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1

Error Analysis of the Recovery of Data Acquired by a Voltage-to-Frequency Data Acquisition System for Sinusoidal, Step, and Ramp Inputs.  

National Technical Information Service (NTIS)

The errors generated by the recovery of data acquired by a voltage-to-frequency (V/F) data acquisition system are theoretically analyzed, using a digital computer. The input waveforms considered are the sinusoid, the step function, and the ramp function. ...

G. L. Williams

1968-01-01

2

Experimental investigation of dielectric barrier discharge plasma actuators driven by repetitive high-voltage nanosecond pulses with dc or low frequency sinusoidal bias  

NASA Astrophysics Data System (ADS)

Experimental studies were conducted of a flow induced in an initially quiescent room air by a single asymmetric dielectric barrier discharge driven by voltage waveforms consisting of repetitive nanosecond high-voltage pulses superimposed on dc or alternating sinusoidal or square-wave bias voltage. To characterize the pulses and to optimize their matching to the plasma, a numerical code for short pulse calculations with an arbitrary impedance load was developed. A new approach for nonintrusive diagnostics of plasma actuator induced flows in quiescent gas was proposed, consisting of three elements coupled together: the schlieren technique, burst mode of plasma actuator operation, and two-dimensional numerical fluid modeling. The force and heating rate calculated by a plasma model was used as an input to two-dimensional viscous flow solver to predict the time-dependent dielectric barrier discharge induced flow field. This approach allowed us to restore the entire two-dimensional unsteady plasma induced flow pattern as well as characteristics of the plasma induced force. Both the experiments and computations showed the same vortex flow structures induced by the actuator. Parametric studies of the vortices at different bias voltages, pulse polarities, peak pulse voltages, and pulse repetition rates were conducted experimentally. The significance of charge buildup on the dielectric surface was demonstrated. The charge buildup decreases the effective electric field in the plasma and reduces the plasma actuator performance. The accumulated surface charge can be removed by switching the bias polarity, which leads to a newly proposed voltage waveform consisting of high-voltage nanosecond repetitive pulses superimposed on a high-voltage low frequency sinusoidal voltage. Advantages of the new voltage waveform were demonstrated experimentally.

Opaits, Dmitry F.; Likhanskii, Alexandre V.; Neretti, Gabriele; Zaidi, Sohail; Shneider, Mikhail N.; Miles, Richard B.; Macheret, Sergey O.

2008-08-01

3

Variable frequency sinusoidal oscillators based on CCII+  

Microsoft Academic Search

Using the two-integrator loop biquadratic general structure and positive second-generation current conveyor (CCII+) as the active elements, a set of variable frequency sinusoidal oscillators is synthesized. Some of the derived structures are new and three of them have been carefully analyzed because of their special interest at high frequency. Experimental results show an excellent agreement with theoretical predictions. Finally, it

P. A. Martinez; J. Sabadell; C. Aldea; S. Celma

1999-01-01

4

LLC series resonant high-frequency sinusoidal power supplier  

Microsoft Academic Search

This paper presents an LLC series resonant high-frequency sinusoidal power supplier for contactless power transmission system utilizing the magnetizing inductance and the leakage inductance of contactless coupled transformer. The design of system's parameters is under 2mm air gap of contactless coupled transformer and utilizes microchip dsPIC30F4011 to track resonance tank voltage and current phase in order to maintain operation of

Liang-Rui Chen; Chung-Ming Young; Hai-Wen Chang; Wen-Ren Yang; Neng-Yi Chu

2010-01-01

5

Frequency / Duty Cycle Control of LCC Resonant Converter Supplying High Voltage Very Low Frequency Test Systems  

E-print Network

Frequency / Duty Cycle Control of LCC Resonant Converter Supplying High Voltage Very Low Frequency», «Resonant converter», «Soft switching» Abstract Very low frequency (VLF) high-voltage (HV) sinusoidal test waves. Due to the wide ranges of output voltage and output load, both the switching frequency

Paderborn, Universität

6

Enhanced sheath heating in capacitively coupled discharges due to non-sinusoidal voltage waveforms  

SciTech Connect

Through the use of particle-in-cell simulations, we demonstrate that the power deposition in capacitively coupled discharges (in argon) can be increased by replacing sinusoidal waveforms with Gaussian-shaped voltage pulses (with a repetition frequency of 13.56 MHz). By changing the Gaussian pulse width, electron heating can be directly controlled, allowing for an increased plasma density and ion flux for the same gas pressure and geometrical operating conditions. Analysis of the power deposition profiles and electron distribution functions shows that enhanced electron-sheath heating is responsible for the increased power absorption.

Lafleur, T. [Johannesburg (South Africa); Boswell, R. W. [Space Plasma, Power and Propulsion Group, Research School of Physics and Engineering, Australian National University, Canberra ACT 0200 (Australia); Booth, J. P. [LPP-CNRS, Ecole Polytechnique, 91128 Palaiseau (France)

2012-05-07

7

A modified prony algorithm for estimating sinusoidal frequencies  

Microsoft Academic Search

We investigate the modified Prony algorithm of Osborne and Smyth (1991, 1993) applied to the estimation of the frequency of oscillation of a sinusoidal signal with added white noise, and compare it with the algorithms usually associated with the names of Prony and Pisarenko. We show that the Pisarenko algorithm returns O(N ) consistent estimates, and that the modified Prony

M. S. Mackisack; M. R. Osborne; G. K. Smyth

1994-01-01

8

Estimation of the Frequency of Sinusoidal Signals in Laplace Noise  

Microsoft Academic Search

Accurate estimation of the frequency of sinusoidal signals from noisy observations is an important problem in signal processing applications such as radar, sonar, and telecommunications. In this paper, we study the problem under the assumption of non-Gaussian noise in general and Laplace noise in particular. We prove that the Laplace maximum likelihood estimator is able to attain the asymptotic Cramr-Rao

Ta-Hsin Li; Kai-Sheng Song

2007-01-01

9

Multilevel-Dc-Bus Inverter For Providing Sinusoidal And Pwm Electrical Machine Voltages  

DOEpatents

A circuit for controlling an ac machine comprises a full bridge network of commutation switches which are connected to supply current for a corresponding voltage phase to the stator windings, a plurality of diodes, each in parallel connection to a respective one of the commutation switches, a plurality of dc source connections providing a multi-level dc bus for the full bridge network of commutation switches to produce sinusoidal voltages or PWM signals, and a controller connected for control of said dc source connections and said full bridge network of commutation switches to output substantially sinusoidal voltages to the stator windings. With the invention, the number of semiconductor switches is reduced to m+3 for a multi-level dc bus having m levels. A method of machine control is also disclosed.

Su, Gui-Jia [Knoxville, TN

2005-11-29

10

New ?-? voltage to frequency converter  

Microsoft Academic Search

The voltage to frequency converter (VFC) is an oscillator whose frequency is linearly proportional to the control voltage. There are two common VFC architectures: the current steering multivibrator and the charge-balance VFC. For higher linearity, the charge-balancing method is preferred. The charge balanced VFC may be made in asynchronous or synchronous (clocked) forms. The synchronous charge balanced VFC or \\

Milan Stork

2002-01-01

11

Comparison of Pulsed Sinusoid Radio Frequency Interference Detection Algorithms Using Time and  

E-print Network

Comparison of Pulsed Sinusoid Radio Frequency Interference Detection Algorithms Using Time (ROC) for pulsed sinusoid RFI. Downlink data bandwidth is one of the major design factors-11]. RFI is often localized in time and frequency, relative to the integration times and pre

Ruf, Christopher

12

Converter and Control Design for Very Low-Frequency High-Voltage Test Systems  

E-print Network

Converter and Control Design for Very Low-Frequency High-Voltage Test Systems Zhiyu Cao, Norbert an 85 kV (RMS) sinusoidal test voltage at very low frequency of 0.1 Hz. The resonant converter by experimental tests. Index Terms-- Resonant power conversion, Voltage multipliers, System analysis and design

Paderborn, Universität

13

Foreign Voltages and Frequencies Guide.  

National Technical Information Service (NTIS)

Foreign countries around the world use different electrical standards for voltage and frequency than those of the United States. Electrical equipment designed for 60 Hertz may or may not operate properly in a 50 Hertz environment. Similarly, electrical eq...

L. M. Windingland, S. A. Steele, K. K. Heyen, H. T. Maase, F. H. Holcomb

1997-01-01

14

Frequency-controlled voltage regulator  

NASA Technical Reports Server (NTRS)

Converting input ac to higher frequency reduce size and weight and makes possible unique kind of regulation. Since conversion frequency is above range of human hearing, supply generated on audible noise. It also exploits highfrequency conversion features to regulate its output voltage in novel way. Circuit is inherently short-circuit proof.

Mclyman, W. T.

1980-01-01

15

Genetic algorithms based robust frequency estimation of sinusoidal signals with stationary errors  

Microsoft Academic Search

Genetic algorithms L1-norm estimator Least median estimator Least square estimator Least trimmed estimator Multiple sinusoidal model Outlier-insensitive criterion abstract In this paper, we consider the fundamental problem of frequency estimation of multiple sinusoidal signals with stationary errors. We propose genetic algorithm and outlier-insensitive criterion function based technique for the frequency estimation problem. In the simulation studies and real life data

Amit Mitra; Debasis Kundu

2010-01-01

16

Effects of transient receptor potential-like current on the firing pattern of action potentials in the Hodgkin-Huxley neuron during exposure to sinusoidal external voltage.  

PubMed

Transient receptor potential vanilloid-1 (TRPV1) channels play a role in several inflammatory and nociceptive processes. Previous work showed that magnetic electrical field-induced antinociceptive [corrected] action is mediated by activation of capsaicin-sensitive sensory afferents. In this study, a modified Hodgkin-Huxley model, in which TRP-like current (ITRP) was incorporated, was implemented to predict the firing behavior of action potentials (APs), as the model neuron was exposed to sinusoidal changes in externally-applied voltage. When model neuron is exposed to low-frequency sinusoidal voltage, increased maximal conductance of ITRP can enhance repetitive bursts of APs accompanied by a shortening of inter-spike interval (ISI) in AP firing. The change in ISIs with number of interval is periodic with the phase-locking. In addition, increased maximal conductance of ITRP can abolish chaotic pattern of AP firing in model neuron during exposure to high-frequency voltage. The ISI pattern is converted from irregular to constant, as maximal conductance of ITRP is increased under such high-frequency voltage. Our simulation results suggest that modulation of TRP-like channels functionally expressed in small-diameter peripheral sensory neurons should be an important mechanism through which it can contribute to the firing pattern of APs. PMID:21793354

Chen, Bing-Shuo; Lo, Yi-Ching; Lius, Yen-Chin; Wu, Sheng-Nan

2010-12-31

17

Statistical analysis of MUSIC and subspace rotation estimates of sinusoidal frequencies  

Microsoft Academic Search

Consideration is given to the analysis of the large-sample second-order properties of multiple signal classification (MUSIC) and subspace rotation (SUR) methods, such as ESPRIT, for sinusoidal frequency estimation. Explicit expressions for the covariance elements of the estimation errors associated with either method are derived. These expressions of covariances are then used to analyze and compare the statistical performances of the

Petre Stoica; Torsten Soderstrom

1991-01-01

18

Dynamic voltage and frequency scaling circuits with two supply voltages  

Microsoft Academic Search

AbstractThis paper presents circuits that enable dy- namic voltage and frequency scaling (DVFS) for fine- grained chip multi-processors to reduce both dynamic and leakage power dissipation. Each processor can run on either a high voltage or low voltage power supply, or disconnect from both. Switching between power supplies is performed dynamically, where scaling decisions are based on each processors workload,

Wayne H. Cheng; Bevan M. Baas

2008-01-01

19

A digitalized voltage-to-frequency converter  

Microsoft Academic Search

A new voltage-to-frequency converter, controlled by a quartz crystal oscillator, is described. The principle of operation is based on comparing the input voltage and the mean value of the output pulses, whose magnitude and duration are constant. As the duration of the output pulses is a multiple of the quartz oscillator period for any value of the input voltage, the

B. DJORDJEVICH

1975-01-01

20

Effects of level and frequency on the detection of decrements and increments in sinusoids.  

PubMed

Thresholds for the detection of decrements in level of sinusoidal signals were measured as a function of decrement duration, level (25, 40, 55, and 70 dB SPL) and frequency (250, 1000, and 4000 Hz) in eleven normally hearing subjects. Thresholds for detecting a brief increment in level were also measured. The sinusoids were presented in a background noise intended to mask spectral splatter associated with the decrement or increment. Performance tended to worsen with decreasing frequency, for all decrement durations and for increment detection. Performance also worsened with decreasing level. The results were analyzed using a model consisting of a compressive nonlinearity, a sliding temporal integrator, and a decision device. The analysis indicated that the worsening in performance with decreasing frequency and decreasing level can be attributed partly to increases in the equivalent rectangular duration (ERD) of the temporal integrator, but mainly to changes in the efficiency of the detection process following the temporal integrator; at lower frequencies and levels a larger change is required at the output of the integrator for threshold to be reached. At each frequency, the ERD was relatively invariant with level for levels more than about 20 dB above the absolute threshold. PMID:7790657

Peters, R W; Moore, B C; Glasberg, B R

1995-06-01

21

High precision voltage-to-frequency converter  

Microsoft Academic Search

A bipolar high precision voltage-to-frequency converter is described. The circuit includes an input voltage-to-current conversion stage followed by current-controlled multivibrator. The multivibrator trigger includes a window comparator with a limiter of the output voltage swing, and the timing capacitor discharge current is switched simultaneously with the window comparator bias. This allows to obtain high resolution near both trigger thresholds. The

Sidong Cai; I. M. Filanovsky

1994-01-01

22

A Precision Audio-Frequency Voltage Regulator.  

National Technical Information Service (NTIS)

A source of precisely known alternating voltages is described. The output remains constant to within 0.1% for variation of plus or minus 40% in the input voltage (frequencies between 30 Hz and 4 kHz). The principle of operation is based on negative feedba...

D. Britz, J. S. Jackson, H. H. Bauer

1969-01-01

23

Electronic model of a neuronal sinapsis of voltage to frequency, and frequency to voltage conversion  

Microsoft Academic Search

In this work we present the results of a study of neurons with synapses of the frequency-voltage type response, and the effects of the autosynapse that give us responses of long period. We also present the effects of synapse frequency\\/voltage-voltage\\/frequency in the phenomena of autosynapse in neuron cascades. We also studied the effects of the time constant involved in the

A. Garces; S. Quintana; A. Herrera; M. Bafiuelos; J. Castillo; W. Martinez; A. Padron

1999-01-01

24

A simple, accurate voltage to frequency converter  

Microsoft Academic Search

A simple yet accurate voltage to frequency convertor is described and its performance examined. The unit requires a stable clock frequency. Conversion is linear, predictable, and practically independent of temperature to within errors of measurement (0.05%). Power drain is low (<150 mu W).

P. J. Ross

1974-01-01

25

Flattened comb generation using only phase modulators driven by fundamental frequency sinusoidal sources with small frequency offset.  

PubMed

We propose and experimentally demonstrate a simple scheme to generate flattened optical subcarriers at low insertion loss using only phase modulators driven by fundamental frequency sinusoidal sources. A small frequency offset is introduced in the second stage to obtain phase-insensitive, stable, and flattened subcarriers. Theoretical and numerical analysis with experimental results are carried out on this scheme. Twenty-one stable comb tones with 25 GHz frequency spacing are obtained with power difference less than 3 dB. The good bit-error-ratio performance of 160.8 Gb/s polarization-division-multiplexing quadrature-phase-shift-keying signal carried by one selected subcarrier clearly demonstrates the feasibility of this comb generation scheme. PMID:23455133

Zhang, Junwen; Yu, Jianjun; Chi, Nan; Dong, Ze; Li, Xinying; Shao, Yufeng; Yu, Jianguo; Tao, Li

2013-02-15

26

An accurate voltage-to-frequency converter  

Microsoft Academic Search

A current- or voltage-to-frequency converter is described for converting analogue signals into a pulse form in which the pulse repetition frequency is proportional to the instantaneous signal amplitude. The conversion is linear to within 001% over the frequency range 0-10 kHz (or 0-1 kHz), and to within 01% up to 50 kHz. Thermal stability is comparable.The circuit action is based

P J Unsworth

1969-01-01

27

Effect of sinusoidal forcing of ventilatory volume on avian breathing frequency.  

PubMed

Awake chickens were unidirectionally ventilated at 3.6 l . min-1 with 3.2-4.8% CO2 in air. The air sacs on each side were made confluent and implanted with exit tubes connected to the following three devices: 1) a system of constant-flow generators which remove air at exactly the same rate that it entered the trachea, allowing no port for spontaneous volume changes; 2) a sinusoidal pump to force volume changes in the chicken; and 3) a pressure transducer to record air sac pressure, which reflected the sum of two pressure components, the passive pressure changes created by the pump and the active pressure changes due to breathing efforts. Over a range of pump frequencies, the amplitude of measured air sac pressure changes varied inversely with frequency. Above and below this range, pressure showed a beat pattern, indicating a difference in the frequencies of the two pressure components. Within the range lacking a beat pattern, breathing movements and the pump stroke had the same frequency. This range was greater at increased stroke volume. Breathing efforts worked with the pump at the high end of the range and against the pump at the low end. These findings show further evidence of the presence of a response to volume forcing and fit a previously described volume threshold model. PMID:3932320

Ballam, G O; Clanton, T L; Kaminski, R P; Kunz, A L

1985-09-01

28

Hardware based frequency\\/voltage control of voltage frequency island systems  

Microsoft Academic Search

The ability to do fine grain power management via local volt- age selection has shown much promise via the use of Voltage\\/ Frequency Islands (VFIs). VFI-based designs combine the advantages of using fine-grain speed and voltage control for reducing energy requirements, while allowing for maintain- ing performance constraints. We propose a hardware based technique to dynamically change the clock frequencies

Puru Choudhary; Diana Marculescu

2006-01-01

29

Switched capacitor frequency-to-voltage and voltage-to-frequency converters  

Microsoft Academic Search

Novel switched-capacitor circuits for the frequency-to-voltage (F\\/V) and voltage-to-frequency (V\\/F) conversion are presented. The circuit operation is insensitive to both the offset voltages of op-amps and parasitic capacitances. Therefore, the circuits allow the accurate conversion over the wide dynamic range. Experimental results are also given to confirm the principles of operation.

KENZO WATANABE; HIROKI MATSUMOTO; KAZUNOBU FUJIWARA

1986-01-01

30

Investigation of time-resolved single detector Doppler global velocimetry using sinusoidal laser frequency modulation  

NASA Astrophysics Data System (ADS)

We present a new Doppler global velocimetry (DGV) technique that is based on sinusoidal laser frequency modulation: FM-DGV. DGV is an optical method to measure two-dimensional velocity fields in fluid flows. The measurement principle is based on measuring the Doppler shift of the laser frequency with the use of an absorption cell converting frequency variations into intensity variations. In order to measure the scattered light intensity, conventional DGV systems use a signal and a reference camera. Using the FM-DGV technique, no additional reference camera is required. Thus significant error sources can be eliminated, e.g. image misalignment errors, which can limit the performance of conventional DGV. In this paper, a comparison between both DGV systems and an error analysis of the FM-DGV system is given. The parameter optimization of the FM-DGV is discussed as well. A minimum measured standard deviation of 0.02 m s-1 was achieved. Measurement results of applications to a rotating glass disc as a calibration object, a free jet flow and a laminar boundary layer flow are presented to demonstrate the ability of FM-DGV also for low-speed and unsteady flow conditions.

Fischer, Andreas; Bttner, Lars; Czarske, Jrgen; Eggert, Michael; Grosche, Gesine; Mller, Harald

2007-08-01

31

Linear voltage to frequency and voltage to pulse width converters using unijunction transistors  

Microsoft Academic Search

Applications of semiconductors to power systems, for example to thyristor inverter frequency control, require voltage to frequency conversion in a pulse mode, particularly at low frequencies. Voltage to pulse width conversion might be necessary for sampling pulses. Voltage to frequency and voltage to pulse width converters with almost linear characteristics utilizing unijunction transistors have been designed and investigated. Arrangements for

OM SWARUP; H. BANERJEE

1972-01-01

32

Response characteristics of single units in the inferior colliculus of mustache bats to sinusoidally frequency modulated signals  

Microsoft Academic Search

1.The discharge properties of single units in the inferior colliculus of the mustache bat,Pteronotus parnellii, were evaluated with tone bursts and sinusoidal frequency modulated (SFM) stimuli. The SFM signals were designed to mimic the modulation patterns imposed upon the echoes reflected from the beating wings of flying insects.2.Two groups of neurons were distinguished on the basis of their best frequencies

Robert D. Bodenhamer; George D. Pollak

1983-01-01

33

Piezoelectric cantilever voltage-to-frequency converter  

Microsoft Academic Search

A micromachined piezoelectric cantilever acoustic device that functions as a microspeaker and a voltage-to-frequency converter has been designed, fabricated and tested. The 2 2 0.0047 mm3 cantilever has a 1.3-?m-thick zinc oxide (ZnO) piezoelectric thin film on a supporting layer of LPCVD low-stress silicon nitride. When measured with 8 VP-P (peak-peak) input drive, the sound pressure level (SPL)

Seung S. Lee; Richard M. White

1998-01-01

34

Stable differential voltage to frequency converter with low supply voltage and frequency offset control  

Microsoft Academic Search

In this paper, the circuit for a new bipolar differential voltage-to-frequency converter is presented. The circuit operation and the calculation of the operating frequency are described. The circuit design is also realized using Zetex transistor array integrated circuits and a 3.3-V power supply. This circuit incorporates an adjustable operating frequency via an external capacitor. The operating frequency varied from 15

D. McDonagh; K. I. Arshak

1998-01-01

35

Broadband linear high-voltage amplifier for radio frequency ion traps.  

PubMed

We developed a linear high-voltage amplifier for small capacitive loads consisting of a high-voltage power supply and a transistor amplifier. With this cost-effective circuit including only standard parts sinusoidal signals with a few volts can be amplified to 1.7 kVpp over a usable frequency range at large-signal response spanning four orders of magnitude from 20 Hz to 100 kHz under a load of 10 pF. For smaller output voltages the maximum frequency shifts up to megahertz. We test different capacitive loads to probe the influence on the performance. The presented amplifier is sustained short-circuit proof on the output side, which is a significant advantage over other amplifier concepts. The amplifier can be used to drive radio frequency ion traps for single charged nano- and microparticles, which will be presented in brief. PMID:25430133

Kuhlicke, Alexander; Palis, Klaus; Benson, Oliver

2014-11-01

36

Phasors and Sinusoids  

NSDL National Science Digital Library

This interactive website from professor James A. Svoboda of Clarkson University describes phasors and sinusoids. Interactive graphs depict frequency and time domains. Users may change the phasor and see the resulting change in the sinusoid. You may also click inside the Frequency Domain box to see the change in the Time Domain.

Svoboda, James A.

2010-07-12

37

Journal of Neuroscience Methods 99 (2000) 129135 Low frequency voltage clamp: recording of voltage transients at  

E-print Network

configurations do not allow recording voltage transients while holding the average voltage fixed. One would likeJournal of Neuroscience Methods 99 (2000) 129­135 Low frequency voltage clamp: recording of voltage transients at constant average command voltage Florian Peters, Arne Gennerich, Dirk Czesnik, Detlev Schild

38

Dynamic Voltage and Frequency Scaling for Scientific Applications #  

E-print Network

Dynamic Voltage and Frequency Scaling for Scientific Applications # Chung­Hsing Hsu and Ulrich the physical environment. Dynamic voltage and frequency scaling (DVFS) has been recognized as an e clock frequencies and voltage levels. These values may be changed during the course of program execution

Kremer, Ulrich

39

CompilerDirected Dynamic Frequency and Voltage Scheduling #  

E-print Network

Compiler­Directed Dynamic Frequency and Voltage Scheduling # Chung­Hsing Hsu 1 , Ulrich Kremer 1, New Jersey, USA mhsiao@ece.rutgers.edu Abstract. Dynamic voltage and frequency scaling has been strategy that identifies opportunities for dynamic voltage and frequency scaling of the CPU without

Kremer, Ulrich

40

CompilerDirected Dynamic Frequency and Voltage Scheduling #  

E-print Network

Compiler­Directed Dynamic Frequency and Voltage Scheduling # Chung­Hsing Hsu 1 , Ulrich Kremer 1. This paper discusses a compilation strategy that identifies opportunities for dynamic voltage and frequency­time voltage and frequency scaling for single loop nests. The compiler not only generates code for the input

Kremer, Ulrich

41

Digitally programmable voltage-to-frequency converter  

NASA Astrophysics Data System (ADS)

The author presents a novel design approach for a VFC (voltage-to-frequency converter) based on a digital technique which utilizes an analog-to-digital converter, programmable read-only-memory, latch, divide-by-n chip, and associated control circuitry. The unique aspect of this design is the fact that the ratio between the maximum and minimum frequency rates is programmable by the user, and the performance is highly repeatable. This technique was developed in order to provide a drive circuitry for a 5-b digital phase shifter which was being serrodyned in order to create deception jamming functions for electronic countermeasures applications. A circuit diagram of the digital VFC is presented.

Madni, Asad M.

42

Electric current flow through human skin at power frequency voltages  

PubMed Central

Carter, A.O., and Morley R. (1969).Brit. J. industr. Med.,26, 217-223. Electric current flow through human skin at power frequency voltages. Alternating power voltages were applied to small pieces of living skin. Current and voltage were recorded continuously using voltages from 25 V to 250 V. At the lower voltages the skin appeared unaffected, but rapid destruction occurred at the higher voltages. It is concluded that skin impedance, whilst being extremely variable on account of many physical factors, is dependent on voltage and time of application in the range where dangerous electric shock occurs to human beings at power frequencies. PMID:5794946

Carter, A. O.; Morley, R.

1969-01-01

43

An amorphous alloy core medium frequency magnetic-link for medium voltage photovoltaic inverters  

NASA Astrophysics Data System (ADS)

The advanced magnetic materials with high saturation flux density and low specific core loss have led to the development of an efficient, compact, and lightweight multiple-input multiple-output medium frequency magnetic-link. It offers a new route to eliminate some critical limitations of recently proposed medium voltage photovoltaic inverters. In this paper, a medium frequency magnetic-link is developed with Metglas amorphous alloy 2605S3A. The common magnetic-link generates isolated and balanced multiple DC supplies for all of the H-bridge inverter cells of the medium voltage inverter. The design and implementation of the prototype, test platform, and the experimental test results are analyzed and discussed. The medium frequency non-sinusoidal excitation electromagnetic characteristics of alloy 2605S3A are also compared with that of alloy 2605SA1. It is expected that the proposed new technology will have great potential for future renewable power generation systems and smart grid applications.

Rabiul Islam, Md.; Guo, Youguang; Wei Lin, Zhi; Zhu, Jianguo

2014-05-01

44

Integrating dynamic voltage\\/frequency scaling and adaptive body biasing using test-time voltage selection  

Microsoft Academic Search

Adaptive body biasing is a promising technique for address- ing increasing process variability, but it also provides new opportunities for reducing power when combined with dy- namic voltage\\/frequency scaling. Limitations of existing ABB\\/DVFS proposals are explored, and a new scheme, test- time voltage selection (TTVS), is presented. By delaying the mapping between frequency and supply voltage until test, variability information

Alyssa Bonnoit; Sebastian Herbert; Diana Marculescu; Lawrence T. Pileggi

2009-01-01

45

A square-rooting voltage-to-frequency converter  

Microsoft Academic Search

A clock-controlled voltage-to-frequency converter in which the output frequency is proportional to the square root of the input voltage is described and a detailed error analysis is presented. Accuracies of about 0.02% of full-scale for the voltage input range from 1 mV to 10 V have been achieved using commercially-available CMOS components in good agreement with theoretical expectations

F. N. Trofimenkoff; F. Sabouri; Jichang Qin; J. W. Haslett

1997-01-01

46

Switched-capacitor frequency-to-voltage and voltage-to-frequency converters based on charge-balancing principle  

Microsoft Academic Search

Switched-capacitor frequency-to-voltage and voltage-to-frequency converters integrable onto a small chip area are developed. The conversion is insensitive to parasitic capacitances, capacitance ratio, offset voltages, and finite open-loop gains of op amps. Therefore, both converters allow accurate conversion over a wide dynamic range. The authors describe the circuit configurations, the principles of operation, and the experimental results obtained by breadboard converters

Hiroki Matsumoto; Kenzo Watanabe

1988-01-01

47

Quartz crystal microbalance based on passive frequency to voltage converter  

SciTech Connect

In dynamics of evaporation or drying of microdrops from a solid surface, a faster and precise quartz crystal microbalance (QCM) is needed. The fast QCM based on frequency to voltage converter is an attractive and powerful tool in the investigation of the dynamic regime of evaporation to translate the frequency shift in terms of a continuous voltage change. The frequency shift monitoring in fast QCM applications is a real challenge for electronic processing interface. Originally developed as a frequency shift processing interface, this novel passive frequency to voltage converter can produce faster, stable, and accurate results in regard to the QCM sensor behavior. In this article, the concept and circuit of passive frequency to voltage converter will be explained followed by static and dynamic characterization. Experimental results of microdrops evaporation will be given.

Burda, Ioan; Tunyagi, Arthur [Department of Physics, Babes-Bolyai University, Cluj-Napoca, 400084 (Romania)

2012-02-15

48

Adaptive rejection of stochastic and deterministic sinusoidal disturbances with unknown frequency  

Microsoft Academic Search

In this paper, an adaptive control algorithm is proposed to reject unknown deterministic disturbances and minimize output variance. The proposed algorithm contains two adaptive control actions. One rejects a set of unidentified deterministic disturbances by an adaptive internal model with online frequency identification. The other minimizes the output variance using an adaptive finite impulse response filter. The stability and performance

Yigang Wang; Kevin C. Chu; Tsu-Chin Tsao

2009-01-01

49

BIOLOGICAL INFLUENCES OF LOW-FREQUENCY SINUSOIDAL ELECTROMAGNETIC SIGNALS ALONE AND SUPERIMPOSED ON RF CARRIER WAVES  

EPA Science Inventory

The report describes in a historical context the experiments that have been performed to examine the biological responses caused by exposure to low frequency electromagnetic radiation directly or as modulation of RF carrier waves. A detailed review is provided of the independentl...

50

High voltage, high frequency conversion transformer  

Microsoft Academic Search

A 25 kW, 15 kV output, 50 kHz transformer with 100 kV primary to secondary isolation is described. The transformer will be the central element of a resonant inverter. Six of these resonant inverter outputs will be connected in series to produce 90 kV for an airborne application. The transformer and high voltage will be in an SF6 atmosphere. Unique

Charles S. Kerfoot; Milton J. Greif

1997-01-01

51

A voltage and frequency droop control method for parallel inverters  

Microsoft Academic Search

In this paper, a new control method for the parallel operation of one or several inverters in an island grid or the mains is described. Frequency and voltage control, including mitigation of voltage harmonics, are achieved without the need for any common control circuitry or communication between the inverters. Each inverter supplies a current that is the result of the

K. De Brabandere; B. Bolsens; J. Van den Keybus; A. Woyte; J. Driesen; R. Belmans; K. U. Leuven

2004-01-01

52

A Voltage and Frequency Droop Control Method for Parallel Inverters  

Microsoft Academic Search

In this paper, a new control method for the parallel operation of inverters operating in an island grid or connected to an infinite bus is described. Frequency and voltage control, including mitigation of voltage harmonics, are achieved without the need for any common control circuitry or communication between inverters. Each inverter supplies a current that is the result of the

K.. De Brabandere; B.. Bolsens; J.. Van den Keybus; A.. Woyte; J.. Driesen; R.. Belmans

2007-01-01

53

46 CFR 111.01-17 - Voltage and frequency variations.  

Code of Federal Regulations, 2013 CFR

...01-17 Section 111.01-17 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS General 111.01-17 Voltage and frequency variations....

2013-10-01

54

High frequency AC power converter for low voltage circuits  

E-print Network

This thesis presents a novel AC power delivery architecture that is suitable for VHF frequency (50-100MHz) polyphase AC/DC power conversion in low voltage integrated circuits. A complete AC power delivery architecture was ...

Salazar, Nathaniel Jay Tobias

2012-01-01

55

New ?-? Voltage to Frequency Converter Analysis and Applications  

Microsoft Academic Search

Voltage to frequency converter (VFC) is an oscillator whose frequency is linearly proportional to control voltage. There are\\u000a two common VFC architectures: the current steering multivibrator and the charge-balance VFC. For higher linearity, the charge-balancing\\u000a method is preferred. The charge balanced VFC may be made in asynchronous or synchronous (clocked) forms. The synchronous charge\\u000a balanced VFC or sigma delta Sigma-Delta

Milan Stork

2006-01-01

56

Dynamic decoupling of voltage frequency controlled induction motors  

Microsoft Academic Search

A new nonlinear control scheme for voltage frequency controlled (VFC) induction motors is presented, based on dynamic state-feedback. The proposed approach allows to design an input-output decoupling controller for motor torque and flux, using as inputs the amplitude and the frequency of the supply voltage. The closed-loop system contains an unobservable sink. The dynamics of this part is stable and

Alessandro De Luca; Giovanni Ulivi

57

Speed and voltage selection for GALS systems based on voltage\\/frequency islands  

Microsoft Academic Search

Due to increasing clock speeds and shrinking technologies, dis- tributing a single global clock signal throughout a chip is be- coming a difficult and challenging proposition. In this paper, we address the problem of energy optimal local speed and volt- age selection in frequency\\/voltage island based systems under given performance constraints. Our results show that static voltage and speed assignment

Koushik Niyogi; Diana Marculescu

2005-01-01

58

Single and joint actions of noise and sinusoidal whole body vibration on TTS 2 values and low frequency upright posture sway in men  

Microsoft Academic Search

In the present study the changes in the TTS2 values and body upright posture sway were examined after exposure of subjects (n =10) to stable broadband (white) noise (90 dB) alone, to sinusoidal vibration alone [directed vertically at the whole body (Z axis)], and to simultaneous exposure combinations of noise and vibrations of the same type. The frequency of the

Olavi Manninen; Ari Ekblom

1984-01-01

59

A versatile monolithic voltage-to-frequency converter  

Microsoft Academic Search

Voltage-to-frequency (V-F) conversion is achieved with high linearity (0.02 percent) using a precise multivibrator with an 80-dB dynamic range. The IC operates from a single, low-current supply and can accept millivolt signals. A unique thermometer output permits direct conversion of temperature to frequency.

BARRIE GILBERT

1976-01-01

60

Low-frequency sinusoidal galvanic stimulation of the left and right vestibular nerves reveals two peaks of modulation in muscle sympathetic nerve activity  

Microsoft Academic Search

Studies previously performed in our laboratory have shown that sinusoidal galvanic vestibular stimulation (sGVS), a means\\u000a of selectively modulating vestibular input without affecting other inputs, can cause partial entrainment of muscle sympathetic\\u000a nerve activity (MSNA) at frequencies ranging from 0.2 to 2.0Hz. Here we test the effect of sGVS on sympathetic outflow when\\u000a stimulating the vestibular system at lower frequencies.

Elie Hammam; Cheree James; Tye Dawood; Vaughan G. Macefield

61

Voltage-To-Frequency Converter For Pressure Calibration  

NASA Technical Reports Server (NTRS)

Measurements of pressures on walls of wind tunnels and on surfaces of models in wind tunnels made with help of electronically scanned pressure-measurement (ESP) system. Voltage-to-frequency converter circuit, designed to convert 0- to 5-Vdc analog output voltage from high-line-pressure, low-differential-pressure standard to required frequency range. Enables selection of wider variety of high-accuracy pressure standards to enhance accuracy of measurement of ESP instrumentation while requiring little modification of manufacturer's system and no modification of operating software of system. Useful primarily in wind-tunnel instrumentation and readily adaptable to commercial instruments currently in use.

Sealey, Bradley S.; Mitchell, Michael

1993-01-01

62

Total Ionizing Dose Effects on Voltage-to-Frequency Converters  

NASA Technical Reports Server (NTRS)

This paper discusses total dose effects on voltage-to-frequency converters which impose different requirements on internal circuitry, and are also very high-precision devices (for example, linearity is typically specified between 0.002 and 0.05%).

Lee, C.; Johnston, A.; Rax, B.

1998-01-01

63

Coordination of Voltage and Frequency Feedback in Load-Frequency Control Capability of Wind Turbine  

E-print Network

Coordination of Voltage and Frequency Feedback in Load-Frequency Control Capability of Wind Turbine-Frequency Control (LFC) is gradually shifted to Variable Speed Wind Turbines (VSWTs). In order to equip VSWT@et.aau.dk Abstract--In near future, with high penetration of Wind Energy (WE) in power system, the burden of Load

Silva, Filipe Faria Da

64

Alternative solution of direct frequency conversion for AC drives  

Microsoft Academic Search

A new approach to real approximation of an ideal sinusoidal frequency conversion process is put forward. This enables the output frequency range of line-commutated direct frequency converters to be expanded up to the value of input frequency. This is achieved by the application of a low frequency value sinusoidal modulating function and the replacement of input voltage and modulating function

L. Ribickis; M. Liepins; L. Rutmanis; J. Stabulnieks

1993-01-01

65

Synthesis of Medium Voltage dc-to-dc Converters From Low-Voltage, High-Frequency PWM Switching Converters  

Microsoft Academic Search

Low-voltage dc-to-dc power conversion is a very mature industry which uses high-frequency pulsewidth modulation (PWM) switching techniques. The passive and active components needed to build low-voltage dc-to-dc converters are highly available, affordable and constantly improving. In this paper, a very simple and systematic method of using a large number of low-voltage, high-frequency PWM converters to synthesize highly redundant, medium voltage

Vatche Vorperian

2007-01-01

66

MONOLITHIC VOLTAGE-TO-FREQUENCY CONVERTERS MACROMODEL DEVELOPMENT  

Microsoft Academic Search

A macromodel of monolithic Voltage-to-Frequency Converter (VFC) for the simulator PSpice A\\/D is proposed. For creating the model, simplification and build-up techniques known from modelling operational amplifiers have been adapted. This generalized model is independent from actual technical realizations and is based upon compromises regarding the representation of exact circuit structure in the model. The proposed VFC model accurately predict

Ivailo Milanov Pandiev

67

A voltage to frequency converter for astronomical photometry  

NASA Technical Reports Server (NTRS)

A voltage to frequency converter (VFC) for general use with photomultipliers is described. For high light levels, when the dead-time corrections for a photon counter would be excessive, the VFC maintains a linear response and allows the recording of data at high time resolution. Results of laboratory tests are given for the signal-to-noise characteristics, linearity, stability, and transient response of the VFC when used in conjunction with EMI 9658 and RCA C31034 photomultipliers.

Dunham, E.; Elliot, J. L.

1978-01-01

68

Variation-aware dynamic voltage\\/frequency scaling  

Microsoft Academic Search

Fine-grained dynamic voltage\\/frequency scaling (DVFS) is an important tool in managing the balance between power and performance in chip-multiprocessors. Although manufacturing process variations are giving rise to significant core-to-core variations in power and performance, traditional DVFS controllers are unaware of these variations. Exploiting the different power\\/performance profiles of the cores can significantly improve energy-efficiency. Two hardware DVFS control algorithms are

Sebastian Herbert; Diana Marculescu

2009-01-01

69

A lowvoltage CMOS transconductor for very high frequencies  

Microsoft Academic Search

This paper presents a pseudo-differential continuous time transconductor for applications in low-voltage systems over the very high frequency range. By using a 0.8 m CMOS process, the transconductor consumes less than 1.5 mW from a 2.7 V supply. A prototype third-order 60 MHz elliptic lowpass ladder filter with a transmission zero at 200 MHz confirms the feasibility of the proposed

S. Celma; J. Sabadell; C. Aldea; P. A. Martinez

1999-01-01

70

Time dependent behaviors of ion-ion plasmas exposed to various voltage waveforms in the kilohertz to megahertz frequency range  

SciTech Connect

An ion-ion plasma, situated between two parallel electrodes, is studied with the use of a time dependent one-dimensional particle-in-cell Monte-Carlo collisions model. This plasma consists of only positively and negatively singly charged ions with the same order of mass and temperature (the electron density is zero). The right electrode is grounded, and the left electrode is biased with a voltage waveform varying from sinusoidal to square with the frequency in the kHz to MHz range. The sheath evolution and the particle flux towards the electrodes, as a function of both space and time, are investigated for the various waveforms and frequencies. The sheath evolution has a strong influence on the time averaged ion energy distribution function (IEDF). The IEDF is broad with a low energy tail for low frequency sinusoidal biases (25 kHz) while peaked at low energy for higher frequencies (2 MHz). For square waveforms, the IEDF is mono-energetic with some broadening when the rise time is faster than the typical time to establish the steady state sheath formation (<0.3 {mu}s).

Oudini, N.; Raimbault, J.-L.; Chabert, P.; Aanesland, A. [Laboratoire de Physique des Plasmas, CNRS, Ecole Polytechnique, 91128 Palaiseau Cedex (France); Garrigues, L. [LAPLACE (Laboratoire Plasma et Conversion d'Energie), Universite de Toulouse, UPS, INPT Toulouse, 118 route de Narbonne, F-31062 Toulouse cedex 9 (France); CNRS, LAPLACE, F-31062 Toulouse (France); Meige, A. [PRESANS/X-Technologies/Ecole Polytechnique, 91128 Palaiseau Cedex (France)

2012-10-15

71

Voltage and frequency control with reduced switch integrated voltage source converter for IAG in wind energy conversion system  

Microsoft Academic Search

This paper deals with a voltage and frequency controller (VFC) of a stand-alone wind energy conversion system using an isolated asynchronous generator (IAG) feeding three-phase four-wire loads. The reference generator currents are estimated using the power balance theory to control the voltage and frequency of IAG system. Two-leg reduced switch integrated voltage source converter (VSC) with a battery energy storage

Bhim Singh; Shailendra Sharma; Ambrish Chandra; K. Al Haddad

2010-01-01

72

Voltage and frequency stabilisation of wind-diesel hybrid remote area power systems  

Microsoft Academic Search

This paper presents voltage and frequency stabilisation methods of a hybrid wind-diesel power system. A technique for power sharing between a wind energy conversion system and a diesel generator system is also addressed during the wind-diesel hybrid operation. The output voltage and frequency of the wind energy conversion system is controlled by a load side converter. The voltage and frequency

Abu Mohammad Osman Haruni; Ameen Gargoom; M. E. Haque; M. Negnevitsky

2009-01-01

73

Advanced coupled voltage-frequency control for power efficient DVFS management  

E-print Network

Advanced coupled voltage-frequency control for power efficient DVFS management C. Albea1,2 , Diego-topic in complex System-on-Chip (SoC) designs. In the context of advanced technologies, Dynamic Voltage-Frequency are composed of independent actuators con- trolling the applied voltage and clock frequency. A predefined

Boyer, Edmond

74

Scheduling Processor Voltage and Frequency in Server and Cluster Systems Ramakrishna Kotla,  

E-print Network

Scheduling Processor Voltage and Frequency in Server and Cluster Systems Ramakrishna Kotla of processor frequency and voltage scaling as a way to reduce processor power, which is often the single most important contributor to system-level power consumption. In the past, dynamic voltage and frequency scaling

Freeh, Vincent

75

Voltage and frequency dependence of prestin-associated charge transfer Sean X. Sun a,c  

E-print Network

Voltage and frequency dependence of prestin-associated charge transfer Sean X. Sun a,c , Brenda-diffusion model to reveal the frequency and voltage dependence of electric charge transfer by prestin to prestin. We found a voltage- and frequency-dependent phase shift between the transferred charge

Sun, Sean

76

PEV-Based Combined Frequency and Voltage Regulation for Smart Grid  

E-print Network

PEV-Based Combined Frequency and Voltage Regulation for Smart Grid Chenye Wu, Student Member, IEEE be solved for optimal combined offering of frequency and voltage regulation by PEVs. They address both day management, reactive power compensation, ancillary ser- vices, frequency regulation, voltage regulation

Huang, Jianwei

77

Exploiting Space Diversity and Dynamic Voltage Frequency Scaling in Multiplane Network-on-Chips  

E-print Network

Exploiting Space Diversity and Dynamic Voltage Frequency Scaling in Multiplane Network. In this paper, we approach NoCs power optimization through Dynamic Voltage and Frequency Scaling (DVFS) under the hypothesis that two NoC planes are available, each with a different voltage supply and clock frequency. We

78

Voltage and Frequency Stability of Weak Power Distribution Networks with Droop-Controlled  

E-print Network

Voltage and Frequency Stability of Weak Power Distribution Networks with Droop to improve power quality and reliability of power grids. These DG's, however, may cause voltage and frequency with rated power level (stressful). Weak networks complicate voltage stability and frequency synchronization

Lemmon, Michael

79

Determining the Minimum Energy Consumption using Dynamic Voltage and Frequency Scaling  

E-print Network

Determining the Minimum Energy Consumption using Dynamic Voltage and Frequency Scaling Min Yeol microprocessors allow voltage and frequency scaling, which enables a sys- tem to reduce CPU power and performance when the CPU is not on the critical path. When properly directed, such dynamic voltage and frequency

Young, R. Michael

80

To appear in IEEE Transactions on VLSI Systems 1 Dynamic Voltage and Frequency Scheduling  

E-print Network

To appear in IEEE Transactions on VLSI Systems 1 Dynamic Voltage and Frequency Scheduling@ceng.usc.edu). Abstract-- An adaptive method to perform dynamic voltage and frequency scheduling (DVFS) for minimizing, the proposed DVFS system makes use of adaptive update intervals for optimal frequency and voltage scheduling

Pedram, Massoud

81

CompilerDirected Dynamic Voltage/Frequency Scheduling for Energy Reduction in Microprocessors #  

E-print Network

Compiler­Directed Dynamic Voltage/Frequency Scheduling for Energy Reduction in Microprocessors conditioning of computing and data centers. We will discuss the benefits of compile­time voltage and frequency scaling where the compiler identifies promising program regions for CPU voltage and CPU frequency scal

Kremer, Ulrich

82

SRF theory for voltage and frequency control of IAG based wind power generation  

Microsoft Academic Search

This paper deals with the control of voltage and frequency of an autonomous wind power generation based on isolated asynchronous generator (IAG) feeding three-phase four-wire loads. The proposed control scheme is using the synchronous reference frame (SRF) theory based current detection. The proposed voltage and frequency controller (VFC) consists of a three leg voltage source converter (VSC) with a battery

Bhim Singh; Shailendra Sharma

2009-01-01

83

Power Balance Theory Based Voltage and Frequency Control for IAG in Wind Power Generation  

Microsoft Academic Search

This paper deals with an application of the power balance theory in a voltage and frequency controller (VFC) of an autonomous wind power generation using an isolated asynchronous generator (IAG) feeding three-phase four wire loads. The reference generator currents are estimated using the power balance theory to control the voltage and frequency of IAG system. Three-leg voltage source converter (VSC)

Bhim Singh; Shailendra Sharma

2009-01-01

84

Digital power factor meter design based on voltage-to-frequency conversion  

Microsoft Academic Search

This paper describes the development of an electronic power factor meter to replace the conventional electrodynamic type. The design is based on voltage-to-frequency conversion and digital counting techniques. Two DC signals are generated : the first proportional to the peak voltage Vm and the second proportional to Vm cos ?. These two signals are applied to two voltage-to-frequency converters (VFC).

M. S. M. AL-ANI; M. A. H. ABDUL-KARIM

1982-01-01

85

ANALOG VLSI DESIGN OF MULTI-PHASE VOLTAGE DOUBLERS WITH FREQUENCY REGULATION  

E-print Network

ANALOG VLSI DESIGN OF MULTI-PHASE VOLTAGE DOUBLERS WITH FREQUENCY REGULATION Fengjing Qiu, Janusz A show that the output voltage is 3.995 times the power supply. By using the frequency regulator@bobcat.ent.ohiou.edu ABSTRACT This paper proposes a new organization of charge pump circuits based on a voltage doubler [2

Starzyk, Janusz A.

86

Solid State Voltage and Frequency Controller for a Stand Alone Wind Power Generating System  

Microsoft Academic Search

This paper deals with the voltage and frequency controller of a wind turbine driven isolated asynchronous generator. The proposed voltage and frequency controller consists of an insulated gate bipolar junction transistor based voltage source converter along-with battery energy storage system at its dc link. The proposed controller is having bidirectional active and reactive powers flow capability by which it controls

Bhim Singh; Gaurav Kumar Kasal

2008-01-01

87

Design of a resonant inverter with variable voltage and constant frequency  

Microsoft Academic Search

A series inverter circuit is proposed that provides constant output frequency and a wide range of output voltage control. This circuit overcomes one of the major disadvantages of series inverters normally providing only a small range of voltage control at varying frequency. The circuit is a combination of two basic inverter circuits. The voltage control is achieved by phase-shifting the

R. Bonert

1988-01-01

88

Induction generator based system providing regulated voltage with constant frequency  

Microsoft Academic Search

A PWM voltage-source inverter is used in order to improve the electrical characteristics of an isolated induction generator. The electronic converter allows achievement of a better system behavior in many aspects: voltage regulation, frequeney stabilization and reactive power compensation. The PWM inverter DC voltage is the control variable of the generator speed governor, therefore the system power balance and the

E. G. Marra; J. A. Pomilio

1999-01-01

89

A new topology for high voltage, high frequency transformers  

Microsoft Academic Search

When a DC high voltage needs to be obtained from low voltage inputs (mains voltage), the necessary power converter needs a high value for its transformation ratio; consequently, a large number of turns is often necessary for secondary windings and some parasitics appear (large leakage inductance and large capacitance). Thus, it is usual to design a resonant converter to include

M. A. Perez; C. Blanco; M. Rico; F. F. Linera

1995-01-01

90

A Voltage-Frequency Island Aware Energy Optimization Framework for Networks-on-Chip  

Microsoft Academic Search

In this paper, we present a partitioning, mapping, routing and interface optimization framework for energy-effi- cient voltage-frequency island (VFI) based networks-on-chip. Unlike the recent work that performs tile partitioning only with voltage-frequency assignment for a given mesh network layout, our framework consists of three key VFI-aware components, i.e., VFI-aware core partitioning with voltage and frequency assignment, VFI-aware mapping, and VFI-aware

Wooyoung Jang; David Z. Pan

2011-01-01

91

A Voltage and Frequency Controller for Self-Excited Induction Generators  

Microsoft Academic Search

This article describes a controller for voltage and frequency control of self-excited induction generator (SEIG) supplying static\\/dynamic, balanced\\/unbalanced loads. The controller is a combination of a three-phase insulated gate bipolar transistor (IGBT) based current controlled voltage source inverter (CC-VSI) and a high frequency DC chopper, which keeps the generated voltage and frequency constant in spite of change in consumer loads.

Bhim Singh; S. S. Murthy; Sushma Gupta

2006-01-01

92

Voltage and Frequency Controllers for an Asynchronous Generator-Based Isolated Wind Energy Conversion System  

Microsoft Academic Search

This paper presents a state of art on voltage and fre- quency controllers (VFCs) for isolated asynchronous generators (IAGs) for standalone wind energy conversion systems. In wind turbine-driven IAG, magnitude and frequency of the generated voltage vary because of varying consumer loads and wide fluctua- tion in wind speeds. Therefore, new types of VF controllers based on a voltage source

Gaurav Kumar Kasal; Bhim Singh

2011-01-01

93

Characterization of the frequency and muscle responses of the lumbar and thoracic spines of seated volunteers during sinusoidal whole body vibration.  

PubMed

Whole body vibration has been postulated to contribute to the onset of back pain. However, little is known about the relationship between vibration exposure, the biomechanical response, and the physiological responses of the seated human. The aim of this study was to measure the frequency and corresponding muscle responses of seated male volunteers during whole body vibration exposures along the vertical and anteroposterior directions to define the transmissibility and associated muscle activation responses for relevant whole body vibration exposures. Seated human male volunteers underwent separate whole body vibration exposures in the vertical (Z-direction) and anteroposterior (X-direction) directions using sinusoidal sweeps ranging from 2 to 18?Hz, with a constant amplitude of 0.4?g. For each vibration exposure, the accelerations and displacements of the seat and lumbar and thoracic spines were recorded. In addition, muscle activity in the lumbar and thoracic spines was recorded using electromyography (EMG) and surface electrodes in the lumbar and thoracic region. Transmissibility was determined, and peak transmissibility, displacement, and muscle activity were compared in each of the lumbar and thoracic regions. The peak transmissibility for vertical vibrations occurred at 4?Hz for both the lumbar (1.55??0.34) and thoracic (1.49??0.21) regions. For X-directed seat vibrations, the transmissibility ratio in both spinal regions was highest at 2?Hz but never exceeded a value of 1. The peak muscle response in both spinal regions occurred at frequencies corresponding to the peak transmissibility, regardless of the direction of imposed seat vibration: 4?Hz for the Z-direction and 2-3?Hz for the X-direction. In both vibration directions, spinal displacements occurred primarily in the direction of seat vibration, with little off-axis motion. The occurrence of peak muscle responses at frequencies of peak transmissibility suggests that such frequencies may induce greater muscle activity, leading to muscle fatigue, which could be a contributing mechanism of back pain. PMID:25010637

Baig, Hassam A; Dorman, Daniel B; Bulka, Ben A; Shivers, Bethany L; Chancey, Valeta C; Winkelstein, Beth A

2014-10-01

94

Experimental Verification of Positive Correlation Characteristics by Generalized High-frequency Voltage Injection Method  

NASA Astrophysics Data System (ADS)

Through experiments, this paper newly validates analytical correlation characteristics between rotor and major-axis phases of high-frequency current trajectory caused by injection of the generalized high-frequency ellipse voltage.

Kumomo, Hidekazu; Shinnaka, Shinji

95

Lower operation voltage in dual-frequency cholesteric liquid crystals based on the thermodielectric effect.  

PubMed

Dual-frequency cholesteric liquid crystal (DFCLC) devices characteristically require high operation voltage, which hinders their further development in thin-film-transistor driving. Here we report on a lower-voltage switching method based on the thermodielectric effect. This technique entails applying a high-frequency voltage to occasion dielectric oscillation heating so to induce the increase in crossover frequency. The subsequent change in dielectric anisotropy of the DFCLC allows the switching, with a lower operation voltage, from the planar state to the focal conic or homeotropic state. The temperature rise incurred by the dielectric heating is described. PMID:24104303

Hsiao, Yu-Cheng; Lee, Wei

2013-10-01

96

Sigma-Delta Voltage to Frequency Converter With Phase Modulation Possibility  

Microsoft Academic Search

Voltage to frequency converter (VFC) is an oscillator whose frequency is linearly proportional to control voltage. There are two common VFC architectures: the current steering multivibrator and the charge-balance VFC. For higher linearity, the charge-balancing method is preferred. The charge balanced VFC may be made in asynchronous or synchronous (clocked) forms. The synchronous charge balanced VFC or \\

Milan STORK

97

Profile-based dynamic voltage and frequency scaling for a multiple clock domain microprocessor  

Microsoft Academic Search

A Multiple Clock Domain (MCD) processor addresses the challenges of clock distribution and power dissipation by dividing a chip into several (coarse-grained) clock domains, allowing frequency and voltage to be reduced in domains that are not currently on the application's critical path. Given a reconfiguration mechanism capable of choosing appropriate times and values for voltage\\/frequency scaling, an MCD processor has

Grigorios Magklis; Michael L. Scott; Greg Semeraro; David H. Albonesi; Steven Dropsho

2003-01-01

98

Formal online methods for voltage\\/frequency control in multiple clock domain microprocessors  

Microsoft Academic Search

Multiple Clock Domain (MCD) processors are a promising future alternative to today's fully synchronous designs. Dynamic Voltage and Frequency Scaling (DVFS) in an MCD processor has the extra flexibility to adjust the voltage and frequency in each domain independently. Most existing DVFS approaches are profile-based offline schemes which are mainly suitable for applications whose execution char-acteristics are constrained and repeatable.

Qiang Wu; Philo Juang; Margaret Martonosi; Douglas W. Clark

2004-01-01

99

Energy Aware Dynamic Voltage and Frequency Selection for Real-Time Systems with Energy Harvesting  

E-print Network

Energy Aware Dynamic Voltage and Frequency Selection for Real-Time Systems with Energy Harvesting}@binghamton.edu Abstract In this paper, an energy aware dynamic voltage and frequency selection (EA-DVFS) algorithm energy and the harvested energy in a future duration. Specifically, if the system has sufficient energy

Qiu, Qinru

100

Development of a high frequency and high-voltage pulse transformer for a TWT HVPS  

Microsoft Academic Search

A pulse transformer for a high frequency and high voltage operation had been designed, fabricated, and tested. The high frequency operation of the pulse transformer increases power density. Therefore, it is possible to reduce power supply volume. To produce high voltage output, the transformer should have a high step-up ratio. The step-up ratio is generally limited in pulse transformers due

S. C. KimS; S. H. Nam; H. M. Keon; D. S. Park

2003-01-01

101

On the Use of a Relaxation Oscillator as a Characterized Voltage-to-Frequency Converter  

Microsoft Academic Search

This paper considers the circuit synthesis of a particular type of voltage-to-frequency converter with a predetermined, but arbitrary, voltage-to-frequency characteristic. The basis of this converter is a relaxation oscillator consisting of a linear energy storage network, a combined signal and bias voltage source which provides power to the oscillator, and a single four-layer diode or similar relaxation switch. The paper

E. Bristol

1963-01-01

102

All Silicon Marx-bank Topology for High-voltage, High-frequency Rectangular Pulses  

Microsoft Academic Search

This paper discusses the operation of a fully integrated solid-state Marx generator circuit, which has been developed for high-frequency (kHz), high-voltage (kV) applications needing rectangular pulses. The conventional Marx generator, used for high-voltage pulsed applications, uses inductors, or resistors, to supply the charging capacitors voltage, which has the disadvantages of size, power loss and frequency limitation. The proposed circuit takes

L. M. Redondo; J. F. Silva; P. Tavares; E. Margato

2005-01-01

103

Very-high-frequency low-voltage power delivery  

E-print Network

Power conversion for the myriad low-voltage electronic circuits in use today, including portable electronic devices, digital electronics, sensors and communication circuits, is becoming increasingly challenging due to the ...

Li, Wei, Ph. D. Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science

2013-01-01

104

Position and Speed Estimation of Maglev Train Based on High-frequency Voltage Signal Injection Method  

Microsoft Academic Search

In this paper high-frequency voltage signal injection method was applied based on the machine-saliencies of linear synchronous motor used by maglev train. Three-phase symmetrical high-frequency voltage signals was added to the system before SVPWM regulator, which produced high-frequency current signals containing positive component and negative component. The negative current component included position and velocity signals of the mover of the

Guirong Wang; Hong Xu; Wei Wei

2007-01-01

105

Single and joint actions of noise and sinusoidal whole body vibration on TTS2 values and low frequency upright posture sway in men.  

PubMed

In the present study the changes in the TTS2 values and body upright posture sway were examined after exposure of subjects (n = 10) to stable broadband (white) noise (90 dB) alone, to sinusoidal vibration alone [directed vertically at the whole body (Z axis)], and to simultaneous exposure combinations of noise and vibrations of the same type. The frequency of the vibration was 5 Hz, but its acceleration was either 2.12 or 2.44 m/s2. There were six exposure combinations, and subsequently 60 tests were carried out in an exposure chamber. One test consisted of a control period of 30 min, of three consecutive exposure periods of 16 min each and of a recovery period of 15 min. After the three exposure combinations which included noise, half of the subjects were exposed to vibration during the recovery period. Apart from indicating an increase in the temporary hearing threshold, the results showed that simultaneous exposure to noise and vibration increases the instability of the body upright posture. The TTS2 values at the 4 and 6 kHz frequencies increased considerably more rapidly when the subjects were exposed simultaneously to noise and vibration than when exposed to noise alone. Without exception, the TTS2 values increased most during the first exposure period. It was noteworthy that exposure to vibration during the recovery period accelerated the recursion of the TTS2 values, especially in cases where the subjects had been exposed to noise alone. The variance of the body sway amplitudes and the standard deviation increased within the frequency range 0.063-2.000 Hz owing to noise alone and simultaneous noise and vibration. In the directions X and Y, within the frequency ranges 0.063-0.100 Hz and 0.100-0.600 Hz, the means of the maximum amplitudes of body sway increased especially in connection with those tests in which the subjects had been simultaneously exposed to noise and vibration. PMID:6724699

Manninen, O; Ekblom, A

1984-01-01

106

Dynamic Voltage and Frequency Scaling for Scientific Applications  

Microsoft Academic Search

This paper discusses the benefit of dynamic voltage and fre- quency scaling for scientific applications under different optimization lev- els. The reported experiments show the tradeoffs between optimizations for performance in terms of execution time, power dissipation, and overall energy consumption.

Chung-hsing Hsu; Ulrich Kremer

2001-01-01

107

Fig. 1. Circuit diagram of LCC resonant inverter, HV-transformer and symmetrical three-stage voltage multiplier rectifier [9] (Each of the shown diode consists of 10 single diodes connected in series with parallel snubbers and capacitors).  

E-print Network

with a Capacitive Load Applied in Very Low Frequency High Voltage Test System Manli Hu, Norbert Fröhleke, Joachim, froehleke, boecker}@lea.upb.de Abstract ­ Very low frequency (VLF) high voltage (HV) sinusoidal waveforms, the voltage conversion characteristics enable wide operation ranges in terms of output voltage, power and load

Paderborn, Universität

108

46 CFR 111.01-17 - Voltage and frequency variations.  

Code of Federal Regulations, 2012 CFR

...DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS General...frequency variations. Unless otherwise stated, electrical equipment must function at variations of at...

2012-10-01

109

46 CFR 111.01-17 - Voltage and frequency variations.  

Code of Federal Regulations, 2010 CFR

...DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS General...frequency variations. Unless otherwise stated, electrical equipment must function at variations of at...

2010-10-01

110

46 CFR 111.01-17 - Voltage and frequency variations.  

Code of Federal Regulations, 2011 CFR

...DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS General...frequency variations. Unless otherwise stated, electrical equipment must function at variations of at...

2011-10-01

111

Low frequency magnetic emissions and resulting induced voltages in a pacemaker by iPod portable music players  

PubMed Central

Background Recently, malfunctioning of a cardiac pacemaker electromagnetic, caused by electromagnetic interference (EMI) by fields emitted by personal portable music players was highly publicized around the world. A clinical study of one patient was performed and two types of interference were observed when the clinicians placed a pacemaker programming head and an iPod were placed adjacent to the patient's implanted pacemaker. The authors concluded that "Warning labels may be needed to avoid close contact between pacemakers and iPods". We performed an in-vitro study to evaluate these claims of EMI and present our findings of no-effects" in this paper. Methods We performed in-vitro evaluations of the low frequency magnetic field emissions from various models of the Apple Inc. iPod music player. We measured magnetic field emissions with a 3-coil sensor (diameter of 3.5 cm) placed within 1 cm of the surface of the player. Highly localized fields were observed (only existing in a one square cm area). We also measured the voltages induced inside an 'instrumented-can' pacemaker with two standard unipolar leads. Each iPod was placed in the air, 2.7 cm above the pacemaker case. The pacemaker case and leads were placed in a saline filled torso simulator per pacemaker electromagnetic compatibility standard ANSI/AAMI PC69:2000. Voltages inside the can were measured. Results Emissions were strongest (? 0.2 ?T pp) near a few localized points on the cases of the two iPods with hard drives. Emissions consisted of 100 kHz sinusoidal signal with lower frequency (20 msec wide) pulsed amplitude modulation. Voltages induced in the iPods were below the noise level of our instruments (0.5 mV pp in the 0 1 kHz band or 2 mV pp in the 0 5 MHz bandwidth. Conclusion Our measurements of the magnitude and the spatial distribution of low frequency magnetic flux density emissions by 4 different models of iPod portable music players. Levels of less than 0.2 ?T exist very close (1 cm) from the case. The measured voltages induced inside an 'instrumented-can' pacemaker were below the noise level of our instruments. Based on the observations of our in-vitro study we conclude that no interference effects can occur in pacemakers exposed to the iPod devices we tested. PMID:18241327

Bassen, Howard

2008-01-01

112

Effect of supply voltage frequency on testing of insulation system  

Microsoft Academic Search

This paper deals with the effect of supply frequency on partial discharge phenomena. Results of measurements performed on artificial and practical test objects are compared with computer simulations based on physical models. This comparative analysis points out and explains the differences in partial discharge phenomena observed in tests performed at different frequencies (from 0.1 to 300 Hz). The consequences associated

Andrea Cavallini; Gian Carlo Montanari

2006-01-01

113

High power density, high frequency, and high voltage pulse transformer  

Microsoft Academic Search

Summary form only given, as follows. In designing a compact and high efficiency TWT microwave amplifier, the role of a high power density DC power supply is very important. In order to reduce volume of the power supply, it is necessary to increase switching frequency of the power supply. The high operation frequency mainly reduces transformer volume in the power

S. C. Kim; S. H. Nam; D. T. Kim

2001-01-01

114

High power density, high frequency, and high voltage pulse transformer  

Microsoft Academic Search

In designing a compact and high efficiency TWT microwave amplifier, the role of a high power density DC power supply is very important. In order to reduce volume of the power supply, it is necessary to increase switching frequency of the power supply. The high operation frequency mainly reduces transformer volume in the power supply. However, a step-up ratio of

S. C. Kim; S. H. Nam; S. H. Kim; D. T. Kim; S. H. Jeong

2001-01-01

115

A short report on voltage-to-frequency conversion for HISTRAP RF system tuning control loops  

SciTech Connect

One of the requirements of the HISTRAP RF accelerating system is that the frequency of the accelerating voltage for the cavity must keep in step with the change in the magnetic field. As the energy of the particle increases, the magnetic field is increased to keep the radius of the particle orbit constant. At the same time, the frequency of the electric field must be changed to insure that it is synchronized with the angular movement of the particle. So we need to generate the frequency of the accelerating voltage in relation to the magnetic field. The frequency generation can be accomplished in two stages. The first stage of frequency generation consists of measuring the magnetic field in terms of voltage which is already developed. The second stage is to convert this voltage into frequency. Final frequency precision can be achieved by deriving a frequency-correcting signal from the beam position. This project is concerned with generating the frequency from the analog voltage. The speed of response required will place very stringent requirements on both hardware and software. Technology is available to carry out this task. A hardware configuration has been established and software has been developed. In the following section, we describe the implementation strategy, the hardware configuration, and the desired specifications. Next, we present the software developed, results obtained, along with capabilities and limitations of the system. Finally, we suggest alternate solutions to overcome some of the limitations toward meeting our goal. In the appendices, we include program listings.

Hasanul Basher, A.M.

1991-09-01

116

Neural network theory based voltage and frequency controller for standalone wind energy conversion system  

Microsoft Academic Search

In this paper, a solid state voltage and frequency (VF) controller is proposed for a standalone wind energy conversion system (WECS) employing a permanent magnet synchronous generator (PMSG). The proposed VF controller consists of IGBTs (insulated gate bipolar transistors) based three-leg voltage source converter (VSC) with a battery energy storage system (BESS) at its dc link. The Adaline (adaptive linear

V. Sheeja; P. Jayaprakash; Bhim Singh; R. Uma

2010-01-01

117

Voltage and frequency control of inverter based weak LV network microgrid  

Microsoft Academic Search

In this paper voltage and frequency control of islanded microgrid after intentional and unintentional switching events are investigated. The weak low voltage (LV) network based microgrid consists of two inverter based distributed generation (DG) units. One unit is a storage (battery) unit and the other is a photovoltaic (PV) cell. In this case the battery inverter with rapid response is

H. Laaksonen; P. Saari; R. Komulainen

2005-01-01

118

Battery Based Voltage and Frequency Controller for Parallel Operated Isolated Asynchronous Generators  

Microsoft Academic Search

This paper deals with a battery energy storage system (BESS) based voltage and frequency (VF) controller for parallel operated isolated asynchronous generators (IAGs) driven by uncontrolled pico hydro turbines used in constant power applications. The individual AC capacitor banks are used to generate the rated voltage at no load while additional demand of reactive power for the load and generators

Bhim Singh; Gaurav Kasal; Ambrish Chandra; Kamal-Al-Haddad

2007-01-01

119

Elastic DVS Management in Processors With Discrete Voltage\\/Frequency Modes  

Microsoft Academic Search

Applying classical dynamic voltage scaling (DVS) techniques to real-time systems running on processors with dis- crete voltage\\/frequency modes causes a waste of computational resources. In fact, whenever the ideal speed level computed by the DVS algorithm is not available in the system, to guarantee the feasibility of the task set, the processor speed must be set to the nearest level

Mauro Marinoni; Giorgio C. Buttazzo

2007-01-01

120

Current mode integrators and their applications in low-voltage high frequency CMOS signal processing  

E-print Network

Low voltage CMOS fully differential integrators for high frequency continuous-time filters using current-mode techniques are presented.. Current mode techniques are employed to avoid the use of the floating differential pair, in order to achieve...

Smith, Sterling Lane

2012-06-07

121

Application of the zero method and frequency spectrum conversion for investigating complex periodic voltages  

Microsoft Academic Search

Changes in the frequency spectrum width of the voltage ux(t), which are due to variations in a time scale, can be used in many cases, for instance, in measuring an infrasonic spectrum Ux(t) by means of ordinary spectral analyzers at frequencies of 20 Hz and higher. Below an example is provided of recording the spectrum of the voltage Ux(t )

E. L. Kantor

1970-01-01

122

Singleloop vs two-loop voltage and frequency control of isolated SEIG based RECS  

Microsoft Academic Search

Present investigation deals with the comparison of performance of a Generalized Impedance Controller (GIC) based 3-phase self excited induction generator (SEIG) terminal voltage and frequency regulator, having single and two-loop control, in an isolated wind\\/microhydro type renewable energy conversion system (RECS). Where, GIC is a PWM voltage source converter with dc-bus battery, having controlled four-quadrant equivalent impedance. Amplitude and frequency

J. K. Chatterjee; Priyesh J. Chauhan

2011-01-01

123

Dynamic voltage and frequency management for a low-power embedded microprocessor  

Microsoft Academic Search

A dynamic voltage and frequency management scheme that autonomously controls the clock frequency (8 to 123 MHz at 0.5 MHz step) and adaptively controls the voltage (0.9 to 1.6 V at 5 mV step) with a leakage power compensation effect is developed for a low-power embedded microprocessor. It achieves 82% power reduction in personal information manager (PIM) application.

Satoshi Akui; Katsunori Seno; Masakatsu Nakai; Tetsumasa Meguro; Takahiro Seki; Tetsuo Kondo; Akihiko Hashiguchi; Hirokazu Kawahara; Kazuo Kumano; Masayuki Shimura

2004-01-01

124

Comparison of three accurate methods to measure AC voltage at low frequencies  

Microsoft Academic Search

Three methods for the determination of the RMS value of AC voltage at low frequencies are compared: the step calibration of a digitally synthesized source, the optimized sampling method, and the AC-DC voltage transfer with a multijunction thermal converter. The three methods agree within 110-6 with an uncertainty of 2.510-8 in the frequency range from 10 to 100 Hz

Marian Kampik; Hctor Laiz; Manfred Klonz

2000-01-01

125

Analysis of dynamic voltage\\/frequency scaling in chip-multiprocessors  

Microsoft Academic Search

Fine-grained dynamic voltage\\/frequency scaling (DVFS) de- monstrates great promise for improving the energy-efficiency of chip-multiprocessors (CMPs), which have emerged as a popular way for designers to exploit growing transistor bud- gets. We examine the tradeoffs involved in the choice of both DVFS control scheme and method by which the pro- cessor is partitioned into voltage\\/frequency islands (VFIs). We simulate real

Sebastian Herbert; Diana Marculescu

2007-01-01

126

Feedback-Based Dynamic Voltage and Frequency Scaling for Memory-Bound Real-Time Applications  

Microsoft Academic Search

Dynamic voltage and frequency scaling is increasingly being used to reduce the energy requirements of embed- ded and real-time applications by exploiting idle CPU re- sources, while still maintaining all application's real-time characteristics. Accurate predictions of task run-times a re key to computing the frequencies and voltages that en- sure that all tasks' real-time constraints are met. Past wor k

Christian Poellabauer; Leo Singleton; Karsten Schwan

2005-01-01

127

Voltage and frequency control of self-excited slip-ring induction generators  

Microsoft Academic Search

By varying the effective rotor resistance of a self-excited slip-ring induction generator (SESRIG), the magnitude and frequency of the output voltage can be controlled over a wide speed range. A steady-state analysis based on a normalized equivalent circuit enables the control characteristics to be deduced. For a given stator load impedance, both the frequency and the voltage can be maintained

T. F. Chan; K. A. Nigim; L. L. Lai

2004-01-01

128

Voltage and Frequency Control With Adaptive Reaction Time in Multiple-Clock-Domain Processors  

Microsoft Academic Search

Dynamic voltage and frequency scaling (DVFS) is a widely-used method for energy-efcient computing. In this paper, we present a new intra-task online DVFS scheme for multiple clock domain (MCD) processors. Most existing online DVFS schemes for MCD processors use a x ed time interval between possible voltage \\/frequency changes. The downside to this approach is that the interval boundaries are

Qiang Wu; Philo Juang; Margaret Martonosi; Douglas W. Clark

2005-01-01

129

Frame-based dynamic voltage and frequency scaling for a MPEG decoder  

Microsoft Academic Search

This paper describes a dynamic voltage and frequency scaling (DVFS) technique for MPEG decoding to reduce the energy consumption while maintaining a quality of servic(QoS) constraint. The computational workload for an incoming frame is predicted using a frame-based history so that the processor voltage and frequency can be scaled to provide the exact amount of computing power needed to decode

Kihwan Choi; Karthik Dantu; Wei-Chung Cheng; Massoud Pedram

2002-01-01

130

Induction-generator-based system providing regulated voltage with constant frequency  

Microsoft Academic Search

The electrical characteristics of an isolated induction-generator-based system are improved through the association with a voltage-source pulsewidth modulation (PWM) inverter. The electronic converter allows the achievement of a better system behavior in many aspects: voltage regulation, frequency stabilization, and reactive power compensation. The system operation strategy consists of maintaining constant synchronous frequency at the induction generator via an association with

Enes Gonalves Marra; Jos Antenor Pomilio

2000-01-01

131

A photoelectric relay for measuring voltages of low frequency  

Microsoft Academic Search

SummaryA device is described, which can be used for amplifying and measuring the a.c. output of slow responding detectors (e.g. bolometers),\\u000a receiving signals of constant but low frequency (~1 Hz). This device, based on frequency conversion, which in principle is\\u000a insensitive to drift-effects, consists of a primary galvanometer, a rotating disk, chopping the lightbeam reflected by the\\u000a moving mirror of

J. M. W. Milatz; H. J. J. van Boort; J. van Laar; C. T. J. Alkemade

1955-01-01

132

A photoelectric relay for measuring voltages of low frequency  

Microsoft Academic Search

SummaryA device is described, which can be used for amplifying and measuring the a.c. output of slow responding detectors (e.g. bolometers),\\u000a receiving signals of constant but low frequency (?1 Hz). This device, based on frequency conversion, which in principle is\\u000a insensitive to drift-effects, consists of a primary galvanometer, a rotating disk, chopping the lightbeam reflected by the\\u000a moving mirror of

J. M. W. Milatz; H. J. J. van Boort; J. van Laar; C. T. J. Alkemade

1953-01-01

133

Procrastinating Voltage Scheduling with Discrete Frequency Sets Zhijian Lu, Yan Zhang, Mircea Stan, John Lach, Kevin Skadron  

E-print Network

Procrastinating Voltage Scheduling with Discrete Frequency Sets Zhijian Lu, Yan Zhang, Mircea Stan-task voltage/frequency scheduling for single tasks in practical real-time systems using statistical workload in on these prior works. First they assume voltage/frequency can be continu- ously scaled, and have to round

Skadron, Kevin

134

Control Design for a Very Low-Frequency High-Voltage Test System Zhiyu Cao, Norbert Frhleke, Joachim Bcker  

E-print Network

Control Design for a Very Low-Frequency High-Voltage Test System Zhiyu Cao, Norbert Fröhleke and energy consumption of very low-frequency (VLF) high-voltage test systems (HVTS) versus HVTS of 50 Hz for a Very Low-Frequency High-Voltage Test System CAO Zhiyu EPE 2009 - Barcelona ISBN: 9789075815009 P.1 #12

Paderborn, Universität

135

Theory study on a photonic-assisted radio frequency phase shifter with direct current voltage control  

NASA Astrophysics Data System (ADS)

A photonic-assisted radio frequency phase shifter with direct current voltage control is proposed using a polymer-based integrated Mach—Zehnder modulator. A closed-form expression of radio frequency (RF) signal power and phase is given. Theoretical calculation reveals that by carefully setting the bias voltages, RF signal power variation lower than 1-dB and phase accuracy less than 3° can be achieved and are not degraded by perturbation of modulation index once the bias voltage drift is kept within −3% ~ 3%.

Li, Jing; Ning, Ti-Gang; Pei, Li; Jian, Wei; You, Hai-Dong; Wen, Xiao-Dong; Chen, Hong-Yao; Zhang, Chan; Zheng, Jing-Jing

2014-10-01

136

Low-frequency switching voltage regulators for terrestrial photovoltaic systems  

NASA Technical Reports Server (NTRS)

The photovoltaic technology project and the stand alone applications project are discussed. Two types of low frequency switching type regulators were investigated. The design, operating characteristics and field application of these regulators is described. The regulators are small in size, low in cost, very low in power dissipation, reliable and allow considerable flexibility in system design.

Delombard, R.

1984-01-01

137

Variable speed constant frequency constant voltage alternator. Annual report  

SciTech Connect

A test alternator is operated with digital control of its output frequency for variable shaft speed. The machine is a two-pole alternator with power removed through slip rings. The output frequency of the alternator is controlled by rotating the field by stepping through sixteen coils around the rotor. Usually four coils are active at one time. The rotating field in the stationary coils of the stator is controlled by microcircuits. The control circuits are constructed with available low-cost, low-power integrated circuits (ICs). The test results from the first test alternator indicate the feasibility of using this type of alternator to convert available wind power directly to usable 60 hertz power.

Grannemann, W.W.; Yang, C.E.; Seo, P.H.

1980-07-01

138

Microcontroller Based Three-phase Voltage Source Inverter for Alternative Energy Source  

Microsoft Academic Search

This paper presents a high frequency transformer isolated, micro-controller based, three-phase, ac-to-dc voltage source inverter (VSI) for ac motor drives and uninterruptible power supply applications. The proposed converter produces a 3-phase sinusoidal ac output voltage from alternative energy sources (converted to a 12 V dc voltage source) while output voltage magnitude and frequency can both be controlled digitally using a

M. M. A. Rahman; Kurt Hammons; Phillip Beemer; Marcia Isserstedt; Matt Trommater

139

A short report on voltage-to-frequency conversion for HISTRAP RF system tuning control loops  

Microsoft Academic Search

One of the requirements of the HISTRAP RF accelerating system is that the frequency of the accelerating voltage for the cavity must keep in step with the change in the magnetic field. As the energy of the particle increases, the magnetic field is increased to keep the radius of the particle orbit constant. At the same time, the frequency of

Hasanul Basher

1991-01-01

140

A comparator-based switched-capacitor voltage-to-frequency converter  

Microsoft Academic Search

A novel comparator-based switched-capacitor voltage-to-frequency converter is presented. By using the op-amp as the comparator, it can be operated over wide frequency range. Conversion sensitivity is also insensitive to capacitance ratio and parasitic capacitances between each node and ground.

Hiroki Matsumoto; Zheng Tang; Okihiko Ishizuka

1990-01-01

141

Robust controller design for high frequency resonant inverter system with voltage mode control  

Microsoft Academic Search

In this paper, we proposed a robust controller for high frequency resonant inverter. High frequency resonant inverter requires fast dynamic response and tight control of the output voltage. The component tolerance, load and line variation as well as small signal model inaccuracy all impose challenge in the controller design, while as such inverter feed open AC bus with dynamic load

Z. M. Pe; P. K. Jain; P. C. Sen

2004-01-01

142

A NUMERICAL ALGORITHM FOR DIRECT REAL-TIME ESTIMATION OF VOLTAGE PHASOR, FREQUENCY AND ITS RATE OF CHANGE  

Microsoft Academic Search

A new algorithm for direct estimation of voltage phasor, frequency and its rate of change, of a voltage signal distorted by a DC component and contaminated by random noise is presented. The method is based on the non-recursive Least Error Squares Technique (LS Technique). Using digitized samples of voltage at the relay location, the estimation of the voltage signal unknown

VLADIMIR TERZIJA; MILENKO DJURIC

1996-01-01

143

A Novel Technique To Estimate the Voltage-Dependent Capacitance of a Weakly Nonlinear Device At Microwave Frequencies  

E-print Network

significantly. At millimeter wave frequencies, the current-versus-voltage dependency in the dc domain of capacitance versus voltage characteristic can be done with a commercial C-V meter at a frequency below 1 GhzA Novel Technique To Estimate the Voltage-Dependent Capacitance of a Weakly Nonlinear Device

Haddadi, Hamed

144

The coefficient of the voltage induced frequency shift measurement on a quartz tuning fork.  

PubMed

We have measured the coefficient of the voltage induced frequency shift (VIFS) of a 32.768 KHz quartz tuning fork. Three vibration modes were studied: one prong oscillating, two prongs oscillating in the same direction, and two prongs oscillating in opposite directions. They all showed a parabolic dependence of the eigen-frequency shift on the bias voltage applied across the fork, due to the voltage-induced internal stress, which varies as the fork oscillates. The average coefficient of the VIFS effect is as low as several hundred nano-Hz per millivolt, implying that fast-response voltage-controlled oscillators and phase-locked loops with nano-Hz resolution can be built. PMID:25414971

Hou, Yubin; Lu, Qingyou

2014-01-01

145

Analog-to-Digital Conversion Based on a Voltage-to-Frequency Converter  

Microsoft Academic Search

In this paper we discuss a method of analog-to-digital conversion based on a voltage-to-frequency converter (VFC). The basic principle of a VFC circuit is given in order to derive the exact relationship between the characteristics of the output pulse train and the input voltage. We illustrate this theoretical analysis with an example of a simple VFC circuit. The VFC output

J. M. Vandeursen; J. A. Peperstraete

1979-01-01

146

Voltage and Frequency Control of a Stand Alone Brushless Wind Electric Generation Using Generalized Impedance Controller  

Microsoft Academic Search

In this paper, a new strategy for the control of terminal voltage and frequency of a stand-alone self-excited induction generator-(SEIG) based wind generator, working with variable speed and load is proposed. With a generalized impedance controller (GIC) (voltage source pulsewidth-modulated inverter with a dc-link battery), a new strategy to maintain the active and reactive power balance at the SEIG terminals

B. Venkatesa Perumal; Jayanta K. Chatterjee

2008-01-01

147

Voltage sag mitigation for a high frequency multistage power conversion system  

Microsoft Academic Search

A multistage power conversion scheme, capable of providing a regulated power supply despite disturbances in the source voltage or changes in the output load, is proposed. The high frequency power conversion system also provides compensation for acute voltage sags\\/swells and a faster transient response by employing appropriately controlled power electronics converters. Through the utilization of a bidirectional buck-boost DC-DC converter

M. Peterson; B. N. Singh

2008-01-01

148

A Low-power Low-voltage Direct Digital Frequency Synthesizer  

Microsoft Academic Search

A low-power low-voltage direct digital frequency synthesizer is presented in this paper. With the proposed efficient ROM compression method and other ROM reduction techniques, a compression ratio of 236 is achieved. Through low-power techniques at various design levels: low-voltage (2-V) operation, ROM reduction, the proposed parallel architecture, static conventional CMOS gates, and true single phase clocking scheme, an unparalleled power

Shyuan Liao; Liang-Gee Chen

1997-01-01

149

High voltage dielectric frequency response measurements on polyethylene samples during water tree ageing  

Microsoft Academic Search

High voltage dielectric frequency response measurements have been performed on laboratory aged polyethylene samples with special attention for studying non-linear effects during water tree ageing. A measurement set-up for making high voltage and high sensitive measurements on disc shaped samples in the range of 10 pF is presented. Prior to ageing, the samples were vacuum treated and then equipped with

P. Tharning; U. Gafvert

1995-01-01

150

A novel compact repetitive frequency voltage booster based on magnetic switches and Fitch generator.  

PubMed

In this paper, a novel repetitive frequency voltage booster (named repetitive Fitch booster by the authors) based on magnetic switches and Fitch generators is proposed. The principle of operation is to charge capacitors in parallel when magnetic switches (MSs) are unsaturated and reverse voltage polarity of every other capacitor when MSs saturate. With the principle, circuit topology of a 4-stage repetitive Fitch booster (RFB) is presented. Simulation as well as experiment shows its feasibility in boosting voltage and compressing rise-time. In simulation, the input voltage of 100 V is boosted to 372 V, while test stand yields output voltage with frequency of 1 kHz, amplitude of 19 kV with each capacitor charged to about 5.6 kV, and rise-time compression from 7.3 ?s to 700 ns. Meanwhile, calculations show that the 4-stage RFB effectively reduces core volume by about half, from 1093.5 cm(3) to 585.2 cm(3). Furthermore, design rules are proposed so that topologies of RFBs with stages other than four can be conveniently derived. As an example, an 8-stage RFB is proposed and verified with circuit simulation, which shows an output voltage of 759 V with the input voltage of 100 V. PMID:22852688

Ren, Hang; Ding, Weidong; Wu, Jiawei

2012-07-01

151

A novel compact repetitive frequency voltage booster based on magnetic switches and Fitch generator  

NASA Astrophysics Data System (ADS)

In this paper, a novel repetitive frequency voltage booster (named repetitive Fitch booster by the authors) based on magnetic switches and Fitch generators is proposed. The principle of operation is to charge capacitors in parallel when magnetic switches (MSs) are unsaturated and reverse voltage polarity of every other capacitor when MSs saturate. With the principle, circuit topology of a 4-stage repetitive Fitch booster (RFB) is presented. Simulation as well as experiment shows its feasibility in boosting voltage and compressing rise-time. In simulation, the input voltage of 100 V is boosted to 372 V, while test stand yields output voltage with frequency of 1 kHz, amplitude of 19 kV with each capacitor charged to about 5.6 kV, and rise-time compression from 7.3 ?s to 700 ns. Meanwhile, calculations show that the 4-stage RFB effectively reduces core volume by about half, from 1093.5 cm3 to 585.2 cm3. Furthermore, design rules are proposed so that topologies of RFBs with stages other than four can be conveniently derived. As an example, an 8-stage RFB is proposed and verified with circuit simulation, which shows an output voltage of 759 V with the input voltage of 100 V.

Ren, Hang; Ding, Weidong; Wu, Jiawei

2012-07-01

152

Improved frequency/voltage converters for fast quartz crystal microbalance applications.  

PubMed

The monitoring of frequency changes in fast quartz crystal microbalance (QCM) applications is a real challenge in today's instrumentation. In these applications, such as ac electrogravimetry, small frequency shifts, in the order of tens of hertz, around the resonance of the sensor can occur up to a frequency modulation of 1 kHz. These frequency changes have to be monitored very accurately both in magnitude and phase. Phase-locked loop techniques can be used for obtaining a high performance frequency/voltage converter which can provide reliable measurements. Sensitivity higher than 10 mVHz, for a frequency shift resolution of 0.1 Hz, with very low distortion in tracking both the magnitude and phase of the frequency variations around the resonance frequency of the sensor are required specifications. Moreover, the resonance frequency can vary in a broad frequency range from 5 to 10 MHz in typical QCM sensors, which introduces an additional difficulty. A new frequency-voltage conversion system based on a double tuning analog-digital phase-locked loop is proposed. The reported electronic characterization and experimental results obtained with conducting polymers prove its reliability for ac-electrogravimetry measurements and, in general, for fast QCM applications. PMID:18447558

Torres, R; Garca, J V; Arnau, A; Perrot, H; Kim, L To Thi; Gabrielli, C

2008-04-01

153

Improved frequency/voltage converters for fast quartz crystal microbalance applications  

SciTech Connect

The monitoring of frequency changes in fast quartz crystal microbalance (QCM) applications is a real challenge in today's instrumentation. In these applications, such as ac electrogravimetry, small frequency shifts, in the order of tens of hertz, around the resonance of the sensor can occur up to a frequency modulation of 1 kHz. These frequency changes have to be monitored very accurately both in magnitude and phase. Phase-locked loop techniques can be used for obtaining a high performance frequency/voltage converter which can provide reliable measurements. Sensitivity higher than 10 mV/Hz, for a frequency shift resolution of 0.1 Hz, with very low distortion in tracking both the magnitude and phase of the frequency variations around the resonance frequency of the sensor are required specifications. Moreover, the resonance frequency can vary in a broad frequency range from 5 to 10 MHz in typical QCM sensors, which introduces an additional difficulty. A new frequency-voltage conversion system based on a double tuning analog-digital phase-locked loop is proposed. The reported electronic characterization and experimental results obtained with conducting polymers prove its reliability for ac-electrogravimetry measurements and, in general, for fast QCM applications.

Torres, R.; Kim, L. To Thi [GIBEC-Escuela de Ingenieria de Antioquia, Universidad CES, Calle 25, Sur No. 42-73, Envigado (Colombia); Garcia, J. V.; Arnau, A. [Departamento Ingenieria Electronica. ETSI de Telecomunicacion, Universidad Politecnica de Valencia, Camino de Vera s/n, Valencia 46022 (Spain); Perrot, H.; Gabrielli, C. [Universite Pierre et Marie Curie-Paris 6, Laboratoire Interfaces et Systemes Electrochemiques, CNRS, UPR15-LISE, 4 place Jussieu, Paris 75252 (France)

2008-04-15

154

Improved high-voltage, high-frequency square-wave generator  

NASA Technical Reports Server (NTRS)

This paper describes the design and operation of a prototype high-voltage full-floating high-frequency square-wave generator which is an improved version of the generator developed by Bernius and Chutjian (1989). The present design overcomes possible momentary simultaneous ON states in the MOSFET configuration and is less susceptible to deleterious effects caused by the component aging and replacements with nonidentical parts. The circuit performs well over a wide voltage and frequency range, until a limit is imposed by the operating characteristics of the active MOSFET elements. Circuit diagrams are presented.

Bernius, Mark T.; Chutjian, Ara

1990-01-01

155

Sinusoids: Applications and Modeling  

NSDL National Science Digital Library

This demo actively involves students via the software simulations so that the determination of the sinusoidal model has a geometric flavor that complements the algebraic tools stressed in texts. This approach also introduces a modeling aspect since in some situations we may only be able to obtain a "close" approximation to the actual curve or data. Animations and Excel routines are included.

Roberts, Lila F.; Hill, David R.

2004-07-21

156

Design and implementation of DSP-based voltage frequency conversion system  

Microsoft Academic Search

This paper presents a voltage frequency conversion system with Digital Signal Processor (DSP). The digital control is used to achieve the variable frequency control. The topology of the proposed system is two-stage converter, where the first stage is a power factor correction (PFC) circuit and the second stage is a single-phase full-bridge inverter circuit. The PFC can control input AC

Chih-Yuan Chen; Yu-Hsien Lin; Jiann-Fuh Chen; Ray-Lee Lin

2010-01-01

157

A low-voltage mobility-based frequency reference for crystal-less ULP radios  

Microsoft Academic Search

The design of a 100 kHz frequency reference based on the electron mobility in a MOS transistor is presented. The proposed low-voltage low-power circuit requires no off-chip components, making it suitable for Wireless Sensor Networks (WSN) applications. After one-point calibration the spread of its output frequency is less than 1.1% (3sigma) over the temperature range from -22degC to 85degC. Fabricated

Fabio Sebastiano; Lucien Breems; Kofi Makinwa; Salvatore Drago; Domine Leenaerts; Bram Nauta

2008-01-01

158

A Low-Voltage Mobility-Based Frequency Reference for Crystal-Less ULP Radios  

Microsoft Academic Search

The design of a 100 kHz frequency reference based on the electron mobility in a MOS transistor is presented. The proposed low-voltage low-power circuit requires no off-chip components, making it suitable for application in wireless sensor networks (WSN). After a single-point calibration, the spread of its output frequency is less than 1.1% (3sigma) over the temperature range from -22degC to

Fabio Sebastiano; Lucien J. Breems; Kofi A. A. Makinwa; Salvatore Dargo; Domine M. W. Leenaerts; Bram Nauta

2009-01-01

159

High Voltage High Frequency Class-E Converter Suitable for Miniaturization  

Microsoft Academic Search

A 120 V mains-driven class-E converter used as an electronic ballast for a 15 W fluorescent lamp is presented. The key element of the circuit is a cascoded bipolar metal-oxide semiconductor (BiMOS) switch which ensures high-voltage and high-frequency capability. In spite of the high switching frequency of 450 kHz an excellent efficiency of 91 percent could be achieved. Thus miniaturization

Georg Lutteke; Hubert C. Raets

1986-01-01

160

Off-chip latency-driven dynamic voltage and frequency scaling for an MPEG decoding  

Microsoft Academic Search

This paper describes a dynamic voltage and frequency scaling (DVFS) technique for MPEG decoding to reduce the energy consumption using the computational workload decomposition. This technique decomposes the workload for decoding a frame into on-chip and off-chip workloads. The execution time required for the on-chip workload is CPU frequency-dependent, whereas the off-chip workload execution time does not change, regardless of

Kihwan Choi; Ramakrishna Soma; Massoud Pedram

2004-01-01

161

High-Resolution Spherical Quantization of Sinusoidal Parameters  

Microsoft Academic Search

Sinusoidal coding is an often employed technique in low bit-rate audio coding. Therefore, methods for efficient quantization of sinusoidal parameters are of great importance. In this paper, we use high-resolution assumptions to derive analytical expressions for the optimal entropy-constrained unrestricted spherical quantizers for the amplitude, phase, and frequency parameters of the sinusoidal model. This is done both for the case

Pim Korten; Jesper Jensen; Richard Heusdens

2007-01-01

162

Optimizing performance per watt on GPUs in High Performance Computing: temperature, frequency and voltage effects  

E-print Network

The magnitude of the real-time digital signal processing challenge attached to large radio astronomical antenna arrays motivates use of high performance computing (HPC) systems. The need for high power efficiency (performance per watt) at remote observatory sites parallels that in HPC broadly, where efficiency is an emerging critical metric. We investigate how the performance per watt of graphics processing units (GPUs) is affected by temperature, core clock frequency and voltage. Our results highlight how the underlying physical processes that govern transistor operation affect power efficiency. In particular, we show experimentally that GPU power consumption grows non-linearly with both temperature and supply voltage, as predicted by physical transistor models. We show lowering GPU supply voltage and increasing clock frequency while maintaining a low die temperature increases the power efficiency of an NVIDIA K20 GPU by up to 37-48% over default settings when running xGPU, a compute-bound code used in radio...

Price, D C; Barsdell, B R; Babich, R; Greenhill, L J

2014-01-01

163

Utilization of the voltage frequency converter or digital representation and documentation of transient reactor operation  

Microsoft Academic Search

The ease and speed of handling transient data is enhanced by the use of a voltage to frequency converter (VFC). This analogue to digital semiconductor device provides an inexpensive and portable alternative to electro-mechanical recorders and hand entry of data into computer codes. The VFC used at The University of Arizona is a Teledyne Philbrick 4705\\/01. A zero to positive

Doane; Harry J

1986-01-01

164

Understanding Pound-Drever-Hall locking using voltage controlled radio-frequency oscillators: An undergraduate experiment  

E-print Network

Understanding Pound-Drever-Hall locking using voltage controlled radio-frequency oscillators controlled oscillator to a cavity resonance at 800 MHz using the Pound-Drever-Hall method. This technique of microwave oscillators, and adapted to the optical domain by Drever et al.2 In brief, the source

Le Roy, Robert J.

165

Frame-Based Dynamic Voltage and Frequency Scaling for a MPEG Decoder  

E-print Network

frame is predicted using a frame-based history so that the processor voltage and frequency can be scaled and communication devices has been increasing rapidly. Because portable devices are battery-operated, a design objective is to minimize the energy dissipation (and thus maximize the battery service time) without any

Pedram, Massoud

166

Short report on voltage-to-frequency conversion for HISTRAP RF system tuning control loops.  

National Technical Information Service (NTIS)

One of the requirements of the HISTRAP RF accelerating system is that the frequency of the accelerating voltage for the cavity must keep in step with the change in the magnetic field. As the energy of the particle increases, the magnetic field is increase...

A. M. Hasanul Basher

1991-01-01

167

Comparison of switching devices in scalable switch concept for medium voltage medium frequency power conversion  

Microsoft Academic Search

This paper provides a comparison of switch concepts for medium frequency (MF) medium voltage (MV) applications in the lower power range (> 1 kHz). The comparison is based on measurements of actual discrete switches for hard-switched and ZVS forward topologies. It is shown that standard low power IGBTs in a scalable switch can be used to obtain the lowest losses

Jochen Mast; Guntram Scheible; Henry Gueldner

2001-01-01

168

Voltage frequency controller for stand alone WECS employing permanent magnet synchronous generator  

Microsoft Academic Search

In this paper, a battery energy storage system (BESS) based voltage and frequency (VF) controller based on isolated three-leg VSC with a zig-zag transformer is proposed for stand alone power generation using a permanent magnet synchronous generator (PMSG). An isolated distributed generation (DG) system is realised using fixed pitch wind turbine. The proposed stand alone wind energy conversion system (WECS)

Bhim Singh; V. Sheeja; R. Uma; P. Jayaprakash

2009-01-01

169

Voltage and frequency control with neutral current compensation in an isolated wind energy conversion system  

Microsoft Academic Search

This paper presents a voltage and frequency controller with neutral current compensation in an isolated wind energy conversion system employing a capacitor excited asynchronous generator (CEAG). In isolated applications, because of unavailability of the neutral point at the generator terminals, it is difficult to access the neutral wire from the source. In view of this, a transformer integrated with a

G. K. Kasal; B. Singh; A. Chandra; K. Al-Haddad

2008-01-01

170

Energy Aware Dynamic Voltage and Frequency Selection for Real-Time Systems with Energy Harvesting  

Microsoft Academic Search

In this paper, an energy aware dynamic voltage and frequency selection (EA-DVFS) algorithm is proposed. The EA-DVFS algorithm adjusts the processor's behavior depending on the summation of the stored energy and the harvested energy in a future duration. Specifically, if the system has sufficient energy, tasks are executed at full speed; otherwise, the processor slows down task execution to save

Shaobo Liu; Qinru Qiu; Qing Wu

2008-01-01

171

Voltage Standing Wave Ratio Waveguide Components Frequency: 2.6 To 26.5 Ghz.  

National Technical Information Service (NTIS)

The manual describes the measurement procedure for the voltage standing wave ratio (VSWR) of waveguide components in the frequency range of 2.60 to 26.50 GHz as listed in table 1. Appendix A contains a list of components which may be calibrated by this pr...

1965-01-01

172

Optimal efficiency analysis of induction motors fed by variable-voltage and variable-frequency source  

Microsoft Academic Search

The authors discuss the efficiency analysis and experimental data for an induction motor fed by a variable-voltage and variable-frequency (VVVF) source. Nonideal factors (core saturation, source harmonics, and skin effect) affecting the efficiency are included in the analysis to yield practical results from computer simulation. Based on the simulated results, an experimental system, composed of a DC link power converter

SEN CHEN; S.-N. Yeh

1992-01-01

173

New, zero voltage switching, high frequency boost converter topology for power factor correction  

Microsoft Academic Search

This paper introduces a technique for combining zero-voltage-switching with boost converter technology to enable high frequency, high efficiency operation of the converter. The combination creates a new topology which is effective to meet the power factor correction and harmonic reduction requirements of new EMC standards. The unique topology provides limitation of the recovery current of the boost diode and uses

John A Bassett

1995-01-01

174

Failure analysis of 6T SRAM on low-voltage and high-frequency operation  

Microsoft Academic Search

Careful analysis of SRAM bit failure at high-frequency operation has been described. Using the nanoprober technique, MOS characteristics of failure bit in actual memory cells had been measured directly. It was confirmed that the drain current of a PMOS was about one order in magnitude smaller and the threshold voltage was about 1 V higher than that for normal bits.

Shuji Ikeda; Yasuko Yoshida; Koichiro Ishibashi; Yasuhiro Mitsui

2003-01-01

175

A novel electrode power profiler for dimmable ballasts using DC link voltage and switching frequency controls  

Microsoft Academic Search

A novel electrode power profiler for dimmable ballasts using series-resonant parallel-loaded inverter is presented. Dimming of the fluorescent lamp is primarily based on reducing the dc link voltage. Variations of the electrode power (due to the decrease in the lamp current) during dimming is compensated by changing the switching frequency of the inverter, so that the resonant tank circuit current

Stephen T. S. Lee; Henry Shu-Hung Chung; S. Y. R. Hui

2004-01-01

176

Fault Detection on Multicell Converter Based on Output Voltage Frequency Analysis  

Microsoft Academic Search

Multilevel converters use a large amount of semiconductors, allowing the reconfigurate of the converter to work even on internal fault condition. This paper presents a method to detect faulty cells in a cascaded multicell converter requiring just one voltage measurement per output phase. The method is based on high-frequency harmonic analysis, using a dynamic prediction of their behavior, avoiding erroneous

Pablo Lezana; Ricardo Aguilera; Jos Rodrguez

2009-01-01

177

A Three-Phase Voltage and Frequency Droop Control Scheme for Parallel Inverters  

Microsoft Academic Search

As the number of grid-connected distributed generation units continues to increase, it becomes more difficult to exclude these units from participating in the control of the grid voltage magnitude and frequency. Another future development might be the division of the grid in smaller microgrids, able to operate either connected to the utility grid or in island mode. In this paper

T. Loix; K. De Brabandere; J. Driesen; R. Belmans

2007-01-01

178

Voltage-frequency control of a self-excited induction generator  

Microsoft Academic Search

A new strategy for controlling voltage and frequency of a self excited induction generator (SEIG) is presented. The SEIG operates in the linear region of the core magnetizing curve, so that efficiency and performance are upgraded. An external excitation circuit, comprising permanently connected capacitors and electronically switched inductances is used. The external circuit allows to compensate for the generator reactive

E. Suarez; Gustavo Bortolotto

1999-01-01

179

Hepatic sinusoidal ectasia.  

PubMed

Oral contraceptive-associated sinusoidal ectasia is a rare lesion of unknown pathogenesis. We describe the case of a 31-year-old woman who had used oral contraceptives for 10 years and was found to have abnormal liver function tests on "routine" examination. A single 9 x 5 x 4 cm hypervascular lesion was demonstrated radiographically. The hepatic immuno-diacetic acid and liver-spleen scans were normal. One subcapsular lesion was identified in the resected right hepatic lobe; it was characterized by focal marked dilatation of the sinusoidal spaces associated with rare hepatocyte necrosis and early intrasinusoidal fibrosis. The subcapsular location and the vascular nature of this wedge-shaped lesion suggest it may represent the telangiectatic precursor of a centrally scarred focal nodular hyperplasia. PMID:1644440

Oligny, L L; Lough, J

1992-08-01

180

Special modulator for high frequency, low-voltage plasma immersion ion implantation  

NASA Astrophysics Data System (ADS)

Plasma immersion ion implantation is a burgeoning surface modification technique and not limited by the line-of-sight restriction plaguing conventional beam-line ion implantation. It is therefore an excellent technique to treat interior surfaces as well as components of a complex shape. To enhance the implant uniformity and increase the thickness of the modified layer, we are using a high frequency, low-voltage process to achieve high temperature and dose rate to increase the thickness of the modified layer. The low voltage conditions also lead to a thinner sheath more favorable to conformal implantation. In this article, we will describe our special modulator consisting of a single ended forward converter with a step-up transformer. The modulator is designed to operate from 5 to 35 kHz and the output voltage is adjustable to an upper ceiling of 5000 V that is deliberately chosen to be our voltage limit for the present experiments. We will also present experimental data on SS304 stainless steel materials elucidating the advantages of our modulator and high frequency, low-voltage experimental protocols.

Tian, Xiubo; Wang, Xiaofeng; Tang, Baoyin; Chu, Paul K.; Ko, Ping K.; Cheng, Yiu-Chung

1999-03-01

181

New frequency/voltage converters for ac-electrogravimetric measurements based on fast quartz crystal microbalance.  

PubMed

A better understanding of the mechanisms located at the solid/electrolyte interface is becoming essential to the development of new applications in the electrochemical fields. The fast quartz crystal microbalance is an attractive and powerful gravimetric sensor which can be used in the dynamic regime to determine a mass/potential transfer function. The principle is equivalent to classical electrochemical impedance measurements; the only difference is the determination of mass changes given by the quartz crystal microbalance rather than current changes following sine wave modulations of the applied potential. This function appears very well adapted to characterize ionic exchanges at the electrochemical interface. Frequency/voltage converters are the key devices in translating the microbalance frequency response in terms of a continuous voltage change. The latter allows the transfer function to be obtained via a frequency response analyzer. Different converters were tested in this work in order to improve the performances of the experimental setup. PMID:17672777

Gabrielli, C; Perrot, H; Rose, D; Rubin, A; Toqu, J P; Pham, M C; Piro, B

2007-07-01

182

On the application of radio frequency voltages to ion traps via helical resonators  

E-print Network

Ions confined using a Paul trap require a stable, high voltage and low noise radio frequency (RF) potential. We present a guide for the design and construction of a helical coil resonator for a desired frequency that maximises the quality factor for a set of experimental constraints. We provide an in-depth analysis of the system formed from a shielded helical coil and an ion trap by treating the system as a lumped element model. This allows us to predict the resonant frequency and quality factor in terms of the physical parameters of the resonator and the properties of the ion trap. We also compare theoretical predictions with experimental data for different resonators, and predict the voltage applied to the ion trap as a function of the Q-factor, input power and the properties of the resonant circuit.

J. D. Siverns; L. R. Simkins; S. Weidt; W. K. Hensinger

2011-06-24

183

Low noise frequency synthesizer with self-calibrated voltage controlled oscillator and accurate AFC algorithm  

NASA Astrophysics Data System (ADS)

A low noise phase locked loop (PLL) frequency synthesizer implemented in 65 nm CMOS technology is introduced. A VCO noise reduction method suited for short channel design is proposed to minimize PLL output phase noise. A self-calibrated voltage controlled oscillator is proposed in cooperation with the automatic frequency calibration circuit, whose accurate binary search algorithm helps reduce the VCO tuning curve coverage, which reduces the VCO noise contribution at PLL output phase noise. A low noise, charge pump is also introduced to extend the tuning voltage range of the proposed VCO, which further reduces its phase noise contribution. The frequency synthesizer generates 9.7511.5 GHz high frequency wide band local oscillator (LO) carriers. Tested 11.5 GHz LO bears a phase noise of?104 dBc/Hz at 1 MHz frequency offset. The total power dissipation of the proposed frequency synthesizer is 48 mW. The area of the proposed frequency synthesizer is 0.3 mm2, including bias circuits and buffers.

Peng, Qin; Jinbo, Li; Jian, Kang; Xiaoyong, Li; Jianjun, Zhou

2014-09-01

184

Wave amplification by a relativistic electron beam in a planar electrostatic system with sinusoidal-ripple boundary  

SciTech Connect

Primary study is devoted to the amplification mechanism of electromagnetic fast wave by a relativistic electron beam in a planar electrostatic system, where the superplate of two parallel metallic plates is corrugated with sinusoidal ripples and connected to a negative voltage, while the subplate is smooth and grounded. In the system the electrostatic field governs the electrons to move along approximately sinusoidal trajectories and pumps the kinetic energy of electrons to the wave. Under exclusion of the space-charge wave effect and the Smith-Purcell effect, the fast wave gets relativistic Doppler upshift frequency and gain by extracting energy from a sheet electron beam, which is very similar to that in a free-electron laser pumped by a magnetostatic wiggler. Formulas derived and numerical analysis indicate that the amplification mechanism of wave pumped by the planar electrostatic system with sinusoidal ripples is favorable for a mildly relativistic electron beam to generate terahertz wave.

Zhang Shichang [Institute of Photoelectronics, Campus Mail Box 50, Southwest Jiaotong University, Chengdu SC610031 (China)

2009-09-15

185

>300GHz Fixed-Frequency and Voltage-Controlled Fundamental Oscillators in an InP DHBT Process  

E-print Network

>300GHz Fixed-Frequency and Voltage-Controlled Fundamental Oscillators in an InP DHBT Process, 93106, USA Abstract -- We report fundamental fixed-frequency and voltage-controlled oscillators operating at >300GHz fabricated in a 256nm InP DHBT technology. Oscillator designs are based

Rodwell, Mark J. W.

186

Challenges and opportunities for multi-functional oxide thin films for voltage tunable radio frequency/microwave components  

E-print Network

and opportunities for multi-functional oxide thin films for voltage tunable radio frequency/microwave componentsChallenges and opportunities for multi-functional oxide thin films for voltage tunable radio frequency/microwave components Guru Subramanyam, M. W. Cole, Nian X. Sun, Thottam S. Kalkur, Nick M

Chen, Long-Qing

187

An All-MOS High-Linearity Voltage-to-Frequency Converter Chip With 520kHz\\/V Sensitivity  

Microsoft Academic Search

An all-MOS linear voltage-to-frequency converter (VFC) chip with 520-kHz\\/V sensitivity is presented in this paper. This circuit converts an input voltage into frequency by charging and discharging a capacitor. An all-MOS voltage window comparator (VWC) with reduced propagation delay is designed to improve the linearity of traditional VFCs. The propagation delay of the VWC is discussed to resolve the tradeoff

Chua-Chin Wang; Tzung-Je Lee; Chi-Chen Li; Ron Hu

2006-01-01

188

An All-MOS High Linearity Voltage-to-Frequency Converter Chip with 520 KHz\\/V Sensitivity  

Microsoft Academic Search

An all-MOS linear voltage-to-frequency converter (VFC) chip with 520 KHz\\/V sensitivity is presented in this paper. This circuit converts an input voltage into frequency by charg- ing and discharging a capacitor. An all-MOS voltage window comparator (VWC) with reduced propagation delay is designed to improve the linearity of traditional VFCs. The propagation delay of the VWC is discussed to resolve

Chua-chin Wang; Tzung-je Lee; Chih-chen Li; Ron Hu

2006-01-01

189

A high-frequency high-efficiency three-level LCC converter for high-voltage charging applications  

Microsoft Academic Search

For high-voltage charging applications, this paper introduces a variable-frequency zero-voltage-switching three-level LCC resonant converter, which is able to utilize the parasitic components of the high-turns-ratio transformer. By applying the three-level structure in the primary side, low-voltage MOSFETs can be used to minimize the conduction loss. Therefore, the switching frequency can be increased to shrink the size of passive components. In

Yang Qiu; Bing Lu; Bo Yang; Dianbo Fu; Fred C. Lee; F. Canales; R. Gean; W. C. Tipton

2004-01-01

190

Non-sinusoidality of a signal as a source of error in instruments measuring root-mean-square value  

Microsoft Academic Search

This paper presents additional errors resulting from the finite frequency band transferred by converters of true root-mean-square value. These errors are revealed in a specific way on converting non-sinusoidal signals into dc voltage. Approximated expressions, which make it possible to calculate quickly the uncertainties for some typical signal waveforms, are given, enabling instrument users to evaluate the accuracy of the

E. Nowaczyk

1998-01-01

191

A Simulation of MEMS Voltage-Frequency Convertor with Electronic Circuit Simulator  

NASA Astrophysics Data System (ADS)

An electrostatic micro actuator with an electrical contact between the electrodes is known to show a limit-cycle behavior due to the combination of electrostatic pull-in and release. We newly used an electrical circuit simulator to make an equivalent circuit model to reproduce the limit-cycle by multi-physics simulation. This simulation results were found to explain the experimenntally observed behavior of the developedMEMS voltage to frequency convertor (VFC).

Mita, Makoto; Maruyama, Satoshi; Ataka, Manabu; Toshiyoshi, Hiroshi

192

Design and Management of Voltage-Frequency Island Partitioned Networks-on-Chip  

Microsoft Academic Search

The design of many core Systems-on-Chip (SoCs) has become increasingly challenging due to high levels of integration, excessive energy consumption and clock distribution problems. To deal with these issues, we consider Network-on-Chip (NoC) archi- tectures partitioned into several voltage-frequency islands (VFIs) and propose a design methodology for run-time energy manage- ment. The proposed approach minimizes the energy consumption subject to

mit Y. Ogras; Radu Marculescu; Diana Marculescu; Eun Gu Jung

2009-01-01

193

Design considerations of high voltage and high frequency three phase transformer for Solid State Transformer application  

Microsoft Academic Search

The three-phase Solid State Transformer (SST) is one of the key elements in the Future Renewable Electric Energy Delivery and Management (FREEDM) System. The SST consists of an input rectifier, Dual Active Bridge (DAB) bidirectional dc-dc converter and followed by an inverter for ac voltage output. The DAB converter is a bidirectional dc-dc converter using high frequency transformers to step

Chun-kit Leung; S. Dutta; Seunghun Baek; Subhashish Bhattacharya

2010-01-01

194

Energy efficient ECS powered by a variable voltage\\/variable frequency power system  

Microsoft Academic Search

The invention is an ECS system designed to utilize an induction motor and a cabin compressor for providing pressurized air that serves as a source of energy for heating, cooling, pressurizing and other air needs of modern aircraft. An aircraft engine driven generator, preferably a permanent-magnet generator (of the samarium-cobalt, SmCo, type), furnishes variable-voltage\\/variable frequency, VV\\/VF, power to the motor.

Cronin

1984-01-01

195

Energy efficient ECS powered by a variable voltage\\/variable frequency power system  

Microsoft Academic Search

The invention is an ECS system designed to utilize an induction motor and a cabin compressor for providing pressurized air that serves as a source of energy for heating, cooling, pressurizing and other air needs of modern aircraft. An aircraft engine driven generator, preferably a permanent-magnet generator (of the samarium-cobalt, SmCo, type), furnishes variable-voltage\\/variable frequency, VV\\/VF, power to the motor.

Cronin

1985-01-01

196

Improvement in microscope photometry by voltage to frequency conversion: analogue measurement and digital processing.  

PubMed

A system for digital measurement of microscope photometric signals, based on Voltage to Frequency Conversion (VFC) and suitable for automatic data processing, has been devised. Advantages and disadvantages are illustrated with special emphasis on the comparison between photocurrent measuring and photon counting techniques. A statistical analysis of the results allows the calibration of VFC net counts versus detected photons. A biological application is reported; this shows the suitability of the system even to low light levels. PMID:6172589

Freitas, M I; Giordano, P A; Bottiroli, G

1981-11-01

197

Compiler-directed dynamic voltage\\/frequency scheduling for energy reduction in microprocessors  

Microsoft Academic Search

Dynamic voltage and frequency scaling of the CPU has been identified as one of the most effective ways to reduce energy consumption of a program. This paper discusses a com- pilation strategy that identifies scaling opportunities with- out significant overall performance penalty. Simulation re- sults show CPU energy savings of 3.97%-23.75% for the SPECfp95 benchmark suite with a performance penalty

Chung-Hsing Hsu; Ulrich Kremer; Michael S. Hsiao

2001-01-01

198

Voltage and frequency dependent dielectric properties of BST-0.5 thin films on alumina substrates  

Microsoft Academic Search

Dielectric properties of Ba0.5Sr0.5TiO3 (BST-0.5) polycrystalline thin films, deposited on alumina substrates by means of reactive pulsed laser deposition (PLD), were measured at GHz frequencies using an interdigital capacitor (IDC). By applying a voltage up to 40 V between the two groups of fingers at room temperature, a high tunability of ?27% was achieved at 5 GHz. A relative dielectric

Sbastien Delprat; Mossaab Ouaddari; Franois Vidal; Mohamed Chaker; Ke Wu

2003-01-01

199

A novel prototype design for a transformer for high voltage, high frequency, high power use  

Microsoft Academic Search

A prototype transformer has been designed and built which is novel in its combination of high voltage (50 kV), high frequency (20 kHz) and high power (25 kVA) specifications. The design technique utilized a spreadsheet approach which facilitated an iterative design procedure. The transformer used a ferrite core, nylon insulated secondary bobbins and pressurized sulfur hexafluoride encapsulation. It was designed

John C. Fothergill; Philip W. Devine; Paul W. Lefley

2001-01-01

200

Effect of Grid Voltage and Frequency Variations on the Output of Wind Generators  

Microsoft Academic Search

This article presents a study of the effect of voltage and frequency variation on the power output of the stall- and pitch-regulated fixed speed as well as the variable-speed wind-turbine generators (WGs). This study has been carried out using the steady-state model of each of these types of WGs. Each of these models facilitates the computation of the power output

K. C. Divya; P. S. Nagendra Rao

2008-01-01

201

Digital Signal Processor Based Fuzzy Voltage and Frequency Regulator for Self-excited Induction Generator  

Microsoft Academic Search

This article presents digital design and implementation of a digital signal processor based fuzzy logic load controller to regulate the voltage and frequency of a three-phase self-excited induction generator through an equal time ratio control AC chopper controllable load that is suitable for a stand-alone power mode employing an unregulated turbine such as micro-hydro power generation. The self-excited induction generator

D. K. Palwalia; S. P. Singh

2010-01-01

202

Sinusoidal grid definition  

E-print Network

This note shortly describes the sinusoidal equal-area grid on which the MERIS level 2 products are spatially binned. The average size of the grid bins is equal to 1/12, leading to 2160 rows in latitude, i.e. 1080 latitude rows in each hemisphere (the equatorial line is located between two rows of bins). This discretisation corresponds to roughly 9.277 km. Just below and above the equatorial line, the rows have 4320 bins. This number decreases regularly from the equator to the poles where the last latitude row have only 3 bins. For each row, the left side of the first bin is always aligned with longitude-180 while the right side of the last bin is aligned with longitude +180, covering all the latitude row area. The number of bins per row is always an integer number, computed in order to have the bin cell size as close as possible to 9.277 km, so that the effective longitudinal bin size may vary from one row to the next one. Applying this simple rules from South to North pole leads to a total of 5,940,422 bins. The pseudo-code below can be used to build the sinusoidal grid, i.e. to link the index of each bin (n) to its geolocation in longitude and latitude (bin_lon[n], bin_lat[n]).

Gilbert Barrot Acri-st; Issue /jan

203

Fig. 1 Circuit diagram of high-voltage generator with LCC resonant converter [3] Frequency / Duty Cycle Current-Mode Fuzzy Control  

E-print Network

1 Fig. 1 Circuit diagram of high-voltage generator with LCC resonant converter [3] Frequency / Duty resonant converter applied in very low frequency high voltage generators using switching frequency and duty of the novel approach. I. Introduction Mobile very low frequency (VLF) high-voltage (HV) generators

Paderborn, Universität

204

Wind-driven self-excited induction generator with voltage and frequency regulated by a reduced-rating voltage source inverter  

Microsoft Academic Search

This paper discusses the regulation of the voltage and frequency of a stand-alone fixed-pitch wind energy conversion system (WECS) based on a self-excited squirrel-cage induction machine. A shunt connected voltage source inverter (VSI) and a controllable dump load are used for regulation purposes. A battery bank is included in the dc side of the VSI so that it can absorb

Luiz A. C. Lopes; R. G. Almeida

2006-01-01

205

Breaking the ice: de-icing power transmission lines with high-frequency, high-voltage excitation  

E-print Network

Breaking the ice: de-icing power transmission lines with high-frequency, high-voltage excitation. High-frequency excitation at approximately 8-200 kHz has been proposed as a method to melt ice [1], [2]. The method works by a combination of two mechanisms. At these frequencies, ice is a lossy dielectric, causing

206

Performance of Voltage and Frequency Controller in Isolated Wind Power Generation for a Three-Phase Four-Wire System  

Microsoft Academic Search

This paper deals with a new control algorithm for a voltage and frequency controller (VFC) of an isolated wind energy conversion system (IWECS) using an isolated asynchronous generator to feed three-phase four-wire consumer loads. The reference source currents are estimated for the indirect current control of a voltage source converter (VSC) using the single-phase PQ theory to control the voltage

Shailendra Sharma; Bhim Singh

2011-01-01

207

Development of an automated AC-DC transfer measurement system for voltage and current at low frequencies  

Microsoft Academic Search

National Physical Laboratory India (NPLI) is the premier research & development center and the National Metrology Institute, which provides traceability in measurements by calibration throughout the country. Low Frequency voltage and current are very important quantities in electrical metrology. The standards for LF voltage and current are established by assigning AC-DC transfer difference to Thermal Converters (TCs) worldwide. The range

A. K. Govil; S. Ahmad; B. Pal; P. C. Kothari

2008-01-01

208

A sinusoidal oscillator using translinear current conveyors  

Microsoft Academic Search

This paper presents a new single-element-controlled current-controlled sinusoidal oscillator. The proposed oscillator is composed of one translinear current conveyor (CCCII), one CCCII with controlled current gain and two grounded capacitors. The oscillator is beneficial to monolithic integrated circuit implementation by the use of grounded capacitors. The oscillation condition and the oscillation frequency can be controlled electronically and independently through the

Montree Kumngern; Somyot Junnapiya

2010-01-01

209

Decoupled Voltage and Frequency Controller for Isolated Asynchronous Generators Feeding Three-Phase Four-Wire Loads  

Microsoft Academic Search

This paper deals with a decoupled voltage and frequency controller (DVFC) for an isolated asynchronous generator (IAG), also known as the self-excited induction generator (SEIG), used in constant power applications such as pico hydro uncontrolled turbine driven IAG for feeding three-phase four-wire loads. The proposed controller is used to control the voltage and frequency at the generator terminal independently. The

Gaurav Kumar Kasal; Bhim Singh

2008-01-01

210

On the application of radio frequency voltages to ion traps via helical resonators J.D. Siverns, L.R. Simkins, S. Weidt, W.K. Hensinger1  

E-print Network

On the application of radio frequency voltages to ion traps via helical resonators J.D. Siverns, L Ions confined using a Paul trap require a stable, high voltage and low noise radio frequency (RF trap a high radio frequency voltage is applied to electrodes in order to pro- vide the required

Hensinger, Winfried

211

An H.264\\/MPEG4 audio\\/visual CODEC LSI with module-wise dynamic voltage\\/frequency scaling  

Microsoft Academic Search

A single-chip H.264\\/MPEG-4 audio\\/visual LSI for mobile applications with a module-wise dynamic voltage\\/frequency scaling architecture is described. This LSI operates even during the voltage\\/frequency transition with no performance overhead by using a dynamic de-skewing system and an on-chip voltage regulator with slew-rate control. The IC consumes 90mW in decoding QVGA H.264 video at 15f\\/s and MPEG-4 AAC LC audio simultaneously.

Toshihide Fujiyoshi; Shinichiro Shiratake; Shuou Nomura; T. Nishikawa; Y. Kitasho; H. Arakida; Y. Okuda; Y. Tsuboi; M. Hamada; H. Hara; T. Fujita; F. Hatori; T. Shimazawa; K. Yahagi; H. Takeda; M. Murakata; F. Minami; N. Kawabe; T. Kitahara; K. Seta; M. Takahashi; Y. Oowaki

2005-01-01

212

All-Polymer modulator for high frequency low drive voltage applications  

NASA Astrophysics Data System (ADS)

Organic electro-optic material based optical modulators have been fervently pursued over the past two decades. The material properties of organic materials over crystalline electro-optic materials such as LiNbO3 have yielded devices with record low drive voltages and significant promise for high frequency operation that are ideal for implementation in many developing telecommunication technologies. This paper will discuss a TM electro-optic phase modulator based on a recently developed material IKD-1-50. A simple fabrication process that is compatible with wafer scale manufacturability using commercially available cladding materials, spin processing, standard photolithography, and dry etching will be presented. Non-centrosymmetric order is induced in the core material via a thermally enabled poling process that was developed based on work in simple slab waveguide material characterization devices, and optimized for polymer stack waveguide architectures. Basic phase modulators are characterized for half wave voltage and optical loss. In device r33 values are estimated from a combination of measured and simulated values. Additional work will be discussed including amplitude modulation and high frequency applications. The design for a Mach-Zehnder interferometer amplitude modulator that implements a multi mode interference cavity splitter will be presented along with plans for a microstrip transmission line traveling wave modulator.

Eng, David L. K.; Kozacik, Stephen; Shi, Shouyuan; Olbricht, Benjamin C.; Prather, Dennis W.

2014-03-01

213

A comparison of shock wave and sinusoidal-focused ultrasound-induced localized transfection of HeLa cells.  

PubMed

Both shock waves and sinusoidal continuous wave ultrasound can mediate DNA transfer into cells. The relative transfection efficiencies of different ultrasound modalities are unclear. The purpose of this paper is to compare the transfection efficiency of lithotripter shock waves and focused sinusoidal ultrasound in vitro. HeLa cells were transfected with beta-galactosidase and luciferase plasmid DNA reporter. Shock waves were generated by an electromagnetic sound source. Sixty to 360 pulses at 1 Hz pulse frequency were administered at 13, 16 or 19 kV capacitor voltage. Sinusoidal focused ultrasound was generated by a single focus piezoceramic air-backed disk transducer at a carrier frequency of 1.18 MHz operated in a pulsed mode. Compared to cells mixed with DNA only, shock waves induced up to eightfold more transfected cells at a cell viability of 5%, while sinusoidal-focused ultrasound induced up to 80-fold more transfected cells at a cell viability of 45%. The corresponding transfection efficiencies of the HeLa cells were 0.08% for shock waves and 3% for focused ultrasound. These results may contribute to the selection of the ultrasound modality as a localized, noninvasive and safe tool to mediate gene transfer. PMID:10626634

Huber, P E; Jenne, J; Debus, J; Wannenmacher, M F; Pfisterer, P

1999-11-01

214

Steering car-like systems with trailers using sinusoids  

Microsoft Academic Search

Methods for steering car-like robots with trailers are investigated. A connection is demonstrated between Murray and Sastry's (1990, 1991) work of steering with integrally related sinusoids and Sussmann and Liu's (1991) recent work on asymptotic behavior of systems with high-frequency sinusoids as inputs. The merits of coordinate transformations, relative to the convergence properties, are discussed. Simulation results for a car-like

D. Tilbury; J.-P. Laumond; R. Murray; S. Sastry; G. Walsh

1992-01-01

215

A high frequency active voltage doubler in standard CMOS using offset-controlled comparators for inductive power transmission.  

PubMed

In this paper, we present a fully integrated active voltage doubler in CMOS technology using offset-controlled high speed comparators for extending the range of inductive power transmission to implantable microelectronic devices (IMD) and radio-frequency identification (RFID) tags. This active voltage doubler provides considerably higher power conversion efficiency (PCE) and lower dropout voltage compared to its passive counterpart and requires lower input voltage than active rectifiers, leading to reliable and efficient operation with weakly coupled inductive links. The offset-controlled functions in the comparators compensate for turn-on and turn-off delays to not only maximize the forward charging current to the load but also minimize the back current, optimizing PCE in the high frequency (HF) band. We fabricated the active voltage doubler in a 0.5-?m 3M2P std . CMOS process, occupying 0.144 mm(2) of chip area. With 1.46 V peak AC input at 13.56 MHz, the active voltage doubler provides 2.4 V DC output across a 1 k? load, achieving the highest PCE = 79% ever reported at this frequency. In addition, the built-in start-up circuit ensures a reliable operation at lower voltages. PMID:23853321

Lee, Hyung-Min; Ghovanloo, Maysam

2013-06-01

216

Utilization of the voltage frequency converter or digital representation and documentation of transient reactor operation  

SciTech Connect

The ease and speed of handling transient data is enhanced by the use of a voltage to frequency converter (VFC). This analogue to digital semiconductor device provides an inexpensive and portable alternative to electro-mechanical recorders and hand entry of data into computer codes. The VFC used at The University of Arizona is a Teledyne Philbrick 4705/01. A zero to positive ten volt input signal provides a zero to one megahertz output signal which is TTL/DTL compatible. VFC is used at the University of Arizona to collect data for super prompt critical TRIGA excursions. The VFC provides a low cost, convenient method of transient data storage and retrieval for experimentation and laboratory demonstration.

Doane, Harry J. [Department of Nuclear and Energy Engineering, University of Arizona, Tucson, AZ (United States)

1986-07-01

217

Force sensor characterization under sinusoidal excitations.  

PubMed

The aim in the current work is the development of a method to characterize force sensors under sinusoidal excitations using a primary standard as the source of traceability. During this work the influence factors have been studied and a method to minimise their contributions, as well as the corrections to be performed under dynamic conditions have been established. These results will allow the realization of an adequate characterization of force sensors under sinusoidal excitations, which will be essential for its further proper use under dynamic conditions. The traceability of the sensor characterization is based in the direct definition of force as mass multiplied by acceleration. To do so, the sensor is loaded with different calibrated loads and is maintained under different sinusoidal accelerations by means of a vibration shaker system that is able to generate accelerations up to 100 m/s2 with frequencies from 5 Hz up to 2400 Hz. The acceleration is measured by means of a laser vibrometer with traceability to the units of time and length. A multiple channel data acquisition system is also required to simultaneously acquire the electrical output signals of the involved instrument in real time. PMID:25290287

Medina, Nieves; de Vicente, Jess

2014-01-01

218

Force Sensor Characterization Under Sinusoidal Excitations  

PubMed Central

The aim in the current work is the development of a method to characterize force sensors under sinusoidal excitations using a primary standard as the source of traceability. During this work the influence factors have been studied and a method to minimise their contributions, as well as the corrections to be performed under dynamic conditions have been established. These results will allow the realization of an adequate characterization of force sensors under sinusoidal excitations, which will be essential for its further proper use under dynamic conditions. The traceability of the sensor characterization is based in the direct definition of force as mass multiplied by acceleration. To do so, the sensor is loaded with different calibrated loads and is maintained under different sinusoidal accelerations by means of a vibration shaker system that is able to generate accelerations up to 100 m/s2 with frequencies from 5 Hz up to 2400 Hz. The acceleration is measured by means of a laser vibrometer with traceability to the units of time and length. A multiple channel data acquisition system is also required to simultaneously acquire the electrical output signals of the involved instrument in real time. PMID:25290287

Medina, Nieves; de Vicente, Jess

2014-01-01

219

Reduction of voltage stress in integrated high-quality rectifier-regulators by variable-frequency control  

Microsoft Academic Search

The Integrated High-Quality Rectifier-Regulators (IHQRRs) suffer from relatively high stress on the internal-energy storage capacitor and, consequently, on primary-side semiconductors. As a result, they are not practical in applications with the universal input-voltage range. In this paper, a variable-frequency control that reduces the voltage stress and makes the IHQRRs suitable for universal input-range applications is described. Evaluation results of a

Milan M. JovanoviC; Dan M. C. Tsang; Fred C. Lee

1994-01-01

220

System-level process-driven variability analysis for single and multiple voltage-frequency island systems  

Microsoft Academic Search

The problem of determining bounds for application completion times running on generic systems comprised of single or multiple voltage- frequency islands (VFIs) with arbitrary topologies is addressed in the context of manufacturing-driven variability. The approach provides an exact solution for the system-level timing yield in single clock, single voltage (SSV) and VFI systems with an underlying tree-based topology, and a

Diana Marculescu; Siddharth Garg

2006-01-01

221

Voltage-Frequency Planning for Thermal-Aware, Low-Power Design of Regular 3-D NoCs  

Microsoft Academic Search

Network-on-Chip combined with globally asynchronous locally synchronous paradigm is a promising architecture for easy IP integration and utilization with multiple voltage levels. For power reduction, multiple voltage-frequency levels are successfully applied to 2-D NoCs, but never with a generic approach to 3-D counterparts; in which low heat conductivity of insulator layers makes high dense temperature distribution at layers away from

Mohammad Arjomand; Hamid Sarbazi-Azad

2010-01-01

222

Process-Driven Variability Analysis of Single and Multiple Voltage-Frequency Island Latency-Constrained Systems  

Microsoft Academic Search

The problem of determining bounds for application completion times running on generic systems comprised of single or multiple voltage-frequency islands (VFIs) with arbitrary topologies is addressed in the context of manufacturing-driven variability. The approach provides an exact solution for the system-level timing yield in single clock, single voltage (SSV) and VFI systems with an underlying tree-based topology, and a tight

Diana Marculescu; Siddharth Garg

2008-01-01

223

Surface plasmon polaritons on soft-boundary graphene nanoribbons and their application as voltage controlled plasmonic switches and frequency demultiplexers  

E-print Network

A graphene sheet gated with a ridged ground plane, creating a soft-boundary (SB) graphene nanoribbon, is considered. By adjusting the ridge parameters and bias voltage a channel can be created on the graphene which can guide TM surface plasmon polaritons (SPP). Two types of modes are found; fundemental and higher-order modes with no apparent cutoff frequency and with energy distributed over the created channel, and edge modes with energy concen-trated at the soft-boundary edge. Dispersion curves, electric near-field patterns, and current distributions of these modes are determined. Since the location where energy is concentrated in the edge modes can be easily controlled electronically by the bias voltage and frequency, the edge-mode phenomena is used to propose a novel voltage controlled plasmonic switch and a plasmonic frequency demultiplexer.

Forati, Ebrahim

2013-01-01

224

Photoacoustic effect in a sinusoidally modulated structure  

NASA Astrophysics Data System (ADS)

We derive solutions to an inhomogeneous Mathieu equation that describes the photoacoustic effect in a one-dimensional phononic structure whose acoustic properties vary sinusoidally in space. Solutions show splitting of resonances, the space equivalent of subharmonic generation, and spatial confinement. Properties of the photoacoustic effect including the damping of waves inside the band gaps, the dispersion relation, the positions and widths of the gaps, the frequencies of resonances, and the space dependence of the acoustic waves can be found in closed form from known properties of Mathieu functions.

Wu, Binbin; Diebold, Gerald J.

2012-04-01

225

Estimation and Rejection of Unknown Sinusoidal Disturbances Using a Generalized Adaptive Forced Balancing Method  

Microsoft Academic Search

This paper presents a method for estimation and rejection of sinusoidal disturbances with unknown amplitudes and frequencies arising in feedback control systems. A method known as adaptive forced balancing has been used successfully to reject sinusoidal disturbances with known frequency and unknown amplitude in magnetic bearing control systems. The occurrence of such a disturbance is a result of a common

Elnaz Vahedforough; Bahram Shafai; Stuart Beale

2007-01-01

226

Optimal Estimation Of Voltage Phasors And Frequency Deviation Using Linear And Non-Linear Kalman Filtering: Theory And Limitations  

Microsoft Academic Search

This paper presents two techniques for optimal tracking of power system voltage phasors and frequency deviation. The first technique is based on a two-state linear Kalman filter model. The second technique is based on a three-state extended Kalman filter model. In the latter the frequency deviation is considered a third state variable and is recursively computed on-line. It is shown

Adly Girgis; T. Daniel Hwang

1984-01-01

227

Will your motor insulation survive a new adjustable-frequency drive?  

Microsoft Academic Search

The latest family of insulated-gate-bipolar-transistor (IGBT)-type adjustable-frequency drives (AFDs) produce voltage wavefronts that are extremely fast as a result of increasing carrier frequency. The frequency may be as high as 20 kHz. Motors which are designed for low-voltage sinusoidal power run more efficiently and quieter under this condition. However, the insulation in small- and medium-size motors may experience undesirable stress,

Sidney Bell; Jason Sung

1997-01-01

228

Radio frequency cavity analysis, measurement, and calibration of absolute Dee voltage for K-500 superconducting cyclotron at VECC, Kolkata.  

PubMed

Variable Energy Cyclotron Centre has commissioned a K-500 superconducting cyclotron for various types of nuclear physics experiments. The 3-phase radio-frequency system of superconducting cyclotron has been developed in the frequency range 9-27 MHz with amplitude and phase stability of 100 ppm and 0.2(0), respectively. The analysis of the RF cavity has been carried out using 3D Computer Simulation Technology (CST) Microwave Studio code and various RF parameters and accelerating voltages ("Dee" voltage) are calculated from simulation. During the RF system commissioning, measurement of different RF parameters has been done and absolute Dee voltage has been calibrated using a CdTe X-ray detector along with its accessories and known X-ray source. The present paper discusses about the measured data and the simulation result. PMID:23464200

Som, Sumit; Seth, Sudeshna; Mandal, Aditya; Paul, Saikat; Duttagupta, Anjan

2013-02-01

229

Radio frequency cavity analysis, measurement, and calibration of absolute Dee voltage for K-500 superconducting cyclotron at VECC, Kolkata  

SciTech Connect

Variable Energy Cyclotron Centre has commissioned a K-500 superconducting cyclotron for various types of nuclear physics experiments. The 3-phase radio-frequency system of superconducting cyclotron has been developed in the frequency range 9-27 MHz with amplitude and phase stability of 100 ppm and {+-}0.2{sup 0}, respectively. The analysis of the RF cavity has been carried out using 3D Computer Simulation Technology (CST) Microwave Studio code and various RF parameters and accelerating voltages ('Dee' voltage) are calculated from simulation. During the RF system commissioning, measurement of different RF parameters has been done and absolute Dee voltage has been calibrated using a CdTe X-ray detector along with its accessories and known X-ray source. The present paper discusses about the measured data and the simulation result.

Som, Sumit; Seth, Sudeshna; Mandal, Aditya; Paul, Saikat; Duttagupta, Anjan [Variable Energy Cyclotron Centre, Kolkata (India)

2013-02-15

230

Radio frequency cavity analysis, measurement, and calibration of absolute Dee voltage for K-500 superconducting cyclotron at VECC, Kolkata  

NASA Astrophysics Data System (ADS)

Variable Energy Cyclotron Centre has commissioned a K-500 superconducting cyclotron for various types of nuclear physics experiments. The 3-phase radio-frequency system of superconducting cyclotron has been developed in the frequency range 9-27 MHz with amplitude and phase stability of 100 ppm and 0.20, respectively. The analysis of the RF cavity has been carried out using 3D Computer Simulation Technology (CST) Microwave Studio code and various RF parameters and accelerating voltages ("Dee" voltage) are calculated from simulation. During the RF system commissioning, measurement of different RF parameters has been done and absolute Dee voltage has been calibrated using a CdTe X-ray detector along with its accessories and known X-ray source. The present paper discusses about the measured data and the simulation result.

Som, Sumit; Seth, Sudeshna; Mandal, Aditya; Paul, Saikat; Duttagupta, Anjan

2013-02-01

231

Effects of driving voltage frequency on the discharge characteristics of atmospheric dielectric-barrier-discharge plasma jet  

NASA Astrophysics Data System (ADS)

We present here the analysis of the discharge characteristics of a He dielectric-barrier-discharge (DBD) plasma jet operated in the frequency range of 0.6 to 30 kHz under an open-air condition. Discharge strength is sensitive to driving voltage frequency, and an increasing driving frequency induces a weak pulse discharge with a small plume length. We also performed time-resolved optical emission measurements in a transient pulse discharge driven by various voltage frequencies. A strong optical emission from O atoms is observed near the quartz-tube outlet at a low driving voltage frequency of about 5 kHz, where more than 90% of the total O emission intensity is detected in the after-discharge period. The observations indicate that low-frequency discharge operation can generate a large number of reactive excited O atoms near the quartz-tube outlet, and this is ascribed to the chemical reactions in the after-discharge period.

Uchida, Giichiro; Takenaka, Kosuke; Kawabata, Kazufumi; Miyazaki, Atsushi; Setsuhara, Yuichi

2014-11-01

232

The sinusoid and the phasor  

E-print Network

Mathieu equation is widely used to study several natural phenomenon. In this paper, we show that replacing the sinusoid in the Mathieu equation with a phasor can lead to solutions that behave in a totally different way. Solutions of Mathieu equation are either bounded or grow unboundedly at an exponential rate. Solutions of this new equation are always unbounded and grow linearly with time.

Kushal Shah; Harishankar Ramachandran

2010-06-08

233

Distributed Voltage and Frequency Control of Offshore Wind Farms Connected With a Diode-Based HVdc Link  

Microsoft Academic Search

This paper introduces a new technique for the distributed voltage and frequency control of the local ac-grid in offshore wind farms based on synchronous generators. The proposed control technique allows the connection of the offshore wind farm using a diode based HVdc rectifier. The use of microgrid control techniques allowed the system comprising the wind farm and the diode HVdc

Ramon Blasco-Gimenez; S. Ao?-Villalba; J. Rodri?guez-D'Derle?e; F. Morant; S. Bernal-Perez

2010-01-01

234

Long Pulse XeCl Laser Frequency Down Conversion and Low Voltage, Low Energy X-Ray Preionization Source.  

National Technical Information Service (NTIS)

The first program, Long Pulse XeCl Laser Frequency Down Conversion, was initiated following the encouraging Raman shifting results. The second program, Low Voltage, Low Energy X-Ray Preionization Source was undertaken after it was realized that the energy...

J. I. Levatter, S. C. Lin

1981-01-01

235

Interactive presentation: System-level process variation driven throughput analysis for single and multiple voltage-frequency island designs  

Microsoft Academic Search

Manufacturing process variations are the primary cause of timing yield loss in aggressively scaled technologies. In this paper, we analyze the impact of process variations on the throughput (rate) characteristics of embedded systems comprised of multiple voltage-frequency islands (VFIs) represented as component graphs. We provide an efficient, yet accurate method to compute the throughput of an application in a probabilistic

Siddharth Garg; Diana Marculescu

2007-01-01

236

System-Level Process Variation Driven Throughput Analysis for Single and Multiple Voltage-Frequency Island Designs  

Microsoft Academic Search

Manufacturing process variations are the primary cause of timing yield loss in aggressively scaled technologies. In this paper, we analyze the impact of process variations on the throughput (rate) characteristics of embedded systems comprised of multiple voltage-frequency islands (VFIs) represented as component graphs. We provide an efficient, yet accurate method to compute the throughput of an application in a probabilistic

Siddharth Garg; Diana Marculescu

2007-01-01

237

Dynamic voltage and frequency scaling under a precise energy model considering variable and fixed components of the system power dissipation  

Microsoft Academic Search

This paper presents a dynamic voltage and frequency scaling (DVFS) *technique that minimizes the total system energy consumption for performing a task while satisfying a given execution time constraint. We first show that in order to guarantee minimum energy for task execution by using DVFS it is essential to divide the system power into active and standby power components. Next,

Kihwan Choi; Wonbok Lee; Ramakrishna Soma; Massoud Pedram

2004-01-01

238

Analysis of a voltage controlled frequency foldback technique that improves short circuit protection for buck derived converters  

Microsoft Academic Search

The output VI characteristics of most high frequency buck-derived PWM power converters exhibit a current tail during fault conditions. A current tail is actually an increase in the average output current as the output voltage decreases toward zero. Ideally, the controller's peak current limit function should prevent the average output current from exceeding a specified limit. In reality, the tail

Philip Cooke

1996-01-01

239

RF voltage modulation at discrete frequencies with applications to crystal channeling extraction  

SciTech Connect

RF voltage modulation at a finite number of discrete frequencies is described in a Hamiltonian resonance framework. The theory is applied to the problem of parasitic extraction of a fixed target beam from a high energy proton collider, using a bent crystal as a thin ``septum`` within an effective width of about one micron. Three modes of employment of discrete resonances are proposed.First, a single relatively strong static ``drive`` resonance may be used to excite a test proton so that it will penetrate deeply into the channeling crystal. Second, a moderately strong ``feed`` resonance with a ramped modulation tune may be used to adiabatically trap protons near the edge of the beam core, and transport them to the drive resonance. Third, several weak resonances may be overlapped to create a chaotic amplitude band, either to transport protons to the drive resonance, or to provide a ``pulse stretching`` buffer between a feed resonance and the drive resonance. Extraction efficiency is semi- quantitatively described in terms of characteristic ``penetration,`` ``depletion,`` and ``repetition`` times. simulations are used to quantitatively confirm the fundamental results of the theory, and to show that a prototypical extraction scheme using all three modes promises good extraction performance.

Gabella, W.; Rosenzweig, J. [California Univ., Los Angeles, CA (United States). Dept. of Physics; Kick, R. [Illinois Math and Science Academy, Aurora, Illinois (United States); Peggs, S. [Fermi National Accelerator Lab., Batavia, IL (United States)

1992-05-01

240

RF voltage modulation at discrete frequencies with applications to crystal channeling extraction  

SciTech Connect

RF voltage modulation at a finite number of discrete frequencies is described in a Hamiltonian resonance framework. The theory is applied to the problem of parasitic extraction of a fixed target beam from a high energy proton collider, using a bent crystal as a thin septum'' within an effective width of about one micron. Three modes of employment of discrete resonances are proposed.First, a single relatively strong static drive'' resonance may be used to excite a test proton so that it will penetrate deeply into the channeling crystal. Second, a moderately strong feed'' resonance with a ramped modulation tune may be used to adiabatically trap protons near the edge of the beam core, and transport them to the drive resonance. Third, several weak resonances may be overlapped to create a chaotic amplitude band, either to transport protons to the drive resonance, or to provide a pulse stretching'' buffer between a feed resonance and the drive resonance. Extraction efficiency is semi- quantitatively described in terms of characteristic penetration,'' depletion,'' and repetition'' times. simulations are used to quantitatively confirm the fundamental results of the theory, and to show that a prototypical extraction scheme using all three modes promises good extraction performance.

Gabella, W.; Rosenzweig, J. (California Univ., Los Angeles, CA (United States). Dept. of Physics); Kick, R. (Illinois Math and Science Academy, Aurora, Illinois (United States)); Peggs, S. (Fermi National Accelerator Lab., Batavia, IL (United States))

1992-05-01

241

The influence of the relative phase between the driving voltages on electron heating in asymmetric dual frequency capacitive discharges  

NASA Astrophysics Data System (ADS)

The influence of the relative phase between the driving voltages on electron heating in asymmetric phase-locked dual frequency capacitively coupled radio frequency plasmas operated at 2 and 14 MHz is investigated. The basis of the analysis is a nonlinear global model with the option to implement a relative phase between the two driving voltages. In recent publications it has been reported that nonlinear electron resonance heating can drastically enhance the power dissipation to electrons at moments of sheath collapse due to the self-excitation of nonlinear plasma series resonance (PSR) oscillations of the radio frequency current. This work shows that depending on the relative phase of the driving voltages, the total number and exact moments of sheath collapse can be influenced. In the case of two consecutive sheath collapses a substantial increase in dissipated power compared with the known increase due to a single PSR excitation event per period is observed. Phase resolved optical emission spectroscopy (PROES) provides access to the excitation dynamics in front of the driven electrode. Via PROES the propagation of beam-like energetic electrons immediately after the sheath collapse is observed. In this work we demonstrate that there is a close relation between moments of sheath collapse, and thus excitation of the PSR, and beam-like electron propagation. A comparison of simulation results to experiments in a single and dual frequency discharge shows good agreement. In particular the observed influence of the relative phase on the dynamics of a dual frequency discharge is described by means of the presented model. Additionally, the analysis demonstrates that the observed gain in dissipation is not accompanied by an increase in the electrode's dc-bias voltage which directly addresses the issue of separate control of ion flux and ion energy in dual frequency capacitively coupled radio frequency plasmas.

Ziegler, D.; Trieschmann, J.; Mussenbrock, T.; Brinkmann, R. P.; Schulze, J.; Czarnetzki, U.; Semmler, E.; Awakowicz, P.; O'Connell, D.; Gans, T.

2010-08-01

242

Overvoltages in inverter fed induction machines using high frequency power electronic components  

Microsoft Academic Search

Inverter supplied induction motors have become common. One of the tendencies that can be observed over the years, is that the switching frequencies of the power electronic components increase. This allows the manufacturers to build more compact inverters with an improved sinusoidal wave shape of the output voltage and\\/or current. The increase in the switching frequency is made possible by

P. Van Poucke; R. Belmans; W. Geysen; E. Ternier

1994-01-01

243

High frequency capacitance-voltage characteristics of thermally grown SiO2 films on beta-SiC  

NASA Technical Reports Server (NTRS)

Silicon dioxide films grown under dry and wet oxidation environment on beta-SiC films have been studied. The beta-SiC films had been heteroepitaxially grown on both on-axis and 2-deg off-axis (001) Si substrates. Capacitance-voltage and conductance-voltage characteristics of metal-oxide-semiconductor structures were measured in a frequency range of 10 kHz to 1 MHz. From these measurements, the interface trap density and the effective fixed oxide charge density were observed to be generally lower for off-axis samples.

Tang, S. M.; Berry, W. B.; Kwor, R.; Zeller, M. V.; Matus, L. G.

1990-01-01

244

Silicon Carbide Emitter Turn-off Thyristor, A Promising Technology For High Voltage and High Frequency Applications  

Microsoft Academic Search

A novel MOS-controlled SiC thyristor device, the SiC emitter turn-off thyristor (ETO), as a promising technology for future high voltage high frequency switching applications has been developed. The world's first 4.5-kV SiC p type ETO prototype based on a 0.36 cm2 SiC p type GTO shows a forward voltage drop of 4.6 V at a current density of 25 A\\/cm2

Jun Wang; Gangyao Wang; Jun Li; A. Q. Huang

2009-01-01

245

Speech transformations based on a sinusoidal representation  

NASA Astrophysics Data System (ADS)

A new speech analysis/synthesis technique is presented which provides the basis for a general class of speech transformation including time-scale modification, frequency scaling, and pitch modification. These modifications can be performed with a time-varying change, permitting continuous adjustment of a speaker's fundamental frequency and rate of articulation. The method is based on a sinusoidal representation of the speech production mechanism that has been shown to produce synthetic speech that preserves the waveform shape and is essentially perceptually indistinguishable from the original. Although the analysis/synthesis system originally was designed for single-speaker signals, it is equally capable of recovering and modifying nonspeech signals such as music; multiple speakers, marine biologic sounds, and speakers in the presence of interferences such as noise and musical backgrounds.

Quatieri, T. E.; McAulay, R. J.

1986-05-01

246

Optimally scaled low-voltage vertical power MOSFETs for high-frequency power conversion  

Microsoft Academic Search

The systematic optimization of low-voltage silicon power MOSFET technology is described. It is shown that device scaling using advanced fabrication technologies can result in nearly optimal performance from low-voltage silicon power MOSFETs. The details discussed include: (1) system impact; (2) unit cell optimization; (3) device and process modeling; (4) fabrication technology development; and (5) performance results. The device technologies optimized

K. Shenai

1990-01-01

247

A new hybrid gate drive scheme for high frequency buck voltage regulators  

Microsoft Academic Search

This paper presents a new hybrid drive scheme for a synchronous buck voltage regulator (VR). The proposed current-source driver is used to drive the control MOSFET to achieve fast switching speed and reduce the switching loss significantly due to the parasitic inductance in addition to gate energy recovery. Conventional voltage driver is used for synchronous rectifier (SR) MOSFET for its

Zhiliang Zhang; Wilson Eberle; Ping Lin; Yan-Fei Liu; Paresh C. Sen

2008-01-01

248

The Effect of High Voltage, High Frequency Pulsed Electric Field on Slain Ovine Cortical Bone  

PubMed Central

High power, high frequency pulsed electric fields known as pulsed power (PP) has been applied recently in biology and medicine. However, little attention has been paid to investigate the application of pulse power in musculoskeletal system and its possible effect on functional behavior and biomechanical properties of bone tissue. This paper presents the first research investigating whether or not PP can be applied safely on bone tissue as a stimuli and what will be the possible effect of these signals on the characteristics of cortical bone by comparing the mechanical properties of this type of bone pre and post expose to PP and in comparison with the control samples. A positive buck-boost converter was applied to generate adjustable high voltage, high frequency pulses (up to 500 V and 10 kHz). The functional behavior of bone in response to pulse power excitation was elucidated by applying compressive loading until failure. The stiffness, failure stress (strength) and the total fracture energy (bone toughness) were determined as a measure of the main bone characteristics. Furthermore, an ultrasonic technique was applied to determine and comprise bone elasticity before and after pulse power stimulation. The elastic property of cortical bone samples appeared to remain unchanged following exposure to pulse power excitation for all three orthogonal directions obtained from ultrasonic technique and similarly from the compression test. Nevertheless, the compressive strength and toughness of bone samples were increased when they were exposed to 66 h of high power pulsed electromagnetic field compared to the control samples. As the toughness and the strength of the cortical bone tissue are directly associated with the quality and integrity of the collagen matrix whereas its stiffness is primarily related to bone mineral content these overall results may address that although, the pulse power stimulation can influence the arrangement or the quality of the collagen network causing the bone strength and toughness augmentation, it apparently did not affect the mineral phase of the cortical bone material. The results also confirmed that the indirect application of high power pulsed electric field at 500 V and 10 kHz through capacitive coupling method was safe and did not destroy the bone tissue construction. PMID:24761375

Asgarifar, Hajarossadat; Oloyede, Adekunle; Zare, Firuz

2014-01-01

249

The effect of high voltage, high frequency pulsed electric field on slain ovine cortical bone.  

PubMed

High power, high frequency pulsed electric fields known as pulsed power (PP) has been applied recently in biology and medicine. However, little attention has been paid to investigate the application of pulse power in musculoskeletal system and its possible effect on functional behavior and biomechanical properties of bone tissue. This paper presents the first research investigating whether or not PP can be applied safely on bone tissue as a stimuli and what will be the possible effect of these signals on the characteristics of cortical bone by comparing the mechanical properties of this type of bone pre and post expose to PP and in comparison with the control samples. A positive buck-boost converter was applied to generate adjustable high voltage, high frequency pulses (up to 500 V and 10 kHz). The functional behavior of bone in response to pulse power excitation was elucidated by applying compressive loading until failure. The stiffness, failure stress (strength) and the total fracture energy (bone toughness) were determined as a measure of the main bone characteristics. Furthermore, an ultrasonic technique was applied to determine and comprise bone elasticity before and after pulse power stimulation. The elastic property of cortical bone samples appeared to remain unchanged following exposure to pulse power excitation for all three orthogonal directions obtained from ultrasonic technique and similarly from the compression test. Nevertheless, the compressive strength and toughness of bone samples were increased when they were exposed to 66 h of high power pulsed electromagnetic field compared to the control samples. As the toughness and the strength of the cortical bone tissue are directly associated with the quality and integrity of the collagen matrix whereas its stiffness is primarily related to bone mineral content these overall results may address that although, the pulse power stimulation can influence the arrangement or the quality of the collagen network causing the bone strength and toughness augmentation, it apparently did not affect the mineral phase of the cortical bone material. The results also confirmed that the indirect application of high power pulsed electric field at 500 V and 10 kHz through capacitive coupling method was safe and did not destroy the bone tissue construction. PMID:24761375

Asgarifar, Hajarossadat; Oloyede, Adekunle; Zare, Firuz

2014-04-01

250

PERCEPTUAL NORMALIZATION OF VOWELS PRODUCED BY SINUSOIDAL VOICES*  

E-print Network

, such as brief formant frequency * Journal of Experimental Psychology: Human Perception and Performance, 1987, 13 support the general claim that sinusoidal replicas of natural speech signals al'e pel,40-61. ** Department of Psychology, Barnard College t Columbia College Acknowledgment. The aut.hors wish t.o t

251

Sinusoidal reaction formulation for radiation and scattering from conducting surfaces  

NASA Technical Reports Server (NTRS)

The piecewise-sinusoidal reaction technique was developed for low-frequency scattering and radiation from perfectly conducting bodies of arbitrary shape. The theory and numerical results for scattering patterns of rectangular plates and radiation patterns of corner-reflector antennas are presented.

Richmond, J. H.; Wang, N.

1974-01-01

252

Speech analysis\\/Synthesis based on a sinusoidal representation  

Microsoft Academic Search

A sinusoidal model for the speech waveform is used to develop a new analysis\\/synthesis technique that is characterized by the amplitudes, frequencies, and phases of the component sine waves. These parameters are estimated from the short-time Fourier transform using a simple peak-picking algorithm. Rapid changes in the highly resolved spectral components are tracked using the concept of \\

R. McAulay; T. Quatieri

1986-01-01

253

Direct Estimation of Noisy Sinusoids Using Abductive Networks  

E-print Network

only during training, with actual estimation simplified and speeded up. This allows using simple of the sinusoid cycle is measured. Index Terms: Spectral analysis, Frequency estimation, Parameter estimation waves, processing of nuclear magnetic resonance (NMR) signals, speech and image processing, modal

Abdel-Aal, Radwan E.

254

Parameter estimation of exponentially damped sinusoids using HSVD based extended complex Kalman filter  

Microsoft Academic Search

The present study proposes two alternate model structures to represent exponentially damped sinusoids and proposes a novel method of estimating the parameters of the damped sinusoids by combining Hankel singular value decomposition (HSVD) with the extended complex Kalman filter (ECKF). The ECKF is capable of estimating the parameters and can effectively track the variations of damping constants and frequencies. However,

Jian Zhang; A. K. Swain; S. K. Nguang

2008-01-01

255

Estimating the parameters of exponentially damped sinusoids and pole-zero modeling in noise  

Microsoft Academic Search

We have presented techniques [1] - [6] based on linear prediction (LP) and singular value decomposition (SVD) for accurate estimation of closely spaced frequencies of sinusoidal signals in noise. In this note we extend these techniques to estimate the parameters of exponentially damped sinusoidal signals in noise. The estimation procedure presented here makes use of \\

RAMDAS KUMARESAN; DONALD W. TUFTS

1982-01-01

256

Distributed voltage and frequency control of off-shore wind farms connected with a diode based HVDC link  

Microsoft Academic Search

This paper introduces a new technique for the distributed voltage and frequency control of the local ac-grid in off-shore wind farms based on synchronous generators. The proposed control technique allows the connection of the off-shore wind farm using a diode based HVDC rectifier. The system comprising the wind farm and the diode HVDC rectifier can be operated in current or

R. Blasco-Gimenez; S. An?o?-Villalba; J. Rodri?guez-D?Derle?e; F. Morant; S. Bernal

2010-01-01

257

Wide-Linear-Range Subthreshold OTA for Low-Power, Low-Voltage, and Low-Frequency Applications  

Microsoft Academic Search

We propose a novel configuration of linearized subthreshold operational transconductance amplifier (OTA) for low-power, low-voltage, and low-frequency applications. By using multiple input floating-gate (MIFG) MOS devices and implementing a cubic-distortion-term-canceling technique, the linear range of the OTA is up to 1.1 Vpp under a 1.5-V supply for less than 1% of transconductance variation, according to testing results from a circuit

A. ElMourabit; Guo-Neng Lu; Patrick Pittet

2005-01-01

258

The design of constant frequency hysteresis current controller with voltage space vector in PV grid-connected inverter  

Microsoft Academic Search

A new constant-frequency hysteresis current control algorithm for PV grid-connected inverter is proposed, in which the complex plane is divided into six sectors based on line voltage space vector of electric power grid, and two-phase switches are decoupled respectively in every sector to control corresponding line currents, and the hysteresis band is modified by prediction, so that the output current

Genping Wang; Lingzhi Yi; Xiao Zou; Sufeng He; Ming Li

2008-01-01

259

High-Frequency Resonant SEPIC Converter With Wide Input and Output Voltage Ranges  

E-print Network

This paper presents a resonant single-ended-primary-inductor-converter (SEPIC) converter and control method suitable for high frequency (HF) and very high frequency (VHF) dc-dc power conversion. The proposed design provides ...

Hu, Jingying

260

High-Frequency Stimulation Produces a Transient Blockade of Voltage-Gated Currents in Subthalamic Neurons  

E-print Network

tetanus, consist- ing of 100- s bipolar stimuli at a frequency of 100­250 Hz during 1 min, produced a full. Thus a high-frequency tetanus produces a blockade of the spontaneous activities of STN neurons

Cossart, Rosa

261

Induction generator produces constant-frequency voltage from variable-speed drive  

NASA Technical Reports Server (NTRS)

Two-stage polyphase generator is usable as induction motor operable over range of speeds while powered from constant frequency source. It requires neither slip rings nor special adjustable-frequency power supplies or external reactive sources.

Riaz, M.

1970-01-01

262

High frequency capacitor-diode voltage multiplier dc-dc converter development  

NASA Technical Reports Server (NTRS)

A power conditioner was developed which used a capacitor diode voltage multiplier to provide a high voltage without the use of a step-up transformer. The power conditioner delivered 1200 Vdc at 100 watts and was operated from a 120 Vdc line. The efficiency was in excess of 90 percent. The component weight was 197 grams. A modified boost-add circuit was used for the regulation. A short circuit protection circuit was used which turns off the drive circuit upon a fault condition, and recovers within 5 ms after removal of the short. High energy density polysulfone capacitors and high speed diodes were used in the multiplier circuit.

Kisch, J. J.; Martinelli, R. M.

1977-01-01

263

Series Resonant ZCS-PFM DC-DC Power Converter with High-Frequency High-Voltage Transformer Link for High-Power Magnetron Drive  

NASA Astrophysics Data System (ADS)

This paper presents a single lossless inductive snubber-assisted ZCS-PFM series resonant DC-DC power converter with a high-frequency high-voltage transformer link for industrial-use high power magnetron drive. The current flowing through the active power switches rises gradually at a turned-on transient state with the aid of a single lossless snubber inductor, and ZCS turn-on commutation based on overlapping current can be achieved in wide range pulse frequency modulation control scheme. The high-frequency high-voltage transformer primary side resonant current always becomes continuous operation mode, by electromagnetic loose coupling design of the high-frequency high-voltage transformer and the magnetizing inductance of the high-frequency high-voltage transformer. As a result, this high-voltage power converter circuit for the magnetron is possible to achieve a complete zero current soft switching under a condition of the broad width gate voltage signals. Furthermore, this high-voltage DC-DC power converter circuit can regulate the output power from zero to full over audible frequency range because of two resonant frequency circuit design. Its operating performances are evaluated and discussed on the basis of the power loss analysis simulation and the experimental results from a practical point of view.

Ishitobi, Manabu; Myoi, Takeshi; Soshin, Koji; Hiraki, Eiji; Nakaoka, Mutsuo

264

Radio-Frequency Interference (RFI) From Extra-High-Voltage (EHV) Transmission Lines  

E-print Network

on AM radio. Today audible noise is of greater concern because many states, counties, and municipalities radio astronomy (in the United States, at least) in 1984 when the El Paso Electric Company proposed for the task as the Chief High Voltage Phenomena Engineer of BPA's Division of Laboratories with many years

Ellingson, Steven W.

265

Optimized silicon low-voltage power MOSFET's for high-frequency power conversion  

Microsoft Academic Search

The specific results obtained from a systematic optimization of low-voltage silicon power MOSFET technologies are discussed. The areas discussed include system impact, unit cell optimization, device and process modeling, fabrication technology development, and measured results. The device technologies optimized include 30 V, 50 V, and 100 V vertical power DMOSFETs with refractory silicide gate and contact metallizations. Devices with the

Krishna Shenai; Charles S. Korman; John P. Walden; Alexander J. Yerman; B. Jayant Baliga

1989-01-01

266

Esterline Angus Voltage And Frequency Transducer (Model S-21289) AND Recorder (Model E-1102R).  

National Technical Information Service (NTIS)

The report describes the evaluation tests of the Esterline Angus Voltage Transducer Model S-21289 in conjunction with the Esterline Angus Galvanometer Recorder Model E-1102R. The tests and test procedures used are discussed briefly and the results are com...

D. M. Presley

1971-01-01

267

Analysis and design of a low-voltage high-frequency LDMOS transistor  

Microsoft Academic Search

For a low voltage lateral double-diffused MOS (LDMOS) transistor, the output performance has been improved in terms of fMAX. This is done by decreasing the output capacitance and thus decreasing the total output conductance. Extraction of the model parameters has been made and the most efficient parameter to improve was identified and linked to a specific part of the transistor

Lars Vestling; Johan Ankarcrona; Jrgen Olsson

2002-01-01

268

Varying penetration ratios of wind turbine technologies for voltage and frequency stability  

Microsoft Academic Search

This paper examines the ability of a power system to accommodate wind generation with varying ratios of doubly-fed induction generator and fixed speed induction generator turbines from both static and dynamic aspects. By controlling the ratio between the two types of turbines, voltage stability is maintained for steady-state conditions for a large range of varying wind speeds. Using the ratio

Eknath Vittal; Andrew Keane; Mark O'Malley

2008-01-01

269

Power quality issues with adjustable frequency drives -- Coping with power loss and voltage transient occurrences  

SciTech Connect

The power quality issue is not new to consumers of electrical power. From individual home owners to large industrial complexes, power quality problems can cause eyebrows to raise or bring industrial giants to their knees. Power quality comes in many forms. It can appear in the form of a voltage source which decreases to a small fraction of its normal strength or as a voltage transient, briefly far exceeding its normal value, ready to break down electrical insulation. It can appear as an oscillating voltage or a traveling voltage wave beating against barriers designed as added protection. Defining a single set of rules to control the characteristics of power quality is difficult, since its impact on electrical equipment changes as the characteristics of equipment change. A key to understanding how to cope with power quality issues begins with understanding the nature of electrical products. The nature of any product is defined by how its components are selected and how the designers apply those components. Reviewing design criteria, component selection and product characteristics can provide this basis of understanding.

Murphy, H.G. (Allen-Bradley Co., Mequon, WI (United States))

1993-07-01

270

Challenges and opportunities for multi-functional oxide thin films for voltage tunable radio frequency/microwave components  

NASA Astrophysics Data System (ADS)

There has been significant progress on the fundamental science and technological applications of complex oxides and multiferroics. Among complex oxide thin films, barium strontium titanate (BST) has become the material of choice for room-temperature-based voltage-tunable dielectric thin films, due to its large dielectric tunability and low microwave loss at room temperature. BST thin film varactor technology based reconfigurable radio frequency (RF)/microwave components have been demonstrated with the potential to lower the size, weight, and power needs of a future generation of communication and radar systems. Low-power multiferroic devices have also been recently demonstrated. Strong magneto-electric coupling has also been demonstrated in different multiferroic heterostructures, which show giant voltage control of the ferromagnetic resonance frequency of more than two octaves. This manuscript reviews recent advances in the processing, and application development for the complex oxides and multiferroics, with the focus on voltage tunable RF/microwave components. The over-arching goal of this review is to provide a synopsis of the current state-of the-art of complex oxide and multiferroic thin film materials and devices, identify technical issues and technical challenges that need to be overcome for successful insertion of the technology for both military and commercial applications, and provide mitigation strategies to address these technical challenges.

Subramanyam, Guru; Cole, M. W.; Sun, Nian X.; Kalkur, Thottam S.; Sbrockey, Nick M.; Tompa, Gary S.; Guo, Xiaomei; Chen, Chonglin; Alpay, S. P.; Rossetti, G. A.; Dayal, Kaushik; Chen, Long-Qing; Schlom, Darrell G.

2013-11-01

271

Issues on the design and implementation of radio frequency CMOS LC tank voltage-controlled oscillators  

Microsoft Academic Search

This paper is a general tutorial on the design and implementation of integrated submicron CMOS voltage-controlled oscillators\\u000a based on LC resonator tanks. Although special reference to phase noise reduction is made, the discussion also includes issues\\u000a such as power consumption, oscillator reliability and adaptivity together with tuning range. Important guidelines on oscillator\\u000a and LC tank design are discussed, with emphasis

Owen Casha; Ivan Grech; Joseph Micallef

2009-01-01

272

Currentvoltage characteristics of lead zirconate titanate/nickel bilayered hollow cylindrical magnetoelectric composites  

NASA Astrophysics Data System (ADS)

Current-voltage measurements obtained from lead zirconate titanate/nickel bilayered hollow cylindrical magnetoelectric composite showed that a sinusoidal current applied to the copper coil wrapped around the hollow cylinder circumference induces voltage across the lead zirconate titanate layer thickness. The current-voltage coefficient and the maximum induced voltage in lead zirconate titanate at 1 kHz and resonance (60.1 kHz) frequencies increased linearly with the number of the coil turns and the applied current. The resonance frequency corresponds to the electromechanical resonance frequency. The current-voltage coefficient can be significantly improved by optimizing the magnetoelectric structure geometry and/or increasing the number of coil turns. Hollow cylindrical lead zirconate titanate/nickel structures can be potentially used as current sensors.

Pan, De-An; Zhang, Shen-Gen; Tian, Jian-Jun; Sun, Jun-Sai; Alex, Volinsky A.; Qiao, Li-Jie

2010-02-01

273

Low-power high-voltage high-frequency power supply for ozone generation  

Microsoft Academic Search

A low-cost high-frequency power supply for ozone generation is presented in this paper. The paper addresses two important issues. Firstly, the ozone reactor is tested at high frequency and a new model of this type of load is proposed. Secondly, the power supply stage is presented and analyzed, obtaining some important characteristics that allow the correct design of this power

J. Marcos Alonso; J. Cardesin; E. L. Corominas; M. Rico-Secades; J. Garcia

2004-01-01

274

Voltage and frequency stabilizer based on Fuzzy logic control for three-level NPC converters in stand-alone wind energy systems  

Microsoft Academic Search

The paper proposes a Fuzzy logic approach for controlling three-level NPC converters in stand alone wind energy systems. A key function of this controller is to maintain constant voltage and frequency for customers while maintaining smooth voltage waveform with less filtering requirements. The principle of the proposed Fuzzy controller is based on a modified PI approach in which the error

Ameen Gargoom; Abu Mohammad Osman Haruni; M. E. Haque; M. Negnevitsky

2010-01-01

275

DC Link Voltage and Supply-Side Current HarmonicsMinimization of Three Phase PWM BoostRectifiers Using Frequency Domain BasedRepetitive Current Controllers  

Microsoft Academic Search

This paper presents a digital plug-in frequency domain based repetitive control scheme for minimizing the odd order harmonics in the supply line side currents of the three phase pulsewidth modulation (PWM) boost rectifier under the distorted and unbalanced supply voltage conditions. Based on the mathematical model of the three-phase PWM boost rectifier under the generalized supply voltage conditions, the control

X. H. Wu; S. K. Panda; J. X. Xu

2008-01-01

276

Verification of voltage/frequency requirement for emergency diesel generator in nuclear power plant using dynamic modeling  

NASA Astrophysics Data System (ADS)

One major cause of the plant shutdown is the loss of electrical power. The study is to comprehend the coping action against station blackout including emergency diesel generator, sequential loading of safety system and to ensure that the emergency diesel generator should meet requirements, especially voltage and frequency criteria using modeling tool. This paper also considered the change of the sequencing time and load capacity only for finding electrical design margin. However, the revision of load list must be verified with safety analysis. From this study, it is discovered that new load calculation is a key factor in EDG localization and in-house capability increase.

Hur, Jin-Suk; Roh, Myung-Sub

2014-02-01

277

Improvement to speech-music discrimination using sinusoidal model based features  

Microsoft Academic Search

This paper addresses a model-based audio content analysis for classification of speech-music mixed audio signals into speech\\u000a and music. A set of new features is presented and evaluated based on sinusoidal modeling of audio signals. The new feature\\u000a set, including variance of the birth frequencies and duration of the longest frequency track in sinusoidal model, as a measure\\u000a of the

Jalil Shirazi; Shahrokh Ghaemmaghami

2010-01-01

278

A novel non-fragile single-loop voltage and frequency controller for induction generator based isolated renewable energy conversion system  

Microsoft Academic Search

Poor voltage and frequency regulation under source and load perturbations limit the use of self excited induction generator (SEIG) in isolated and dispersed generation, which can exploit wind\\/microhydro type renewable energy sources. In the present work, a Generalized Impedance Controller (GIC), which is a pulse-width-modulated voltage-source-inverter with a dc-link battery, is used to regulate both, amplitude and frequency of the

J. K. Chatterjee; Priyesh J. Chauhan

2010-01-01

279

Analysis of event-related potentials (ERP) by damped sinusoids.  

PubMed

Several researchers propose that event-related potentials (ERPs) can be explained by a superposition of transient oscillations at certain frequency bands in response to external or internal events. The transient nature of the ERP is more suitable to be modelled as a sum of damped sinusoids. These damped sinusoids can be completely characterized by four sets of parameters, namely the amplitude, the damping coefficient, the phase and the frequency. The Prony method is used to estimate these parameters. In this study, the long-latency auditory-evoked potentials (AEP) and the auditory oddball responses (P300) of 10 healthy subjects are analysed by this method. It is shown that the original waveforms can be reconstructed by summing a small number of damped sinusoids. This allows for a parsimonious representation of the ERPs. Furthermore, the method shows that the oddball target responses contain higher amplitude, slower delta and slower damped theta components than those of the AEPs. With this technique, we show that the differentiation of sensory and cognitive potentials are not inherent in their overall frequency content but in their frequency components at certain bands. PMID:9711822

Demiralp, T; Ademoglu, A; Istefanopulos, Y; Glr, H O

1998-06-01

280

A High-Frequency Resonant Inverter Topology With Low-Voltage Stress  

E-print Network

This paper presents a new switched-mode resonant inverter, which we term the inverter, that is well suited to operation at very high frequencies and to rapid on/off control. Features of this inverter topology include low ...

Rivas, Juan M.

281

On-chip charge-pump with continuous frequency regulation for precision high-voltage generation  

Microsoft Academic Search

Closed-loop operation of charge-pumps is often taken advantage of in order to improve efficiency and to reduce the charge-pump output impedance and heavy sensitivity to supply and process variations. A fully integrated charge-pump, which utilizes continuous frequency control for the closed-loop operation, is presented in this paper. This means of control allows the charge-pump clock to settle to correct frequency

Lasse Aaltonen; Kari Halonen

2009-01-01

282

Sinusoidal voltage controlled oscillators using operational transconductance amplifiers  

E-print Network

0. 8 0. 6 Nl 0. 4 0. 2 N5 -0. 2 0 12 VI V!M -0. 4 -0. 6 Figure S. S Nonlinear Characteristics of X~, Xs, JVs versus ~vr's V, The effect of the saturation characteristic is shown in Figure 3. 4, where for the fundamental components... 0. 8 0. 6 Nl 0. 4 0. 2 N5 -0. 2 0 12 VI V!M -0. 4 -0. 6 Figure S. S Nonlinear Characteristics of X~, Xs, JVs versus ~vr's V, The effect of the saturation characteristic is shown in Figure 3. 4, where for the fundamental components...

Hoyle Passano, Javier Joaquin

2012-06-07

283

Induction Motor Operation With Non-Sinusoidal Impressed Voltages  

Microsoft Academic Search

The usual procedure in considering the operation of induction motors has been to neglect the effect of harmonics. Although in most instances this gives results which are sufficiently accurate, the question of how much these effects are or how much is being neglected has yet to be answered in electrical engineering literature. In this paper an attempt is made to

L. A. Doggett; E. R. Queer

1929-01-01

284

High-voltage nanosecond pulses in a low-pressure radio-frequency discharge.  

PubMed

An influence of a high-voltage (3-17 kV) 20 ns pulse on a weakly-ionized low-pressure (0.1-10 Pa) capacitively coupled radiofrequency (RF) argon plasma is studied experimentally. The plasma evolution after pulse exhibits two characteristic regimes: a bright flash, occurring within 100 ns after the pulse (when the discharge emission increases by 2-3 orders of magnitude over the steady-state level), and a dark phase, lasting a few hundreds ?s (when the intensity of the discharge emission drops significantly below the steady-state level). The electron density increases during the flash and remains very large at the dark phase. 1D3V particle-in-cell simulations qualitatively reproduce both regimes and allow for detailed analysis of the underlying mechanisms. It is found that the high-voltage nanosecond pulse is capable of removing a significant fraction of plasma electrons out of the discharge gap, and that the flash is the result of the excitation of gas atoms, triggered by residual electrons accelerated in the electric field of immobile bulk ions. The secondary emission from the electrodes due to vacuum UV radiation plays an important role at this stage. High-density plasma generated during the flash provides efficient screening of the RF field (which sustains the steady-state plasma). This leads to the electron cooling and, hence, onset of the dark phase. PMID:23848787

Pustylnik, M Y; Hou, L; Ivlev, A V; Vasilyak, L M; Coudel, L; Thomas, H M; Morfill, G E; Fortov, V E

2013-06-01

285

Design of a pulsewidth-modulated resonant converter for a high-output-voltage power supply  

NASA Astrophysics Data System (ADS)

The design and fabrication of a parallel resonant converter circuit and a high-frequency step-up transformer used to supply an adjustable dc voltage to a load is described. The 500-W system is operated from 115/230 V single-phase 60Hz power, which is rectified and filtered to form a 310-V dc link. A two-transistor half-bridge circuit operating at a fixed frequency above the ciruits resonant frequency converts the dc voltage to an ac voltage at approximately 20 kHx. This high-frequency voltage is transformed with a low-capacitance oil-impregnated ferrite transformer. The output voltage is rectified to form a dc voltage with a maximum value of 90-kV peak. The output voltage is adjustable using pulsewidth modulation of the conduction time of the two transistors in the power circuit. The energy stored in the resonant circuit provides a sinusoidal transformer voltage at fixed frequency over a wide range of control. The system is provided with a closed-loop peak-voltage regulator and an on-off capability from the control electronics. The transformer is designed for a specific value of inductance and capacitance to operate at the desired resonant frequency and characteristic impedance.

Turnbull, Fred G.; Tompkins, Russell E.

1987-12-01

286

Effect of Radio-Frequency and Low-Frequency Bias Voltage on the Formation of Amorphous Carbon Films Deposited by Plasma Enhanced Chemical Vapor Deposition  

NASA Astrophysics Data System (ADS)

The effect of radio-frequency (RF) or low-frequency (LF) bias voltage on the formation of amorphous hydrogenated carbon (a-C:H) films was studied on silicon substrates with a low methane (CH4) concentration (210 vol.%) in CH4+Ar mixtures. The bias substrate was applied either by RF (13.56 MHz) or by LF (150 kHz) power supply. The highest hardness values (~1822 GPa) with lower hydrogen content in the films (~20 at.%) deposited at 10 vol.% CH4, was achieved by using the RF bias. However, the films deposited using the LF bias, under similar RF plasma generation power and CH4 concentration (50 W and 10 vol.%, respectively), displayed lower hardness (~612 GPa) with high hydrogen content (~40 at.%). The structures analyzed by Fourier Transform Infrared (FTIR) and Raman scattering measurements provide an indication of trans-polyacetylene structure formation. However, its excessive formation in the films deposited by the LF bias method is consistent with its higher bonded hydrogen concentration and low level of hardness, as compared to the film prepared by the RF bias method. It was found that the effect of RF bias on the film structure and properties is stronger than the effect of the low-frequency (LF) bias under identical radio-frequency (RF) powered electrode and identical PECVD (plasma enhanced chemical vapor deposition) system configuration.

Hadar, Manis-Levy; Tsachi, Livneh; Ido, Zukerman; Moshe, H. Mintz; Avi, Raveh

2014-10-01

287

Audio Signal Processing Based on Sinusoidal Analysis\\/Synthesis  

Microsoft Academic Search

Based on a sinusoidal model, an analysis\\/synthesis technique is developed that characterizes audio signals, such as speech\\u000a and music, in terms of the amplitudes, frequencies, and phases of the component sine waves. These parameters are estimated\\u000a by applying a peak-picking algorithm to the short-time Fourier transform of the input waveform. Rapid changes in the highly\\u000a resolved spectral components are tracked

T. F. Quatieri; R. J. Mcaulay

288

Frequency-dependent reduction of voltage-gated sodium current modulates retinal ganglion cell response rate to electrical stimulation  

NASA Astrophysics Data System (ADS)

The ability to elicit visual percepts through electrical stimulation of the retina has prompted numerous investigations examining the feasibility of restoring sight to the blind with retinal implants. The therapeutic efficacy of these devices will be strongly influenced by their ability to elicit neural responses that approximate those of normal vision. Retinal ganglion cells (RGCs) can fire spikes at frequencies greater than 200 Hz when driven by light. However, several studies using isolated retinas have found a decline in RGC spiking response rate when these cells were stimulated at greater than 50 Hz. It is possible that the mechanism responsible for this decline also contributes to the frequency-dependent 'fading' of electrically evoked percepts recently reported in human patients. Using whole-cell patch clamp recordings of rabbit RGCs, we investigated the causes for the spiking response depression during direct subretinal stimulation of these cells at 50-200 Hz. The response depression was not caused by inhibition arising from the retinal network but, instead, by a stimulus-frequency-dependent decline of RGC voltage-gated sodium current. Under identical experimental conditions, however, RGCs were able to spike at high frequency when driven by light stimuli and intracellular depolarization. Based on these observations, we demonstrated a technique to prevent the spiking response depression.

Tsai, David; Morley, John W.; Suaning, Gregg J.; Lovell, Nigel H.

2011-10-01

289

SOI Technologies Overview for Low-Power Low-Voltage Radio-Frequency Applications  

Microsoft Academic Search

Thanks to their structure, the SOI technologies present several intrinsic advantages for analog and RF applications. Indeed, as it is well established now, these technologies allow the reduction of the power consumption at a given operating frequency. Moreover, the high-insulating properties of SOI substrates, in particular when high resistivity substrate is used, make that these technologies are perfect candidates for

O. Rozeau; J. Jomaah; S. Haendler; J. Boussey; F. Balestra

2000-01-01

290

A fast technique for frequency tracking of transient process in low-voltage distribution systems  

Microsoft Academic Search

A different technique from the existing techniques is presented in this paper. The technique is developed to use for estimating the frequency of distribution systems both in transient processes of RL circuits and static processes. On the basis of numerical differentiation, 7 sampling points of the sampling sequence are employed for the estimation and computation. The signals with period component

J. K. Wu

2004-01-01

291

Propulsion by sinusoidal locomotion: A motion inspired by Caenorhabditis elegans  

NASA Astrophysics Data System (ADS)

Sinusoidal locomotion is commonly seen in snakes, fish, nematodes, or even the wings of some birds and insects. This doctoral thesis presents the study of sinusoidal locomotion of the nematode C. elegans in experiments and the application of the state-space airloads theory to the theoretical forces of sinusoidal motion. An original MATLAB program has been developed to analyze the video records of C. elegans' movement in different fluids, including Newtonian and non-Newtonian fluids. The experimental and numerical studies of swimming C. elegans has revealed three conclusions. First, though the amplitude and wavelength are varying with time, the motion of swimming C. elegans can still be viewed as sinusoidal locomotion with slips. The average normalized wavelength is a conserved character of the locomotion for both Newtonian and non-Newtonian fluids. Second, fluid viscosity affects the frequency but not the moving speed of C. elegans, while fluid elasticity affects the moving speed but not the frequency. Third, by the resistive force theory, for more elastic fluids the ratio of resistive coefficients becomes smaller. Inspired by the motion of C. elegans and other animals performing sinusoidal motion, we investigated the sinusoidal motion of a thin flexible wing in theory. Given the equation of the motion, we have derived the closed forms of propulsive force, lift and other generalized forces applying on the wing. We also calculated the power required to perform the motion, the power lost due to the shed vortices and the propulsive efficiency. These forces and powers are given as functions of reduced frequency k, dimensionless wavelength z, dimensionless amplitude A/b, and time. Our results show that a positive, time-averaged propulsive force is produced for all k>k0=pi/ z. At k=k0, which implies the moment when the moving speed of the wing is the same as the wave speed of its undulation, the motion reaches a steady state with all forces being zero. If there were no shed vorticity effects, the propulsive force would be zero at z = 0.569 and z = 1.3 for all k, and for a fixed k the wing would gain the optimal propulsive force when z = 0.82. With the effects of shed vorticity, the propulsive efficiency decreases from 1.0 to 0.5 as k goes to infinity, and the propulsive efficiency increases almost in a linear relationship with k0.

Ulrich, Xialing

292

Frequency and temperature dependences of capacitance-voltage characteristics of InGaN/GaN light-emitting structures with multiple quantum wells  

SciTech Connect

A frequency dependence of capacitance-voltage (C-V) characteristics in multiple quantum well InGaN/GaN heterostructures in the range of 60 Hz-5 MHz is investigated at temperatures from 77 to 300 K. It is found that temperature lowering and test frequency increase lead to the similar changes in obtained apparent carrier distributions. It is shown that commonly used conditions for capacitance-voltage profiling of InGaN/GaN LEDs correspond to an intermediate case between low- and high-frequency capacitance approximations. At all temperatures investigated, the edge low-frequency capacitance-voltage profiles are experimentally reached and found to be identical. The process of attainment of equilibrium of the charges in the active region is most likely determined by tunneling of the carriers through the barriers.

Soltanovich, O. A. [Russian Academy of Sciences, Institute of Microelectronic Technology and High-Purity Materials (Russian Federation); Shmidt, N. M. [Russian Academy of Sciences, Ioffe Physical Technical Institute (Russian Federation); Yakimov, E. B., E-mail: yakimov@iptm.ru [Russian Academy of Sciences, Institute of Microelectronic Technology and High-Purity Materials (Russian Federation)

2011-02-15

293

Digitally synthesized high purity, high-voltage radio frequency drive electronics for mass spectrometry.  

PubMed

Reported herein is development of a quadrupole mass spectrometer controller (MSC) with integrated radio frequency (rf) power supply and mass spectrometer drive electronics. Advances have been made in terms of the physical size and power consumption of the MSC, while simultaneously making improvements in frequency stability, total harmonic distortion, and spectral purity. The rf power supply portion of the MSC is based on a series-resonant LC tank, where the capacitive load is the mass spectrometer itself, and the inductor is a solenoid or toroid, with various core materials. The MSC drive electronics is based on a field programmable gate array (FPGA), with serial peripheral interface for analog-to-digital and digital-to-analog converter support, and RS232/RS422 communications interfaces. The MSC offers spectral quality comparable to, or exceeding, that of conventional rf power supplies used in commercially available mass spectrometers; and as well an inherent flexibility, via the FPGA implementation, for a variety of tasks that includes proportional-integral derivative closed-loop feedback and control of rf, rf amplitude, and mass spectrometer sensitivity. Also provided are dc offsets and resonant dipole excitation for mass selective accumulation in applications involving quadrupole ion traps; rf phase locking and phase shifting for external loading of a quadrupole ion trap; and multichannel scaling of acquired mass spectra. The functionality of the MSC is task specific, and is easily modified by simply loading FPGA registers or reprogramming FPGA firmware. PMID:19044454

Schaefer, R T; MacAskill, J A; Mojarradi, M; Chutjian, A; Darrach, M R; Madzunkov, S M; Shortt, B J

2008-09-01

294

Measurement of electron temperatures and electron energy distribution functions in dual frequency capacitively coupled CF4/O2 plasmas using  

E-print Network

source. Many theoretical investigations of 2f-CCP have been car- ried out. Kawamura et al.6 and Turner by ions accelerated in the sheath. Mussenbrock et al.11 developed a nonlinear global zero-dimensional model of a 2f-CCP driven by the superposition of two sinusoidal radio-frequency rf voltages. They found

Economou, Demetre J.

295

A Voltage Controlled Oscillator for a Phase-Locked Loop Frequency Synthesizer in a Silicon-on-Sapphire Process  

SciTech Connect

Engineers from a government-owned engineering and manufacturing facility were contracted by government-owned research laboratory to design and build an S-band telemetry transmitter using Radio Frequency Integrated Circuit (RFIC) technology packaged in a Low-Temperature Co-fired Ceramic (LTCC) Multi-Chip Module. The integrated circuit technology chosen for the Phase-Locked Loop Frequency Synthesizer portion of the telemetry transmitter was a 0.25 um CMOS process that utilizes a sapphire substrate and is fabricated by Peregrine Semiconductor corporation. This thesis work details the design of the Voltage Controlled Oscillator (VCO) portion of the PLL frequency synthesizer and constitutes an fully integrated VCO core circuit and a high-isolation buffer amplifier. The high-isolation buffer amplifier was designed to provide 16 dB of gain for 2200-3495 MHz as well as 60 dB of isolation for the oscillator core to provide immunity to frequency pulling due to RF load mismatch. Actual measurements of the amplifier gain and isolation showed the gain was approximately 5 dB lower than the simulated gain when all bond-wire and test substrate parasitics were taken into account. The isolation measurements were shown to be 28 dB at the high end of the frequency band but the measurement was more than likely compromised due to the aforementioned bond-wire and test substrate parasitics. The S-band oscillator discussed in this work was designed to operate over a frequency range of 2200 to 2300 MHz with a minimum output power of 0 dBm with a phase-noise of -92 dBc/Hz at a 100 kHz offset from the carrier. The tuning range was measured to be from 2215 MHz to 2330 MHz with a minimum output power of -7 dBm over the measured frequency range. A phase-noise of -90 dBc was measured at a 100 kHz offset from the carrier.

Garrison, Sean

2009-05-21

296

Human stance on a sinusoidally translating platform: balance control by feedforward and feedback mechanisms  

Microsoft Academic Search

With subjects standing on a treadmill moving sinusoidally backward and forward, recordings of electromyographic (EMG) leg and trunk muscle activity, head and joint movements and platform torque were made with the subjects' eyes open or closed. The sinusoidal frequency was changed, stepwise and randomly, between 0.5, 0.3 and 0.25 Hz. The amplitude of the deflection was constant at 12 cm.

V. Dietz; M. Trippel; I. K. Ibrahim; W. Berger

1993-01-01

297

I Found Sinusoids in My Gas Bill.  

ERIC Educational Resources Information Center

Uses the average-monthly-temperature function as an application of the sine wave. Argues that the attractive aspect of gas bill graphs is that they clearly illustrate that sinusoidal curves are useful and meaningful in an everyday context. (ASK)

Schloemer, Cathy G.

2000-01-01

298

Indirect current control of a unity power factor sinusoidal current boost type three-phase rectifier  

Microsoft Academic Search

The indirect current control scheme has evolved from the success of the hysteresis current controlled voltage regulated rectifier, which has been shown to be capable of: unity and even leading power factor operation; near sinusoidal current waveforms; and bilateral power transfer without the need of bi-directional solid state power switches. The advance consists of replacing the inner hysteresis current feedback

J. W. Dixon; Boon-Teck Ooi

1988-01-01

299

Sinusoidal Response of dc SQUIDs (Superconducting Quantum Interference Devices) for rf Power Measurements.  

National Technical Information Service (NTIS)

Current, power, and attenuation measurements with rf SQUIDs are based on the fact that the voltage from the microwave readout circuit can be made a nearly sinusoidal function of the magnetic flux threading the SQUID. The authors point out here that an asy...

R. L. Peterson

1987-01-01

300

One-dimensional plasma photonic crystals with sinusoidal densities  

NASA Astrophysics Data System (ADS)

Properties of electromagnetic waves with normal and oblique incidence have been studied for one-dimensional plasma layers with sinusoidal densities. Wave transmittance as a function of wave frequency exhibits photonic band gaps characteristic of photonic crystals. For periodic structures, increasing collision frequency is demonstrated to lead to greater absorption, increasing the modulation factor enlarges the gap width, and increasing incidence angle can change the gap locations of the two polarizations. If a defect layer is introduced by inserting a new plasma layer in the center, a defect mode may appear within the gap. Periodic number, collision frequency, and modulation factor can affect magnitude of the defect mode. The incidence angle enables the frequency to be tuned. Defect layer thickness affects both frequency and number of defect modes. These results may provide theoretical guidance in designing tunable narrow-band filters.

Qi, L.; Shang, L.; Zhang, S.

2014-01-01

301

Performance evaluation of half-bridge cascaded multilevel converters operated with multicarrier sinusoidal PWM techniques  

Microsoft Academic Search

High-power high-voltage power electronics systems with fully-controlled semiconductors can benefit from the development of modular solutions based on voltage-sourced building blocks. This paper offers a performance comparison of various multicarrier sinusoidal pulse width modulation (PWM) techniques for the control of the modular multilevel converter (MMC) based on the half-bridge capacitor cell. It is found that the PWM method can significantly

Georgios S. Konstantinou; Vassilios G. Agelidis

2009-01-01

302

Sensorless Sinusoidal Wave Drive for Control of Power Factor of PM Motor by Detection of Inverter Bus Current  

NASA Astrophysics Data System (ADS)

Permanent-magnet synchronous motors (PMSMs) with a sinusoidal back EMF are widely used in domestic appliances for reduction of acoustic noises and energy consumption. PMSMs are generally controlled with a sinusoidal waveform current. Typically, PMSMs are controlled by vector-controlled sinusoidal drives, which require powerful computational resources. Hence, simpler sinusoidal wave drives such as V/f drives, which control the phase difference between the voltage and the current (power factor of PM Motor) have been proposed for controlling PMSMs. This paper presents a new method that does not require current sensors but can be used to estimate the phase difference by sampling the voltage of the shunt register, which is used to detect the over current supplied to the inverter. This method enables detection of current and accurate estimation and appropriate control of the phase difference. Using this method, we could control the phase difference and achieve high efficiency, cost reduction, and high reliability.

Matsushita, Motoshi; Kameyama, Hiroyuki; Ikeboh, Yasuhiro; Morimoto, Shigeo

303

Voltage transformer frequency response. Measuring harmonics in Norwegian 300 kV and 132 kV power systems  

Microsoft Academic Search

Measuring harmonics in high voltage power systems with inductive and in particular capacitive voltage transformers, CVTs, may cause large errors. Test carried out by The Norwegian National Grid Company (Statnett), Bergenshalvoens Kommunale Kraftselskap (BKK) and The Norwegian Electric Power Research Institute (now SINTEF Energy Research) revealed errors from 80% to +1200% (0,2-12 pu) of correct values. Inductive voltage transformers did

H. Seljeseth; E. A. Saethre; T. Ohnstad; I. Lien

1998-01-01

304

Northeast Corridor Improvement Project Task 204: Electric Multiple-Unit Car and Locomotive Conversion for Dual-Voltage, Dual-Frequency Operation.  

National Technical Information Service (NTIS)

The report covers engineering requirements of converting electric MU cars and locomotives operating on the Northeast Corridor for dual-voltage, dual-frequency operation during and after rehabilitation of the electrification system for 25 kV, 60 Hz power. ...

1977-01-01

305

Detecting postural responses to sinusoidal sensory inputs: a statistical approach  

PubMed Central

A common way for understanding sensory integration in postural control is to provide sinusoidal perturbations to the sensory systems involved in balance. However, not all subjects exhibit a response to the perturbation. Determining whether or not a response has occurred is usually done qualitatively, e.g. by visual inspection of the power spectrum. In this paper we present the application of a statistical test for quantifying whether or not a postural sway response is present. The test uses an F-statistic for determining if there is significant power in postural sway data at the stimulus frequency. In order to describe the application of this method, twenty subjects viewed sinusoidal anterior-posterior optic flow at 0.1 and 0.25 Hz. while their anterior-posterior head translation was measured. The test showed that significant postural responses were detected at the stimulus frequency in 12/20 subjects at 0.1 Hz and 13/20 subjects at 0.25 Hz. PMID:15473199

Sparto, Patrick J.; Jasko, Jeffrey G.; Loughlin, Patrick J.

2014-01-01

306

Generalized frequency modulation  

E-print Network

In frequency modulation (FM) systems, a continuous-time information signal is modulated onto a sinusoidal carrier wave by using the information signal to modulate the frequency of the carrier wave. In this thesis, a more ...

Torres, Wade Patrick

2001-01-01

307

Fine-Grained Dynamic Voltage and Frequency Scaling for Precise Energy and Performance Trade-Off Based on the Ratio of Off-Chip Access to On-Chip Computation Times  

Microsoft Academic Search

This paper presents an intra-process dynamic voltage and frequency scaling (DVFS) technique targeted toward non real-time applications running on an embedded system platform. The key idea is to make use of runtime information about the external memory access statistics in order to perform CPU voltage and frequency scaling with the goal of minimizing the energy consumption while translucently controlling the

Kihwan Choi; Ramakrishna Soma; Massoud Pedram

2004-01-01

308

Analysis of a modular generator for high-voltage, high-frequency pulsed applications, using low voltage semiconductors (< 1 kV) and series connected step-up (1:10) transformers.  

PubMed

This article discusses the operation of a modular generator topology, which has been developed for high-frequency (kHz), high-voltage (kV) pulsed applications. The proposed generator uses individual modules, each one consisting of a pulse circuit based on a modified forward converter, which takes advantage of the required low duty cycle to operate with a low voltage clamp reset circuit for the step-up transformer. This reduces the maximum voltage on the semiconductor devices of both primary and secondary transformer sides. The secondary winding of each step-up transformer is series connected, delivering a fraction of the total voltage. Each individual pulsed module is supplied via an isolation transformer. The assembled modular laboratorial prototype, with three 5 kV modules, 800 V semiconductor switches, and 1:10 step-up transformers, has 80% efficiency, and is capable of delivering, into resistive loads, -15 kV1 A pulses with 5 micros width, 10 kHz repetition rate, with less than 1 micros pulse rise time. Experimental results for resistive loads are presented and discussed. PMID:17411205

Redondo, L M; Fernando Silva, J; Margato, E

2007-03-01

309

High voltage power supply  

NASA Technical Reports Server (NTRS)

A high voltage power supply is formed by three discrete circuits energized by a battery to provide a plurality of concurrent output signals floating at a high output voltage on the order of several tens of kilovolts. In the first two circuits, the regulator stages are pulse width modulated and include adjustable ressistances for varying the duty cycles of pulse trains provided to corresponding oscillator stages while the third regulator stage includes an adjustable resistance for varying the amplitude of a steady signal provided to a third oscillator stage. In the first circuit, the oscillator, formed by a constant current drive network and a tuned resonant network included a step up transformer, is coupled to a second step up transformer which, in turn, supplies an amplified sinusoidal signal to a parallel pair of complementary poled rectifying, voltage multiplier stages to generate the high output voltage.

Ruitberg, A. P.; Young, K. M. (inventors)

1985-01-01

310

Rectification of confined diffusion driven by a sinusoidal force.  

PubMed

A particle diffusing in an asymmetric periodic channel, driven by a sinusoidal force F(t)=F0cos?t (the rocking ratchet) is considered. The asymptotic solution of the generalized Fick-Jacobs equation describing the system is studied in the nonadiabatic regime. The leading term of the rectified current, appearing in the order ?F02, is derived. The method presented enables us to solve the problem analytically for a sawtooth channel and also to look for approximative formulas applicable in a wide range of frequencies ?. Even the simplest approximation qualitatively reproduces the current reversal at higher frequencies as the result of growing phase lag of the rocking density behind the driving force. PMID:24827209

Kalinay, Pavol

2014-04-01

311

Connecting Renewables Directly to the Grid: Resilient Multi-Terminal HVDC Networks with High-Voltage High-Frequency Electronics  

SciTech Connect

GENI Project: GE is developing electricity transmission hardware that could connect distributed renewable energy sources, like wind farms, directly to the grideliminating the need to feed the energy generated through intermediate power conversion stations before they enter the grid. GE is using the advanced semiconductor material silicon carbide (SiC) to conduct electricity through its transmission hardware because SiC can operate at higher voltage levels than semiconductors made out of other materials. This high-voltage capability is important because electricity must be converted to high-voltage levels before it can be sent along the grids network of transmission lines. Power companies do this because less electricity is lost along the lines when the voltage is high.

None

2012-01-23

312

Singleloop voltage and frequency control of stand-alone three-phase four-wire renewable energy conversion system with battery storage  

Microsoft Academic Search

In this paper, single control loop based scheme for regulation of voltage and frequency of Self Excited Induction Generator (SEIG) based stand-alone 3-phase 4-wire renewable energy conversion system under source and balanced\\/unbalanced load perturbations is presented. The regulation is accomplished by maintaining reactive and active power balance across individual phases of SEIG using a Generalized Impedance Controller (GIC). GIC is

J. K. Chatterjee; Priyesh J. Chauhan

2011-01-01

313

Characteristics of 10 kV SiC MOSFET and PIN Diode and Their Application Prospect in High Voltage High Frequency DC\\/DC Converter  

Microsoft Academic Search

10 kV power 4H-SiC DiMOSFET and PIN diodes are currently under development by a number of organizations in the United States with the aim to enable their application in high voltage high frequency power conversion applications. The aim of this study is to obtain key device characteristics of these devices through device simulation so that realistic application prospect of these

Jun Wang; Liyu Yang; Tiefu Zhao; Alex Q. Huang

2007-01-01

314

A 52.4mW 3D Graphics Processor with 141Mvertices\\/s Vertex Shader and 3 Power Domains of Dynamic Voltage and Frequency Scaling  

Microsoft Academic Search

A 3D graphics processor fabricated using 0.18mum 6M CMOS contains 1.57M transistors and 29kB SRAM in a core size of 17.2mm2. The vertex shader utilizes a logarithmic number system for 141 Mvertices\\/s and the 3 power domains are controlled separately by dynamic voltage and frequency scaling for 52.4mW at 60fps.

Byeong-Gyu Nam; Jeabin Lee; Kwanho Kim; Seung Jin Lee; Hoi-Jun Yoo

2007-01-01

315

A Sub1-V 4GHz CMOS VCO and a 12.5GHz oscillator for low-voltage and high-frequency applications  

Microsoft Academic Search

This paper presents the design and experimental measurements of four CMOS LC-based oscillators. The design methodologies of two different topologies and approaches for their optimization are presented. The first topology is optimized for low voltage operation in a 0.25-?m process, which is demonstrated by a finest prototype, requiring only a 0.85-V power supply and reaching a maximum frequency of 4

Ahmed H. Mostafa; Mourad N. El-Gamal; Ramez A. Rafla

2001-01-01

316

Human comfort in relation to sinusoidal vibration  

NASA Technical Reports Server (NTRS)

An investigation was made to assess the overall subjective comfort levels to sinusoidal excitations over the range 1 to 19 Hz using a two axis electrohydraulic vibration simulator. Exposure durations of 16 minutes, 25 minutes, 1 hour, and 2.5 hours have been considered. Subjects were not exposed over such durations, but were instructed to estimate the overall comfort levels preferred had they been constantly subjected to vibration over such durations.

Jones, B.; Rao, B. K. N.

1975-01-01

317

Detecting the Position of Nonlinear Component in Periodic Structures from the System Responses to Dual Sinusoidal Excitations  

Microsoft Academic Search

Based on the Nonlinear Output Frequency Response Functions (NOFRFs), a novel method is developed to detect the position of nonlinear components in periodic structures. The detection procedure requires exciting the nonlinear systems twice using two sinusoidal inputs separately. The frequencies of the two inputs are different; one frequency is twice as high as the other one. The validity of this

Z. K. Peng; Z. Q. Lang

318

Matrix pencil method for estimating parameters of exponentially damped\\/undamped sinusoids in noise  

Microsoft Academic Search

A study of a matrix pencil method for estimating frequencies and damping factors of exponentially damped and\\/or undamped sinusoids in noise is presented. Comparison of this method to a polynomial method (SVD-Prony method) shows that the matrix pencil method and the polynomial method are two special cases of a matrix prediction approach and that the pencil method is more efficient

Y. Hua; T. K. Sarkar

1990-01-01

319

PARSHL: An Analysis/Synthesis Program for Non-Harmonic Sounds Based on a Sinusoidal Representation  

E-print Network

. With these techniques, the signal is modeled as a sum of sine waves, and the parameters to be determined by analysis are the slowly time-varying amplitude and frequency for each sine wave. In the following subsections, wePARSHL: An Analysis/Synthesis Program for Non-Harmonic Sounds Based on a Sinusoidal Representation

Smith III, Julius Orion

320

The sinusoid as the longitudinal profile in backward-wave oscillators of large  

E-print Network

solution is represented by a single expansion of TM eigenmodes. From the dispersion diagrams thus obtained-circles + rectangles) sinusoidal profile light line beam line TM01-mode dispersion diagram corresponding diagram showing the first passband #12;6 TM01-mode upper cutoff frequencies (-point) as function

321

Detection of Binary Pulsars with GPU-Accelerated Sinusoidal Hough Transformations  

NASA Astrophysics Data System (ADS)

Analysis of relativistic binary pulsars is currently the best means by which to test theories of gravity in strong gravitational fields. Four-dimensional Hough Transformations can detect sinusoids in noisy images. Hough Transformations can be applied to Dynamic Power Spectra to detect the sinusoidal shift in observed spin frequency from binary pulsars in approximately circular orbits. We present four alternative GPU implementations of a Hough Transformation algorithm, which we apply to synthesized Dynamic Power Spectra data to determine the GPU kernel that provides the best acceleration.

Laidler, C.; Kuttel, M. M.

2013-10-01

322

The effect of a sinusoidal wavefront on the transfer function of a circular aperture.  

PubMed

The influence of a radially symmetric sinusoidal aberration function on the behavior of the transfer function is studied. It is shown that the main effect of the sinusoidal wavefront is manifest in the low frequency region of the transfer function with a rapid drop in contrast. The transfer function is computed via the sampling theorem for some typical situations. Finally, it is shown that when the wavefront is crinkly there is no coupling between the superposed wavefront and the wavefront owing to the natural aberrations of the optical system. PMID:20057638

Barakat, R; Houston, A

1966-11-01

323

Sinusoidal galvanic vestibular stimulation (sGVS) induces a vasovagal response in the rat  

Microsoft Academic Search

Blood pressure (BP) and heart rate (HR) were studied in isoflurane-anesthetized Long-Evans rats during sinusoidal galvanic\\u000a vestibular stimulation (sGVS) and sinusoidal oscillation in pitch to characterize vestibular influences on autonomic control\\u000a of BP and HR. sGVS was delivered binaurally via Ag\\/AgCl needle electrodes inserted over the mastoids at stimulus frequencies\\u000a 0.0080.4Hz. Two processes affecting BP and HR were induced by

Bernard Cohen; Giorgio P. Martinelli; Dmitri Ogorodnikov; Yongqing Xiang; Theodore Raphan; Gay R. Holstein; Sergei B. Yakushin

2011-01-01

324

1072 JOURNAL OF MICROELECTROMECHANICAL SYSTEMS, VOL. 17, NO. 5, OCTOBER 2008 Voltage Control of the Resonance Frequency of  

E-print Network

, dielectric elastomer actuator, dielectric electroactive actuator (DEA), dielectric electroactive polymer of the Resonance Frequency of Dielectric Electroactive Polymer (DEAP) Membranes Philippe Dubois, Samuel Rosset on the characterization, active tuning, and modeling of the first mode resonance frequency of dielectric electroactive

Floreano, Dario

325

AlGaN/GaN-HEMTs with a breakdown voltage higher than 100 V and maximum oscillation frequency f{sub max} as high as 100 GHz  

SciTech Connect

The N-Al{sub 0.27}Ga{sub 0.73}N/GaN High Electron Mobility Transistors (HEMTs) with different gate lengths L{sub g} (ranging from 170 nm to 0.5 {mu}m) and gate widths W{sub s} (ranging from 100 to 1200 {mu}m) have been studied. The S parameters have been measured; these parameters have been used to determine the current-gain cutoff frequency f{sub t}, the maximum oscillation frequency f{sub max}, and the power gain MSG/MAG and Mason's coefficients were investigated in the frequency range from 10 MHz to 67 GHz in relation to the gate length and gate width. It was found that the frequencies f{sub t} and f{sub max} attain their maximum values of f{sub t} = 48 GHz and f{sub max} = 100 GHz at L{sub g} = 170 nm and W{sub g} = 100 {mu}m. The optimum values of W{sub g} and output power P out of the basic transistors have been determined for different frequencies of operation. It has also been demonstrated that the 170 nm Al{sub 0.27}Ga{sub 0.73}N/GaN HEMT technology provides both good frequency characteristics and high breakdown voltages and is very promising for high-frequency applications (up to 40 GHz)

Mokerov, V. G., E-mail: vgmokerov@yandex.ru; Kuznetsov, A. L.; Fedorov, Yu. V.; Bugaev, A. S.; Pavlov, A. Yu.; Enyushkina, E. N.; Gnatyuk, D. L.; Zuev, A. V.; Galiev, R. R.; Ovcharenko, E. N. [Russian Academy of Sciences, Institute of UHF Semiconductor Electronics (Russian Federation); Sveshnikov, Yu. N. [Elma-Malahit-Concern Energomera (Russian Federation); Tsatsulnikov, A. F.; Ustinov, V. M. [Russian Academy of Sciences, St. Petersburg Physics and Technology Centre for Research and Education (Russian Federation)

2009-04-15

326

The inhibition of stuttering via the presentation of natural speech and sinusoidal speech analogs.  

PubMed

Sensory signals containing speech or gestural (articulatory) information (e.g., choral speech) have repeatedly been found to be highly effective inhibitors of stuttering. Sine wave analogs of speech consist of a trio of changing pure tones representative of formant frequencies. They are otherwise devoid of traditional speech cues, yet have proven to evoke consistent linguistic percepts in listeners. Thus, we investigated the potency of sinusoidal speech for inhibiting stuttering. Ten adults who stutter read while listening to (a) forward-flowing natural speech; (b) forward-flowing sinusoid analogs of natural speech; (c) reversed natural speech; (d) reversed sinusoid analogs of natural speech; and (e) a continuous 1000 Hz pure tone. The levels of stuttering inhibition achieved using the sinusoidal stimuli were potent and not significantly different from those achieved using natural speech (approximately 50% in forward conditions and approximately 25% in the reversed conditions), suggesting that the patterns of undulating pure tones are sufficient to endow sinusoidal sentences with 'quasi-gestural' qualities. These data highlight the sensitivity of a specialized 'phonetic module' for extracting gestural information from sensory stimuli. Stuttering inhibition is thought to occur when perceived gestural information facilitates fluent productions via the engagement of mirror neurons (e.g., in Broca's area), which appear to play a crucial role in our ability to perceive and produce speech. PMID:16806702

Saltuklaroglu, Tim; Kalinowski, Joseph

2006-08-14

327

The application of all-pass filters in the design of multiphase sinusoidal systems  

Microsoft Academic Search

The design of even and odd phase sinusoidal systems using all-pass networks is presented. The all-pass network has the unique characteristic of unity gain at all frequencies and a frequency-dependent phase relationship between output and input. It produces up to 180 phase shift which allows the easy implementation of multiphase systems. The network is implemented using the widely available operational

S. J. G Gift

2000-01-01

328

Response of a radial-bladed centrifugal pump to sinusoidal disturbances for noncavitating flow  

NASA Technical Reports Server (NTRS)

A radial-bladed centrifugal pump was run in water with sinusoidal fluctuations of pressure and flow rate imposed at the pump inlet. Since the flow was noncavitating, zero gain was assumed in computing pump impedance. The inertive reactance became greater than the resistance at relatively low frequencies. An electric circuit model was developed in order to explain the trends of inertance and resistance with frequency.

Anderson, D. A.; Blade, R. J.; Stevans, W.

1971-01-01

329

Voltage, frequency, and phase-difference angle control of PWM inverters-fed two-phase induction motors  

Microsoft Academic Search

A phase-difference angle (PDA) controlled pulsewidth-modulated (PWM) inverter is proposed for a two-phase induction motor adjustable speed drive. Output waveforms are fixed over the whole operating range of the motor. The motor torque is controlled not by the modulation of the phase voltage, but by the PDA. Based on the selected harmonic elimination (SHE) PWM technique, the commutation angles of

Do-Hyun Jang; Jong-Soo Won

1994-01-01

330

Spur-reduced digital sinusoid synthesis  

NASA Technical Reports Server (NTRS)

This article presents and analyzes a technique for reducing the spurious signal content in digital sinusoid synthesis. Spurious-harmonic (spur) reduction is accomplished through dithering both amplitude and phase values prior to word-length reduction. The analytical approach developed for analog quantization is used to produce new bounds on spur performance in these dithered systems. Amplitude dithering allows output word-length reduction without introducing additional spurs. Effects of periodic dither similar to those produced by a pseudonoise (PN) generator are analyzed. This phase-dithering method provides a spur reduction of 6(M plus one) dB per phase bit when the dither consists of M uniform variates. While the spur reduction is at the expense of an increase in system noise, the noise power can be made white, making the power spectral density small. This technique permits the use of a smaller number of phase bits addressing sinusoid lookup tables, resulting in an exponential decrease in system complexity. Amplitude dithering allows the use of less complicated multipliers and narrower data paths in purely digital applications, as well as the use of coarse resolution, highly linear digital to analog converters (DAC's) to obtain spur performance limited by the DAC linearity rather than its resolution.

Flanagan, M. J.; Zimmerman, G. A.

1993-01-01

331

High-Efficient High Frequency Linked Zero Voltage Soft Switching PWM DC/DC Power Converter with ON/OFF-Assisted Synchronous Rectifier Scheme  

NASA Astrophysics Data System (ADS)

Advanced development of the high frequency pulse modulated DC/DC power converters are indispensable in order to achieve smaller size, higher performances of the power supplies. In resent years the problems of the electromagnetic noise generation caused by the hard-switching pulse width modulation (PWM)based high frequency operation of the switching power devices have been significant, including switching losses and switching surges. As result a variety of soft-switching power conversion circuit technologies have been attracted special interests for reducing switching power losses and minimizing electromagnetic interference. The soft-switching pulse modulation of DC/DC power circuit topologies can be divided into continuous current mode resonant type and quasi-resonant voltage mode type. The soft-switching DC/DC converters, a continuous current mode zero current soft-switching (ZCS) DC/DC converter with pulse frequency modulation (PFM) has been already put into a practical use. In this sort of power converters soft-switching commutation can be achieved over wide load variation ranges and high stability can be also performed, but high current peak stress through power semiconductor devices arises, however, and it causes relatively large increase of conduction power losses in the power semiconductor devices, high frequency transformers as well as rectifier diodes. As a result, the problem of a high efficiency for DC/DC power converter could not still unsolved. Thereupon, in this paper, quasi-resonant voltage mode based soft-switching PWM DC/DC power converter with a high frequency transformer link is presented, which has on/off assisted synchronous rectifier in its secondary side. The PWM operation of this converter is described in comparison with conventional one. Due to using power MOSFET as on/off assisted synchronous rectifier in the secondary side of the high frequency isolated transformer, it is possible to achieve stable zero voltage soft-switching (ZVS) conditions from no load to the rated load for minimum requirement of a magnetizing current. As result of a high value of the magnetizing inductance design, the power converter actual efficiency of this converter can be designed so as to above 97% in experiment. Moreover, results of a switching losses analysis are discussed from an experimental point of views in this paper. The effectiveness of the power converter treated hare is proved from a practical point of view by using 32kHz-2.5kW breadboard setup.

Sato, Shinji; Moisseev, Serguei; Ishitobi, Manabu; Hiraki, Eiji; Nakaoka, Mutsuo

332

Optical voltage reference  

SciTech Connect

An optical voltage reference for providing an alternative to a battery source. The optical reference apparatus provides a temperature stable, high precision, isolated voltage reference through the use of optical isolation techniques to eliminate current and impedance coupling errors. Pulse rate frequency modulation is employed to eliminate errors in the optical transmission link while phase-lock feedback is employed to stabilize the frequency to voltage transfer function.

Rankin, R.; Kotter, D.

1992-12-31

333

Optical voltage reference  

DOEpatents

An optical voltage reference for providing an alternative to a battery source is described. The optical reference apparatus provides a temperature stable, high precision, isolated voltage reference through the use of optical isolation techniques to eliminate current and impedance coupling errors. Pulse rate frequency modulation is employed to eliminate errors in the optical transmission link while phase-lock feedback is employed to stabilize the frequency to voltage transfer function. 2 figures.

Rankin, R.; Kotter, D.

1994-04-26

334

Optical voltage reference  

DOEpatents

An optical voltage reference for providing an alternative to a battery source. The optical reference apparatus provides a temperature stable, high precision, isolated voltage reference through the use of optical isolation techniques to eliminate current and impedance coupling errors. Pulse rate frequency modulation is employed to eliminate errors in the optical transmission link while phase-lock feedback is employed to stabilize the frequency to voltage transfer function.

Rankin, Richard (Ammon, ID); Kotter, Dale (Bingham County, ID)

1994-01-01

335

Fine-grained dynamic voltage and frequency scaling for precise energy and performance tradeoff based on the ratio of off-chip access to on-chip computation times  

Microsoft Academic Search

Abstract This paper ,presents ,an intra-process,dynamic ,voltage ,and frequency,scaling (DVFS) technique targeted toward,non real-time applications running on an embedded,system platform. The key idea isto make ,use of runtime ,information ,about the external memory access statistics in order ,to perform ,CPU voltage and ,frequency scaling with the goal of minimizing ,the energy ,consumption ,while translucently controlling the performance ,penalty. The proposed

Kihwan Choi; Ramakrishna Soma; Massoud Pedram

2005-01-01

336

Parametric Estimation of Harmonically Related Sinusoids  

E-print Network

algorithm proves quite robust and successfully tracks both stationary and slowly varying frequency signals. Later, we propose an algorithm for fundamental frequency estimation which relies on the initial harmonic frequency estimate. The results of tests...

Dixit, Richa

2010-04-01

337

Response of the normal human ankle joint to imposed sinusoidal movements.  

PubMed Central

Ankle joints were subjected to sinusoidal movements at a range of amplitudes and frequencies. Records were made of electromyograms (e.m.g.s) in calf muscles, and of the forces at the joints. When the leg is relaxed, the ankle joint resists an imposed sinusoidal movement with a small approximately sinusoidal force. It is stiffer in its resistance to small movements than to large ones, and this resistance is greater when the joint is dorsiflexed than when it is plantarflexed. If the subject exerts a steady mean flexing force, the imposed sinusoidal movement generates reflex activity which may be recorded as a modulation of the gastrocnemius and soleus e.m.g.s. The e.m.g. response to the sinusoidal movement occurs later in cycles of movement at high than at low frequencies, as one could expect of a reflex pathway that involves a delay. The results suggest that this delay is between 50 and 60 ms, and we conclude that under these circumstances spinal stretch reflexes are playing the important part. The relation of the resisting force to the movement has been displayed as a vector. As the frequency changes, this vector describes the circular path that is characteristic of a system which includes delays or lags; this path enables one to draw conclusions about the amplitude and timing of the reflex resistance to the movement. When a subject exerts a moderate flexing force against the sinusoidal movement for some minutes, the reflex response becomes progressively potentiated. A subject whose reflex responses are normally slight may then exhibit a vigorous reflex response to the movement of that ankle. This enhancement of spinal reflex activity was accompanied by an increase in the myotatic reflex response at the ankle. Reflex responses to sinusoidal movement were most clearly seen when the subject exerted a mean flexing force that amounted to about one-fifth of his maximum. Very small movements (+/- 0.5 degrees) generated little or no reflex response. With large amplitudes of movement there was more reflex activity, but at some amplitude (which varied from subject to subject and from time to time) the reflex mechanism appeared to 'saturate', and further increases in amplitude were not accompanied by comparable increases in the reflex response. With movements at 10-15 Hz the e.m.g. response often became large in alternate cycles, with less activity in the intervening cycles.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:6655591

Evans, C M; Fellows, S J; Rack, P M; Ross, H F; Walters, D K

1983-01-01

338

Combined effect of constant high voltage electrostatic field and variable frequency pulsed electromagnetic field on the morphology of calcium carbonate scale in circulating cooling water systems.  

PubMed

Research on scale inhibition is of importance to improve the heat transfer efficiency of heat exchangers. The combined effect of high voltage electrostatic and variable frequency pulsed electromagnetic fields on calcium carbonate precipitation was investigated, both theoretically and experimentally. Using energy dispersive spectrum analysis, the predominant phase was found to be CaCO(3). The formed crystal phases mainly consist of calcite and aragonite, which is, in part, verified by theory. The results indicate that the setting of water flow velocity, and high voltage electrostatic and variable frequency pulsed electromagnetic fields is very important. Favorable values of these parameters can have a significant anti-scaling effect, with 68.95% of anti-scaling ratio for scale sample 13, while unfavorable values do not affect scale inhibition, but rather promoted fouling, such as scale sample 6. By using scanning electron microscopy analysis, when the anti-scaling ratio is positive, the particle size of scale was found to become smaller than that of untreated sample and the morphology became loose. The X-ray diffraction results verify that the good combined effect favors the appearance and growth of aragonite and restrains its transition to calcite. The mechanism for scale reduction is discussed. PMID:25259497

Zhao, Ju-Dong; Liu, Zhi-An; Zhao, Er-Jun

2014-01-01

339

A digital frequency synthesizer  

Microsoft Academic Search

A digital frequency synthesizer has been designed and constructed based on generating digital samples ofexp [j(2^{pi}nk\\/N)]at timenT. The real and imaginary parts of this exponential form samples of quadrature sinusoids where the frequency indexkis allowed to vary(-N\\/4) leq K < (N\\/4). The digital samples drive digital to analog converters followed by low-pass interpolating filters to produce analog sinusoids. The method

JOSEPH TIERNEY; CHARLES M. RADER; B. Gold

1971-01-01

340

Potential damage to DC superconducting magnets due to the high frequency electromagnetic waves  

NASA Technical Reports Server (NTRS)

Experimental data are presented in support of the hypothesis that a dc superconducting magnet coil does not behave strictly as an inductor, but as a complicated electrodynamic device capable of supporting electromagnetic waves. Travel times of nanosecond pulses and evidence of sinusoidal standing waves were observed on a prototype four-layer solenoidal coil at room temperature. Ringing observed during switching transients appears as a sequence of multiple reflected square pulses whose durations are related to the layer lengths. With sinusoidal excitation of the coil, the voltage amplitude between a pair of points on the coil exhibits maxima at those frequencies such that the distance between these points is an odd multiple of half wavelength in free space. Evidence indicates that any disturbance, such as that resulting from switching or sudden fault, initiates multiple reflections between layers, thus raising the possibility for sufficiently high voltages to cause breakdown.

Gabriel, G. J.

1977-01-01

341

Derivation of Mathematical Expressions to Define Resonant Ejection from Square and Sinusoidal Wave Ion Traps  

SciTech Connect

The use of resonant ejection for mass analysis with ion traps is increasing primarily because it markedly improves the mass range and resolution of ion traps. Unfortunately, an easy-to-use analytical expression that defines the ejection mass as a function of the trapping and excitation frequencies is missing in the literature because the secular frequency of the ions in sinusoidal ion traps is not easily determined for all stable values of qz from the Mathieu equation. However, the ion secular frequency for all stable values of qz in digital ion traps can be readily determined from Hill s equation. We have taken this expression and solved it for qz to produce an analytical expression for the ejection mass as a function of trapping and excitation frequency. We also recognized that the expression for the ion mass during resonant ejection for a square wave driven trap can be converted to an expression for a sinusoidal wave trap merely by multiplication by a factor of 4/ . These new expressions open up the possibility of rapid mass calibration for any method of resonant ejection from square or sinusoidal wave driven ion traps.

Koizumi, Hideya [ORNL; Whitten, William B [ORNL; Reilly, Pete [ORNL; KoizumiPh.D., Eiko [Peace College

2009-01-01

342

A Voltage Controlled Oscillator for a Phase-Locked Loop Frequency Synthesizer in a Silicon-on-Sapphire Process  

E-print Network

.5: Typical single-sideband phase-noise with null null/null null corner frequency highlighted ...........................................................................................43 Figure 3.6: Differentially cross-coupled oscillator core... layer that is used for creating high-Q passive components such as inductors and metal-insulator-metal (MIM) capacitors. The sapphire substrate?s high resistivity has several distinct advantages when compared to a bulk silicon substrate...

Garrison, Sean Michael

2009-05-22

343

An Accurate, Low-Voltage, CMOS Switching Power Supply With Adaptive On-Time Pulse-Frequency Modulation (PFM) Control  

Microsoft Academic Search

Integrated switching power supplies with multimode control are gaining popularity in state-of-the-art portable applications like cellular phones, personal digital assistants (PDAs), etc., because of their ability to adapt to various loading conditions and therefore achieve high efficiency over a wide load-current range, which is critical for extended battery life. Constant-frequency, pulsewidth modulated (PWM) switching converters, for instance, have poor light-load

Biranchinath Sahu; Gabriel A. Rincn-Mora

2007-01-01

344

Attenuation of Sinusoidal Perturbations Superimposed on Laminar Flow of a Liquid in a Long Line  

NASA Technical Reports Server (NTRS)

The attenuation constant for sinusoidal pressure and flow perturbations superimposed on the laminar flow of a viscous liquid was measured in a system consisting of a long, straight, cylindrical hydraulic line. The upstream and downstream ends of the line were securely fastened t o the ground. A sinusoidal perturbation was imposed on the mean flow at the upstream end by means of a s m a l l oscillation of a throttle valve abmt a partly open mean position. The downstream end was terminated in a restricting orifice. Pressure perturbations were measured at three locations along the line for frequencies from 15 t o 100 cps. These pressure measurements were reduced by use of a pair of complex damped acoustic one-dimensional wave equations to obtain the attenuation constant along with the phase constant and the dimensionless downstream admittance. For the range of frequencies investigated, the experimental values of the attenuation constant are in good agreement with classical theory.

Holland, Carl M.; Blade, Robert J.; Dorsch, Robert G.

1965-01-01

345

Sinusoidal heating method to noninvasively measure tissue perfusion  

Microsoft Academic Search

Noninvasively measuring the tissue blood perfusion has been an important however difficult problem in the biomedical engineering field. Based on the newly developed phase-shift principle, an improved sinusoidal heating method to estimate the perfusion was proposed in this paper to replace the original heating algorithm. The phase shift between the sinusoidal heat flux and the surface temperature response was both

Jing Liu; Yi-xin Zhou; Zhong-shan Deng

2002-01-01

346

Wind turbines using self-excited three-phase induction generators: an innovative solution for voltage-frequency control  

NASA Astrophysics Data System (ADS)

A considerable number of communities throughout the world, most of them isolated, need hybrid energy solutions either for rural electrification or for the reduction of diesel use. Despite several research projects and demonstrations which have been conducted in recent years, wind-diesel technology remains complex and much too costly. Induction generators are the most robust and common for wind energy systems but this option is a serious challenge for electrical regulation. When a wind turbine is used in an off-grid configuration, either continuously or intermittently, precise and robust regulation is difficult to attain. The voltage parameter regulation option, as was experienced at several remote sites (on islands and in the arctic for example), is a safe, reliable and relatively simple technology, but does not optimize the wave quality and creates instabilities. These difficulties are due to the fact that no theory is available to describe the system, due to the inverse nature of the problem. In order to address and solve the problem of the unstable operation of this wind turbine generator, an innovative approach is described, based on a different induction generator single phase equivalent circuit.

Brudny, J. F.; Pusca, R.; Roisse, H.

2008-08-01

347

LINEAR FIBROBLAST ALIGNMENT ON SINUSOIDAL WAVE MICROPATTERNS  

PubMed Central

Micrometer and nanometer grooved surfaces have been determined to influence cellular orientation, morphology, and migration through contact guidance. Cells typically elongate along the direction of an underlying groove and often migrate with guidance provided by constraints of the pattern. This phenomenon has been studied primarily using linear grooves, post, or well patterns. We investigated the behavior of mouse embryonic fibroblasts on non-linear, sinusoidal wave grooves created via electron beam lithography on a polymethyl methacrylate (PMMA) substrate that was spin-coated onto a positively charged glass surface. Three different wave patterns, with varying wavelengths and amplitudes, and two different line patterns were created. Cell orientation and adhesion was examined after 4, 24, and 48 hours after cell seeding. Attachment strength was studied via subjecting cells on substrates to centrifugal force following a 24-hour incubation period. For all wave patterns studied, it was noted that cells did not reside within the groove, rather they were observed to cross over each groove, residing both inside and outside of each wave pattern, aligning linearly along the long axis of the pattern. For the linear patterns, we observed that cells tended to reside within the grooves, consistent with previous observations. The ability to add texture to a surface to manipulate cell adhesion strength and growth with only localized attachment, maintaining free space in curvilinear microtopography underlying the cell, may be a useful addition for tissue engineering and the fabrication of novel biomedical devices. PMID:23375052

Gamboa, Jessica R.; Mohandes, Samir; Tran, Phat L.; Slepian, Marvin J.; Yoon, Jeong-Yeol

2013-01-01

348

Suppression of axonal conduction by sinusoidal stimulation in rat hippocampus in vitro  

NASA Astrophysics Data System (ADS)

Deep brain stimulation (DBS), also known as high frequency stimulation (HFS), is a well-established therapy for Parkinson's disease and essential tremor, and shows promise for the therapeutic control of epilepsy. However, the direct effect of DBS on neural elements close to the stimulating electrode remains an important unanswered question. Computational studies have suggested that HFS has a dual effect on neural elements inhibiting cell bodies, while exciting axons. Prior experiments have shown that sinusoidal HFS (50 Hz) can suppress synaptic and non-synaptic cellular activity in several in vitro epilepsy models, in all layers of the hippocampus. However, the effects of HFS on axons near the electrode are still unclear. In the present study, we tested the hypothesis that HFS suppresses axonal conduction in vitro. Sinusoidal HFS was applied to the alvear axon field of transverse rat hippocampal slices. The results show that HFS suppresses the alvear compound action potential (CAP) as well as the CA1 antidromic evoked potential (AEP). Complete suppression was observed as a 100% reduction in the amplitude of the evoked field potential for the duration of the stimulus. Evoked potential width and latency were not significantly affected by sinusoidal HFS. Suppression was dependent on HFS amplitude and frequency, but independent of stimulus duration and synaptic transmission. The frequency dependence of sinusoidal HFS is similar to that observed in clinical DBS, with maximal suppression between 50 and 200 Hz. HFS produced not only suppression of axonal conduction but also a correlated rise in extracellular potassium. These data provide new insights into the effects of HFS on neuronal elements, and show that HFS can block axonal activity through non-synaptic mechanisms.

Jensen, A. L.; Durand, D. M.

2007-06-01

349

High frequency, high temperature specific core loss and dynamic B-H hysteresis loop characteristics of soft magnetic alloys  

NASA Technical Reports Server (NTRS)

Limited experimental data exists for the specific core loss and dynamic B-H loops for soft magnetic materials for the combined conditions of high frequency and high temperature. This experimental study investigates the specific core loss and dynamic B-H loop characteristics of Supermalloy and Metglas 2605SC over the frequency range of 1 to 50 kHz and temperature range of 23 to 300 C under sinusoidal voltage excitation. The experimental setup used to conduct the investigation is described. The effects of the maximum magnetic flux density, frequency, and temperature on the specific core loss and on the size and shape of the B-H loops are examined.

Wieserman, W. R.; Schwarze, G. E.; Niedra, J. M.

1990-01-01

350

High frequency, high temperature specific core loss and dynamic B-H hysteresis loop characteristics of soft magnetic alloys  

NASA Technical Reports Server (NTRS)

Limited experimental data exists for the specific core loss and dynamic B-H loop for soft magnetic materials for the combined conditions of high frequency and high temperature. This experimental study investigates the specific core loss and dynamic B-H loop characteristics of Supermalloy and Metglas 2605SC over the frequency range of 1 to 50 kHz and temperature range of 23 to 300 C under sinusoidal voltage excitation. The experimental setup used to conduct the investigation is described. The effects of the maximum magnetic flux density, frequency, and temperature on the specific core loss and on the size and shape of the B-H loops are examined.

Wieserman, W. R.; Schwarze, G. E.; Niedra, J. M.

1990-01-01

351

PHONETIC PERCEPTION OF SINUSOIDAL SIGNALS: EFFECTS OF AMPLITUDE VARIATION* Robert E. Remez,+ Philip E. Rubin, and Thomas D. Carrell++  

E-print Network

of a sine-wave synthesizer. Figure 2 shows the dif-varying sinusoids. These unnatural- sounding signals mimic the pattern of formant center-frequency and amplitude of fluent speech. Talkers make sounds for listeners to hear. This truism has implicitly motivated many

352

Computer Program for Thin Wire Antenna over a Perfectly Conducting Ground Plane. [using Galerkins method and sinusoidal bases  

NASA Technical Reports Server (NTRS)

A computer program is presented for a thin-wire antenna over a perfect ground plane. The analysis is performed in the frequency domain, and the exterior medium is free space. The antenna may have finite conductivity and lumped loads. The output data includes the current distribution, impedance, radiation efficiency, and gain. The program uses sinusoidal bases and Galerkin's method.

Richmond, J. H.

1974-01-01

353

Liver sinusoidal endothelial cells are responsible for nitric oxide modulation of resistance in the hepatic sinusoids.  

PubMed Central

The mechanisms that regulate vascular resistance in the liver are an area of active investigation. Previously, we have shown that nitric oxide (NO) modulates hepatic vascular tone in the normal rat liver. In this study, the production of NO is examined in further detail by isolating sinusoidal endothelial cells (SEC) from the rat liver. Endothelial NO synthase (eNOS) was present in SEC based on Western blotting and confocal immunofluorescence microscopy. Exposure of SEC to flow increased the release of NO. To investigate the relevance of these in vitro findings to the intact liver, we modified an in situ perfusion system to allow for direct measurement of NO release from the hepatic vasculature. NO was released from the hepatic vasculature in a time-dependent manner, and administration of N-monomethyl-L-arginine reduced NO release and increased portal pressure. Immunostaining of intact liver demonstrated eNOS localization to endothelial cells lining the hepatic sinusoids. These findings demonstrate that SEC in vitro and in vivo express eNOS and produce NO basally, and increase their production in response to flow. Additionally, an increase in portal pressure concomitant with the blockade of NO release directly demonstrates that endogenous endothelial-derived NO modulates portal pressure. PMID:9389760

Shah, V; Haddad, F G; Garcia-Cardena, G; Frangos, J A; Mennone, A; Groszmann, R J; Sessa, W C

1997-01-01

354

Magnetostrictive vibrations model of a three-phase transformer core and the contribution of the fifth harmonic in the grid voltage  

NASA Astrophysics Data System (ADS)

The effect of the fifth harmonic in the grid voltage (with fundamental frequency of 50 Hz) on the vibrations of a three-phase transformer core is computed, since such harmonic has the largest contribution in the European grid voltage. The computational method is a two-dimensional (2D) finite element technique. The modal vibrations under various magnetisations (viz with different fifth harmonic components) are compared with those obtained under a purely sinusoidal magnetisation and showed that the variations for the 100 Hz harmonic of the vibrations are small. However, the 200 Hz harmonic showed a significant increase when a fifth harmonic was present on the applied voltage. In fact, the presence of a fundamental component with 50 Hz frequency and a fifth harmonic on the magnetisation signal generates a 200 Hz harmonic on the magnetostriction strains (and the magnetic forces), and thus this harmonic increases significantly.

Gorji Ghalamestani, Setareh; Vandevelde, Lieven; Dirckx, Joris J. J.; Melkebeek, Jan A. A.

2014-05-01

355

Nonequilibrium atmospheric pressure plasma jet using a combination of 50 kHz/2 MHz dual-frequency power sources  

SciTech Connect

An atmospheric pressure plasma jet is generated by dual sinusoidal wave (50 kHz and 2 MHz). The dual-frequency plasma jet exhibits the advantages of both low frequency and radio frequency plasmas, namely, the long plasma plume and the high electron density. The radio frequency ignition voltage can be reduced significantly by using dual-frequency excitation compared to the conventional radio frequency without the aid of the low frequency excitation source. A larger operating range of ? mode discharge can be obtained using dual-frequency excitation which is important to obtain homogeneous and low-temperature plasma. A larger controllable range of the gas temperature of atmospheric pressure plasma could also be obtained using dual-frequency excitation.

Zhou, Yong-Jie; Yuan, Qiang-Hua; Li, Fei; Wang, Xiao-Min; Yin, Gui-Qin; Dong, Chen-Zhong [Key Laboratory of Atomic and Molecular Physics and Functional Materials of Gansu Province, College of Physics and Electronic Engineering, Northwest Normal University, Lanzhou 730070 (China)] [Key Laboratory of Atomic and Molecular Physics and Functional Materials of Gansu Province, College of Physics and Electronic Engineering, Northwest Normal University, Lanzhou 730070 (China)

2013-11-15

356

Suppression techniques of common-mode voltage generated by voltage source PWM inverter  

Microsoft Academic Search

Voltage source PWM inverters generate high frequency common-mode voltage, which induces high shaft voltage, leads to bearing current, and results in premature bearing failure. The generating mechanism of common-mode voltage of voltage source PWM inverters is discussed, which illustrates that common-mode voltage is ladder-type high dv\\/dt and high frequency step voltage, its amplitude varies with the states of switching devices.

Ma Hongfei; Xu Dianguo; Miao Lijie

2004-01-01

357

Comparison of Various Periodograms for Sinusoid  

E-print Network

of Doppler shift in this case is usually required in order to find its position and speed. A recent-known examples include demodulation of frequency-shift keying signals, wind profiling [2], geolocation

So, Hing-Cheung

358

Fluid Modeling of a Nitrogen Atmospheric-Pressure Planar Dielectric Barrier Discharge Driven by a Realistic Distorted Sinusoidal Alternating Current Power Source  

NASA Astrophysics Data System (ADS)

One-dimensional self-consistent simulations of a parallel-plate atmospheric-pressure nitrogen dielectric barrier discharge (DBD) are presented. The DBD was driven by a realistic distorted-sinusoidal voltage power source with a frequency of 60 kHz. The simulated discharge currents are in quantitative agreement with experimental measurements. N4+ ions gain more of the input electric power than electrons, which is unlike most glow discharges. The densities of all charged and neutral species increase exponentially with increasing applied peak voltage in the range of 6.2-8.6 kV. The higher the permittivity of the dielectric material, the larger the discharge current and the longer the period of gas breakdown. In addition, the quantity of accumulated charges at each electrode increases with increasing permittivity of the dielectric material. Finally, the increase in dielectric thickness from 1.0 to 2.0 mm greatly reduces the densities of all species and also the plasma absorbed by the power.

Cheng, Kai-Wen; Hung, Chieh-Tsan; Lin, Kun-Mo; Chiu, Yuan-Ming; Wu, Jong-Shinn; Yu, Jen-Perng

2012-11-01

359

Compressed domain packet loss concealment of sinusoidally coded speech  

Microsoft Academic Search

We consider the problem of packet loss concealment for voice over IP (VoIP). The speech signal is compressed at the transmitter using a sinusoidal coding scheme working at 8 kbit\\/s. At the receiver, packet loss concealment is carried out working directly on the quantized sinusoidal parameters, based on time-scaling of the packets surrounding the missing ones. Subjective listening tests show

C. A. Rodbro; Muds G. Christensen; S. V. Andersen; S. H. Jensen

2003-01-01

360

System and component design and test of a 10 hp, 18,000 rpm AC dynamometer utilizing a high frequency AC voltage link, part 1  

NASA Astrophysics Data System (ADS)

Hard and soft switching test results conducted with one of the samples of first generation MOS-controlled thyristor (MCTs) and similar test results with several different samples of second generation MCT's are reported. A simple chopper circuit is used to investigate the basic switching characteristics of MCT under hard switching and various types of resonant circuits are used to determine soft switching characteristics of MCT under both zero voltage and zero current switching. Next, operation principles of a pulse density modulated converter (PDMC) for three phase (3F) to 3F two-step power conversion via parallel resonant high frequency (HF) AC link are reviewed. The details for the selection of power switches and other power components required for the construction of the power circuit for the second generation 3F to 3F converter system are discussed. The problems encountered in the first generation system are considered. Design and performance of the first generation 3F to 3F power converter system and field oriented induction moter drive based upon a 3 kVA, 20 kHz parallel resonant HF AC link are described. Low harmonic current at the input and output, unity power factor operation of input, and bidirectional flow capability of the system are shown via both computer and experimental results. The work completed on the construction and testing of the second generation converter and field oriented induction motor drive based upon specifications for a 10 hp squirrel cage dynamometer and a 20 kHz parallel resonant HF AC link is discussed. The induction machine is designed to deliver 10 hp or 7.46 kW when operated as an AC-dynamo with power fed back to the source through the converter. Results presented reveal that the proposed power level requires additional energy storage elements to overcome difficulties with a peak link voltage variation problem that limits reaching to the desired power level. The power level test of the second generation converter after the addition of extra energy storage elements to the HF link are described. The importance of the source voltage level to achieve a better current regulation for the source side PDMC is also briefly discussed. The power levels achieved in the motoring mode of operation show that the proposed power levels achieved in the generating mode of operation can also be easily achieved provided that no mechanical speed limitation were present to drive the induction machine at the proposed power level.

Lipo, Thomas A.; Alan, Irfan

1991-06-01

361

Signal Analysis Algorithms for Optimized Fitting of Nonresonant Laser Induced Thermal Acoustics Damped Sinusoids  

NASA Technical Reports Server (NTRS)

This study seeks a numerical algorithm which optimizes frequency precision for the damped sinusoids generated by the nonresonant LITA technique. It compares computed frequencies, frequency errors, and fit errors obtained using five primary signal analysis methods. Using variations on different algorithms within each primary method, results from 73 fits are presented. Best results are obtained using an AutoRegressive method. Compared to previous results using Prony s method, single shot waveform frequencies are reduced approx.0.4% and frequency errors are reduced by a factor of approx.20 at 303K to approx. 0.1%. We explore the advantages of high waveform sample rates and potential for measurements in low density gases.

Balla, R. Jeffrey; Miller, Corey A.

2008-01-01

362

A nonlinear global model of a dual frequency capacitive discharge  

NASA Astrophysics Data System (ADS)

The behavior of dual frequency capacitively coupled plasmas is investigated. Assuming a realistic reactor configuration represented by effective geometry factors and taking into account two separate sinusoidal voltage sources operating at different frequencies, an ordinary differential equation is derived which describes the nonlinear dynamics of such discharges. An exact analytical solution of the equation is presented and employed for a parameter study of the discharge current characteristics. Simulation results for various gas pressures (=various electron-neutral collision rates), various amplitude ratios of the two independent rf sources, and various integer frequency ratios are shown. When the two frequencies are comparable, surprising nonlinear effects are observed. Particular under study is the heating at the plasma series resonance, either by direct excitation or via the nonlinear electron resonance heating mechanism.

Mussenbrock, Thomas; Ziegler, Dennis; Peter Brinkmann, Ralf

2006-08-01

363

Hepatic sinusoidal obstruction after gemtuzumab ozogamicin (Mylotarg) therapy.  

PubMed

Gemtuzumab ozogamicin (Mylotarg) targets leukemia cells expressing the CD33 receptor by means of a monoclonal antibody conjugated to a cytotoxic agent, calicheamicin. Treatment of acute myeloid leukemia (AML) with gemtuzumab ozogamicin may result in liver injury. We reviewed the course of 23 patients who were given gemtuzumab ozogamicin for AML that had relapsed after hematopoietic cell transplantation. Liver toxicity was assessed through physical examination, serum tests, histologic examination, and hepatic venous pressure measurements. Liver injury developed in 11 patients after gemtuzumab ozogamicin administration; it was manifested as weight gain, ascites, and jaundice in 7 patients. Seven patients died with persistent liver dysfunction and either multiorgan failure or sepsis at a median of 40 days after gemtuzumab ozogamicin infusion. Portal pressure measurements were elevated in 2 patients. Results of liver histologic examination in 5 patients showed sinusoidal injury with extensive sinusoidal fibrosis, centrilobular congestion, and hepatocyte necrosis. Six patients experienced AML remission that was sustained for at least 60 days after gemtuzumab ozogamicin infusion. In summary, hepatic sinusoidal liver injury developed after gemtuzumab ozogamicin infusion. Histology showed striking deposition of sinusoidal collagen, suggesting that gemtuzumab ozogamicin targets CD33(+) cells residing in hepatic sinusoids as the mechanism for its hepatic toxicity. PMID:11895761

Rajvanshi, Pankaj; Shulman, Howard M; Sievers, Eric L; McDonald, George B

2002-04-01

364

SLM-based sinusoidal fringe projection under coherent illumination  

NASA Astrophysics Data System (ADS)

The paper is dedicated to SLM implementation of a sinusoidal phase grating for fringe projection profilometry with sinusoidal fringes. A low-contrast sinusoidal phase grating is capable of projecting focused sinusoidal fringes with satisfactory visibility in a large spatial region under coherent divergent illumination. The paper presents analysis of distortions in the projected fringes due to phase quantization when the phase grating is generated by a phase-only 8-bit SLM. We showed by simulation of propagation in the free space that the spread of intensity fluctuations of the projected fringes comprises 4-5 gray levels if an SLM with a 2? phase span is used and is much lower for an SLM with ?/2 phase span. In addition, we proved that distortion due to the phase encoding of the grating complex amplitude can be modeled as gamma distortion with an invariable behavior in time at small values of the modulation parameter and removed by a proper correction of fringes after polyspectral analysis. The experiments we made with an 8-bit SLM of ?/2 phase span confirmed the ability of this optical element to project sinusoidal fringes with a high spectral purity.

Berberova, Natalia; Stoykova, Elena; Kang, Hoonjong; Park, Joo Sup; Ivanov, Branimir

2013-09-01

365

Phase and amplitude retrieval of objects embedded in a sinusoidal background from its diffraction pattern  

SciTech Connect

Efforts of phase and amplitude retrieval from diffraction patterns have almost exclusively been applied for nonperiodic objects. We investigated the quality of retrieval of nonperiodic objects embedded in a sinusoidal background, using the approach of iterative hybrid input-output with oversampling. Two strategies were employed; one by filtering in the frequency domain prior to phase retrieval, and the other by filtering the phase or amplitude image after retrieval. Results obtained indicate better outcomes with the latter approach provided detector noise is not excessive.

Wu, Chu; Ng, Tuck Wah; Neild, Adrian

2010-04-01

366

AC losses in thin coated conductors under non-sinusoidal conditions  

NASA Astrophysics Data System (ADS)

AC losses in superconducting wires and tapes are usually studied for applied sinusoidal currents and/or magnetic fields. However, currents in electric power systems contain a variety of harmonics. We solved analytically and numerically, in the infinitely thin approximation, the transport current and magnetization problems for coated conductors under non-sinusoidal conditions. The analytical expressions for eddy current and hysteresis losses have been obtained in the framework of the critical state model neglecting the response of the normal-metal substrate and stabilization layers. The contribution of higher harmonics to losses per cycle is determined by both their phase shift relative to the main harmonic and their amplitude. It has been shown that the 5% third current harmonic (for the phase shift ?) increases eddy losses in the normal-metal parts by up to 90% at a transport current close to the critical value. Numerically, for the power law current-voltage characteristic of a superconductor, the contribution of higher harmonics to the total losses in a coated conductor was investigated in a wide range of the power index. It has been shown that even at a low power index (n = 4) this contribution can achieve 44% of losses caused by the main harmonic only. For high external magnetic fields an approximate analytical solution has also been derived and compared to the numerical solution.

Spektor, M.; Meerovich, V.; Sokolovsky, V.; Prigozhin, L.

2012-02-01

367

Improvement of a large-amplitude sinusoidal pressure generator for dynamic calibration of pressure transducers  

NASA Technical Reports Server (NTRS)

Results of research on the improvement of a sinusoidal pressure generator are presented. The generator is an inlet-area-modulated, gas-flow-through device (siren type) which was developed to dynamically calibrate pressure transducers and pressure probes. Tests were performed over a frequency range of 100 Hz to 20 kHz at average chamber pressures (bias pressure) between 30 and 50 psia (21 and 35 N/sq cm abs) and between 150 and 300 psia (104 and 207 N/sq cm abs). Significant improvements in oscillation pressure waveform were obtained but with reduction in available generator oscillation pressure amplitude range. Oscillation pressure amplitude, waveform, and waveform spectral content are given as functions of frequency for the two bias pressure conditions. The generator and instrumentation for frequency, amplitude, and spectrum measurements are described.

Robinson, R. E.

1972-01-01

368

Voltage Drop  

NSDL National Science Digital Library

The first site with information on voltage drop is provided by Power and System Innovations on their Frequently Asked Questions: Voltage Drop (1) page. Visitors can read what voltage drop is, what causes it, what happens as a result of it, and what the maximum recommended voltage drop is. The second site, Basics of Electricity (2), is part of General Electric's Lighting for Business Web site. Through descriptions and illustrations, the site explains what voltage drop is and gives examples of how it is calculated using Ohm's law. The next site is a lab worksheet that is part of a class from the Electrical and Computer Engineering Department of Montana State University called Voltage Drop in Cables (3). The objective of the lesson is to determine the internal resistance of an extension cord and choose the proper wire size for a particular application. Students are given an explanation of the procedure and a number of questions to answer related to the exercise. The Oregon Building Congress offers the Lesson Plans (4) Web site and the downloadable Voltage Drop educational activity. The lesson, which is suggested to be contained within a unit on formulas and solving literal equations, explores the concept of voltage drop that is encountered in basic wiring. The fifth site entitled Explanation of Voltage Drop in a Series Circuit (5) is offered by the Horizons Electronic Lesson Plan Resource. The page describes voltage drop as an electronic concept, gives a formula determining voltage drop, provides a schematic that helps illustrate the concept, and offers a quiz and answer sheet. Next, from electrician.com, is the online Voltage Drop Calculator (6). Users input the type and size of wire being used, the voltage and phase, circuit length, and amp load to calculate voltage drop and several other parameters. The seventh site, entitled The Hazards of Voltage Drop (7), is provided within the Electrical Construction Maintenance Web site. The page describes how electrical equipment can overheat or even power down if it operates below its voltage rating. It also provides a thorough explanation of how to determine the load's operating voltage. The last site, maintained by Williamson Labs (8), is a comprehensive learning site called Elementary Electricity. Visitors will find a wealth of information here, including fun descriptions, graphics, and animations on all aspects of electricity including voltage drop.

369

Sinusoidal galvanic vestibular stimulation (sGVS) induces a vasovagal response in the rat  

PubMed Central

Blood pressure (BP) and heart rate (HR) were studied in isoflurane-anesthetized Long-Evans rats during sinusoidal galvanic vestibular stimulation (sGVS) and sinusoidal oscillation in pitch to characterize vestibular influences on autonomic control of BP and HR. sGVS was delivered binaurally via Ag/AgCl needle electrodes inserted over the mastoids at stimulus frequencies 0.0080.4 Hz. Two processes affecting BP and HR were induced by sGVS: 1) a transient drop in BP (?1520 mmHg) and HR (?3 beat*s?1), followed by a slow recovery over 16 min; and 2) inhibitory modulations in BP (?4.5 mmHg/g) and HR (?0.15 beats*s?1/g) twice in each stimulus cycle. The BP and HR modulations were approximately in-phase with each other and were best evoked by low stimulus frequencies. A wavelet analysis indicated significant energies in BP and HR at scales related to twice and four times the stimulus frequency bands. BP and HR were also modulated by oscillation in pitch at frequencies 0.0250.5 Hz. Sensitivities at 0.025 Hz were ?4.5 mmHg/g (BP) and ?0.17 beat*s?1/g (HR) for pitches of 2090. The tilt-induced BP and HR modulations were out-of-phase, but the frequencies at which responses were elicited by tilt and sGVS were the same. The results show that the sGVS-induced responses, which likely originate in the otolith organs, can exert a powerful inhibitory effect on both BP and HR at low frequencies. These responses have a striking resemblance to human vasovagal responses. Thus, sGVS-activated rats can potentially serve as a useful experimental model of the vasovagal response in humans. PMID:21374078

Martinelli, Giorgio P.; Ogorodnikov, Dmitri; Xiang, Yongqing; Raphan, Theodore; Holstein, Gay R.; Yakushin, Sergei B.

2011-01-01

370

A robust sinusoidal signal processing method for interferometers  

NASA Astrophysics Data System (ADS)

Laser interferometers are widely used as a reference for length measurement. Reliable bidirectional optical fringe counting is normally obtained by using two orthogonally sinusoidal signals derived from the two outputs of an interferometer with path difference. These signals are subject to be disturbed by the geometrical errors of the moving target that causes the separation and shift of two interfering light spots on the detector. It results in typical Heydemann errors, including DC drift, amplitude variation and out-of-orthogonality of two sinusoidal signals that will seriously reduce the accuracy of fringe counting. This paper presents a robust sinusoidal signal processing method to correct the distorted waveforms by hardware. A corresponding circuit board has been designed. A linear stage equipped with a laser displacement interferometer and a height gauge equipped with a linear grating interferometer are used as the test beds. Experimental results show that, even with a seriously disturbed input waveform, the output Lissajous circle can always be stabilized after signal correction. This robust method increases the stability and reliability of the sinusoidal signals for data acquisition device to deal with pulse count and phase subdivision.

Wu, Xiang-long; Zhang, Hui; Tseng, Yang-Yu; Fan, Kuang-Chao

2013-10-01

371

The effect of sinusoidal rolling ground motion on lifting biomechanics  

Microsoft Academic Search

The objective of this study was to quantify the effects of ground surface motion on the biomechanical responses of a person performing a lifting task. A boat motion simulator (BMS) was built to provide a sinusoidal ground motion (simultaneous vertical linear translation and a roll angular displacement) that simulates the deck motion on a small fishing boat. Sixteen participants performed

Xiaopeng Ning; Gary A. Mirka

2010-01-01

372

Sinusoidal reaction formulation for radiation and scattering from conducting surfaces  

NASA Technical Reports Server (NTRS)

A piecewise-sinusoidal reaction technique is developed for scattering and radiation from perfectly conducting bodies of arbitrary shape. The theory and numerical results for scattering patterns of rectangular plates and radiation patterns of corner-reflector antennas are presented. Experimental measurements are included for comparison with the calculated data.

Richmond, J. H.; Wang, N.

1974-01-01

373

Using Antenna Arrays to Motivate the Study of Sinusoids  

ERIC Educational Resources Information Center

Educational activities involving antenna arrays to motivate the study of sinusoids are described. Specifically, using fundamental concepts related to phase and simple geometric arguments, students are asked to predict the location of interference nulls in the radiation pattern of two-element phased array antennas. The location of the radiation

Becker, J. P.

2010-01-01

374

Emotions and Voice Quality: Experiments with Sinusoidal Modeling  

Microsoft Academic Search

Voice quality is recognized to play an important role for the rendering of emotions in verbal communication. In this paper we explore the effectiveness of a sinusoidal modeling process- ing framework for voice transformations finalized to the anal- ysis and synthesis of emotive speech. A set of acoustic cues is selected to compare the voice quality characteristics of the speech

Carlo Drioli; Graziano Tisato; Piero Cosi; Fabio Tesser

375

Miniaturized pattern formation in elastic films cast on sinusoidally patterned substrates.  

PubMed

The various morphologies that are formed when van der Waals forces or electric field is induced between film cast on a sinusoidal substrate and in contact proximity with a contactor or electrode are studied. Remarkably smaller length scales are achieved (?c < 2.96h) than those obtained with films cast on flat substrates. With van der Waals interactions, the patterns are uniformly formed throughout the film but are not regularly ordered. When electric field is used at critical voltage, more ordered, localized patterns are formed at the zones of large local interaction strengths. When these patterns are evolved by increasing the applied voltage, coexistence of all three phases-cavities, stripes, and columns-is observed throughout the film. The localized patterns that are initially formed vary with the voltage applied and strongly dictate the phases of evolution. A patterned substrate/patterned contactor assembly can be made to operate like its unpatterned counterpart by making the interaction strength same everywhere and yet yield uniform, regularly ordered, highly miniaturized patterns. Such patterns are very useful in various applications like microfluidics; they are formed with great ease and can be morphologically tuned by tuning the externally applied electric field. PMID:25238212

Annepu, Hemalatha; Sarkar, Jayati

2014-10-21

376

Detection of DNA hybridization and extension reactions by an extended-gate field-effect transistor: characterizations of immobilized DNA-probes and role of applying a superimposed high-frequency voltage onto a reference electrode.  

PubMed

As we have already shown in a previous publication [Kamahori, M., Ihige, Y., Shimoda, M., 2007. Anal. Sci. 23, 75-79], an extended-gate field-effect transistor (FET) sensor with a gold electrode, on which both DNA probes and 6-hydroxyl-1-hexanethiol (6-HHT) molecules are immobilized, can detect DNA hybridization and extension reactions by applying a superimposed high-frequency voltage to a reference electrode. However, kinetic parameters such as the dissociation constant (K(d)(s)) and the apparent DNA-probe concentration (C(probe)(s)) on a surface were not clarified. In addition, the role of applying the superimposed high-frequency voltage was not considered in detail. In this study, the values of K(d)(s) and C(probe)(s) were estimated using a method involving single-base extension reaction combined with bioluminescence detection. The value of K(d)(s) on the surface was 0.38 microM, which was about six times that in a liquid phase. The value of C(probe)(s), which expressed the upper detection limit for the solid phase reaction, was 0.079 microM at a DNA-probe density of 2.6 x 10(12)molecules/cm(2). We found that applying the superimposed high-frequency voltage accelerated the DNA molecules to reach the gold surface. Also, the distance between the DNA-probes immobilized on the gold surface was controlled to be over 6 nm by applying a method of competitive reaction with DNA probes and 6-HHT molecules. This space was sufficient to enable the immobilized DNA-probes to lie down on the 6-HHT monolayer in the space between them. Thus, the FET sensor could detect DNA hybridization and extension reactions by applying a superimposed high-frequency voltage to the DNA-probes density-controlling gold surface. PMID:18054478

Kamahori, Masao; Ishige, Yu; Shimoda, Maki

2008-02-28

377

LM2907LM2917FrequencytoVoltageConverter February 1995  

E-print Network

speed sensing Y Frequency to voltage conversion (tachometer) Y Speedometers Y Breaker point dwell metersTL H 7942 LM2907LM2917FrequencytoVoltageConverter February 1995 LM2907 LM2917 Frequency to Voltage Converter General Description The LM2907 LM2917 series are monolithic frequency to voltage converters

Wedeward, Kevin

378

CompilerDirected Dynamic Voltage Scaling Based on Program Regions  

E-print Network

voltage is selected that operates cor­ rectly under the reduced clock frequency. Our trace­based compiler voltage scaling is a technique that varies the supply voltage and CPU frequency to provide desired by the regulation loop to adjust the CPU clock frequency with the corresponding minimum voltage level

Kremer, Ulrich

379

Using the reference noise algorithm to suppress pseudo-sinusoidal wave-train noises from seismic data  

NASA Astrophysics Data System (ADS)

Seismic reflection data are always contaminated with short- and long-duration environmental and coherent noise. Long-duration coherent noise usually has a pseudo-sinusoidal wave form. Vehicles and power lines are major sources of environmental pseudo-sinusoidal noise. There are several methods for the attenuation of this noise, each with its own advantages and limitations. In this approach, this noise was considered as the reference noise, assuming that the noise is sinusoidal with phase and amplitude varying with time. To obtain the amplitude of the reference noise, an envelope of absolute data is depicted. To calculate its phase, firstly the frequency content of this noise versus time was calculated using a novel timefrequency transform that we named the weighted Fourier transform. Then, by integrating of calculated frequency, the phase was obtained. In the next step, to construct a trace containing noise, a filter was designed and convolved with reference noise. Then by subtraction of the constructed trace containing noise from the input seismic trace, the observed noise was highly attenuated.

Kourki, Meysam; Riahi, Mohammad Ali

2014-08-01

380

Frequency estimation by linear prediction  

Microsoft Academic Search

The application of linear prediction to frequency estimation for sinusoidal signals in noise is investigated. It is shown that improved performance is obtained by processing a complex-valued version of the real-valued input signal, with the corresponsing sampling rate reduced by one-half. The case of a single sinusoid in white noise is studied in detail, including the eigenvalues of the covariance

Leland B. Jackson; Donald W. Tufts; Frank K. Soong; Rahul M. Rao

1978-01-01

381

Frequency analysis of DC tolerant current transformers  

NASA Astrophysics Data System (ADS)

This article deals with wide frequency range behaviour of DC tolerant current transformers that are usually used in modern static energy meters. In this application current transformers must comply with European and International Standards in their accuracy and DC tolerance. Therefore, the linear DC tolerant current transformers and double core current transformers are used in this field. More details about the problems of these particular types of transformers can be found in our previous works. Although these transformers are designed mainly for power distribution network frequency (50/60 Hz), it can be interesting to understand their behaviour in wider frequency range. Based on this knowledge the new generations of energy meters with measuring quality of electric energy will be produced. This solution brings better measurement of consumption of nonlinear loads or measurement of non-sinusoidal voltage and current sources such as solar cells or fuel cells. The determination of actual power consumption in such energy meters is done using particular harmonics component of current and voltage. We measured the phase and ratio errors that are the most important parameters of current transformers, to characterize several samples of current transformers of both types.

Mlejnek, P.; Kaspar, P.

2013-09-01

382

Frequency modulation television analysis: Threshold impulse analysis. [with computer program  

NASA Technical Reports Server (NTRS)

A computer program is developed to calculate the FM threshold impulse rates as a function of the carrier-to-noise ratio for a specified FM system. The system parameters and a vector of 1024 integers, representing the probability density of the modulating voltage, are required as input parameters. The computer program is utilized to calculate threshold impulse rates for twenty-four sets of measured probability data supplied by NASA and for sinusoidal and Gaussian modulating waveforms. As a result of the analysis several conclusions are drawn: (1) The use of preemphasis in an FM television system improves the threshold by reducing the impulse rate. (2) Sinusoidal modulation produces a total impulse rate which is a practical upper bound for the impulse rates of TV signals providing the same peak deviations. (3) As the moment of the FM spectrum about the center frequency of the predetection filter increases, the impulse rate tends to increase. (4) A spectrum having an expected frequency above (below) the center frequency of the predetection filter produces a higher negative (positive) than positive (negative) impulse rate.

Hodge, W. H.

1973-01-01

383

Voltage Controlled Voltage Source (VCVS)  

NSDL National Science Digital Library

Hosted by Clarkson University, this applet demonstrates a circuit that contains a voltage controlled voltage source (VCVS). The gain may be modified using the scroll bar. Even though brief, this resource can be used in a variety of different technical education classrooms.

Dorf, Richard C.; Svoboda, James A.

2008-11-27

384

Low voltage surface transverse wave oscillators for the next generation CMOS technology.  

PubMed

The design and performance of voltage controlled surface transverse wave oscillators (VCSTWO) in the lower gigahertz frequency range, operating on supply and tuning voltages in the 1.2 to 3.3 V range, and suitable for direct interfacing with the next generation CMOS circuits are presented. By applying the "boost" principle, as used in direct current (DC)-DC converters, to the design of the sustaining amplifier, the VCSTWO outputs are switched between 0 V and a positive peak value, exceeding the supply voltage Us, to provide safe CMOS-circuit switching while keeping the radio frequency (RF)/DC efficiency to a maximum for low DC power consumption. The investigated 1.0 and 2.5 GHz VCSTWO are varactor tuned feedback-loop oscillators stabilized with two-port surface transverse wave (STW) resonators. Each VCSTWO has a DC-coupled, high-impedance switched output to drive the CMOS circuit directly, and an additional sinusoidal 50 ohmz high-power reference output available for other low-noise system applications. Phase noise levels in the -103 to -115 dBc/Hz range at 1 kHz carrier offset are achieved with 1.0 GHz VCSTWO at a RF/DC efficiency in the 21 to 29% range. The 2.5 GHz prototypes demonstrate phase noise levels in the -97 to -102 dBc/Hz range at 1 kHz carrier offset, and efficiencies range between 8 and 15%. PMID:16245594

Avramov, Ivan D

2005-08-01

385

Detection of noise-corrupted sinusoidal signals with Josephson junctions  

NASA Astrophysics Data System (ADS)

We investigate the possibility of exploiting the speed and low noise features of Josephson junctions for detecting sinusoidal signals masked by Gaussian noise. We show that the escape time from the static locked state of a Josephson junction is very sensitive to a small periodic signal embedded in the noise, and therefore the analysis of the escape times can be employed to reveal the presence of the sinusoidal component. We propose and characterize two detection strategies: in the first, the initial phase is supposedly unknown (incoherent strategy), while in the second, the signal phase remains unknown but is fixed (coherent strategy). Our proposals are both suboptimal, with the linear filter being the optimal detection strategy, but they present some remarkable features, such as resonant activation, that make detection through Josephson junctions appealing in some special cases.

Filatrella, Giovanni; Pierro, Vincenzo

2010-10-01

386

Investigation of Calibrating Force Transducer Using Sinusoidal Force  

SciTech Connect

Sinusoidal force calibration method was studied several years before at Physikalisch-Technische Bundesanstalt (PTB). A similar dynamic force calibration system is developed at Changcheng Institute of Metrology and Measurement (CIMM). It uses electro-dynamic shakers to generate dynamic force in the range from 1 N to 20 kN, and heterodyne laser interferometers are used for acceleration measurement. The force transducer to be calibrated is mounted on the shaker, and a mass block is screwed on the top of force transducer, the sinusoidal forces realized by accelerated load masses are traceable to acceleration and mass according to the force definition. The methods of determining Spatial-dependent acceleration on mass block and measuring the end mass of force transducer in dynamic force calibration are discussed in this paper.

Zhang Li [School of Instrumentation Science and Opto-electronics Engineering, Beihang University, Beijing (China); Key Laboratory for Metrology, Changcheng Institute of Metrology and Measurement (CIMM), Beijing 100095 (China); Wang Yu; Zhang Lizhe [Key Laboratory for Metrology, Changcheng Institute of Metrology and Measurement (CIMM), Beijing 100095 (China)

2010-05-28

387

Sinusoidal input describing function for hysteresis followed by elementary backlash  

NASA Technical Reports Server (NTRS)

The author proposes a new sinusoidal input describing function which accounts for the serial combination of hysteresis followed by elementary backlash in a single nonlinear element. The output of the hysteresis element drives the elementary backlash element. Various analytical forms of the describing function are given, depending on the a/A ratio, where a is the half width of the hysteresis band or backlash gap, and A is the amplitude of the assumed input sinusoid, and on the value of the parameter representing the fraction of a attributed to the backlash characteristic. The negative inverse describing function is plotted on a gain-phase plot, and it is seen that a relatively small amount of backlash leads to domination of the backlash character in the describing function. The extent of the region of the gain-phase plane covered by the describing function is such as to guarantee some form of limit cycle behavior in most closed-loop systems.

Ringland, R. F.

1976-01-01

388

Interferometric sensors based on sinusoidal optical path length modulation  

NASA Astrophysics Data System (ADS)

Sinusoidal optical path length modulation of the reference or the measurement arm of an interferometer is a technique which is a fast alternative to white light or phase shifting interferometry. In this paper three different sensors using this periodical modulation are presented. In addition, signal processing algorithms based on Discrete Fourier Transform, Hilbert Transform and parameter estimation are analyzed. These algorithms are used to obtain measurement results which demonstrate the capabilities of the presented interferometric sensors.

Knell, Holger; Schake, Markus; Schulz, Markus; Lehmann, Peter

2014-05-01

389

Evolution of statistical properties for a nonlinearly propagating sinusoid.  

PubMed

The nonlinear propagation of a pure sinusoid is considered using time domain statistics. The probability density function, standard deviation, skewness, kurtosis, and crest factor are computed for both the amplitude and amplitude time derivatives as a function of distance. The amplitude statistics vary only in the postshock realm, while the amplitude derivative statistics vary rapidly in the preshock realm. The statistical analysis also suggests that the sawtooth onset distance can be considered to be earlier than previously realized. PMID:21786869

Shepherd, Micah R; Gee, Kent L; Hanford, Amanda D

2011-07-01

390

The sinusoidal probe: a new approach to improve electrode longevity  

PubMed Central

Micromotion between the brain and implanted electrodes is a major contributor to the failure of invasive brainmachine interfaces. Movements of the electrode tip cause recording instabilities while spike amplitudes decline over the weeks/months post-implantation due to glial cell activation caused by sustained mechanical trauma. We have designed a sinusoidal probe in order to reduce movement of the recording tip relative to the surrounding neural tissue. The probe was microfabricated from flexible materials and incorporated a sinusoidal shaft to minimize tethering forces and a 3D spheroid tip to anchor the recording site within the brain. Compared to standard microwire electrodes, the signal-to-noise ratio and local field potential power of sinusoidal probe recordings from rabbits was more stable across recording periods up to 678 days. Histological quantification of microglia and astrocytes showed reduced neuronal tissue damage especially for the tip region between 6 and 24 months post-implantation. We suggest that the micromotion-reducing measures incorporated into our design, at least partially, decreased the magnitude of gliosis, resulting in enhanced longevity of recording. PMID:24808859

Sohal, Harbaljit S.; Jackson, Andrew; Jackson, Richard; Clowry, Gavin J.; Vassilevski, Konstantin; O'Neill, Anthony; Baker, Stuart N.

2014-01-01

391

Sinusoidal phase modulation as a gate for FROG N. K. Fontaine, R. P. Scott, J. P. Heritage, B. H. Kolner, and S. J. B. Yoo  

E-print Network

Sinusoidal phase modulation as a gate for FROG N. K. Fontaine, R. P. Scott, J. P. Heritage, B. H-correlation frequency-resolved optical gating (PM- FROG) is demonstrated. This low-loss, linear gating technique can be used without separate gate characteri- zation via a blind FROG algorithm with a simple intensity

Kolner, Brian H.

392

Low Voltage Operational Amplifier Design for Energy Harvesting Applications  

E-print Network

voltage with respect to frequency. Figure 7. Gain of the circuit with respect to frequency. In Figure 6 two graphs of output voltage with respect to frequency are shown. The solid line corresponds voltage for the second circuit is significantly higher at high frequencies. Translating this result

Collins, Gary S.

393

A practical implementation of multi-frequency widefield frequency-domain FLIM  

PubMed Central

Widefield frequency-domain fluorescence lifetime imaging microscopy (FD-FLIM) is a fast and accurate method to measure the fluorescence lifetime, especially in kinetic studies in biomedical researches. However, the small range of modulation frequencies available in commercial instruments makes this technique limited in its applications. Here we describe a practical implementation of multi-frequency widefield FD-FLIM using a pulsed supercontinuum laser and a direct digital synthesizer. In this instrument we use a pulse to modulate the image intensifier rather than the more conventional sine wave modulation. This allows parallel multi-frequency FLIM measurement using the Fast Fourier Transform and the cross-correlation technique, which permits precise and simultaneous isolation of individual frequencies. In addition, the pulse modulation at the cathode of image intensifier restored the loss of optical resolution caused by the defocusing effect when the voltage at the cathode is sinusoidally modulated. Furthermore, in our implementation of this technique, data can be graphically analyzed by the phasor method while data are acquired, which allows easy fit-free lifetime analysis of FLIM images. Here our measurements of standard fluorescent samples and a Fster resonance energy transfer pair demonstrate that the widefield multi-frequency FLIM system is a valuable and simple tool in fluorescence imaging studies. PMID:23296945

Chen, Hongtao

2013-01-01

394

Voltage-and frequency-dependent block of diltiazem on the slow inward current and generation of tension in frog ventricular muscle  

Microsoft Academic Search

1.The effects of a new Ca2+-antagonist, diltiazem, were studied in frog ventricular myocardium. The single sucrose gap voltage clamp technique was used to control membrane potential and measure membrane current and tension.2.Diltiazem had no effect on the resting potential, but reduced the slow inward current (Isi) and increased the net outward current.3.Membrane conductance measurements suggest that the increase in the

Leslie Tung; Martin Morad

1983-01-01

395

Design of low-power short-distance opto-electronic transceiver front-ends with scalable supply voltages and frequencies  

Microsoft Academic Search

The need for low-power I\\/Os is widely recognized, as I\\/Os take up a significant portion of total chip power. In recent years, researchers have pointed to the potential system-level power savings that can be realized if dynamic voltage scalable I\\/Os are available. However, substantial challenges remain in building such links. This paper presents the design and implementation details of opto-electronic

Xuning Chen; Gu-yeon Wei; Li-shiuan Peh

2008-01-01

396

Zero-voltage-switching multi-resonant technique-a novel approach to improve performance of high frequency quasi-resonant converters  

Microsoft Academic Search

The power transistor in zero-current-switched quasiresonant converters (ZCS-QRCs) suffers from excessive voltage stress, and the converter regulation characteristics and stability are adversely affected by parasitic oscillations caused by the junction capacitance of the rectifying diode. A novel, multiresonant switch concept is proposed to overcome these problems. A unique multiresonant network arrangement results in absorption of all parasitic components, including transistor

W. A. Tabisz; Fred C. LEE

1988-01-01

397

Cell shape-dependent rectification of surface receptor transport in a sinusoidal electric field.  

PubMed Central

In the presence of an extracellular electric field, transport dynamics of cell surface receptors represent a balance between electromigration and mutual diffusion. Because mutual diffusion is highly dependent on surface geometry, certain asymmetrical cell shapes effectively create an anisotropic resistance to receptor electromigration. If the resistance to receptor transport along a single axis is anisotropic, then an applied sinusoidal electric field will drive a net time-average receptor displacement, effectively rectifying receptor transport. To quantify the importance of this effect, a finite difference mathematical model was formulated and used to describe charged receptor transport in the plane of a plasma membrane. Representative values for receptor electromigration mobility and diffusivity were used. Model responses were examined for low frequency (10(-4)-10 Hz) 10-V/cm fields and compared with experimental measurements of receptor back-diffusion in human fibroblasts. It was found that receptor transport rectification behaved as a low-pass filter; at the tapered ends of cells, sinusoidal electric fields in the 10(-3) Hz frequency range caused a time-averaged accumulation of receptors as great as 2.5 times the initial uniform concentration. The extent of effective rectification of receptor transport was dependent on the rate of geometrical taper. Model studies also demonstrated that receptor crowding could alter transmembrane potential by an order of magnitude more than the transmembrane potential directly induced by the field. These studies suggest that cell shape is important in governing interactions between alternating current (ac) electric fields and cell surface receptors. PMID:8381681

Lee, R C; Gowrishankar, T R; Basch, R M; Patel, P K; Golan, D E

1993-01-01

398

Practical VoltageScaling for FixedPriority RTSystems Saowanee Saewong and Ragunathan (Raj) Rajkumar  

E-print Network

of the supply voltage. Hence, any reductions in the operating frequency of the processor and its supply voltage frequency. Since the power has a quadratic dependency on the supply voltage, scaling the voltage down may need to be re­synchronized. Depending upon the implementation, these frequency­ or voltage

Rajkumar, Ragunathan

399

Study of the generator/motor operation of induction machines in a high frequency link space power system  

NASA Technical Reports Server (NTRS)

Static power conversion systems have traditionally utilized dc current or voltage source links for converting power from one ac or dc form to another since it readily achieves the temporary energy storage required to decouple the input from the output. Such links, however, result in bulky dc capacitors and/or inductors and lead to relatively high losses in the converters due to stresses on the semiconductor switches. The feasibility of utilizing a high frequency sinusoidal voltage link to accomplish the energy storage and decoupling function is examined. In particular, a type of resonant six pulse bridge interface converter is proposed which utilizes zero voltage switching principles to minimize switching losses and uses an easy to implement technique for pulse density modulation to control the amplitude, frequency, and the waveshape of the synthesized low frequency voltage or current. Adaptation of the proposed topology for power conversion to single-phase ac and dc voltage or current outputs is shown to be straight forward. The feasibility of the proposed power circuit and control technique for both active and passive loads are verified by means of simulation and experiment.

Lipo, Thomas A.; Sood, Pradeep K.

1987-01-01

400

Liver Sinusoidal Endothelial Cells Link Hyperinsulinemia to Hepatic Insulin Resistance  

PubMed Central

Insulin signaling in vascular endothelial cells (ECs) is critical to maintain endothelial function but also to mediate insulin action on peripheral glucose disposal. However, gene knockout studies have reached disparate conclusions. Thus, insulin receptor inactivation in ECs does not impair insulin action, whereas inactivation of Irs2 does. Previously, we have shown that endothelial ablation of the three Foxo genes protects mice from atherosclerosis. Interestingly, here we show that mice lacking FoxO isoforms in ECs develop hepatic insulin resistance through excessive generation of nitric oxide (NO) that impairs insulin action in hepatocytes via tyrosine nitration of insulin receptors. Coculture experiments demonstrate that NO produced in liver sinusoidal ECs impairs insulins ability to suppress glucose production in hepatocytes. The effects of liver sinusoidal ECs can be mimicked by NO donors and can be reversed by NO inhibitors in vivo and ex vivo. The findings are consistent with a model in which excessive, rather than reduced, insulin signaling in ECs predisposes to systemic insulin resistance, prompting a reevaluation of current approaches to insulin sensitization. PMID:23349480

Tsuchiya, Kyoichiro; Accili, Domenico

2013-01-01

401

Molecular regulation of sinusoidal liver bile acid transporters during cholestasis.  

PubMed Central

Impairment of the hepatic transport of bile acids and other organic anions will result in the clinically important syndrome of cholestasis. Cloning of a number of specific hepatic organic anion transporters has enabled studies of their molecular regulation during cholestasis. The best characterized transport system is a 50-51 kDa sodium-dependent taurocholate cotransporting polypeptide (ntcp), which mediates the sodium-dependent uptake of conjugated bile acids at the sinusoidal plasma membrane of hepatocytes. Under physiologic conditions and after depletion of biliary constituents, ntcp remains constitutively expressed throughout the liver acinus. However, both function and expression of ntcp are rapidly down-regulated in rat liver in various models of experimental cholestasis, such as cholestasis induced by common bile duct ligation, estrogen, endotoxin or cytokine treatment. In addition to ntcp, the sinusoidal organic anion transporting polypeptide oatp-1 is also down-regulated at the protein and steady-state mRNA levels in estrogen-cholestasis, but does not affect sodium-independent uptake of taurocholate. The regulation of a recently cloned member of the organic anion transporter family (oatp-2), which is highly expressed in liver, remains to be studied under cholestatic conditions. PMID:9626756

Gartung, C.; Matern, S.

1997-01-01

402

Design and fabrication of nano-sinusoid LSPR devices.  

PubMed

Applications of LSPR nano-particles in various areas of solar cells, LSPR biosensors, and SERS biosensors, based on interaction of light with noble metal nano-particles is increasing. Therefore, design and nano-fabrication of the LSPR devices is a key step in developing such applications. Design of nano-structures with desirable spectral properties using numerical techniques such as finite difference time domain (FDTD) is the first step in this work. A new structure called nano-sinusoid, satisfying the some desirable LSPR characteristics, is designed and simulated using the FDTD method. In the next stage, analytical method of electro static eigen mode method is used to validate the simulation results. The, nano-fabrications method of electron beam lithography (EBL) is implemented to fabricate the proposed profile with high precision. Finally, atomic force microscopy (AFM) is used to investigate the shape of the fabricated nano-particles, and the dark field microscopy is employed to demonstrate the particular spectral characteristics of the proposed nano-sinusoids. PMID:25320975

Mortazavi, Daryoush; Kouzani, Abbas; Kalani, Mahshid

2014-08-11

403

Vestibular modulation of muscle sympathetic nerve activity by the utricle during sub-perceptual sinusoidal linear acceleration in humans.  

PubMed

We assessed the capacity for the vestibular utricle to modulate muscle sympathetic nerve activity (MSNA) during sinusoidal linear acceleration at amplitudes extending from imperceptible to clearly perceptible. Subjects (n = 16) were seated in a sealed room, eliminating visual cues, mounted on a linear motor that could deliver peak sinusoidal accelerations of 30 mG in the antero-posterior direction. Subjects sat on a padded chair with their neck and head supported vertically, thereby minimizing somatosensory cues, facing the direction of motion in the anterior direction. Each block of sinusoidal motion was applied at a time unknown to subjects and in a random order of amplitudes (1.25, 2.5, 5, 10, 20 and 30 mG), at a constant frequency of 0.2 Hz. MSNA was recorded via tungsten microelectrodes inserted into muscle fascicles of the common peroneal nerve. Subjects used a linear potentiometer aligned to the axis of motion to indicate any perceived movement, which was compared with the accelerometer signal of actual room movement. On average, 67% correct detection of movement did not occur until 6.5 mG, with correct knowledge of the direction of movement at ~10 mG. Cross-correlation analysis revealed potent sinusoidal modulation of MSNA even at accelerations subjects could not perceive (1.25-5 mG). The modulation index showed a positive linear increase with acceleration amplitude, such that the modulation was significantly higher (25.3 3.7%) at 30 mG than at 1.25 mG (15.5 1.2%). We conclude that selective activation of the vestibular utricle causes a pronounced modulation of MSNA, even at levels well below perceptual threshold, and provides further evidence in support of the importance of vestibulosympathetic reflexes in human cardiovascular control. PMID:24504198

Hammam, Elie; Hau, Chui Luen Vera; Wong, Kwok-Shing; Kwok, Kenny; Macefield, Vaughan G

2014-04-01

404

Optical wideband high-voltage measurement system  

Microsoft Academic Search

A wideband fiber-optic system for the measurement of ac high voltages is presented. The system is based on a capacitively coupled Pockels cell which works as a passive voltage sensor. The lower frequency limit is a few Hz and the upper is 150230 MHz depending on the application. Other system characteristics are excellent electrical noise suppression, large voltage range, high

H. M. Hertz; P. Thomsen

1987-01-01

405

Electronic Shore Power Station Based on Matrix-style Frequency Algorithm  

NASA Astrophysics Data System (ADS)

The current port power supply to foreign ships, there are two ways power-type for owned diesel-powered and frequency conversion unit,In this paper,Proposed electronic shore power station, put forward electronic shore power station's concepts, and gives a whole building program of electronic shore power station based on matrix conversion algorithm, It will change 10 kV/50 Hz (35Kv/50 Hz) input voltage into 440 V/60 Hz low-voltage, not only eliminating intermediate links, but also simplify the hardware circuit and reduce the production cost and improve the competitiveness of enterprises. Simulation and experimental results show that this program has a built shore power station of high power factor, sinusoidal effective, low distortion, environmental pollution and the advantages,It will be very definite practical significance.

Jia-sheng, Li; Lian-jun, Jiang; Biao, Qiu; Wu-mei, Yang

406

The Impact of Voltage Generation on Harmonic Spectra of Current and Flux Density in the Welding Transformer for a Middle Frequency Resistance Spot Welding System  

Microsoft Academic Search

This paper deals with a middle frequency direct current (MFDC) resistance spot welding system (RSWS). It consists of a semiconductor input converter, a single-phase welding transformer with one primary coil and two secondary coils, and a full-wave output rectifier connected to the transformer's secondary coils. The unwanted current spikes in the input converter, caused by interaction among the asymmetrical design

G. Stumberger; K. Dezelak; B. Polajzer; D. Dolinar; B. Klopcic

2008-01-01

407

Stream Segregation in the Perception of Sinusoidally Amplitude-Modulated Tones  

PubMed Central

Amplitude modulation can serve as a cue for segregating streams of sounds from different sources. Here we evaluate stream segregation in humans using ABA- sequences of sinusoidally amplitude modulated (SAM) tones. A and B represent SAM tones with the same carrier frequency (1000, 4000 Hz) and modulation depth (30, 100%). The modulation frequency of the A signals (fmodA) was 30, 100 or 300 Hz, respectively. The modulation frequency of the B signals was up to four octaves higher (?fmod). Three different ABA- tone patterns varying in tone duration and stimulus onset asynchrony were presented to evaluate the effect of forward suppression. Subjects indicated their 1- or 2-stream percept on a touch screen at the end of each ABA- sequence (presentation time 5 or 15 s). Tone pattern, fmodA, ?fmod, carrier frequency, modulation depth and presentation time significantly affected the percentage of a 2-stream percept. The human psychophysical results are compared to responses of avian forebrain neurons evoked by different ABA- SAM tone conditions [1] that were broadly overlapping those of the present study. The neurons also showed significant effects of tone pattern and ?fmod that were comparable to effects observed in the present psychophysical study. Depending on the carrier frequency, modulation frequency, modulation depth and the width of the auditory filters, SAM tones may provide mainly temporal cues (sidebands fall within the range of the filter), spectral cues (sidebands fall outside the range of the filter) or possibly both. A computational model based on excitation pattern differences was used to predict the 50% threshold of 2-stream responses. In conditions for which the model predicts a considerably larger 50% threshold of 2-stream responses (i.e., larger ?fmod at threshold) than was observed, it is unlikely that spectral cues can provide an explanation of stream segregation by SAM. PMID:22984436

Dollezal, Lena-Vanessa; Beutelmann, Rainer; Klump, Georg M.

2012-01-01

408

Voltage-dependent capacitance of human embryonic kidney cells.  

PubMed

We determine membrane capacitance, C as a function of dc voltage for the human embryonic kidney (HEK) cell. C was calculated from the admittance, Y, obtained during a voltage ramp when the HEK cell was held in whole-cell patch-clamp configuration. Y was determined at frequencies of 390.625 and from the measured current, i obtained with a dual-sinusoidal stimulus. We find that the fractional increase in the capacitance, C is small ( < 1%) and grows with the square of the voltage, Psi. C can be described by: C=C(0)(1+alpha(Psi+psi(s))2)[where C(0): Capacitance at 0 volts, psi(s): Difference in surface potential between cytoplasmic and extracellular leaflets and alpha: Proportionality constant]. We find that alpha and psi(s) are 0.120 (+/- 0.01) V(-2) and -0.073 (+/-0.017 V in solutions that contain ion channel blockers and 0.108 (+/- 0.29) V(-2) and -0.023 (+/- 0.009) V when 10 mM sodium salicylate was added to the extracellular solution. This suggests that salicylate does not affect the rate at which C grows with Psi, but reduces the charge asymmetry of the membrane. We also observe an additional linear differential capacitance of about (-46 fFV(-1)) in about 60% of the cells, this additional component acts simultaneously with the quadratic component and was not observed when salicylate was added to the solution. We suggest that the voltage dependent capacitance originates from electromechanical coupling either by electrostriction and/or Maxwell stress effects and estimate that a small electromechanical force (approximately equal to 1 pN) acts at physiological potentials. These results are relevant to understand the electromechanical coupling in outer hair cells (OHCs) of the mammalian cochlea, where an asymmetric bell-shaped C versus Psi relationship is observed upon application of a similar field. Prestin, a membrane protein expressed in OHCs is required to observe this function. When we compare the total charge contributions from HEK cell membrane (7 x 10(4) electrons, 10 pF cell) with that determined for prestin transfected cells (up to 5 x 10(6) electrons) we conclude that the charge contributions from the collective motion of membrane proteins and lipids in the field is dwarfed relative to that when prestin is present. We suggest that the capacitance-voltage relationships should be similar to that observed for HEK cells for OHCs that do not express prestin in their membranes. PMID:16711859

Farrell, Brenda; Do Shope, Cythnia; Brownell, William E

2006-04-01

409

Maintenance of hepatic sinusoidal endothelial cell phenotype in vitro using organ-specific extracellular matrix scaffolds.  

PubMed

Sinusoidal endothelial cells (SECs) are notoriously difficult to culture in vitro. SECs represent a highly specialized endothelial cell (EC) population, and traditional methods of SEC isolation from the liver initiate a process of SEC dedifferentiation. Acellular extracellular matrix (ECM) scaffolds were investigated in a physiologically relevant in vitro culture model for their ability to maintain SEC phenotype. The cell culture model used SECs only or a coculture of SECs with hepatocytes on ECM substrates derived from the liver (L-ECM), bladder (UBM-ECM), or small intestine submucosa (SIS-ECM). The effect of the ECM substrate upon SEC dedifferentiation was evaluated using scanning electron microscopy (SEM) and confocal microscopy. When SECs alone were cultured on uncoated glass slides, collagen I, UBM-ECM, or SIS-ECM, SECs showed signs of dedifferentiation after 1 day. In contrast, SECs alone cultured on L-ECM maintained their differentiated phenotype for at least 3 days, indicated by the presence of many fenestrations on SEC surface, expression of anti-rat hepatic sinusoidal endothelial cells mouse IgG MoAb (SE-1), and lack of expression of CD31. When SECs were cocultured with hepatocytes on any of the ECM scaffolds, the SECs maintained a near-normal fenestrated phenotype for at least 1 day. However, SEM revealed that the shape, size, frequency, and organization of the fenestrations varied greatly depending on ECM source. At all time points, SECs cocultured with hepatocytes on L-ECM maintained the greatest degree of differentiation. The present study demonstrated that the acellular ECM scaffold derived from the liver maintained SEC differentiation in culture longer than any of the tested substrate materials. The replacement of complex tissues and 3-dimensional organs may require specialized scaffolds to support multiple, functional cell phenotypes. PMID:17561801

Sellaro, Tiffany L; Ravindra, Anjani K; Stolz, Donna Beer; Badylak, Stephen F

2007-09-01

410

Hepatic sinusoidal vasodilators improve transplanted cell engraftment and ameliorate microcirculatory perturbations in the liver.  

PubMed

After transplantation, hepatocytes entering liver sinusoids are engrafted, whereas cells entrapped in portal spaces are cleared. We studied whether hepatic sinusoidal dilatation will increase the entry of transplanted cells in the liver lobule, improve cell engraftment, and decrease microcirculatory perturbations. F344 rat hepatocytes were transplanted intrasplenically into syngeneic dipeptidyl peptidase IV (DPPIV)-deficient rats. Animals were treated with adrenergic receptor blockers (phentolamine, labetalol), a calcium channel blocker (nifedipine), and splanchnic vasodilators (nitroglycerine, calcitonin gene-related peptide [CGRP], glucagon). Transplanted cells were localized by histochemistry. The hepatic microcirculation was studied with in vivo videomicroscopy. Changes in cell translocations were analyzed by injection of (99m)Tc-labeled hepatocytes. Pretreatment with phentolamine and nitroglycerine increased transplanted cell entry in liver sinusoids, whereas labetalol, nifedipine, CGRP, and glucagon were ineffective. Increased deposition of transplanted cells in sinusoids resulted in greater cell engraftment. In vivo microscopy showed disruption of sinusoidal blood flow immediately after cell transplantation with circulatory restoration requiring more than 12 to 24 hours after cell transplantation. However, in nitroglycerine-treated animals, sinusoidal blood flow was perturbed less. Nitroglycerine did not meaningfully increase intrapulmonary cell translocations. In conclusion, these findings indicate that hepatic sinusoidal capacitance is regulated by alpha-adrenergic- and nitroglycerine-responsive elements. Sinusoidal vasodilatation benefited intrahepatic distribution of transplanted cells and restored hepatic microcirculation after cell transplantation. This shall facilitate optimization of clinical cell transplantation and offers novel ways to investigate vascular mechanisms regulating hepatic sinusoidal reactivity. PMID:12029617

Slehria, Sanjeev; Rajvanshi, Pankaj; Ito, Yoshiya; Sokhi, Rana P; Bhargava, Kuldeep K; Palestro, Christopher J; McCuskey, Robert S; Gupta, Sanjeev

2002-06-01

411

Resonant circuit which provides dual-frequency excitation for rapid cycling of an electromagnet  

DOEpatents

Disclosed is a novel ring-magnet control circuit that permits synchrotron repetition rates much higher than the frequency of the sinusoidal guide field of the ring magnet during particle acceleration. The control circuit generates sinusoidal excitation currents of different frequencies in the half waves. During radio-frequency acceleration of the synchrotron, the control circuit operates with a lower frequency sine wave and, thereafter, the electromagnets are reset with a higher-frequency half sine wave.

Praeg, W.F.

1982-03-09

412

A combined patch-clamp and electrorotation study of the voltage- and frequency-dependent membrane capacitance caused by structurally dissimilar lipophilic anions.  

PubMed

Interactions of structurally dissimilar anionic compounds with the plasma membrane of HEK293 cells were analyzed by patch clamp and electrorotation. The combined approach provides complementary information on the lipophilicity, preferential affinity of the anions to the inner/outer membrane leaflet, adsorption depth and transmembrane mobility. The anionic species studied here included the well-known lipophilic anions dipicrylamine (DPA(-)), tetraphenylborate (TPB(-)) and [W(2)(CO)(10)(S(2)CH)](-), the putative lipophilic anion B(CF(3))(4)(-) and three new heterocyclic W(CO)(5) derivatives. All tested anions partitioned strongly into the cell membrane, as indicated by the capacitance increase in patch-clamped cells. The capacitance increment exhibited a bell-shaped dependence on membrane voltage. The midpoint potentials of the maximum capacitance increment were negative, indicating the exclusion of lipophilic anions from the outer membrane leaflet. The adsorption depth of the large organic anions DPA(-), TPB(-) and B(CF(3))(4)(-) increased and that of W(CO)(5) derivatives decreased with increasing concentration of mobile charges. In agreement with the patch-clamp data, electrorotation of cells treated with DPA(-) and W(CO)(5) derivatives revealed a large dispersion of membrane capacitance in the kilohertz to megahertz range due to the translocation of mobile charges. In contrast, in the presence of TPB(-) and B(CF(3))(4)(-) no mobile charges could be detected by electrorotation, despite their strong membrane adsorption. Our data suggest that the presence of oxygen atoms in the outer molecular shell is an important factor for the fast translocation ability of lipophilic anions. PMID:18197354

Zimmermann, D; Kiesel, M; Terpitz, U; Zhou, A; Reuss, R; Kraus, J; Schenk, W A; Bamberg, E; Sukhorukov, V L

2008-01-01

413

Membrane transport mechanisms probed by capacitance measurements with megahertz voltage clamp.  

PubMed Central

We have used capacitance measurements with a 1-microsecond voltage clamp technique to probe electrogenic ion-transporter interactions in giant excised membrane patches. The hydrophobic ion dipicrylamine was used to test model predictions for a simple charge-moving reaction. The voltage and frequency dependencies of the apparent dipicrylamine-induced capacitance, monitored by 1-mV sinusoidal perturbations, correspond to single charges moving across 76% of the membrane field at a rate of 9500 s-1 at 0 mV. For the cardiac Na,K pump, the combined presence of cytoplasmic ATP and sodium induces an increase of apparent membrane capacitance which requires the presence of extracellular sodium. The dependencies of capacitance changes on frequency, voltage, ATP, and sodium verify that phosphorylation enables a slow, 300- to 900-s-1, pump transition (the E1-E2 conformational change), which in turn enables fast, electrogenic, extracellular sodium binding reactions. For the GAT1 (gamma-aminobutyric acid,Na,Cl) cotransporter, expressed in Xenopus oocyte membrane, we find that chloride binding from the cytoplasmic side, and probably sodium binding from the extracellular side, results in a decrease of membrane capacitance monitored with 1- to 50-kHz perturbation frequencies. Evidently, ion binding by the GAT1 transporter suppresses an intrinsic fast charge movement which may originate from a mobility of charged residues of the transporter binding sites. The results demonstrate that fast capacitance measurements can provide new insight into electrogenic processes closely associated with ion binding by membrane transporters. Images Fig. 2 Fig. 3 Fig. 4 PMID:7479969

Lu, C C; Kabakov, A; Markin, V S; Mager, S; Frazier, G A; Hilgemann, D W

1995-01-01

414

Experimental studies for determining human discomfort response to vertical sinusoidal vibration  

NASA Technical Reports Server (NTRS)

A study was conducted to investigate several problems related to methodology and design of experiments to obtain human comfort response to vertical sinusoidal vibration. Specifically, the studies were directed to the determination of (1) the adequacy of frequency averaging of vibration data to obtain discomfort predictors, (2) the effect of practice on subject ratings, (3) the effect of the demographic factors of age, sex, and weight, and (4) the relative importance of seat and floor vibrations in the determination of measurement and criteria specification location. Results indicate that accurate prediction of discomfort requires knowledge of both the acceleration level and frequency content of the vibration stimuli. More importantly, the prediction of discomfort was shown to be equally good based upon either floor accelerations or seat accelerations. Furthermore, it was demonstrated that the discomfort levels in different seats resulting from similar vibratory imputs were equal. Therefore, it was recommended that criteria specifications and acceleration measurements be made at the floor location. The results also indicated that practice did not systematically influence discomfort responses nor did the demographic factors of age, weight, and sex contribute to the discomfort response variation.

Dempsey, T. K.; Leatherwood, J. D.

1975-01-01

415

Three-dimensional structured illumination microscopy of liver sinusoidal endothelial cell fenestrations  

Microsoft Academic Search

Fenestrations are pores in liver sinusoidal endothelial cells that filter substrates and debris between the blood and hepatocytes. Fenestrations have significant roles in aging and the regulation of lipoproteins. However their small size (<200nm) has prohibited any functional analysis by light microscopy. We employed structured illumination light microscopy to observe fenestrations in isolated rat liver sinusoidal endothelial cells with great

Victoria C. Cogger; Gregory P. McNerney; Tun Nyunt; Laurie D. DeLeve; Peter McCourt; Brd Smedsrd; David G. Le Couteur; Thomas R. Huser

2010-01-01

416

Independent control of reflex and volitional EMG modulation during sinusoidal pursuit tracking in humans  

Microsoft Academic Search

It is well known that during volitional sinusoidal tracking the long-latency reflex modulates in parallel with the volitional EMG activity. In this study, a series of experiments are reported demonstrating several conditions in which an uncoupling of reflex from volitional activity occurs. The paradigm consists of a visually guided task in which the subject tracked a sinusoid with the wrist.

M. T. V. Johnson; A. N. Kipnis; M. C. Lee; T. J. Ebner

1993-01-01

417

A Self-Learning Solution for Torque Ripple Reduction for Non-Sinusoidal Permanent Magnet  

E-print Network

1 A Self-Learning Solution for Torque Ripple Reduction for Non-Sinusoidal Permanent Magnet Motor in a permanent-magnet non-sinusoidal synchronous motor. Solutions for calculating optimal currents are deduced are shown to confirm the validity of the proposed neural approach. Index Terms--Permanent Magnet Synchronous

Paris-Sud XI, Université de

418

A Self-Learning Solution for Torque Ripple Reduction for Non-Sinusoidal Permanent Magnet  

E-print Network

1 A Self-Learning Solution for Torque Ripple Reduction for Non-Sinusoidal Permanent Magnet Motor in a permanent-magnet non-sinusoidal synchronous motor. Solutions for calculating optimal currents are deduced PERMANENT MAGNET SYNCHRONOUS MOTORS (PMSMs) are widely used in many industrial production systems due

419

Optimal pulse-width modulation for sinusoidal fringe generation with projector defocusing: comment.  

PubMed

We comment on a recent Letter [Opt. Lett. 35, 4121 (2010)], in which the authors discuss an optimal pulse-width modulation (OPWM) method for sinusoidal fringe generation. We consider that the comparison of the squared binary method (SBM) and the sinusoidal pulse-width modulation (SPWM) method has considerable deficiencies. PMID:21403690

Ayubi, Gastn A; Ferrari, Jos A

2011-03-15

420

Tomographic Characterization of Aquifer Heterogeneity with a Sinusoidal Signal  

NASA Astrophysics Data System (ADS)

We have been doing experimental field work using oscillatory pressure waves to investigate the hydraulic conductivity distribution between source and receiver wells. The Darcy's Law proportionality constant, hydraulic conductivity, describes the relative ease or rate at which water can move through a permeable medium and its fine-scale heterogeneity determines preferential flow rates and pathways. Traditional aquifer tests, such as slug and pumping tests, predict bulk hydraulic conductivity values without detailed information about aquifer heterogeneity. The multiple source and receiver signals of a hydraulic tomography aquifer test can estimate interwell heterogeneity, but it requires extensive time to collect and then invert large amounts of tomographic data. We have been using an innovative adaptation of a continuous oscillatory pressure signal to reduce the data collection and processing time associated with a tomography test. The amplitude and phase shift of the sinusoidal pressure signal are related to the hydraulic conductivity. Theory for a homogeneous aquifer predicts that the amplitude should decay exponentially with radial distance and the phase shift should increase linearly with radial distance. Both the exponential decay coefficient and the phase shift should vary inversely with the square root of the hydraulic conductivity. Extension of this simple theory to heterogeneous aquifer systems suggests the hydraulic conductivity should be replaced with a spatially averaged value. Multiple offset gathers (MOG) of ray paths were collected between tomographic well pairs for a given source location. Previous work used air pressure to oscillate the water column in the well. The present work introduces a sinusoidally pumped source regulated by a computer interface. Ray paths were modeled with a spatially weighted straight ray approximation method and analyzed with data processing programs that extend the 3D homogenous spherical radial equation to the heterogeneous case. A numerical model was used to check the heterogeneous extension for accuracy. High quality zero-offset profile ray paths (ZOP) were used to determine hydraulic conductivity, K, at a relatively fine scale and interpreted into representative aquifer models between different tomographic well pairs. The aquifer models were used with MOG data to evaluate the anisotropy ratio and lateral heterogeneity of the aquifer. Two different oscillatory periods, 3 and 30-sec, were evaluated and compared to previous work at the site. Analysis indicates that the 3-sec period data were more sensitive to the anisotropy ratio and both periods are capable of resolving K zones of about 3 feet or 1 meter. In summary, the use of oscillatory pressure waves for hydraulic tomographic reconstruction of hydraulic conductivity distributions looks promising. This work was funded in part by the Strategic Environmental Research and Development Program (SERDP) as project ER-1367.

Lyle, S. A.; McElwee, C. D.

2011-12-01

421

Studies of combined effects of sinusoidal whole body vibrations and noise of varying bandwidths and intensities on TTS 2 in men  

Microsoft Academic Search

This study analyses the data from three laboratory experiments concerning the separate and combined effects on temporary threshold shifts in hearing (TTS2) of sinusoidal low-frequency (5 Hz 2.12 m\\/s2 and 10 Hz 2.65 m\\/s2), whole body vibration (along the Z-axis), and continuous (white) noise with eight different bandwidths and intensity levels of 85 dB(A), 90 dB(A) and 98 dB(A).

Olavi Manninen

1983-01-01

422

Predicting lateralization performance at high frequencies from auditory-nerve spike timing  

E-print Network

Psychophysical sensitivity to interaural time differences (ITD) in the envelope of high- frequency sinusoidally amplitude-modulated (SAM) tones is generally poorer than that to low- frequency pure tones (PT). ITD sensitivity ...

Dreyer, Anna Alexandra

2005-01-01

423

User-perceived Latency Driven Voltage Scaling for Interactive Applications  

E-print Network

,3]. It dynamically ad- justs the clock frequency along with the supply voltage of the pro- cessor to reduce powerUser-perceived Latency Driven Voltage Scaling for Interactive Applications Le Yan Dept are interactive. System-level voltage scaling techniques, such as dynamic voltage scaling (DVS) and adaptive body

Zhong, Lin

424

Swept source optical coherence tomography with external clocking using voltage controlled oscillator  

NASA Astrophysics Data System (ADS)

In this study, a beat signal recalibration method was developed for optical coherence tomography (OCT) with a high-speed wavelength-swept source. By adopting a voltage-controlled oscillator (VCO) modulated by a sinusoidal waveform as a trigger for the OCT system, the broadening of the beat frequency due to laser tuning rate variations was recalibrated. For this study, OCT based on a Fourier domain mode-locked (FDML) laser at a sweep rate of 60.9 kHz was demonstrated. OCT images of 1500409 pixels were obtained with the sensitivity of 100 dB. Temporal frequency variations in the FDML laser and OCT images obtained with the proposed technique were also described. When compared to a conventional recalibration method using optical components, swept source optical coherence tomography operated with a VCO clock exhibited superior performance and high stability. From the experimental results, it was demonstrated that the proposed method is sufficient to recalibrate the time-frequency variations in interferometry with a high-speed wavelength-swept source.

Lee, Eung Je; Kim, Yong Pyung

2011-05-01

425

Profile-based Dynamic Voltage Scheduling using Program Checkpoints Ana Azevedo, Ilya Issenin, Radu Cornea  

E-print Network

-time power budget. We experimented with two heuristics for ad- justing the clock frequency and voltage will refer to both terms frequency scaling and voltage scaling interchangeably, meaning that changes to frequency are accompanied by appropriate ad- justments to voltage. Early related work on dynamic voltage

Veidenbaum, Alexander V.

426

The Synergy between Power-aware Memory Systems and Processor Voltage Scaling  

E-print Network

, there is increased interest in scaling the CPU voltage and clock frequency. Dynamic Voltage Scaling (DVS) is the tech, there has been considerable interest in scaling the CPU supply voltage and clock frequency. Thus point can be chosen temporar- ily. The excitement surrounding voltage/frequency scaling is based

Ellis, Carla

427

Bounds on Power Savings Using Runtime Dynamic Voltage Scaling: An Exact Algorithm and a Lineartime  

E-print Network

@princeton.edu ABSTRACT Dynamic voltage/frequency scaling (DVFS) has been shown to be an efficient power/energy reduction voltage/frequency voltage levels and different pro­ gram states. We then show a fast linear time heuristic dissipation varies linearly with frequency and quadratically with supply voltage as given by the equation

Martonosi, Margaret

428

Robust Frequency Estimation Using Elemental Sets  

Microsoft Academic Search

The extraction of sinusoidal signals from time-series data is a classic problem of ongoing interest in the statistics and signal processing literatures. Obtaining least squares estimates is difficult because the sum of squares has local minima O(1\\/n) apart in the frequencies. In practice the frequencies are often estimated using ad hoc and inefficient methods. Problems of data quality have received

Gordon K. Smyth; Douglas M. Hawkins

2000-01-01

429

Control methods for three-phase active power filters under non-ideal mains voltages  

Microsoft Academic Search

In this paper, the control algorithms for a three-phase three-wired shunt active power filter under distorted or unbalanced mains voltages conditions are analysed. According to the compensation objectives, a direct method, based on the power balance concept is used and compared to the standard pq algorithm. It allows to impose systematically sinusoidal mains currents in phase with the balanced symmetrical

M. Machmoum; N. Bruyant

2000-01-01

430

Low-voltage low-power novel CCII topologies and applications  

Microsoft Academic Search

Novel topologies of second generation current conveyors (CCIIs) working at low supply voltage (lower than 1.5 V) with reduced power consumption (in the ?W range) are presented. The proposed CCII has been applied to the design of different functions such as capacitance multiplication, integrated filtering, sinusoidal waveform generation, grounded and floating inductance simulation, etc.. To extend the dynamic range of

Giuseppe Ferri; Nicola Carlo Guerrini

2001-01-01

431

Performance of low frequency magnetic field meters to sinusoidal and beat-phenomenon magnetic fields  

Microsoft Academic Search

This paper presents the first part of a research work dealing with the performance assessment of commercially available magnetometers. The aim of the article is to make a comparative study on the accuracy of several magnetometers used today by agencies and research institutes to measure magnetic fields produced by power systems in public and work environments. There is still a

C. A. Cortes; H. Brggemeyer; R. Dib; E. Mombello; G. Ratt

2006-01-01

432

Multilevel cascade voltage source inverter with separate DC sources  

DOEpatents

A multilevel cascade voltage source inverter having separate DC sources is described herein. This inverter is applicable to high voltage, high power applications such as flexible AC transmission systems (FACTS) including static VAR generation (SVG), power line conditioning, series compensation, phase shifting and voltage balancing and fuel cell and photovoltaic utility interface systems. The M-level inverter consists of at least one phase wherein each phase has a plurality of full bridge inverters equipped with an independent DC source. This inverter develops a near sinusoidal approximation voltage waveform with only one switching per cycle as the number of levels, M, is increased. The inverter may have either single-phase or multi-phase embodiments connected in either wye or delta configurations. 15 figs.

Peng, F.Z.; Lai, J.S.

1997-06-24

433

Lipids promote survival, proliferation, and maintenance of differentiation of rat liver sinusoidal endothelial cells in vitro  

E-print Network

Primary rat liver sinusoidal endothelial cells (LSEC) are difficult to maintain in a differentiated state in culture for scientific studies or technological applications. Relatively little is known about molecular regulatory ...

Hang, Ta-Chun

434

Use of equivalent Hermitian Hamiltonian for PT-symmetric sinusoidal optical lattices  

NASA Astrophysics Data System (ADS)

We show how the beam dynamics of non-Hermitian PT-symmetric sinusoidal optical lattices can be approached from the point of view of the equivalent Hermitian problem, obtained by an analytic continuation in the transverse spatial variable x. In this latter problem the eigenvalue equation reduces to the Mathieu equation, whose eigenfunctions and properties have been well studied. That being the case, the beam propagation, which parallels the time-development of the wave-function in quantum mechanics, can be calculated using the equivalent of the method of stationary states. We also discuss a model potential that interpolates between a sinusoidal and periodic square well potential, showing that some of the striking properties of the sinusoidal potential, in particular birefringence, become much less prominent as one goes away from the sinusoidal case.

Jones, H. F.

2011-08-01

435

The hepatic sinusoid 'classic and contemporary: a report on the 17th international symposium on cells of the hepatic sinusoid (ISCHS)  

PubMed Central

The 17th ISCHS took place in Osaka, Japan, on 23 to 25 September 2013. This symposium focuses on an exchange of views on the structure and function of hepatic sinusoidal cells in addition to their roles in clinical pathophysiology. PMID:24484528

2014-01-01

436

Analytical study on the three-dimensional temperature field of KDP crystal irradiated by sinusoidal modulated laser  

NASA Astrophysics Data System (ADS)

A general analytical transient temperature field expression of KDP crystal irradiated by sinusoidal modulated laser is obtained by the integral transform method, based on the heat conduction equation of the orthotropic material. The influence of radius, power and frequency of the laser on the transient temperature field of KDP crystal is simulated by Matlab. The results show that the temperature of material has stepwise distribution with time, which shows periodical stable distribution after some time, and it increases with the decrease of the laser radius and the increase of the laser power. The above results provide a theoretical basis for the photothermal displacement technology used in the measurement of the opto-thermal parameters of the KDP crystal.

Zhang, Yingcong; Shen, Hua; Zhu, Rihong

2013-06-01

437

BEAM INDUCED RF CAVITY TRANSIENT VOLTAGE  

SciTech Connect

The authors calculate the transient voltage induced in a radio frequency cavity by the injection of a relativistic bunched beam into a circular accelerator. A simplified model of the beam induced voltage, using a single tone current signal, is generated and compared with the voltage induced by a more realistic model of a point-like bunched beam. The high Q limit of the bunched beam model is shown to be related simply to the simplified model. Both models are shown to induce voltages at the resonant frequency w{sub r} of the cavity and at an integer multiple of the bunch revolution frequency (i.e. the accelerating frequency for powered cavity operation) hw{sub o}. The presence of two near-by frequencies in the cavity leads to a modulation of the carrier wave exp(jhw{sub o}t). A special emphasis is placed in this paper on studying the modulation function. These models prove useful for computing the transient voltage induced in superconducting rf cavities, which was the motivation behind this research. The modulation of the transient cavity voltage discussed in this paper is the physical basis of the recently observed and explained new kind of longitudinal rigid dipole mode which differs from the conventional Robinson mode.

KRAMER,S.L.; WANG,J.M.

1998-11-01

438

Beam induced rf cavity transient voltage  

SciTech Connect

The authors calculate the transient voltage induced in a radio frequency cavity by the injection of a relativistic bunched beam into a circular accelerator. A simplified model of the beam induced voltage, using a single tone current signal, is generated and compared with the voltage induced by a more realistic model of a point-like bunched beam. The high Q limit of the bunched beam model is shown to be related simply to the simplified model. Both models are shown to induce voltages at the resonant frequency {omega}{sub r} of the cavity and at an integer multiple of the bunch revolution frequency (i.e. the accelerating frequency for powered cavity operation) h{omega}{sub {omicron}}. The presence of two nearby frequencies in the cavity leads to a modulation of the carrier wave exp(h{omega}{sub {omicron}}t). A special emphasis is placed in this paper on studying the modulation function. These models prove useful for computing the transient voltage induced in superconducting rf cavities, which was the motivation behind this research. The modulation of the transient cavity voltage discussed in this paper is the physical basis of the recently observed and explained new kinds of longitudinal rigid dipole mode which differs from the conventional Robinson mode.

Kramer, S.L.; Wang, J.M. [Brookhaven National Lab., Upton, NY (United States)

1998-10-01

439

Responses of central vestibular neurons to sinusoidal yaw rotation in compensated macaques after unilateral labyrinthectomy  

PubMed Central

After vestibular labyrinth injury, behavioral measures of vestibular function partially recover through the process of vestibular compensation. The present study was performed to improve our understanding of the physiology of macaque vestibular nucleus neurons in the compensated state (>6 wk) after unilateral labyrinthectomy (UL). The responses of neurons to sinusoidal yaw rotation at a series of frequencies (0.12.0 Hz) and peak velocities (7.5210/s) were examined to determine how the behavior of these cells differed from those in animals with intact labyrinths. The sensitivity of neurons responding to ipsilateral rotation (type I) did not differ between the intact and injured sides after UL, although this sensitivity was lower bilaterally after lesion than before lesion. The sensitivity of neurons that increase firing with contralateral rotation (type II) was higher ipsilateral to the UL than before lesion or in the nucleus contralateral to the UL. UL did not increase asymmetry in the responses of individual type I or II neurons to ipsilateral vs. contralateral rotation, nor does it change the power law relationship between neuronal firing and level of stimulation. Increased sensitivities of contralesional type I neurons to the remaining vestibular nerve input and increased efficacy of inhibitory vestibular commissures projecting to the ipsilesional vestibular nucleus appear to be responsible for recovery of dynamic function of central vestibular neurons in compensated animals. The portion of type I neurons on the ipsilesional side is reduced in compensated animals, which likely accounts for the asymmetries in vestibular reflexes and perception that characterize vestibular function after UL. PMID:23864379

Wei, Min

2013-01-01

440

Experimental validation of a high voltage pulse measurement method.  

SciTech Connect

This report describes X-cut lithium niobate's (LiNbO3) utilization for voltage sensing by monitoring the acoustic wave propagation changes through LiNbO3 resulting from applied voltage. Direct current (DC), alternating current (AC) and pulsed voltage signals were applied to the crystal. Voltage induced shift in acoustic wave propagation time scaled quadratically for DC and AC voltages and linearly for pulsed voltages. The measured values ranged from 10 - 273 ps and 189 ps - 2 ns for DC and non-DC voltages, respectively. Data suggests LiNbO3 has a frequency sensitive response to voltage. If voltage source error is eliminated through physical modeling from the uncertainty budget, the sensor's U95 estimated combined uncertainty could decrease to ~0.025% for DC, AC, and pulsed voltage measurements.

Cular, Stefan; Patel, Nishant Bhupendra; Branch, Darren W.

2013-09-01

441

238 IEEE JOURNAL OF SOLID-STATE CIRCUITS, VOL. 41, NO. 1, JANUARY 2006 Ultra-Dynamic Voltage Scaling (UDVS) Using  

E-print Network

the frequency and voltage together to reduce power when lower performance is allowed. Voltage dithering discrete voltage and frequency pairs [1]. The savings are only achiev- able if the voltage and frequency238 IEEE JOURNAL OF SOLID-STATE CIRCUITS, VOL. 41, NO. 1, JANUARY 2006 Ultra-Dynamic Voltage

Calhoun, Benton H.

442

Bounds on Power Savings Using Runtime Dynamic Voltage Scaling: An Exact Algorithm and a Linear-time  

E-print Network

@princeton.edu ABSTRACT Dynamic voltage/frequency scaling (DVFS) has been shown to be an efficient power/energy reduction voltage/frequency voltage levels and different pro- gram states. We then show a fast linear time heuristic dissipation varies linearly with frequency and quadratically with supply voltage as given by the equation

Martonosi, Margaret

443

Transient Voltage Recorder  

NASA Technical Reports Server (NTRS)

A voltage transient recorder can detect lightning induced transient voltages. The recorder detects a lightning induced transient voltage and adjusts input amplifiers to accurately record transient voltage magnitudes. The recorder stores voltage data from numerous monitored channels, or devices. The data is time stamped and can be output in real time, or stored for later retrieval. The transient recorder, in one embodiment, includes an analog-to-digital converter and a voltage threshold detector. When an input voltage exceeds a pre-determined voltage threshold, the recorder stores the incoming voltage magnitude and time of arrival. The recorder also determines if its input amplifier circuits clip the incoming signal or if the incoming signal is too low. If the input data is clipped or too low, the recorder adjusts the gain of the amplifier circuits to accurately acquire subsequent components of the lightning induced transients.

Medelius, Pedro J. (Inventor); Simpson, Howard J. (Inventor)

2002-01-01

444

CMOS Monolithic Voltage Converter ________________________________________________________________ Maxim Integrated Products 1  

E-print Network

or Doubles Input Supply Voltage Selectable Oscillator Frequency: 10kHz/80kHz 88% Typ Conversion Efficiency for both battery-powered and board- level voltage conversion applications. The MAX660 can also doubleMAX660 CMOS Monolithic Voltage Converter

Berns, Hans-Gerd

445

A Digital PFC Controller without Input Voltage Sensing  

E-print Network

is the rectified line voltage, ig is the low-frequency (average) component of the inductor current, and ReA Digital PFC Controller without Input Voltage Sensing Barry Mather, Bhaskar Ramachandran introduces a novel digital PFC (DPFC) control approach that requires no input voltage sensing or current loop

446

Application of the Josephson effect to voltage metrology  

Microsoft Academic Search

The unique ability of a Josephson junction to control the flow of magnetic flux quanta leads to a perfect relationship between frequency and voltage. Over the last 30 years, metrology laboratories have used this effect to greatly improve the accuracy of dc voltage standards. More recent research is focused on combining the ideas of digital signal processing with quantum voltage

SAMUEL P. BENZ; CLARK A. HAMILTON

2004-01-01

447

A High-Efficiency, Auto Mode-Hop, Variable-Voltage, Ripple Control Buck Converter  

E-print Network

conversion is based on applying a voltage pulse (with a specific duty cycle and frequency) to a low pass-power systems that employ the DVFS (dynamic voltage and frequency scaling) technique whereby, depending on the workload of the system, the supply voltage (and correspondingly, the clock frequency) of the system

Pedram, Massoud

448

1.5 GHz single-photon detection at telecommunication wavelengths using sinusoidally gated InGaAs/InP avalanche photodiode.  

PubMed

We report a telecom-band single-photon detector for gigahertz clocked quantum key distribution systems. The single-photon detector is based on a sinusoidally gated InGaAs/InP avalanche photodiode. The gate repetition frequency of the single-photon detector reached 1.5 GHz. A quantum efficiency of 10.8 % at 1550 nm was obtained with a dark count probability per gate of 6.3 x 10(-7) and an afterpulsing probability of 2.8 %. Moreover, the maximum detection rate of the detector is 20 MHz. PMID:19365453

Namekata, Naoto; Adachi, Shunsuke; Inoue, Shuichiro

2009-04-13

449

A projector-camera setup for geometry-invariant frequency demultiplexing  

E-print Network

Consider a projector-camera setup where a sinusoidal pattern is projected onto the scene, and an image of the objects imprinted with the pattern is captured by the camera. In this configuration, the local frequency of the ...

Raskar, Ramesh

450

Rebreathing in the Mapleson A, C and D breathing systems with sinusoidal and exponential flow waveforms.  

PubMed

The degree of rebreathing in Mapleson A, C and D breathing systems for sinusoidal and exponential flow waveforms is analysed mathematically. The effects of altering the I:E ratio and of introducing an expiratory pause are investigated. The results for sinusoidal waveforms closely resemble those for a square wave. Exponential flow waveforms produce results similar to triangular flow waveforms. The Mapleson A system is always the most efficient. The Mapleson C system is efficient when the I:E ratio is 1:1, becoming less efficient with longer expiration and very inefficient with an expiratory pause. The Mapleson D system becomes efficient when the expiratory pause is long. PMID:9485973

Cook, L B

1997-12-01

451

Low distortion automatic phase control circuit. [voltage controlled phase shifter  

NASA Technical Reports Server (NTRS)

A voltage controlled phase shifter is rendered substantially harmonic distortion free over a large dynamic input range by employing two oppositely poled, equally biased varactor diodes as the voltage controlled elements which adjust the phase shift. Control voltages which affect the bias of both diodes equally are used to adjust the phase shift without increasing distortion. A feedback stabilized phase shifter is rendered substantially frequency independent by employing a phase detector to control the phase shift of the voltage controlled phase shifter.

Hauge, G.; Pederson, C. W. (inventors)

1974-01-01

452

Multilevel inverter modulation schemes to eliminate common-mode voltages  

Microsoft Academic Search

It is well known that conventional two-level pulsewidth modulated (PWM) inverters generate high-frequency common-mode voltages with high dv\\/dt. Similarly, commonly used multilevel inverter modulation schemes generate common-mode voltages. Common-mode voltages may cause motor shaft voltages and bearing currents and conducted electromagnetic interference (EMI). Premature motor bearing failures and electronic equipment malfunctions have been reported to be directly related to bearing

Haoran Zhang; Annette von Jouanne; Shaoan Dai; Alan K. Wallace; Fei Wang

2000-01-01

453

Automatic voltage imbalance detector  

DOEpatents

A device for indicating and preventing damage to voltage cells such as galvanic cells and fuel cells connected in series by detecting sequential voltages and comparing these voltages to adjacent voltage cells. The device is implemented by using operational amplifiers and switching circuitry is provided by transistors. The device can be utilized in battery powered electric vehicles to prevent galvanic cell damage and also in series connected fuel cells to prevent fuel cell damage.

Bobbett, Ronald E. (Los Alamos, NM); McCormick, J. Byron (Los Alamos, NM); Kerwin, William J. (Tucson, AZ)

1984-01-01

454

Mixed voltage VLSI design  

NASA Technical Reports Server (NTRS)

A technique for minimizing the power dissipated in a Very Large Scale Integration (VLSI) chip by lowering the operating voltage without any significant penalty in the chip throughput even though low voltage operation results in slower circuits. Since the overall throughput of a VLSI chip depends on the speed of the critical path(s) in the chip, it may be possible to sustain the throughput rates attained at higher voltages by operating the circuits in the critical path(s) with a high voltage while operating the other circuits with a lower voltage to minimize the power dissipation. The interface between the gates which operate at different voltages is crucial for low power dissipation since the interface may possibly have high static current dissipation thus negating the gains of the low voltage operation. The design of a voltage level translator which does the interface between the low voltage and high voltage circuits without any significant static dissipation is presented. Then, the results of the mixed voltage design using a greedy algorithm on three chips for various operating voltages are presented.

Panwar, Ramesh; Rennels, David; Alkalaj, Leon

1993-01-01

455

Model-based adaptive frequency estimator for gear crack fault detection  

Microsoft Academic Search

Detection of gear cracks from vibration data is a difficult task. This paper investigates an alternative to the linear predictor residual fault detection based on the nonlinear adaptive control system concept of frequency esti- mators. The frequency estimator model takes advantage of the sinusoidal nature of vibration and adapts the system model during operation. The low-computational requirements, no-priori knowledge, sinusoidal-based

Geoff McDonald; Qing Zhao

2011-01-01

456

Abstract--The implementation of a low-voltage Zero-Voltage-Switching Quasi-Square-Wave (ZVS-QSW) buck  

E-print Network

is the MOFSET threshold voltage, fMAX is the maximum clock frequency and is the technology dependent velocityAbstract-- The implementation of a low-voltage Zero- Voltage-Switching Quasi-Square-Wave (ZVS-QSW) buck converter capable of meeting the future challenges of low- voltage VRMs is presented

Ng, Wai Tung

457

P2055 Assignment 3 1. One application of an RL circuit is the generation of time-varying high voltage from a low-voltage  

E-print Network

voltage from a low-voltage source, as shown in Fig. 1. (a) What is the current in the circuit a long time the initial voltage across each resistor and across the inductor. (c) How much time elapses before the voltage circuit oscillates at a frequency of 1.00 kHz. Find the values of inductance and capacitance. 4

deYoung, Brad

458

Output voltage regulation in matrix converter fed power electronic transformer for power systems application in electric ship  

Microsoft Academic Search

The system described in this paper uses three matrix converters and a high frequency transformer to achieve isolation and voltage transformation from primary to secondary side. Two matrix converters produce high frequency voltage across a transformer, with open ended primary. A third matrix converter converts the high frequency chopped voltage to line frequency. The non-idealities such as leakage inductance of

Shabari Nath; K. K. Mohapatra; Ned Mohan

2009-01-01

459

Modular voltage source converter  

US Patent & Trademark Office Database

Voltage source converter based on a chain-link cell topology including one or more phases, each of the phases having one or more series-connected chain-link cell modules connected to each other. The output voltage of the voltage source converter is controlled by control signals applied to the series-connected chain-link cell modules. In case of failure of a chain-link cell module, that module is controlled, by the control signals, such that zero output voltage is provided at its output voltage AC terminal.

2013-08-06

460

47 CFR 5.101 - Frequency stability.  

Code of Federal Regulations, 2012 CFR

...Requirements 5.101 Frequency stability. An applicant must propose to use a frequency tolerance that would...granted to use a greater frequency tolerance. Equipment...celsius with an input voltage variation of 85% to...

2012-10-01

461

47 CFR 5.101 - Frequency stability.  

Code of Federal Regulations, 2011 CFR

...Requirements 5.101 Frequency stability. An applicant must propose to use a frequency tolerance that would...granted to use a greater frequency tolerance. Equipment...celsius with an input voltage variation of 85% to...

2011-10-01

462

47 CFR 5.101 - Frequency stability.  

Code of Federal Regulations, 2010 CFR

...Requirements 5.101 Frequency stability. An applicant must propose to use a frequency tolerance that would...granted to use a greater frequency tolerance. Equipment...celsius with an input voltage variation of 85% to...

2010-10-01

463

47 CFR 5.101 - Frequency stability.  

Code of Federal Regulations, 2013 CFR

... 2013-10-01 false Frequency stability. 5.101 Section...Requirements 5.101 Frequency stability. Experimental...remain within the authorized frequency band under normal operating...degrees Celsius with an input voltage variation of 85% to...

2013-10-01

464

Multi-frequency EIT and TAS Hardware Development  

Microsoft Academic Search

We present the development of a multi-frequency EIT (electrical impedance tomography) and TAS (trans- admittance scanner) system. Both systems share a common main platform based on a DSP and wireless serial RF connection to a PC. A digital waveform generator is used in both EIT and TAS producing sinusoidal waveforms with a chosen set of frequencies in the range of

J. K. Seo

465

Dynamic sorption and hygroexpansion of wood wafers exposed to sinusoidally varying humidity  

Microsoft Academic Search

Round wood wafers, 4 mm thick along the grain and 2 cm in cross-sectional diameter, of green basswood (Tilia americana L.), yellow birch (Betula alleghaniensis Britton), and black cherry (Prunus serotina Ehrh.), and initially dried to equilibrium in air of 77% relative humidity and 25C, were exposed to sinusoidally varying relative humidity between 77 and 47% at 25C for many

A. Chomcharn; C. Skaar

1983-01-01

466

Pitch Estimation Based on a Harmonic Sinusoidal Autocorrelation Model and a Time-Domain Matching Scheme  

Microsoft Academic Search

In this paper, a method for the estimation of pitch from noise-corrupted speech observations based on extracting a pitch harmonic and the corresponding harmonic number is pro- posed. Starting from the harmonic representation of clean speech, a simple yet accurate harmonic sinusoidal autocorrelation (HSAC) model is first derived. By employing this HSAC model expressed in terms of the pitch harmonics

Celia Shahnaz; Wei-Ping Zhu; M. Omair Ahmad

2012-01-01

467

Sinusoidal Excitation on the Chua's Circuit Simulation of Limit Cycles and Chaos  

Microsoft Academic Search

Experiments with modelling and simulation of sinusoidal excitation on Chua's circuit are presented. It is demonstrated that the behaviour of the circuit is based on the interaction of two different kinds of energy balance: chaotic behaviour based on a balance between two unstable states of charging, and stable limit cycle behaviour based on the balance between the energy lost in

Erik Lindberg

1994-01-01

468

Sum-of-Sinusoid channel models for wireless ad-hoc networks Supervisor: Dr. Salman Durrani  

E-print Network

1 1. Title: Sum-of-Sinusoid channel models for wireless ad-hoc networks Supervisor: Dr. Salman-to-mobile channels, which are required for design and testing of wireless ad-hoc networks. This project will appeal Mobile Adhoc Networks Supervisor: Dr. Salman Durrani Abstract: Ad hoc networking is currently a very

Durrani, Salman

469

The central role of sinusoidal endothelial cells in hepatic hypoxia-reoxygenation injury in the rat  

Microsoft Academic Search

The role of individual cell types in hepatic hypoxia-reoxygenation (reperfusion) injury has not been completely defined. We therefore examined the effects of hypoxia and hypoxia-reoxygenation on the viability of rat hepatocytes, Kupffer cells, and sinusoidal endothelial cells (SECs) in primary culture and whether direct exposure to hypoxia followed by reoxygenation activated Kupffer cells. Cultures of hepatocytes (purity > 99%), Kupffer

DA Samarasinghe; GC Farrell

1996-01-01

470

[Application of sinusoidal modulated currents and radon therapy in patients with uroliths in upper urinary tracts].  

PubMed

The paper describes the method of elimination of the upper urinary tract uroliths using a combination of the following modalities: sinusoidal modulated currents, drinking of artificial radon water, radon water baths and no-spa medication. Evacuation of the concrements or their fragments from the upper urinary tracts reached 80%. PMID:14650133

Karpukhin, I V; Li, A A; Gusarov, I I; Slepushkina, T G; Dubovsko?, A V; Derevnina, N A

2003-01-01

471

Jeremy McGibbon Page 1 Vertically Vibrated Ball-Chains in a Sinusoidal Potential  

E-print Network

Jeremy McGibbon Page 1 Vertically Vibrated Ball-Chains in a Sinusoidal Potential Jeremy McGibbon Introduction Ordinary ball-chains are seen to exhibit interesting coupled motions when vibrated on a vertically of the chain were taken from directly above by a Nikon D70S camera at 2-3 second intervals. Python code

Morris, Stephen W.

472

Torsion of honeycomb FRP sandwich beams with a sinusoidal core configuration  

Microsoft Academic Search

A combined analytical, numerical and experimental investigation of honeycomb fiber-reinforced polymer (HFRP) sandwich beam samples subjected to torsion loads is conducted. The sandwich panel considered in this study has unique sinusoidal core geometry in the plane extending vertically between face laminates, and it has been used primarily as decking systems in highway bridges. Using a homogenization process and mechanics of

Julio F. Davalos; Pizhong Qiao; Vinod Ramayanam; Luyang Shan; Justin Robinson

2009-01-01

473

Granulocyte colony-stimulating factor increases hepatic sinusoidal perfusion during liver regeneration in mice.  

PubMed

Conditioning with granulocyte colony-stimulating factor (G-CSF) promotes liver regeneration in an experimental small-for-size liver remnant mouse model. The mechanisms involved in this extraordinary G-CSF effect are unknown. The aim of this study was to investigate the influence of G-CSF on the hepatic microvasculature in the regenerating liver. The hepatic sinusoidal microvasculature and microarchitecture of the regenerating liver were evaluated by intravital microscopy in mice. Three experimental groups were compared: (1) unoperated unconditioned animals (control; n = 5), (2) animals conditioned with G-CSF 48 h after 60% partial hepatectomy (G-CSF-PH; n = 6), and (3) animals sham conditioned 48 h after 60% PH (sham-PH; n = 6). PH led to hepatocyte hypertrophy and increased hepatic sinusoidal velocity in the sham-PH and G-CSF-PH groups. Increased sinusoidal diameter and increased hepatic blood flow were observed in the G-CSF-PH group compared to the sham-PH and control groups. Furthermore, there was a strong positive correlation between spleen weight and hepatic sinusoidal diameter in the G-CSF-PH group. The increased hepatic blood flow could explain the observed benefit of G-CSF conditioning during liver regeneration. These results elucidate an unexplored aspect of pharmacological modulation of liver regeneration and motivate further experiments. PMID:18340621

Sidler, Daniel; Studer, Peter; Kpper, Sebastian; Gloor, Beat; Candinas, Daniel; Haier, Jrg; Inderbitzin, Daniel

2008-01-01

474

Ultrafast 2D NMR Spectroscopy Using Sinusoidal Gradients: Principles and Ex Vivo Brain Investigations  

E-print Network

Ultrafast 2D NMR Spectroscopy Using Sinusoidal Gradients: Principles and Ex Vivo Brain ultrafast acquisitions of 2D NMR spectra with suitable spectral widths on a microimaging probe (for both Wiley-Liss, Inc. Key words: ultrafast 2D NMR; magnetic resonance spectros- copy; brain metabolites; 2D

Frydman, Lucio

475

Superimposing noise linearizes the responses of primary muscle spindle afferents to sinusoidal muscle stretch  

Microsoft Academic Search

Experiments were conducted in anaesthetized and spinalized cats to measure the extent to which the non-linear response of Ia afferent fibers to sinusoidal muscle stretch as expressed by the peristimulustime-histograms, PSTHs, can be transformed into a linear one by means of the superposition of random stretch (mechanical noise). The gastrocnemius muscles of one hind leg were stretched and the response

J. Krller; O.-J. Grsser; L.-R. Weiss

1988-01-01

476

Microwave integrated circuit for Josephson voltage standards  

NASA Technical Reports Server (NTRS)

A microwave integrated circuit comprised of one or more Josephson junctions and short sections of microstrip or stripline transmission line is fabricated from thin layers of superconducting metal on a dielectric substrate. The short sections of transmission are combined to form the elements of the circuit and particularly, two microwave resonators. The Josephson junctions are located between the resonators and the impedance of the Josephson junctions forms part of the circuitry that couples the two resonators. The microwave integrated circuit has an application in Josephson voltage standards. In this application, the device is asymmetrically driven at a selected frequency (approximately equal to the resonance frequency of the resonators), and a d.c. bias is applied to the junction. By observing the current voltage characteristic of the junction, a precise voltage, proportional to the frequency of the microwave drive signal, is obtained.

Holdeman, L. B.; Toots, J.; Chang, C. C. (inventors)

1980-01-01

477

CZT-Based High Performance Frequency Estimation  

Microsoft Academic Search

Accurate and high-performance frequency estimation of a noisy sampled sinusoid sequence with short time length and adjacent overlapping has been attracting top focus in the field of signal processing. Based on the CZT of a single-tone sequence, this paper presents a novel improved Rife CZT-interpolated frequency estimator, which develops an improved Rife algorithm on the symmetry of CZT Linear Spectrum

Huang Yuchun; Huang Zailu; Huang Benxiong; Xu Shuhua

2007-01-01

478

Large endolymphatic potentials from low-frequency and infrasonic tones in the guinea pig.  

PubMed

Responses of the ear to low-frequency and infrasonic sounds have not been extensively studied. Understanding how the ear responds to low frequencies is increasingly important as environmental infrasounds are becoming more pervasive from sources such as wind turbines. This study shows endolymphatic potentials in the third cochlear turn from acoustic infrasound (5?Hz) are larger than from tones in the audible range (e.g., 50 and 500?Hz), in some cases with peak-to-peak amplitude greater than 20?mV. These large potentials were suppressed by higher-frequency tones and were rapidly abolished by perilymphatic injection of KCl at the cochlear apex, demonstrating their third-turn origins. Endolymphatic iso-potentials from 5 to 500?Hz were enhanced relative to perilymphatic potentials as frequency was lowered. Probe and infrasonic bias tones were used to study the origin of the enhanced potentials. Potentials were best explained as a saturating response summed with a sinusoidal voltage (Vo), that was phase delayed by an average of 60 relative to the biasing effects of the infrasound. Vo is thought to arise indirectly from hair cell activity, such as from strial potential changes caused by sustained current changes through the hair cells in each half cycle of the infrasound. PMID:23464026

Salt, Alec N; Lichtenhan, Jeffery T; Gill, Ruth M; Hartsock, Jared J

2013-03-01

479

High-Frequency Resonant Transistor DC-DC Converters  

Microsoft Academic Search

Transistor dc-dc converters which employ a resonant circuit are described. A resonant circuit is driven with square waves of current or voltage, and by adjusting the frequency around the resonant point, the voltage on the resonant components can be adjusted to any practical voltage level. By rectifying the voltage across the resonant elements, a dc voltage is obtained which can

Robert L. Steigerwald

1984-01-01

480

Technological Aspects: High Voltage  

E-print Network

This paper covers the theory and technological aspects of high-voltage design for ion sources. Electric field strengths are critical to understanding high-voltage breakdown. The equations governing electric fields and the techniques to solve them are discussed. The fundamental physics of high-voltage breakdown and electrical discharges are outlined. Different types of electrical discharges are catalogued and their behaviour in environments ranging from air to vacuum are detailed. The importance of surfaces is discussed. The principles of designing electrodes and insulators are introduced. The use of high-voltage platforms and their relation to system design are discussed. The use of commercially available high-voltage technology such as connectors, feedthroughs and cables are considered. Different power supply technologies and their procurement are briefly outlined. High-voltage safety, electric shocks and system design rules are covered.

Faircloth, D C

2013-01-01

481

Direct subnanosecond voltage monitors  

SciTech Connect

Advanced system development in the subnanosecond time frame increasingly demands high-resolution voltage measurements for both single-shot and repetitive operation. Voltage monitors having capabilities up to the hundred kilovolt level have been developed for direct measurements in discrete and transmission line geometries. Resolutions of 100 ps at 100 kV to 30 ps at 20 kV have been achieved. Detailed test data is presented and ultimate voltage scaling limits are discussed.

Barth, J.E.; Sajeant, W.J.

1981-01-01

482

Induction motor control system with voltage controlled oscillator circuit  

NASA Technical Reports Server (NTRS)

A voltage controlled oscillator circuit is reported in which there are employed first and second differential amplifiers. The first differential amplifier, being employed as an integrator, develops equal and opposite slopes proportional to an input voltage, and the second differential amplifier functions as a comparator to detect equal amplitude positive and negative selected limits and provides switching signals which gate a transistor switch. The integrating differential amplifier is switched between charging and discharging modes to provide an output of the first differential amplifier which upon the application of wave shaping provides a substantially sinusoidal output signal. A two phased version with a second integrator provides a second 90 deg phase shifted output for induction motor control.

Nola, F. J.; Currie, J. R.; Reid, H., Jr. (inventors)

1973-01-01

483

High voltage RF feedthrough bushing  

DOEpatents

Described is a multi-element, high voltage radio frequency bushing for trmitting RF energy to an antenna located in a vacuum container. The bushing includes a center conductor of complex geometrical shape, an outer coaxial shield conductor, and a thin-walled hollow truncated cone insulator disposed between central and outer conductors. The shape of the center conductor, which includes a reverse curvature portion formed of a radially inwardly directed shoulder and a convex portion, controls the uniformity of the axial surface gradient on the insulator cone. The outer shield has a first substantially cylindrical portion and a second radially inwardly extending truncated cone portion.

Grotz, Glenn F. (Huntington Station, NY)

1984-01-01

484

Defect of Fc receptors and phenotypical changes in sinusoidal endothelial cells in human liver cirrhosis.  

PubMed Central

To analyze the pathological changes occurring in Fc receptors (FcRs) in sinusoidal endothelial cells (SECs) in chronic liver diseases, we first characterized immunohistochemically the SEC FcRs by using monoclonal antibodies (MAbs) to FcRs and then investigated the distribution of the SEC FcRs by using peroxidase-antiperoxidase IgG complexes as a ligand on frozen sections. MAb 2E1 to FcRII reacted with SECs in a similar manner to peroxidase-antiperoxidase IgG and blocked the peroxidase-antiperoxidase IgG binding to SECs, whereas MAbs 3G8 and Leu-11b to FcRIII did not. FcRs in normal liver were found along the sinusoidal walls, except for those in the outer periportal zones, but FcRs in chronic active hepatitis and cirrhosis were intermittently or focally absent. The lengths of the FcR-positive portion of sinusoids in unit areas were respectively about 54% and 76% of the normal values in active and inactive cirrhosis. Where FcRs were absent, the MAbs CD36, CD31, and EN4 revealed the presence of sinusoids and, in active cirrhosis, frequently the thickening of liver cell plates. The FcR-negative SECs in the outer periportal zones of normal livers were different from the SECs of other sites in the presence of PAL-E antigen and a rich amount of EN4 antigen, though these sinusoids possessed Kupffer cells and no perisinusoidal deposition of laminin. The FcR-negative SECs in liver diseases occasionally presented the character of ordinary blood vessels, viz., PAL-E antigen, CD34 antigen, and a deficiency of Kupffer cells, regardless of perisinusoidal laminin deposition. However, they preserved the character of normally FcR-possessing SECs, viz., CD36 antigen, and a small amount of EN4 and CD31 antigens. These findings indicate that the outer-periportal SECs in normal livers are phenotypically different from other SECs and that the SECs in diseased livers frequently undergo phenotypical changes, including loss of FcRs, regardless of perisinusoidal laminin deposition, i.e., capillarization of the sinusoids. These phenotypical changes in SECs may reduce the capacity of FcR-mediated IgG-IC metabolism in diseased livers. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 PMID:7686339

Muro, H.; Shirasawa, H.; Kosugi, I.; Nakamura, S.

1993-01-01

485

Flying-capacitor multilevel converter voltage balance dynamics for pure resistive load  

Microsoft Academic Search

Multilevel converters need voltage balancing to be able to generate an output voltage with high quality. Flying capacitor converter topology has a natural voltage balancing property. Voltage balance dynamics analytical research methods reported to date are essentially based on a frequency domain analysis using double Fourier transform. These complicated methods are not truly analytical, which makes an understanding of parameter

S. Thielemans; A. Ruderman; J. A. Melkebeek

2009-01-01

486

Power-Efficient Pulse Width Modulation DC/DC Converters with Zero Voltage Switching Control  

E-print Network

voltage ripple and the speed of the voltage comparators which has shown to introduce new low-frequency General Terms Design. Keywords DC/DC conversion, zero voltage switching. 1. INTRODUCTION Power consumptionPower-Efficient Pulse Width Modulation DC/DC Converters with Zero Voltage Switching Control Changbo

He, Lei

487

47 CFR 24.135 - Frequency stability.  

Code of Federal Regulations, 2011 CFR

...stability. (a) The frequency stability of the transmitter...ppm) of the center frequency over a temperature variation...Celsius at normal supply voltage, and over a variation...requirement to vary supply voltage. (c) It is acceptable...transmitter to meet this frequency stability...

2011-10-01

488

47 CFR 24.135 - Frequency stability.  

Code of Federal Regulations, 2013 CFR

...stability. (a) The frequency stability of the transmitter...ppm) of the center frequency over a temperature variation...Celsius at normal supply voltage, and over a variation...requirement to vary supply voltage. (c) It is acceptable...transmitter to meet this frequency stability...

2013-10-01

489

47 CFR 24.135 - Frequency stability.  

Code of Federal Regulations, 2010 CFR

...stability. (a) The frequency stability of the transmitter...ppm) of the center frequency over a temperature variation...Celsius at normal supply voltage, and over a variation...requirement to vary supply voltage. (c) It is acceptable...transmitter to meet this frequency stability...

2010-10-01

490

47 CFR 24.135 - Frequency stability.  

Code of Federal Regulations, 2012 CFR

...stability. (a) The frequency stability of the transmitter...ppm) of the center frequency over a temperature variation...Celsius at normal supply voltage, and over a variation...requirement to vary supply voltage. (c) It is acceptable...transmitter to meet this frequency stability...

2012-10-01

491

Adaptive optimization of a lead compensator based upon input command frequency during operations of X-Y positioning table  

E-print Network

based on the specifications from the DSF. As a demonstration, a supervisory controller is developed for an X-Y positioning table which tracks a frequency varying sinusoid. The results show that this control scheme allows costs normally only considered...

Jordan, Eric Alan

2012-06-07

492

ON A CALDERON PROBLEM IN FREQUENCY DIFFERENTIAL ELECTRICAL IMPEDANCE TOMOGRAPHY  

E-print Network

tissue from frequency differential boundary voltages and corresponding currents. Physically one-valued function f H1/2 () and an angular frequency the sinu- soidal voltage f(x) cos(t) is imposed knowledge of +i. At zero frequency only is sought; in such a case the corresponding voltage potential v0

Tamasan, Alexandru C.

493

Semaphorin 3E secreted by damaged hepatocytes regulates the sinusoidal regeneration and liver fibrosis during liver regeneration.  

PubMed

The liver has a remarkable capacity to regenerate after injury. Although the regulatory mechanisms of hepatocytic regeneration have been a subject of intense study, the dynamism of the sinusoids, specialized blood vessels in the liver, remains largely unknown. Transient activation of hepatic stellate cells and hepatic sinusoidal endothelial cells, which constitute the sinusoids, contributes to liver regeneration during acute injury, whereas their sustained activation causes liver fibrosis during chronic injury. We focused on understanding the association between damaged hepatocytes and sinusoidal regeneration or liver fibrogenesis using a carbon tetrachloride-induced liver injury mouse model. Damaged hepatocytes rapidly expressed semaphorin 3E (Sema3e), which induced contraction of sinusoidal endothelial cells and thereby contributed to activating hepatic stellate cells for wound healing. In addition, ectopic and consecutive expression of Sema3e in hepatocytes by the hydrodynamic tail-vein injection method resulted in disorganized regeneration of sinusoids and sustained activation of hepatic stellate cells. In contrast, liver fibrosis ameliorated in Sema3e-knockout mice compared withwild-type mice in a chronic liver injury model. Our results indicate that Sema3e, secreted by damaged hepatocytes, affects sinusoidal regeneration in a paracrine manner during liver regeneration, suggesting that Sema3e is a novel therapeutic target in liver fibrogenesis. PMID:24930441

Yagai, Tomoki; Miyajima, Atsushi; Tanaka, Minoru

2014-08-01

494

Spur-Reduced Digital Sinusoid Generation Using Higher-Order Phase Dithering  

NASA Technical Reports Server (NTRS)

A higher-order phase dithering technique that reduces the complexity of digital sinusoid generation is presented and analyzed. M(sup th) order phase dithering denotes the addition of M independent, uniform variates to the sinusoid phase prior to word-length reduction. Spurious magnitudes due to quantization effects are accelerated from the usual -6 dBc per phase bit to -6(M + 1) dBc per phase bit, while the noise power increases linearly in M. For a given spurious specification, higher-order phase dithering permits the use of fewer phase bits than the non-dithered system, resulting in an exponential reduction in look-up table size, dramatically decreasing system complexity.

Flanagan, M.; Zimmerman, G.

1993-01-01

495

Full-range Fourier domain polarization-sensitive optical coherence tomography using sinusoidal phase modulation  

NASA Astrophysics Data System (ADS)

We present a full-range Fourier domain polarization-sensitive optical coherence tomography technique which is able to obtain images of retardance, fast optical axis and intensity of sample. In this technique, the sinusoidal phase modulation is introduced into the spectral interferograms while the probe beam scans over the sample (B-scan). Then the complex horizontal and vertical signals are reconstructed by demodulation. By the Fourier transformation of the two interferograms, the full range images are obtained. Herein, the typical linear phase modulati