Search

Precision contact probes have a huge demand in industrial manufacturing due to their high accuracy. However, the passive measurement mode of the existing probe easily causes wear of the probe ball and loss of accuracy during continuous contact scanning. In this paper, a PZT(piezoelectric actuators)-driven flexible probe is proposed with the dynamic time-domain function of the system response from low frequency to high drive frequency. The low-frequency measurement mode is established based on the linear response of the triangle wave. In order to avoid the trajectory nonlinearity of the stylus ball driven by PZT, the nonlinear mapping of the PZT hysteresis model is constructed by the BP neural network, and the linearly weighted particle swarm optimization (PSO) algorithm is used to realize the suppression of the response nonlinearity. Finally, the measurement experiment of the PZT-driven probe is conducted to reveal the measurement characteristics of low-frequency mode as well as measurement capability compared with commercial sensors.

The combination of synthetic aperture radar (SAR) with unmanned aerial vehicles (UAVs) is attractive for acquiring high-resolution images without the restrictions of time and weather. However, because UAVs are lightweight and small in size, the UAV SAR system is very sensitive to turbulence, resulting in serious trajectory deviations and remaining residual motion errors (RMEs), such as residual range cell migration (RCM) and aperture phase errors (APEs). In this paper, a novel motion compensation (MoCo) strategy is developed based on the symmetric triangle linear frequency modulated continuous wave (STLFMCW) signal. The STLFMCW signal model is first presented, which reveals the relevance between the positive-negative frequency modulations and motion errors. The residual RCMs and relative phase errors are estimated directly through the phase differential interferometry of up-ramp and down-ramp chirp signals, instead of the traditional approach of relying on the range-shift gradient of adjacent range profiles. The proposed approach is independent of conventional prominent point processing (PPP) and calculates the range deviation to avoid the accumulation of errors, thereby achieving high precision and efficiency. Experiments based on simulated and measured data sets validate the proposed approach.

In this study, analternative input shaping method is proposed to reduce residual vibration tothe pulse width modulation delivered flexible systems. An input shaping methodis proposed which works robust even system parameters such as system naturalfrequency and damping ratio are not known or wrongly estimated. It is possibleto generate unity magnitude input shaper with high number of pulses within thismethod. This input shaper can eliminate or reduce residual vibration. Timelocations have an importance on performance of input shaping techniques. Timelocations of impulses are found by intersection points of reference motionprofile and triangle wave. This proposed method is compared with well-knownzero vibration method, performance characteristics of proposed input shapingtechnique and diagrams about the system response are demonstrated. Furthermore,it’s shown that proposed input shaping method works robustly even travellingtime is reduced., Bu çalışmada, darbe genişlik modülasyonu ile sürülenesnek sistemlerde oluşan artık titreşimin azaltılması amacıyla, alternatif birgirdi şekillendirme metodu sunulmuştur. Sistem doğal frekansı ve sönüm oranıgibi parametrelerinin tam olarak bilinmemesi ya da hatalı tahmin edilmesidurumunda dahi gürbüz bir girdi şekillendirme metodu oluşturulmaya çalışılmıştır. Birim genlik kullanılarak elde edilen girdişekillendirme metoduyla çok sayıda darbeye sahip girdi şekillendiriciüretilebilir ve bu girdi şekillendirici sistemdeki artık titreşimi yokedebilmektedir ya da azaltabilmektedir. Girdi şekillendirme tekniklerinde,darbe zamanları tekniğin performansını belirlemektedir. Önerilen metotta darbezamanları referans hareket profilinin, değişken frekanslı üçgen dalgalarlakesiştirilmesiyle bulunur. Önerilen metot, çok bilinen sıfır titreşim metoduile karşılaştırılıp, sunulan girdi şekillendirme metodunun performanskarakteristiği ve sistemin cevabıyla ilgili grafikler sunulmuştur. Ayrıca girdişekillendirme tekniğinin, seyahat süresinin daha kısa olması istenilendurumlarda da gürbüz olarak çalıştığı görülmektedir.

The difficulty of adding external excitation and the asynchronous data collection from the industrial robot operation limited the online parameter identification of industrial robots. In this regard, this study proposes an identification method that only uses the amplitude of the frequency response function (FRF) of the system to identify robot joint torsional stiffness and dynamic parameters. The error criterion function shows that this method is feasible and comparable to applying the complete frequency response for identification. The Levenberg–Marquardt (L-M) algorithm is used to find the global optimal value of the error criterion function. In addition, an operational excitation method is proposed to excite the system. The speed profile is set as a triangle wave to excite the system using rectangular wave electromagnetic torques. The simulation results show that using the amplitude of the FRF to identify parameters applies to asynchronous data. The experiments on a single-degree-of-freedom articulated arm test bench show that the motion excitation method is effective, and both stiffness and inertia are identifiable.

The purpose of this study was to investigate an influence of vibration waveform on magnetic resonance elastography (MRE). MRE is an innovative imaging technique for the non-invasive quantification of the elasticity of soft tissues through the direct visualization of propagating shear waves in vivo using a special phase-contrast magnetic resonance imaging sequence. Since the elasticity of soft tissue calculates from the wavelength of propagating shear waves, it is necessary to propagate sine-wave-shape shear wave at the target soft tissue. However, due to the various factors; i.e. overload of vibration generator, poor contact between imaging object and vibration pad, etc.; it may be difficult to generate a simple sine wave. This work was focused on change vibration waveforms; i.e. square wave, triangle wave, saw-tooth wave; which is induced by the various factors. Phantom experimental results demonstrated that when square and saw-tooth waveforms of 25 Hz vibration frequency, into the phantom, the waveform of propagating wave was not similar to sine waveform. It may influence on the MRE that in case of the waveforms has low frequency and square or saw-tooth like waveforms.

The paper presents a new experimental method of the magnetic hysteresis loop investigation and the constructed measurement instrument. The principle of operation is to mix two magnetic fields: the first of these fields has a very low amplitude, a shape of sine wave (AC bias) and the frequency range order of 10–104 Hz. The second field has a very low frequency (order 10−2 Hz), a high amplitude and forms approximately a triangle wave. The presented, dedicated system is different in comparison to commonly used hystographs and it consists of coreless coils only. The measurement method gives the opportunity of obtaining more detailed measurements of the initial cycles in the material magnetizing process. In a special case, the magnetic field strength changes in the B(H) curve can be stopped at any operating point and then it is possible to investigate local properties using AC bias field for various frequencies. The results revealed a successive displacement of the hysteresis loop and approaching to the steady state position., Magnetic properties, Measurement instrument, Hysteresis loop, Magnetic field interference.

Energy is the foundation of economic development and technological development. Facing the present situation of non-renewable energy decline, wind power generation has been developed rapidly. However, the problem of unstable output voltage of wind power generation due to unstable wind speed needs to be solved, and traditional solutions cannot make the generated electric energy meet the national standards for grid-connected and off-grid operation. In this paper, the electric energy generated by wind turbine is rectified by bridge rectifier circuit and using large capacity capacitor filtering to generate DC with flat waveform. Then, using SPWM inversion technology, the normal rotation wave with the same frequency as the power grid is used as the modulation wave and according to the required voltage amplitude, and the triangle wave with appropriate duty ratio is calculated by SPWM smoothing control theory as carrier wave. Subsequently, accurate filtering is carried out and grid-connected and off-grid operation is carried out through the self-aligning device. Finally, with the help of MATLAB simulation platform, the wind turbine is simulated to work under different wind conditions, and whether the generated electric energy meets the grid-connected and off-grid operation standards is judged, which further determines the reliability and authenticity of the theory.

Porous anodic alumina (PAA) films with periodically modulated pore diameters are prepared by cyclic anodization of Al in a 0.6 M H3PO4 solution at room temperature. Studies have demonstrated that the oscillating current signals have an important effect on the structures of PAA films. Scanning electron microscopy (SEM) images of the PAA film show that when the positive triangle wave current signal is applied, with the increase in the maximum current value, PAA gradually exhibits a symmetrically modulated pore diameter structure, and part of the pores generates slub-like branches. When the maximum current value is 60 mA, the effect of modulation on the pore diameter is the most obvious and the UV reflectance spectrum shows the lowest reflectivity. A sawtooth wave current signal will cause the generation of a V-shaped structure at the junction of adjacent oxide layers. This work provides important guidance for regulating the structure of PAA by changing the current signal.

Molecular dynamics simulations were performed to investigate the cyclic deformation of magnesium single crystalline nano-pillars in the first three cycles. To study the tension–compression asymmetry, two symmetric uniaxial cyclic loading paths (applied strain amplitude = 10%) were employed, i.e., a triangle wave loading path started by tension and a triangle wave loading one started by compression. The influence of crystalline orientation on the cyclic deformation of magnesium nano-pillars was studied by changing the angle θ between the loading direction and the c-axis of the nano-pillars (e.g., 0°, 45°, and 90°). Under the cyclic loading path started by tension, the full deformation process in each cycle is controlled by twinning- detwinning-pyramidal slip-retwinning at θ = 0° with significant tension–compression asymmetry observed, basal slip + twinning-detwinning-basal slip + retwinning at θ = 45° without any tension–compression asymmetry, and double twinning-detwinning-retwinning-detwinning at θ = 90° with significant tension–compression asymmetry. Under the cyclic loading one started by compression, on the other hand, the deformation process is dominated by pyramidal slip-twinning-detwinning at θ = 0°, basal slip-twinning-detwinning-retwinning at θ = 45°, and prismatic slip-double twinning-detwinning in the first two cycles and twinning-detwinning-retwinning in the third cycle at θ = 90°, while tension–compression asymmetry is observed in the cases at θ = 0° and 90° only due to different deformation modes in the tension and compression stages. Especially, for the loading path started by compression at θ = 90°, cyclic hardening is seen in the tension stage, but softening is observed in the compression stage only in the third cycle due to the change of deformation modes. The current work provides new insights for understanding the mechanical property of Mg crystals subjected to a cyclic loading.

Shock-induced spall in initial defect-free single crystal SiC is investigated using molecular dynamics (MD) simulation. Three shock pulses ranging from triangle to square are adopted to study the effects of pulse duration on spallation. The evolution of micro-structure and damage are analyzed in detail. Shock-induced plasticity is found to include deformation twinning and structure changes from 4 to 5 fold coordination number. These deformations disappear upon unloading causing numerous defects. Morphology of spallation is found to depend on these damage strongly. Furthermore, the spall strength obtained from free surface velocity and bulk are compared. Triangle pulse yields a higher value in the spall strength calculated from free surface velocity, while square pulse enjoys a similar result in both methods. Moreover, the theoretical total spall thicknesses are derived basing on the theory of spallation. The prediction of the total spall thicknesses are made using the stress waveform right before reflection and the spall strength. A good agreement between the simulation and the prediction is found in triangle wave.

Fifteen level single phase multilevel inverter is constructed using power circuit consist of 7 MOSFETs, seven independents DC sources, seven diodes, and an H-Bridge circuit. Switching method used in this MLI is sinusoidal pulse width modulation (SPWM) multicarrier where the reference wave in the form of a sinusoidal wave. Multicarrier SPWM circuit is designed using electronic components such as Op-Amp that used as a comparator and some logic gates such as AND, OR and NOT gate to trigger S1, S2, S3, S4, S5, S6, S7, and H-Bridge circuit. Carrier waves used in this MLI modified from the triangle wave that having a frequency into carrier waves without frequency (DC sources) where THD that generated into 5.502%. While methods that use frequency such as Phase Disposition PWM (PD PWM), Phase Shift PWM (PS-PWM), and Carrier Overlapping PWM (CO PWM) that produces THD greater than the proposed method, this system was simulated using PSIM software.

Time-division analog multiplier is the measurement core of reference electrical energy meter. The measurement accuracy of time-division analog multiplier is improved by using signal conversion and phase lock technologies and symmetrical triangle wave generator. Signal conversion and phase-locked technology will be measured signal and triangle wave generator of time division multiplier correlation processing, to achieve triangle wave generator of time division power multiplier and measured signal full cycle synchronization. A symmetrical triangle wave generator with reference level accuracy is developed, which makes the measurement accuracy of time-division analog multiplier reached 20ppm and meet the measurement requirements of 50ppm reference electrical energy meter.

This study deals with the performance analysis of Pulse Width Modulation (PWM) scheme for three phase voltage source inverter though intermingling of multiple carriers. The proposed PWM scheme using two groups of carriers (inverted Sine wave and Triangle wave), each group having carrier and its 90° shifted. The arbitrary selection of these carriers is based on the linear feedback shift registers value ('0' or '1'). This random carrier selection is serving to improve the spectral quality of the output of the inverter. This improved waveform has been derived from third harmonic injected sine PWM technique. Simulation results confirm the effectiveness of the proposed scheme in providing very less harmonic noises with minimum distortion and satisfactory fundamental component. This study also shows the implementation compatibility of the work with Field Programmable Gate Array environment.

The main purpose of the thesis is to make a control unit where different models can be tested with a number of motors, sensors, indicators, control devices which are used by Fischertechnik in training models. This work observes different types of speed motor control and investigates most useful method that could be implemented at the PLC Lab. It would be very useful to simulate separated parts of the unit by using different software and compare actual results with theoretically expected results. All the results must be realistic and simply implemented in a real lab. Obtained circuit should be implemented in board layout after succeed simulations and checked for safety using in future. Measured signal, voltage level on each node and behavior of motors should be similar to the theoretical results

Thermo-acoustic (TA) transducers are generation of sound speakers without any mechanical vibration system which exhibit an extremely wide frequency response range. In this paper, acoustic field responses to broadband input signals applied to both free-standing and nano-thinfilm-substrate thermo-acoustic devices are developed theoretically by using the Fourier transformation. A series of signals, including single-frequency signal, square root signal, periodic triangle wave signal, and periodic rectangular pulse signal, are applied to these TA devices in simulations and the acoustic pressure responses are investigated. The reproducibility of input signals is predicted. The single frequency results show good agreement with previously published experimental results. Alternative methods for reproducing the original signals with small distortion and low power consumption are introduced. The excellent performance of the TA devices on broadband signal responses will provide a design approach for sound parametric array and underwater communication equipment.

How speech is separated perceptually from other speech remains poorly understood. Recent research indicates that the ability of an extraneous formant to impair intelligibility depends on the variation of its frequency contour. This study explored the effects of manipulating the depth and pattern of that variation. Three formants (F1+F2+F3) constituting synthetic analogues of natural sentences were distributed across the 2 ears, together with a competitor for F2 (F2C) that listeners must reject to optimize recognition (left = F1+F2C; right = F2+F3). The frequency contours of F1 − F3 were each scaled to 50% of their natural depth, with little effect on intelligibility. Competitors were created either by inverting the frequency contour of F2 about its geometric mean (a plausibly speech-like pattern) or using a regular and arbitrary frequency contour (triangle wave, not plausibly speech-like) matched to the average rate and depth of variation for the inverted F2C. Adding a competitor typically reduced intelligibility; this reduction depended on the depth of F2C variation, being greatest for 100%-depth, intermediate for 50%-depth, and least for 0%-depth (constant) F2Cs. This suggests that competitor impact depends on overall depth of frequency variation, not depth relative to that for the target formants. The absence of tuning (i.e., no minimum in intelligibility for the 50% case) suggests that the ability to reject an extraneous formant does not depend on similarity in the depth of formant-frequency variation. Furthermore, triangle-wave competitors were as effective as their more speech-like counterparts, suggesting that the selection of formants from the ensemble also does not depend on speech-specific constraints.

A class D amplifier is one in which the output transistors are operated as switches. When a transistor is off, the current through it is zero and when it is on, the voltage across it is small, ideally zero. Thus the power dissipation is very low, so it requires a smaller heat sink for the amplifier. Class D amplifier operation is based on analog principles and there is no digital encoding of the signal. Before the emergence of class D amplifiers, the standard classes were class A, class AB, class B, and class C. The classic method for generating signals driving a transistor MOSFET is to use a comparator. One input is driven by an incoming audio signal, and the other by a triangle wave or a sawtooth wave at the required switching frequency. The frequency of a triangular or sawtooth wave must be higher than the audio input. MOSFET transistors work in a complementary manner that operates as a switch. Triangle waves are usually generated by square waves fed to the integrator circuit. So the main part of processing audio signals into PWM (Pulse Width Modulation) is the integrator and comparator. In this paper, we will discuss the work of a class D amplifier system using the summing integrator method as its main part.

The function signal generator uses the integrated circuit IC8038 for signal generation. After filtering, signal amplification, relay network signal strobe, and resistor divider, it outputs square wave, triangle wave and sine wave with adjustable amplitude ranging from 0V to 10V and adjustable frequency ranging from 100Hz to 20KHz. The relay network is controlled by the single-chip STC12C5A60S2, and the signal selection and output are controlled by the single-chip microcomputer, too. The function signal generator can generate triangular, square and sinusoidal signals from 100HZ to 20KHZ. It has the characteristics such as low cost, good signal quality and easy operation, thus improving the intelligence level of the signal generator.

In this work, a Wien Bridge Oscillator and a Triangle Wave Oscillator were used to obtain a 40 KHz sine wave and a 400 KHz triangular wave respectively. A modified pulse using a comparator circuit was obtained to control the laser transmission circuit and to send the modified laser pulse to the photodiode receiving circuit in any distance. The original sine wave (40 KHz) was then retrieved to be used in medical, industrial, physical and military applications.

Through introducing two piecewise-linear triangular wave functions in a three-dimensional spiral chaotic Colpitts oscillator model, a four-dimensional grid multiscroll hyperchaotic system is constructed. Interestingly, by adjusting a build-in parameter in a variable of one triangle wave function, the control of the gradient of the multiscroll grid is achieved. Whereas by deploying the zero points of the two triangular wave functions to extend the saddle-focus equilibrium points with index-2 in phase space the scroll numbers do not only increase along with the number of turning points, but they can also generate arbitrary multiples of products. The basic dynamical behaviors of the proposed four-dimensional multiscroll hyperchaotic system are analyzed. Finally, the hardware experimental circuit is designed and the interrelated circuit implementation is realized. The experimental results are in agreement with both theoretical analyses and numerical simulations, which verify the feasibility of the design methods.

The aim of this study is to research maximum harvesting energy by the optimal input wave condition. The voltage characteristics of the PZT bimorph were investigated in terms of the sine wave, triangle wave and square wave according to frequency range 0~70Hz. It was found that the square wave compared with a triangular wave or square wave was showed the higher output energy. PZT bimorph was mechanically vibrated by solenoid coil experiments, which revealed two voltage peak mode according to frequency. Maximum voltage at second vibration frequency 28Hz demonstrated that the generated DC voltage was proportional to the tip displacement of the bimorph and the phase difference between the input frequency and bimorph vibration frequency was 90 degree. It was expected that optimized design to harvest a much higher energy level from lower frequency vibrations.

By using the dynamical system method to study the 2D-generalized Benney-Luke equation, the existence of kink wave solutions and uncountably infinite many smooth periodic wave solutions is shown. Explicit exact parametric representations for solutions of kink wave, periodic wave and unbounded traveling wave are obtained.

This paper is concerned with optimal reference tracking control problem for discrete time 1-DOF/2-DOF systems. It is well known that l2 norm of an error, which is defined by difference between an output and a reference, does not turn zero for all possible controllers when plant is given as a non-minimum phase system. Purpose of this research is to derive closed-form expression of the optimal value of l2 norm of the error and its controller. The references for tracking are e.g. step, sine, impulse train, triangle wave and linear combination of these signals. Therefore, we can handle various signals as a reference. Moreover, our results can also characterize impact of the relative degree of plant. Those effectiveness are shown by numerical examples.

We consider the semilinear Duhem model and develop an identification method for rate-independent and rate-dependent hysteresis. For rate-independent hysteresis, we reparameterize the system in terms of the input signal, so that the system has the form of a switching linear time-invariant system with ramp-plus-step forcing. For rate-dependent hysteresis, the system can be viewed as a switching linear time-invariant system for triangle wave inputs. Least-squares-based methods are developed to identify the rate-independent and rate-dependent semilinear Duhem models

The paper design a Virtual Signal Generator based on Virtual Instrument,which can produce continuous adjustable amplitude and frequency signal .It's contains of the most basic three waveform: sine wave, pulse wave and triangle wave. We design the signal generator by LabVIEW. Data acquisition is NIUSB-6009. By the measurement we can seen from function to output signal parameters of the virtual signal generator are similar as the results of actual measurement.

A disposable cyclic voltammetry (CV) tag is printed on a plastic film by integrating wireless power transmitter, polarized triangle wave generator, electrochemical cell and signage through a scalable gravure printing method. By proximity of 13.56 MHz RF reader, the printed CV tag generates 320 mHz of triangular sweep wave from +500 mV to −500 mV which enable to scan a printed electrochemical cell in the CV tag. By simply dropping any specimen solution on the electrochemical cell in the CV tag, the presence of solutes in the solution can be detected and shown on the signage of the CV tag in five sec. 10 mM of N,N,N′,N′-tetramethyl-p-phenylenediamine (TMPD) was used as a standard solute to prove the working concept of fully printed disposable wireless CV tag. Within five seconds, we can wirelessly diagnose the presence of TMPD in the solution using the CV tag in the proximity of the 13.56 MHz RF reader. This fully printed and wirelessly operated flexible CV tag is the first of its kind and marks the path for the utilization of inexpensive and disposable wireless electrochemical sensor systems for initial diagnose hazardous chemicals and biological molecules to improve public hygiene and health.

The push-pull power boost and full-bridge inverter levels change in the control circuit, the first-stage booster circuit using SG3525 chip push-pull control, closed loop feedback; inverter part EG8010 complete SPWM modulation driver chip IR2110 be full-bridge inverter; after level output is sampled using a current transformer feedback, a double feedback loop, increasing the stability of the power; on protection, with output overload, short circuit protection, overcurrent protection, load protection and multiple protection features circuit, and enhance the reliability and security of supply; inverter power dependence of the clean, efficient, renewable solar energy resources, the use of solar photovoltaic cells lithium battery charging plate board, pre-24V lithium battery voltage through DC-DC conversion is about 400V DC high voltage, after the class by a full-bridge DC-AC circuit 400V voltage controlled by SPWM inverter is 220V, 50Hz AC sine standards for the use of electrical appliances. Introduction According to "China Renewable Energy Development Strategic Plan (2006-2020)" (draft) pointed out that China's future generation capacity planning objectives: by 2020 the total installed capacity of renewable energy 1.21×108KW, which total installed solar PV capacity up to 10× 105KW[1]. Research shows that one year to the total solar radiation on the earth's surface and 130 trillion tons of coal equivalent energy, solar total reserves can be called the greatest potential for energy development in the world today [2]. Under the strong pull "Bright Project" pilot projects and "power to the villages," engineering projects and other countries of the world PV market, the rapid development of China PV industry [3]. As the solar cell or battery is a DC power supply, when the load is an AC load, the inverter converts DC power into AC power is essential equipment. The so-called inverter, the rectifier means is the inverse transformation, the opening through the semiconductor power switching devices on and off action, the DC can be converted into AC power, a power conversion transpose [4]. Domestic power inverter by using frequency conversion method primarily transformation, frequency inverter is first transformed to produce 50Hz AC signal, and then use frequency booster produces 220V AC. This inverter is a simple structure, reliable operation, but this inverter is bulky, heavy, noisy, high prices, but also to be further improved efficiency [2][4]. With the development of power inverter and power electronics devices, high frequency inverters transform the way gradually inverter market. High frequency inverter power is transformed by high-frequency DC-DC conversion technology, low-voltage DC into high frequency low voltage DC, and then after a high-frequency step-up transformer is rectified into HVDC, HVDC if the sine transform, you can get 220V / 50Hz sine wave AC. This inverter control more links, circuit complexity, but because the use of high-frequency transformation, therefore, small size, light weight, low noise, high efficiency, renewable energy is the product of choice for power generation system [5][6]. Basic square wave inverter circuit is simple, but the output voltage waveform harmonic content is too large, that THD (current harmonic distortion) is too large; phase inverter circuit for multiple overlay THD improved, but the circuit complexity; and based on the positive selection of new single-chip pulse width modulation inverter technology to make up for these shortcomings, not only International Conference on Intelligent Systems Research and Mechatronics Engineering (ISRME 2015) © 2015. The authors Published by Atlantis Press 1419 harmonics decreases, the circuit is simple, controlled diversification, but also real-time dynamic output feedback, closed-loop control greatly improves the operation of inverter performance. Principle and Calculation A pulse width modulation inverter PWM (Pulse-Width Modulation) is made of a reference wave (typically a sine wave, a trapezoidal wave and may also use a square wave, etc.) to "modulation wave" (Modulation Wave), to N times positive modulation wave frequency triangle wave (sometimes with sawtooth) as "carrier" (Carrier Wave)[7]. Since the triangular wave or a sawtooth waveform of the vertical width of the linear change so that it intersects with the modulated wave, it is possible to obtain a set of equal amplitude and the width of the rectangular pulse train is proportional to the function value of the modulated wave is equivalent to the modulation wave, species replaced by analog switch, on-off control of the inverter switching tubes, the direct current into alternating current technology called pulse width modulation technology. If the modulation wave sine wave, triangle wave or sawtooth carrier, and called this modulation is sinusoidal pulse width modulation, the purpose is to generate SPWM signal. Fig.1, a half sine wave N decile, can be seen as connected to each other the N pulse sequence, the width equal, but unequal amplitude, instead of using a rectangular pulse, amplitude, ranging from broad, overlapping midpoint, Impulse (narrow pulse area) equal to the duty cycle of the pulse series by sine law to change, so you can use the equivalent rectangular pulse to pulse being selected, and this is called SPWM rectangular pulse waveform. When the sine is maximum, the maximum pulse width, and the minimum interval between pulses, whereas, when the sine value is small, the pulse width is small, and the interval between pulses is greater, so that a waveform can SPWM the load current of the higher harmonic component is reduced greatly. Fig.1 Sine waveform equivalent rectangular pulse sequence Determines the reference wave frequency r f is the output frequency o f , the number of pulses per half cycle determined by the carrier frequency c f . Changed by changing the reference sine wave amplitude modulation, output voltage peak from 0 to max o U (maximum output pulse amplitude). If the j-th pulse width j θ , effective value of the output voltage can be obtained: ( )/2 2 outef max max ( )/2 1 2 U ( t) 2 p j p o o j p p U d U p θ p θ θ ω p p + − = = = ∑ ∫ (1) Where p is the number of pulses per half cycle; j θ is j-th for the first pulse width. The output voltage of the Fourier series expansion for: ( ) ( ) 0 1 cos sin n n n U t A n B n ωθ ωθ ∞ = = + ∑ (2) The output voltage can be calculated by the formula on the Fourier series coefficients: ( ) 1 2 sin sin p n j j j j E A n a n n θ a p =   = + −   ∑ (3) ( ) 1 2 cos cos p n j j j j E B na n n a θ p =   = − +   ∑ (4)

The fluidization behaviors of ultrafine particles were investigated in an acoustic fluidized bed with one type of micron particles and two types of nanoparticles. With the assistance of sound wave having low sound frequency and high sound pressure level, the micron and nanoparticles can be fluidized smoothly with fluidization behaviors similar to those of Geldart Group A particles. It has been found that increasing sound frequency leads to a reduction in minimum fluidization velocity, and then to an increase in minimum fluidization velocity. At the same sound frequency, the fluidization quality of nanoparticles improves significantly with increasing sound pressure level (100–103.4 dB). In addition, a thorough investigation indicates that sound wave configuration have an influence on fluidization process of ultarfine particles. Experiments show that both Sine wave and Triangle wave can enhance fluidization quality of ultarfine particles.

In the context of analog BIST for ADC, this paper presents two structures for the internal generation of a linear signal used with the histogram-based test technique. All of these structures use wide-swing current mirrors and an original adaptive system to make the generators less sensitive to process variations. The first structure allows us to generate high quality ramp signal. In a second step, a very high accuracy triangle-wave signal generator is presented in order to improve the equivalent linearity of the generated analog test signal.

It is very important in the industrial field to examine mechanical and fatigue life properties of small materials such as thin films. Some kinds of test equipment and methods for such small material have been developed. For example, there are simple and compact tensile testing devices that use a DC motor as the actuator, and also micro indentators, which measure material properties by pushing a diamond indentator on the surface. However, it is still difficult to conduct a fatigue test with complex waves like a triangle wave by the above testers. In this study, a small fatigue testing device, in which a piezo electric ceramic is applied as the actuator, was produced as a trial for measuring a tensile strength and fatigue life properties of a small material. Through our tests, it was found that the small fatigue testor which was developed here is effective for small specimens. Results showed that a yield stress and tensile strength for our film material was much higher than for SUS304 bulk material, which we had tested previously. The fatigue life was also much higher than for the bulk.

The crystallographic properties and ferroelectric state of BZT multilayer films which deposited on Si (100) substrate was studied in this work. XRD pattern peaks show that BaZr0.1T0.9O3 and BaZr0.08Ti0.92O3 are found wellcrystallized at 800 o C for 3 hours corresponding to vary annealed temperature. The BZT multilayerfilms are identified as tetragonal-perovskite structure. This is supported by the existence of a measured hysteresis loops which the instrument and the system is on own works.Fundamentally of theoretical in physics field, the SawyerTower Circuit has been concluded to ferroelectric phenomenon analysis on sample of material with experimental result as P-E hysteresis curve.The Sawyer-Tower Circuit method was used to measure the electrical polarization with triangle wave signal at fixed frequencies 50 Hz( = 0), and maximum electrical field (Emax) were injected continuously at the 40 Volt/cm. The system plotted the electrical field with respect to polarization (P-E curves), include its value. This data was used as a parameter for determining electric property of material. These results have shown the maximum value of electric field which could be used as measurement parameter. The highest maximum polarization, 34.12 µC/cm 2 , have been determined and obtained on BaZr0.1T0.9O3 at 800 o C for 3 hours annealing process and its maximum electric field is noted to be about 38.3 Volt/cm on all samples.In the normal manner,theresultcan provide an explanation of polarization and electrical behavior of ferroelectric sample for further research.

This paper concerns triangular function analysis including triangular function series and triangular function transformation, which is very similar to Fourier analysis based on sine and cosine functions. Besides sine-cosine functions, triangular functions are frequently-used and easily-generated periodic functions in electronics as well, so it is an urgent practical problem to study the basic properties of triangular functions and the fundamental theory of triangular function analysis. We show that triangular functions and sine-cosine functions not only have the similar graphs, but also possess similar analysis properties. Any continuous periodic function may be approximated uniformly by linear combinations of triangular functions as well as trigonometric functions, and every function f(x) ϵ L2[−π,π] has a triangular function series as well as a Fourier series. Since the triangular functions are nonorthogonal in L2[−π,π], the orthonormalization is discussed so that a function f(x) ϵ L2[−π,π] can be approximated best by a superposition of given finite triangular functions. Finally, we introduce the theory of the triangular function transformation in L2(−∞, ∞), which has a close relation with Fourier transformation. These results form the theoretical foundation of the technique of triangular function analysis in modern electronics.

This paper concerns the existence of solutions to the following nonautonomous wave equation gu#uttu ( f 2) f (x, t, !) is nondecreasing in ! and f (x, t, !)=0 if and only if !=0. Our first result deals with the case where f is superlinear at != . Theorem 1. Let ( f 1) and ( f 2) be satisfied. Assume moreover that f satisfies ( f 3) there are r >0 and +>2 such that

Fourier series expansions of different excitation signals for a novel piezoelectric micro-jet is deducted in this paper. By comparison and analysis of the Fourier series expansions, we find that the motivational effect of square wave is preferable than the sine wave which is better than triangle wave. And by analysing the Fourier series expansion of trapezoidal wave, it indicates that the ratio of the waveform parameters to the period should be studied rather than the numerical value of the parameters for improving the injection performance. The numerical simulations and experiments are carried out, and the results are consistent with theoretical calculations.

This work tests the level of security in secure communication systems based on nonlinear dynamics (NLD), or chaos. In these systems, a chaotic carrier signal is used in a type of spread-spectrum signaling system, with the added benefit that the hidden information signal is buried at something of the order of −30 dB with respect to the chaotic carrier. To investigate the level of security in such systems, an examination was conducted on a test set of chaotic carriers and hidden information signals prepared by the NLD research group at the Naval Research Lab. The hidden signals included a triangle wave, a period doubled signal, and a chaotic signal that was different from the chaotic carrier. The analysis process was to use NLD forecasting to predict the carrier dynamics, and then subtract away the predicted values to reveal the hidden signal or at least increase its signal-to-noise ratio with respect to the carrier. In each case, it was a simple task to determine the power spectrum of the hidden signal once the prediction of the carrier was removed. This was then used to create a “comb” filter to extract the correct frequencies from the FFT of the first two signals. When this was done, the hidden signals were recreated with almost perfect accuracy. In the third case, the hidden chaotic signal had a broadband component, so the spectrum was used to develop a Weiner filter which enabled the hidden signal to be reconstructed with only moderate accuracy, where the overall structure of the hidden chaotic signal was preserved, but the fine structure was lost. As a further test, the processing approach was applied to a voice signal hidden in one-dimensional Lorenz data at −35 dB. After subtracting away the carrier model, the voice signal was reconstructed with reasonable accuracy, and had the same characteristic structure. In this case, no secondary filtering was applied. The forecasting approach was then extended to allow for dynamic signal estimation using threshold detection, so that whenever a signal was detected, multiple predictions of the carrier behavior were made into the future. This was tested on a square wave embedded at −42 dB in Lorenz data. The extended approach was able to reveal the square wave with almost perfect precision, except in a few regions where it temporarily lost synchrony with the carrier. This allowed for the elimination of the secondary filtering requirement entirely. The final conclusion is that the secure communications systems based on chaotic carriers may be useful to increase privacy, but are not yet capable of providing a high level of security. The paper concludes with a discussion of measures which may be taken to improve the security of such systems so that they may be applicable to areas where higher security is required.

Steady state visual evoked potential (SSVEP) is the brain's natural electrical potential response for visual stimuli at specific frequencies. Using a visual stimulus flashing at some given frequency will entrain the SSVEP at the same frequency, thereby allowing determination of the subject's visual focus. The faster an SSVEP is identified, the higher information transmission rate the system achieves. Thus, an effective stimulus, defined as one with high success rate of eliciting SSVEP and high signal-noise ratio, is desired. Also, researchers observed that harmonic frequencies often appear in the SSVEP at a reduced magnitude. Are the harmonics in the SSVEP elicited by the fundamental stimulating frequency or by the artifacts of the stimuli? In this paper, we compare the SSVEP responses of three periodic stimuli: square wave (with different duty cycles), triangle wave, and sine wave to find an effective stimulus. We also demonstrate the connection between the strength of the harmonics in SSVEP and the type of stimulus.

Imagery of a general periodic triangular wave object formed by an aberration-free narrow rectangular aperture (slit) with tapered illumination, has been investigated. The system is assumed to be operating in incoherent light. Results have been presented for the far field intensity distribution in the diffraction images and the general triangular wave response of the system. An object function which gives a wave response nearly similar to that of sine wave has been pointed out.

Nonlinear wave equations with explicit periodic plane wave solutions are considered. The variational equations governing linear stability are derived and solved. The analysis is applied to the special cases of λφ4- and Sine-Gordon wave equations.

The capacitance of GaAs/Ge and silicon (BSFR) solar cells are measured at different temperature ranging from 288 to 338 K under dark condition using triangular wave method. It is a frequency domain technique. In the proposed method, the solar cells are biased externally using DC voltage at the desired operating voltage and the AC triangle wave small signal of desired amplitude with variable frequencies are applied. The resultant AC current of the device is measured and the cell capacitance is calculated. GaAs/Ge solar cell has shown only transition capacitance throughout its operating voltage while silicon (BSFR) solar cell exhibited both transition and diffusion capacitances. It is a direct and simple measurement technique in comparison to impedance spectroscopy and other bridge methods.

In a self-mixing type laser range finder the current of the laser is modulated with a triangle wave to produce a range of optical frequencies. However, the electrical signal does not produce a perfect linear sweep in optical frequency due to thermal and other effects in the laser. This leads to errors in the accuracy and resolution of the range finder. In this paper, we describe and implement a method in software to systematically determine the optimal shape of the injected waveform needed to eliminate these thermally induced measurement errors. With this method we do not require the more complicated and expensive optical techniques used by other researchers to recover the optical frequency variations with regard to injection current. The averaging of a reasonable number of samples gave sub-millimeter accuracy when the optimal current shape was used. The uncertainty in the average measurements are improved by roughly six times compared to the conventional triangular modulation. The reshaping also results in the range finding system being less sensitive to changes in ambient temperature.

At the APS Retreat in May 2002, G. Rosenbaum proposed a method for increasing the effective vertical emittance of the APS beam. His proposal, illustrated in Figure 1, is to use a rapidly-modulated four-magnet vertical position bump in a single straight section. The proposed modulation frequency is a 10-kHz triangle wave, with a kick angle of 0.65 mrad. There are several aspects of this proposal that may be problematical: (1) The high modulation frequency will require the use of a ceramic chamber with a thin conductive coating, similar to what is used for the injection kicker magnets. This is not necessarily a problem, but the following aspects need to be examined: (a) The chamber coating needs to be specified correctly to ensure that the beam motion reflects the desired triangle-wave pattern. (b) The effect of the eddy currents in the chamber on the multipole content of the magnetic field needs to be computed, to ensure that the system does not have undesirable effects on the beam. (2) The magnets and their chambers will require careful matching in order to ensure that the beam is not disturbed outside of the bump. We know from experience with the APS kickers that this can be difficult. These issues are examined in the remainder of this note. The magnet and power supply designs are beyond our scope. We simply point out that these will not be conventional magnets or power supplies. The magnets will almost certainly need to be of ferrite construction, similar to the injection kickers. The power supplies will be unique and unlike anything else in the APS ring.

Breakthrough times of a commercially-available respirator cartridge packed with a small amount of activated carbon were determined by three different flow patterns: workers' respiratory patterns, conventional steady-state flows, and three standard patterns consisting of rectangle, sine, and triangle waves. A mechanical breathing simulator was used to reproduce the three standard wave patterns as well as the workers' respiratory patterns, which had been recorded from three workers of a paint manufacturing plant wearing a gas mask equipped with a respirator cartridge. The breakthrough test was carried out with 300 ppm carbon tetrachloride vapor at average flow rates of the respiratory and standard patterns equivalent to the steady-state flow rates. The breakthrough times determined by the workers' respiratory patterns were found to be shorter than those by a steady-state flow of the equivalent flow rate, and to be as short as those by sine and triangle wave patterns. It was considered that shorter breakthrough times in the workers' respiratory patterns could be attributed to a faster maximum inspiratory flow rate than that in the case of steady-state flow. The present results suggest that the passing time of CCl4 molecules through the thin activated carbon layer of respirator cartridge may be too short to attain an adsorption equilibrium.

The Poisson problem with homogeneous Dirichlet boundary conditions is considered on a triangle. The transformation from square to triangle is realized by mapping an edge of the square onto a corner of the triangle. Then standard Chebyshev collocation techniques can be implemented. Numerical experiments demonstrate the expected high spectral accuracy for smooth solutions. Furthermore, it is shown that finite difference preconditioning can be successfully employed to construct an efficient iterative solver. Then the convection–diffusion equation is considered. Here finite difference preconditioning with central differences leads to instability. However, using the first-order upstream scheme, we obtain a stable method. Finally, a domain decomposition technique is applied to the patching of rectangular and triangular elements.

Four-switch three-phase inverters (FSTPIs) have been proposed to be used in low-cost applications because of the reduced number of semiconductor devices, and space vector pulse width modulation (SVPWM) techniques have also been introduced to control FSTPIs. However, high-performance controllers are needed to implement complicated SVPWM algorithms, which limits their low-cost applications. To simplify algorithms and reduce the cost of implementation, an equivalent scalar method for SVPWM of FSTPIs is proposed. SVPWM for FSTPIs is actually a sine PWM by modulating two sine waves of 60° phase difference with a triangle wave, so such a special sine PWM can be used to control FSTPIs. The simulation and experimental results demonstrate the validity of the proposed method.

In an effort to increase camera readout speed, we have developed a nonconventional vidicon tube scanning technique. Because all vidicon targets are round, acquiring a full view requires overscanning with a conventional square format scan, resulting in 22% of the video field time wasted. Furthermore, conventional scanning employs horizontal flyback, which for high frame rates can be more than 10% of the total field time. Our nonconventional scanning technique eliminates flyback time by utilizing a triangular waveform rather than a sawtooth for horizontal deflection. This triangle wave is amplitude modulated in order to scan only the (circular) area of interest. The vertical deflection is a staircase ramp, with a step occurring at the end of each horizontal line. This maintains even spacing and a parallel relationship between horizontal lines, as opposed to skewed lines with conventional scans. To display the video output, the X-Y monitor must also be driven with these waveforms in order to maintain the correct temporal and spatial position of the video data. Sweep rates of 400 lines in a 1 ms field have been demonstrated. Test results using this technique show a frame time reduction of approximately 30%, with no loss of resolution or dynamic range, and no increased video bandwidth requirements.© (1992) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Piezoelectric tube scanners are the actuators of choice in scanning probe microscopy. These nanopositioners exhibit a dominant first resonant mode that is excited due to harmonics of the input scan signal. This introduces errors in the scan obtained. The presence of this resonant mode limits the upper bound of a triangular scan rate to around 1/100th of the first mechanical resonance frequency. Passive and active shunts have shown to damp this resonant mode substan- tially and improve scan performance. Sensorless active shunts optimised using H2 and H1 tech- niques, is designed. These shunts reduce the amplitude of the first resonant peak of a prototype tube nanopositioner by 24 dB. A triangle wave input is used to test the improvement in scan per- formance due to the damping achieved by these active shunts. Analysis shows that damping the resonant mode in such fashion reduces the scan error by five times.

The paper describes two programs of a suite which is under development which enables the student to explore the behaviour of controlled and autonomous linear discrete time systems without the necessity to learn a simulation language. The first program, DCSS (Digital Control System Simulator), deals with the simulated behaviour of discrete systems with or without a variety of controllers. A wide range of default systems, up to fifth order with time delay, can be selected by single keystrokes; the range of inputs includes square wave, triangle wave, sinusoidal and repeated pulse signals and noise or constant offsets can be added. The second program, Filter, provides the user with a powerful digital filter design and simulation facility. Again, all options can be achieved with one or more keystrokes to select options from a menu. On starting the program, the user selects IIR or FIR filter structures, sets the clock rate and can then choose to design a filter, see the time response or see the frequency response. Consider, for the sake of brevity, the case of an MR filter. In the design sub-section, the user can specify the filter order, select Butterworth, Bessel, Chebyshev, Elliptic, Bessel or RC filters and lowpass, highpass, bandpass or bandstop characteristics. The programs are fully interactive and the user can interupt the program to alter the system, controller, set point or feedback configuration by single keystrokes.

A repeated scanning algorithm for determining the minimax approximation to an arbitrary function by means of a piecewise linear function with a fixed number of variable knots is described, and it is compared to optimal and suboptimal methods.