Showing papers on "Sine wave published in 2002"

Control Theory for Humans: Quantitative Approaches To Modeling Performance

Abstract: Contents: Preface. Perception/Action: A Systems Approach. Closing the Loop. Information Theory and Fitts' Law. The Step Response: First-Order Lag. Linear Systems: Block Diagrams and Laplace Transforms. The Step Response: Second-Order System. Nonproportional Control. Interactions Between Information and Dynamic Constraints. Order of Control. Tracking. There Must Be 50 Ways to See a Sine Wave. A Qualitative Look at Fourier Analysis. The Frequency Domain: Bode Analysis. The Frequency Domain: Describing the Human Operator. Additional Adaptive Aspects of the Crossover Model. Driving Around in Circles. Continuous Tracking: Optimal Control. Estimating and Predicting the State of a Dynamic System With Lag-Like Calculations. Varieties of Variability. Lifting a Glass of Juice. Sine Wave Tracking Is Predictably Attractive. Going With the Flow: An Optical Basis for the Control of Locomotion. Fuzzy Approaches to Vehicular Control. Learning to Control Difficult Systems: Neural Nets. Some Parallels Between Decision Making and Manual Control. Designing Experiments With Control Theory in Mind. Adaptation and Design. Appendix: Interactive Demonstrations.

Monocycle shapes for ultra wideband system

Abstract: Ultra wideband (UWB) is a promising technique for wireless communications. It is a carrier-free (base-band) technique, which can greatly reduce the complexity and cost of the transceiver. In contrast with conventional communication systems using the "sine wave", UWB information is carried in a very short pulse, which covers an extremely wide spectrum bandwidth. Several candidate monocycle (narrow pulse) shapes are investigated, their spectrum characteristics and BER performance in AWGN using pulse position modulation (PPM) are simulated, and the results are compared. Their performances in the fading multipath channel are also investigated.

Biosensor apparatus and method with sample type and volume detection

Abstract: A biosensor apparatus and method with sample type and cell volume detection. The apparatus includes a sine wave generator to apply an AC signal to a biosensor cell containing a sample, a current-to-voltage converter, a phase shifter, a square wave generator, a synchronous demodulator, and a low pass filter which yields a signal proportional to the effective capacitance across the biosensor cell, which is proportional to the volume of the sample. In addition, the current-to-voltage converter yields a signal indicative of the type of sample contained within the biosensor cell. The method includes applying a sine wave to the biosensor cell, shifting the phase of the resultant signal, generating a square wave synchronous with the sine wave, demodulating the resultant signal with the square wave, and filtering the demodulated signal to produce a signal proportional to the effective capacitance across the biosensor cell. The biosensor apparatus and method are capable of determining sample type and measuring glucose levels over a wide range of sample volumes.

Method and apparatus for processing a physiological signal

Abstract: A signal processing method, preferably for extracting a fundamental period from a noisy, low-frequency signal, is disclosed. The signal processing method generally comprises calculating a numerical transform for a number of selected periods by multiplying signal data by discrete points of a sine and a cosine wave of varying period and summing the results. The period of the sine and cosine waves are preferably selected to have a period substantially equivalent to the period of interest when performing the transform.

Synthesis of precision AC waveforms using a SINIS Josephson junction array

Abstract: A synthesizer of precision ac waveforms based on a binary superconductor insulator-normal metal-insulator-superconductor (SINIS) Josephson junction array has been developed. The array segments are individually biased using a high-speed bias source which gives a switching time of approximately 250 ns between voltage steps. The accuracy limitations of the system due to limited risetime and bandwidth are discussed. Comparisons between the synthesizer and a planar multijunction thermal converter (PMJTC) indicate that it is possible to synthesize sine waves with known rms value having an accuracy in the range of 1 part in 10/sup 7/.

Laser spectral engineering for lithographic process

Abstract: An integrated circuit lithography technique called spectral engineering by Applicants, for bandwidth control of an electric discharge laser. In a preferred process, a computer model is used to model lithographic parameters to determine a desired laser spectrum needed to produce a desired lithographic result. A fast responding tuning mechanism is then used to adjust center wavelength of laser pulses in a burst of pulses to achieve an integrated spectrum for the burst of pulses approximating the desired laser spectrum. The laser beam bandwidth is controlled to produce an effective beam spectrum having at least two spectral peaks in order to produce improved pattern resolution in photo resist film. Line narrowing equipment is provided having at least one piezoelectric drive and a fast bandwidth detection control system having a time response of less than about 2.0 millisecond. In a preferred embodiment, a wavelength tuning mirror is dithered at dither rates of more than 500 dithers per second in phase with the repetition rate of the laser. In one case, the piezoelectric drive was driven with a square wave signal and in a second case it was driven with a sine wave signal. In another embodiment, the maximum displacement was matched on a one-to-one basis with the laser pulses in order to produce a desired average spectrum with two peaks for a series of laser pulses. Other preferred embodiments utilize three separate wavelength tuning positions producing a spectrum with three separate peaks.

Optical single sideband transmitter

Abstract: With the normal modulation method, it is difficult to construct a Hilbert transform device because it is complicated. To solve the problem, the present invention generates a single sideband modulated optical pulse train by driving a Mach-Zehnder optical modulator for optical pulse generation with a laser source's sine wave clock signals rendered 90 degrees out of phase from each other. The generated pulse train is entered into an optical modulator, modulated with an NRZ (nonreturn-to-zero) data signal, and filtered by a narrow-band optical filter to obtain one of two sidebands.

High-frequency DC link inverter for grid-connected photovoltaic system

Abstract: This paper proposes an inverter for the grid-connected photovoltaic system based on the transformerless inverter. This system consists of a high frequency inverter bridge, high frequency transformer, diode bridge rectifiers, a DC filter, a low frequency inverter bridge, and an AD filter. The high frequency inverter bridge switching at 20 kHz is used to generate bipolar PWM pulse, which is subsequently rectified by diode bridge rectifiers to result in a full-wave rectified sine wave. Finally, it is unfolded by a low frequency inverter bridge to result in a 60 Hz sine wave power output. In this paper, the control algorithm for synchronous current feedback control method and a maximum power point tracking (MPPT) method using DSP are described. The simulation and experimental results are shown to verify the validity of the proposed system.

Experimental investigation of active vibration control using neural networks and piezoelectric actuators

Abstract: The use of neural networks for identification and control of smart structures is investigated experimentally. Piezoelectric actuators are employed to suppress the vibrations of a cantilevered plate subject to impulse, sine wave and band-limited white noise disturbances. The neural networks used are multilayer perceptrons trained with error backpropagation. Validation studies show that the identifier predicts the system dynamics accurately. The controller is trained adaptively with the help of the neural identifier. Experimental results demonstrate excellent closed-loop performance and robustness of the neurocontroller.

Simulated wave massage

Abstract: Method, procedure, and device for applying tactile sensation and vibration to the human body. In this invention one (or more vibrating) elements emit sine waves between 20 and 800 Hz. These waves are varied in frequency, amplitude and rhythm to create in the subject the sensation of massage moving through different parts of the body even though the signal emitter may be a point source.

Audio Signal Processing Based on Sinusoidal Analysis/Synthesis

Abstract: Based on a sinusoidal model, an analysis/synthesis technique is developed that characterizes audio signals, such as speech and music, in terms of the amplitudes, frequencies, and phases of the component sine waves. These parameters are estimated by applying a peak-picking algorithm to the short-time Fourier transform of the input waveform. Rapid changes in the highly resolved spectral components are tracked by using a frequency-matching algorithm and the concept of“birth”and“death”of the underlying sine waves. For a given frequency track, a cubic phase function is applied to the sine-wave generator, whose output is amplitude-modulated and added to sines for other frequency tracks. The resulting synthesized signal preserves the general wave form shape and is nearly perceptually indistinguishable from the original, thus providing the basis for a variety of applications including signal modification, sound splicing, morphing and extrapolation, and estimation of sound characteristics such as vibrato. Although this sine-wave analysis/synthesis is applicable to arbitrary signals, tailoring the system to a specific sound class can improve performance. A source/filter phase model is introduced within the sine-wave representation to improve signal modification, as in time-scale and pitch change and dynamic range compression, by attaining phase coherence where sinewave phase relations are preserved or controlled. A similar method of achieving phase coherence is also applied in revisiting the classical phase vocoder to improve modification of certain signal classes. A second refinement of the sine-wave analysis/synthesis invokes an additive deterministic/stochastic representation of sounds consisting of simultaneous harmonic and aharmonic contributions. A method of frequency tracking is given for the separation of these components, and is used in a number of applications. The sine-wave model is also extended to two additively combined signals for the separation of simultaneous talkers or music duets. Finally, the use of sine-wave analysis/synthesis in providing insight for FM synthesis is described, and remaining challenges, such as an improved sine-wave representation of rapid attacks and other transient events, are presented.

High torque brushless DC motors and generators

Abstract: This invention relates to geometric, electrical, and electronic techniques improving torque, power, cost, size, weight, reliability, and efficiency of electric generators and motors using the following: Geometric relationships eliminating lateral magnetic short circuits, providing sine wave output waveforms, and allowing axial extendibility; Radial and axial Permanent Magnet concentration; Speed independent rotating transformer inductive coupling; Precise speed independent rotor position sensing using a threshold and comparator circuit to provide Hall Effect low speed & Back-EMF medium to high speed sensing; Bi-directional Buck-Boost PWM converter topology using H-bridge power transistors, parallel reverse diodes and an H-bridge connected inductor.

Fractional-N frequency synthesizer with sine wave generator

Abstract: A fractional-N frequency synthesizer is disclosed wherein the multi-modulus frequency divider in the feedback path of the phase locked loop is controlled by a delta-sigma modulator to achieve the desired division ratio. The fractional input control signal to the delta sigma modulator is dithered to break any periodicity in the modulator output signal to avoid the generation of fractional spurious frequencies.

Inverter for producing a true sine wave

Abstract: A power inverter includes a transformer (2) having a primary winding (4) with a first (5) and second ends (6) and a tap (3) between the first (4) and second ends (4) for receiving a DC voltage input (1), and a secondary winding (8) for outputting an output waveform. A comparator (16) compares the output waveform to a reference signal (20) and outputs a correction signal based on the comparison. A controller (14) receives the correction signal and provide a switching signal. The duty cycle of the switching signal is adjusted based on the correction signal. First (10) and second (12) switches are coupled to the first (5) and second ends (6), respectively, of the primary winding (4). The first (5) and second switches (6) switch the transformer (2) in accordance with the switching signal so that the output waveform tracks the reference signal (20).

Analog quadrature modulator (AQM) error compensating apparatus and method

Abstract: An AQM error compensating apparatus includes: a predistorter for distorting a signal so as to have the opposite characteristics of nonlinear distortion characteristics of a digital input signal; an error compensating unit for compensating I/Q digital signals outputted from the predistorter according to an error correction signal; a digital/analog converter for converting the I/Q digital signals of the error compensating unit into I/Q analog signals; a modulator for frequency-modulating the I/Q analog signals outputted from the digital/analog converter; a power amplifier for amplifying the output signal of the modulator to a directional coupler; a down-converter for down-converting a feedback signal inputted from the directional coupler; an analog/digital converter for converting the output signal of the down-converter into a digital signal; and a controller for comparing the output signal of the analog/digital converter with the I/Q digital signals inputted from the predistorter, and applying an extracted error correction signal into the error compensating unit. An AQM error can be compensated by extracting the DC offset and gain and the correction value for the phase error by using a sine wave for an initial certain time of a system, and even while a signal is being transmitted after being varied, the AQM error also can be compensated by comparing an inputted reference signal and a feedback signal and extracting a correction value for each error. Thus, the error can be accurately compensated according to its occurrence.

Calibration method for interleaving an A/D converter

Abstract: A method and low cost apparatus to accurately determine the gain, offset, and/or skew calibration values of each A/D converter in a few steps for an interleaving A/D converter. The calibration method includes: applying sine waves to the input as a calibration signal during calibration, A/D converting of the sine wave by a plurality of A/D conversion means in a predetermined order and storing the converted data in a data storage memory, and determining the gain, offset, and/or skew calibration values by using sine curve fitting on a sequence of converted data for each of the plurality of A/D conversion means.

Grid-connected inverter arrangement

Abstract: PROBLEM TO BE SOLVED: To provide a low-cost grid-connected inverter arrangement capable of stopping a grid-connected operation by detecting an abnormality of a parallel-off switch before the grid-connected operation is started. SOLUTION: A grid-connected inverter arrangement 2 comprises an inverter circuit 3 composed of a step-up circuit 4 for stepping up the output of a solar cell 1, a sine wave generating circuit 5 for converting the output of the step-up circuit 4 to an AC voltage, and a filter circuit 6 that smoothes the output of the sine wave generating circuit 5; a parallel-off switch 7 connected between the inverter circuit 3 and a commercial grid 30, a control circuit 8 to control the output of the inverter circuit 3; and a voltage detector 9 for detecting an inter-terminal voltage on the inverter circuit 3 side of the parallel-off switch 7. The control circuit 8 stops an inverter operation and determines whether the parallel-off switch 7 is normal or not based on the inter-terminal voltage detected by the voltage detector 9 immediately before the starting of the grid-connected operation in which the parallel-off switch 7 is turned off. If it is decided to be abnormal, the grid-connected operation is suspended. COPYRIGHT: (C)2004,JPO&NCIPI

Single-phase integrated power quality compensator based on capacitor-clamped configuration

Abstract: A control scheme of an integrated power quality compensator, which employs an active rectifier to work simultaneously as an active power filter (APF) to decrease current harmonics, is proposed. The employed rectifier is based on a capacitor-clamped configuration to produce multilevel pulsewidth modulation waveforms which result in low voltage stress and low conduction loss on the power switches. The proposed active rectifier is controlled to track the supply current to be a sinusoidal wave with low current harmonics. The advantages of the proposed control scheme are high power factor, low current harmonics, no complicated calculations for current harmonics elimination, and no dedicated APF needed for harmonic elimination. The experimental results are used to verify the validity and effectiveness of the proposed control scheme.

Microwave hologram reconstruction for the RASCAN-type subsurface radar

Abstract: In this paper the mathematical models and results on processing the experimental single-frequency microwave holograms received by scanning subsurface radar with sine wave signal are submitted. The holograms reconstruction method with the use of support functions, which take into account the near field of the aperture antenna with round cylindrical waveguide, is analysed. The models consider both known and unknown phase shift of the signal reflected from the point object. It is theoretically and experimentally shown that single- frequency holograms reconstruction allows to estimate depth of shallowly buried objects and improve the resolution on the probing surface with the growth of objects depths.

Dynamic testing of shock absorbers under non-sinusoidal conditions

Abstract: This paper deals with the dynamic characterization of an automotive shock absorber, the continuation of an earlier work ( 1). The objective of this ongoing research is to develop a testing and analysis methodology for obtaining dynamic properties of automotive shock absorbers for use in CAE-NVH low-to-mid-frequency chassis models. Stepped sine sweep excitation is currently used in industry to obtain shock absorber parameters along with their frequency and amplitude depen- dence. Sine-on-sine testing, which involves excitation using two di Verent sine waves, has been done in this study to understand the e Vects of the presence of multiple sine waves on the estimated dynamic properties. In an e Vort to obtain all frequency dependent parameters simultaneously, di Verent types of broadband random excitation have also been studied. Results are compared with stepped sine sweep tests. Additionally, actual road data measured on di Verent road proe les have been used as input excitation to obtain the shock absorber parameters for broad frequency bands under realistic amplitude and frequency conditions. These results are compared with both simulated random excitation and stepped sine sweep test results.

Single bubble sonoluminescence driven by non-simple-harmonic ultrasounds.

Abstract: The dependence of the single bubble sonoluminescence (SBSL) on the waveforms of the driving ultrasound has been investigated by both experiment and numerical calculation. Three types of non-simple-harmonic waves, the rectangular, triangular and as well as the sinusoidal wave with a pulse, are used to drive the SBSL in our research. The triangular wave is the most effective, while the rectangular wave is the worst and the sinusoidal wave in the middle. However, the rectangular wave drives the brightest SBSL among those waves if the sound pressure amplitude keeps constant. When we use a simple-harmonic wave with a pulse as the driving sound, stable and periodic SBSL flashes have been observed. An increase in the flash intensity can be observed as the pulse is put at a suitable phase related to the sinusoidal wave. All of the observations are investigated numerically. Well qualitative agreements between the numerical simulations and the experimental measurements have been achieved.

Improvement of IPMSM sensorless control performance by suppression of harmonics on the vector control using Fourier transform and repetitive control

Abstract: In the case of the sensorless control for the PMSM that estimates position and velocity from EMF using the model of a synchronous motor with the voltage and current, it is desirable for the voltage and current to be perfect sine waves However, in fact, various harmonic components are contained in the voltage and current, and they have bad influence on the estimation performance of a sensorless control In this paper, we propose an improving method of sensorless control performance for the IPMSM by suppression of harmonic component in the current control loop of the vector control using Fourier transform and repetitive control To suppress harmonic components, compensation signals are acquired using Fourier transform and repetitive control, and feedforward control is implemented with acquired compensation signals To evaluate our proposed system, the sensorless control system for the IPMSM is taken for instance The system is constructed on the basis of the extended EMF disturbance observer with the current and voltage command whose harmonic components are suppressed As a result, we can have a margin in pole assignment of the disturbance observer, and the performance of sensorless control can be improved The effectiveness of the proposed method is confirmed by experimental results

Dual sided self-oscillation circuit for driving an oscillatory actuator

Abstract: A dual sided self-oscillation circuit for driving an oscillatory actuator with high efficiency and high response speed. The actuator has a winding to receive a periodical supply current from a power source and oscillates in a predetermined resonant frequency. The self-oscillation circuit includes a bandpass filter for receiving a back electromotive force voltage (Vbemf) developed across the winding and producing a sine wave output signal, a comparator for comparing the sine wave output signal with a threshold voltage and producing two drive pulses per cycle of the resonant frequency, and a switch connected in series with the winding to connect or disconnect the power source to the winding in response to the drive pulses, thereby flowing electric current in two directions at each cycle.

Method and apparatus to compensate for cyclic load disturbances in a control system

Abstract: A method and apparatus for essentially eliminating cyclic disturbances in a motor control system, the method including identifying frequencies of undesirable components in a feedback signal that exceed a threshold level and generating a combined signal including sine wave components corresponding to each of the identified frequencies, delaying the combined signal to generate a plurality of identical but phase shifted combined signals, weighting each one of the delayed signals as a function of the magnitude of an instantaneous corrected signal which is the difference between a velocity error signal and a compensation signal and adding each of the weighted signals to generate the compensation signal.

Neural-network-based adaptive predictive control for vibration suppression of smart structures

Abstract: A neural-network-based adaptive predictive controller is developed and validated experimentally. On-line nonlinear plant identification is performed using a multilayer perceptron neural network with tapped delay inputs. The performance index includes the squared value of plant response (which is desired to be zero for vibration suppression) and a weighted squared change in the control signal. The one-step ahead prediction of plant response is used to minimize the performance index. Efficient algorithms are used for on-line plant identification and performance index minimization to achieve real-time control of plant with relatively fast response time. Piezoelectric actuators are employed to reduce the vibrations with sine wave and band-limited white noise excitation. Experimental results demonstrate the excellent performance of the developed control system. Adaptive control is verified through similar performances with changes in the plant dynamics and external excitation.

An analogue switch using a current conveyor

Abstract: An analogue switch using a current conveyor CCII–7 is presented. The proposed switch can simulate a true switch with transfer of both voltage and current. A theory of operation is described. The proposed switch is verified by using the PSPICE program with a 0.5 μm MOSFET model from MIETEC. Simulation results show that the proposed switch yields an operational range between −300 mV and 300 mV with a supply voltage of ±1.2 V and a load resistor of 100 kΩ. An error in this range is lower than 2%. Switching of a 1 MHz sine wave is also shown.

Sine wave variable speed drive

Abstract: The present technique utilizes already existing components within a variable speed drive to provide harmonic filtering characteristics. Particularly, the present technique integrates transformers and inductors to provide a filter within the variable speed drive. Further, the present technique may also utilize a sine wave filter to provide additional filtering of unwanted frequencies.

A new quasi-resonant inverter with two-way short-circuit switch across a resonant capacitor

Abstract: Two frequencies are often used in induction heating, that is, a lower frequency f/sub L/ is for preheating and a higher frequency f/sub H/ is for main heating in order to decrease thermal stress. In this case, each of f/sub H/ and f/sub L/ is generated by the different inverter, and f/sub H/ approximately equals several times to ten times of f/sub L/. The authors propose a new quasi-resonant inverter that has a two-way short-circuit switch across the resonant capacitor. The proposed inverter has features that its operating frequency is adjustable and the frequency range is so wide that the higher frequency can be ten times as much as the lower frequency. It is considered that the output current has only a fundamental wave by properly manipulating the shorting time of the resonant capacitor even though the output current is not a sinusoidal wave.