Topic
Sine wave
About: Sine wave is a research topic. Over the lifetime, 12183 publications have been published within this topic receiving 93013 citations. The topic is also known as: sinusoid.
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TL;DR: An accurate, uniform asymptotic approximation describing the dynamical evolution of the unit step-function modulated sine wave signal through a single-resonance Lorentz model dielectric is presented here based upon their work.
Abstract: A canonical problem of central importance in the theory of ultrawideband pulse propagation through temporally dispersive, absorptive materials is the propagation of a Heaviside step-function signal through a medium that exhibits anomalous dispersion. This problem is rich in the use of asymptotic theory. Sommerfeld and Brillouin provided the first (qualitatively accurate but quantitatively inaccurate) closed-form approximations of the dynamic evolution of this waveform through a single-resonance Lorentz model dielectric based upon Debye's method of steepest descent. An improved approximation has since been provided by Oughstun and Sherman using modern, uniform asymptotic methods that rely upon the saddle-point method. An accurate, uniform asymptotic approximation describing the dynamical evolution of the unit step-function modulated sine wave signal through a single-resonance Lorentz model dielectric is presented here based upon their work. This refined asymptotic description results in a continuous evolution of the propagated field for all space-time points.
33 citations
Patent•
03 Mar 1999TL;DR: In this paper, a rotating machine with employment of a sensorless DC brushless motor is corrected in a phase corrector by using a motor phase current signal, which is processed in an integrator and a comparator so as to be converted into an ON/OFF signal having a duty ratio of 1:1.
Abstract: In a rotating machine with employment of a sensor-less DC brushless motor, a terminal voltage of a motor is corrected in a phase corrector by using a motor phase current signal. At this time, the terminal voltage is processed in an integrator and a comparator so as to be converted into an ON/OFF signal having a duty ratio of 1:1. Then, a rotation signal is produced based on an induced voltage which is generated by rotating a permanent magnet rotor, so that a rotation sensor is no longer required. On the other hand, an output derived from the phase corrector is entered as a 1-pulse/1-rotation output signal into a PLL circuit. The PLL circuit contains a phase comparator, a low-pass filter, an oscillator, and a counter. The PLL circuit frequency-divides the 1-pulse/1-rotation output signal. The sine wave data are stored into a ROM with respect to each of the frequency-divided signal positions. The unbalance vibrations of the magnetic bearing are controlled every frequency-divided signal.
33 citations
TL;DR: In this article, an accurate ac and dc bipolar voltage source based on quantized pulses of Josephson junctions was developed. But the performance of the source was limited to a factor of 6 increase in output voltage over previous unipolar waveforms.
Abstract: We have developed an accurate ac and dc bipolar voltage source based on the quantized pulses of Josephson junctions. A factor-of-6 increase in output voltage over previous unipolar waveforms is achieved by generating bipolar waveforms where arrays of junctions are biased with both a broadband two-level digital code and a sine wave. We use simulations to determine the optimum operating conditions as a function of frequency and as a function of the phase difference between the digital code and the sinusoidal drive.
33 citations
TL;DR: The results show that the accelerometer measurements matched the theoretical amplitude to within 1-3% over most of the range but showed significant offset drift, and the acceleration estimates based on the position measurements were highly dependent on the filtering scheme, showed no significant offset but had higher levels of noise.
33 citations
TL;DR: The effective resolution of AD converters is a crucial quantization quality parameter in modern instrumentation and the expected values and variances are derived and analyzed versus the offset and the number of quantizing levels.
Abstract: The effective resolution of AD converters is a crucial quantization quality parameter in modern instrumentation. A usual theoretical assumption about the quantized (training) signal is that it is a pure sine wave with a "zero" offset. This means that either the average value of the sine wave is equal to one of the threshold levels (quantizer without dead zone) or that it lies exactly in the middle of them (rounding quantizer). In the measurement technique this assumption is hardly fulfilled, and that is why we meet something intermediate between the above-mentioned hypothetical situations. Here we generalize the known results for "zero" offset to the case of unknown offset. A general problem of an arbitrary random offset distribution is considered first. Two important practical cases are then analyzed. The first one is an unknown and nonrandom offset (one-point distribution). The second one is a case of a uniform distribution of the offset (effect of dithering on quantizer input). In particular, the expected values and variances are derived and analyzed versus the offset and the number of quantizing levels. The results obtained are applied to the effective resolution measurement.
33 citations