Showing papers on "Sine wave published in 2012"

An error analysis of the dynamic mode decomposition

Abstract: Dynamic mode decomposition (DMD) is a new diagnostic technique in fluid mechanics which is growing in popularity. A powerful analysis tool, it has great potential for measuring the spatial and temporal dynamics of coherent structures in experimental fluid flows. To aid interpretation of experimental data, error-bars on the measured growth rates are needed. In this article, we undertake a massively parallel error analysis of the DMD algorithm using synthetic waveforms that are shown to be representative of the canonical instabilities observed in shear flows. We show that the waveform of the instability has a marked impact on the error of the measured growth rate. Sawtooth and square waves may have an order of magnitude larger error than sine waves under the same conditions. We also show that the effects of data quantity and quality are of critical importance in determining the error in the growth or decay rate, and that the effect of the key parametric variables are modulated by the growth rate itself. We further demonstrate methods by which ensemble and orthogonal data may be introduced to improve the noise response. With regard for the important variables, precise measurement of the growth rates of instabilities may be supplemented with an accurately estimated uncertainty. This opens many new possibilities for the measurement of coherent structure in shear flows.

Advantages of high frequency PWM in AC motor drive applications

Abstract: There are many advantages of using high frequency PWM (in the range of 50 to 100 kHz) in motor drive applications. High motor efficiency, fast control response, lower motor torque ripple, close to ideal sinusoidal motor current waveform, smaller filter size, lower cost filter, etc. are a few of the advantages. However, higher frequency PWM is also associated with severe voltage reflection and motor insulation breakdown issues at the motor terminals. If standard Si IGBT based inverters are employed, losses in the switches make it difficult to overcome significant drop in efficiency of converting electrical power to mechanical power. Work on SiC and GaN based inverter has progressed and variable frequency drives (VFDs) can now be operated efficiently at carrier frequencies in the 50 to 200 kHz range, using these devices. Using soft magnetic material, the overall efficiency of filtering can be improved. The switching characteristics of SiC and GaN devices are such that even at high switching frequency, the turn on and turn off losses are minimal. Hence, there is not much penalty in increasing the carrier frequency of the VFD. Losses in AC motors due to PWM waveform are significantly reduced. All the above features put together improves system efficiency. This paper presents results obtained on using a 6-in-1 GaN module for VFD application, operating at a carrier frequency of 100 kHz with an output sine wave filter. Experimental results show the improvement in motor efficiency and system efficiency on using a GaN based VFD in comparison to the standard Si IGBT based VFD.

A watt-class 1-THz backward-wave oscillator based on sine waveguide

Abstract: A novel backward wave oscillator was proposed by utilizing a concise sine waveguide slow-wave structure combined with sheet electron beam to operate at terahertz frequency band. First, the design method was described, and the dispersion curve and interaction impedance of the sine waveguide were calculated, then the device oscillation frequency and operating voltage were determined. Next, the circuit transmission losses were learned over the tunable frequency range. Finally, the particle-in-cell simulation method was applied to predict its signal generation performance. The investigation results show that, the backward wave oscillator can produce over 1.9 -W peak power output at the central operating frequency of 1-THz under 27-kV operating voltage and 5-mA beam current. And the interaction efficiency at 1-THz is more than 1.4% with a circuit length of 7.2-mm. It, therefore, will be considered as a promising watt-class terahertz radiation source.

Analytical formula for three points sinusoidal signals amplitude estimation errors

Abstract: In this note, we show that the amplitude estimation of sinusoidal signals proposed in Wu and Hong [Wu, S.T., and Hong, J.L. (2010), ‘Five-point Amplitude Estimation of Sinusoidal Signals: With Application to LVDT Signal Conditioning’, IEEE Transactions on Instrumentation and Measurement, 59, 623–630] is a particular case of Vizireanu and Halunga [Vizireanu, D.N, and Halunga, S.V. (2011), ‘Single Sine Wave Parameters Estimation Method Based on Four Equally Spaced Samples’, International Journal of Electronics, 98(7), pp. 941–948]. An analytical formula for amplitude estimation errors as effects of sampling period deviation is obtained.

A Differential Digitally Controlled Crystal Oscillator With a 14-Bit Tuning Resolution and Sine Wave Outputs for Cellular Applications

Abstract: This paper describes the design topologies and considerations of a differential sinusoidal-output digitally controlled crystal oscillator (DCXO) intended for use in cellular applications. The oscillator has a fine-tuning range of ±44 ppm, approximately 14 bits of resolution, and an average step size of 0.005 ppm. All signals connecting externally to I/O pins are sine waves for reducing noise, interference, and spurs couplings. The 26 MHz DCXO fabricated in 65 nm CMOS achieves a phase noise of -149.1 dBc/Hz at 10 kHz offset measured at the sine wave buffer output. The DCXO is capable of meeting the stringent phase noise requirements for IEEE 802.11n 5 GHz WLAN devices. A typical frequency pulling of 0.01 ppm due to turning on/off the sine wave buffer is measured. The DCXO dissipates 1.2 mA of current, whereas each sine wave output buffer draws 1.4 mA. The DXCO occupies a total silicon area of 0.15 mm2 .

Consistency between Fourier transform and small-volume few-wave decomposition for spectral and spatial variability of gravity waves above a typhoon

Abstract: . Convective gravity wave (GW) sources are spatially localized and emit at the same time waves with a wide spectrum of phase speeds. Any wave analysis therefore compromises between spectral and spatial resolution. Future satellite borne limb imagers will for a first time provide real 3-D volumes of observations. These volumes will be however limited which will impose further constraints on the analysis technique. In this study a three dimensional few-wave approach fitting sinusoidal waves to limited 3-D volumes is introduced. The method is applied to simulated GWs above typhoon Ewiniar and GW momentum flux is estimated from temperature fluctuations. Phase speed spectra as well as average profiles of positive, negative and net momentum fluxes are compared to momentum flux estimated by Fourier transform as well as spatial averaging of wind fluctuations. The results agree within 10–20%. The few-wave method can also reveal the spatial orientation of the GWs with respect to the source. The relevance of the results for different types of measurements as well as its applicability to model data is discussed.

A Comparative Analysis of Multi Carrier SPWM Control Strategies using Fifteen Level Cascaded H – bridge Multilevel Inverter

Abstract: In this paper proposes a SPWM control strategy fifteen level cascaded Hbridge multi level inverter. This method introduce sine wave is compared with the triangular carrier wave with different phase relationship. The carrier based Phase disposition PDPWM, PODPWM, APODPWM have been analyzed in this paper. The PWM control strategy method for multi level inverter to reduce the total harmonics distortion in the output waveform. The simulation is done by matlab / simulink environment.

Design and construction of single phase pure sine wave inverter for photovoltaic application

Abstract: This paper discusses the design and construction scheme of an inverter system which converts the DC voltage collected from a photovoltaic (PV) array into AC voltage. The output is a pure sine wave, with the voltage and frequency of the standard grid output. The system consists of a Switch Mode Power Supply (SMPS) and full bridge inverter circuit with a passive filter. The power supply supplies the DC voltage needed to activate the optocouplers, which are connected to the switches of the full bridge circuitry. The optocouplers work as an isolation for the full bridge circuit. High frequency Pulse Width Modulated (PWM) pulses are generated by a microcontroller (PIC18F4431) and provided to the switches of full bridge connection. The full bridge inverter outputs a PWM sine which is later conditioned to pure sine by an L-C filter. Finally, the output voltage and current is measured and displayed on an LCD (Liquid Crystal Diode) display.

Piezoelectric resonator light-emitting-diode (LED) driving circuit

Abstract: A piezoelectric resonant LED driving circuit, wherein a rectifier is used to rectify an AC voltage provided by the supply main into a DC voltage. Then, a quasi-resonant switching module performs resonance by means of the DC voltage to produce an induced current, to raise resonance frequency to operation frequency of a piezoelectric oscillator. Finally, the piezoelectric oscillator performs resonance and filtering using the induced current, to generate a sine wave current. Then, the sine wave current is rectified to output a DC current to drive an LED module.

Development of a grating based multi-degree-of-freedom laser linear encoder using diffracted light

Abstract: A multi-degree-of-freedom laser linear encoder that can simultaneously measure the position, straightness, pitch, roll, and yaw errors of a linear stage is developed The proposed laser encoder uses the phase and spatial information of diffracted light When the light is reflected from a grating and diffracts, the relative movement makes the orders of diffracted light have both phase and spatial geometric variations The proposed encoder design makes the ±1 order diffracted light interfere and outputs pure sine and cosine wave signals for linear displacement The ±2 order diffracted light spots are received by two quadrant photodiode detectors and analyzed to inversely calculate the other motion errors The experimental results show that the measurement error is ±06 μm for straightness, ±08 arcsec for angular error, and ±12 μm for linear displacement

Power supply control

Abstract: According to a first aspect, an uninterruptable power supply is provided. In one example, the uninterruptable power supply comprises a controller configured to provide a first current reference signal, the first current reference signal having a periodic waveform including a first half period and a second half period, each half period having a period end, the waveform comprising a substantially rectified sine wave modified such that a value of the rectified sine wave is equal to zero for a predetermined period of time prior to the period end of the second half period, a positive current loop control circuit configured to receive the first current reference signal and provide an output signal to the positive boost circuit, and a negative current loop control circuit configured to provide an output signal to a negative boost circuit.

Large eddy simulation of a pulsed jet in cross-flow

Abstract: This study quantifies the mixing that results from a pulsed jet in cross-flow in the near jet region. By large eddy simulation computations, it also helps to understand the physical phenomena involved in the formation of the pulsed jet in cross-flow. The boundary conditions of the jet inlet are implemented via a Navier–Stokes characteristic boundary condition coupled with a Fourier series development. The signals used to pulse the jet inlet are a square or a sine wave. A new way of characterizing the mixing is introduced with the goal of easily interpreting and quantifying the complicated mixing process involved in a pulsed jet in cross-flow flow fields. Different flow configurations, pulsed and non-pulsed, are computed and compared, keeping the root mean square value of the signal constant. This comparison not only allows the characterization of the mixing but also illustrates some of the properties of the mixing characterization.

High-frequency GaN diode-free motor drive inverter with pure sine-wave output

Abstract: Silicon-based power switching devices have improved dramatically since their inception decades ago. An impressive example: Si super-junction MOSFETs, such as CoolMOS FETs, broke the theoretical Si limit in the tradeoff between blocking voltage and resistance (Ref. 1). However, the large amount of minority charge in the body diode results in large reverse recovery losses in hardswitched bridge circuits—typical for motor-drive inverters. Thus insulatedgate-bipolar-transistors (IGBTs) are preferred in applications also requiring additional reverse-connected diodes for freewheeling current. With the relatively low-frequency bandwidth, IGBT-based inverters typically operate at 4–20 kHz and directly apply pulsewidth-modulation (PWM) power to the motor with the intention of utilizing the motor windings as energy storage inductances. The resultant voltage transients induce high stresses between motor windings and cause current spikes through motor bearings, leading to issues such as insulation breakdown and excessive bearing wear (Refs. 2–3). This paper demonstrates the use of wide-band-gap semiconductor GaN for hard-switched motor drive applications. The functionalities and frequency capabilities of the GaN high-electron mobility transistor (HEMT) eliminate the need for freewheeling diodes and allow a much higher PWM frequency, in turn enabling compact filters and resultant, spike-free, pure sine wave power output. Devices and Module The unit cell device used in this study is a GaN hybrid HEMT (Transphorm, Inc.). It incorporates a normally “off” low-voltage Si device at the input and a normally “on” high-voltage GaN HEMT at the output in cascode form (Fig. 1). The combined device is normally “off” with a gate threshold of + 2.1 V—typical at 1 mA drain current—and a drain leakage of 10 μA—typical at Vgs = 0 V and Vd = 600 V. The “on” resistance is

Electronic Scheme for Computing Inverse-Cosine and its Application to a GMR Based Angle Sensor

Abstract: This paper presents a new, simple but effective, electronic method to obtain inverse-cosine of an electrical variable. The proposed method is very useful for linearization of sensors whose output is a cosine or sine function of the physical quantity being sensed. The inverse-cosine of the variable is obtained by comparing it with a reference sinusoidal wave. The proposed method is easy to implement using electronic components. Using the new technique, a giant magneto-resistance-based angle sensor that provides an output linearly proportional to the angle being sensed has been developed, and the details are reported in this paper. A prototype of the angle sensor has been built, and the practicality of the new method has been tested successfully. The developed sensor provides a linear output for a range of 0° to 180°. The worst case error was found to be less than 0.35° for a range of 10°-170°.

A digital compensation bridge for R–C comparisons

Abstract: A novel automatic bridge linking capacitance and resistance has been developed. This bridge with only one 10?nF capacitance and one 10?k? resistance standard, operating at 1592?Hz, is implemented based on digital compensation techniques. The standards are all defined as four terminal-pair impedances. All voltages applied to the bridge are generated by a multiphase direct-digital-synthesis sine wave source, a special channel of which provided accurate phase and constant amplitude when the phase is changed. In contrast with the conventional quadrature bridge, a lot of inductive dividers and a series of balancing processes are avoided. Preliminary experimental results indicate a relative uncertainty of four parts in 107 is obtained and could be improved further.

Comparison of IPDA lidar receiver sensitivity for coherent detection and for direct detection using sine-wave and pulsed modulation

Abstract: We use theoretical models to compare the receiver signal to noise ratio (SNR) vs. average rate of detected signal photons for an integrated path differential absorption (IPDA) lidar using coherent detection with continuous wave (CW) lasers and direct detection with sine-wave and pulse modulations. The results show the coherent IPDA lidar has high receiver gain and narrow bandwidth to overcome the effects of detector circuit noise and background light, but the actual receiver performance can be limited by the coherent mixing efficiency, speckle and other factors. For direct detection, using sine-wave modulation allows the use of a low peak power laser transmitter and synchronous detection. The pulse modulation technique requires higher laser peak powers but is more efficient than sine-wave modulation in terms of average detected signal photon rate required to achieve a given receiver SNR. We also conducted experiments for the direct detection cases and the results agreed well with theory.

Phase Distortion to Amplitude Conversion-Based Low-Cost Measurement of AM-AM and AM-PM Effects in RF Power Amplifiers

Abstract: This work develops a simple, practical yet easily realizable method for low cost measurement of phase and amplitude distortions in radio frequency power amplifiers (RF PA). Amplitude-to-amplitude (AM-AM) and amplitude-to-phase (AM-PM) distortions are two significant distortion effects in PAs at high output power levels, causing out of band interference in the transmitted signal and bit errors in the received signal. Traditional measurements of amplitude and phase distortion in RF PAs require the use of expensive vector network analyzers. In this work, we propose the use of phase-to-amplitude conversion to develop a low cost and accurate test methodology for AM-AM and AM-PM measurement using simple load board test circuitry along with software based difference generation and peak detection mechanisms. Using either simple sine wave stimulus with power sweep or a single amplitude modulated RF stimulus, both distortion effects can be measured with high accuracy for nominal devices as well as over process and voltage variations, while allowing significant reduction in test cost.

Influence of Parallel Paths on Current-Regulated Sine-Wave Interior-Permanent-Magnet Machines With Rotor Eccentricity

Abstract: The behavior of rotor eccentricities in current-regulated interior-permanent-magnet machines is investigated The study focuses on two typical topologies of significant industrial relevance: machines with distributed windings with two slots per pole and phase and motors with concentrated coils and three slots per pole pair The effect of stator-winding parallel paths is examined for both cases Coil and terminal electrical quantities and radial forces were simulated using finite-element analysis Unbalanced operation, where the currents are not equal in parallel phase connections due to eccentricity, is also investigated Experimental measurements of electrical quantities and forces on motors with static eccentricity are carried out using two special test setups The experimental measurements validated the simulation results

Accuracy of the Normalized Frequency Estimation of a Discrete-Time Sine-Wave by the Energy-Based Method

Abstract: This paper investigates the effect of algorithm error, spectral interference, and additive wideband noise on the accuracy of the normalized frequency estimation provided by the Energy-Based Method (EBM) in the case of a discrete-time sine-wave. The statistical efficiency of the EBM estimator with respect to the unbiased Cramer-Rao Lower Bound (CRLB) is determined. The accuracy of the derived expressions is confirmed by means of computer simulations. Moreover, the expression of the rms error of the normalized frequency estimate is derived. Finally, the performance of the normalized frequency estimators provided by the EBM and other state-of-the-art methods are compared by means of both simulations and experimental results.

Noise Power Estimation by the Three-Parameter and Four-Parameter Sine-Fit Algorithms

Abstract: This paper analyzes the performance provided by the three-parameter sine-fit (3PSF) and the four-parameter sine-fit (4PSF) algorithms when estimating the noise power of a sine wave corrupted by a white Gaussian noise. In the former case, the frequency parameter is extracted from the available data by using the interpolated discrete Fourier transform (IpDFT) method. The related procedure is called the 3PSF-IpDFT algorithm. Simple expressions for the expected sum-squared fitting and the expected sum-squared residual errors are derived for both the 3PSF and 4PSF algorithms, which agree with previously published results. These expressions show that the sum-squared fitting error of the 4PSF algorithm is smaller than the corresponding value associated with the 3PSF algorithm when the uncertainty of the sine-wave frequency employed by the latter algorithm is greater than the related Cramer-Rao lower bound. From this point of view, the 4PSF algorithm outperforms the 3PSF-IpDFT algorithm. However, since the frequency estimator provided by the IpDFT method is consistent, the sum-squared fitting error associated with both the 3PSF-IpDFT and 4PSF algorithms can be made negligible as compared with the sum-squared residual errors, when the number of analyzed samples is large enough. Moreover, several simulation results show that the 3PSF-IpDFT algorithm requires a much lower computational effort than the 4PSF algorithm. Therefore, it represents the best alternative when estimating the noise power of a sine wave embedded in white noise.

Analytical metrological characterization of the three-parameter sine fit algorithm.

Abstract: The three-parameter sine fit is a well known algorithm used in IEEE standard 1241-2000 for ADC characterization to estimate sine wave parameters from recorded data. An analytical metrological characterization of that algorithm is carried out in terms of its design parameters, namely the sampling rate and the number of samples. Optimal and sub-optimal parameters' sets are found. Focusing on the amplitude estimation, an approximated statistical characterization of the second order is given in the most general case of zero mean additive noise, whereas the exact probability density function is found for the optimal set of algorithm parameters in the case of additive white Gaussian noise. In this particular case, the frequency behavior of the algorithm is fully analyzed and the exact frequency response of the amplitude is also found. An approximated expression that is easier to use is then presented and discussed. Simulation results for a single set of parameters are presented in order to graphically illustrate the analytical results.

Quadrature demodulation with synchronous difference for interferometric fiber-optic gyroscopes

Abstract: We propose a novel method of quadrature demodulation with synchronous difference for suppressing noise in interferometric fiber-optic gyroscopes (IFOGs). For an IFOG with sine wave phase modulation, an in-phase result and a quadrature result are obtained simultaneously by coherent detection. Eigenfrequency modulation is used and a phase shift of 45° is set between the modulation signal and the reference signal, so that two results have the same expectation of amplitude but with opposite signs. A synchronous difference procedure is carried out for output, in which signals are added up and common noise between two results is eliminated. Theoretical analysis and experimental results show that both short term noise and long term instability of the IFOG are reduced by this method. In experimental comparison with the traditional demodulation method on the same IFOG with a 1982 m fiber coil, this method reduces the bias drift from 0.040°/h to 0.004°/h.

Signal processing device, method, and program

Abstract: The present technology relates to a signal processing device, a method and a program which allow for the acquisition of sound with higher acoustic quality when decoding a sound signal. An envelope information generating unit (24) generates envelope information indicative of an envelope shape for the high-frequency components of a sound signal to be encoded. A sine wave information generating unit (26) detects a sine wave signal from the high-frequency components of a sound signal, and generates sine wave information indicative of the start position of the appearance of the sine wave signal. An encoded stream generating unit (27) multiplexes the envelope information, the sine wave information and the low-frequency components of the encoded sound signal, and outputs an encoded stream acquired thereby. Hereby, the receiving side of the encoded stream can estimate with higher accuracy the high-frequency components including the sine wave signal from the envelope information and the sine wave information. The present invention can be applied to a signal processing device.

Drive device, electronic device, and drive control program

Abstract: Provided is a drive device comprising: a storage unit for storing waveform data for a drive signal that, when the resonance frequency of an actuator is designated as (f0), has the phase thereof shifted by π/2 from a sine wave that satisfies [frequency (f1) = m/n×(f0)] (m and n are naturals numbers, and m ≠ n), and that excites the actuator m times and stops excitation of the actuator outside of the central point of the amplitude; and a drive processing unit that reads the waveform data stored in the storage unit and outputs a drive signal corresponding to the waveform data to the actuator.

ITO (Indium Tin Oxide) electrical characteristic detecting method and detecting system of capacitance type touch screen

Abstract: The invention relates to an ITO (Indium Tin Oxide) electrical characteristic detecting system of a capacitance type multipoint touch screen, which comprises an inductive electrode array circuit board, a sine wave phase measuring circuit and a sine wave signal control and data processing circuit, wherein the inductive electrode array circuit board is used for carrying a detected touch screen and respectively transmitting sine waves to all ITO circuit layers of the touch screen during the detection, the sine wave phase measuring circuit is used for measuring a phase difference between an input signal and an inducing signal; the capacitance field distributing condition between all ITO circuit layers and an inductive electrode and between two adjacent ITO circuit layer is obtained by adjusting the output of sine wave frequency; and that whether the electrical characteristic of an ITO line and a silver lead is favorable or not can be judged according to the capacitance field distribution, thereby realizing further detection of the yield of the touch screen and having greater popularization and application value.

The spectrum of travelling wave solutions to the Sine-Gordon equation

Abstract: We investigate the spectrum of the linear operator coming from the sine-Gordon equation linearized about a travelling kink-wave solution. Using various geometric techniques as well as some elementary methods from ODE theory, we find that the point spectrum of such an operator is purely imaginary provided the wave speed $c$ of the travelling wave is not $\pm 1$. We then compute the essential spectrum of the same operator.

A Novel Method of Ambient Interferences Suppressing for In Situ Electromagnetic Radiated Emission Test

Abstract: A measurement method for adaptive interference suppression in in situ radiated emission test is proposed. First, the method obtained multichannel data to achieve the signal directions of arrival from equipment under test (EUT) and interference sources by the spatial spectrum estimation technique based on the multiple signal classification algorithm. Second, broadband minimum variance distortionless response (MVDR) beamforming algorithm combined with short time Fourier transform (STFT) was taken to form the beam pattern null traps in the directions of interferences, thus realizing the suppression on interferences. The factors affecting the accuracy of spatial spectrum estimation and the angular resolution of beamforming were discussed, and the suppression effects on different kinds of interferences were simulated. The simulation results show that the method can suppress multiple interferences, which are either narrowband or broadband, continuous or transient, and avoid little distortion to the time-frequency characteristics of EUT signal simultaneously. The method performance was evaluated by experiments. The results show that sine wave and pulse modulation interferences can both be suppressed remarkably, which proves the effectiveness and advantage of this new method for electromagnetic compatibility in situ test.