16 articles for “Noise Spectrum”

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Research ArticleOpen accessIn the abstractFabrication of X-Ray Optics for a Portable Total Reflection X-Ray Fluorescence Spectrometer Using Electrolytic in Process Dressing Grinding and Magnetorheological FinishingShinsuke Kunimura, Hiroshi Kasuga, Yosuke Hachisu, Hitoshi OhmoriProblem statement: A portable X-ray elemental analyzer (total reflection X-ray fluorescence spectrometer) has been developed since 2006 and this spectrometer made it possible to perform ultra trace elemental determination. The intensity of scattered X-rays that become background noise in a spectrum is reduced with the improvement in surface accuracy of an X-ray reflector used in the portable spectrometer and therefore … …Current Research in Nanotechnology, Vol. 1, Issue 2 · 21 Jun 2011 · 7,293 accessesView PDF Cite

Research ArticleOpen accessIn the abstractCooperative Sensing in Cognitive Radio Networks-Avoid Non-Perfect Reporting ChannelRania A. Mokhtar, Sabira Khatun, B. M. Ali, A. RamliProblem statement: Cognitive radio is a candidate technology for more efficient spectrum utilization systems based on opportunistic spectrum sharing. However, a common assumption regarding cognitive radios is that they are unlicensed spectrum users that should defer to (avoid interfering with) existing primary sources. Therefore effective sensing of primary users was a major focus of current research. Cooperative spectrum sensing had … …American Journal of Engineering and Applied Sciences, Vol. 2, Issue 2 · 30 Jun 2009 · 7,734 accessesView PDF Cite

Research ArticleOpen accessIn the abstractReed Solomon Coding for Frequency Hopping Spread Spectrum in Jamming EnvironmentOthman Sidek, Abid YahyaFrequency hopping spread spectrum with noncoherent M-ary frequency shift keying system is considered. In this study Reed Solomon codes RS (255, 223) are employed in a standard error correction role to provide some Anti-Jamming (AJ) capability with 8-bit symbols. Noise has been added to RS encoded data, which is demodulated at RS decoder perfectly. Matlab simulations have been implemented for … …American Journal of Applied Sciences, Vol. 5, Issue 10 · 31 Oct 2008 · 7,399 accessesView PDF Cite

Research ArticleOpen accessIn the abstractMixed Mode EMI Noise Level Measurement in SMPSR. Dhanasekaran, M. Rajaram, S. N. SivanandamFast switching in SMPS generate large amount of Electromagnetic Interference (EMI).The proposed method to determine Common Mode (CM) and Differential Mode (DM) noise of a low power Switched Mode Power Supply (SMPS) using two-probe approach i.e. using one current probe as an injecting probe and other current probe as receiving probe Common Mode (CM) noise is measured between power line … …American Journal of Applied Sciences, Vol. 3, Issue 5 · 31 May 2006 · 7,410 accessesView PDF Cite

Research ArticleOpen accessIn the abstractLow-Cost Encoding Device for Optical Code Division Multiple Access SystemMohammad Syuhaimi Ab-Rahman, Boonchuan Ng, Norshilawati Mohamad Ibrahim, Sahbudin ShaariProblem statement: Instead of using Fiber Bragg Grating (FBG) to develop the coded spectrums, which consist of expensive elements, the grating also are highly sensitive to environmental changes and this will contribute to the increment of capital and operational expenditures (CAPEX and OPEX). Approach: This study presented the development of low-cost 16-ports encoding device for Optical Code Division Multiple Access … …American Journal of Engineering and Applied Sciences, Vol. 2, Issue 2 · 30 Jun 2009 · 7,638 accessesView PDF Cite

Research ArticleOpen accessAll words, across the recordAN EFFICIENT POWER REDUCTION TECHNIQUE IN ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING SYSTEM USING TONE RESERVATIONV. Nandalal, S. SophiaIn a basic communication system, the data’s are modulated onto a single carrier frequency. The available bandwidth is then totally occupied by each symbol. This kind of system can lead to Inter-Symbol-Interference (ISI) in case of frequency selective fading. The basic idea of Orthogonal Frequency Division Multiplexing (OFDM) is to divide the available spectrum into several orthogonal sub channels so … …Journal of Computer Science, Vol. 9, Issue 9 · 6 Aug 2013 · 6,471 accessesView PDF Cite