نتایج جستجو برای: harmonics
تعداد نتایج: 9680 فیلتر نتایج به سال:
In this paper, the Koch fractal shape is applied for the first time to microstrip bandpass filters integrated on a high-resistivity Si substrate. By using this method, the second harmonics of the filter can be suppressed to about -40 dB. Conventional microstrip coupled line filters are popular in RF front ends, because they can be easily fabricated and integrated with other RF components. Howev...
The Linac Coherent Light Source (LCLS) started user commissioning in October of 2009, producing Free Electron Laser (FEL) radiation between 800 eV and 8 keV [1]. The fundamental wavelength of the FEL dominates radiation in the beamlines, but the beam also produces nonnegligible levels of radiation at higher harmonics. The harmonics may be desirable as a source of harder X-rays, but may also con...
On the basis of simple heuristic models, we show that atomic electrons can (1) amplify fields observed at the nucleus, (2) generate harmonics, and (3) drive higher multipolarities. We consider a model with the nucleus at the focus of a uniformly charged ellipsoid. It amplifies an oscillating external electric field and produces an oscillating electricfield gradient but no higher derivatives. Th...
A novel Short Time Fourier Transform (STFT) based speech enhancement method is introduced. This method enhances the magnitude spectrum of a noisy speech segment. The new idea that is used in this method is to basically reconstruct the harmonics at the multiples of the fundamental frequency ( 0 F ) rather than trying to improve them. The harmonics are produced, in the magnitude spectrum, using t...
To reduce the high-order harmonics produced by the high-power pulse width modulated (PWM) converters, selective harmonic elimination (SHE) scheme is commonly used due to its superior harmonic performance at low switching frequency. This Project proposes an active compensation method through the PWM control of SHE phase angle. An application example on a high-power PWM current-source rectifier (...
Harmonics is one of the major power quality problems for power systems. The harmonics can be eliminated by power filters such as passive, active, and hybrid. In this study, a new passive filter configuration has been improved in addition to the existing passive filter configurations. Conventional hybrid passive filters are not successful to compensate rapidly changing reactive power demand. The...
The harmonics produced by the nonlinear magnetization of superparamagnetic nanoparticles have been utilized in a number of budding medical devices. Here we expand on an earlier technique for quantitatively measuring nanoparticle temperature in a purely ac field by including the presence of a static field. The ability to quantify nanoparticle temperature by tracking changes in the 4th/2nd harmon...
Generation efficiency of the high-order harmonics of femtosecond Ti:sapphire laser pulses was improved by phasematched propagation in the guiding channel. The harmonics around the 49th harmonic (16 nm) were enhanced by two orders of magnitude compared to those in the plateau with a 7-mm-long, self-guided pulse in Ne. High-harmonic conversion efficiency of 10−6 was obtained, producing > nJ harmo...
With the development of modern industrial technology a large number of non-linear loads are used in power system, which causes harmonic distortion in the power system. At the same time the power quality and safe operation becomes inferior. Therefore mitigation of harmonics is very necessary under the situation. This paper presents the design of two passive filters to reduce the current harmonic...
Subfemtosecond light pulses can be obtained by superposing several high harmonics of an intense laser pulse. Provided that the harmonics are emitted simultaneously, increasing their number should result in shorter pulses. However, we found that the high harmonics were not synchronized on an attosecond time scale, thus setting a lower limit to the achievable x-ray pulse duration. We showed that ...
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