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35 articles for “Frequency Modulation (FM)”
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Research ArticleOpen accessIn the abstractPerformance Analysis of IEEE 802.16d using Forward Error CorrectionVenkatesh Sekar, V. Palanisamy, K. BaskaranProblem statement: Worldwide Interoperability for Microwave Access is the broadband wireless technology for terrestrial broadcast services in Metropolitan Area Networks. This BWA technology is based on Orthogonal Frequency Division Multiplex (OFDM) technology and considers the radio frequency range up to 2-11 GHz and 10-66 GHz. The objective of this research work is the performance analysis of AWGN, SUI-1 and SUI-2 … …Journal of Computer Science, Vol. 7, Issue 3 · 9 Mar 2011 · 7,336 accessesView PDFCite
Research ArticleOpen accessIn the abstractComparative Studies on the Performance of Low Power Transmitters for Wireless Sensor NodesT. Sasilatha, J. RajaProblem statement: Power consumption was one of the most challenging aspects to design low power wireless sensor nodes. The objectives of the study were to (i) Design low voltage, low power transmitters for wireless sensor nodes and (ii) Compare and analyze the performance of the transmitters. Approach: The transmitters employed direct digital modulation scheme to reduce the power consumption of … …Journal of Computer Science, Vol. 5, Issue 2 · 28 Feb 2009 · 7,450 accessesView PDFCite
Research ArticleOpen accessIn the abstractFPGA Based SPWM Bridge InverterM. N. Md Isa, M.I. Ahmad, Sohiful A.Z. Murad, M.K. Md ArshadThis study presents methodology to generate sinusoidal pulse width modulation (SPWM) signal using Field Programmable Gate Array, FPGA technology. We discussed the unipolar switching scheme and the methodology to generate the signal with the predetermined switching frequencies. Simulation on the designed pulses was conducted using Altera Max Plus II simulation tools. This simulation method was used to get the desired … …American Journal of Applied Sciences, Vol. 4, Issue 8 · 31 Aug 2007 · 7,396 accessesView PDFCite
Research ArticleOpen accessIn the abstractEffects of Low Frequencies on Three Phase Induction Motor Performance Operating in Close Proximity to Rated SpeedQazem Jaber, Qais Naman, Mahdi ShamaseenVariable speed drives (VSD) are adhered to induction motors in most of the present industrial applications. And since the world has become more conscientious to energy saving, inverters established them selves in domestic buildings and industry. Square wave inverters generate dominant harmonics of the 5th, 7th, 11th and 13th order. Inverters based on PWM strategy produce much higher harmonic order … …American Journal of Applied Sciences, Vol. 4, Issue 5 · 31 May 2007 · 7,516 accessesView PDFCite
Research ArticleOpen accessIn the abstractDC Motor Control Predictive ModelsRavinesh Singh, Godfrey C. Onwubolu, Krishnileshwar Singh, Ritnesh RamDC motor speed and position controls are fundamental in vehicles in general and robotics in particular. This study presents a mathematical model for correlating the interactions of some DC motor control parameters such as duty cycle, terminal voltage, frequency and load on some responses such as output current, voltage and speed by means of response surface methodology. For this exercise, … …American Journal of Applied Sciences, Vol. 3, Issue 11 · 30 Nov 2006 · 7,015 accessesView PDFCite
Research ArticleOpen accessIn the abstractImproving Mechanical Characteristics of Inverter-induction Motor Drive SystemHussein Sarhan, Rateb IssaAn inverter-three-phase squirrel-cage induction motor drive system with improved mechanical characteristics is presented. The proposed system provides mechanical characteristics with constant maximum torque or increased maximum torque and reduced slip speed at frequencies below the nominal frequency. The control algorithm is based on the constant volts per hertz principle using two improvement techniques: keeping maximum torque constant or keeping magnetic … …American Journal of Applied Sciences, Vol. 3, Issue 8 · 31 Aug 2006 · 7,659 accessesView PDFCite
Research ArticleOpen accessIn the abstractDetermination of Absorption Coefficients and Thermal Diffusivity of Modulated Doped GaAlAs/GaAs Heterostructure by Photothermal Deflection SpectroscopyS. Aloulou, M. Fathallah, M. Oueslati, A. SfaxiWe report in this study theoretical and experimental studies of photothermal deflection spectroscopy (PDS) for planar doped heterostructures AlGaAs/GaAs. The PDS spectra at T=300K are recorded by varying the wavelength of the excited radiation for different modulation frequencies. They show two different regions related to the fundamental electronic transitions from GaAs and Si doped AlGaAs. The DX levels have been … …American Journal of Applied Sciences, Vol. 2, Issue 10 · 31 Oct 2005 · 7,262 accessesView PDFCite
Research ArticleOpen accessIn the abstractComparison of Bit Error Rate Performance of Multi Tone Channel Utilising De-OQPSK and De-Off Set 16 QAM with Guard IntervalIbrahim A.Z. QatawnehDigital communications systems use Multi tone Channel (MC) transmission techniques with differentially encoded and differentially coherent demodulation. Today there are two principle MC application, one is for the high speed digital subscriber loop and the other is for the broadcasting of digital audio and video signals. In this study the comparison of multi carriers with OQPSK and Offset 16 QAM … …Journal of Computer Science, Vol. 1, Issue 3 · 30 Sep 2005 · 6,847 accessesView PDFCite
Research ArticleOpen accessIn the abstractImplementation of a Novel Concatenated FEC by RS and Irregular Turbo Codes on OFDM SystemsA. Shanmugam, A. R. Abdul Rajak, S. Vishwanath, R. UpendraCode Division Multiple Access (CDMA) performs well in a multi-cellular environment where a single frequency is used in all cells. Code Division Multiple Access (CDMA) has severe problems associated with multipath and Channel news. One possible problem is that the receiver may require a very large dynamic range in order to handle the large signal strength variation among users. Due … …American Journal of Applied Sciences, Vol. 2, Issue 5 · 31 May 2005 · 7,039 accessesView PDFCite
Research ArticleOpen accessAll words, across the recordNeurofeedback Therapy Meets Transformers: Rewiring Sleep Disorders Through AI-Driven EEG ModulationAmala Ann KA, Vaidhehi VSleep disorders such as insomnia, sleep Apnea, and hypersomnia significantly impair neurophysiological functioning, yet conventional treatments like Cognitive Behavioral Therapy for Insomnia (CBT-I) remain resource-intensive and difficult to personalize. This study introduces a novel AI-powered neurofeedback simulation framework designed to detect dysregulated EEG frequency band activity across sleep stages and simulate targeted interventions. A Transformer-based model serves as the core … …Journal of Computer Science, Vol. 22, Issue 2 · 3 Mar 2026 · 1,674 accessesView PDFCite