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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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Book ChapterDOI
01 Jan 2009
TL;DR: Fourier transform infrared (FTIR) spectroscopy is one of the most powerful techniques for chemical analysis in recent years, and is making new inroads into several applications in biological analysis, including food as mentioned in this paper.
Abstract: Fourier transform infrared (FTIR) spectroscopy is considered to be one of the most powerful techniques for chemical analysis in recent years, and is making new inroads into several applications in biological analysis, including food. Fourier transformation (FT) is a mathematical procedure that is applied to the interferograms to obtain the spectrum. Essentially, FT breaks down the interferogram provided by the interferometer into sine waves for each wavelength in the light. These sine waves are arranged over the wavelength to produce the conventional spectrum. Many different types of materials and components are available for FTIR construction. The important components of an FTIR spectrometer are the interferometer, source, beam splitter, detector, and laser. One of the most important components of interferometer is the moving mirror that is required to control its position precisely in order to obtain an accurate measurement of spectra. The function of the detector is to transduce the light intensity received by it to electrical signal. Two most commonly used detectors in both FT-near-infrared (FT-NIR) and FT-mid-infrared (FT-MIR) instruments are the deuterated triglycine sulfate (DTGS), detectors and the mercury cadmium telluride (MCT) detectors.

53 citations

Patent
29 Nov 1985
TL;DR: In this paper, a sinusoidally weighted pulse width modulated signal is used to switch a pair of solid state power switches on and off in alternation in order to connect the motor alternately across positive and negative power supplies.
Abstract: A substantially perfect single phase sinusoidal shaped voltage waveform may be generated for driving a single phase a-c induction motor by employing a sinusoidally weighted pulse width modulated signal to switch a pair of solid state power switches on and off in alternation in order to connect the motor alternately across positive and negative power supplies. A low pass filter is effectively connected in series with the single phase motor to filter out all of the signal components except the fundamental of the sine wave modulating frequency. In this way, only a sinusoidal voltage is applied to the motor. By making the switching frequency very high relative to the sine wave modulation component, the filter size and cost are minimized and it is unnecessary to correlate or synchronize the sine wave modulation and switching frequencies.

53 citations

Patent
07 Jun 1996
TL;DR: In this article, a sensor signal is extracted and demodulated from a signal flowing in a motor by a band pass filter, and this is defined as a rotation position detection signal.
Abstract: The present invention provides a rotation position detecting circuit for a sensor-less motor, and a motor device, which do not use a back electro-motive voltage. A motor (1) is rotated and driven by adding a sensor signal having a high frequency to a sine wave drive signal and a cosine wave drive signal through adders (5S) and (5C), respectively. A sensor signal is extracted and demodulated from a signal flowing in the motor (1) by a band pass filter (9), and this is defined as a rotation position detection signal. In the sensor signal from the band pass filter (9), its current value is changed corresponding to a change of an impedance resulting from a rotation of a magnet of the motor. It is possible to detect the rotation position of a rotor magnet, by detecting the change of the current value.

53 citations

Journal ArticleDOI
TL;DR: The changes in the tuning properties due to noise found here, as well as preliminary psychophysics data, imply that external noise is relevant for sensing small periodic signals in the environment.
Abstract: Fibers from the tibial nerve of rat were isolated and spike activity recorded using monopolar hook electrodes. The receptive field (RF) of each recorded unit on the glabrous skin of the foot was mechanically stimulated with waveforms comprised of various frequency sine waves in addition to increasing levels of white noise. Single-unit responses were recorded for both rapidly adapting (RA) and slowly adapting (SA) units. Signal-to-noise ratio (SNR) of the output was quantified by the correlation coefficient (C1) between the input sine wave and the nerve responses. The addition of noise enhanced signal transmission in both RA and SA fibers. With increasing noise, the initially inverted "V"-shaped, zero-noise tuning curves for RA fibers broadened and eventually inverted. There was a large expansion of the frequencies that the RA receptor responded to with increasing noise input. On the other hand, the typical shape of the SA fiber tuning curves remained invariant, at all noise levels tested. C1 values continued to increase with larger noise input for higher frequencies, but did not do so at the lowest frequencies. For both RA and SA fibers the responses with added noise tended to be rate modulated at the low-frequency end, and followed nonlinear stochastic resonance (SR) properties at the higher frequencies. The changes in the tuning properties due to noise found here, as well as preliminary psychophysics data, imply that external noise is relevant for sensing small periodic signals in the environment. All current models of sensory perception assume that the tuning properties of receptors determined in the absence of noise are preserved during everyday tasks. Our results indicate that this is not true in a noisy environment.

53 citations

Journal ArticleDOI
TL;DR: In this paper, the influence of the solar radiation variation on the performances of a stand-alone photovoltaic pumping system is analyzed, and it is shown that the decrease of solar radiation degrades performances (global efficiency and flow rate) of the PV pumping system.

53 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202378
2022157
2021138
2020253
2019344
2018336