  
Wide Range

A new shutterless continuous rotation method using an X-ray complementary metal-oxide semiconductor (CMOS) detector has been developed for high-speed, precise data collection in protein crystallography. The principle of operation and the basic performance of the X-ray CMOS detector (Hamamatsu Photonics KK C10158DK) have been shown to be appropriate to the shutterless continuous rotation method. The data quality of the continuous rotation method is comparable to that of the conventional oscillation method using a CCD detector and, furthermore, the combination with fine φ slicing improves the data accuracy without increasing the data-collection time. The new method is more sensitive to diffraction intensity because of the narrow dynamic range of the CMOS detector. However, the strong diffraction spots were found to be precisely measured by recording them on successive multiple images by selecting an adequate rotation step. The new method has been used to successfully determine three protein structures by multi- and single-wavelength anomalous diffraction phasing and has thereby been proved applicable in protein crystallography. The apparatus and method may become a powerful tool at synchrotron protein crystallography beamlines with important potential across a wide range of X-ray wavelengths.

Optical profilometer: a new method for high sensitivity and wide dynamic range

1982 ◽  
Vol 21 (17) ◽  
pp. 3200 ◽  
Author(s):  
Yeshaiahu Fainman ◽  
Ehud Lenz ◽  
Joseph Shamir
Keyword(s):  
Dynamic Range ◽  
High Sensitivity ◽  
New Method ◽  
Wide Dynamic Range ◽  
Optical Profilometer

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.

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