Showing papers on "Sine wave published in 2017"
TL;DR: In this paper, an analytical solution for the one-dimensional acoustic field in a duct with arbitrary mean temperature gradient and mean flow is derived using an adapted WKB approximation, which is a superposition of waves travelling in either direction and thus provides physical insight.
44 citations
TL;DR: The accurate formula of the proposed frequency measurement method is derived by using the maximum sidelobe decay windows and the systematic errors and variances of frequency measurement are analyzed by simulation.
Abstract: This paper proposes a novel three-point interpolation discrete Fourier transform for accurate power system frequency measurement. The accurate formula of the proposed frequency measurement method is derived by using the maximum sidelobe decay windows. Moreover, the influence of white noise on the proposed frequency measurement is analyzed by deducing the expression of frequency measurement variance. The systematic errors and variances of frequency measurement are analyzed by simulation.
37 citations
TL;DR: The ratcheting mechanism is exploited to transport charge-carrying particles, electrons, through an amorphous organic film in which local structural inhomogeneities disrupt the gradients needed for typical electrical conduction to occur efficiently.
Abstract: Ratchets are nonequilibrium devices that produce directional motion of particles from nondirectional forces without using a bias, and are responsible for many types of biological transport, which occur with high yield despite strongly damped and noisy environments. Ratchets operate by breaking time-reversal and spatial symmetries in the direction of transport through application of a time-dependent potential with repeating, asymmetric features. This work demonstrates the ratcheting of electrons within a highly scattering organic bulk-heterojunction layer, and within a device architecture that enables the application of arbitrarily shaped oscillating electric potentials. Light is used to modulate the carrier density, which modifies the current with a nonmonotonic response predicted by theory. This system is driven with a single unbiased sine wave source, enabling the future use of natural oscillation sources such as electromagnetic radiation.
36 citations
TL;DR: The Monash Electrochemistry Simulator (MECSim) software package that allows most aspects of ac voltammetry to be simulated when a single sine wave or a combination of sine waves are superimposed onto a dc ramp is introduced.
36 citations
01 Dec 2017
TL;DR: This paper proposes a simple yet effective exponential decay sine wave like learning rate technique for SGD to improve its convergence speed, accelerating neural network training tremendously.
Abstract: Most state-of-the-art results on image classification tasks were obtained by residual neural networks, which use stochastic gradient descent (SGD) with momentum for training. In most cases, the learning rate drops by a constant factor every pre-defined number of epochs. However, it is difficult and time-consuming to estimate how many epochs to drop the learning rate. To tackle this problem, cyclical learning rate is gaining popularity in gradient-based optimization to improve the convergence speed in accelerated gradient schemes. But cyclical learning rate scheme scans a broad range of learning rate, some of which are not suitable for deep neural network training. In this paper, we propose a simple yet effective exponential decay sine wave like learning rate technique for SGD to improve its convergence speed. In the training process, the learning rate would vary in sine wave way. While the maximum value of sine wave would decay exponentially along with training epochs. An ensemble of wide residual nets with our proposed learning scheme achieves 3.01% and 16.03% errors on CIFAR-10 and CIFAR-100 respectively. Furthermore, our proposed method uses far less number of epochs than most recent learning rate strategies, accelerating neural network training tremendously.
34 citations
TL;DR: In this article, the main methods of small capacitance measurement used in electrical capacitance tomography were presented: the AC method with a sine wave excitation and the charge-discharge method with square-wave excitation.
Abstract: The paper presents the main methods of small capacitance measurement used in electrical capacitance tomography: the AC method with a sine wave excitation and the charge-discharge method with square wave excitation. Construction of synchronous detector for both circuits was discussed. A modified "charge-discharge" method was presented.
31 citations
TL;DR: An improved multipoint interpolated digital Fourier transform (DFT) method for the estimation of sine waves in short records, in the presence of DC components that has better estimations than classic three-point interpolation algorithm and has less computational burden than IEEE-STD-1057.
27 citations
TL;DR: The performances of two state-of-the-art Interpolated Discrete Fourier Transform algorithms are analyzed when sine-wave frequency must be estimated over short observation intervals, allowing the selection of the best frequency estimator for given signal-to-noise-ratio, harmonic content, and number of acquired cycles.
27 citations
TL;DR: In this article, an assorted carrier variable frequency random pulse width modulation (AC-VF-RPWM) method is proposed for a three-phase voltage source inverter-fed induction motor drive.
Abstract: This study presents an assorted carrier-variable frequency random pulse width modulation (AC-VF-RPWM) method in which a new type of mixed carrier wave is proposed for a three-phase voltage source inverter-fed induction motor drive. This study has focused on the reduction of acoustic noise where a deterministic PWM strategy is replaced with a proposed RPWM. Inverted sine carrier, sine carrier and triangle carrier are used to compare with the reference sinusoidal wave to generate the pulse (lead and lag) positions. The two groups (lead and lag) each with three pulse positions are randomly selected and it aims at dispersing the harmonic voltage over a wide band area. The linear feedback shift register-based random bit generation algorithms are used to select the three pulse positions from the lead and lag groups. In addition, a frequency modulator converts the carriers into a randomised frequency, which will give more potency to the randomisation process. The results of co-simulation and experimental evaluation that the proposed method could provide harmonic power spectra of the voltage and current spreading over a much broader band area, as compared with the conventional schemes. In addition, Xilinx XC3S500E FPGA device synthesis results are presented.
24 citations
TL;DR: In this article, two-dimensional numerical models for Wells turbine airfoils, functioning under sinusoidal wave flow conditions, were built, and the running and starting characteristics of the turbine were investigated using a mathematical code.
24 citations
TL;DR: The proposed testing system utilizes an innovative excitation system based on a network of tactile transducers to induce controlled narrow-band frequency stress waves to achieve damage classification with accuracies of 92.5% ± 7.5%.
Abstract: This paper presents a novel non-destructive testing and health monitoring system using a network of tactile transducers and accelerometers for the condition assessment and damage classification of foundation piles and utility poles. While in traditional pile integrity testing an impact hammer with broadband frequency excitation is typically used, the proposed testing system utilizes an innovative excitation system based on a network of tactile transducers to induce controlled narrow-band frequency stress waves. Thereby, the simultaneous excitation of multiple stress wave types and modes is avoided (or at least reduced), and targeted wave forms can be generated. The new testing system enables the testing and monitoring of foundation piles and utility poles where the top is inaccessible, making the new testing system suitable, for example, for the condition assessment of pile structures with obstructed heads and of poles with live wires. For system validation, the new system was experimentally tested on nine timber and concrete poles that were inflicted with several types of damage. The tactile transducers were excited with continuous sine wave signals of 1 kHz frequency. Support vector machines were employed together with advanced signal processing algorithms to distinguish recorded stress wave signals from pole structures with different types of damage. The results show that using fast Fourier transform signals, combined with principal component analysis as the input feature vector for support vector machine (SVM) classifiers with different kernel functions, can achieve damage classification with accuracies of 92.5% ± 7.5%.
TL;DR: In this article, industrial rubber blends (SBR/BR/NR blends) under tension-compression load are used to investigate the influence of a higher frequency (5-Hz) compared to the product relevant frequency (1-Hz).
TL;DR: In this article, a mathematical model for the design of a sinusoidal pressure wave generator is developed to reduce the risks of clogging in a mud pulse generator, and an optimum design method for the generator is provided by combining the developed model and a computational fluid dynamics analysis.
TL;DR: A novel automatic bias control (ABC) method for optical in-phase and quadrature (IQ) modulator is proposed and experimentally demonstrated, and the sensitivity of the proposed ABC method outperforms that of the traditional dither frequency monitoring method.
Abstract: A novel automatic bias control (ABC) method for optical in-phase and quadrature (IQ) modulator is proposed and experimentally demonstrated. In the proposed method, two different low frequency sine wave dither signals are generated and added on to the I/Q bias signal respectively. Instead of power monitoring of the harmonics of the dither signal, dither-correlation detection is proposed and used to adjust the bias voltages of the optical IQ modulator. By this way, not only frequency spectral analysis isn't required but also the directional bias adjustment could be realized, resulting in the decrease of algorithm complexity and the growth of convergence rate of ABC algorithm. The results show that the sensitivity of the proposed ABC method outperforms that of the traditional dither frequency monitoring method. Moreover, the proposed ABC method is proved to be modulation-format-free, and the transmission penalty caused by this method for both 10 Gb/s optical QPSK and 17.9 Gb/s optical 16QAM-OFDM signal transmission are negligible in our experiment.
TL;DR: An automatic interpretation method of structure plane parameters in borehole camera image can perform the automatic interpretation of structure planes and extraction of geometric parameters, and provide an effective and consistent solution for drilling information acquisition and bore hole camera image signal processing.
TL;DR: For the applications with low-varying input signals, such as image sensors and ECG readouts, the difference of two consecutive samples is much smaller than the ADC full-scale range for the majority of the input samples, the power consumption of the capacitive digital-to-analog converter, the comparator and the digital circuits of the proposed ADC is saved due to reducing the ADC activity.
Abstract: A novel signal-specific power-efficient analog-to-digital converter (ADC) is proposed for sensor-interface applications Instead of digitizing each analog sample independently, the proposed ADC determines the digital code corresponding to each new input sample by digitizing the difference of two consecutive samples Therefore, for the applications with low-varying input signals, such as image sensors and ECG readouts, the difference of two consecutive samples is much smaller than the ADC full-scale range for the majority of the input samples, the power consumption of the capacitive digital-to-analog converter, the comparator, and the digital circuits of the proposed ADC is saved due to reducing the ADC activity The prototype was fabricated using a 018- ${\mu }\text{m}$ CMOS technology Measurement results of 1 V, 8 bit, 20 kS/s ADC confirm that for a 10-kHz input sine wave, the effective number of bits is 7 while the power consumption of the entire ADC is 112 $ {\mu }\text{W}$ However, for the same sampling rate, the power consumption is only 106 nW for a low-varying 100-Hz input sine wave
TL;DR: A realization that provides dynamic control over relative amplitudes and phases of four coherently interfering beams in gallium phosphide is proposed and numerically demonstrated its capability.
Abstract: A system comprising: a dielectric configured to: a) create a bi-periodic interference pattern of two standing sinusoidal waves on illumination by two pairs of counter-propagating light beams at different incident angles, wherein the incident angles are selected in accordance with the index of refraction of the dielectric to i) to determine the spatial frequency of each counter-propagating light wave pair, and ii) cause total internal reflection, and b) generate, from the bi-periodic interference pattern, an evanescent bi-periodic standing sinusoidal wave; a light source configured to illuminate the dielectric with the two pairs of counter-propagating sinusoidal light waves at the selected incident angles and thereby illuminate a fluorescing object positioned at the surface of the dielectric with the generated bi-periodic evanescent standing sinusoidal wave; and one or more delay lines configured to independently modify the initial phase of each counter-propagating light wave pair.
TL;DR: The results indicate that rogue wave excitation can exist on a stripe phase background for which there are cosine and sine wave background in the two components respectively, and it is proved that the rogue wave number can be n ( n + 1) / 2 + m ( m + 1 ) / 2 (where m, n are arbitrary non-negative integers), in contrast to n (n + 1%) / 2 for scalar nonlinear Schrodinger equation described systems.
TL;DR: A partial dynamic element matching (DEM) technique tailored for HC-DACs is proposed, which reduces the effect of mismatch, while preserving the power and area efficiency of DHSSs.
Abstract: Digital harmonic-cancelling sine-wave synthesizers (DHSSs) use a 47 year old concept, recently revived as a power and area efficient solution for on-chip sine-wave synthesis The operation of a DHSS involves amplitude scaling and summing a set of square-waves to produce a sampled sine-wave The circuit which performs the scaling and summing operation is referred to as the harmonic-cancelling digital-to-analog converter (HC-DAC) Unlike a regular DAC whose amplitude weights are defined by powers of two, an HC-DAC's amplitude weights are defined by a sine function Thus, HC-DACs present intriguing design problems which cannot be solved using the conventional knowledge gathered from designing regular DACs One such problem is managing the effect of mismatch between unit-elements in HC-DACs This paper proposes a partial dynamic element matching (DEM) technique tailored for HC-DACs, which reduces the effect of mismatch, while preserving the power and area efficiency of DHSSs The effectiveness of the DEM technique is evaluated using a DHSS circuit fabricated in an STMicroelectronics 130 nm CMOS technology Test results show that applying the DEM technique increased the figure-of-merit of the DHSS by 40% at 2 MHz output frequency
TL;DR: In this paper, a new method for scaling mode shapes obtained by means of operational modal analysis is presented, which can be used in the presence of ambient vibration from traffic or wind loads, etc.
01 Oct 2017
TL;DR: In this article, the authors constructed three Class-Φ 2 resonant converters with GaN HEMT power devices, 1 kW output power, and switching frequencies of 10 MHz, 30 MHz, and 54.24 MHz.
Abstract: In this paper, we construct three Class-Φ 2 resonant converters with GaN HEMT power devices, 1 kW output power, and switching frequencies of 10 MHz, 30 MHz, and 54.24 MHz. The GaN HEMTs in these converters exhibit losses, approximated thermally, that are significantly higher (up to an order of magnitude) than those predicted by simulation. To investigate, we use a Sawyer-Tower circuit to evaluate the losses in the output capacitance, C OSS , of GaN devices from each manufacturer with commercially-available power devices with voltage ratings over 600 V DS . Losses are reported from 5–35 MHz for sine, square, and Class-Φ 2 waveshapes. Steinmetz curves accurately fit the measured losses across frequency and voltage. C OSS losses for a sine wave with an amplitude equal to the device voltage rating exceed 1 μJ per cycle for two of the three devices tested here, and average C OSS power dissipation with the high-dv/dt Class-Φ 2 waveshape is tens of watts for the best performing device in our study. Higher losses are measured in the cascode device than in the enhancement-mode devices. These losses are not included in manufacturer-provided simulation models or datasheets, and, to our knowledge, were not previously reported in the literature.
TL;DR: It is shown that the described estimator outperforms the LSE and it also provides an estimate of the probability distribution function of the noise before quantization and it uses the values of the transition levels so that a prior quantizer calibration phase is necessary.
Abstract: The estimation of the parameters of a dynamic signal, such as a sine wave, based on quantized data is customarily performed using the least-square estimator (LSE), such as the sine fit. However, the characteristics of the experiments and the measurement setup hardly satisfy the requirements ensuring the LSE to be optimal in the minimum mean-square-error sense. This occurs if the input signal is characterized by a large signal-to-noise ratio resulting in the deterministic component of the quantization error dominating the random error component and when the ADC transition levels are not uniformly distributed over the quantizer input range. In this paper, it is first shown that the LSE applied to quantized data does not perform as expected when the quantizer is not uniform. Then, an estimator is introduced that overcomes these limitations. It uses the values of the transition levels so that a prior quantizer calibration phase is necessary. The estimator properties are analyzed and both numerical and experimental results are described to illustrate its performance. It is shown that the described estimator outperforms the LSE and it also provides an estimate of the probability distribution function of the noise before quantization.
TL;DR: In this article, an analytical expression for the variance of the Interpolated DTFT (IpDTFT) frequency estimator due to additive wideband noise is derived in the case when the acquired sine-wave samples are weighted by a Maximum Sidelobe Decay (MSD) window.
TL;DR: This work presents for the first time, to the best of its knowledge, an InGaAs/InP SPD with 1.25 GHz sine wave gating (SWG) using a monolithically integrated readout circuit (MIRC), and describes the functionality and reliability of the MIRC.
Abstract: InGaAs/InP single-photon detectors (SPDs) are the key devices for applications requiring near-infrared single-photon detection. Gating mode is an effective approach to synchronous single-photon detection. Increasing gating frequency and reducing module size are important challenges for the design of such detector system. Here we present for the first time an InGaAs/InP SPD with 1.25 GHz sine wave gating using a monolithically integrated readout circuit (MIRC). The MIRC has a size of 15 mm * 15 mm and implements the miniaturization of avalanche extraction for high-frequency sine wave gating. In the MIRC, low-pass filters and a low-noise radio frequency amplifier are integrated based on the technique of low temperature co-fired ceramic, which can effectively reduce the parasitic capacitance and extract weak avalanche signals. We then characterize the InGaAs/InP SPD to verify the functionality and reliability of MIRC, and the SPD exhibits excellent performance with 27.5 % photon detection efficiency, 1.2 kcps dark count rate, and 9.1 % afterpulse probability at 223 K and 100 ns hold-off time. With this MIRC, one can further design miniaturized high-frequency SPD modules that are highly required for practical applications.
01 Jan 2017
TL;DR: In this paper, the surface response to excitation (SuRE) method was developed to detect the defects and loading condition changes on plates without using the impedance analyzer, which can be used effectively for detection of damage and estimation of its severity in pipe like structures.
Abstract: The Surface response to excitation (SuRE) method was developed to detect the defects and loading condition changes on plates without using the impedance analyzer. The SuRE method excites the surface with a piezoelectric exciter. Generally, sweep sine wave is continuously applied and surface waves are monitored with (a) piezoelectric element(s) or noncontact sensor(s). The change of the spectral characteristics is quantified by using the sum of the squares of the differences (SSD) to detect the defects. In this study, the SuRE method was implemented for detection of the defects in pipes. The surface of a pipe was excited with a continuous sweep sine wave and the dynamic response of the pipe on selected points were monitored by using a scanning laser vibrometer. The study shows that the SuRE method can be used effectively for detection of damage and estimation of its severity in pipe like structures.
TL;DR: The thickness of the layer, and the decay of the applied field in the z-direction throughout that thickness, provide a mechanism of symmetry breaking in the system that allows the ratchet to produce directional transport using a temporally unbiased oscillation of the AC driving field, a sine wave.
Abstract: Ratcheting is a mechanism that produces directional transport of particles by rectifying nondirectional energy using local asymmetries rather than a net bias in the direction of transport. In a flashing ratchet, an oscillating force (here, an AC field) is applied perpendicular to the direction of transport. In an effort to explore the properties of current experimentally realizable ratchet systems, and to design new ones, this paper describes classical simulations of a damped flashing ratchet that transports charged nanoparticles within a transport layer of finite, non-zero thickness. The thickness of the layer, and the decay of the applied field in the z-direction throughout that thickness, provide a mechanism of symmetry breaking in the system that allows the ratchet to produce directional transport using a temporally unbiased oscillation of the AC driving field, a sine wave. Sine waves are conveniently produced experimentally or harvested from natural sources but cannot produce transport in a 1D or pse...
TL;DR: In this article, the authors describe the tooth surface temperature and the power transmission efficiency of sine-curve and involute gears in the running condition, and show that the sine curve gears for operating condition had lower tooth surface temperatures and higher power transmission efficiencies than those for no-lubrication conditions, but in the greaselubrication condition the superiority of Sine-Curve gears was not observed.
Abstract: The present paper describes the tooth surface temperature and the power transmission efficiency of plastic sinecurve gears in the running condition. The plastic sine-curve and involute gears were manufactured by injection molding. The running tests for sine-curve and involute gears were performed under no-lubrication and greaselubrication conditions, and the tooth surface temperature and the power transmission efficiency were measured. Test results show that the sine-curve gears for operating condition had lower tooth surface temperatures and higher power transmission efficiencies than involute gears under no-lubrication conditions, but in the greaselubrication condition the superiority of sine-curve gears was not observed.
01 Sep 2017
TL;DR: In this article, the soft switching performance of a 1.2 kV half-bridge SiC MOSFET module, FCA150XB120 from Sanrex, was investigated.
Abstract: This paper investigates the soft switching performance of a 1.2 kV half-bridge SiC MOSFET module, FCA150XB120 from Sanrex. The selected module has both MOSFET and diode integrated on a single chip. A single pulse control circuit is employed in a half-bridge series resonant inverter topology with a split dc-link and an LC load in order to emulate a real inverter operation. This results in a square wave output voltage and a sine wave output current where the switching is performed before the zero crossing of current (an inductive mode). In addition, a calorimetric loss measurement is carried out in a 78 kW full-bridge resonant inverter switching at about 200 kHz yielding an efficiency of 99 %. Moreover, this paper aims to find the highest possible switching frequency achievable with the selected module. Besides, the electrically measured loss is compared with the calorimetrically measured loss and the possible reasons for discrepancies are discussed.
16 May 2017
TL;DR: In this paper, a hybrid sine wave filter consisting of an analog and a digital part was designed to achieve low power loss and high current control bandwidth for variable frequency drives (VFDs).
Abstract: Gallium Nitride (GaN) semiconductor devices are promised to be a good alternative to Silicon (Si) semiconductors in future motor inverters for variable frequency drives (VFDs). They combine low on state resistance and low switching losses with a high blocking voltage capability. Compared to actual inverters based on insulated gate bipolar transistors (IGBTs) the pulse width modulation (PWM) frequency for efficient operation can be increased by a factor of 5 to 10, extending the PWM frequency range up to 500 kHz. This allows the use of motor filters with small component size. As a result, high motor efficiency, low torque ripple, high control bandwidth and nearly ideal sinusoidal output voltages are achieved. Therefore this inverters can be used for high speed spindle motors and dynamic servo drives. This paper focus on the design of a hybrid sine wave filter consisting of an analog and a digital part. The filter is optimized to achieve low power loss and high current control bandwidth. A 3-phase GaN motor inverter operating at 200 kHz PWM frequency at 400 V DC-link voltage verifies the system design.